1Config(3pm)            Perl Programmers Reference Guide            Config(3pm)
2
3
4

NAME

6       Config - access Perl configuration information
7

SYNOPSIS

9           use Config;
10           if ($Config{usethreads}) {
11               print "has thread support\n"
12           }
13
14           use Config qw(myconfig config_sh config_vars config_re);
15
16           print myconfig();
17
18           print config_sh();
19
20           print config_re();
21
22           config_vars(qw(osname archname));
23

DESCRIPTION

25       The Config module contains all the information that was available to
26       the "Configure" program at Perl build time (over 900 values).
27
28       Shell variables from the config.sh file (written by Configure) are
29       stored in the readonly-variable %Config, indexed by their names.
30
31       Values stored in config.sh as 'undef' are returned as undefined values.
32       The perl "exists" function can be used to check if a named variable
33       exists.
34
35       For a description of the variables, please have a look at the Glossary
36       file, as written in the Porting folder, or use the url:
37       https://github.com/Perl/perl5/blob/blead/Porting/Glossary
38
39       myconfig()
40           Returns a textual summary of the major perl configuration values.
41           See also "-V" in "Command Switches" in perlrun.
42
43       config_sh()
44           Returns the entire perl configuration information in the form of
45           the original config.sh shell variable assignment script.
46
47       config_re($regex)
48           Like config_sh() but returns, as a list, only the config entries
49           who's names match the $regex.
50
51       config_vars(@names)
52           Prints to STDOUT the values of the named configuration variable.
53           Each is printed on a separate line in the form:
54
55             name='value';
56
57           Names which are unknown are output as "name='UNKNOWN';".  See also
58           "-V:name" in "Command Switches" in perlrun.
59
60       bincompat_options()
61           Returns a list of C pre-processor options used when compiling this
62           perl binary, which affect its binary compatibility with extensions.
63           "bincompat_options()" and "non_bincompat_options()" are shown
64           together in the output of "perl -V" as Compile-time options.
65
66       non_bincompat_options()
67           Returns a list of C pre-processor options used when compiling this
68           perl binary, which do not affect binary compatibility with
69           extensions.
70
71       compile_date()
72           Returns the compile date (as a string), equivalent to what is shown
73           by "perl -V"
74
75       local_patches()
76           Returns a list of the names of locally applied patches, equivalent
77           to what is shown by "perl -V".
78
79       header_files()
80           Returns a list of the header files that should be used as
81           dependencies for XS code, for this version of Perl on this
82           platform.
83

EXAMPLE

85       Here's a more sophisticated example of using %Config:
86
87           use Config;
88           use strict;
89
90           my %sig_num;
91           my @sig_name;
92           unless($Config{sig_name} && $Config{sig_num}) {
93               die "No sigs?";
94           } else {
95               my @names = split ' ', $Config{sig_name};
96               @sig_num{@names} = split ' ', $Config{sig_num};
97               foreach (@names) {
98                   $sig_name[$sig_num{$_}] ||= $_;
99               }
100           }
101
102           print "signal #17 = $sig_name[17]\n";
103           if ($sig_num{ALRM}) {
104               print "SIGALRM is $sig_num{ALRM}\n";
105           }
106

WARNING

108       Because this information is not stored within the perl executable
109       itself it is possible (but unlikely) that the information does not
110       relate to the actual perl binary which is being used to access it.
111
112       The Config module is installed into the architecture and version
113       specific library directory ($Config{installarchlib}) and it checks the
114       perl version number when loaded.
115
116       The values stored in config.sh may be either single-quoted or double-
117       quoted. Double-quoted strings are handy for those cases where you need
118       to include escape sequences in the strings. To avoid runtime variable
119       interpolation, any "$" and "@" characters are replaced by "\$" and
120       "\@", respectively. This isn't foolproof, of course, so don't embed
121       "\$" or "\@" in double-quoted strings unless you're willing to deal
122       with the consequences. (The slashes will end up escaped and the "$" or
123       "@" will trigger variable interpolation)
124

GLOSSARY

126       Most "Config" variables are determined by the "Configure" script on
127       platforms supported by it (which is most UNIX platforms).  Some
128       platforms have custom-made "Config" variables, and may thus not have
129       some of the variables described below, or may have extraneous variables
130       specific to that particular port.  See the port specific documentation
131       in such cases.
132
133   _
134       "_a"
135           From Unix.U:
136
137           This variable defines the extension used for ordinary library
138           files.  For unix, it is .a.  The . is included.  Other possible
139           values include .lib.
140
141       "_exe"
142           From Unix.U:
143
144           This variable defines the extension used for executable files.
145           "DJGPP", Cygwin and OS/2 use .exe.  Stratus "VOS" uses .pm.  On
146           operating systems which do not require a specific extension for
147           executable files, this variable is empty.
148
149       "_o"
150           From Unix.U:
151
152           This variable defines the extension used for object files.  For
153           unix, it is .o.  The . is included.  Other possible values include
154           .obj.
155
156   a
157       "afs"
158           From afs.U:
159
160           This variable is set to "true" if "AFS" (Andrew File System) is
161           used on the system, "false" otherwise.  It is possible to override
162           this with a hint value or command line option, but you'd better
163           know what you are doing.
164
165       "afsroot"
166           From afs.U:
167
168           This variable is by default set to /afs. In the unlikely case this
169           is not the correct root, it is possible to override this with a
170           hint value or command line option.  This will be used in subsequent
171           tests for AFSness in the configure and test process.
172
173       "alignbytes"
174           From alignbytes.U:
175
176           This variable holds the number of bytes required to align a
177           double-- or a long double when applicable. Usual values are 2, 4
178           and 8.  The default is eight, for safety.
179
180       "aphostname"
181           From d_gethname.U:
182
183           This variable contains the command which can be used to compute the
184           host name. The command is fully qualified by its absolute path, to
185           make it safe when used by a process with super-user privileges.
186
187       "api_revision"
188           From patchlevel.U:
189
190           The three variables, api_revision, api_version, and api_subversion,
191           specify the version of the oldest perl binary compatible with the
192           present perl.  In a full version string such as 5.6.1, api_revision
193           is the 5.  Prior to 5.5.640, the format was a floating point
194           number, like 5.00563.
195
196           perl.c:incpush() and lib/lib.pm will automatically search in
197           $sitelib/.. for older directories back to the limit specified by
198           these api_ variables.  This is only useful if you have a perl
199           library directory tree structured like the default one.  See
200           "INSTALL" for how this works.  The versioned site_perl directory
201           was introduced in 5.005, so that is the lowest possible value.  The
202           version list appropriate for the current system is determined in
203           inc_version_list.U.
204
205           "XXX" To do:  Since compatibility can depend on compile time
206           options (such as bincompat, longlong, etc.) it should (perhaps) be
207           set by Configure, but currently it isn't.  Currently, we read a
208           hard-wired value from patchlevel.h.  Perhaps what we ought to do is
209           take the hard-wired value from patchlevel.h but then modify it if
210           the current Configure options warrant.  patchlevel.h then would use
211           an #ifdef guard.
212
213       "api_subversion"
214           From patchlevel.U:
215
216           The three variables, api_revision, api_version, and api_subversion,
217           specify the version of the oldest perl binary compatible with the
218           present perl.  In a full version string such as 5.6.1,
219           api_subversion is the 1.  See api_revision for full details.
220
221       "api_version"
222           From patchlevel.U:
223
224           The three variables, api_revision, api_version, and api_subversion,
225           specify the version of the oldest perl binary compatible with the
226           present perl.  In a full version string such as 5.6.1, api_version
227           is the 6.  See api_revision for full details.  As a special case,
228           5.5.0 is rendered in the old-style as 5.005.  (In the 5.005_0x
229           maintenance series, this was the only versioned directory in
230           $sitelib.)
231
232       "api_versionstring"
233           From patchlevel.U:
234
235           This variable combines api_revision, api_version, and
236           api_subversion in a format such as 5.6.1 (or 5_6_1) suitable for
237           use as a directory name.  This is filesystem dependent.
238
239       "ar"
240           From Loc.U:
241
242           This variable is used internally by Configure to determine the full
243           pathname (if any) of the ar program.  After Configure runs, the
244           value is reset to a plain "ar" and is not useful.
245
246       "archlib"
247           From archlib.U:
248
249           This variable holds the name of the directory in which the user
250           wants to put architecture-dependent public library files for
251           $package.  It is most often a local directory such as
252           /usr/local/lib.  Programs using this variable must be prepared to
253           deal with filename expansion.
254
255       "archlibexp"
256           From archlib.U:
257
258           This variable is the same as the archlib variable, but is filename
259           expanded at configuration time, for convenient use.
260
261       "archname"
262           From archname.U:
263
264           This variable is a short name to characterize the current
265           architecture.  It is used mainly to construct the default archlib.
266
267       "archname64"
268           From use64bits.U:
269
270           This variable is used for the 64-bitness part of $archname.
271
272       "archobjs"
273           From Unix.U:
274
275           This variable defines any additional objects that must be linked in
276           with the program on this architecture.  On unix, it is usually
277           empty.  It is typically used to include emulations of unix calls or
278           other facilities.  For perl on OS/2, for example, this would
279           include os2/os2.obj.
280
281       "asctime_r_proto"
282           From d_asctime_r.U:
283
284           This variable encodes the prototype of asctime_r.  It is zero if
285           d_asctime_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
286           of reentr.h if d_asctime_r is defined.
287
288       "awk"
289           From Loc.U:
290
291           This variable is used internally by Configure to determine the full
292           pathname (if any) of the awk program.  After Configure runs, the
293           value is reset to a plain "awk" and is not useful.
294
295   b
296       "baserev"
297           From baserev.U:
298
299           The base revision level of this package, from the .package file.
300
301       "bash"
302           From Loc.U:
303
304           This variable is defined but not used by Configure.  The value is
305           the empty string and is not useful.
306
307       "bin"
308           From bin.U:
309
310           This variable holds the name of the directory in which the user
311           wants to put publicly executable images for the package in
312           question.  It is most often a local directory such as
313           /usr/local/bin. Programs using this variable must be prepared to
314           deal with ~name substitution.
315
316       "bin_ELF"
317           From dlsrc.U:
318
319           This variable saves the result from configure if generated binaries
320           are in "ELF" format. Only set to defined when the test has actually
321           been performed, and the result was positive.
322
323       "binexp"
324           From bin.U:
325
326           This is the same as the bin variable, but is filename expanded at
327           configuration time, for use in your makefiles.
328
329       "bison"
330           From Loc.U:
331
332           This variable is used internally by Configure to determine the full
333           pathname (if any) of the bison program.  After Configure runs, the
334           value is reset to a plain "bison" and is not useful.
335
336       "byacc"
337           From Loc.U:
338
339           This variable is used internally by Configure to determine the full
340           pathname (if any) of the byacc program.  After Configure runs, the
341           value is reset to a plain "byacc" and is not useful.
342
343       "byteorder"
344           From byteorder.U:
345
346           This variable holds the byte order in a "UV". In the following,
347           larger digits indicate more significance.  The variable byteorder
348           is either 4321 on a big-endian machine, or 1234 on a little-endian,
349           or 87654321 on a Cray ... or 3412 with weird order !
350
351   c
352       "c" From n.U:
353
354           This variable contains the \c string if that is what causes the
355           echo command to suppress newline.  Otherwise it is null.  Correct
356           usage is $echo $n "prompt for a question: $c".
357
358       "castflags"
359           From d_castneg.U:
360
361           This variable contains a flag that precise difficulties the
362           compiler has casting odd floating values to unsigned long: 0 = ok 1
363           = couldn't cast < 0 2 = couldn't cast >= 0x80000000 4 = couldn't
364           cast in argument expression list
365
366       "cat"
367           From Loc.U:
368
369           This variable is used internally by Configure to determine the full
370           pathname (if any) of the cat program.  After Configure runs, the
371           value is reset to a plain "cat" and is not useful.
372
373       "cc"
374           From cc.U:
375
376           This variable holds the name of a command to execute a C compiler
377           which can resolve multiple global references that happen to have
378           the same name.  Usual values are "cc" and "gcc".  Fervent "ANSI"
379           compilers may be called "c89".  "AIX" has xlc.
380
381       "cccdlflags"
382           From dlsrc.U:
383
384           This variable contains any special flags that might need to be
385           passed with "cc -c" to compile modules to be used to create a
386           shared library that will be used for dynamic loading.  For hpux,
387           this should be +z.  It is up to the makefile to use it.
388
389       "ccdlflags"
390           From dlsrc.U:
391
392           This variable contains any special flags that might need to be
393           passed to cc to link with a shared library for dynamic loading.  It
394           is up to the makefile to use it.  For sunos 4.1, it should be
395           empty.
396
397       "ccflags"
398           From ccflags.U:
399
400           This variable contains any additional C compiler flags desired by
401           the user.  It is up to the Makefile to use this.
402
403       "ccflags_uselargefiles"
404           From uselfs.U:
405
406           This variable contains the compiler flags needed by large file
407           builds and added to ccflags by hints files.
408
409       "ccname"
410           From Checkcc.U:
411
412           This can set either by hints files or by Configure.  If using gcc,
413           this is gcc, and if not, usually equal to cc, unimpressive, no?
414           Some platforms, however, make good use of this by storing the
415           flavor of the C compiler being used here.  For example if using the
416           Sun WorkShop suite, ccname will be "workshop".
417
418       "ccsymbols"
419           From Cppsym.U:
420
421           The variable contains the symbols defined by the C compiler alone.
422           The symbols defined by cpp or by cc when it calls cpp are not in
423           this list, see cppsymbols and cppccsymbols.  The list is a space-
424           separated list of symbol=value tokens.
425
426       "ccversion"
427           From Checkcc.U:
428
429           This can set either by hints files or by Configure.  If using a
430           (non-gcc) vendor cc, this variable may contain a version for the
431           compiler.
432
433       "cf_by"
434           From cf_who.U:
435
436           Login name of the person who ran the Configure script and answered
437           the questions. This is used to tag both config.sh and config_h.SH.
438
439       "cf_email"
440           From cf_email.U:
441
442           Electronic mail address of the person who ran Configure. This can
443           be used by units that require the user's e-mail, like MailList.U.
444
445       "cf_time"
446           From cf_who.U:
447
448           Holds the output of the "date" command when the configuration file
449           was produced. This is used to tag both config.sh and config_h.SH.
450
451       "charbits"
452           From charsize.U:
453
454           This variable contains the value of the "CHARBITS" symbol, which
455           indicates to the C program how many bits there are in a character.
456
457       "charsize"
458           From charsize.U:
459
460           This variable contains the value of the "CHARSIZE" symbol, which
461           indicates to the C program how many bytes there are in a character.
462
463       "chgrp"
464           From Loc.U:
465
466           This variable is defined but not used by Configure.  The value is
467           the empty string and is not useful.
468
469       "chmod"
470           From Loc.U:
471
472           This variable is used internally by Configure to determine the full
473           pathname (if any) of the chmod program.  After Configure runs, the
474           value is reset to a plain "chmod" and is not useful.
475
476       "chown"
477           From Loc.U:
478
479           This variable is defined but not used by Configure.  The value is
480           the empty string and is not useful.
481
482       "clocktype"
483           From d_times.U:
484
485           This variable holds the type returned by times(). It can be long,
486           or clock_t on "BSD" sites (in which case <sys/types.h> should be
487           included).
488
489       "comm"
490           From Loc.U:
491
492           This variable is used internally by Configure to determine the full
493           pathname (if any) of the comm program.  After Configure runs, the
494           value is reset to a plain "comm" and is not useful.
495
496       "compiler_warning"
497           From compiler_warning.U:
498
499           This variable holds the command to check if the file specified as a
500           parameter contains a compiler warning
501
502       "compress"
503           From Loc.U:
504
505           This variable is defined but not used by Configure.  The value is
506           the empty string and is not useful.
507
508       "config_arg0"
509           From Options.U:
510
511           This variable contains the string used to invoke the Configure
512           command, as reported by the shell in the $0 variable.
513
514       "config_argc"
515           From Options.U:
516
517           This variable contains the number of command-line arguments passed
518           to Configure, as reported by the shell in the $# variable.  The
519           individual arguments are stored as variables config_arg1,
520           config_arg2, etc.
521
522       "config_args"
523           From Options.U:
524
525           This variable contains a single string giving the command-line
526           arguments passed to Configure. Spaces within arguments, quotes, and
527           escaped characters are not correctly preserved.  To reconstruct the
528           command line, you must assemble the individual command line pieces,
529           given in config_arg[0-9]*.
530
531       "contains"
532           From contains.U:
533
534           This variable holds the command to do a grep with a proper return
535           status.  On most sane systems it is simply "grep".  On insane
536           systems it is a grep followed by a cat followed by a test.  This
537           variable is primarily for the use of other Configure units.
538
539       "cp"
540           From Loc.U:
541
542           This variable is used internally by Configure to determine the full
543           pathname (if any) of the cp program.  After Configure runs, the
544           value is reset to a plain "cp" and is not useful.
545
546       "cpio"
547           From Loc.U:
548
549           This variable is defined but not used by Configure.  The value is
550           the empty string and is not useful.
551
552       "cpp"
553           From Loc.U:
554
555           This variable is used internally by Configure to determine the full
556           pathname (if any) of the cpp program.  After Configure runs, the
557           value is reset to a plain "cpp" and is not useful.
558
559       "cpp_stuff"
560           From cpp_stuff.U:
561
562           This variable contains an identification of the concatenation
563           mechanism used by the C preprocessor.
564
565       "cppccsymbols"
566           From Cppsym.U:
567
568           The variable contains the symbols defined by the C compiler when it
569           calls cpp.  The symbols defined by the cc alone or cpp alone are
570           not in this list, see ccsymbols and cppsymbols.  The list is a
571           space-separated list of symbol=value tokens.
572
573       "cppflags"
574           From ccflags.U:
575
576           This variable holds the flags that will be passed to the C pre-
577           processor. It is up to the Makefile to use it.
578
579       "cpplast"
580           From cppstdin.U:
581
582           This variable has the same functionality as cppminus, only it
583           applies to cpprun and not cppstdin.
584
585       "cppminus"
586           From cppstdin.U:
587
588           This variable contains the second part of the string which will
589           invoke the C preprocessor on the standard input and produce to
590           standard output.  This variable will have the value "-" if cppstdin
591           needs a minus to specify standard input, otherwise the value is "".
592
593       "cpprun"
594           From cppstdin.U:
595
596           This variable contains the command which will invoke a C
597           preprocessor on standard input and put the output to stdout. It is
598           guaranteed not to be a wrapper and may be a null string if no
599           preprocessor can be made directly available. This preprocessor
600           might be different from the one used by the C compiler. Don't
601           forget to append cpplast after the preprocessor options.
602
603       "cppstdin"
604           From cppstdin.U:
605
606           This variable contains the command which will invoke the C
607           preprocessor on standard input and put the output to stdout.  It is
608           primarily used by other Configure units that ask about preprocessor
609           symbols.
610
611       "cppsymbols"
612           From Cppsym.U:
613
614           The variable contains the symbols defined by the C preprocessor
615           alone.  The symbols defined by cc or by cc when it calls cpp are
616           not in this list, see ccsymbols and cppccsymbols.  The list is a
617           space-separated list of symbol=value tokens.
618
619       "crypt_r_proto"
620           From d_crypt_r.U:
621
622           This variable encodes the prototype of crypt_r.  It is zero if
623           d_crypt_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
624           of reentr.h if d_crypt_r is defined.
625
626       "cryptlib"
627           From d_crypt.U:
628
629           This variable holds -lcrypt or the path to a libcrypt.a archive if
630           the crypt() function is not defined in the standard C library. It
631           is up to the Makefile to use this.
632
633       "csh"
634           From Loc.U:
635
636           This variable is used internally by Configure to determine the full
637           pathname (if any) of the csh program.  After Configure runs, the
638           value is reset to a plain "csh" and is not useful.
639
640       "ctermid_r_proto"
641           From d_ctermid_r.U:
642
643           This variable encodes the prototype of ctermid_r.  It is zero if
644           d_ctermid_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
645           of reentr.h if d_ctermid_r is defined.
646
647       "ctime_r_proto"
648           From d_ctime_r.U:
649
650           This variable encodes the prototype of ctime_r.  It is zero if
651           d_ctime_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
652           of reentr.h if d_ctime_r is defined.
653
654   d
655       "d__fwalk"
656           From d__fwalk.U:
657
658           This variable conditionally defines "HAS__FWALK" if _fwalk() is
659           available to apply a function to all the file handles.
660
661       "d_accept4"
662           From d_accept4.U:
663
664           This variable conditionally defines HAS_ACCEPT4 if accept4() is
665           available to accept socket connections.
666
667       "d_access"
668           From d_access.U:
669
670           This variable conditionally defines "HAS_ACCESS" if the access()
671           system call is available to check for access permissions using real
672           IDs.
673
674       "d_accessx"
675           From d_accessx.U:
676
677           This variable conditionally defines the "HAS_ACCESSX" symbol, which
678           indicates to the C program that the accessx() routine is available.
679
680       "d_acosh"
681           From d_acosh.U:
682
683           This variable conditionally defines the "HAS_ACOSH" symbol, which
684           indicates to the C program that the acosh() routine is available.
685
686       "d_aintl"
687           From d_aintl.U:
688
689           This variable conditionally defines the "HAS_AINTL" symbol, which
690           indicates to the C program that the aintl() routine is available.
691           If copysignl is also present we can emulate modfl.
692
693       "d_alarm"
694           From d_alarm.U:
695
696           This variable conditionally defines the "HAS_ALARM" symbol, which
697           indicates to the C program that the alarm() routine is available.
698
699       "d_archlib"
700           From archlib.U:
701
702           This variable conditionally defines "ARCHLIB" to hold the pathname
703           of architecture-dependent library files for $package.  If $archlib
704           is the same as $privlib, then this is set to undef.
705
706       "d_asctime64"
707           From d_timefuncs64.U:
708
709           This variable conditionally defines the HAS_ASCTIME64 symbol, which
710           indicates to the C program that the asctime64 () routine is
711           available.
712
713       "d_asctime_r"
714           From d_asctime_r.U:
715
716           This variable conditionally defines the "HAS_ASCTIME_R" symbol,
717           which indicates to the C program that the asctime_r() routine is
718           available.
719
720       "d_asinh"
721           From d_asinh.U:
722
723           This variable conditionally defines the "HAS_ASINH" symbol, which
724           indicates to the C program that the asinh() routine is available.
725
726       "d_atanh"
727           From d_atanh.U:
728
729           This variable conditionally defines the "HAS_ATANH" symbol, which
730           indicates to the C program that the atanh() routine is available.
731
732       "d_atolf"
733           From atolf.U:
734
735           This variable conditionally defines the "HAS_ATOLF" symbol, which
736           indicates to the C program that the atolf() routine is available.
737
738       "d_atoll"
739           From atoll.U:
740
741           This variable conditionally defines the "HAS_ATOLL" symbol, which
742           indicates to the C program that the atoll() routine is available.
743
744       "d_attribute_always_inline"
745           From d_attribut.U:
746
747           This variable conditionally defines "HASATTRIBUTE_ALWAYS_INLINE",
748           which indicates that the C compiler can know that certain functions
749           should always be inlined.
750
751       "d_attribute_deprecated"
752           From d_attribut.U:
753
754           This variable conditionally defines "HASATTRIBUTE_DEPRECATED",
755           which indicates that "GCC" can handle the attribute for marking
756           deprecated APIs
757
758       "d_attribute_format"
759           From d_attribut.U:
760
761           This variable conditionally defines "HASATTRIBUTE_FORMAT", which
762           indicates the C compiler can check for printf-like formats.
763
764       "d_attribute_malloc"
765           From d_attribut.U:
766
767           This variable conditionally defines "HASATTRIBUTE_MALLOC", which
768           indicates the C compiler can understand functions as having malloc-
769           like semantics.
770
771       "d_attribute_nonnull"
772           From d_attribut.U:
773
774           This variable conditionally defines "HASATTRIBUTE_NONNULL", which
775           indicates that the C compiler can know that certain arguments must
776           not be "NULL", and will check accordingly at compile time.
777
778       "d_attribute_noreturn"
779           From d_attribut.U:
780
781           This variable conditionally defines "HASATTRIBUTE_NORETURN", which
782           indicates that the C compiler can know that certain functions are
783           guaranteed never to return.
784
785       "d_attribute_pure"
786           From d_attribut.U:
787
788           This variable conditionally defines "HASATTRIBUTE_PURE", which
789           indicates that the C compiler can know that certain functions are
790           "pure" functions, meaning that they have no side effects, and only
791           rely on function input and/or global data for their results.
792
793       "d_attribute_unused"
794           From d_attribut.U:
795
796           This variable conditionally defines "HASATTRIBUTE_UNUSED", which
797           indicates that the C compiler can know that certain variables and
798           arguments may not always be used, and to not throw warnings if they
799           don't get used.
800
801       "d_attribute_warn_unused_result"
802           From d_attribut.U:
803
804           This variable conditionally defines
805           "HASATTRIBUTE_WARN_UNUSED_RESULT", which indicates that the C
806           compiler can know that certain functions have a return values that
807           must not be ignored, such as malloc() or open().
808
809       "d_backtrace"
810           From d_backtrace.U:
811
812           This variable conditionally defines the "HAS_BACKTRACE" symbol,
813           which indicates to the C program that the backtrace() routine is
814           available to get a stack trace.
815
816       "d_bsd"
817           From Guess.U:
818
819           This symbol conditionally defines the symbol "BSD" when running on
820           a "BSD" system.
821
822       "d_bsdgetpgrp"
823           From d_getpgrp.U:
824
825           This variable conditionally defines "USE_BSD_GETPGRP" if getpgrp
826           needs one arguments whereas "USG" one needs none.
827
828       "d_bsdsetpgrp"
829           From d_setpgrp.U:
830
831           This variable conditionally defines "USE_BSD_SETPGRP" if setpgrp
832           needs two arguments whereas "USG" one needs none.  See also
833           d_setpgid for a "POSIX" interface.
834
835       "d_builtin_add_overflow"
836           From d_builtin_overflow.U:
837
838           This variable conditionally defines "HAS_BUILTIN_ADD_OVERFLOW",
839           which indicates that the compiler supports
840           __builtin_add_overflow(x,y,&z) for safely adding x and y into z
841           while checking for overflow.
842
843       "d_builtin_choose_expr"
844           From d_builtin.U:
845
846           This conditionally defines "HAS_BUILTIN_CHOOSE_EXPR", which
847           indicates that the compiler supports __builtin_choose_expr(x,y,z).
848           This built-in function is analogous to the "x?y:z" operator in C,
849           except that the expression returned has its type unaltered by
850           promotion rules. Also, the built-in function does not evaluate the
851           expression that was not chosen.
852
853       "d_builtin_expect"
854           From d_builtin.U:
855
856           This conditionally defines "HAS_BUILTIN_EXPECT", which indicates
857           that the compiler supports __builtin_expect(exp,c).  You may use
858           __builtin_expect to provide the compiler with branch prediction
859           information.
860
861       "d_builtin_mul_overflow"
862           From d_builtin_overflow.U:
863
864           This variable conditionally defines "HAS_BUILTIN_MUL_OVERFLOW",
865           which indicates that the compiler supports
866           __builtin_mul_overflow(x,y,&z) for safely multiplying x and y into
867           z while checking for overflow.
868
869       "d_builtin_sub_overflow"
870           From d_builtin_overflow.U:
871
872           This variable conditionally defines "HAS_BUILTIN_SUB_OVERFLOW",
873           which indicates that the compiler supports
874           __builtin_sub_overflow(x,y,&z) for safely subtracting y from x into
875           z while checking for overflow.
876
877       "d_c99_variadic_macros"
878           From d_c99_variadic.U:
879
880           This variable conditionally defines the HAS_C99_VARIADIC_MACROS
881           symbol, which indicates to the C program that C99 variadic macros
882           are available.
883
884       "d_casti32"
885           From d_casti32.U:
886
887           This variable conditionally defines CASTI32, which indicates
888           whether the C compiler can cast large floats to 32-bit ints.
889
890       "d_castneg"
891           From d_castneg.U:
892
893           This variable conditionally defines "CASTNEG", which indicates
894           whether the C compiler can cast negative float to unsigned.
895
896       "d_cbrt"
897           From d_cbrt.U:
898
899           This variable conditionally defines the "HAS_CBRT" symbol, which
900           indicates to the C program that the cbrt() (cube root) function is
901           available.
902
903       "d_chown"
904           From d_chown.U:
905
906           This variable conditionally defines the "HAS_CHOWN" symbol, which
907           indicates to the C program that the chown() routine is available.
908
909       "d_chroot"
910           From d_chroot.U:
911
912           This variable conditionally defines the "HAS_CHROOT" symbol, which
913           indicates to the C program that the chroot() routine is available.
914
915       "d_chsize"
916           From d_chsize.U:
917
918           This variable conditionally defines the "CHSIZE" symbol, which
919           indicates to the C program that the chsize() routine is available
920           to truncate files.  You might need a -lx to get this routine.
921
922       "d_class"
923           From d_class.U:
924
925           This variable conditionally defines the "HAS_CLASS" symbol, which
926           indicates to the C program that the class() routine is available.
927
928       "d_clearenv"
929           From d_clearenv.U:
930
931           This variable conditionally defines the "HAS_CLEARENV" symbol,
932           which indicates to the C program that the clearenv () routine is
933           available.
934
935       "d_closedir"
936           From d_closedir.U:
937
938           This variable conditionally defines "HAS_CLOSEDIR" if closedir() is
939           available.
940
941       "d_cmsghdr_s"
942           From d_cmsghdr_s.U:
943
944           This variable conditionally defines the "HAS_STRUCT_CMSGHDR"
945           symbol, which indicates that the struct cmsghdr is supported.
946
947       "d_copysign"
948           From d_copysign.U:
949
950           This variable conditionally defines the "HAS_COPYSIGN" symbol,
951           which indicates to the C program that the copysign() routine is
952           available.
953
954       "d_copysignl"
955           From d_copysignl.U:
956
957           This variable conditionally defines the "HAS_COPYSIGNL" symbol,
958           which indicates to the C program that the copysignl() routine is
959           available.  If aintl is also present we can emulate modfl.
960
961       "d_cplusplus"
962           From d_cplusplus.U:
963
964           This variable conditionally defines the "USE_CPLUSPLUS" symbol,
965           which indicates that a C++ compiler was used to compiled Perl and
966           will be used to compile extensions.
967
968       "d_crypt"
969           From d_crypt.U:
970
971           This variable conditionally defines the "CRYPT" symbol, which
972           indicates to the C program that the crypt() routine is available to
973           encrypt passwords and the like.
974
975       "d_crypt_r"
976           From d_crypt_r.U:
977
978           This variable conditionally defines the "HAS_CRYPT_R" symbol, which
979           indicates to the C program that the crypt_r() routine is available.
980
981       "d_csh"
982           From d_csh.U:
983
984           This variable conditionally defines the "CSH" symbol, which
985           indicates to the C program that the C-shell exists.
986
987       "d_ctermid"
988           From d_ctermid.U:
989
990           This variable conditionally defines "CTERMID" if ctermid() is
991           available to generate filename for terminal.
992
993       "d_ctermid_r"
994           From d_ctermid_r.U:
995
996           This variable conditionally defines the "HAS_CTERMID_R" symbol,
997           which indicates to the C program that the ctermid_r() routine is
998           available.
999
1000       "d_ctime64"
1001           From d_timefuncs64.U:
1002
1003           This variable conditionally defines the HAS_CTIME64 symbol, which
1004           indicates to the C program that the ctime64 () routine is
1005           available.
1006
1007       "d_ctime_r"
1008           From d_ctime_r.U:
1009
1010           This variable conditionally defines the "HAS_CTIME_R" symbol, which
1011           indicates to the C program that the ctime_r() routine is available.
1012
1013       "d_cuserid"
1014           From d_cuserid.U:
1015
1016           This variable conditionally defines the "HAS_CUSERID" symbol, which
1017           indicates to the C program that the cuserid() routine is available
1018           to get character login names.
1019
1020       "d_dbminitproto"
1021           From d_dbminitproto.U:
1022
1023           This variable conditionally defines the "HAS_DBMINIT_PROTO" symbol,
1024           which indicates to the C program that the system provides a
1025           prototype for the dbminit() function.  Otherwise, it is up to the
1026           program to supply one.
1027
1028       "d_difftime"
1029           From d_difftime.U:
1030
1031           This variable conditionally defines the "HAS_DIFFTIME" symbol,
1032           which indicates to the C program that the difftime() routine is
1033           available.
1034
1035       "d_difftime64"
1036           From d_timefuncs64.U:
1037
1038           This variable conditionally defines the HAS_DIFFTIME64 symbol,
1039           which indicates to the C program that the difftime64 () routine is
1040           available.
1041
1042       "d_dir_dd_fd"
1043           From d_dir_dd_fd.U:
1044
1045           This variable conditionally defines the "HAS_DIR_DD_FD" symbol,
1046           which indicates that the "DIR" directory stream type contains a
1047           member variable called dd_fd.
1048
1049       "d_dirfd"
1050           From d_dirfd.U:
1051
1052           This variable conditionally defines the "HAS_DIRFD" constant, which
1053           indicates to the C program that dirfd() is available to return the
1054           file descriptor of a directory stream.
1055
1056       "d_dirnamlen"
1057           From i_dirent.U:
1058
1059           This variable conditionally defines "DIRNAMLEN", which indicates to
1060           the C program that the length of directory entry names is provided
1061           by a d_namelen field.
1062
1063       "d_dladdr"
1064           From d_dladdr.U:
1065
1066           This variable conditionally defines the "HAS_DLADDR" symbol, which
1067           indicates to the C program that the dladdr() routine is available
1068           to get a stack trace.
1069
1070       "d_dlerror"
1071           From d_dlerror.U:
1072
1073           This variable conditionally defines the "HAS_DLERROR" symbol, which
1074           indicates to the C program that the dlerror() routine is available.
1075
1076       "d_dlopen"
1077           From d_dlopen.U:
1078
1079           This variable conditionally defines the "HAS_DLOPEN" symbol, which
1080           indicates to the C program that the dlopen() routine is available.
1081
1082       "d_dlsymun"
1083           From d_dlsymun.U:
1084
1085           This variable conditionally defines "DLSYM_NEEDS_UNDERSCORE", which
1086           indicates that we need to prepend an underscore to the symbol name
1087           before calling dlsym().
1088
1089       "d_dosuid"
1090           From d_dosuid.U:
1091
1092           This variable conditionally defines the symbol "DOSUID", which
1093           tells the C program that it should insert setuid emulation code on
1094           hosts which have setuid #! scripts disabled.
1095
1096       "d_double_has_inf"
1097           From longdblfio.U:
1098
1099           This variable conditionally defines the symbol "DOUBLE_HAS_INF"
1100           which indicates that the double type has an infinity.
1101
1102       "d_double_has_nan"
1103           From longdblfio.U:
1104
1105           This variable conditionally defines the symbol "DOUBLE_HAS_NAN"
1106           which indicates that the double type has a not-a-number.
1107
1108       "d_double_has_negative_zero"
1109           From longdblfio.U:
1110
1111           This variable conditionally defines the symbol
1112           "DOUBLE_HAS_NEGATIVE_ZERO" which indicates that the double type has
1113           a negative zero.
1114
1115       "d_double_has_subnormals"
1116           From longdblfio.U:
1117
1118           This variable conditionally defines the symbol
1119           "DOUBLE_HAS_SUBNORMALS" which indicates that the double type has
1120           subnormals (denormals).
1121
1122       "d_double_style_cray"
1123           From longdblfio.U:
1124
1125           This variable conditionally defines the symbol "DOUBLE_STYLE_CRAY"
1126           which indicates that the double is the 64-bit "CRAY" mainframe
1127           format.
1128
1129       "d_double_style_ibm"
1130           From longdblfio.U:
1131
1132           This variable conditionally defines the symbol "DOUBLE_STYLE_IBM",
1133           which indicates that the double is the 64-bit "IBM" mainframe
1134           format.
1135
1136       "d_double_style_ieee"
1137           From longdblfio.U:
1138
1139           This variable conditionally defines the symbol "DOUBLE_STYLE_IEEE",
1140           which indicates that the double is the 64-bit "IEEE" 754.
1141
1142       "d_double_style_vax"
1143           From longdblfio.U:
1144
1145           This variable conditionally defines the symbol "DOUBLE_STYLE_VAX",
1146           which indicates that the double is the 64-bit "VAX" format D or G.
1147
1148       "d_drand48_r"
1149           From d_drand48_r.U:
1150
1151           This variable conditionally defines the HAS_DRAND48_R symbol, which
1152           indicates to the C program that the drand48_r() routine is
1153           available.
1154
1155       "d_drand48proto"
1156           From d_drand48proto.U:
1157
1158           This variable conditionally defines the HAS_DRAND48_PROTO symbol,
1159           which indicates to the C program that the system provides a
1160           prototype for the drand48() function.  Otherwise, it is up to the
1161           program to supply one.
1162
1163       "d_dup2"
1164           From d_dup2.U:
1165
1166           This variable conditionally defines HAS_DUP2 if dup2() is available
1167           to duplicate file descriptors.
1168
1169       "d_dup3"
1170           From d_dup3.U:
1171
1172           This variable conditionally defines HAS_DUP3 if dup3() is available
1173           to duplicate file descriptors.
1174
1175       "d_duplocale"
1176           From d_newlocale.U:
1177
1178           This variable conditionally defines the "HAS_DUPLOCALE" symbol,
1179           which indicates to the C program that the duplocale() routine is
1180           available to duplicate a locale object.
1181
1182       "d_eaccess"
1183           From d_eaccess.U:
1184
1185           This variable conditionally defines the "HAS_EACCESS" symbol, which
1186           indicates to the C program that the eaccess() routine is available.
1187
1188       "d_endgrent"
1189           From d_endgrent.U:
1190
1191           This variable conditionally defines the "HAS_ENDGRENT" symbol,
1192           which indicates to the C program that the endgrent() routine is
1193           available for sequential access of the group database.
1194
1195       "d_endgrent_r"
1196           From d_endgrent_r.U:
1197
1198           This variable conditionally defines the "HAS_ENDGRENT_R" symbol,
1199           which indicates to the C program that the endgrent_r() routine is
1200           available.
1201
1202       "d_endhent"
1203           From d_endhent.U:
1204
1205           This variable conditionally defines "HAS_ENDHOSTENT" if
1206           endhostent() is available to close whatever was being used for host
1207           queries.
1208
1209       "d_endhostent_r"
1210           From d_endhostent_r.U:
1211
1212           This variable conditionally defines the "HAS_ENDHOSTENT_R" symbol,
1213           which indicates to the C program that the endhostent_r() routine is
1214           available.
1215
1216       "d_endnent"
1217           From d_endnent.U:
1218
1219           This variable conditionally defines "HAS_ENDNETENT" if endnetent()
1220           is available to close whatever was being used for network queries.
1221
1222       "d_endnetent_r"
1223           From d_endnetent_r.U:
1224
1225           This variable conditionally defines the "HAS_ENDNETENT_R" symbol,
1226           which indicates to the C program that the endnetent_r() routine is
1227           available.
1228
1229       "d_endpent"
1230           From d_endpent.U:
1231
1232           This variable conditionally defines "HAS_ENDPROTOENT" if
1233           endprotoent() is available to close whatever was being used for
1234           protocol queries.
1235
1236       "d_endprotoent_r"
1237           From d_endprotoent_r.U:
1238
1239           This variable conditionally defines the "HAS_ENDPROTOENT_R" symbol,
1240           which indicates to the C program that the endprotoent_r() routine
1241           is available.
1242
1243       "d_endpwent"
1244           From d_endpwent.U:
1245
1246           This variable conditionally defines the "HAS_ENDPWENT" symbol,
1247           which indicates to the C program that the endpwent() routine is
1248           available for sequential access of the passwd database.
1249
1250       "d_endpwent_r"
1251           From d_endpwent_r.U:
1252
1253           This variable conditionally defines the "HAS_ENDPWENT_R" symbol,
1254           which indicates to the C program that the endpwent_r() routine is
1255           available.
1256
1257       "d_endsent"
1258           From d_endsent.U:
1259
1260           This variable conditionally defines "HAS_ENDSERVENT" if
1261           endservent() is available to close whatever was being used for
1262           service queries.
1263
1264       "d_endservent_r"
1265           From d_endservent_r.U:
1266
1267           This variable conditionally defines the "HAS_ENDSERVENT_R" symbol,
1268           which indicates to the C program that the endservent_r() routine is
1269           available.
1270
1271       "d_eofnblk"
1272           From nblock_io.U:
1273
1274           This variable conditionally defines "EOF_NONBLOCK" if "EOF" can be
1275           seen when reading from a non-blocking I/O source.
1276
1277       "d_erf"
1278           From d_erf.U:
1279
1280           This variable conditionally defines the "HAS_ERF" symbol, which
1281           indicates to the C program that the erf() routine is available.
1282
1283       "d_erfc"
1284           From d_erfc.U:
1285
1286           This variable conditionally defines the "HAS_ERFC" symbol, which
1287           indicates to the C program that the erfc() routine is available.
1288
1289       "d_eunice"
1290           From Guess.U:
1291
1292           This variable conditionally defines the symbols "EUNICE" and "VAX",
1293           which alerts the C program that it must deal with idiosyncrasies of
1294           "VMS".
1295
1296       "d_exp2"
1297           From d_exp2.U:
1298
1299           This variable conditionally defines the HAS_EXP2 symbol, which
1300           indicates to the C program that the exp2() routine is available.
1301
1302       "d_expm1"
1303           From d_expm1.U:
1304
1305           This variable conditionally defines the HAS_EXPM1 symbol, which
1306           indicates to the C program that the expm1() routine is available.
1307
1308       "d_faststdio"
1309           From d_faststdio.U:
1310
1311           This variable conditionally defines the "HAS_FAST_STDIO" symbol,
1312           which indicates to the C program that the "fast stdio" is available
1313           to manipulate the stdio buffers directly.
1314
1315       "d_fchdir"
1316           From d_fchdir.U:
1317
1318           This variable conditionally defines the "HAS_FCHDIR" symbol, which
1319           indicates to the C program that the fchdir() routine is available.
1320
1321       "d_fchmod"
1322           From d_fchmod.U:
1323
1324           This variable conditionally defines the "HAS_FCHMOD" symbol, which
1325           indicates to the C program that the fchmod() routine is available
1326           to change mode of opened files.
1327
1328       "d_fchmodat"
1329           From d_fsat.U:
1330
1331           This variable conditionally defines the "HAS_FCHMODAT" symbol,
1332           which indicates the "POSIX" fchmodat() function is available.
1333
1334       "d_fchown"
1335           From d_fchown.U:
1336
1337           This variable conditionally defines the "HAS_FCHOWN" symbol, which
1338           indicates to the C program that the fchown() routine is available
1339           to change ownership of opened files.
1340
1341       "d_fcntl"
1342           From d_fcntl.U:
1343
1344           This variable conditionally defines the "HAS_FCNTL" symbol, and
1345           indicates whether the fcntl() function exists
1346
1347       "d_fcntl_can_lock"
1348           From d_fcntl_can_lock.U:
1349
1350           This variable conditionally defines the "FCNTL_CAN_LOCK" symbol and
1351           indicates whether file locking with fcntl() works.
1352
1353       "d_fd_macros"
1354           From d_fd_set.U:
1355
1356           This variable contains the eventual value of the "HAS_FD_MACROS"
1357           symbol, which indicates if your C compiler knows about the macros
1358           which manipulate an fd_set.
1359
1360       "d_fd_set"
1361           From d_fd_set.U:
1362
1363           This variable contains the eventual value of the "HAS_FD_SET"
1364           symbol, which indicates if your C compiler knows about the fd_set
1365           typedef.
1366
1367       "d_fdclose"
1368           From d_fdclose.U:
1369
1370           This variable conditionally defines the "HAS_FDCLOSE" symbol, which
1371           indicates to the C program that the fdclose() routine is available.
1372
1373       "d_fdim"
1374           From d_fdim.U:
1375
1376           This variable conditionally defines the "HAS_FDIM" symbol, which
1377           indicates to the C program that the fdim() routine is available.
1378
1379       "d_fds_bits"
1380           From d_fd_set.U:
1381
1382           This variable contains the eventual value of the "HAS_FDS_BITS"
1383           symbol, which indicates if your fd_set typedef contains the
1384           fds_bits member.  If you have an fd_set typedef, but the dweebs who
1385           installed it did a half-fast job and neglected to provide the
1386           macros to manipulate an fd_set, "HAS_FDS_BITS" will let us know how
1387           to fix the gaffe.
1388
1389       "d_fegetround"
1390           From d_fegetround.U:
1391
1392           This variable conditionally defines "HAS_FEGETROUND" if
1393           fegetround() is available to get the floating point rounding mode.
1394
1395       "d_ffs"
1396           From d_ffs.U:
1397
1398           This variable conditionally defines the "HAS_FFS" symbol, which
1399           indicates to the C program that the ffs() routine is available to
1400           find the first bit which is set in its integer argument.
1401
1402       "d_ffsl"
1403           From d_ffs.U:
1404
1405           This variable conditionally defines the "HAS_FFSL" symbol, which
1406           indicates to the C program that the ffsl() routine is available to
1407           find the first bit which is set in its long integer argument.
1408
1409       "d_fgetpos"
1410           From d_fgetpos.U:
1411
1412           This variable conditionally defines "HAS_FGETPOS" if fgetpos() is
1413           available to get the file position indicator.
1414
1415       "d_finite"
1416           From d_finite.U:
1417
1418           This variable conditionally defines the "HAS_FINITE" symbol, which
1419           indicates to the C program that the finite() routine is available.
1420
1421       "d_finitel"
1422           From d_finitel.U:
1423
1424           This variable conditionally defines the "HAS_FINITEL" symbol, which
1425           indicates to the C program that the finitel() routine is available.
1426
1427       "d_flexfnam"
1428           From d_flexfnam.U:
1429
1430           This variable conditionally defines the "FLEXFILENAMES" symbol,
1431           which indicates that the system supports filenames longer than 14
1432           characters.
1433
1434       "d_flock"
1435           From d_flock.U:
1436
1437           This variable conditionally defines "HAS_FLOCK" if flock() is
1438           available to do file locking.
1439
1440       "d_flockproto"
1441           From d_flockproto.U:
1442
1443           This variable conditionally defines the "HAS_FLOCK_PROTO" symbol,
1444           which indicates to the C program that the system provides a
1445           prototype for the flock() function.  Otherwise, it is up to the
1446           program to supply one.
1447
1448       "d_fma"
1449           From d_fma.U:
1450
1451           This variable conditionally defines the "HAS_FMA" symbol, which
1452           indicates to the C program that the fma() routine is available.
1453
1454       "d_fmax"
1455           From d_fmax.U:
1456
1457           This variable conditionally defines the "HAS_FMAX" symbol, which
1458           indicates to the C program that the fmax() routine is available.
1459
1460       "d_fmin"
1461           From d_fmin.U:
1462
1463           This variable conditionally defines the "HAS_FMIN" symbol, which
1464           indicates to the C program that the fmin() routine is available.
1465
1466       "d_fork"
1467           From d_fork.U:
1468
1469           This variable conditionally defines the "HAS_FORK" symbol, which
1470           indicates to the C program that the fork() routine is available.
1471
1472       "d_fp_class"
1473           From d_fp_class.U:
1474
1475           This variable conditionally defines the "HAS_FP_CLASS" symbol,
1476           which indicates to the C program that the fp_class() routine is
1477           available.
1478
1479       "d_fp_classify"
1480           From d_fpclassify.U:
1481
1482           This variable conditionally defines the "HAS_FP_CLASSIFY" symbol,
1483           which indicates to the C program that the fp_classify() routine is
1484           available.
1485
1486       "d_fp_classl"
1487           From d_fp_classl.U:
1488
1489           This variable conditionally defines the "HAS_FP_CLASSL" symbol,
1490           which indicates to the C program that the fp_classl() routine is
1491           available.
1492
1493       "d_fpathconf"
1494           From d_pathconf.U:
1495
1496           This variable conditionally defines the "HAS_FPATHCONF" symbol,
1497           which indicates to the C program that the pathconf() routine is
1498           available to determine file-system related limits and options
1499           associated with a given open file descriptor.
1500
1501       "d_fpclass"
1502           From d_fpclass.U:
1503
1504           This variable conditionally defines the "HAS_FPCLASS" symbol, which
1505           indicates to the C program that the fpclass() routine is available.
1506
1507       "d_fpclassify"
1508           From d_fpclassify.U:
1509
1510           This variable conditionally defines the "HAS_FPCLASSIFY" symbol,
1511           which indicates to the C program that the fpclassify() routine is
1512           available.
1513
1514       "d_fpclassl"
1515           From d_fpclassl.U:
1516
1517           This variable conditionally defines the "HAS_FPCLASSL" symbol,
1518           which indicates to the C program that the fpclassl() routine is
1519           available.
1520
1521       "d_fpgetround"
1522           From d_fpgetround.U:
1523
1524           This variable conditionally defines "HAS_FPGETROUND" if
1525           fpgetround() is available to get the floating point rounding mode.
1526
1527       "d_fpos64_t"
1528           From d_fpos64_t.U:
1529
1530           This symbol will be defined if the C compiler supports fpos64_t.
1531
1532       "d_freelocale"
1533           From d_newlocale.U:
1534
1535           This variable conditionally defines the "HAS_FREELOCALE" symbol,
1536           which indicates to the C program that the freelocale() routine is
1537           available to deallocates the resources associated with a locale
1538           object.
1539
1540       "d_frexpl"
1541           From d_frexpl.U:
1542
1543           This variable conditionally defines the "HAS_FREXPL" symbol, which
1544           indicates to the C program that the frexpl() routine is available.
1545
1546       "d_fs_data_s"
1547           From d_fs_data_s.U:
1548
1549           This variable conditionally defines the "HAS_STRUCT_FS_DATA"
1550           symbol, which indicates that the struct fs_data is supported.
1551
1552       "d_fseeko"
1553           From d_fseeko.U:
1554
1555           This variable conditionally defines the "HAS_FSEEKO" symbol, which
1556           indicates to the C program that the fseeko() routine is available.
1557
1558       "d_fsetpos"
1559           From d_fsetpos.U:
1560
1561           This variable conditionally defines "HAS_FSETPOS" if fsetpos() is
1562           available to set the file position indicator.
1563
1564       "d_fstatfs"
1565           From d_fstatfs.U:
1566
1567           This variable conditionally defines the "HAS_FSTATFS" symbol, which
1568           indicates to the C program that the fstatfs() routine is available.
1569
1570       "d_fstatvfs"
1571           From d_statvfs.U:
1572
1573           This variable conditionally defines the "HAS_FSTATVFS" symbol,
1574           which indicates to the C program that the fstatvfs() routine is
1575           available.
1576
1577       "d_fsync"
1578           From d_fsync.U:
1579
1580           This variable conditionally defines the "HAS_FSYNC" symbol, which
1581           indicates to the C program that the fsync() routine is available.
1582
1583       "d_ftello"
1584           From d_ftello.U:
1585
1586           This variable conditionally defines the "HAS_FTELLO" symbol, which
1587           indicates to the C program that the ftello() routine is available.
1588
1589       "d_ftime"
1590           From d_ftime.U:
1591
1592           This variable conditionally defines the "HAS_FTIME" symbol, which
1593           indicates that the ftime() routine exists.  The ftime() routine is
1594           basically a sub-second accuracy clock.
1595
1596       "d_futimes"
1597           From d_futimes.U:
1598
1599           This variable conditionally defines the "HAS_FUTIMES" symbol, which
1600           indicates to the C program that the futimes() routine is available.
1601
1602       "d_gai_strerror"
1603           From d_gai_strerror.U:
1604
1605           This variable conditionally defines the "HAS_GAI_STRERROR" symbol
1606           if the gai_strerror() routine is available and can be used to
1607           translate error codes returned by getaddrinfo() into human readable
1608           strings.
1609
1610       "d_Gconvert"
1611           From d_gconvert.U:
1612
1613           This variable holds what Gconvert is defined as to convert floating
1614           point numbers into strings.  By default, Configure sets "this"
1615           macro to use the first of gconvert, gcvt, or sprintf that pass
1616           sprintf-%g-like behavior tests.  If perl is using long doubles, the
1617           macro uses the first of the following functions that pass
1618           Configure's tests: qgcvt, sprintf (if Configure knows how to make
1619           sprintf format long doubles--see sPRIgldbl), gconvert, gcvt, and
1620           sprintf (casting to double).  The gconvert_preference and
1621           gconvert_ld_preference variables can be used to alter Configure's
1622           preferences, for doubles and long doubles, respectively.  If
1623           present, they contain a space-separated list of one or more of the
1624           above function names in the order they should be tried.
1625
1626           d_Gconvert may be set to override Configure with a platform-
1627           specific function.  If this function expects a double, a different
1628           value may need to be set by the uselongdouble.cbu call-back unit so
1629           that long doubles can be formatted without loss of precision.
1630
1631       "d_gdbm_ndbm_h_uses_prototypes"
1632           From i_ndbm.U:
1633
1634           This variable conditionally defines the "NDBM_H_USES_PROTOTYPES"
1635           symbol, which indicates that the gdbm-ndbm.h include file uses real
1636           "ANSI" C prototypes instead of K&R style function declarations. K&R
1637           style declarations are unsupported in C++, so the include file
1638           requires special handling when using a C++ compiler and this
1639           variable is undefined. Consult the different
1640           d_*ndbm_h_uses_prototypes variables to get the same information for
1641           alternative ndbm.h include files.
1642
1643       "d_gdbmndbm_h_uses_prototypes"
1644           From i_ndbm.U:
1645
1646           This variable conditionally defines the "NDBM_H_USES_PROTOTYPES"
1647           symbol, which indicates that the gdbm/ndbm.h include file uses real
1648           "ANSI" C prototypes instead of K&R style function declarations. K&R
1649           style declarations are unsupported in C++, so the include file
1650           requires special handling when using a C++ compiler and this
1651           variable is undefined. Consult the different
1652           d_*ndbm_h_uses_prototypes variables to get the same information for
1653           alternative ndbm.h include files.
1654
1655       "d_getaddrinfo"
1656           From d_getaddrinfo.U:
1657
1658           This variable conditionally defines the "HAS_GETADDRINFO" symbol,
1659           which indicates to the C program that the getaddrinfo() function is
1660           available.
1661
1662       "d_getcwd"
1663           From d_getcwd.U:
1664
1665           This variable conditionally defines the "HAS_GETCWD" symbol, which
1666           indicates to the C program that the getcwd() routine is available
1667           to get the current working directory.
1668
1669       "d_getenv_preserves_other_thread"
1670           From d_getenv_thread.U:
1671
1672           This variable conditionally defines the
1673           "GETENV_PRESERVES_OTHER_THREAD" symbol, which indicates to the C
1674           program that the getenv() system call does not zap the static
1675           buffer in a different thread.
1676
1677       "d_getespwnam"
1678           From d_getespwnam.U:
1679
1680           This variable conditionally defines "HAS_GETESPWNAM" if
1681           getespwnam() is available to retrieve enhanced (shadow) password
1682           entries by name.
1683
1684       "d_getfsstat"
1685           From d_getfsstat.U:
1686
1687           This variable conditionally defines the "HAS_GETFSSTAT" symbol,
1688           which indicates to the C program that the getfsstat() routine is
1689           available.
1690
1691       "d_getgrent"
1692           From d_getgrent.U:
1693
1694           This variable conditionally defines the "HAS_GETGRENT" symbol,
1695           which indicates to the C program that the getgrent() routine is
1696           available for sequential access of the group database.
1697
1698       "d_getgrent_r"
1699           From d_getgrent_r.U:
1700
1701           This variable conditionally defines the "HAS_GETGRENT_R" symbol,
1702           which indicates to the C program that the getgrent_r() routine is
1703           available.
1704
1705       "d_getgrgid_r"
1706           From d_getgrgid_r.U:
1707
1708           This variable conditionally defines the "HAS_GETGRGID_R" symbol,
1709           which indicates to the C program that the getgrgid_r() routine is
1710           available.
1711
1712       "d_getgrnam_r"
1713           From d_getgrnam_r.U:
1714
1715           This variable conditionally defines the "HAS_GETGRNAM_R" symbol,
1716           which indicates to the C program that the getgrnam_r() routine is
1717           available.
1718
1719       "d_getgrps"
1720           From d_getgrps.U:
1721
1722           This variable conditionally defines the "HAS_GETGROUPS" symbol,
1723           which indicates to the C program that the getgroups() routine is
1724           available to get the list of process groups.
1725
1726       "d_gethbyaddr"
1727           From d_gethbyad.U:
1728
1729           This variable conditionally defines the "HAS_GETHOSTBYADDR" symbol,
1730           which indicates to the C program that the gethostbyaddr() routine
1731           is available to look up hosts by their "IP" addresses.
1732
1733       "d_gethbyname"
1734           From d_gethbynm.U:
1735
1736           This variable conditionally defines the "HAS_GETHOSTBYNAME" symbol,
1737           which indicates to the C program that the gethostbyname() routine
1738           is available to look up host names in some data base or other.
1739
1740       "d_gethent"
1741           From d_gethent.U:
1742
1743           This variable conditionally defines "HAS_GETHOSTENT" if
1744           gethostent() is available to look up host names in some data base
1745           or another.
1746
1747       "d_gethname"
1748           From d_gethname.U:
1749
1750           This variable conditionally defines the "HAS_GETHOSTNAME" symbol,
1751           which indicates to the C program that the gethostname() routine may
1752           be used to derive the host name.
1753
1754       "d_gethostbyaddr_r"
1755           From d_gethostbyaddr_r.U:
1756
1757           This variable conditionally defines the "HAS_GETHOSTBYADDR_R"
1758           symbol, which indicates to the C program that the gethostbyaddr_r()
1759           routine is available.
1760
1761       "d_gethostbyname_r"
1762           From d_gethostbyname_r.U:
1763
1764           This variable conditionally defines the "HAS_GETHOSTBYNAME_R"
1765           symbol, which indicates to the C program that the gethostbyname_r()
1766           routine is available.
1767
1768       "d_gethostent_r"
1769           From d_gethostent_r.U:
1770
1771           This variable conditionally defines the "HAS_GETHOSTENT_R" symbol,
1772           which indicates to the C program that the gethostent_r() routine is
1773           available.
1774
1775       "d_gethostprotos"
1776           From d_gethostprotos.U:
1777
1778           This variable conditionally defines the "HAS_GETHOST_PROTOS"
1779           symbol, which indicates to the C program that <netdb.h> supplies
1780           prototypes for the various gethost*() functions.  See also
1781           netdbtype.U for probing for various netdb types.
1782
1783       "d_getitimer"
1784           From d_getitimer.U:
1785
1786           This variable conditionally defines the "HAS_GETITIMER" symbol,
1787           which indicates to the C program that the getitimer() routine is
1788           available.
1789
1790       "d_getlogin"
1791           From d_getlogin.U:
1792
1793           This variable conditionally defines the "HAS_GETLOGIN" symbol,
1794           which indicates to the C program that the getlogin() routine is
1795           available to get the login name.
1796
1797       "d_getlogin_r"
1798           From d_getlogin_r.U:
1799
1800           This variable conditionally defines the "HAS_GETLOGIN_R" symbol,
1801           which indicates to the C program that the getlogin_r() routine is
1802           available.
1803
1804       "d_getmnt"
1805           From d_getmnt.U:
1806
1807           This variable conditionally defines the "HAS_GETMNT" symbol, which
1808           indicates to the C program that the getmnt() routine is available
1809           to retrieve one or more mount info blocks by filename.
1810
1811       "d_getmntent"
1812           From d_getmntent.U:
1813
1814           This variable conditionally defines the "HAS_GETMNTENT" symbol,
1815           which indicates to the C program that the getmntent() routine is
1816           available to iterate through mounted files to get their mount info.
1817
1818       "d_getnameinfo"
1819           From d_getnameinfo.U:
1820
1821           This variable conditionally defines the "HAS_GETNAMEINFO" symbol,
1822           which indicates to the C program that the getnameinfo() function is
1823           available.
1824
1825       "d_getnbyaddr"
1826           From d_getnbyad.U:
1827
1828           This variable conditionally defines the "HAS_GETNETBYADDR" symbol,
1829           which indicates to the C program that the getnetbyaddr() routine is
1830           available to look up networks by their "IP" addresses.
1831
1832       "d_getnbyname"
1833           From d_getnbynm.U:
1834
1835           This variable conditionally defines the "HAS_GETNETBYNAME" symbol,
1836           which indicates to the C program that the getnetbyname() routine is
1837           available to look up networks by their names.
1838
1839       "d_getnent"
1840           From d_getnent.U:
1841
1842           This variable conditionally defines "HAS_GETNETENT" if getnetent()
1843           is available to look up network names in some data base or another.
1844
1845       "d_getnetbyaddr_r"
1846           From d_getnetbyaddr_r.U:
1847
1848           This variable conditionally defines the "HAS_GETNETBYADDR_R"
1849           symbol, which indicates to the C program that the getnetbyaddr_r()
1850           routine is available.
1851
1852       "d_getnetbyname_r"
1853           From d_getnetbyname_r.U:
1854
1855           This variable conditionally defines the "HAS_GETNETBYNAME_R"
1856           symbol, which indicates to the C program that the getnetbyname_r()
1857           routine is available.
1858
1859       "d_getnetent_r"
1860           From d_getnetent_r.U:
1861
1862           This variable conditionally defines the "HAS_GETNETENT_R" symbol,
1863           which indicates to the C program that the getnetent_r() routine is
1864           available.
1865
1866       "d_getnetprotos"
1867           From d_getnetprotos.U:
1868
1869           This variable conditionally defines the "HAS_GETNET_PROTOS" symbol,
1870           which indicates to the C program that <netdb.h> supplies prototypes
1871           for the various getnet*() functions.  See also netdbtype.U for
1872           probing for various netdb types.
1873
1874       "d_getpagsz"
1875           From d_getpagsz.U:
1876
1877           This variable conditionally defines "HAS_GETPAGESIZE" if
1878           getpagesize() is available to get the system page size.
1879
1880       "d_getpbyname"
1881           From d_getprotby.U:
1882
1883           This variable conditionally defines the "HAS_GETPROTOBYNAME"
1884           symbol, which indicates to the C program that the getprotobyname()
1885           routine is available to look up protocols by their name.
1886
1887       "d_getpbynumber"
1888           From d_getprotby.U:
1889
1890           This variable conditionally defines the "HAS_GETPROTOBYNUMBER"
1891           symbol, which indicates to the C program that the
1892           getprotobynumber() routine is available to look up protocols by
1893           their number.
1894
1895       "d_getpent"
1896           From d_getpent.U:
1897
1898           This variable conditionally defines "HAS_GETPROTOENT" if
1899           getprotoent() is available to look up protocols in some data base
1900           or another.
1901
1902       "d_getpgid"
1903           From d_getpgid.U:
1904
1905           This variable conditionally defines the "HAS_GETPGID" symbol, which
1906           indicates to the C program that the getpgid(pid) function is
1907           available to get the process group id.
1908
1909       "d_getpgrp"
1910           From d_getpgrp.U:
1911
1912           This variable conditionally defines "HAS_GETPGRP" if getpgrp() is
1913           available to get the current process group.
1914
1915       "d_getpgrp2"
1916           From d_getpgrp2.U:
1917
1918           This variable conditionally defines the HAS_GETPGRP2 symbol, which
1919           indicates to the C program that the getpgrp2() (as in DG/"UX")
1920           routine is available to get the current process group.
1921
1922       "d_getppid"
1923           From d_getppid.U:
1924
1925           This variable conditionally defines the "HAS_GETPPID" symbol, which
1926           indicates to the C program that the getppid() routine is available
1927           to get the parent process "ID".
1928
1929       "d_getprior"
1930           From d_getprior.U:
1931
1932           This variable conditionally defines "HAS_GETPRIORITY" if
1933           getpriority() is available to get a process's priority.
1934
1935       "d_getprotobyname_r"
1936           From d_getprotobyname_r.U:
1937
1938           This variable conditionally defines the "HAS_GETPROTOBYNAME_R"
1939           symbol, which indicates to the C program that the
1940           getprotobyname_r() routine is available.
1941
1942       "d_getprotobynumber_r"
1943           From d_getprotobynumber_r.U:
1944
1945           This variable conditionally defines the "HAS_GETPROTOBYNUMBER_R"
1946           symbol, which indicates to the C program that the
1947           getprotobynumber_r() routine is available.
1948
1949       "d_getprotoent_r"
1950           From d_getprotoent_r.U:
1951
1952           This variable conditionally defines the "HAS_GETPROTOENT_R" symbol,
1953           which indicates to the C program that the getprotoent_r() routine
1954           is available.
1955
1956       "d_getprotoprotos"
1957           From d_getprotoprotos.U:
1958
1959           This variable conditionally defines the "HAS_GETPROTO_PROTOS"
1960           symbol, which indicates to the C program that <netdb.h> supplies
1961           prototypes for the various getproto*() functions.  See also
1962           netdbtype.U for probing for various netdb types.
1963
1964       "d_getprpwnam"
1965           From d_getprpwnam.U:
1966
1967           This variable conditionally defines "HAS_GETPRPWNAM" if
1968           getprpwnam() is available to retrieve protected (shadow) password
1969           entries by name.
1970
1971       "d_getpwent"
1972           From d_getpwent.U:
1973
1974           This variable conditionally defines the "HAS_GETPWENT" symbol,
1975           which indicates to the C program that the getpwent() routine is
1976           available for sequential access of the passwd database.
1977
1978       "d_getpwent_r"
1979           From d_getpwent_r.U:
1980
1981           This variable conditionally defines the "HAS_GETPWENT_R" symbol,
1982           which indicates to the C program that the getpwent_r() routine is
1983           available.
1984
1985       "d_getpwnam_r"
1986           From d_getpwnam_r.U:
1987
1988           This variable conditionally defines the "HAS_GETPWNAM_R" symbol,
1989           which indicates to the C program that the getpwnam_r() routine is
1990           available.
1991
1992       "d_getpwuid_r"
1993           From d_getpwuid_r.U:
1994
1995           This variable conditionally defines the "HAS_GETPWUID_R" symbol,
1996           which indicates to the C program that the getpwuid_r() routine is
1997           available.
1998
1999       "d_getsbyname"
2000           From d_getsrvby.U:
2001
2002           This variable conditionally defines the "HAS_GETSERVBYNAME" symbol,
2003           which indicates to the C program that the getservbyname() routine
2004           is available to look up services by their name.
2005
2006       "d_getsbyport"
2007           From d_getsrvby.U:
2008
2009           This variable conditionally defines the "HAS_GETSERVBYPORT" symbol,
2010           which indicates to the C program that the getservbyport() routine
2011           is available to look up services by their port.
2012
2013       "d_getsent"
2014           From d_getsent.U:
2015
2016           This variable conditionally defines "HAS_GETSERVENT" if
2017           getservent() is available to look up network services in some data
2018           base or another.
2019
2020       "d_getservbyname_r"
2021           From d_getservbyname_r.U:
2022
2023           This variable conditionally defines the "HAS_GETSERVBYNAME_R"
2024           symbol, which indicates to the C program that the getservbyname_r()
2025           routine is available.
2026
2027       "d_getservbyport_r"
2028           From d_getservbyport_r.U:
2029
2030           This variable conditionally defines the "HAS_GETSERVBYPORT_R"
2031           symbol, which indicates to the C program that the getservbyport_r()
2032           routine is available.
2033
2034       "d_getservent_r"
2035           From d_getservent_r.U:
2036
2037           This variable conditionally defines the "HAS_GETSERVENT_R" symbol,
2038           which indicates to the C program that the getservent_r() routine is
2039           available.
2040
2041       "d_getservprotos"
2042           From d_getservprotos.U:
2043
2044           This variable conditionally defines the "HAS_GETSERV_PROTOS"
2045           symbol, which indicates to the C program that <netdb.h> supplies
2046           prototypes for the various getserv*() functions.  See also
2047           netdbtype.U for probing for various netdb types.
2048
2049       "d_getspnam"
2050           From d_getspnam.U:
2051
2052           This variable conditionally defines "HAS_GETSPNAM" if getspnam() is
2053           available to retrieve SysV shadow password entries by name.
2054
2055       "d_getspnam_r"
2056           From d_getspnam_r.U:
2057
2058           This variable conditionally defines the "HAS_GETSPNAM_R" symbol,
2059           which indicates to the C program that the getspnam_r() routine is
2060           available.
2061
2062       "d_gettimeod"
2063           From d_ftime.U:
2064
2065           This variable conditionally defines the "HAS_GETTIMEOFDAY" symbol,
2066           which indicates that the gettimeofday() system call exists (to
2067           obtain a sub-second accuracy clock). You should probably include
2068           <sys/resource.h>.
2069
2070       "d_gmtime64"
2071           From d_timefuncs64.U:
2072
2073           This variable conditionally defines the HAS_GMTIME64 symbol, which
2074           indicates to the C program that the gmtime64 () routine is
2075           available.
2076
2077       "d_gmtime_r"
2078           From d_gmtime_r.U:
2079
2080           This variable conditionally defines the "HAS_GMTIME_R" symbol,
2081           which indicates to the C program that the gmtime_r() routine is
2082           available.
2083
2084       "d_gnulibc"
2085           From d_gnulibc.U:
2086
2087           Defined if we're dealing with the "GNU" C Library.
2088
2089       "d_grpasswd"
2090           From i_grp.U:
2091
2092           This variable conditionally defines "GRPASSWD", which indicates
2093           that struct group in <grp.h> contains gr_passwd.
2094
2095       "d_has_C_UTF8"
2096           From d_setlocale.U:
2097
2098           This variable is set to either "true" or "false" depending on
2099           whether the compilation system supports the C.UTF-8 locale.
2100
2101       "d_hasmntopt"
2102           From d_hasmntopt.U:
2103
2104           This variable conditionally defines the "HAS_HASMNTOPT" symbol,
2105           which indicates to the C program that the hasmntopt() routine is
2106           available to query the mount options of file systems.
2107
2108       "d_htonl"
2109           From d_htonl.U:
2110
2111           This variable conditionally defines "HAS_HTONL" if htonl() and its
2112           friends are available to do network order byte swapping.
2113
2114       "d_hypot"
2115           From d_hypot.U:
2116
2117           This variable conditionally defines "HAS_HYPOT" if hypot is
2118           available for numerically stable hypotenuse function.
2119
2120       "d_ilogb"
2121           From d_ilogb.U:
2122
2123           This variable conditionally defines the "HAS_ILOGB" symbol, which
2124           indicates to the C program that the ilogb() routine is available
2125           for extracting the exponent of double x as a signed integer.
2126
2127       "d_ilogbl"
2128           From d_ilogbl.U:
2129
2130           This variable conditionally defines the "HAS_ILOGBL" symbol, which
2131           indicates to the C program that the ilogbl() routine is available
2132           for extracting the exponent of long double x as a signed integer.
2133           If scalbnl is also present we can emulate frexpl.
2134
2135       "d_inc_version_list"
2136           From inc_version_list.U:
2137
2138           This variable conditionally defines "PERL_INC_VERSION_LIST".  It is
2139           set to undef when "PERL_INC_VERSION_LIST" is empty.
2140
2141       "d_inetaton"
2142           From d_inetaton.U:
2143
2144           This variable conditionally defines the "HAS_INET_ATON" symbol,
2145           which indicates to the C program that the inet_aton() function is
2146           available to parse "IP" address "dotted-quad" strings.
2147
2148       "d_inetntop"
2149           From d_inetntop.U:
2150
2151           This variable conditionally defines the "HAS_INETNTOP" symbol,
2152           which indicates to the C program that the inet_ntop() function is
2153           available.
2154
2155       "d_inetpton"
2156           From d_inetpton.U:
2157
2158           This variable conditionally defines the "HAS_INETPTON" symbol,
2159           which indicates to the C program that the inet_pton() function is
2160           available.
2161
2162       "d_int64_t"
2163           From d_int64_t.U:
2164
2165           This symbol will be defined if the C compiler supports int64_t.
2166
2167       "d_ip_mreq"
2168           From d_socket.U:
2169
2170           This variable conditionally defines the "HAS_IP_MREQ" symbol, which
2171           indicates the availability of a struct ip_mreq.
2172
2173       "d_ip_mreq_source"
2174           From d_socket.U:
2175
2176           This variable conditionally defines the "HAS_IP_MREQ_SOURCE"
2177           symbol, which indicates the availability of a struct
2178           ip_mreq_source.
2179
2180       "d_ipv6_mreq"
2181           From d_socket.U:
2182
2183           This variable conditionally defines the HAS_IPV6_MREQ symbol, which
2184           indicates the availability of a struct ipv6_mreq.
2185
2186       "d_ipv6_mreq_source"
2187           From d_socket.U:
2188
2189           This variable conditionally defines the HAS_IPV6_MREQ_SOURCE
2190           symbol, which indicates the availability of a struct
2191           ipv6_mreq_source.
2192
2193       "d_isascii"
2194           From d_isascii.U:
2195
2196           This variable conditionally defines the "HAS_ISASCII" constant,
2197           which indicates to the C program that isascii() is available.
2198
2199       "d_isblank"
2200           From d_isblank.U:
2201
2202           This variable conditionally defines the "HAS_ISBLANK" constant,
2203           which indicates to the C program that isblank() is available.
2204
2205       "d_isfinite"
2206           From d_isfinite.U:
2207
2208           This variable conditionally defines the "HAS_ISFINITE" symbol,
2209           which indicates to the C program that the isfinite() routine is
2210           available.
2211
2212       "d_isfinitel"
2213           From d_isfinitel.U:
2214
2215           This variable conditionally defines the "HAS_ISFINITEL" symbol,
2216           which indicates to the C program that the isfinitel() routine is
2217           available.
2218
2219       "d_isinf"
2220           From d_isinf.U:
2221
2222           This variable conditionally defines the "HAS_ISINF" symbol, which
2223           indicates to the C program that the isinf() routine is available.
2224
2225       "d_isinfl"
2226           From d_isinfl.U:
2227
2228           This variable conditionally defines the "HAS_ISINFL" symbol, which
2229           indicates to the C program that the isinfl() routine is available.
2230
2231       "d_isless"
2232           From d_isless.U:
2233
2234           This variable conditionally defines the "HAS_ISLESS" symbol, which
2235           indicates to the C program that the isless() routine is available.
2236
2237       "d_isnan"
2238           From d_isnan.U:
2239
2240           This variable conditionally defines the "HAS_ISNAN" symbol, which
2241           indicates to the C program that the isnan() routine is available.
2242
2243       "d_isnanl"
2244           From d_isnanl.U:
2245
2246           This variable conditionally defines the "HAS_ISNANL" symbol, which
2247           indicates to the C program that the isnanl() routine is available.
2248
2249       "d_isnormal"
2250           From d_isnormal.U:
2251
2252           This variable conditionally defines the "HAS_ISNORMAL" symbol,
2253           which indicates to the C program that the isnormal() routine is
2254           available.
2255
2256       "d_j0"
2257           From d_j0.U:
2258
2259           This variable conditionally defines the HAS_J0 symbol, which
2260           indicates to the C program that the j0() routine is available.
2261
2262       "d_j0l"
2263           From d_j0.U:
2264
2265           This variable conditionally defines the HAS_J0L symbol, which
2266           indicates to the C program that the j0l() routine is available.
2267
2268       "d_killpg"
2269           From d_killpg.U:
2270
2271           This variable conditionally defines the "HAS_KILLPG" symbol, which
2272           indicates to the C program that the killpg() routine is available
2273           to kill process groups.
2274
2275       "d_lc_monetary_2008"
2276           From d_lc_monetary_2008.U:
2277
2278           This variable conditionally defines HAS_LC_MONETARY_2008 if libc
2279           has the international currency locale rules from "POSIX"
2280           1003.1-2008.
2281
2282       "d_lchown"
2283           From d_lchown.U:
2284
2285           This variable conditionally defines the "HAS_LCHOWN" symbol, which
2286           indicates to the C program that the lchown() routine is available
2287           to operate on a symbolic link (instead of following the link).
2288
2289       "d_ldbl_dig"
2290           From d_ldbl_dig.U:
2291
2292           This variable conditionally defines d_ldbl_dig if this system's
2293           header files provide "LDBL_DIG", which is the number of significant
2294           digits in a long double precision number.
2295
2296       "d_ldexpl"
2297           From d_longdbl.U:
2298
2299           This variable conditionally defines the "HAS_LDEXPL" symbol, which
2300           indicates to the C program that the ldexpl() routine is available.
2301
2302       "d_lgamma"
2303           From d_lgamma.U:
2304
2305           This variable conditionally defines the "HAS_LGAMMA" symbol, which
2306           indicates to the C program that the lgamma() routine is available
2307           for the log gamma function.  See also d_tgamma and d_lgamma_r.
2308
2309       "d_lgamma_r"
2310           From d_lgamma_r.U:
2311
2312           This variable conditionally defines the "HAS_LGAMMA_R" symbol,
2313           which indicates to the C program that the lgamma_r() routine is
2314           available for the log gamma function, without using the global
2315           signgam variable.
2316
2317       "d_libm_lib_version"
2318           From d_libm_lib_version.U:
2319
2320           This variable conditionally defines the "LIBM_LIB_VERSION" symbol,
2321           which indicates to the C program that math.h defines "_LIB_VERSION"
2322           being available in libm
2323
2324       "d_libname_unique"
2325           From so.U:
2326
2327           This variable is defined if the target system insists on unique
2328           basenames for shared library files. This is currently true on
2329           Android, false everywhere else we know of.  Defaults to "undef".
2330
2331       "d_link"
2332           From d_link.U:
2333
2334           This variable conditionally defines "HAS_LINK" if link() is
2335           available to create hard links.
2336
2337       "d_linkat"
2338           From d_fsat.U:
2339
2340           This variable conditionally defines the "HAS_LINKAT" symbol, which
2341           indicates the "POSIX" linkat() function is available.
2342
2343       "d_llrint"
2344           From d_llrint.U:
2345
2346           This variable conditionally defines the "HAS_LLRINT" symbol, which
2347           indicates to the C program that the llrint() routine is available
2348           to return the long long value closest to a double (according to the
2349           current rounding mode).
2350
2351       "d_llrintl"
2352           From d_llrintl.U:
2353
2354           This variable conditionally defines the "HAS_LLRINTL" symbol, which
2355           indicates to the C program that the llrintl() routine is available
2356           to return the long long value closest to a long double (according
2357           to the current rounding mode).
2358
2359       "d_llround"
2360           From d_llround.U:
2361
2362           This variable conditionally defines the "HAS_LLROUND" symbol, which
2363           indicates to the C program that the llround() routine is available
2364           to return the long long value nearest to x.
2365
2366       "d_llroundl"
2367           From d_llroundl.U:
2368
2369           This variable conditionally defines the "HAS_LLROUNDL" symbol,
2370           which indicates to the C program that the llroundl() routine is
2371           available to return the long long value nearest to x away from
2372           zero.
2373
2374       "d_localeconv_l"
2375           From d_localeconv_l.U:
2376
2377           This variable conditionally defines the "HAS_LOCALECONV_L" symbol,
2378           which indicates to the C program that the localeconv_l() routine is
2379           available.
2380
2381       "d_localtime64"
2382           From d_timefuncs64.U:
2383
2384           This variable conditionally defines the HAS_LOCALTIME64 symbol,
2385           which indicates to the C program that the localtime64 () routine is
2386           available.
2387
2388       "d_localtime_r"
2389           From d_localtime_r.U:
2390
2391           This variable conditionally defines the "HAS_LOCALTIME_R" symbol,
2392           which indicates to the C program that the localtime_r() routine is
2393           available.
2394
2395       "d_localtime_r_needs_tzset"
2396           From d_localtime_r.U:
2397
2398           This variable conditionally defines the "LOCALTIME_R_NEEDS_TZSET"
2399           symbol, which makes us call tzset before localtime_r()
2400
2401       "d_locconv"
2402           From d_locconv.U:
2403
2404           This variable conditionally defines "HAS_LOCALECONV" if
2405           localeconv() is available for numeric and monetary formatting
2406           conventions.
2407
2408       "d_lockf"
2409           From d_lockf.U:
2410
2411           This variable conditionally defines "HAS_LOCKF" if lockf() is
2412           available to do file locking.
2413
2414       "d_log1p"
2415           From d_log1p.U:
2416
2417           This variable conditionally defines the HAS_LOG1P symbol, which
2418           indicates to the C program that the logp1() routine is available to
2419           compute log(1 + x) for values of x close to zero.
2420
2421       "d_log2"
2422           From d_log2.U:
2423
2424           This variable conditionally defines the HAS_LOG2 symbol, which
2425           indicates to the C program that the log2() routine is available to
2426           compute log base two.
2427
2428       "d_logb"
2429           From d_logb.U:
2430
2431           This variable conditionally defines the "HAS_LOGB" symbol, which
2432           indicates to the C program that the logb() routine is available to
2433           extract the exponent of x.
2434
2435       "d_long_double_style_ieee"
2436           From d_longdbl.U:
2437
2438           This variable conditionally defines "LONG_DOUBLE_STYLE_IEEE" if the
2439           long double is any of the "IEEE" 754 style long doubles:
2440           "LONG_DOUBLE_STYLE_IEEE_STD", "LONG_DOUBLE_STYLE_IEEE_EXTENDED",
2441           "LONG_DOUBLE_STYLE_IEEE_DOUBLEDOUBLE".
2442
2443       "d_long_double_style_ieee_doubledouble"
2444           From d_longdbl.U:
2445
2446           This variable conditionally defines
2447           "LONG_DOUBLE_STYLE_IEEE_DOUBLEDOUBLE" if the long double is the
2448           128-bit "IEEE" 754 double-double.
2449
2450       "d_long_double_style_ieee_extended"
2451           From d_longdbl.U:
2452
2453           This variable conditionally defines
2454           "LONG_DOUBLE_STYLE_IEEE_EXTENDED" if the long double is the 80-bit
2455           "IEEE" 754 extended precision.  Note that despite the "extended"
2456           this is less than the "std", since this is an extension of the
2457           double precision.
2458
2459       "d_long_double_style_ieee_std"
2460           From d_longdbl.U:
2461
2462           This variable conditionally defines "LONG_DOUBLE_STYLE_IEEE_STD" if
2463           the long double is the 128-bit "IEEE" 754.
2464
2465       "d_long_double_style_vax"
2466           From d_longdbl.U:
2467
2468           This variable conditionally defines "LONG_DOUBLE_STYLE_VAX" if the
2469           long double is the 128-bit "VAX" format H.
2470
2471       "d_longdbl"
2472           From d_longdbl.U:
2473
2474           This variable conditionally defines "HAS_LONG_DOUBLE" if the long
2475           double type is supported.
2476
2477       "d_longlong"
2478           From d_longlong.U:
2479
2480           This variable conditionally defines "HAS_LONG_LONG" if the long
2481           long type is supported.
2482
2483       "d_lrint"
2484           From d_lrint.U:
2485
2486           This variable conditionally defines the "HAS_LRINT" symbol, which
2487           indicates to the C program that the lrint() routine is available to
2488           return the integral value closest to a double (according to the
2489           current rounding mode).
2490
2491       "d_lrintl"
2492           From d_lrintl.U:
2493
2494           This variable conditionally defines the "HAS_LRINTL" symbol, which
2495           indicates to the C program that the lrintl() routine is available
2496           to return the integral value closest to a long double (according to
2497           the current rounding mode).
2498
2499       "d_lround"
2500           From d_lround.U:
2501
2502           This variable conditionally defines the "HAS_LROUND" symbol, which
2503           indicates to the C program that the lround() routine is available
2504           to return the integral value nearest to x.
2505
2506       "d_lroundl"
2507           From d_lroundl.U:
2508
2509           This variable conditionally defines the "HAS_LROUNDL" symbol, which
2510           indicates to the C program that the lroundl() routine is available
2511           to return the integral value nearest to x away from zero.
2512
2513       "d_lseekproto"
2514           From d_lseekproto.U:
2515
2516           This variable conditionally defines the "HAS_LSEEK_PROTO" symbol,
2517           which indicates to the C program that the system provides a
2518           prototype for the lseek() function.  Otherwise, it is up to the
2519           program to supply one.
2520
2521       "d_lstat"
2522           From d_lstat.U:
2523
2524           This variable conditionally defines "HAS_LSTAT" if lstat() is
2525           available to do file stats on symbolic links.
2526
2527       "d_madvise"
2528           From d_madvise.U:
2529
2530           This variable conditionally defines "HAS_MADVISE" if madvise() is
2531           available to map a file into memory.
2532
2533       "d_malloc_good_size"
2534           From d_malloc_size.U:
2535
2536           This symbol, if defined, indicates that the malloc_good_size
2537           routine is available for use.
2538
2539       "d_malloc_size"
2540           From d_malloc_size.U:
2541
2542           This symbol, if defined, indicates that the malloc_size routine is
2543           available for use.
2544
2545       "d_malloc_usable_size"
2546           From d_malloc_size.U:
2547
2548           This symbol, if defined, indicates that the malloc_usable_size
2549           routine is available for use.
2550
2551       "d_mblen"
2552           From d_mblen.U:
2553
2554           This variable conditionally defines the "HAS_MBLEN" symbol, which
2555           indicates to the C program that the mblen() routine is available to
2556           find the number of bytes in a multibyte character.
2557
2558       "d_mbrlen"
2559           From d_mbrlen.U:
2560
2561           This variable conditionally defines the "HAS_MBRLEN" symbol if the
2562           mbrlen() routine is available to be used to get the length of
2563           multi-byte character strings.
2564
2565       "d_mbrtowc"
2566           From d_mbrtowc.U:
2567
2568           This variable conditionally defines the "HAS_MBRTOWC" symbol if the
2569           mbrtowc() routine is available to be used to convert a multi-byte
2570           character into a wide character.
2571
2572       "d_mbstowcs"
2573           From d_mbstowcs.U:
2574
2575           This variable conditionally defines the "HAS_MBSTOWCS" symbol,
2576           which indicates to the C program that the mbstowcs() routine is
2577           available to convert a multibyte string into a wide character
2578           string.
2579
2580       "d_mbtowc"
2581           From d_mbtowc.U:
2582
2583           This variable conditionally defines the "HAS_MBTOWC" symbol, which
2584           indicates to the C program that the mbtowc() routine is available
2585           to convert multibyte to a wide character.
2586
2587       "d_memmem"
2588           From d_memmem.U:
2589
2590           This variable conditionally defines the "HAS_MEMMEM" symbol, which
2591           indicates to the C program that the memmem() routine is available
2592           to return a pointer to the start of the first occurrence of a
2593           substring in a memory area (or "NULL" if not found).
2594
2595       "d_memrchr"
2596           From d_memrchr.U:
2597
2598           This variable conditionally defines the "HAS_MEMRCHR" symbol, which
2599           indicates to the C program that the memrchr() routine is available
2600           to return a pointer to the last occurrence of a byte in a memory
2601           area (or "NULL" if not found).
2602
2603       "d_mkdir"
2604           From d_mkdir.U:
2605
2606           This variable conditionally defines the "HAS_MKDIR" symbol, which
2607           indicates to the C program that the mkdir() routine is available to
2608           create directories..
2609
2610       "d_mkdtemp"
2611           From d_mkdtemp.U:
2612
2613           This variable conditionally defines the "HAS_MKDTEMP" symbol, which
2614           indicates to the C program that the mkdtemp() routine is available
2615           to exclusively create a uniquely named temporary directory.
2616
2617       "d_mkfifo"
2618           From d_mkfifo.U:
2619
2620           This variable conditionally defines the "HAS_MKFIFO" symbol, which
2621           indicates to the C program that the mkfifo() routine is available.
2622
2623       "d_mkostemp"
2624           From d_mkostemp.U:
2625
2626           This variable conditionally defines "HAS_MKOSTEMP" if mkostemp() is
2627           available to exclusively create and open a uniquely named (with a
2628           suffix) temporary file.
2629
2630       "d_mkstemp"
2631           From d_mkstemp.U:
2632
2633           This variable conditionally defines the "HAS_MKSTEMP" symbol, which
2634           indicates to the C program that the mkstemp() routine is available
2635           to exclusively create and open a uniquely named temporary file.
2636
2637       "d_mkstemps"
2638           From d_mkstemps.U:
2639
2640           This variable conditionally defines the "HAS_MKSTEMPS" symbol,
2641           which indicates to the C program that the mkstemps() routine is
2642           available to exclusively create and open a uniquely named (with a
2643           suffix) temporary file.
2644
2645       "d_mktime"
2646           From d_mktime.U:
2647
2648           This variable conditionally defines the "HAS_MKTIME" symbol, which
2649           indicates to the C program that the mktime() routine is available.
2650
2651       "d_mktime64"
2652           From d_timefuncs64.U:
2653
2654           This variable conditionally defines the HAS_MKTIME64 symbol, which
2655           indicates to the C program that the mktime64 () routine is
2656           available.
2657
2658       "d_mmap"
2659           From d_mmap.U:
2660
2661           This variable conditionally defines "HAS_MMAP" if mmap() is
2662           available to map a file into memory.
2663
2664       "d_modfl"
2665           From d_modfl.U:
2666
2667           This variable conditionally defines the "HAS_MODFL" symbol, which
2668           indicates to the C program that the modfl() routine is available.
2669
2670       "d_modflproto"
2671           From d_modfl.U:
2672
2673           This symbol, if defined, indicates that the system provides a
2674           prototype for the modfl() function.  Otherwise, it is up to the
2675           program to supply one.  C99 says it should be long double
2676           modfl(long double, long double *);
2677
2678       "d_mprotect"
2679           From d_mprotect.U:
2680
2681           This variable conditionally defines "HAS_MPROTECT" if mprotect() is
2682           available to modify the access protection of a memory mapped file.
2683
2684       "d_msg"
2685           From d_msg.U:
2686
2687           This variable conditionally defines the "HAS_MSG" symbol, which
2688           indicates that the entire msg*(2) library is present.
2689
2690       "d_msg_ctrunc"
2691           From d_socket.U:
2692
2693           This variable conditionally defines the "HAS_MSG_CTRUNC" symbol,
2694           which indicates that the "MSG_CTRUNC" is available.  #ifdef is not
2695           enough because it may be an enum, glibc has been known to do this.
2696
2697       "d_msg_dontroute"
2698           From d_socket.U:
2699
2700           This variable conditionally defines the "HAS_MSG_DONTROUTE" symbol,
2701           which indicates that the "MSG_DONTROUTE" is available.  #ifdef is
2702           not enough because it may be an enum, glibc has been known to do
2703           this.
2704
2705       "d_msg_oob"
2706           From d_socket.U:
2707
2708           This variable conditionally defines the "HAS_MSG_OOB" symbol, which
2709           indicates that the "MSG_OOB" is available.  #ifdef is not enough
2710           because it may be an enum, glibc has been known to do this.
2711
2712       "d_msg_peek"
2713           From d_socket.U:
2714
2715           This variable conditionally defines the "HAS_MSG_PEEK" symbol,
2716           which indicates that the "MSG_PEEK" is available.  #ifdef is not
2717           enough because it may be an enum, glibc has been known to do this.
2718
2719       "d_msg_proxy"
2720           From d_socket.U:
2721
2722           This variable conditionally defines the "HAS_MSG_PROXY" symbol,
2723           which indicates that the "MSG_PROXY" is available.  #ifdef is not
2724           enough because it may be an enum, glibc has been known to do this.
2725
2726       "d_msgctl"
2727           From d_msgctl.U:
2728
2729           This variable conditionally defines the "HAS_MSGCTL" symbol, which
2730           indicates to the C program that the msgctl() routine is available.
2731
2732       "d_msgget"
2733           From d_msgget.U:
2734
2735           This variable conditionally defines the "HAS_MSGGET" symbol, which
2736           indicates to the C program that the msgget() routine is available.
2737
2738       "d_msghdr_s"
2739           From d_msghdr_s.U:
2740
2741           This variable conditionally defines the "HAS_STRUCT_MSGHDR" symbol,
2742           which indicates that the struct msghdr is supported.
2743
2744       "d_msgrcv"
2745           From d_msgrcv.U:
2746
2747           This variable conditionally defines the "HAS_MSGRCV" symbol, which
2748           indicates to the C program that the msgrcv() routine is available.
2749
2750       "d_msgsnd"
2751           From d_msgsnd.U:
2752
2753           This variable conditionally defines the "HAS_MSGSND" symbol, which
2754           indicates to the C program that the msgsnd() routine is available.
2755
2756       "d_msync"
2757           From d_msync.U:
2758
2759           This variable conditionally defines "HAS_MSYNC" if msync() is
2760           available to synchronize a mapped file.
2761
2762       "d_munmap"
2763           From d_munmap.U:
2764
2765           This variable conditionally defines "HAS_MUNMAP" if munmap() is
2766           available to unmap a region mapped by mmap().
2767
2768       "d_mymalloc"
2769           From mallocsrc.U:
2770
2771           This variable conditionally defines "MYMALLOC" in case other parts
2772           of the source want to take special action if "MYMALLOC" is used.
2773           This may include different sorts of profiling or error detection.
2774
2775       "d_nan"
2776           From d_nan.U:
2777
2778           This variable conditionally defines "HAS_NAN" if nan() is available
2779           to generate NaN.
2780
2781       "d_nanosleep"
2782           From d_nanosleep.U:
2783
2784           This variable conditionally defines "HAS_NANOSLEEP" if nanosleep()
2785           is available to sleep with 1E-9 sec accuracy.
2786
2787       "d_ndbm"
2788           From i_ndbm.U:
2789
2790           This variable conditionally defines the "HAS_NDBM" symbol, which
2791           indicates that both the ndbm.h include file and an appropriate ndbm
2792           library exist.  Consult the different i_*ndbm variables to find out
2793           the actual include location.  Sometimes, a system has the header
2794           file but not the library.  This variable will only be set if the
2795           system has both.
2796
2797       "d_ndbm_h_uses_prototypes"
2798           From i_ndbm.U:
2799
2800           This variable conditionally defines the "NDBM_H_USES_PROTOTYPES"
2801           symbol, which indicates that the ndbm.h include file uses real
2802           "ANSI" C prototypes instead of K&R style function declarations. K&R
2803           style declarations are unsupported in C++, so the include file
2804           requires special handling when using a C++ compiler and this
2805           variable is undefined. Consult the different
2806           d_*ndbm_h_uses_prototypes variables to get the same information for
2807           alternative ndbm.h include files.
2808
2809       "d_nearbyint"
2810           From d_nearbyint.U:
2811
2812           This variable conditionally defines "HAS_NEARBYINT" if nearbyint()
2813           is available to return the integral value closest to (according to
2814           the current rounding mode) to x.
2815
2816       "d_newlocale"
2817           From d_newlocale.U:
2818
2819           This variable conditionally defines the "HAS_NEWLOCALE" symbol,
2820           which indicates to the C program that the newlocale() routine is
2821           available to return a new locale object or modify an existing
2822           locale object.
2823
2824       "d_nextafter"
2825           From d_nextafter.U:
2826
2827           This variable conditionally defines "HAS_NEXTAFTER" if nextafter()
2828           is available to return the next machine representable double from x
2829           in direction y.
2830
2831       "d_nexttoward"
2832           From d_nexttoward.U:
2833
2834           This variable conditionally defines "HAS_NEXTTOWARD" if
2835           nexttoward() is available to return the next machine representable
2836           long double from x in direction y.
2837
2838       "d_nice"
2839           From d_nice.U:
2840
2841           This variable conditionally defines the "HAS_NICE" symbol, which
2842           indicates to the C program that the nice() routine is available.
2843
2844       "d_nl_langinfo"
2845           From d_nl_langinfo.U:
2846
2847           This variable conditionally defines the "HAS_NL_LANGINFO" symbol,
2848           which indicates to the C program that the nl_langinfo() routine is
2849           available.
2850
2851       "d_nl_langinfo_l"
2852           From d_nl_langinfo_l.U:
2853
2854           This variable contains the eventual value of the
2855           "HAS_NL_LANGINFO_L" symbol, which indicates if the nl_langinfo_l()
2856           function exists.
2857
2858       "d_non_int_bitfields"
2859           From d_bitfield.U:
2860
2861           This variable conditionally defines "HAS_NON_INT_BITFIELDS" which
2862           indicates that the C compiler accepts struct bitfields of sizes
2863           that aren't "int" or "unsigned int"
2864
2865       "d_nv_preserves_uv"
2866           From perlxv.U:
2867
2868           This variable indicates whether a variable of type nvtype can
2869           preserve all the bits a variable of type uvtype.
2870
2871       "d_nv_zero_is_allbits_zero"
2872           From perlxv.U:
2873
2874           This variable indicates whether a variable of type nvtype stores
2875           0.0 in memory as all bits zero.
2876
2877       "d_off64_t"
2878           From d_off64_t.U:
2879
2880           This symbol will be defined if the C compiler supports off64_t.
2881
2882       "d_old_pthread_create_joinable"
2883           From d_pthrattrj.U:
2884
2885           This variable conditionally defines pthread_create_joinable.  undef
2886           if pthread.h defines "PTHREAD_CREATE_JOINABLE".
2887
2888       "d_oldpthreads"
2889           From usethreads.U:
2890
2891           This variable conditionally defines the "OLD_PTHREADS_API" symbol,
2892           and indicates that Perl should be built to use the old draft
2893           "POSIX" threads "API".  This is only potentially meaningful if
2894           usethreads is set.
2895
2896       "d_oldsock"
2897           From d_socket.U:
2898
2899           This variable conditionally defines the "OLDSOCKET" symbol, which
2900           indicates that the "BSD" socket interface is based on 4.1c and not
2901           4.2.
2902
2903       "d_open3"
2904           From d_open3.U:
2905
2906           This variable conditionally defines the HAS_OPEN3 manifest
2907           constant, which indicates to the C program that the 3 argument
2908           version of the open(2) function is available.
2909
2910       "d_openat"
2911           From d_fsat.U:
2912
2913           This variable conditionally defines the "HAS_OPENAT" symbol, which
2914           indicates the "POSIX" openat() function is available.
2915
2916       "d_pathconf"
2917           From d_pathconf.U:
2918
2919           This variable conditionally defines the "HAS_PATHCONF" symbol,
2920           which indicates to the C program that the pathconf() routine is
2921           available to determine file-system related limits and options
2922           associated with a given filename.
2923
2924       "d_pause"
2925           From d_pause.U:
2926
2927           This variable conditionally defines the "HAS_PAUSE" symbol, which
2928           indicates to the C program that the pause() routine is available to
2929           suspend a process until a signal is received.
2930
2931       "d_perl_otherlibdirs"
2932           From otherlibdirs.U:
2933
2934           This variable conditionally defines "PERL_OTHERLIBDIRS", which
2935           contains a colon-separated set of paths for the perl binary to
2936           include in @"INC".  See also otherlibdirs.
2937
2938       "d_phostname"
2939           From d_gethname.U:
2940
2941           This variable conditionally defines the "HAS_PHOSTNAME" symbol,
2942           which contains the shell command which, when fed to popen(), may be
2943           used to derive the host name.
2944
2945       "d_pipe"
2946           From d_pipe.U:
2947
2948           This variable conditionally defines the "HAS_PIPE" symbol, which
2949           indicates to the C program that the pipe() routine is available to
2950           create an inter-process channel.
2951
2952       "d_pipe2"
2953           From d_pipe2.U:
2954
2955           This variable conditionally defines the HAS_PIPE2 symbol, which
2956           indicates to the C program that the pipe2() routine is available to
2957           create an inter-process channel.
2958
2959       "d_poll"
2960           From d_poll.U:
2961
2962           This variable conditionally defines the "HAS_POLL" symbol, which
2963           indicates to the C program that the poll() routine is available to
2964           poll active file descriptors.
2965
2966       "d_portable"
2967           From d_portable.U:
2968
2969           This variable conditionally defines the "PORTABLE" symbol, which
2970           indicates to the C program that it should not assume that it is
2971           running on the machine it was compiled on.
2972
2973       "d_prctl"
2974           From d_prctl.U:
2975
2976           This variable conditionally defines the "HAS_PRCTL" symbol, which
2977           indicates to the C program that the prctl() routine is available.
2978           Note that there are at least two prctl variants: Linux and Irix.
2979           While they are somewhat similar, they are incompatible.
2980
2981       "d_prctl_set_name"
2982           From d_prctl.U:
2983
2984           This variable conditionally defines the "HAS_PRCTL_SET_NAME"
2985           symbol, which indicates to the C program that the prctl() routine
2986           supports the "PR_SET_NAME" option.
2987
2988       "d_PRId64"
2989           From quadfio.U:
2990
2991           This variable conditionally defines the PERL_PRId64 symbol, which
2992           indicates that stdio has a symbol to print 64-bit decimal numbers.
2993
2994       "d_PRIeldbl"
2995           From longdblfio.U:
2996
2997           This variable conditionally defines the PERL_PRIfldbl symbol, which
2998           indicates that stdio has a symbol to print long doubles.
2999
3000       "d_PRIEUldbl"
3001           From longdblfio.U:
3002
3003           This variable conditionally defines the PERL_PRIfldbl symbol, which
3004           indicates that stdio has a symbol to print long doubles.  The "U"
3005           in the name is to separate this from d_PRIeldbl so that even case-
3006           blind systems can see the difference.
3007
3008       "d_PRIfldbl"
3009           From longdblfio.U:
3010
3011           This variable conditionally defines the PERL_PRIfldbl symbol, which
3012           indicates that stdio has a symbol to print long doubles.
3013
3014       "d_PRIFUldbl"
3015           From longdblfio.U:
3016
3017           This variable conditionally defines the PERL_PRIfldbl symbol, which
3018           indicates that stdio has a symbol to print long doubles.  The "U"
3019           in the name is to separate this from d_PRIfldbl so that even case-
3020           blind systems can see the difference.
3021
3022       "d_PRIgldbl"
3023           From longdblfio.U:
3024
3025           This variable conditionally defines the PERL_PRIfldbl symbol, which
3026           indicates that stdio has a symbol to print long doubles.
3027
3028       "d_PRIGUldbl"
3029           From longdblfio.U:
3030
3031           This variable conditionally defines the PERL_PRIfldbl symbol, which
3032           indicates that stdio has a symbol to print long doubles.  The "U"
3033           in the name is to separate this from d_PRIgldbl so that even case-
3034           blind systems can see the difference.
3035
3036       "d_PRIi64"
3037           From quadfio.U:
3038
3039           This variable conditionally defines the PERL_PRIi64 symbol, which
3040           indicates that stdio has a symbol to print 64-bit decimal numbers.
3041
3042       "d_printf_format_null"
3043           From d_attribut.U:
3044
3045           This variable conditionally defines "PRINTF_FORMAT_NULL_OK", which
3046           indicates the C compiler allows printf-like formats to be null.
3047
3048       "d_PRIo64"
3049           From quadfio.U:
3050
3051           This variable conditionally defines the PERL_PRIo64 symbol, which
3052           indicates that stdio has a symbol to print 64-bit octal numbers.
3053
3054       "d_PRIu64"
3055           From quadfio.U:
3056
3057           This variable conditionally defines the PERL_PRIu64 symbol, which
3058           indicates that stdio has a symbol to print 64-bit unsigned decimal
3059           numbers.
3060
3061       "d_PRIx64"
3062           From quadfio.U:
3063
3064           This variable conditionally defines the PERL_PRIx64 symbol, which
3065           indicates that stdio has a symbol to print 64-bit hexadecimal
3066           numbers.
3067
3068       "d_PRIXU64"
3069           From quadfio.U:
3070
3071           This variable conditionally defines the PERL_PRIXU64 symbol, which
3072           indicates that stdio has a symbol to print 64-bit hExADECimAl
3073           numbers.  The "U" in the name is to separate this from d_PRIx64 so
3074           that even case-blind systems can see the difference.
3075
3076       "d_procselfexe"
3077           From d_procselfexe.U:
3078
3079           Defined if $procselfexe is symlink to the absolute pathname of the
3080           executing program.
3081
3082       "d_pseudofork"
3083           From d_vfork.U:
3084
3085           This variable conditionally defines the "HAS_PSEUDOFORK" symbol,
3086           which indicates that an emulation of the fork routine is available.
3087
3088       "d_pthread_atfork"
3089           From d_pthread_atfork.U:
3090
3091           This variable conditionally defines the "HAS_PTHREAD_ATFORK"
3092           symbol, which indicates to the C program that the pthread_atfork()
3093           routine is available.
3094
3095       "d_pthread_attr_setscope"
3096           From d_pthread_attr_ss.U:
3097
3098           This variable conditionally defines "HAS_PTHREAD_ATTR_SETSCOPE" if
3099           pthread_attr_setscope() is available to set the contention scope
3100           attribute of a thread attribute object.
3101
3102       "d_pthread_yield"
3103           From d_pthread_y.U:
3104
3105           This variable conditionally defines the "HAS_PTHREAD_YIELD" symbol
3106           if the pthread_yield routine is available to yield the execution of
3107           the current thread.
3108
3109       "d_ptrdiff_t"
3110           From d_ptrdiff_t.U:
3111
3112           This symbol will be defined if the C compiler supports ptrdiff_t.
3113
3114       "d_pwage"
3115           From i_pwd.U:
3116
3117           This variable conditionally defines "PWAGE", which indicates that
3118           struct passwd contains pw_age.
3119
3120       "d_pwchange"
3121           From i_pwd.U:
3122
3123           This variable conditionally defines "PWCHANGE", which indicates
3124           that struct passwd contains pw_change.
3125
3126       "d_pwclass"
3127           From i_pwd.U:
3128
3129           This variable conditionally defines "PWCLASS", which indicates that
3130           struct passwd contains pw_class.
3131
3132       "d_pwcomment"
3133           From i_pwd.U:
3134
3135           This variable conditionally defines "PWCOMMENT", which indicates
3136           that struct passwd contains pw_comment.
3137
3138       "d_pwexpire"
3139           From i_pwd.U:
3140
3141           This variable conditionally defines "PWEXPIRE", which indicates
3142           that struct passwd contains pw_expire.
3143
3144       "d_pwgecos"
3145           From i_pwd.U:
3146
3147           This variable conditionally defines "PWGECOS", which indicates that
3148           struct passwd contains pw_gecos.
3149
3150       "d_pwpasswd"
3151           From i_pwd.U:
3152
3153           This variable conditionally defines "PWPASSWD", which indicates
3154           that struct passwd contains pw_passwd.
3155
3156       "d_pwquota"
3157           From i_pwd.U:
3158
3159           This variable conditionally defines "PWQUOTA", which indicates that
3160           struct passwd contains pw_quota.
3161
3162       "d_qgcvt"
3163           From d_qgcvt.U:
3164
3165           This variable conditionally defines the "HAS_QGCVT" symbol, which
3166           indicates to the C program that the qgcvt() routine is available.
3167
3168       "d_quad"
3169           From quadtype.U:
3170
3171           This variable, if defined, tells that there's a 64-bit integer
3172           type, quadtype.
3173
3174       "d_querylocale"
3175           From d_newlocale.U:
3176
3177           This variable conditionally defines the "HAS_QUERYLOCALE" symbol,
3178           which indicates to the C program that the querylocale() routine is
3179           available to return the name of the locale for a category mask.
3180
3181       "d_random_r"
3182           From d_random_r.U:
3183
3184           This variable conditionally defines the "HAS_RANDOM_R" symbol,
3185           which indicates to the C program that the random_r() routine is
3186           available.
3187
3188       "d_re_comp"
3189           From d_regcmp.U:
3190
3191           This variable conditionally defines the "HAS_RECOMP" symbol, which
3192           indicates to the C program that the re_comp() routine is available
3193           for regular pattern matching (usually on "BSD"). If so, it is
3194           likely that re_exec() exists.
3195
3196       "d_readdir"
3197           From d_readdir.U:
3198
3199           This variable conditionally defines "HAS_READDIR" if readdir() is
3200           available to read directory entries.
3201
3202       "d_readdir64_r"
3203           From d_readdir64_r.U:
3204
3205           This variable conditionally defines the HAS_READDIR64_R symbol,
3206           which indicates to the C program that the readdir64_r() routine is
3207           available.
3208
3209       "d_readdir_r"
3210           From d_readdir_r.U:
3211
3212           This variable conditionally defines the "HAS_READDIR_R" symbol,
3213           which indicates to the C program that the readdir_r() routine is
3214           available.
3215
3216       "d_readlink"
3217           From d_readlink.U:
3218
3219           This variable conditionally defines the "HAS_READLINK" symbol,
3220           which indicates to the C program that the readlink() routine is
3221           available to read the value of a symbolic link.
3222
3223       "d_readv"
3224           From d_readv.U:
3225
3226           This variable conditionally defines the "HAS_READV" symbol, which
3227           indicates to the C program that the readv() routine is available.
3228
3229       "d_recvmsg"
3230           From d_recvmsg.U:
3231
3232           This variable conditionally defines the "HAS_RECVMSG" symbol, which
3233           indicates to the C program that the recvmsg() routine is available.
3234
3235       "d_regcmp"
3236           From d_regcmp.U:
3237
3238           This variable conditionally defines the "HAS_REGCMP" symbol, which
3239           indicates to the C program that the regcmp() routine is available
3240           for regular pattern matching (usually on System V).
3241
3242       "d_regcomp"
3243           From d_regcmp.U:
3244
3245           This variable conditionally defines the "HAS_REGCOMP" symbol, which
3246           indicates to the C program that the regcomp() routine is available
3247           for regular pattern matching (usually on POSIX.2 conforming
3248           systems).
3249
3250       "d_remainder"
3251           From d_remainder.U:
3252
3253           This variable conditionally defines the "HAS_REMAINDER" symbol,
3254           which indicates to the C program that the remainder() routine is
3255           available.
3256
3257       "d_remquo"
3258           From d_remquo.U:
3259
3260           This variable conditionally defines the "HAS_REMQUO" symbol, which
3261           indicates to the C program that the remquo() routine is available.
3262
3263       "d_rename"
3264           From d_rename.U:
3265
3266           This variable conditionally defines the "HAS_RENAME" symbol, which
3267           indicates to the C program that the rename() routine is available
3268           to rename files.
3269
3270       "d_renameat"
3271           From d_fsat.U:
3272
3273           This variable conditionally defines the "HAS_RENAMEAT" symbol,
3274           which indicates the "POSIX" renameat() function is available.
3275
3276       "d_rewinddir"
3277           From d_readdir.U:
3278
3279           This variable conditionally defines "HAS_REWINDDIR" if rewinddir()
3280           is available.
3281
3282       "d_rint"
3283           From d_rint.U:
3284
3285           This variable conditionally defines the "HAS_RINT" symbol, which
3286           indicates to the C program that the rint() routine is available.
3287
3288       "d_rmdir"
3289           From d_rmdir.U:
3290
3291           This variable conditionally defines "HAS_RMDIR" if rmdir() is
3292           available to remove directories.
3293
3294       "d_round"
3295           From d_round.U:
3296
3297           This variable conditionally defines the "HAS_ROUND" symbol, which
3298           indicates to the C program that the round() routine is available.
3299
3300       "d_sbrkproto"
3301           From d_sbrkproto.U:
3302
3303           This variable conditionally defines the "HAS_SBRK_PROTO" symbol,
3304           which indicates to the C program that the system provides a
3305           prototype for the sbrk() function.  Otherwise, it is up to the
3306           program to supply one.
3307
3308       "d_scalbn"
3309           From d_scalbn.U:
3310
3311           This variable conditionally defines the "HAS_SCALBN" symbol, which
3312           indicates to the C program that the scalbn() routine is available.
3313
3314       "d_scalbnl"
3315           From d_scalbnl.U:
3316
3317           This variable conditionally defines the "HAS_SCALBNL" symbol, which
3318           indicates to the C program that the scalbnl() routine is available.
3319           If ilogbl is also present we can emulate frexpl.
3320
3321       "d_sched_yield"
3322           From d_pthread_y.U:
3323
3324           This variable conditionally defines the "HAS_SCHED_YIELD" symbol if
3325           the sched_yield routine is available to yield the execution of the
3326           current thread.
3327
3328       "d_scm_rights"
3329           From d_socket.U:
3330
3331           This variable conditionally defines the "HAS_SCM_RIGHTS" symbol,
3332           which indicates that the "SCM_RIGHTS" is available.  #ifdef is not
3333           enough because it may be an enum, glibc has been known to do this.
3334
3335       "d_SCNfldbl"
3336           From longdblfio.U:
3337
3338           This variable conditionally defines the PERL_PRIfldbl symbol, which
3339           indicates that stdio has a symbol to scan long doubles.
3340
3341       "d_seekdir"
3342           From d_readdir.U:
3343
3344           This variable conditionally defines "HAS_SEEKDIR" if seekdir() is
3345           available.
3346
3347       "d_select"
3348           From d_select.U:
3349
3350           This variable conditionally defines "HAS_SELECT" if select() is
3351           available to select active file descriptors. A <sys/time.h>
3352           inclusion may be necessary for the timeout field.
3353
3354       "d_sem"
3355           From d_sem.U:
3356
3357           This variable conditionally defines the "HAS_SEM" symbol, which
3358           indicates that the entire sem*(2) library is present.
3359
3360       "d_semctl"
3361           From d_semctl.U:
3362
3363           This variable conditionally defines the "HAS_SEMCTL" symbol, which
3364           indicates to the C program that the semctl() routine is available.
3365
3366       "d_semctl_semid_ds"
3367           From d_union_semun.U:
3368
3369           This variable conditionally defines "USE_SEMCTL_SEMID_DS", which
3370           indicates that struct semid_ds * is to be used for semctl
3371           "IPC_STAT".
3372
3373       "d_semctl_semun"
3374           From d_union_semun.U:
3375
3376           This variable conditionally defines "USE_SEMCTL_SEMUN", which
3377           indicates that union semun is to be used for semctl "IPC_STAT".
3378
3379       "d_semget"
3380           From d_semget.U:
3381
3382           This variable conditionally defines the "HAS_SEMGET" symbol, which
3383           indicates to the C program that the semget() routine is available.
3384
3385       "d_semop"
3386           From d_semop.U:
3387
3388           This variable conditionally defines the "HAS_SEMOP" symbol, which
3389           indicates to the C program that the semop() routine is available.
3390
3391       "d_sendmsg"
3392           From d_sendmsg.U:
3393
3394           This variable conditionally defines the "HAS_SENDMSG" symbol, which
3395           indicates to the C program that the sendmsg() routine is available.
3396
3397       "d_setegid"
3398           From d_setegid.U:
3399
3400           This variable conditionally defines the "HAS_SETEGID" symbol, which
3401           indicates to the C program that the setegid() routine is available
3402           to change the effective gid of the current program.
3403
3404       "d_seteuid"
3405           From d_seteuid.U:
3406
3407           This variable conditionally defines the "HAS_SETEUID" symbol, which
3408           indicates to the C program that the seteuid() routine is available
3409           to change the effective uid of the current program.
3410
3411       "d_setgrent"
3412           From d_setgrent.U:
3413
3414           This variable conditionally defines the "HAS_SETGRENT" symbol,
3415           which indicates to the C program that the setgrent() routine is
3416           available for initializing sequential access to the group database.
3417
3418       "d_setgrent_r"
3419           From d_setgrent_r.U:
3420
3421           This variable conditionally defines the "HAS_SETGRENT_R" symbol,
3422           which indicates to the C program that the setgrent_r() routine is
3423           available.
3424
3425       "d_setgrps"
3426           From d_setgrps.U:
3427
3428           This variable conditionally defines the "HAS_SETGROUPS" symbol,
3429           which indicates to the C program that the setgroups() routine is
3430           available to set the list of process groups.
3431
3432       "d_sethent"
3433           From d_sethent.U:
3434
3435           This variable conditionally defines "HAS_SETHOSTENT" if
3436           sethostent() is available.
3437
3438       "d_sethostent_r"
3439           From d_sethostent_r.U:
3440
3441           This variable conditionally defines the "HAS_SETHOSTENT_R" symbol,
3442           which indicates to the C program that the sethostent_r() routine is
3443           available.
3444
3445       "d_setitimer"
3446           From d_setitimer.U:
3447
3448           This variable conditionally defines the "HAS_SETITIMER" symbol,
3449           which indicates to the C program that the setitimer() routine is
3450           available.
3451
3452       "d_setlinebuf"
3453           From d_setlnbuf.U:
3454
3455           This variable conditionally defines the "HAS_SETLINEBUF" symbol,
3456           which indicates to the C program that the setlinebuf() routine is
3457           available to change stderr or stdout from block-buffered or
3458           unbuffered to a line-buffered mode.
3459
3460       "d_setlocale"
3461           From d_setlocale.U:
3462
3463           This variable conditionally defines "HAS_SETLOCALE" if setlocale()
3464           is available to handle locale-specific ctype implementations.
3465
3466       "d_setlocale_accepts_any_locale_name"
3467           From d_setlocale.U:
3468
3469           This variable conditionally defines
3470           "SETLOCALE_ACCEPTS_ANY_LOCALE_NAME" if setlocale() accepts any
3471           locale name.
3472
3473       "d_setlocale_r"
3474           From d_setlocale_r.U:
3475
3476           This variable conditionally defines the "HAS_SETLOCALE_R" symbol,
3477           which indicates to the C program that the setlocale_r() routine is
3478           available.
3479
3480       "d_setnent"
3481           From d_setnent.U:
3482
3483           This variable conditionally defines "HAS_SETNETENT" if setnetent()
3484           is available.
3485
3486       "d_setnetent_r"
3487           From d_setnetent_r.U:
3488
3489           This variable conditionally defines the "HAS_SETNETENT_R" symbol,
3490           which indicates to the C program that the setnetent_r() routine is
3491           available.
3492
3493       "d_setpent"
3494           From d_setpent.U:
3495
3496           This variable conditionally defines "HAS_SETPROTOENT" if
3497           setprotoent() is available.
3498
3499       "d_setpgid"
3500           From d_setpgid.U:
3501
3502           This variable conditionally defines the "HAS_SETPGID" symbol if the
3503           setpgid(pid, gpid) function is available to set process group "ID".
3504
3505       "d_setpgrp"
3506           From d_setpgrp.U:
3507
3508           This variable conditionally defines "HAS_SETPGRP" if setpgrp() is
3509           available to set the current process group.
3510
3511       "d_setpgrp2"
3512           From d_setpgrp2.U:
3513
3514           This variable conditionally defines the HAS_SETPGRP2 symbol, which
3515           indicates to the C program that the setpgrp2() (as in DG/"UX")
3516           routine is available to set the current process group.
3517
3518       "d_setprior"
3519           From d_setprior.U:
3520
3521           This variable conditionally defines "HAS_SETPRIORITY" if
3522           setpriority() is available to set a process's priority.
3523
3524       "d_setproctitle"
3525           From d_setproctitle.U:
3526
3527           This variable conditionally defines the "HAS_SETPROCTITLE" symbol,
3528           which indicates to the C program that the setproctitle() routine is
3529           available.
3530
3531       "d_setprotoent_r"
3532           From d_setprotoent_r.U:
3533
3534           This variable conditionally defines the "HAS_SETPROTOENT_R" symbol,
3535           which indicates to the C program that the setprotoent_r() routine
3536           is available.
3537
3538       "d_setpwent"
3539           From d_setpwent.U:
3540
3541           This variable conditionally defines the "HAS_SETPWENT" symbol,
3542           which indicates to the C program that the setpwent() routine is
3543           available for initializing sequential access to the passwd
3544           database.
3545
3546       "d_setpwent_r"
3547           From d_setpwent_r.U:
3548
3549           This variable conditionally defines the "HAS_SETPWENT_R" symbol,
3550           which indicates to the C program that the setpwent_r() routine is
3551           available.
3552
3553       "d_setregid"
3554           From d_setregid.U:
3555
3556           This variable conditionally defines "HAS_SETREGID" if setregid() is
3557           available to change the real and effective gid of the current
3558           process.
3559
3560       "d_setresgid"
3561           From d_setregid.U:
3562
3563           This variable conditionally defines "HAS_SETRESGID" if setresgid()
3564           is available to change the real, effective and saved gid of the
3565           current process.
3566
3567       "d_setresuid"
3568           From d_setreuid.U:
3569
3570           This variable conditionally defines "HAS_SETREUID" if setresuid()
3571           is available to change the real, effective and saved uid of the
3572           current process.
3573
3574       "d_setreuid"
3575           From d_setreuid.U:
3576
3577           This variable conditionally defines "HAS_SETREUID" if setreuid() is
3578           available to change the real and effective uid of the current
3579           process.
3580
3581       "d_setrgid"
3582           From d_setrgid.U:
3583
3584           This variable conditionally defines the "HAS_SETRGID" symbol, which
3585           indicates to the C program that the setrgid() routine is available
3586           to change the real gid of the current program.
3587
3588       "d_setruid"
3589           From d_setruid.U:
3590
3591           This variable conditionally defines the "HAS_SETRUID" symbol, which
3592           indicates to the C program that the setruid() routine is available
3593           to change the real uid of the current program.
3594
3595       "d_setsent"
3596           From d_setsent.U:
3597
3598           This variable conditionally defines "HAS_SETSERVENT" if
3599           setservent() is available.
3600
3601       "d_setservent_r"
3602           From d_setservent_r.U:
3603
3604           This variable conditionally defines the "HAS_SETSERVENT_R" symbol,
3605           which indicates to the C program that the setservent_r() routine is
3606           available.
3607
3608       "d_setsid"
3609           From d_setsid.U:
3610
3611           This variable conditionally defines "HAS_SETSID" if setsid() is
3612           available to set the process group "ID".
3613
3614       "d_setvbuf"
3615           From d_setvbuf.U:
3616
3617           This variable conditionally defines the "HAS_SETVBUF" symbol, which
3618           indicates to the C program that the setvbuf() routine is available
3619           to change buffering on an open stdio stream.
3620
3621       "d_shm"
3622           From d_shm.U:
3623
3624           This variable conditionally defines the "HAS_SHM" symbol, which
3625           indicates that the entire shm*(2) library is present.
3626
3627       "d_shmat"
3628           From d_shmat.U:
3629
3630           This variable conditionally defines the "HAS_SHMAT" symbol, which
3631           indicates to the C program that the shmat() routine is available.
3632
3633       "d_shmatprototype"
3634           From d_shmat.U:
3635
3636           This variable conditionally defines the "HAS_SHMAT_PROTOTYPE"
3637           symbol, which indicates that sys/shm.h has a prototype for shmat.
3638
3639       "d_shmctl"
3640           From d_shmctl.U:
3641
3642           This variable conditionally defines the "HAS_SHMCTL" symbol, which
3643           indicates to the C program that the shmctl() routine is available.
3644
3645       "d_shmdt"
3646           From d_shmdt.U:
3647
3648           This variable conditionally defines the "HAS_SHMDT" symbol, which
3649           indicates to the C program that the shmdt() routine is available.
3650
3651       "d_shmget"
3652           From d_shmget.U:
3653
3654           This variable conditionally defines the "HAS_SHMGET" symbol, which
3655           indicates to the C program that the shmget() routine is available.
3656
3657       "d_sigaction"
3658           From d_sigaction.U:
3659
3660           This variable conditionally defines the "HAS_SIGACTION" symbol,
3661           which indicates that the Vr4 sigaction() routine is available.
3662
3663       "d_siginfo_si_addr"
3664           From d_siginfo_si.U:
3665
3666           This variable conditionally defines the "HAS_SIGINFO_SI_ADDR"
3667           symbol, which indicates that the siginfo_t struct has the si_addr
3668           member.
3669
3670       "d_siginfo_si_band"
3671           From d_siginfo_si.U:
3672
3673           This variable conditionally defines the "HAS_SIGINFO_SI_BAND"
3674           symbol, which indicates that the siginfo_t struct has the si_band
3675           member.
3676
3677       "d_siginfo_si_errno"
3678           From d_siginfo_si.U:
3679
3680           This variable conditionally defines the "HAS_SIGINFO_SI_ERRNO"
3681           symbol, which indicates that the siginfo_t struct has the si_errno
3682           member.
3683
3684       "d_siginfo_si_fd"
3685           From d_siginfo_si.U:
3686
3687           This variable conditionally defines the "HAS_SIGINFO_SI_FD" symbol,
3688           which indicates that the siginfo_t struct has the si_fd member.
3689
3690       "d_siginfo_si_pid"
3691           From d_siginfo_si.U:
3692
3693           This variable conditionally defines the "HAS_SIGINFO_SI_PID"
3694           symbol, which indicates that the siginfo_t struct has the si_pid
3695           member.
3696
3697       "d_siginfo_si_status"
3698           From d_siginfo_si.U:
3699
3700           This variable conditionally defines the "HAS_SIGINFO_SI_STATUS"
3701           symbol, which indicates that the siginfo_t struct has the si_status
3702           member.
3703
3704       "d_siginfo_si_uid"
3705           From d_siginfo_si.U:
3706
3707           This variable conditionally defines the "HAS_SIGINFO_SI_UID"
3708           symbol, which indicates that the siginfo_t struct has the si_uid
3709           member.
3710
3711       "d_siginfo_si_value"
3712           From d_siginfo_si.U:
3713
3714           This variable conditionally defines the "HAS_SIGINFO_SI_VALUE"
3715           symbol, which indicates that the siginfo_t struct has the si_value
3716           member.
3717
3718       "d_signbit"
3719           From d_signbit.U:
3720
3721           This variable conditionally defines the "HAS_SIGNBIT" symbol, which
3722           indicates to the C program that the signbit() routine is available
3723           and safe to use with perl's intern "NV" type.
3724
3725       "d_sigprocmask"
3726           From d_sigprocmask.U:
3727
3728           This variable conditionally defines "HAS_SIGPROCMASK" if
3729           sigprocmask() is available to examine or change the signal mask of
3730           the calling process.
3731
3732       "d_sigsetjmp"
3733           From d_sigsetjmp.U:
3734
3735           This variable conditionally defines the "HAS_SIGSETJMP" symbol,
3736           which indicates that the sigsetjmp() routine is available to call
3737           setjmp() and optionally save the process's signal mask.
3738
3739       "d_sin6_scope_id"
3740           From d_socket.U:
3741
3742           This variable conditionally defines the HAS_SIN6_SCOPE_ID symbol,
3743           which indicates that a struct sockaddr_in6 structure has the
3744           sin6_scope_id member.
3745
3746       "d_sitearch"
3747           From sitearch.U:
3748
3749           This variable conditionally defines "SITEARCH" to hold the pathname
3750           of architecture-dependent library files for $package.  If $sitearch
3751           is the same as $archlib, then this is set to undef.
3752
3753       "d_snprintf"
3754           From d_snprintf.U:
3755
3756           This variable conditionally defines the "HAS_SNPRINTF" symbol,
3757           which indicates to the C program that the snprintf () library
3758           function is available.
3759
3760       "d_sockaddr_in6"
3761           From d_socket.U:
3762
3763           This variable conditionally defines the HAS_SOCKADDR_IN6 symbol,
3764           which indicates the availability of a struct sockaddr_in6.
3765
3766       "d_sockaddr_sa_len"
3767           From d_socket.U:
3768
3769           This variable conditionally defines the "HAS_SOCKADDR_SA_LEN"
3770           symbol, which indicates that a struct sockaddr structure has the
3771           sa_len member.
3772
3773       "d_sockaddr_storage"
3774           From d_socket.U:
3775
3776           This variable conditionally defines the "HAS_SOCKADDR_STORAGE"
3777           symbol, which indicates the availability of a struct
3778           sockaddr_storage.
3779
3780       "d_sockatmark"
3781           From d_sockatmark.U:
3782
3783           This variable conditionally defines the "HAS_SOCKATMARK" symbol,
3784           which indicates to the C program that the sockatmark() routine is
3785           available.
3786
3787       "d_sockatmarkproto"
3788           From d_sockatmarkproto.U:
3789
3790           This variable conditionally defines the "HAS_SOCKATMARK_PROTO"
3791           symbol, which indicates to the C program that the system provides a
3792           prototype for the sockatmark() function.  Otherwise, it is up to
3793           the program to supply one.
3794
3795       "d_socket"
3796           From d_socket.U:
3797
3798           This variable conditionally defines "HAS_SOCKET", which indicates
3799           that the "BSD" socket interface is supported.
3800
3801       "d_socklen_t"
3802           From d_socklen_t.U:
3803
3804           This symbol will be defined if the C compiler supports socklen_t.
3805
3806       "d_sockpair"
3807           From d_socket.U:
3808
3809           This variable conditionally defines the "HAS_SOCKETPAIR" symbol,
3810           which indicates that the "BSD" socketpair() is supported.
3811
3812       "d_socks5_init"
3813           From d_socks5_init.U:
3814
3815           This variable conditionally defines the HAS_SOCKS5_INIT symbol,
3816           which indicates to the C program that the socks5_init() routine is
3817           available.
3818
3819       "d_sqrtl"
3820           From d_sqrtl.U:
3821
3822           This variable conditionally defines the "HAS_SQRTL" symbol, which
3823           indicates to the C program that the sqrtl() routine is available.
3824
3825       "d_srand48_r"
3826           From d_srand48_r.U:
3827
3828           This variable conditionally defines the HAS_SRAND48_R symbol, which
3829           indicates to the C program that the srand48_r() routine is
3830           available.
3831
3832       "d_srandom_r"
3833           From d_srandom_r.U:
3834
3835           This variable conditionally defines the "HAS_SRANDOM_R" symbol,
3836           which indicates to the C program that the srandom_r() routine is
3837           available.
3838
3839       "d_sresgproto"
3840           From d_sresgproto.U:
3841
3842           This variable conditionally defines the "HAS_SETRESGID_PROTO"
3843           symbol, which indicates to the C program that the system provides a
3844           prototype for the setresgid() function.  Otherwise, it is up to the
3845           program to supply one.
3846
3847       "d_sresuproto"
3848           From d_sresuproto.U:
3849
3850           This variable conditionally defines the "HAS_SETRESUID_PROTO"
3851           symbol, which indicates to the C program that the system provides a
3852           prototype for the setresuid() function.  Otherwise, it is up to the
3853           program to supply one.
3854
3855       "d_stat"
3856           From d_stat.U:
3857
3858           This variable conditionally defines "HAS_STAT" if stat() is
3859           available to get file status.
3860
3861       "d_statblks"
3862           From d_statblks.U:
3863
3864           This variable conditionally defines "USE_STAT_BLOCKS" if this
3865           system has a stat structure declaring st_blksize and st_blocks.
3866
3867       "d_statfs_f_flags"
3868           From d_statfs_f_flags.U:
3869
3870           This variable conditionally defines the "HAS_STRUCT_STATFS_F_FLAGS"
3871           symbol, which indicates to struct statfs from has f_flags member.
3872           This kind of struct statfs is coming from sys/mount.h ("BSD"), not
3873           from sys/statfs.h ("SYSV").
3874
3875       "d_statfs_s"
3876           From d_statfs_s.U:
3877
3878           This variable conditionally defines the "HAS_STRUCT_STATFS" symbol,
3879           which indicates that the struct statfs is supported.
3880
3881       "d_static_inline"
3882           From d_static_inline.U:
3883
3884           This variable conditionally defines the "HAS_STATIC_INLINE" symbol,
3885           which indicates that the C compiler supports C99-style static
3886           inline.  That is, the function can't be called from another
3887           translation unit.
3888
3889       "d_statvfs"
3890           From d_statvfs.U:
3891
3892           This variable conditionally defines the "HAS_STATVFS" symbol, which
3893           indicates to the C program that the statvfs() routine is available.
3894
3895       "d_stdio_cnt_lval"
3896           From d_stdstdio.U:
3897
3898           This variable conditionally defines "STDIO_CNT_LVALUE" if the
3899           "FILE_cnt" macro can be used as an lvalue.
3900
3901       "d_stdio_ptr_lval"
3902           From d_stdstdio.U:
3903
3904           This variable conditionally defines "STDIO_PTR_LVALUE" if the
3905           "FILE_ptr" macro can be used as an lvalue.
3906
3907       "d_stdio_ptr_lval_nochange_cnt"
3908           From d_stdstdio.U:
3909
3910           This symbol is defined if using the "FILE_ptr" macro as an lvalue
3911           to increase the pointer by n leaves File_cnt(fp) unchanged.
3912
3913       "d_stdio_ptr_lval_sets_cnt"
3914           From d_stdstdio.U:
3915
3916           This symbol is defined if using the "FILE_ptr" macro as an lvalue
3917           to increase the pointer by n has the side effect of decreasing the
3918           value of File_cnt(fp) by n.
3919
3920       "d_stdio_stream_array"
3921           From stdio_streams.U:
3922
3923           This variable tells whether there is an array holding the stdio
3924           streams.
3925
3926       "d_stdiobase"
3927           From d_stdstdio.U:
3928
3929           This variable conditionally defines "USE_STDIO_BASE" if this system
3930           has a "FILE" structure declaring a usable _base field (or
3931           equivalent) in stdio.h.
3932
3933       "d_stdstdio"
3934           From d_stdstdio.U:
3935
3936           This variable conditionally defines "USE_STDIO_PTR" if this system
3937           has a "FILE" structure declaring usable _ptr and _cnt fields (or
3938           equivalent) in stdio.h.
3939
3940       "d_strcoll"
3941           From d_strcoll.U:
3942
3943           This variable conditionally defines "HAS_STRCOLL" if strcoll() is
3944           available to compare strings using collating information.
3945
3946       "d_strerror_l"
3947           From d_strerror_l.U:
3948
3949           This variable conditionally defines the "HAS_STRERROR_L" symbol,
3950           which indicates to the C program that the strerror_l() routine is
3951           available to return the error message for a given errno value in a
3952           particular locale (identified by a locale_t object).
3953
3954       "d_strerror_r"
3955           From d_strerror_r.U:
3956
3957           This variable conditionally defines the "HAS_STRERROR_R" symbol,
3958           which indicates to the C program that the strerror_r() routine is
3959           available.
3960
3961       "d_strftime"
3962           From d_strftime.U:
3963
3964           This variable conditionally defines the "HAS_STRFTIME" symbol,
3965           which indicates to the C program that the strftime() routine is
3966           available.
3967
3968       "d_strlcat"
3969           From d_strlcat.U:
3970
3971           This variable conditionally defines the "HAS_STRLCAT" symbol, which
3972           indicates to the C program that the strlcat () routine is
3973           available.
3974
3975       "d_strlcpy"
3976           From d_strlcpy.U:
3977
3978           This variable conditionally defines the "HAS_STRLCPY" symbol, which
3979           indicates to the C program that the strlcpy () routine is
3980           available.
3981
3982       "d_strnlen"
3983           From d_strnlen.U:
3984
3985           This variable conditionally defines the "HAS_STRNLEN" symbol, which
3986           indicates to the C program that the strnlen () routine is
3987           available.
3988
3989       "d_strtod"
3990           From d_strtod.U:
3991
3992           This variable conditionally defines the "HAS_STRTOD" symbol, which
3993           indicates to the C program that the strtod() routine is available
3994           to provide better numeric string conversion than atof().
3995
3996       "d_strtod_l"
3997           From d_strtod_l.U:
3998
3999           This variable conditionally defines the "HAS_STRTOD_L" symbol,
4000           which indicates to the C program that the strtod_l() routine is
4001           available.
4002
4003       "d_strtol"
4004           From d_strtol.U:
4005
4006           This variable conditionally defines the "HAS_STRTOL" symbol, which
4007           indicates to the C program that the strtol() routine is available
4008           to provide better numeric string conversion than atoi() and
4009           friends.
4010
4011       "d_strtold"
4012           From d_strtold.U:
4013
4014           This variable conditionally defines the "HAS_STRTOLD" symbol, which
4015           indicates to the C program that the strtold() routine is available.
4016
4017       "d_strtold_l"
4018           From d_strtold_l.U:
4019
4020           This variable conditionally defines the "HAS_STRTOLD_L" symbol,
4021           which indicates to the C program that the strtold_l() routine is
4022           available.
4023
4024       "d_strtoll"
4025           From d_strtoll.U:
4026
4027           This variable conditionally defines the "HAS_STRTOLL" symbol, which
4028           indicates to the C program that the strtoll() routine is available.
4029
4030       "d_strtoq"
4031           From d_strtoq.U:
4032
4033           This variable conditionally defines the "HAS_STRTOQ" symbol, which
4034           indicates to the C program that the strtoq() routine is available.
4035
4036       "d_strtoul"
4037           From d_strtoul.U:
4038
4039           This variable conditionally defines the "HAS_STRTOUL" symbol, which
4040           indicates to the C program that the strtoul() routine is available
4041           to provide conversion of strings to unsigned long.
4042
4043       "d_strtoull"
4044           From d_strtoull.U:
4045
4046           This variable conditionally defines the "HAS_STRTOULL" symbol,
4047           which indicates to the C program that the strtoull() routine is
4048           available.
4049
4050       "d_strtouq"
4051           From d_strtouq.U:
4052
4053           This variable conditionally defines the "HAS_STRTOUQ" symbol, which
4054           indicates to the C program that the strtouq() routine is available.
4055
4056       "d_strxfrm"
4057           From d_strxfrm.U:
4058
4059           This variable conditionally defines "HAS_STRXFRM" if strxfrm() is
4060           available to transform strings.
4061
4062       "d_strxfrm_l"
4063           From d_strxfrm_l.U:
4064
4065           This variable conditionally defines "HAS_STRXFRM_L" if strxfrm_l()
4066           is available to transform strings.
4067
4068       "d_suidsafe"
4069           From d_dosuid.U:
4070
4071           This variable conditionally defines "SETUID_SCRIPTS_ARE_SECURE_NOW"
4072           if setuid scripts can be secure.  This test looks in /dev/fd/.
4073
4074       "d_symlink"
4075           From d_symlink.U:
4076
4077           This variable conditionally defines the "HAS_SYMLINK" symbol, which
4078           indicates to the C program that the symlink() routine is available
4079           to create symbolic links.
4080
4081       "d_syscall"
4082           From d_syscall.U:
4083
4084           This variable conditionally defines "HAS_SYSCALL" if syscall() is
4085           available call arbitrary system calls.
4086
4087       "d_syscallproto"
4088           From d_syscallproto.U:
4089
4090           This variable conditionally defines the "HAS_SYSCALL_PROTO" symbol,
4091           which indicates to the C program that the system provides a
4092           prototype for the syscall() function.  Otherwise, it is up to the
4093           program to supply one.
4094
4095       "d_sysconf"
4096           From d_sysconf.U:
4097
4098           This variable conditionally defines the "HAS_SYSCONF" symbol, which
4099           indicates to the C program that the sysconf() routine is available
4100           to determine system related limits and options.
4101
4102       "d_sysernlst"
4103           From d_strerror.U:
4104
4105           This variable conditionally defines "HAS_SYS_ERRNOLIST" if
4106           sys_errnolist[] is available to translate error numbers to the
4107           symbolic name.
4108
4109       "d_syserrlst"
4110           From d_strerror.U:
4111
4112           This variable conditionally defines "HAS_SYS_ERRLIST" if
4113           sys_errlist[] is available to translate error numbers to strings.
4114
4115       "d_system"
4116           From d_system.U:
4117
4118           This variable conditionally defines "HAS_SYSTEM" if system() is
4119           available to issue a shell command.
4120
4121       "d_tcgetpgrp"
4122           From d_tcgtpgrp.U:
4123
4124           This variable conditionally defines the "HAS_TCGETPGRP" symbol,
4125           which indicates to the C program that the tcgetpgrp() routine is
4126           available.  to get foreground process group "ID".
4127
4128       "d_tcsetpgrp"
4129           From d_tcstpgrp.U:
4130
4131           This variable conditionally defines the "HAS_TCSETPGRP" symbol,
4132           which indicates to the C program that the tcsetpgrp() routine is
4133           available to set foreground process group "ID".
4134
4135       "d_telldir"
4136           From d_readdir.U:
4137
4138           This variable conditionally defines "HAS_TELLDIR" if telldir() is
4139           available.
4140
4141       "d_telldirproto"
4142           From d_telldirproto.U:
4143
4144           This variable conditionally defines the "HAS_TELLDIR_PROTO" symbol,
4145           which indicates to the C program that the system provides a
4146           prototype for the telldir() function.  Otherwise, it is up to the
4147           program to supply one.
4148
4149       "d_tgamma"
4150           From d_tgamma.U:
4151
4152           This variable conditionally defines the "HAS_TGAMMA" symbol, which
4153           indicates to the C program that the tgamma() routine is available
4154           for the gamma function.  See also d_lgamma.
4155
4156       "d_thread_local"
4157           From d_thread_local.U:
4158
4159           This variable conditionally defines the "PERL_THREAD_LOCAL" symbol.
4160           In turn that gives a linkage specification for thread-local
4161           storage.
4162
4163       "d_thread_safe_nl_langinfo_l"
4164           From d_nl_langinfo_l.U:
4165
4166           This variable contains the eventual value of the
4167           "HAS_THREAD_SAFE_NL_LANGINFO_L" symbol, which indicates if the
4168           nl_langinfo_l() function exists and is thread-safe.
4169
4170       "d_time"
4171           From d_time.U:
4172
4173           This variable conditionally defines the "HAS_TIME" symbol, which
4174           indicates that the time() routine exists.  The time() routine is
4175           normally provided on "UNIX" systems.
4176
4177       "d_timegm"
4178           From d_timegm.U:
4179
4180           This variable conditionally defines the "HAS_TIMEGM" symbol, which
4181           indicates to the C program that the timegm () routine is available.
4182
4183       "d_times"
4184           From d_times.U:
4185
4186           This variable conditionally defines the "HAS_TIMES" symbol, which
4187           indicates that the times() routine exists.  The times() routine is
4188           normally provided on "UNIX" systems. You may have to include
4189           <sys/times.h>.
4190
4191       "d_tm_tm_gmtoff"
4192           From i_time.U:
4193
4194           This variable conditionally defines "HAS_TM_TM_GMTOFF", which
4195           indicates to the C program that the struct tm has the tm_gmtoff
4196           field.
4197
4198       "d_tm_tm_zone"
4199           From i_time.U:
4200
4201           This variable conditionally defines "HAS_TM_TM_ZONE", which
4202           indicates to the C program that the struct tm has the tm_zone
4203           field.
4204
4205       "d_tmpnam_r"
4206           From d_tmpnam_r.U:
4207
4208           This variable conditionally defines the "HAS_TMPNAM_R" symbol,
4209           which indicates to the C program that the tmpnam_r() routine is
4210           available.
4211
4212       "d_towlower"
4213           From d_towlower.U:
4214
4215           This variable conditionally defines the "HAS_TOWLOWER" symbol,
4216           which indicates to the C program that the towlower() routine is
4217           available.
4218
4219       "d_towupper"
4220           From d_towupper.U:
4221
4222           This variable conditionally defines the "HAS_TOWUPPER" symbol,
4223           which indicates to the C program that the towupper() routine is
4224           available.
4225
4226       "d_trunc"
4227           From d_trunc.U:
4228
4229           This variable conditionally defines the "HAS_TRUNC" symbol, which
4230           indicates to the C program that the trunc() routine is available to
4231           round doubles towards zero.
4232
4233       "d_truncate"
4234           From d_truncate.U:
4235
4236           This variable conditionally defines "HAS_TRUNCATE" if truncate() is
4237           available to truncate files.
4238
4239       "d_truncl"
4240           From d_truncl.U:
4241
4242           This variable conditionally defines the "HAS_TRUNCL" symbol, which
4243           indicates to the C program that the truncl() routine is available
4244           to round long doubles towards zero. If copysignl is also present,
4245           we can emulate modfl.
4246
4247       "d_ttyname_r"
4248           From d_ttyname_r.U:
4249
4250           This variable conditionally defines the "HAS_TTYNAME_R" symbol,
4251           which indicates to the C program that the ttyname_r() routine is
4252           available.
4253
4254       "d_tzname"
4255           From d_tzname.U:
4256
4257           This variable conditionally defines "HAS_TZNAME" if tzname[] is
4258           available to access timezone names.
4259
4260       "d_u32align"
4261           From d_u32align.U:
4262
4263           This variable tells whether you must access character data through
4264           U32-aligned pointers.
4265
4266       "d_ualarm"
4267           From d_ualarm.U:
4268
4269           This variable conditionally defines the "HAS_UALARM" symbol, which
4270           indicates to the C program that the ualarm() routine is available.
4271
4272       "d_umask"
4273           From d_umask.U:
4274
4275           This variable conditionally defines the "HAS_UMASK" symbol, which
4276           indicates to the C program that the umask() routine is available.
4277           to set and get the value of the file creation mask.
4278
4279       "d_uname"
4280           From d_gethname.U:
4281
4282           This variable conditionally defines the "HAS_UNAME" symbol, which
4283           indicates to the C program that the uname() routine may be used to
4284           derive the host name.
4285
4286       "d_union_semun"
4287           From d_union_semun.U:
4288
4289           This variable conditionally defines "HAS_UNION_SEMUN" if the union
4290           semun is defined by including <sys/sem.h>.
4291
4292       "d_unlinkat"
4293           From d_fsat.U:
4294
4295           This variable conditionally defines the "HAS_UNLINKAT" symbol,
4296           which indicates the "POSIX" unlinkat() function isavailable.
4297
4298       "d_unordered"
4299           From d_unordered.U:
4300
4301           This variable conditionally defines the "HAS_UNORDERED" symbol,
4302           which indicates to the C program that the unordered() routine is
4303           available.
4304
4305       "d_unsetenv"
4306           From d_unsetenv.U:
4307
4308           This variable conditionally defines the "HAS_UNSETENV" symbol,
4309           which indicates to the C program that the unsetenv () routine is
4310           available.
4311
4312       "d_uselocale"
4313           From d_newlocale.U:
4314
4315           This variable conditionally defines the "HAS_USELOCALE" symbol,
4316           which indicates to the C program that the uselocale() routine is
4317           available to set the current locale for the calling thread.
4318
4319       "d_usleep"
4320           From d_usleep.U:
4321
4322           This variable conditionally defines "HAS_USLEEP" if usleep() is
4323           available to do high granularity sleeps.
4324
4325       "d_usleepproto"
4326           From d_usleepproto.U:
4327
4328           This variable conditionally defines the "HAS_USLEEP_PROTO" symbol,
4329           which indicates to the C program that the system provides a
4330           prototype for the usleep() function.  Otherwise, it is up to the
4331           program to supply one.
4332
4333       "d_ustat"
4334           From d_ustat.U:
4335
4336           This variable conditionally defines "HAS_USTAT" if ustat() is
4337           available to query file system statistics by dev_t.
4338
4339       "d_vendorarch"
4340           From vendorarch.U:
4341
4342           This variable conditionally defined "PERL_VENDORARCH".
4343
4344       "d_vendorbin"
4345           From vendorbin.U:
4346
4347           This variable conditionally defines "PERL_VENDORBIN".
4348
4349       "d_vendorlib"
4350           From vendorlib.U:
4351
4352           This variable conditionally defines "PERL_VENDORLIB".
4353
4354       "d_vendorscript"
4355           From vendorscript.U:
4356
4357           This variable conditionally defines "PERL_VENDORSCRIPT".
4358
4359       "d_vfork"
4360           From d_vfork.U:
4361
4362           This variable conditionally defines the "HAS_VFORK" symbol, which
4363           indicates the vfork() routine is available.
4364
4365       "d_void_closedir"
4366           From d_closedir.U:
4367
4368           This variable conditionally defines "VOID_CLOSEDIR" if closedir()
4369           does not return a value.
4370
4371       "d_voidsig"
4372           From d_voidsig.U:
4373
4374           This variable conditionally defines "VOIDSIG" if this system
4375           declares "void (*signal(...))()" in signal.h.  The old way was to
4376           declare it as "int (*signal(...))()".
4377
4378       "d_voidtty"
4379           From i_sysioctl.U:
4380
4381           This variable conditionally defines "USE_IOCNOTTY" to indicate that
4382           the ioctl() call with "TIOCNOTTY" should be used to void tty
4383           association.  Otherwise (on "USG" probably), it is enough to close
4384           the standard file descriptors and do a setpgrp().
4385
4386       "d_vsnprintf"
4387           From d_snprintf.U:
4388
4389           This variable conditionally defines the "HAS_VSNPRINTF" symbol,
4390           which indicates to the C program that the vsnprintf () library
4391           function is available.
4392
4393       "d_wait4"
4394           From d_wait4.U:
4395
4396           This variable conditionally defines the HAS_WAIT4 symbol, which
4397           indicates the wait4() routine is available.
4398
4399       "d_waitpid"
4400           From d_waitpid.U:
4401
4402           This variable conditionally defines "HAS_WAITPID" if waitpid() is
4403           available to wait for child process.
4404
4405       "d_wcrtomb"
4406           From d_wcrtomb.U:
4407
4408           This variable conditionally defines the "HAS_WCRTOMB" symbol if the
4409           wcrtomb() routine is available to be used to convert a wide
4410           character into a multi-byte character.
4411
4412       "d_wcscmp"
4413           From d_wcscmp.U:
4414
4415           This variable conditionally defines the "HAS_WCSCMP" symbol if the
4416           wcscmp() routine is available and can be used to compare wide
4417           character strings.
4418
4419       "d_wcstombs"
4420           From d_wcstombs.U:
4421
4422           This variable conditionally defines the "HAS_WCSTOMBS" symbol,
4423           which indicates to the C program that the wcstombs() routine is
4424           available to convert wide character strings to multibyte strings.
4425
4426       "d_wcsxfrm"
4427           From d_wcsxfrm.U:
4428
4429           This variable conditionally defines the "HAS_WCSXFRM" symbol if the
4430           wcsxfrm() routine is available and can be used to compare wide
4431           character strings.
4432
4433       "d_wctomb"
4434           From d_wctomb.U:
4435
4436           This variable conditionally defines the "HAS_WCTOMB" symbol, which
4437           indicates to the C program that the wctomb() routine is available
4438           to convert a wide character to a multibyte.
4439
4440       "d_writev"
4441           From d_writev.U:
4442
4443           This variable conditionally defines the "HAS_WRITEV" symbol, which
4444           indicates to the C program that the writev() routine is available.
4445
4446       "d_xenix"
4447           From Guess.U:
4448
4449           This variable conditionally defines the symbol "XENIX", which
4450           alerts the C program that it runs under Xenix.
4451
4452       "date"
4453           From Loc.U:
4454
4455           This variable is used internally by Configure to determine the full
4456           pathname (if any) of the date program.  After Configure runs, the
4457           value is reset to a plain "date" and is not useful.
4458
4459       "db_hashtype"
4460           From i_db.U:
4461
4462           This variable contains the type of the hash structure element in
4463           the <db.h> header file.  In older versions of "DB", it was int,
4464           while in newer ones it is u_int32_t.
4465
4466       "db_prefixtype"
4467           From i_db.U:
4468
4469           This variable contains the type of the prefix structure element in
4470           the <db.h> header file.  In older versions of "DB", it was int,
4471           while in newer ones it is size_t.
4472
4473       "db_version_major"
4474           From i_db.U:
4475
4476           This variable contains the major version number of Berkeley "DB"
4477           found in the <db.h> header file.
4478
4479       "db_version_minor"
4480           From i_db.U:
4481
4482           This variable contains the minor version number of Berkeley "DB"
4483           found in the <db.h> header file.  For "DB" version 1 this is always
4484           0.
4485
4486       "db_version_patch"
4487           From i_db.U:
4488
4489           This variable contains the patch version number of Berkeley "DB"
4490           found in the <db.h> header file.  For "DB" version 1 this is always
4491           0.
4492
4493       "default_inc_excludes_dot"
4494           From defaultincdot.U:
4495
4496           When defined, remove the legacy . from @"INC"
4497
4498       "direntrytype"
4499           From i_dirent.U:
4500
4501           This symbol is set to "struct direct" or "struct dirent" depending
4502           on whether dirent is available or not. You should use this pseudo
4503           type to portably declare your directory entries.
4504
4505       "dlext"
4506           From dlext.U:
4507
4508           This variable contains the extension that is to be used for the
4509           dynamically loaded modules that perl generates.
4510
4511       "dlsrc"
4512           From dlsrc.U:
4513
4514           This variable contains the name of the dynamic loading file that
4515           will be used with the package.
4516
4517       "doubleinfbytes"
4518           From infnan.U:
4519
4520           This variable contains comma-separated list of hexadecimal bytes
4521           for the double precision infinity.
4522
4523       "doublekind"
4524           From longdblfio.U:
4525
4526           This variable, if defined, encodes the type of a double: 1 = "IEEE"
4527           754 32-bit little endian, 2 = "IEEE" 754 32-bit big endian, 3 =
4528           "IEEE" 754 64-bit little endian, 4 = "IEEE" 754 64-bit big endian,
4529           5 = "IEEE" 754 128-bit little endian, 6 = "IEEE" 754 128-bit big
4530           endian, 7 = "IEEE" 754 64-bit mixed endian le-be, 8 = "IEEE" 754
4531           64-bit mixed endian be-le, 9 = "VAX" 32bit little endian F float
4532           format 10 = "VAX" 64bit little endian D float format 11 = "VAX"
4533           64bit little endian G float format 12 = "IBM" 32bit format 13 =
4534           "IBM" 64bit format 14 = Cray 64bit format -1 = unknown format.
4535
4536       "doublemantbits"
4537           From mantbits.U:
4538
4539           This symbol, if defined, tells how many mantissa bits there are in
4540           double precision floating point format.  Note that this is usually
4541           "DBL_MANT_DIG" minus one, since with the standard "IEEE" 754
4542           formats "DBL_MANT_DIG" includes the implicit bit which doesn't
4543           really exist.
4544
4545       "doublenanbytes"
4546           From infnan.U:
4547
4548           This variable contains comma-separated list of hexadecimal bytes
4549           for the double precision not-a-number.
4550
4551       "doublesize"
4552           From doublesize.U:
4553
4554           This variable contains the value of the "DOUBLESIZE" symbol, which
4555           indicates to the C program how many bytes there are in a double.
4556
4557       "drand01"
4558           From randfunc.U:
4559
4560           Indicates the macro to be used to generate normalized random
4561           numbers.  Uses randfunc, often divided by (double) (((unsigned
4562           long) 1 << randbits)) in order to normalize the result.  In C
4563           programs, the macro "Drand01" is mapped to drand01.
4564
4565       "drand48_r_proto"
4566           From d_drand48_r.U:
4567
4568           This variable encodes the prototype of drand48_r.  It is zero if
4569           d_drand48_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
4570           of reentr.h if d_drand48_r is defined.
4571
4572       "dtrace"
4573           From usedtrace.U:
4574
4575           This variable holds the location of the dtrace executable.
4576
4577       "dtraceobject"
4578           From dtraceobject.U:
4579
4580           Whether we need to build an object file with the dtrace tool.
4581
4582       "dtracexnolibs"
4583           From dtraceobject.U:
4584
4585           Whether dtrace accepts -xnolibs.  If available we call dtrace -h
4586           and dtrace -G with -xnolibs to allow dtrace to run in a jail on
4587           FreeBSD.
4588
4589       "dynamic_ext"
4590           From Extensions.U:
4591
4592           This variable holds a list of "XS" extension files we want to link
4593           dynamically into the package.  It is used by Makefile.
4594
4595   e
4596       "eagain"
4597           From nblock_io.U:
4598
4599           This variable bears the symbolic errno code set by read() when no
4600           data is present on the file and non-blocking I/O was enabled
4601           (otherwise, read() blocks naturally).
4602
4603       "ebcdic"
4604           From ebcdic.U:
4605
4606           This variable conditionally defines "EBCDIC" if this system uses
4607           "EBCDIC" encoding.
4608
4609       "echo"
4610           From Loc.U:
4611
4612           This variable is used internally by Configure to determine the full
4613           pathname (if any) of the echo program.  After Configure runs, the
4614           value is reset to a plain "echo" and is not useful.
4615
4616       "egrep"
4617           From Loc.U:
4618
4619           This variable is used internally by Configure to determine the full
4620           pathname (if any) of the egrep program.  After Configure runs, the
4621           value is reset to a plain "egrep" and is not useful.
4622
4623       "emacs"
4624           From Loc.U:
4625
4626           This variable is defined but not used by Configure.  The value is
4627           the empty string and is not useful.
4628
4629       "endgrent_r_proto"
4630           From d_endgrent_r.U:
4631
4632           This variable encodes the prototype of endgrent_r.  It is zero if
4633           d_endgrent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4634           macros of reentr.h if d_endgrent_r is defined.
4635
4636       "endhostent_r_proto"
4637           From d_endhostent_r.U:
4638
4639           This variable encodes the prototype of endhostent_r.  It is zero if
4640           d_endhostent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4641           macros of reentr.h if d_endhostent_r is defined.
4642
4643       "endnetent_r_proto"
4644           From d_endnetent_r.U:
4645
4646           This variable encodes the prototype of endnetent_r.  It is zero if
4647           d_endnetent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4648           macros of reentr.h if d_endnetent_r is defined.
4649
4650       "endprotoent_r_proto"
4651           From d_endprotoent_r.U:
4652
4653           This variable encodes the prototype of endprotoent_r.  It is zero
4654           if d_endprotoent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4655           macros of reentr.h if d_endprotoent_r is defined.
4656
4657       "endpwent_r_proto"
4658           From d_endpwent_r.U:
4659
4660           This variable encodes the prototype of endpwent_r.  It is zero if
4661           d_endpwent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4662           macros of reentr.h if d_endpwent_r is defined.
4663
4664       "endservent_r_proto"
4665           From d_endservent_r.U:
4666
4667           This variable encodes the prototype of endservent_r.  It is zero if
4668           d_endservent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4669           macros of reentr.h if d_endservent_r is defined.
4670
4671       "eunicefix"
4672           From Init.U:
4673
4674           When running under Eunice this variable contains a command which
4675           will convert a shell script to the proper form of text file for it
4676           to be executable by the shell.  On other systems it is a no-op.
4677
4678       "exe_ext"
4679           From Unix.U:
4680
4681           This is an old synonym for _exe.
4682
4683       "expr"
4684           From Loc.U:
4685
4686           This variable is used internally by Configure to determine the full
4687           pathname (if any) of the expr program.  After Configure runs, the
4688           value is reset to a plain "expr" and is not useful.
4689
4690       "extensions"
4691           From Extensions.U:
4692
4693           This variable holds a list of all extension files (both "XS" and
4694           non-xs) installed with the package.  It is propagated to Config.pm
4695           and is typically used to test whether a particular extension is
4696           available.
4697
4698       "extern_C"
4699           From Csym.U:
4700
4701           "ANSI" C requires "extern" where C++ requires 'extern "C"'. This
4702           variable can be used in Configure to do the right thing.
4703
4704       "extras"
4705           From Extras.U:
4706
4707           This variable holds a list of extra modules to install.
4708
4709   f
4710       "fflushall"
4711           From fflushall.U:
4712
4713           This symbol, if defined, tells that to flush all pending stdio
4714           output one must loop through all the stdio file handles stored in
4715           an array and fflush them.  Note that if fflushNULL is defined,
4716           fflushall will not even be probed for and will be left undefined.
4717
4718       "fflushNULL"
4719           From fflushall.U:
4720
4721           This symbol, if defined, tells that fflush("NULL") correctly
4722           flushes all pending stdio output without side effects. In
4723           particular, on some platforms calling fflush("NULL") *still*
4724           corrupts "STDIN" if it is a pipe.
4725
4726       "find"
4727           From Loc.U:
4728
4729           This variable is defined but not used by Configure.  The value is
4730           the empty string and is not useful.
4731
4732       "firstmakefile"
4733           From Unix.U:
4734
4735           This variable defines the first file searched by make.  On unix, it
4736           is makefile (then Makefile).  On case-insensitive systems, it might
4737           be something else.  This is only used to deal with convoluted make
4738           depend tricks.
4739
4740       "flex"
4741           From Loc.U:
4742
4743           This variable is defined but not used by Configure.  The value is
4744           the empty string and is not useful.
4745
4746       "fpossize"
4747           From fpossize.U:
4748
4749           This variable contains the size of a fpostype in bytes.
4750
4751       "fpostype"
4752           From fpostype.U:
4753
4754           This variable defines Fpos_t to be something like fpos_t, long,
4755           uint, or whatever type is used to declare file positions in libc.
4756
4757       "freetype"
4758           From mallocsrc.U:
4759
4760           This variable contains the return type of free().  It is usually
4761           void, but occasionally int.
4762
4763       "from"
4764           From Cross.U:
4765
4766           This variable contains the command used by Configure to copy files
4767           from the target host.  Useful and available only during Perl build.
4768           The string ":" if not cross-compiling.
4769
4770       "full_ar"
4771           From Loc_ar.U:
4772
4773           This variable contains the full pathname to "ar", whether or not
4774           the user has specified "portability".  This is only used in the
4775           Makefile.SH.
4776
4777       "full_csh"
4778           From d_csh.U:
4779
4780           This variable contains the full pathname to "csh", whether or not
4781           the user has specified "portability".  This is only used in the
4782           compiled C program, and we assume that all systems which can share
4783           this executable will have the same full pathname to csh.
4784
4785       "full_sed"
4786           From Loc_sed.U:
4787
4788           This variable contains the full pathname to "sed", whether or not
4789           the user has specified "portability".  This is only used in the
4790           compiled C program, and we assume that all systems which can share
4791           this executable will have the same full pathname to sed.
4792
4793   g
4794       "gccansipedantic"
4795           From gccvers.U:
4796
4797           If "GNU" cc (gcc) is used, this variable will enable (if set) the
4798           -ansi and -pedantic ccflags for building core files (through cflags
4799           script). (See Porting/pumpkin.pod for full description).
4800
4801       "gccosandvers"
4802           From gccvers.U:
4803
4804           If "GNU" cc (gcc) is used, this variable holds the operating system
4805           and version used to compile gcc.  It is set to '' if not gcc, or if
4806           nothing useful can be parsed as the os version.
4807
4808       "gccversion"
4809           From gccvers.U:
4810
4811           If "GNU" cc (gcc) is used, this variable holds 1 or 2 to indicate
4812           whether the compiler is version 1 or 2.  This is used in setting
4813           some of the default cflags.  It is set to '' if not gcc.
4814
4815       "getgrent_r_proto"
4816           From d_getgrent_r.U:
4817
4818           This variable encodes the prototype of getgrent_r.  It is zero if
4819           d_getgrent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4820           macros of reentr.h if d_getgrent_r is defined.
4821
4822       "getgrgid_r_proto"
4823           From d_getgrgid_r.U:
4824
4825           This variable encodes the prototype of getgrgid_r.  It is zero if
4826           d_getgrgid_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4827           macros of reentr.h if d_getgrgid_r is defined.
4828
4829       "getgrnam_r_proto"
4830           From d_getgrnam_r.U:
4831
4832           This variable encodes the prototype of getgrnam_r.  It is zero if
4833           d_getgrnam_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4834           macros of reentr.h if d_getgrnam_r is defined.
4835
4836       "gethostbyaddr_r_proto"
4837           From d_gethostbyaddr_r.U:
4838
4839           This variable encodes the prototype of gethostbyaddr_r.  It is zero
4840           if d_gethostbyaddr_r is undef, and one of the
4841           "REENTRANT_PROTO_T_ABC" macros of reentr.h if d_gethostbyaddr_r is
4842           defined.
4843
4844       "gethostbyname_r_proto"
4845           From d_gethostbyname_r.U:
4846
4847           This variable encodes the prototype of gethostbyname_r.  It is zero
4848           if d_gethostbyname_r is undef, and one of the
4849           "REENTRANT_PROTO_T_ABC" macros of reentr.h if d_gethostbyname_r is
4850           defined.
4851
4852       "gethostent_r_proto"
4853           From d_gethostent_r.U:
4854
4855           This variable encodes the prototype of gethostent_r.  It is zero if
4856           d_gethostent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4857           macros of reentr.h if d_gethostent_r is defined.
4858
4859       "getlogin_r_proto"
4860           From d_getlogin_r.U:
4861
4862           This variable encodes the prototype of getlogin_r.  It is zero if
4863           d_getlogin_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4864           macros of reentr.h if d_getlogin_r is defined.
4865
4866       "getnetbyaddr_r_proto"
4867           From d_getnetbyaddr_r.U:
4868
4869           This variable encodes the prototype of getnetbyaddr_r.  It is zero
4870           if d_getnetbyaddr_r is undef, and one of the
4871           "REENTRANT_PROTO_T_ABC" macros of reentr.h if d_getnetbyaddr_r is
4872           defined.
4873
4874       "getnetbyname_r_proto"
4875           From d_getnetbyname_r.U:
4876
4877           This variable encodes the prototype of getnetbyname_r.  It is zero
4878           if d_getnetbyname_r is undef, and one of the
4879           "REENTRANT_PROTO_T_ABC" macros of reentr.h if d_getnetbyname_r is
4880           defined.
4881
4882       "getnetent_r_proto"
4883           From d_getnetent_r.U:
4884
4885           This variable encodes the prototype of getnetent_r.  It is zero if
4886           d_getnetent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4887           macros of reentr.h if d_getnetent_r is defined.
4888
4889       "getprotobyname_r_proto"
4890           From d_getprotobyname_r.U:
4891
4892           This variable encodes the prototype of getprotobyname_r.  It is
4893           zero if d_getprotobyname_r is undef, and one of the
4894           "REENTRANT_PROTO_T_ABC" macros of reentr.h if d_getprotobyname_r is
4895           defined.
4896
4897       "getprotobynumber_r_proto"
4898           From d_getprotobynumber_r.U:
4899
4900           This variable encodes the prototype of getprotobynumber_r.  It is
4901           zero if d_getprotobynumber_r is undef, and one of the
4902           "REENTRANT_PROTO_T_ABC" macros of reentr.h if d_getprotobynumber_r
4903           is defined.
4904
4905       "getprotoent_r_proto"
4906           From d_getprotoent_r.U:
4907
4908           This variable encodes the prototype of getprotoent_r.  It is zero
4909           if d_getprotoent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4910           macros of reentr.h if d_getprotoent_r is defined.
4911
4912       "getpwent_r_proto"
4913           From d_getpwent_r.U:
4914
4915           This variable encodes the prototype of getpwent_r.  It is zero if
4916           d_getpwent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4917           macros of reentr.h if d_getpwent_r is defined.
4918
4919       "getpwnam_r_proto"
4920           From d_getpwnam_r.U:
4921
4922           This variable encodes the prototype of getpwnam_r.  It is zero if
4923           d_getpwnam_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4924           macros of reentr.h if d_getpwnam_r is defined.
4925
4926       "getpwuid_r_proto"
4927           From d_getpwuid_r.U:
4928
4929           This variable encodes the prototype of getpwuid_r.  It is zero if
4930           d_getpwuid_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4931           macros of reentr.h if d_getpwuid_r is defined.
4932
4933       "getservbyname_r_proto"
4934           From d_getservbyname_r.U:
4935
4936           This variable encodes the prototype of getservbyname_r.  It is zero
4937           if d_getservbyname_r is undef, and one of the
4938           "REENTRANT_PROTO_T_ABC" macros of reentr.h if d_getservbyname_r is
4939           defined.
4940
4941       "getservbyport_r_proto"
4942           From d_getservbyport_r.U:
4943
4944           This variable encodes the prototype of getservbyport_r.  It is zero
4945           if d_getservbyport_r is undef, and one of the
4946           "REENTRANT_PROTO_T_ABC" macros of reentr.h if d_getservbyport_r is
4947           defined.
4948
4949       "getservent_r_proto"
4950           From d_getservent_r.U:
4951
4952           This variable encodes the prototype of getservent_r.  It is zero if
4953           d_getservent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4954           macros of reentr.h if d_getservent_r is defined.
4955
4956       "getspnam_r_proto"
4957           From d_getspnam_r.U:
4958
4959           This variable encodes the prototype of getspnam_r.  It is zero if
4960           d_getspnam_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4961           macros of reentr.h if d_getspnam_r is defined.
4962
4963       "gidformat"
4964           From gidf.U:
4965
4966           This variable contains the format string used for printing a Gid_t.
4967
4968       "gidsign"
4969           From gidsign.U:
4970
4971           This variable contains the signedness of a gidtype.  1 for
4972           unsigned, -1 for signed.
4973
4974       "gidsize"
4975           From gidsize.U:
4976
4977           This variable contains the size of a gidtype in bytes.
4978
4979       "gidtype"
4980           From gidtype.U:
4981
4982           This variable defines Gid_t to be something like gid_t, int,
4983           ushort, or whatever type is used to declare the return type of
4984           getgid().  Typically, it is the type of group ids in the kernel.
4985
4986       "glibpth"
4987           From libpth.U:
4988
4989           This variable holds the general path (space-separated) used to find
4990           libraries.  It may contain directories that do not exist on this
4991           platform, libpth is the cleaned-up version.
4992
4993       "gmake"
4994           From Loc.U:
4995
4996           This variable is used internally by Configure to determine the full
4997           pathname (if any) of the gmake program.  After Configure runs, the
4998           value is reset to a plain "gmake" and is not useful.
4999
5000       "gmtime_r_proto"
5001           From d_gmtime_r.U:
5002
5003           This variable encodes the prototype of gmtime_r.  It is zero if
5004           d_gmtime_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
5005           of reentr.h if d_gmtime_r is defined.
5006
5007       "gnulibc_version"
5008           From d_gnulibc.U:
5009
5010           This variable contains the version number of the "GNU" C library.
5011           It is usually something like 2.2.5.  It is a plain '' if this is
5012           not the "GNU" C library, or if the version is unknown.
5013
5014       "grep"
5015           From Loc.U:
5016
5017           This variable is used internally by Configure to determine the full
5018           pathname (if any) of the grep program.  After Configure runs, the
5019           value is reset to a plain "grep" and is not useful.
5020
5021       "groupcat"
5022           From nis.U:
5023
5024           This variable contains a command that produces the text of the
5025           /etc/group file.  This is normally "cat /etc/group", but can be
5026           "ypcat group" when "NIS" is used.  On some systems, such as os390,
5027           there may be no equivalent command, in which case this variable is
5028           unset.
5029
5030       "groupstype"
5031           From groupstype.U:
5032
5033           This variable defines Groups_t to be something like gid_t, int,
5034           ushort, or whatever type is used for the second argument to
5035           getgroups() and setgroups().  Usually, this is the same as gidtype
5036           (gid_t), but sometimes it isn't.
5037
5038       "gzip"
5039           From Loc.U:
5040
5041           This variable is used internally by Configure to determine the full
5042           pathname (if any) of the gzip program.  After Configure runs, the
5043           value is reset to a plain "gzip" and is not useful.
5044
5045   h
5046       "h_fcntl"
5047           From h_fcntl.U:
5048
5049           This is variable gets set in various places to tell i_fcntl that
5050           <fcntl.h> should be included.
5051
5052       "h_sysfile"
5053           From h_sysfile.U:
5054
5055           This is variable gets set in various places to tell i_sys_file that
5056           <sys/file.h> should be included.
5057
5058       "hint"
5059           From Oldconfig.U:
5060
5061           Gives the type of hints used for previous answers. May be one of
5062           "default", "recommended" or "previous".
5063
5064       "hostcat"
5065           From nis.U:
5066
5067           This variable contains a command that produces the text of the
5068           /etc/hosts file.  This is normally "cat /etc/hosts", but can be
5069           "ypcat hosts" when "NIS" is used.  On some systems, such as os390,
5070           there may be no equivalent command, in which case this variable is
5071           unset.
5072
5073       "hostgenerate"
5074           From Cross.U:
5075
5076           This variable contains the path to a generate_uudmap binary that
5077           can be run on the host "OS" when cross-compiling.  Useful and
5078           available only during Perl build.  Empty string '' if not cross-
5079           compiling.
5080
5081       "hostosname"
5082           From Cross.U:
5083
5084           This variable contains the original value of $^O for hostperl when
5085           cross-compiling.  This is useful to pick the proper tools when
5086           running build code in the host.  Empty string '' if not cross-
5087           compiling.
5088
5089       "hostperl"
5090           From Cross.U:
5091
5092           This variable contains the path to a miniperl binary that can be
5093           run on the host "OS" when cross-compiling.  Useful and available
5094           only during Perl build.  Empty string '' if not cross-compiling.
5095
5096       "html1dir"
5097           From html1dir.U:
5098
5099           This variable contains the name of the directory in which html
5100           source pages are to be put.  This directory is for pages that
5101           describe whole programs, not libraries or modules.  It is intended
5102           to correspond roughly to section 1 of the Unix manuals.
5103
5104       "html1direxp"
5105           From html1dir.U:
5106
5107           This variable is the same as the html1dir variable, but is filename
5108           expanded at configuration time, for convenient use in makefiles.
5109
5110       "html3dir"
5111           From html3dir.U:
5112
5113           This variable contains the name of the directory in which html
5114           source pages are to be put.  This directory is for pages that
5115           describe libraries or modules.  It is intended to correspond
5116           roughly to section 3 of the Unix manuals.
5117
5118       "html3direxp"
5119           From html3dir.U:
5120
5121           This variable is the same as the html3dir variable, but is filename
5122           expanded at configuration time, for convenient use in makefiles.
5123
5124   i
5125       "i16size"
5126           From perlxv.U:
5127
5128           This variable is the size of an I16 in bytes.
5129
5130       "i16type"
5131           From perlxv.U:
5132
5133           This variable contains the C type used for Perl's I16.
5134
5135       "i32size"
5136           From perlxv.U:
5137
5138           This variable is the size of an I32 in bytes.
5139
5140       "i32type"
5141           From perlxv.U:
5142
5143           This variable contains the C type used for Perl's I32.
5144
5145       "i64size"
5146           From perlxv.U:
5147
5148           This variable is the size of an I64 in bytes.
5149
5150       "i64type"
5151           From perlxv.U:
5152
5153           This variable contains the C type used for Perl's I64.
5154
5155       "i8size"
5156           From perlxv.U:
5157
5158           This variable is the size of an I8 in bytes.
5159
5160       "i8type"
5161           From perlxv.U:
5162
5163           This variable contains the C type used for Perl's I8.
5164
5165       "i_arpainet"
5166           From i_arpainet.U:
5167
5168           This variable conditionally defines the "I_ARPA_INET" symbol, and
5169           indicates whether a C program should include <arpa/inet.h>.
5170
5171       "i_bfd"
5172           From i_bfd.U:
5173
5174           This variable conditionally defines the "I_BFD" symbol, and
5175           indicates whether a C program can include <bfd.h>.
5176
5177       "i_bsdioctl"
5178           From i_sysioctl.U:
5179
5180           This variable conditionally defines the "I_SYS_BSDIOCTL" symbol,
5181           which indicates to the C program that <sys/bsdioctl.h> exists and
5182           should be included.
5183
5184       "i_crypt"
5185           From i_crypt.U:
5186
5187           This variable conditionally defines the "I_CRYPT" symbol, and
5188           indicates whether a C program should include <crypt.h>.
5189
5190       "i_db"
5191           From i_db.U:
5192
5193           This variable conditionally defines the "I_DB" symbol, and
5194           indicates whether a C program may include Berkeley's "DB" include
5195           file <db.h>.
5196
5197       "i_dbm"
5198           From i_dbm.U:
5199
5200           This variable conditionally defines the "I_DBM" symbol, which
5201           indicates to the C program that <dbm.h> exists and should be
5202           included.
5203
5204       "i_dirent"
5205           From i_dirent.U:
5206
5207           This variable conditionally defines "I_DIRENT", which indicates to
5208           the C program that it should include <dirent.h>.
5209
5210       "i_dlfcn"
5211           From i_dlfcn.U:
5212
5213           This variable conditionally defines the "I_DLFCN" symbol, which
5214           indicates to the C program that <dlfcn.h> exists and should be
5215           included.
5216
5217       "i_execinfo"
5218           From i_execinfo.U:
5219
5220           This variable conditionally defines the "I_EXECINFO" symbol, and
5221           indicates whether a C program may include <execinfo.h>, for
5222           backtrace() support.
5223
5224       "i_fcntl"
5225           From i_fcntl.U:
5226
5227           This variable controls the value of "I_FCNTL" (which tells the C
5228           program to include <fcntl.h>).
5229
5230       "i_fenv"
5231           From i_fenv.U:
5232
5233           This variable conditionally defines the "I_FENV" symbol, which
5234           indicates to the C program that <fenv.h> exists and should be
5235           included.
5236
5237       "i_fp"
5238           From i_fp.U:
5239
5240           This variable conditionally defines the "I_FP" symbol, and
5241           indicates whether a C program should include <fp.h>.
5242
5243       "i_fp_class"
5244           From i_fp_class.U:
5245
5246           This variable conditionally defines the "I_FP_CLASS" symbol, and
5247           indicates whether a C program should include <fp_class.h>.
5248
5249       "i_gdbm"
5250           From i_gdbm.U:
5251
5252           This variable conditionally defines the "I_GDBM" symbol, which
5253           indicates to the C program that <gdbm.h> exists and should be
5254           included.
5255
5256       "i_gdbm_ndbm"
5257           From i_ndbm.U:
5258
5259           This variable conditionally defines the "I_GDBM_NDBM" symbol, which
5260           indicates to the C program that <gdbm-ndbm.h> exists and should be
5261           included.  This is the location of the ndbm.h compatibility file in
5262           Debian 4.0.
5263
5264       "i_gdbmndbm"
5265           From i_ndbm.U:
5266
5267           This variable conditionally defines the "I_GDBMNDBM" symbol, which
5268           indicates to the C program that <gdbm/ndbm.h> exists and should be
5269           included.  This was the location of the ndbm.h compatibility file
5270           in RedHat 7.1.
5271
5272       "i_grp"
5273           From i_grp.U:
5274
5275           This variable conditionally defines the "I_GRP" symbol, and
5276           indicates whether a C program should include <grp.h>.
5277
5278       "i_ieeefp"
5279           From i_ieeefp.U:
5280
5281           This variable conditionally defines the "I_IEEEFP" symbol, and
5282           indicates whether a C program should include <ieeefp.h>.
5283
5284       "i_inttypes"
5285           From i_inttypes.U:
5286
5287           This variable conditionally defines the "I_INTTYPES" symbol, and
5288           indicates whether a C program should include <inttypes.h>.
5289
5290       "i_langinfo"
5291           From i_langinfo.U:
5292
5293           This variable conditionally defines the "I_LANGINFO" symbol, and
5294           indicates whether a C program should include <langinfo.h>.
5295
5296       "i_libutil"
5297           From i_libutil.U:
5298
5299           This variable conditionally defines the "I_LIBUTIL" symbol, and
5300           indicates whether a C program should include <libutil.h>.
5301
5302       "i_locale"
5303           From i_locale.U:
5304
5305           This variable conditionally defines the "I_LOCALE" symbol, and
5306           indicates whether a C program should include <locale.h>.
5307
5308       "i_machcthr"
5309           From i_machcthr.U:
5310
5311           This variable conditionally defines the "I_MACH_CTHREADS" symbol,
5312           and indicates whether a C program should include <mach/cthreads.h>.
5313
5314       "i_malloc"
5315           From i_malloc.U:
5316
5317           This variable conditionally defines the "I_MALLOC" symbol, and
5318           indicates whether a C program should include <malloc.h>.
5319
5320       "i_mallocmalloc"
5321           From i_mallocmalloc.U:
5322
5323           This variable conditionally defines the "I_MALLOCMALLOC" symbol,
5324           and indicates whether a C program should include <malloc/malloc.h>.
5325
5326       "i_mntent"
5327           From i_mntent.U:
5328
5329           This variable conditionally defines the "I_MNTENT" symbol, and
5330           indicates whether a C program should include <mntent.h>.
5331
5332       "i_ndbm"
5333           From i_ndbm.U:
5334
5335           This variable conditionally defines the "I_NDBM" symbol, which
5336           indicates to the C program that <ndbm.h> exists and should be
5337           included.
5338
5339       "i_netdb"
5340           From i_netdb.U:
5341
5342           This variable conditionally defines the "I_NETDB" symbol, and
5343           indicates whether a C program should include <netdb.h>.
5344
5345       "i_neterrno"
5346           From i_neterrno.U:
5347
5348           This variable conditionally defines the "I_NET_ERRNO" symbol, which
5349           indicates to the C program that <net/errno.h> exists and should be
5350           included.
5351
5352       "i_netinettcp"
5353           From i_netinettcp.U:
5354
5355           This variable conditionally defines the "I_NETINET_TCP" symbol, and
5356           indicates whether a C program should include <netinet/tcp.h>.
5357
5358       "i_niin"
5359           From i_niin.U:
5360
5361           This variable conditionally defines "I_NETINET_IN", which indicates
5362           to the C program that it should include <netinet/in.h>. Otherwise,
5363           you may try <sys/in.h>.
5364
5365       "i_poll"
5366           From i_poll.U:
5367
5368           This variable conditionally defines the "I_POLL" symbol, and
5369           indicates whether a C program should include <poll.h>.
5370
5371       "i_prot"
5372           From i_prot.U:
5373
5374           This variable conditionally defines the "I_PROT" symbol, and
5375           indicates whether a C program should include <prot.h>.
5376
5377       "i_pthread"
5378           From i_pthread.U:
5379
5380           This variable conditionally defines the "I_PTHREAD" symbol, and
5381           indicates whether a C program should include <pthread.h>.
5382
5383       "i_pwd"
5384           From i_pwd.U:
5385
5386           This variable conditionally defines "I_PWD", which indicates to the
5387           C program that it should include <pwd.h>.
5388
5389       "i_quadmath"
5390           From i_quadmath.U:
5391
5392           This variable conditionally defines "I_QUADMATH", which indicates
5393           to the C program that it should include <quadmath.h>.
5394
5395       "i_rpcsvcdbm"
5396           From i_dbm.U:
5397
5398           This variable conditionally defines the "I_RPCSVC_DBM" symbol,
5399           which indicates to the C program that <rpcsvc/dbm.h> exists and
5400           should be included.  Some System V systems might need this instead
5401           of <dbm.h>.
5402
5403       "i_sgtty"
5404           From i_termio.U:
5405
5406           This variable conditionally defines the "I_SGTTY" symbol, which
5407           indicates to the C program that it should include <sgtty.h> rather
5408           than <termio.h>.
5409
5410       "i_shadow"
5411           From i_shadow.U:
5412
5413           This variable conditionally defines the "I_SHADOW" symbol, and
5414           indicates whether a C program should include <shadow.h>.
5415
5416       "i_socks"
5417           From i_socks.U:
5418
5419           This variable conditionally defines the "I_SOCKS" symbol, and
5420           indicates whether a C program should include <socks.h>.
5421
5422       "i_stdbool"
5423           From i_stdbool.U:
5424
5425           This variable conditionally defines the "I_STDBOOL" symbol, which
5426           indicates to the C program that <stdbool.h> exists and should be
5427           included.
5428
5429       "i_stdint"
5430           From i_stdint.U:
5431
5432           This variable conditionally defines the "I_STDINT" symbol, which
5433           indicates to the C program that <stdint.h> exists and should be
5434           included.
5435
5436       "i_stdlib"
5437           From i_stdlib.U:
5438
5439           This variable unconditionally defines the "I_STDLIB" symbol.
5440
5441       "i_sunmath"
5442           From i_sunmath.U:
5443
5444           This variable conditionally defines the "I_SUNMATH" symbol, and
5445           indicates whether a C program should include <sunmath.h>.
5446
5447       "i_sysaccess"
5448           From i_sysaccess.U:
5449
5450           This variable conditionally defines the "I_SYS_ACCESS" symbol, and
5451           indicates whether a C program should include <sys/access.h>.
5452
5453       "i_sysdir"
5454           From i_sysdir.U:
5455
5456           This variable conditionally defines the "I_SYS_DIR" symbol, and
5457           indicates whether a C program should include <sys/dir.h>.
5458
5459       "i_sysfile"
5460           From i_sysfile.U:
5461
5462           This variable conditionally defines the "I_SYS_FILE" symbol, and
5463           indicates whether a C program should include <sys/file.h> to get
5464           "R_OK" and friends.
5465
5466       "i_sysfilio"
5467           From i_sysioctl.U:
5468
5469           This variable conditionally defines the "I_SYS_FILIO" symbol, which
5470           indicates to the C program that <sys/filio.h> exists and should be
5471           included in preference to <sys/ioctl.h>.
5472
5473       "i_sysin"
5474           From i_niin.U:
5475
5476           This variable conditionally defines "I_SYS_IN", which indicates to
5477           the C program that it should include <sys/in.h> instead of
5478           <netinet/in.h>.
5479
5480       "i_sysioctl"
5481           From i_sysioctl.U:
5482
5483           This variable conditionally defines the "I_SYS_IOCTL" symbol, which
5484           indicates to the C program that <sys/ioctl.h> exists and should be
5485           included.
5486
5487       "i_syslog"
5488           From i_syslog.U:
5489
5490           This variable conditionally defines the "I_SYSLOG" symbol, and
5491           indicates whether a C program should include <syslog.h>.
5492
5493       "i_sysmman"
5494           From i_sysmman.U:
5495
5496           This variable conditionally defines the "I_SYS_MMAN" symbol, and
5497           indicates whether a C program should include <sys/mman.h>.
5498
5499       "i_sysmode"
5500           From i_sysmode.U:
5501
5502           This variable conditionally defines the "I_SYSMODE" symbol, and
5503           indicates whether a C program should include <sys/mode.h>.
5504
5505       "i_sysmount"
5506           From i_sysmount.U:
5507
5508           This variable conditionally defines the "I_SYSMOUNT" symbol, and
5509           indicates whether a C program should include <sys/mount.h>.
5510
5511       "i_sysndir"
5512           From i_sysndir.U:
5513
5514           This variable conditionally defines the "I_SYS_NDIR" symbol, and
5515           indicates whether a C program should include <sys/ndir.h>.
5516
5517       "i_sysparam"
5518           From i_sysparam.U:
5519
5520           This variable conditionally defines the "I_SYS_PARAM" symbol, and
5521           indicates whether a C program should include <sys/param.h>.
5522
5523       "i_syspoll"
5524           From i_syspoll.U:
5525
5526           This variable conditionally defines the "I_SYS_POLL" symbol, which
5527           indicates to the C program that it should include <sys/poll.h>.
5528
5529       "i_sysresrc"
5530           From i_sysresrc.U:
5531
5532           This variable conditionally defines the "I_SYS_RESOURCE" symbol,
5533           and indicates whether a C program should include <sys/resource.h>.
5534
5535       "i_syssecrt"
5536           From i_syssecrt.U:
5537
5538           This variable conditionally defines the "I_SYS_SECURITY" symbol,
5539           and indicates whether a C program should include <sys/security.h>.
5540
5541       "i_sysselct"
5542           From i_sysselct.U:
5543
5544           This variable conditionally defines "I_SYS_SELECT", which indicates
5545           to the C program that it should include <sys/select.h> in order to
5546           get the definition of struct timeval.
5547
5548       "i_syssockio"
5549           From i_sysioctl.U:
5550
5551           This variable conditionally defines "I_SYS_SOCKIO" to indicate to
5552           the C program that socket ioctl codes may be found in
5553           <sys/sockio.h> instead of <sys/ioctl.h>.
5554
5555       "i_sysstat"
5556           From i_sysstat.U:
5557
5558           This variable conditionally defines the "I_SYS_STAT" symbol, and
5559           indicates whether a C program should include <sys/stat.h>.
5560
5561       "i_sysstatfs"
5562           From i_sysstatfs.U:
5563
5564           This variable conditionally defines the "I_SYSSTATFS" symbol, and
5565           indicates whether a C program should include <sys/statfs.h>.
5566
5567       "i_sysstatvfs"
5568           From i_sysstatvfs.U:
5569
5570           This variable conditionally defines the "I_SYSSTATVFS" symbol, and
5571           indicates whether a C program should include <sys/statvfs.h>.
5572
5573       "i_systime"
5574           From i_time.U:
5575
5576           This variable conditionally defines "I_SYS_TIME", which indicates
5577           to the C program that it should include <sys/time.h>.
5578
5579       "i_systimek"
5580           From i_time.U:
5581
5582           This variable conditionally defines "I_SYS_TIME_KERNEL", which
5583           indicates to the C program that it should include <sys/time.h> with
5584           "KERNEL" defined.
5585
5586       "i_systimes"
5587           From i_systimes.U:
5588
5589           This variable conditionally defines the "I_SYS_TIMES" symbol, and
5590           indicates whether a C program should include <sys/times.h>.
5591
5592       "i_systypes"
5593           From i_systypes.U:
5594
5595           This variable conditionally defines the "I_SYS_TYPES" symbol, and
5596           indicates whether a C program should include <sys/types.h>.
5597
5598       "i_sysuio"
5599           From i_sysuio.U:
5600
5601           This variable conditionally defines the "I_SYSUIO" symbol, and
5602           indicates whether a C program should include <sys/uio.h>.
5603
5604       "i_sysun"
5605           From i_sysun.U:
5606
5607           This variable conditionally defines "I_SYS_UN", which indicates to
5608           the C program that it should include <sys/un.h> to get "UNIX"
5609           domain socket definitions.
5610
5611       "i_sysutsname"
5612           From i_sysutsname.U:
5613
5614           This variable conditionally defines the "I_SYSUTSNAME" symbol, and
5615           indicates whether a C program should include <sys/utsname.h>.
5616
5617       "i_sysvfs"
5618           From i_sysvfs.U:
5619
5620           This variable conditionally defines the "I_SYSVFS" symbol, and
5621           indicates whether a C program should include <sys/vfs.h>.
5622
5623       "i_syswait"
5624           From i_syswait.U:
5625
5626           This variable conditionally defines "I_SYS_WAIT", which indicates
5627           to the C program that it should include <sys/wait.h>.
5628
5629       "i_termio"
5630           From i_termio.U:
5631
5632           This variable conditionally defines the "I_TERMIO" symbol, which
5633           indicates to the C program that it should include <termio.h> rather
5634           than <sgtty.h>.
5635
5636       "i_termios"
5637           From i_termio.U:
5638
5639           This variable conditionally defines the "I_TERMIOS" symbol, which
5640           indicates to the C program that the "POSIX" <termios.h> file is to
5641           be included.
5642
5643       "i_time"
5644           From i_time.U:
5645
5646           This variable unconditionally defines "I_TIME", which indicates to
5647           the C program that it should include <time.h>.
5648
5649       "i_unistd"
5650           From i_unistd.U:
5651
5652           This variable conditionally defines the "I_UNISTD" symbol, and
5653           indicates whether a C program should include <unistd.h>.
5654
5655       "i_ustat"
5656           From i_ustat.U:
5657
5658           This variable conditionally defines the "I_USTAT" symbol, and
5659           indicates whether a C program should include <ustat.h>.
5660
5661       "i_utime"
5662           From i_utime.U:
5663
5664           This variable conditionally defines the "I_UTIME" symbol, and
5665           indicates whether a C program should include <utime.h>.
5666
5667       "i_vfork"
5668           From i_vfork.U:
5669
5670           This variable conditionally defines the "I_VFORK" symbol, and
5671           indicates whether a C program should include vfork.h.
5672
5673       "i_wchar"
5674           From i_wchar.U:
5675
5676           This variable conditionally defines the "I_WCHAR" symbol, that
5677           indicates whether a C program may include <wchar.h>.
5678
5679       "i_wctype"
5680           From i_wctype.U:
5681
5682           This variable conditionally defines the "I_WCTYPE" symbol, that
5683           indicates whether a C program may include <wctype.h>.
5684
5685       "i_xlocale"
5686           From d_newlocale.U:
5687
5688           This symbol, if defined, indicates to the C program that the header
5689           xlocale.h is available.  See also xlocale_needed.
5690
5691       "ignore_versioned_solibs"
5692           From libs.U:
5693
5694           This variable should be non-empty if non-versioned shared libraries
5695           (libfoo.so.x.y) are to be ignored (because they cannot be linked
5696           against).
5697
5698       "inc_version_list"
5699           From inc_version_list.U:
5700
5701           This variable specifies the list of subdirectories in over which
5702           perl.c:incpush() and lib/lib.pm will automatically search when
5703           adding directories to @"INC".  The elements in the list are
5704           separated by spaces.  This is only useful if you have a perl
5705           library directory tree structured like the default one.  See
5706           "INSTALL" for how this works.  The versioned site_perl directory
5707           was introduced in 5.005, so that is the lowest possible value.
5708
5709           This list includes architecture-dependent directories back to
5710           version $api_versionstring (e.g. 5.5.640) and architecture-
5711           independent directories all the way back to 5.005.
5712
5713       "inc_version_list_init"
5714           From inc_version_list.U:
5715
5716           This variable holds the same list as inc_version_list, but each
5717           item is enclosed in double quotes and separated by commas, suitable
5718           for use in the "PERL_INC_VERSION_LIST" initialization.
5719
5720       "incpath"
5721           From usrinc.U:
5722
5723           This variable must precede the normal include path to get the right
5724           one, as in $incpath/usr/include or $incpath/usr/lib.  Value can be
5725           "" or /bsd43 on mips.
5726
5727       "incpth"
5728           From libpth.U:
5729
5730           This variable must precede the normal include path to get the right
5731           one, as in $incpath/usr/include or $incpath/usr/lib.  Value can be
5732           "" or /bsd43 on mips.
5733
5734       "inews"
5735           From Loc.U:
5736
5737           This variable is defined but not used by Configure.  The value is
5738           the empty string and is not useful.
5739
5740       "initialinstalllocation"
5741           From bin.U:
5742
5743           When userelocatableinc is true, this variable holds the location
5744           that make install should copy the perl binary to, with all the run-
5745           time relocatable paths calculated from this at install time.  When
5746           used, it is initialized to the original value of binexp, and then
5747           binexp is set to .../, as the other binaries are found relative to
5748           the perl binary.
5749
5750       "installarchlib"
5751           From archlib.U:
5752
5753           This variable is really the same as archlibexp but may differ on
5754           those systems using "AFS". For extra portability, only this
5755           variable should be used in makefiles.
5756
5757       "installbin"
5758           From bin.U:
5759
5760           This variable is the same as binexp unless "AFS" is running in
5761           which case the user is explicitly prompted for it. This variable
5762           should always be used in your makefiles for maximum portability.
5763
5764       "installhtml1dir"
5765           From html1dir.U:
5766
5767           This variable is really the same as html1direxp, unless you are
5768           using a different installprefix.  For extra portability, you should
5769           only use this variable within your makefiles.
5770
5771       "installhtml3dir"
5772           From html3dir.U:
5773
5774           This variable is really the same as html3direxp, unless you are
5775           using a different installprefix.  For extra portability, you should
5776           only use this variable within your makefiles.
5777
5778       "installman1dir"
5779           From man1dir.U:
5780
5781           This variable is really the same as man1direxp, unless you are
5782           using "AFS" in which case it points to the read/write location
5783           whereas man1direxp only points to the read-only access location.
5784           For extra portability, you should only use this variable within
5785           your makefiles.
5786
5787       "installman3dir"
5788           From man3dir.U:
5789
5790           This variable is really the same as man3direxp, unless you are
5791           using "AFS" in which case it points to the read/write location
5792           whereas man3direxp only points to the read-only access location.
5793           For extra portability, you should only use this variable within
5794           your makefiles.
5795
5796       "installprefix"
5797           From installprefix.U:
5798
5799           This variable holds the name of the directory below which "make
5800           install" will install the package.  For most users, this is the
5801           same as prefix.  However, it is useful for installing the software
5802           into a different (usually temporary) location after which it can be
5803           bundled up and moved somehow to the final location specified by
5804           prefix.
5805
5806       "installprefixexp"
5807           From installprefix.U:
5808
5809           This variable holds the full absolute path of installprefix with
5810           all ~-expansion done.
5811
5812       "installprivlib"
5813           From privlib.U:
5814
5815           This variable is really the same as privlibexp but may differ on
5816           those systems using "AFS". For extra portability, only this
5817           variable should be used in makefiles.
5818
5819       "installscript"
5820           From scriptdir.U:
5821
5822           This variable is usually the same as scriptdirexp, unless you are
5823           on a system running "AFS", in which case they may differ slightly.
5824           You should always use this variable within your makefiles for
5825           portability.
5826
5827       "installsitearch"
5828           From sitearch.U:
5829
5830           This variable is really the same as sitearchexp but may differ on
5831           those systems using "AFS". For extra portability, only this
5832           variable should be used in makefiles.
5833
5834       "installsitebin"
5835           From sitebin.U:
5836
5837           This variable is usually the same as sitebinexp, unless you are on
5838           a system running "AFS", in which case they may differ slightly. You
5839           should always use this variable within your makefiles for
5840           portability.
5841
5842       "installsitehtml1dir"
5843           From sitehtml1dir.U:
5844
5845           This variable is really the same as sitehtml1direxp, unless you are
5846           using "AFS" in which case it points to the read/write location
5847           whereas html1direxp only points to the read-only access location.
5848           For extra portability, you should only use this variable within
5849           your makefiles.
5850
5851       "installsitehtml3dir"
5852           From sitehtml3dir.U:
5853
5854           This variable is really the same as sitehtml3direxp, unless you are
5855           using "AFS" in which case it points to the read/write location
5856           whereas html3direxp only points to the read-only access location.
5857           For extra portability, you should only use this variable within
5858           your makefiles.
5859
5860       "installsitelib"
5861           From sitelib.U:
5862
5863           This variable is really the same as sitelibexp but may differ on
5864           those systems using "AFS". For extra portability, only this
5865           variable should be used in makefiles.
5866
5867       "installsiteman1dir"
5868           From siteman1dir.U:
5869
5870           This variable is really the same as siteman1direxp, unless you are
5871           using "AFS" in which case it points to the read/write location
5872           whereas man1direxp only points to the read-only access location.
5873           For extra portability, you should only use this variable within
5874           your makefiles.
5875
5876       "installsiteman3dir"
5877           From siteman3dir.U:
5878
5879           This variable is really the same as siteman3direxp, unless you are
5880           using "AFS" in which case it points to the read/write location
5881           whereas man3direxp only points to the read-only access location.
5882           For extra portability, you should only use this variable within
5883           your makefiles.
5884
5885       "installsitescript"
5886           From sitescript.U:
5887
5888           This variable is usually the same as sitescriptexp, unless you are
5889           on a system running "AFS", in which case they may differ slightly.
5890           You should always use this variable within your makefiles for
5891           portability.
5892
5893       "installstyle"
5894           From installstyle.U:
5895
5896           This variable describes the "style" of the perl installation.  This
5897           is intended to be useful for tools that need to manipulate entire
5898           perl distributions.  Perl itself doesn't use this to find its
5899           libraries -- the library directories are stored directly in
5900           Config.pm.  Currently, there are only two styles:  "lib" and
5901           lib/perl5.  The default library locations (e.g. privlib, sitelib)
5902           are either $prefix/lib or $prefix/lib/perl5.  The former is useful
5903           if $prefix is a directory dedicated to perl (e.g. /opt/perl), while
5904           the latter is useful if $prefix is shared by many packages, e.g. if
5905           $prefix=/usr/local.
5906
5907           Unfortunately, while this "style" variable is used to set defaults
5908           for all three directory hierarchies (core, vendor, and site), there
5909           is no guarantee that the same style is actually appropriate for all
5910           those directories.  For example, $prefix might be /opt/perl, but
5911           $siteprefix might be /usr/local.  (Perhaps, in retrospect, the
5912           "lib" style should never have been supported, but it did seem like
5913           a nice idea at the time.)
5914
5915           The situation is even less clear for tools such as MakeMaker that
5916           can be used to install additional modules into non-standard places.
5917           For example, if a user intends to install a module into a private
5918           directory (perhaps by setting "PREFIX" on the Makefile.PL command
5919           line), then there is no reason to assume that the Configure-time
5920           $installstyle setting will be relevant for that "PREFIX".
5921
5922           This may later be extended to include other information, so be
5923           careful with pattern-matching on the results.
5924
5925           For compatibility with perl5.005 and earlier, the default setting
5926           is based on whether or not $prefix contains the string "perl".
5927
5928       "installusrbinperl"
5929           From instubperl.U:
5930
5931           This variable tells whether Perl should be installed also as
5932           /usr/bin/perl in addition to $installbin/perl
5933
5934       "installvendorarch"
5935           From vendorarch.U:
5936
5937           This variable is really the same as vendorarchexp but may differ on
5938           those systems using "AFS". For extra portability, only this
5939           variable should be used in makefiles.
5940
5941       "installvendorbin"
5942           From vendorbin.U:
5943
5944           This variable is really the same as vendorbinexp but may differ on
5945           those systems using "AFS". For extra portability, only this
5946           variable should be used in makefiles.
5947
5948       "installvendorhtml1dir"
5949           From vendorhtml1dir.U:
5950
5951           This variable is really the same as vendorhtml1direxp but may
5952           differ on those systems using "AFS". For extra portability, only
5953           this variable should be used in makefiles.
5954
5955       "installvendorhtml3dir"
5956           From vendorhtml3dir.U:
5957
5958           This variable is really the same as vendorhtml3direxp but may
5959           differ on those systems using "AFS". For extra portability, only
5960           this variable should be used in makefiles.
5961
5962       "installvendorlib"
5963           From vendorlib.U:
5964
5965           This variable is really the same as vendorlibexp but may differ on
5966           those systems using "AFS". For extra portability, only this
5967           variable should be used in makefiles.
5968
5969       "installvendorman1dir"
5970           From vendorman1dir.U:
5971
5972           This variable is really the same as vendorman1direxp but may differ
5973           on those systems using "AFS". For extra portability, only this
5974           variable should be used in makefiles.
5975
5976       "installvendorman3dir"
5977           From vendorman3dir.U:
5978
5979           This variable is really the same as vendorman3direxp but may differ
5980           on those systems using "AFS". For extra portability, only this
5981           variable should be used in makefiles.
5982
5983       "installvendorscript"
5984           From vendorscript.U:
5985
5986           This variable is really the same as vendorscriptexp but may differ
5987           on those systems using "AFS". For extra portability, only this
5988           variable should be used in makefiles.
5989
5990       "intsize"
5991           From intsize.U:
5992
5993           This variable contains the value of the "INTSIZE" symbol, which
5994           indicates to the C program how many bytes there are in an int.
5995
5996       "issymlink"
5997           From issymlink.U:
5998
5999           This variable holds the test command to test for a symbolic link
6000           (if they are supported).  Typical values include "test -h" and
6001           "test -L".
6002
6003       "ivdformat"
6004           From perlxvf.U:
6005
6006           This variable contains the format string used for printing a Perl
6007           "IV" as a signed decimal integer.
6008
6009       "ivsize"
6010           From perlxv.U:
6011
6012           This variable is the size of an "IV" in bytes.
6013
6014       "ivtype"
6015           From perlxv.U:
6016
6017           This variable contains the C type used for Perl's "IV".
6018
6019   k
6020       "known_extensions"
6021           From Extensions.U:
6022
6023           This variable holds a list of all extensions (both "XS" and non-xs)
6024           included in the package source distribution.  This information is
6025           only really of use during the Perl build, as the list makes no
6026           distinction between extensions which were build and installed, and
6027           those which where not.  See "extensions" for the list of extensions
6028           actually built and available.
6029
6030       "ksh"
6031           From Loc.U:
6032
6033           This variable is defined but not used by Configure.  The value is
6034           the empty string and is not useful.
6035
6036   l
6037       "ld"
6038           From dlsrc.U:
6039
6040           This variable indicates the program to be used to link libraries
6041           for dynamic loading.  On some systems, it is "ld".  On "ELF"
6042           systems, it should be $cc.  Mostly, we'll try to respect the hint
6043           file setting.
6044
6045       "ld_can_script"
6046           From dlsrc.U:
6047
6048           This variable shows if the loader accepts scripts in the form of
6049           -Wl,--version-script=ld.script. This is currently only supported
6050           for "GNU" ld on "ELF" in dynamic loading builds.
6051
6052       "lddlflags"
6053           From dlsrc.U:
6054
6055           This variable contains any special flags that might need to be
6056           passed to $ld to create a shared library suitable for dynamic
6057           loading.  It is up to the makefile to use it.  For hpux, it should
6058           be "-b".  For sunos 4.1, it is empty.
6059
6060       "ldflags"
6061           From ccflags.U:
6062
6063           This variable contains any additional C loader flags desired by the
6064           user.  It is up to the Makefile to use this.
6065
6066       "ldflags_uselargefiles"
6067           From uselfs.U:
6068
6069           This variable contains the loader flags needed by large file builds
6070           and added to ldflags by hints files.
6071
6072       "ldlibpthname"
6073           From libperl.U:
6074
6075           This variable holds the name of the shared library search path,
6076           often "LD_LIBRARY_PATH".  To get an empty string, the hints file
6077           must set this to "none".
6078
6079       "less"
6080           From Loc.U:
6081
6082           This variable is used internally by Configure to determine the full
6083           pathname (if any) of the less program.  After Configure runs, the
6084           value is reset to a plain "less" and is not useful.
6085
6086       "lib_ext"
6087           From Unix.U:
6088
6089           This is an old synonym for _a.
6090
6091       "libc"
6092           From libc.U:
6093
6094           This variable contains the location of the C library.
6095
6096       "libperl"
6097           From libperl.U:
6098
6099           The perl executable is obtained by linking perlmain.c with libperl,
6100           any static extensions (usually just DynaLoader), and any other
6101           libraries needed on this system.  libperl is usually libperl.a, but
6102           can also be libperl.so.xxx if the user wishes to build a perl
6103           executable with a shared library.
6104
6105       "libpth"
6106           From libpth.U:
6107
6108           This variable holds the general path (space-separated) used to find
6109           libraries. It is intended to be used by other units.
6110
6111       "libs"
6112           From libs.U:
6113
6114           This variable holds the additional libraries we want to use.  It is
6115           up to the Makefile to deal with it.  The list can be empty.
6116
6117       "libsdirs"
6118           From libs.U:
6119
6120           This variable holds the directory names aka dirnames of the
6121           libraries we found and accepted, duplicates are removed.
6122
6123       "libsfiles"
6124           From libs.U:
6125
6126           This variable holds the filenames aka basenames of the libraries we
6127           found and accepted.
6128
6129       "libsfound"
6130           From libs.U:
6131
6132           This variable holds the full pathnames of the libraries we found
6133           and accepted.
6134
6135       "libspath"
6136           From libs.U:
6137
6138           This variable holds the directory names probed for libraries.
6139
6140       "libswanted"
6141           From Myinit.U:
6142
6143           This variable holds a list of all the libraries we want to search.
6144           The order is chosen to pick up the c library ahead of ucb or bsd
6145           libraries for SVR4.
6146
6147       "libswanted_uselargefiles"
6148           From uselfs.U:
6149
6150           This variable contains the libraries needed by large file builds
6151           and added to ldflags by hints files.  It is a space separated list
6152           of the library names without the "lib" prefix or any suffix, just
6153           like libswanted..
6154
6155       "line"
6156           From Loc.U:
6157
6158           This variable is defined but not used by Configure.  The value is
6159           the empty string and is not useful.
6160
6161       "lint"
6162           From Loc.U:
6163
6164           This variable is defined but not used by Configure.  The value is
6165           the empty string and is not useful.
6166
6167       "lkflags"
6168           From ccflags.U:
6169
6170           This variable contains any additional C partial linker flags
6171           desired by the user.  It is up to the Makefile to use this.
6172
6173       "ln"
6174           From Loc.U:
6175
6176           This variable is used internally by Configure to determine the full
6177           pathname (if any) of the ln program.  After Configure runs, the
6178           value is reset to a plain "ln" and is not useful.
6179
6180       "lns"
6181           From lns.U:
6182
6183           This variable holds the name of the command to make symbolic links
6184           (if they are supported).  It can be used in the Makefile. It is
6185           either "ln -s" or "ln"
6186
6187       "localtime_r_proto"
6188           From d_localtime_r.U:
6189
6190           This variable encodes the prototype of localtime_r.  It is zero if
6191           d_localtime_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
6192           macros of reentr.h if d_localtime_r is defined.
6193
6194       "locincpth"
6195           From ccflags.U:
6196
6197           This variable contains a list of additional directories to be
6198           searched by the compiler.  The appropriate "-I" directives will be
6199           added to ccflags.  This is intended to simplify setting local
6200           directories from the Configure command line.  It's not much, but it
6201           parallels the loclibpth stuff in libpth.U.
6202
6203       "loclibpth"
6204           From libpth.U:
6205
6206           This variable holds the paths (space-separated) used to find local
6207           libraries.  It is prepended to libpth, and is intended to be easily
6208           set from the command line.
6209
6210       "longdblinfbytes"
6211           From infnan.U:
6212
6213           This variable contains comma-separated list of hexadecimal bytes
6214           for the long double precision infinity.
6215
6216       "longdblkind"
6217           From d_longdbl.U:
6218
6219           This variable, if defined, encodes the type of a long double: 0 =
6220           double, 1 = "IEEE" 754 128-bit little endian, 2 = "IEEE" 754
6221           128-bit big endian, 3 = x86 80-bit little endian, 4 = x86 80-bit
6222           big endian, 5 = double-double 128-bit little endian, 6 = double-
6223           double 128-bit big endian, 7 = 128-bit mixed-endian double-double
6224           (64-bit LEs in "BE"), 8 = 128-bit mixed-endian double-double
6225           (64-bit BEs in "LE"), 9 = 128-bit "PDP"-style mixed-endian long
6226           doubles, -1 = unknown format.
6227
6228       "longdblmantbits"
6229           From mantbits.U:
6230
6231           This symbol, if defined, tells how many mantissa bits there are in
6232           long double precision floating point format.  Note that this can be
6233           "LDBL_MANT_DIG" minus one, since "LDBL_MANT_DIG" can include the
6234           "IEEE" 754 implicit bit.  The common x86-style 80-bit long double
6235           does not have an implicit bit.
6236
6237       "longdblnanbytes"
6238           From infnan.U:
6239
6240           This variable contains comma-separated list of hexadecimal bytes
6241           for the long double precision not-a-number.
6242
6243       "longdblsize"
6244           From d_longdbl.U:
6245
6246           This variable contains the value of the "LONG_DOUBLESIZE" symbol,
6247           which indicates to the C program how many bytes there are in a long
6248           double, if this system supports long doubles.  Note that this is
6249           sizeof(long double), which may include unused bytes.
6250
6251       "longlongsize"
6252           From d_longlong.U:
6253
6254           This variable contains the value of the "LONGLONGSIZE" symbol,
6255           which indicates to the C program how many bytes there are in a long
6256           long, if this system supports long long.
6257
6258       "longsize"
6259           From intsize.U:
6260
6261           This variable contains the value of the "LONGSIZE" symbol, which
6262           indicates to the C program how many bytes there are in a long.
6263
6264       "lp"
6265           From Loc.U:
6266
6267           This variable is defined but not used by Configure.  The value is
6268           the empty string and is not useful.
6269
6270       "lpr"
6271           From Loc.U:
6272
6273           This variable is defined but not used by Configure.  The value is
6274           the empty string and is not useful.
6275
6276       "ls"
6277           From Loc.U:
6278
6279           This variable is used internally by Configure to determine the full
6280           pathname (if any) of the ls program.  After Configure runs, the
6281           value is reset to a plain "ls" and is not useful.
6282
6283       "lseeksize"
6284           From lseektype.U:
6285
6286           This variable defines lseektype to be something like off_t, long,
6287           or whatever type is used to declare lseek offset's type in the
6288           kernel (which also appears to be lseek's return type).
6289
6290       "lseektype"
6291           From lseektype.U:
6292
6293           This variable defines lseektype to be something like off_t, long,
6294           or whatever type is used to declare lseek offset's type in the
6295           kernel (which also appears to be lseek's return type).
6296
6297   m
6298       "mail"
6299           From Loc.U:
6300
6301           This variable is defined but not used by Configure.  The value is
6302           the empty string and is not useful.
6303
6304       "mailx"
6305           From Loc.U:
6306
6307           This variable is defined but not used by Configure.  The value is
6308           the empty string and is not useful.
6309
6310       "make"
6311           From Loc.U:
6312
6313           This variable is used internally by Configure to determine the full
6314           pathname (if any) of the make program.  After Configure runs, the
6315           value is reset to a plain "make" and is not useful.
6316
6317       "make_set_make"
6318           From make.U:
6319
6320           Some versions of "make" set the variable "MAKE".  Others do not.
6321           This variable contains the string to be included in Makefile.SH so
6322           that "MAKE" is set if needed, and not if not needed.  Possible
6323           values are:
6324
6325           make_set_make="#"        # If your make program handles this for
6326           you,
6327
6328           make_set_make="MAKE=$make"    # if it doesn't.
6329
6330           This uses a comment character so that we can distinguish a "set"
6331           value (from a previous config.sh or Configure "-D" option) from an
6332           uncomputed value.
6333
6334       "mallocobj"
6335           From mallocsrc.U:
6336
6337           This variable contains the name of the malloc.o that this package
6338           generates, if that malloc.o is preferred over the system malloc.
6339           Otherwise the value is null.  This variable is intended for
6340           generating Makefiles.  See mallocsrc.
6341
6342       "mallocsrc"
6343           From mallocsrc.U:
6344
6345           This variable contains the name of the malloc.c that comes with the
6346           package, if that malloc.c is preferred over the system malloc.
6347           Otherwise the value is null.  This variable is intended for
6348           generating Makefiles.
6349
6350       "malloctype"
6351           From mallocsrc.U:
6352
6353           This variable contains the kind of ptr returned by malloc and
6354           realloc.
6355
6356       "man1dir"
6357           From man1dir.U:
6358
6359           This variable contains the name of the directory in which manual
6360           source pages are to be put.  It is the responsibility of the
6361           Makefile.SH to get the value of this into the proper command.  You
6362           must be prepared to do the ~name expansion yourself.
6363
6364       "man1direxp"
6365           From man1dir.U:
6366
6367           This variable is the same as the man1dir variable, but is filename
6368           expanded at configuration time, for convenient use in makefiles.
6369
6370       "man1ext"
6371           From man1dir.U:
6372
6373           This variable contains the extension that the manual page should
6374           have: one of "n", "l", or 1.  The Makefile must supply the ..  See
6375           man1dir.
6376
6377       "man3dir"
6378           From man3dir.U:
6379
6380           This variable contains the name of the directory in which manual
6381           source pages are to be put.  It is the responsibility of the
6382           Makefile.SH to get the value of this into the proper command.  You
6383           must be prepared to do the ~name expansion yourself.
6384
6385       "man3direxp"
6386           From man3dir.U:
6387
6388           This variable is the same as the man3dir variable, but is filename
6389           expanded at configuration time, for convenient use in makefiles.
6390
6391       "man3ext"
6392           From man3dir.U:
6393
6394           This variable contains the extension that the manual page should
6395           have: one of "n", "l", or 3.  The Makefile must supply the ..  See
6396           man3dir.
6397
6398       "mips_type"
6399           From usrinc.U:
6400
6401           This variable holds the environment type for the mips system.
6402           Possible values are "BSD 4.3" and "System V".
6403
6404       "mistrustnm"
6405           From Csym.U:
6406
6407           This variable can be used to establish a fallthrough for the cases
6408           where nm fails to find a symbol.  If usenm is false or usenm is
6409           true and mistrustnm is false, this variable has no effect.  If
6410           usenm is true and mistrustnm is "compile", a test program will be
6411           compiled to try to find any symbol that can't be located via nm
6412           lookup.  If mistrustnm is "run", the test program will be run as
6413           well as being compiled.
6414
6415       "mkdir"
6416           From Loc.U:
6417
6418           This variable is used internally by Configure to determine the full
6419           pathname (if any) of the mkdir program.  After Configure runs, the
6420           value is reset to a plain "mkdir" and is not useful.
6421
6422       "mmaptype"
6423           From d_mmap.U:
6424
6425           This symbol contains the type of pointer returned by mmap() (and
6426           simultaneously the type of the first argument).  It can be "void *"
6427           or "caddr_t".
6428
6429       "modetype"
6430           From modetype.U:
6431
6432           This variable defines modetype to be something like mode_t, int,
6433           unsigned short, or whatever type is used to declare file modes for
6434           system calls.
6435
6436       "more"
6437           From Loc.U:
6438
6439           This variable is used internally by Configure to determine the full
6440           pathname (if any) of the more program.  After Configure runs, the
6441           value is reset to a plain "more" and is not useful.
6442
6443       "multiarch"
6444           From multiarch.U:
6445
6446           This variable conditionally defines the "MULTIARCH" symbol which
6447           signifies the presence of multiplatform files.  This is normally
6448           set by hints files.
6449
6450       "mv"
6451           From Loc.U:
6452
6453           This variable is defined but not used by Configure.  The value is
6454           the empty string and is not useful.
6455
6456       "myarchname"
6457           From archname.U:
6458
6459           This variable holds the architecture name computed by Configure in
6460           a previous run. It is not intended to be perused by any user and
6461           should never be set in a hint file.
6462
6463       "mydomain"
6464           From myhostname.U:
6465
6466           This variable contains the eventual value of the "MYDOMAIN" symbol,
6467           which is the domain of the host the program is going to run on.
6468           The domain must be appended to myhostname to form a complete host
6469           name.  The dot comes with mydomain, and need not be supplied by the
6470           program.
6471
6472       "myhostname"
6473           From myhostname.U:
6474
6475           This variable contains the eventual value of the "MYHOSTNAME"
6476           symbol, which is the name of the host the program is going to run
6477           on.  The domain is not kept with hostname, but must be gotten from
6478           mydomain.  The dot comes with mydomain, and need not be supplied by
6479           the program.
6480
6481       "myuname"
6482           From Oldconfig.U:
6483
6484           The output of "uname -a" if available, otherwise the hostname.  The
6485           whole thing is then lower-cased and slashes and single quotes are
6486           removed.
6487
6488   n
6489       "n" From n.U:
6490
6491           This variable contains the "-n" flag if that is what causes the
6492           echo command to suppress newline.  Otherwise it is null.  Correct
6493           usage is $echo $n "prompt for a question: $c".
6494
6495       "need_va_copy"
6496           From need_va_copy.U:
6497
6498           This symbol, if defined, indicates that the system stores the
6499           variable argument list datatype, va_list, in a format that cannot
6500           be copied by simple assignment, so that some other means must be
6501           used when copying is required.  As such systems vary in their
6502           provision (or non-provision) of copying mechanisms, handy.h defines
6503           a platform- "independent" macro, Perl_va_copy(src, dst), to do the
6504           job.
6505
6506       "netdb_hlen_type"
6507           From netdbtype.U:
6508
6509           This variable holds the type used for the 2nd argument to
6510           gethostbyaddr().  Usually, this is int or size_t or unsigned.  This
6511           is only useful if you have gethostbyaddr(), naturally.
6512
6513       "netdb_host_type"
6514           From netdbtype.U:
6515
6516           This variable holds the type used for the 1st argument to
6517           gethostbyaddr().  Usually, this is char * or void *,  possibly with
6518           or without a const prefix.  This is only useful if you have
6519           gethostbyaddr(), naturally.
6520
6521       "netdb_name_type"
6522           From netdbtype.U:
6523
6524           This variable holds the type used for the argument to
6525           gethostbyname().  Usually, this is char * or const char *.  This is
6526           only useful if you have gethostbyname(), naturally.
6527
6528       "netdb_net_type"
6529           From netdbtype.U:
6530
6531           This variable holds the type used for the 1st argument to
6532           getnetbyaddr().  Usually, this is int or long.  This is only useful
6533           if you have getnetbyaddr(), naturally.
6534
6535       "nm"
6536           From Loc.U:
6537
6538           This variable is used internally by Configure to determine the full
6539           pathname (if any) of the nm program.  After Configure runs, the
6540           value is reset to a plain "nm" and is not useful.
6541
6542       "nm_opt"
6543           From usenm.U:
6544
6545           This variable holds the options that may be necessary for nm.
6546
6547       "nm_so_opt"
6548           From usenm.U:
6549
6550           This variable holds the options that may be necessary for nm to
6551           work on a shared library but that can not be used on an archive
6552           library.  Currently, this is only used by Linux, where nm --dynamic
6553           is *required* to get symbols from an "ELF" library which has been
6554           stripped, but nm --dynamic is *fatal* on an archive library.  Maybe
6555           Linux should just always set usenm=false.
6556
6557       "nonxs_ext"
6558           From Extensions.U:
6559
6560           This variable holds a list of all non-xs extensions built and
6561           installed by the package.  By default, all non-xs extensions
6562           distributed will be built, with the exception of platform-specific
6563           extensions (currently only one "VMS" specific extension).
6564
6565       "nroff"
6566           From Loc.U:
6567
6568           This variable is used internally by Configure to determine the full
6569           pathname (if any) of the nroff program.  After Configure runs, the
6570           value is reset to a plain "nroff" and is not useful.
6571
6572       "nv_overflows_integers_at"
6573           From perlxv.U:
6574
6575           This variable gives the largest integer value that NVs can hold as
6576           a constant floating point expression.  If it could not be
6577           determined, it holds the value 0.
6578
6579       "nv_preserves_uv_bits"
6580           From perlxv.U:
6581
6582           This variable indicates how many of bits type uvtype a variable
6583           nvtype can preserve.
6584
6585       "nveformat"
6586           From perlxvf.U:
6587
6588           This variable contains the format string used for printing a Perl
6589           "NV" using %e-ish floating point format.
6590
6591       "nvEUformat"
6592           From perlxvf.U:
6593
6594           This variable contains the format string used for printing a Perl
6595           "NV" using %E-ish floating point format.
6596
6597       "nvfformat"
6598           From perlxvf.U:
6599
6600           This variable contains the format string used for printing a Perl
6601           "NV" using %f-ish floating point format.
6602
6603       "nvFUformat"
6604           From perlxvf.U:
6605
6606           This variable contains the format string used for printing a Perl
6607           "NV" using %F-ish floating point format.
6608
6609       "nvgformat"
6610           From perlxvf.U:
6611
6612           This variable contains the format string used for printing a Perl
6613           "NV" using %g-ish floating point format.
6614
6615       "nvGUformat"
6616           From perlxvf.U:
6617
6618           This variable contains the format string used for printing a Perl
6619           "NV" using %G-ish floating point format.
6620
6621       "nvmantbits"
6622           From mantbits.U:
6623
6624           This variable tells how many bits the mantissa of a Perl "NV" has,
6625           not including the possible implicit bit.
6626
6627       "nvsize"
6628           From perlxv.U:
6629
6630           This variable is the size of a Perl "NV" in bytes.  Note that some
6631           floating point formats have unused bytes.
6632
6633       "nvtype"
6634           From perlxv.U:
6635
6636           This variable contains the C type used for Perl's "NV".
6637
6638   o
6639       "o_nonblock"
6640           From nblock_io.U:
6641
6642           This variable bears the symbol value to be used during open() or
6643           fcntl() to turn on non-blocking I/O for a file descriptor. If you
6644           wish to switch between blocking and non-blocking, you may try
6645           ioctl("FIOSNBIO") instead, but that is only supported by some
6646           devices.
6647
6648       "obj_ext"
6649           From Unix.U:
6650
6651           This is an old synonym for _o.
6652
6653       "old_pthread_create_joinable"
6654           From d_pthrattrj.U:
6655
6656           This variable defines the constant to use for creating joinable
6657           (aka undetached) pthreads.  Unused if pthread.h defines
6658           "PTHREAD_CREATE_JOINABLE".  If used, possible values are
6659           "PTHREAD_CREATE_UNDETACHED" and "__UNDETACHED".
6660
6661       "optimize"
6662           From ccflags.U:
6663
6664           This variable contains any optimizer/debugger flag that should be
6665           used.  It is up to the Makefile to use it.
6666
6667       "orderlib"
6668           From orderlib.U:
6669
6670           This variable is "true" if the components of libraries must be
6671           ordered (with `lorder $* | tsort`) before placing them in an
6672           archive.  Set to "false" if ranlib or ar can generate random
6673           libraries.
6674
6675       "osname"
6676           From Oldconfig.U:
6677
6678           This variable contains the operating system name (e.g. sunos,
6679           solaris, hpux, etc.).  It can be useful later on for setting
6680           defaults.  Any spaces are replaced with underscores.  It is set to
6681           a null string if we can't figure it out.
6682
6683       "osvers"
6684           From Oldconfig.U:
6685
6686           This variable contains the operating system version (e.g.  4.1.3,
6687           5.2, etc.).  It is primarily used for helping select an appropriate
6688           hints file, but might be useful elsewhere for setting defaults.  It
6689           is set to '' if we can't figure it out.  We try to be flexible
6690           about how much of the version number to keep, e.g. if 4.1.1, 4.1.2,
6691           and 4.1.3 are essentially the same for this package, hints files
6692           might just be os_4.0 or os_4.1, etc., not keeping separate files
6693           for each little release.
6694
6695       "otherlibdirs"
6696           From otherlibdirs.U:
6697
6698           This variable contains a colon-separated set of paths for the perl
6699           binary to search for additional library files or modules.  These
6700           directories will be tacked to the end of @"INC".  Perl will
6701           automatically search below each path for version- and architecture-
6702           specific directories.  See inc_version_list for more details.  A
6703           value of " " means "none" and is used to preserve this value for
6704           the next run through Configure.
6705
6706   p
6707       "package"
6708           From package.U:
6709
6710           This variable contains the name of the package being constructed.
6711           It is primarily intended for the use of later Configure units.
6712
6713       "pager"
6714           From pager.U:
6715
6716           This variable contains the name of the preferred pager on the
6717           system.  Usual values are (the full pathnames of) more, less, pg,
6718           or cat.
6719
6720       "passcat"
6721           From nis.U:
6722
6723           This variable contains a command that produces the text of the
6724           /etc/passwd file.  This is normally "cat /etc/passwd", but can be
6725           "ypcat passwd" when "NIS" is used.  On some systems, such as os390,
6726           there may be no equivalent command, in which case this variable is
6727           unset.
6728
6729       "patchlevel"
6730           From patchlevel.U:
6731
6732           The patchlevel level of this package.  The value of patchlevel
6733           comes from the patchlevel.h file.  In a version number such as
6734           5.6.1, this is the 6.  In patchlevel.h, this is referred to as
6735           "PERL_VERSION".
6736
6737       "path_sep"
6738           From Unix.U:
6739
6740           This is an old synonym for p_ in Head.U, the character used to
6741           separate elements in the command shell search "PATH".
6742
6743       "perl"
6744           From Loc.U:
6745
6746           This variable is used internally by Configure to determine the full
6747           pathname (if any) of the perl program.  After Configure runs, the
6748           value is reset to a plain "perl" and is not useful.
6749
6750       "perl5"
6751           From perl5.U:
6752
6753           This variable contains the full path (if any) to a previously
6754           installed perl5.005 or later suitable for running the script to
6755           determine inc_version_list.
6756
6757   P
6758       "PERL_API_REVISION"
6759           From patchlevel.h:
6760
6761           This number describes the earliest compatible "PERL_REVISION" of
6762           Perl ("compatibility" here being defined as sufficient binary/"API"
6763           compatibility to run "XS" code built with the older version).
6764           Normally this does not change across maintenance releases.  Please
6765           read the comment in patchlevel.h.
6766
6767       "PERL_API_SUBVERSION"
6768           From patchlevel.h:
6769
6770           This number describes the earliest compatible "PERL_SUBVERSION" of
6771           Perl ("compatibility" here being defined as sufficient binary/"API"
6772           compatibility to run "XS" code built with the older version).
6773           Normally this does not change across maintenance releases.  Please
6774           read the comment in patchlevel.h.
6775
6776       "PERL_API_VERSION"
6777           From patchlevel.h:
6778
6779           This number describes the earliest compatible "PERL_VERSION" of
6780           Perl ("compatibility" here being defined as sufficient binary/"API"
6781           compatibility to run "XS" code built with the older version).
6782           Normally this does not change across maintenance releases.  Please
6783           read the comment in patchlevel.h.
6784
6785       "PERL_CONFIG_SH"
6786           From Oldsyms.U:
6787
6788           This is set to "true" in config.sh so that a shell script sourcing
6789           config.sh can tell if it has been sourced already.
6790
6791       "PERL_PATCHLEVEL"
6792           From Oldsyms.U:
6793
6794           This symbol reflects the patchlevel, if available. Will usually
6795           come from the .patch file, which is available when the perl source
6796           tree was fetched with rsync.
6797
6798       "perl_patchlevel"
6799           From patchlevel.U:
6800
6801           This is the Perl patch level, a numeric change identifier, as
6802           defined by whichever source code maintenance system is used to
6803           maintain the patches; currently Perforce.  It does not correlate
6804           with the Perl version numbers or the maintenance versus development
6805           dichotomy except by also being increasing.
6806
6807       "PERL_REVISION"
6808           From Oldsyms.U:
6809
6810           In a Perl version number such as 5.6.2, this is the 5.  This value
6811           is manually set in patchlevel.h
6812
6813       "perl_static_inline"
6814           From d_static_inline.U:
6815
6816           This variable defines the "PERL_STATIC_INLINE" symbol to the best-
6817           guess incantation to use for static inline functions.
6818           Possibilities include static inline       (c99) static __inline__
6819           (gcc -ansi) static __inline     ("MSVC") static _inline      (older
6820           "MSVC") static              (c89 compilers)
6821
6822       "PERL_SUBVERSION"
6823           From Oldsyms.U:
6824
6825           In a Perl version number such as 5.6.2, this is the 2.  Values
6826           greater than 50 represent potentially unstable development
6827           subversions.  This value is manually set in patchlevel.h
6828
6829       "perl_thread_local"
6830           From d_thread_local.U:
6831
6832           This variable gives the value for the "PERL_THREAD_LOCAL" symbol
6833           (when defined), which gives a linkage specification for thread-
6834           local storage.
6835
6836       "PERL_VERSION"
6837           From Oldsyms.U:
6838
6839           In a Perl version number such as 5.6.2, this is the 6.  This value
6840           is manually set in patchlevel.h
6841
6842       "perladmin"
6843           From perladmin.U:
6844
6845           Electronic mail address of the perl5 administrator.
6846
6847       "perllibs"
6848           From End.U:
6849
6850           The list of libraries needed by Perl only (any libraries needed by
6851           extensions only will by dropped, if using dynamic loading).
6852
6853       "perlpath"
6854           From perlpath.U:
6855
6856           This variable contains the eventual value of the "PERLPATH" symbol,
6857           which contains the name of the perl interpreter to be used in shell
6858           scripts and in the "eval "exec"" idiom.  This variable is not
6859           necessarily the pathname of the file containing the perl
6860           interpreter; you must append the executable extension (_exe) if it
6861           is not already present.  Note that Perl code that runs during the
6862           Perl build process cannot reference this variable, as Perl may not
6863           have been installed, or even if installed, may be a different
6864           version of Perl.
6865
6866       "pg"
6867           From Loc.U:
6868
6869           This variable is used internally by Configure to determine the full
6870           pathname (if any) of the pg program.  After Configure runs, the
6871           value is reset to a plain "pg" and is not useful.
6872
6873       "phostname"
6874           From myhostname.U:
6875
6876           This variable contains the eventual value of the "PHOSTNAME"
6877           symbol, which is a command that can be fed to popen() to get the
6878           host name.  The program should probably not presume that the domain
6879           is or isn't there already.
6880
6881       "pidtype"
6882           From pidtype.U:
6883
6884           This variable defines "PIDTYPE" to be something like pid_t, int,
6885           ushort, or whatever type is used to declare process ids in the
6886           kernel.
6887
6888       "plibpth"
6889           From libpth.U:
6890
6891           Holds the private path used by Configure to find out the libraries.
6892           Its value is prepend to libpth. This variable takes care of special
6893           machines, like the mips.  Usually, it should be empty.
6894
6895       "pmake"
6896           From Loc.U:
6897
6898           This variable is defined but not used by Configure.  The value is
6899           the empty string and is not useful.
6900
6901       "pr"
6902           From Loc.U:
6903
6904           This variable is defined but not used by Configure.  The value is
6905           the empty string and is not useful.
6906
6907       "prefix"
6908           From prefix.U:
6909
6910           This variable holds the name of the directory below which the user
6911           will install the package.  Usually, this is /usr/local, and
6912           executables go in /usr/local/bin, library stuff in /usr/local/lib,
6913           man pages in /usr/local/man, etc.  It is only used to set defaults
6914           for things in bin.U, mansrc.U, privlib.U, or scriptdir.U.
6915
6916       "prefixexp"
6917           From prefix.U:
6918
6919           This variable holds the full absolute path of the directory below
6920           which the user will install the package.  Derived from prefix.
6921
6922       "privlib"
6923           From privlib.U:
6924
6925           This variable contains the eventual value of the "PRIVLIB" symbol,
6926           which is the name of the private library for this package.  It may
6927           have a ~ on the front. It is up to the makefile to eventually
6928           create this directory while performing installation (with ~
6929           substitution).
6930
6931       "privlibexp"
6932           From privlib.U:
6933
6934           This variable is the ~name expanded version of privlib, so that you
6935           may use it directly in Makefiles or shell scripts.
6936
6937       "procselfexe"
6938           From d_procselfexe.U:
6939
6940           If d_procselfexe is defined, $procselfexe is the filename of the
6941           symbolic link pointing to the absolute pathname of the executing
6942           program.
6943
6944       "ptrsize"
6945           From ptrsize.U:
6946
6947           This variable contains the value of the "PTRSIZE" symbol, which
6948           indicates to the C program how many bytes there are in a pointer.
6949
6950   q
6951       "quadkind"
6952           From quadtype.U:
6953
6954           This variable, if defined, encodes the type of a quad: 1 = int, 2 =
6955           long, 3 = long long, 4 = int64_t.
6956
6957       "quadtype"
6958           From quadtype.U:
6959
6960           This variable defines Quad_t to be something like long, int, long
6961           long, int64_t, or whatever type is used for 64-bit integers.
6962
6963   r
6964       "randbits"
6965           From randfunc.U:
6966
6967           Indicates how many bits are produced by the function used to
6968           generate normalized random numbers.
6969
6970       "randfunc"
6971           From randfunc.U:
6972
6973           Indicates the name of the random number function to use.  Values
6974           include drand48, random, and rand. In C programs, the "Drand01"
6975           macro is defined to generate uniformly distributed random numbers
6976           over the range [0., 1.[ (see drand01 and nrand).
6977
6978       "random_r_proto"
6979           From d_random_r.U:
6980
6981           This variable encodes the prototype of random_r.  It is zero if
6982           d_random_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
6983           of reentr.h if d_random_r is defined.
6984
6985       "randseedtype"
6986           From randfunc.U:
6987
6988           Indicates the type of the argument of the seedfunc.
6989
6990       "ranlib"
6991           From orderlib.U:
6992
6993           This variable is set to the pathname of the ranlib program, if it
6994           is needed to generate random libraries.  Set to ":" if ar can
6995           generate random libraries or if random libraries are not supported
6996
6997       "rd_nodata"
6998           From nblock_io.U:
6999
7000           This variable holds the return code from read() when no data is
7001           present. It should be -1, but some systems return 0 when "O_NDELAY"
7002           is used, which is a shame because you cannot make the difference
7003           between no data and an EOF.. Sigh!
7004
7005       "readdir64_r_proto"
7006           From d_readdir64_r.U:
7007
7008           This variable encodes the prototype of readdir64_r.  It is zero if
7009           d_readdir64_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
7010           macros of reentr.h if d_readdir64_r is defined.
7011
7012       "readdir_r_proto"
7013           From d_readdir_r.U:
7014
7015           This variable encodes the prototype of readdir_r.  It is zero if
7016           d_readdir_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
7017           of reentr.h if d_readdir_r is defined.
7018
7019       "revision"
7020           From patchlevel.U:
7021
7022           The value of revision comes from the patchlevel.h file.  In a
7023           version number such as 5.6.1, this is the 5.  In patchlevel.h, this
7024           is referred to as "PERL_REVISION".
7025
7026       "rm"
7027           From Loc.U:
7028
7029           This variable is used internally by Configure to determine the full
7030           pathname (if any) of the rm program.  After Configure runs, the
7031           value is reset to a plain "rm" and is not useful.
7032
7033       "rm_try"
7034           From Unix.U:
7035
7036           This is a cleanup variable for try test programs.  Internal
7037           Configure use only.
7038
7039       "rmail"
7040           From Loc.U:
7041
7042           This variable is defined but not used by Configure.  The value is
7043           the empty string and is not useful.
7044
7045       "run"
7046           From Cross.U:
7047
7048           This variable contains the command used by Configure to copy and
7049           execute a cross-compiled executable in the target host.  Useful and
7050           available only during Perl build.  Empty string '' if not cross-
7051           compiling.
7052
7053       "runnm"
7054           From usenm.U:
7055
7056           This variable contains "true" or "false" depending whether the nm
7057           extraction should be performed or not, according to the value of
7058           usenm and the flags on the Configure command line.
7059
7060   s
7061       "sched_yield"
7062           From d_pthread_y.U:
7063
7064           This variable defines the way to yield the execution of the current
7065           thread.
7066
7067       "scriptdir"
7068           From scriptdir.U:
7069
7070           This variable holds the name of the directory in which the user
7071           wants to put publicly scripts for the package in question.  It is
7072           either the same directory as for binaries, or a special one that
7073           can be mounted across different architectures, like /usr/share.
7074           Programs must be prepared to deal with ~name expansion.
7075
7076       "scriptdirexp"
7077           From scriptdir.U:
7078
7079           This variable is the same as scriptdir, but is filename expanded at
7080           configuration time, for programs not wanting to bother with it.
7081
7082       "sed"
7083           From Loc.U:
7084
7085           This variable is used internally by Configure to determine the full
7086           pathname (if any) of the sed program.  After Configure runs, the
7087           value is reset to a plain "sed" and is not useful.
7088
7089       "seedfunc"
7090           From randfunc.U:
7091
7092           Indicates the random number generating seed function.  Values
7093           include srand48, srandom, and srand.
7094
7095       "selectminbits"
7096           From selectminbits.U:
7097
7098           This variable holds the minimum number of bits operated by select.
7099           That is, if you do select(n, ...), how many bits at least will be
7100           cleared in the masks if some activity is detected.  Usually this is
7101           either n or 32*ceil(n/32), especially many little-endians do the
7102           latter.  This is only useful if you have select(), naturally.
7103
7104       "selecttype"
7105           From selecttype.U:
7106
7107           This variable holds the type used for the 2nd, 3rd, and 4th
7108           arguments to select.  Usually, this is "fd_set *", if "HAS_FD_SET"
7109           is defined, and "int *" otherwise.  This is only useful if you have
7110           select(), naturally.
7111
7112       "sendmail"
7113           From Loc.U:
7114
7115           This variable is defined but not used by Configure.  The value is
7116           the empty string and is not useful.
7117
7118       "setgrent_r_proto"
7119           From d_setgrent_r.U:
7120
7121           This variable encodes the prototype of setgrent_r.  It is zero if
7122           d_setgrent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
7123           macros of reentr.h if d_setgrent_r is defined.
7124
7125       "sethostent_r_proto"
7126           From d_sethostent_r.U:
7127
7128           This variable encodes the prototype of sethostent_r.  It is zero if
7129           d_sethostent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
7130           macros of reentr.h if d_sethostent_r is defined.
7131
7132       "setlocale_r_proto"
7133           From d_setlocale_r.U:
7134
7135           This variable encodes the prototype of setlocale_r.  It is zero if
7136           d_setlocale_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
7137           macros of reentr.h if d_setlocale_r is defined.
7138
7139       "setnetent_r_proto"
7140           From d_setnetent_r.U:
7141
7142           This variable encodes the prototype of setnetent_r.  It is zero if
7143           d_setnetent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
7144           macros of reentr.h if d_setnetent_r is defined.
7145
7146       "setprotoent_r_proto"
7147           From d_setprotoent_r.U:
7148
7149           This variable encodes the prototype of setprotoent_r.  It is zero
7150           if d_setprotoent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
7151           macros of reentr.h if d_setprotoent_r is defined.
7152
7153       "setpwent_r_proto"
7154           From d_setpwent_r.U:
7155
7156           This variable encodes the prototype of setpwent_r.  It is zero if
7157           d_setpwent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
7158           macros of reentr.h if d_setpwent_r is defined.
7159
7160       "setservent_r_proto"
7161           From d_setservent_r.U:
7162
7163           This variable encodes the prototype of setservent_r.  It is zero if
7164           d_setservent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
7165           macros of reentr.h if d_setservent_r is defined.
7166
7167       "sGMTIME_max"
7168           From time_size.U:
7169
7170           This variable defines the maximum value of the time_t offset that
7171           the system function gmtime () accepts
7172
7173       "sGMTIME_min"
7174           From time_size.U:
7175
7176           This variable defines the minimum value of the time_t offset that
7177           the system function gmtime () accepts
7178
7179       "sh"
7180           From sh.U:
7181
7182           This variable contains the full pathname of the shell used on this
7183           system to execute Bourne shell scripts.  Usually, this will be
7184           /bin/sh, though it's possible that some systems will have /bin/ksh,
7185           /bin/pdksh, /bin/ash, /bin/bash, or even something such as
7186           D:/bin/sh.exe.  This unit comes before Options.U, so you can't set
7187           sh with a "-D" option, though you can override this (and startsh)
7188           with "-O -Dsh=/bin/whatever -Dstartsh=whatever"
7189
7190       "shar"
7191           From Loc.U:
7192
7193           This variable is defined but not used by Configure.  The value is
7194           the empty string and is not useful.
7195
7196       "sharpbang"
7197           From spitshell.U:
7198
7199           This variable contains the string #! if this system supports that
7200           construct.
7201
7202       "shmattype"
7203           From d_shmat.U:
7204
7205           This symbol contains the type of pointer returned by shmat().  It
7206           can be "void *" or "char *".
7207
7208       "shortsize"
7209           From intsize.U:
7210
7211           This variable contains the value of the "SHORTSIZE" symbol which
7212           indicates to the C program how many bytes there are in a short.
7213
7214       "shrpenv"
7215           From libperl.U:
7216
7217           If the user builds a shared libperl.so, then we need to tell the
7218           "perl" executable where it will be able to find the installed
7219           libperl.so.  One way to do this on some systems is to set the
7220           environment variable "LD_RUN_PATH" to the directory that will be
7221           the final location of the shared libperl.so.  The makefile can use
7222           this with something like $shrpenv $("CC") -o perl perlmain.o
7223           $libperl $libs Typical values are shrpenv="env
7224           "LD_RUN_PATH"=$archlibexp/"CORE"" or shrpenv='' See the main perl
7225           Makefile.SH for actual working usage.
7226
7227           Alternatively, we might be able to use a command line option such
7228           as -R $archlibexp/"CORE" (Solaris) or -Wl,-rpath $archlibexp/"CORE"
7229           (Linux).
7230
7231       "shsharp"
7232           From spitshell.U:
7233
7234           This variable tells further Configure units whether your sh can
7235           handle # comments.
7236
7237       "sig_count"
7238           From sig_name.U:
7239
7240           This variable holds a number larger than the largest valid signal
7241           number.  This is usually the same as the "NSIG" macro.
7242
7243       "sig_name"
7244           From sig_name.U:
7245
7246           This variable holds the signal names, space separated. The leading
7247           "SIG" in signal name is removed.  A "ZERO" is prepended to the
7248           list.  This is currently not used, sig_name_init is used instead.
7249
7250       "sig_name_init"
7251           From sig_name.U:
7252
7253           This variable holds the signal names, enclosed in double quotes and
7254           separated by commas, suitable for use in the "SIG_NAME" definition
7255           below.  A "ZERO" is prepended to the list, and the list is
7256           terminated with a plain 0.  The leading "SIG" in signal names is
7257           removed. See sig_num.
7258
7259       "sig_num"
7260           From sig_name.U:
7261
7262           This variable holds the signal numbers, space separated. A "ZERO"
7263           is prepended to the list (corresponding to the fake "SIGZERO").
7264           Those numbers correspond to  the value of the signal listed in the
7265           same place within the sig_name list.  This is currently not used,
7266           sig_num_init is used instead.
7267
7268       "sig_num_init"
7269           From sig_name.U:
7270
7271           This variable holds the signal numbers, enclosed in double quotes
7272           and separated by commas, suitable for use in the "SIG_NUM"
7273           definition below.  A "ZERO" is prepended to the list, and the list
7274           is terminated with a plain 0.
7275
7276       "sig_size"
7277           From sig_name.U:
7278
7279           This variable contains the number of elements of the sig_name and
7280           sig_num arrays.
7281
7282       "signal_t"
7283           From d_voidsig.U:
7284
7285           This variable holds the type of the signal handler (void or int).
7286
7287       "sitearch"
7288           From sitearch.U:
7289
7290           This variable contains the eventual value of the "SITEARCH" symbol,
7291           which is the name of the private library for this package.  It may
7292           have a ~ on the front. It is up to the makefile to eventually
7293           create this directory while performing installation (with ~
7294           substitution).  The standard distribution will put nothing in this
7295           directory.  After perl has been installed, users may install their
7296           own local architecture-dependent modules in this directory with
7297           MakeMaker Makefile.PL or equivalent.  See "INSTALL" for details.
7298
7299       "sitearchexp"
7300           From sitearch.U:
7301
7302           This variable is the ~name expanded version of sitearch, so that
7303           you may use it directly in Makefiles or shell scripts.
7304
7305       "sitebin"
7306           From sitebin.U:
7307
7308           This variable holds the name of the directory in which the user
7309           wants to put add-on publicly executable files for the package in
7310           question.  It is most often a local directory such as
7311           /usr/local/bin. Programs using this variable must be prepared to
7312           deal with ~name substitution.  The standard distribution will put
7313           nothing in this directory.  After perl has been installed, users
7314           may install their own local executables in this directory with
7315           MakeMaker Makefile.PL or equivalent.  See "INSTALL" for details.
7316
7317       "sitebinexp"
7318           From sitebin.U:
7319
7320           This is the same as the sitebin variable, but is filename expanded
7321           at configuration time, for use in your makefiles.
7322
7323       "sitehtml1dir"
7324           From sitehtml1dir.U:
7325
7326           This variable contains the name of the directory in which site-
7327           specific html source pages are to be put.  It is the responsibility
7328           of the Makefile.SH to get the value of this into the proper
7329           command.  You must be prepared to do the ~name expansion yourself.
7330           The standard distribution will put nothing in this directory.
7331           After perl has been installed, users may install their own local
7332           html pages in this directory with MakeMaker Makefile.PL or
7333           equivalent.  See "INSTALL" for details.
7334
7335       "sitehtml1direxp"
7336           From sitehtml1dir.U:
7337
7338           This variable is the same as the sitehtml1dir variable, but is
7339           filename expanded at configuration time, for convenient use in
7340           makefiles.
7341
7342       "sitehtml3dir"
7343           From sitehtml3dir.U:
7344
7345           This variable contains the name of the directory in which site-
7346           specific library html source pages are to be put.  It is the
7347           responsibility of the Makefile.SH to get the value of this into the
7348           proper command.  You must be prepared to do the ~name expansion
7349           yourself.  The standard distribution will put nothing in this
7350           directory.  After perl has been installed, users may install their
7351           own local library html pages in this directory with MakeMaker
7352           Makefile.PL or equivalent.  See "INSTALL" for details.
7353
7354       "sitehtml3direxp"
7355           From sitehtml3dir.U:
7356
7357           This variable is the same as the sitehtml3dir variable, but is
7358           filename expanded at configuration time, for convenient use in
7359           makefiles.
7360
7361       "sitelib"
7362           From sitelib.U:
7363
7364           This variable contains the eventual value of the "SITELIB" symbol,
7365           which is the name of the private library for this package.  It may
7366           have a ~ on the front. It is up to the makefile to eventually
7367           create this directory while performing installation (with ~
7368           substitution).  The standard distribution will put nothing in this
7369           directory.  After perl has been installed, users may install their
7370           own local architecture-independent modules in this directory with
7371           MakeMaker Makefile.PL or equivalent.  See "INSTALL" for details.
7372
7373       "sitelib_stem"
7374           From sitelib.U:
7375
7376           This variable is $sitelibexp with any trailing version-specific
7377           component removed.  The elements in inc_version_list
7378           (inc_version_list.U) can be tacked onto this variable to generate a
7379           list of directories to search.
7380
7381       "sitelibexp"
7382           From sitelib.U:
7383
7384           This variable is the ~name expanded version of sitelib, so that you
7385           may use it directly in Makefiles or shell scripts.
7386
7387       "siteman1dir"
7388           From siteman1dir.U:
7389
7390           This variable contains the name of the directory in which site-
7391           specific manual source pages are to be put.  It is the
7392           responsibility of the Makefile.SH to get the value of this into the
7393           proper command.  You must be prepared to do the ~name expansion
7394           yourself.  The standard distribution will put nothing in this
7395           directory.  After perl has been installed, users may install their
7396           own local man1 pages in this directory with MakeMaker Makefile.PL
7397           or equivalent.  See "INSTALL" for details.
7398
7399       "siteman1direxp"
7400           From siteman1dir.U:
7401
7402           This variable is the same as the siteman1dir variable, but is
7403           filename expanded at configuration time, for convenient use in
7404           makefiles.
7405
7406       "siteman3dir"
7407           From siteman3dir.U:
7408
7409           This variable contains the name of the directory in which site-
7410           specific library man source pages are to be put.  It is the
7411           responsibility of the Makefile.SH to get the value of this into the
7412           proper command.  You must be prepared to do the ~name expansion
7413           yourself.  The standard distribution will put nothing in this
7414           directory.  After perl has been installed, users may install their
7415           own local man3 pages in this directory with MakeMaker Makefile.PL
7416           or equivalent.  See "INSTALL" for details.
7417
7418       "siteman3direxp"
7419           From siteman3dir.U:
7420
7421           This variable is the same as the siteman3dir variable, but is
7422           filename expanded at configuration time, for convenient use in
7423           makefiles.
7424
7425       "siteprefix"
7426           From siteprefix.U:
7427
7428           This variable holds the full absolute path of the directory below
7429           which the user will install add-on packages.  See "INSTALL" for
7430           usage and examples.
7431
7432       "siteprefixexp"
7433           From siteprefix.U:
7434
7435           This variable holds the full absolute path of the directory below
7436           which the user will install add-on packages.  Derived from
7437           siteprefix.
7438
7439       "sitescript"
7440           From sitescript.U:
7441
7442           This variable holds the name of the directory in which the user
7443           wants to put add-on publicly executable files for the package in
7444           question.  It is most often a local directory such as
7445           /usr/local/bin. Programs using this variable must be prepared to
7446           deal with ~name substitution.  The standard distribution will put
7447           nothing in this directory.  After perl has been installed, users
7448           may install their own local scripts in this directory with
7449           MakeMaker Makefile.PL or equivalent.  See "INSTALL" for details.
7450
7451       "sitescriptexp"
7452           From sitescript.U:
7453
7454           This is the same as the sitescript variable, but is filename
7455           expanded at configuration time, for use in your makefiles.
7456
7457       "sizesize"
7458           From sizesize.U:
7459
7460           This variable contains the size of a sizetype in bytes.
7461
7462       "sizetype"
7463           From sizetype.U:
7464
7465           This variable defines sizetype to be something like size_t,
7466           unsigned long, or whatever type is used to declare length
7467           parameters for string functions.
7468
7469       "sleep"
7470           From Loc.U:
7471
7472           This variable is defined but not used by Configure.  The value is
7473           the empty string and is not useful.
7474
7475       "sLOCALTIME_max"
7476           From time_size.U:
7477
7478           This variable defines the maximum value of the time_t offset that
7479           the system function localtime () accepts
7480
7481       "sLOCALTIME_min"
7482           From time_size.U:
7483
7484           This variable defines the minimum value of the time_t offset that
7485           the system function localtime () accepts
7486
7487       "smail"
7488           From Loc.U:
7489
7490           This variable is defined but not used by Configure.  The value is
7491           the empty string and is not useful.
7492
7493       "so"
7494           From so.U:
7495
7496           This variable holds the extension used to identify shared libraries
7497           (also known as shared objects) on the system. Usually set to "so".
7498
7499       "sockethdr"
7500           From d_socket.U:
7501
7502           This variable has any cpp "-I" flags needed for socket support.
7503
7504       "socketlib"
7505           From d_socket.U:
7506
7507           This variable has the names of any libraries needed for socket
7508           support.
7509
7510       "socksizetype"
7511           From socksizetype.U:
7512
7513           This variable holds the type used for the size argument for various
7514           socket calls like accept.  Usual values include socklen_t, size_t,
7515           and int.
7516
7517       "sort"
7518           From Loc.U:
7519
7520           This variable is used internally by Configure to determine the full
7521           pathname (if any) of the sort program.  After Configure runs, the
7522           value is reset to a plain "sort" and is not useful.
7523
7524       "spackage"
7525           From package.U:
7526
7527           This variable contains the name of the package being constructed,
7528           with the first letter uppercased, i.e. suitable for starting
7529           sentences.
7530
7531       "spitshell"
7532           From spitshell.U:
7533
7534           This variable contains the command necessary to spit out a runnable
7535           shell on this system.  It is either cat or a grep "-v" for #
7536           comments.
7537
7538       "sPRId64"
7539           From quadfio.U:
7540
7541           This variable, if defined, contains the string used by stdio to
7542           format 64-bit decimal numbers (format "d") for output.
7543
7544       "sPRIeldbl"
7545           From longdblfio.U:
7546
7547           This variable, if defined, contains the string used by stdio to
7548           format long doubles (format "e") for output.
7549
7550       "sPRIEUldbl"
7551           From longdblfio.U:
7552
7553           This variable, if defined, contains the string used by stdio to
7554           format long doubles (format "E") for output.  The "U" in the name
7555           is to separate this from sPRIeldbl so that even case-blind systems
7556           can see the difference.
7557
7558       "sPRIfldbl"
7559           From longdblfio.U:
7560
7561           This variable, if defined, contains the string used by stdio to
7562           format long doubles (format "f") for output.
7563
7564       "sPRIFUldbl"
7565           From longdblfio.U:
7566
7567           This variable, if defined, contains the string used by stdio to
7568           format long doubles (format "F") for output.  The "U" in the name
7569           is to separate this from sPRIfldbl so that even case-blind systems
7570           can see the difference.
7571
7572       "sPRIgldbl"
7573           From longdblfio.U:
7574
7575           This variable, if defined, contains the string used by stdio to
7576           format long doubles (format "g") for output.
7577
7578       "sPRIGUldbl"
7579           From longdblfio.U:
7580
7581           This variable, if defined, contains the string used by stdio to
7582           format long doubles (format "G") for output.  The "U" in the name
7583           is to separate this from sPRIgldbl so that even case-blind systems
7584           can see the difference.
7585
7586       "sPRIi64"
7587           From quadfio.U:
7588
7589           This variable, if defined, contains the string used by stdio to
7590           format 64-bit decimal numbers (format "i") for output.
7591
7592       "sPRIo64"
7593           From quadfio.U:
7594
7595           This variable, if defined, contains the string used by stdio to
7596           format 64-bit octal numbers (format "o") for output.
7597
7598       "sPRIu64"
7599           From quadfio.U:
7600
7601           This variable, if defined, contains the string used by stdio to
7602           format 64-bit unsigned decimal numbers (format "u") for output.
7603
7604       "sPRIx64"
7605           From quadfio.U:
7606
7607           This variable, if defined, contains the string used by stdio to
7608           format 64-bit hexadecimal numbers (format "x") for output.
7609
7610       "sPRIXU64"
7611           From quadfio.U:
7612
7613           This variable, if defined, contains the string used by stdio to
7614           format 64-bit hExADECimAl numbers (format "X") for output.  The "U"
7615           in the name is to separate this from sPRIx64 so that even case-
7616           blind systems can see the difference.
7617
7618       "srand48_r_proto"
7619           From d_srand48_r.U:
7620
7621           This variable encodes the prototype of srand48_r.  It is zero if
7622           d_srand48_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
7623           of reentr.h if d_srand48_r is defined.
7624
7625       "srandom_r_proto"
7626           From d_srandom_r.U:
7627
7628           This variable encodes the prototype of srandom_r.  It is zero if
7629           d_srandom_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
7630           of reentr.h if d_srandom_r is defined.
7631
7632       "src"
7633           From src.U:
7634
7635           This variable holds the (possibly relative) path of the package
7636           source.  It is up to the Makefile to use this variable and set
7637           "VPATH" accordingly to find the sources remotely.  Use $pkgsrc to
7638           have an absolute path.
7639
7640       "sSCNfldbl"
7641           From longdblfio.U:
7642
7643           This variable, if defined, contains the string used by stdio to
7644           format long doubles (format "f") for input.
7645
7646       "ssizetype"
7647           From ssizetype.U:
7648
7649           This variable defines ssizetype to be something like ssize_t, long
7650           or int.  It is used by functions that return a count of bytes or an
7651           error condition.  It must be a signed type.  We will pick a type
7652           such that sizeof(SSize_t) == sizeof(Size_t).
7653
7654       "st_dev_sign"
7655           From st_dev_def.U:
7656
7657           This variable contains the signedness of struct stat's st_dev.  1
7658           for unsigned, -1 for signed.
7659
7660       "st_dev_size"
7661           From st_dev_def.U:
7662
7663           This variable contains the size of struct stat's st_dev in bytes.
7664
7665       "st_ino_sign"
7666           From st_ino_def.U:
7667
7668           This variable contains the signedness of struct stat's st_ino.  1
7669           for unsigned, -1 for signed.
7670
7671       "st_ino_size"
7672           From st_ino_def.U:
7673
7674           This variable contains the size of struct stat's st_ino in bytes.
7675
7676       "startperl"
7677           From startperl.U:
7678
7679           This variable contains the string to put on the front of a perl
7680           script to make sure (hopefully) that it runs with perl and not some
7681           shell. Of course, that leading line must be followed by the
7682           classical perl idiom: eval 'exec perl -S $0 ${1+$@}' if
7683           $running_under_some_shell; to guarantee perl startup should the
7684           shell execute the script. Note that this magic incantation is not
7685           understood by csh.
7686
7687       "startsh"
7688           From startsh.U:
7689
7690           This variable contains the string to put on the front of a shell
7691           script to make sure (hopefully) that it runs with sh and not some
7692           other shell.
7693
7694       "static_ext"
7695           From Extensions.U:
7696
7697           This variable holds a list of "XS" extension files we want to link
7698           statically into the package.  It is used by Makefile.
7699
7700       "stdchar"
7701           From stdchar.U:
7702
7703           This variable conditionally defines "STDCHAR" to be the type of
7704           char used in stdio.h.  It has the values "unsigned char" or "char".
7705
7706       "stdio_base"
7707           From d_stdstdio.U:
7708
7709           This variable defines how, given a "FILE" pointer, fp, to access
7710           the _base field (or equivalent) of stdio.h's "FILE" structure.
7711           This will be used to define the macro FILE_base(fp).
7712
7713       "stdio_bufsiz"
7714           From d_stdstdio.U:
7715
7716           This variable defines how, given a "FILE" pointer, fp, to determine
7717           the number of bytes store in the I/O buffer pointer to by the _base
7718           field (or equivalent) of stdio.h's "FILE" structure.  This will be
7719           used to define the macro FILE_bufsiz(fp).
7720
7721       "stdio_cnt"
7722           From d_stdstdio.U:
7723
7724           This variable defines how, given a "FILE" pointer, fp, to access
7725           the _cnt field (or equivalent) of stdio.h's "FILE" structure.  This
7726           will be used to define the macro FILE_cnt(fp).
7727
7728       "stdio_filbuf"
7729           From d_stdstdio.U:
7730
7731           This variable defines how, given a "FILE" pointer, fp, to tell
7732           stdio to refill its internal buffers (?).  This will be used to
7733           define the macro FILE_filbuf(fp).
7734
7735       "stdio_ptr"
7736           From d_stdstdio.U:
7737
7738           This variable defines how, given a "FILE" pointer, fp, to access
7739           the _ptr field (or equivalent) of stdio.h's "FILE" structure.  This
7740           will be used to define the macro FILE_ptr(fp).
7741
7742       "stdio_stream_array"
7743           From stdio_streams.U:
7744
7745           This variable tells the name of the array holding the stdio
7746           streams.  Usual values include _iob, __iob, and __sF.
7747
7748       "strerror_r_proto"
7749           From d_strerror_r.U:
7750
7751           This variable encodes the prototype of strerror_r.  It is zero if
7752           d_strerror_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
7753           macros of reentr.h if d_strerror_r is defined.
7754
7755       "submit"
7756           From Loc.U:
7757
7758           This variable is defined but not used by Configure.  The value is
7759           the empty string and is not useful.
7760
7761       "subversion"
7762           From patchlevel.U:
7763
7764           The subversion level of this package.  The value of subversion
7765           comes from the patchlevel.h file.  In a version number such as
7766           5.6.1, this is the 1.  In patchlevel.h, this is referred to as
7767           "PERL_SUBVERSION".  This is unique to perl.
7768
7769       "sysman"
7770           From sysman.U:
7771
7772           This variable holds the place where the manual is located on this
7773           system. It is not the place where the user wants to put his manual
7774           pages. Rather it is the place where Configure may look to find
7775           manual for unix commands (section 1 of the manual usually). See
7776           mansrc.
7777
7778       "sysroot"
7779           From Sysroot.U:
7780
7781           This variable is empty unless supplied by the Configure user.  It
7782           can contain a path to an alternative root directory, under which
7783           headers and libraries for the compilation target can be found. This
7784           is generally used when cross-compiling using a gcc-like compiler.
7785
7786   t
7787       "tail"
7788           From Loc.U:
7789
7790           This variable is defined but not used by Configure.  The value is
7791           the empty string and is not useful.
7792
7793       "tar"
7794           From Loc.U:
7795
7796           This variable is defined but not used by Configure.  The value is
7797           the empty string and is not useful.
7798
7799       "targetarch"
7800           From Cross.U:
7801
7802           If cross-compiling, this variable contains the target architecture.
7803           If not, this will be empty.
7804
7805       "targetdir"
7806           From Cross.U:
7807
7808           This variable contains a path that will be created on the target
7809           host using targetmkdir, and then used to copy the cross-compiled
7810           executables to. Defaults to /tmp if not set.
7811
7812       "targetenv"
7813           From Cross.U:
7814
7815           If cross-compiling, this variable can be used to modify the
7816           environment on the target system.  However, how and where it's
7817           used, and even if it's used at all, is entirely dependent on both
7818           the transport mechanism (targetrun) and what the target system is.
7819           Unless the relevant documentation says otherwise, it is genereally
7820           not useful.
7821
7822       "targethost"
7823           From Cross.U:
7824
7825           This variable contains the name of a separate host machine that can
7826           be used to run compiled test programs and perl tests on.  Set to
7827           empty string if not in use.
7828
7829       "targetmkdir"
7830           From Cross.U:
7831
7832           This variable contains the command used by Configure to create a
7833           new directory on the target host.
7834
7835       "targetport"
7836           From Cross.U:
7837
7838           This variable contains the number of a network port to be used to
7839           connect to the host in targethost, if unset defaults to 22 for ssh.
7840
7841       "targetsh"
7842           From sh.U:
7843
7844           If cross-compiling, this variable contains the location of sh on
7845           the target system.  If not, this will be the same as $sh.
7846
7847       "tbl"
7848           From Loc.U:
7849
7850           This variable is defined but not used by Configure.  The value is
7851           the empty string and is not useful.
7852
7853       "tee"
7854           From Loc.U:
7855
7856           This variable is defined but not used by Configure.  The value is
7857           the empty string and is not useful.
7858
7859       "test"
7860           From Loc.U:
7861
7862           This variable is used internally by Configure to determine the full
7863           pathname (if any) of the test program.  After Configure runs, the
7864           value is reset to a plain "test" and is not useful.
7865
7866       "timeincl"
7867           From i_time.U:
7868
7869           This variable holds the full path of the included time header(s).
7870
7871       "timetype"
7872           From d_time.U:
7873
7874           This variable holds the type returned by time(). It can be long, or
7875           time_t on "BSD" sites (in which case <sys/types.h> should be
7876           included). Anyway, the type Time_t should be used.
7877
7878       "tmpnam_r_proto"
7879           From d_tmpnam_r.U:
7880
7881           This variable encodes the prototype of tmpnam_r.  It is zero if
7882           d_tmpnam_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
7883           of reentr.h if d_tmpnam_r is defined.
7884
7885       "to"
7886           From Cross.U:
7887
7888           This variable contains the command used by Configure to copy to
7889           from the target host.  Useful and available only during Perl build.
7890           The string ":" if not cross-compiling.
7891
7892       "touch"
7893           From Loc.U:
7894
7895           This variable is used internally by Configure to determine the full
7896           pathname (if any) of the touch program.  After Configure runs, the
7897           value is reset to a plain "touch" and is not useful.
7898
7899       "tr"
7900           From Loc.U:
7901
7902           This variable is used internally by Configure to determine the full
7903           pathname (if any) of the tr program.  After Configure runs, the
7904           value is reset to a plain "tr" and is not useful.
7905
7906       "trnl"
7907           From trnl.U:
7908
7909           This variable contains the value to be passed to the tr(1) command
7910           to transliterate a newline.  Typical values are "\012" and "\n".
7911           This is needed for "EBCDIC" systems where newline is not
7912           necessarily "\012".
7913
7914       "troff"
7915           From Loc.U:
7916
7917           This variable is defined but not used by Configure.  The value is
7918           the empty string and is not useful.
7919
7920       "ttyname_r_proto"
7921           From d_ttyname_r.U:
7922
7923           This variable encodes the prototype of ttyname_r.  It is zero if
7924           d_ttyname_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
7925           of reentr.h if d_ttyname_r is defined.
7926
7927   u
7928       "u16size"
7929           From perlxv.U:
7930
7931           This variable is the size of an U16 in bytes.
7932
7933       "u16type"
7934           From perlxv.U:
7935
7936           This variable contains the C type used for Perl's U16.
7937
7938       "u32size"
7939           From perlxv.U:
7940
7941           This variable is the size of an U32 in bytes.
7942
7943       "u32type"
7944           From perlxv.U:
7945
7946           This variable contains the C type used for Perl's U32.
7947
7948       "u64size"
7949           From perlxv.U:
7950
7951           This variable is the size of an U64 in bytes.
7952
7953       "u64type"
7954           From perlxv.U:
7955
7956           This variable contains the C type used for Perl's U64.
7957
7958       "u8size"
7959           From perlxv.U:
7960
7961           This variable is the size of an U8 in bytes.
7962
7963       "u8type"
7964           From perlxv.U:
7965
7966           This variable contains the C type used for Perl's U8.
7967
7968       "uidformat"
7969           From uidf.U:
7970
7971           This variable contains the format string used for printing a Uid_t.
7972
7973       "uidsign"
7974           From uidsign.U:
7975
7976           This variable contains the signedness of a uidtype.  1 for
7977           unsigned, -1 for signed.
7978
7979       "uidsize"
7980           From uidsize.U:
7981
7982           This variable contains the size of a uidtype in bytes.
7983
7984       "uidtype"
7985           From uidtype.U:
7986
7987           This variable defines Uid_t to be something like uid_t, int,
7988           ushort, or whatever type is used to declare user ids in the kernel.
7989
7990       "uname"
7991           From Loc.U:
7992
7993           This variable is used internally by Configure to determine the full
7994           pathname (if any) of the uname program.  After Configure runs, the
7995           value is reset to a plain "uname" and is not useful.
7996
7997       "uniq"
7998           From Loc.U:
7999
8000           This variable is used internally by Configure to determine the full
8001           pathname (if any) of the uniq program.  After Configure runs, the
8002           value is reset to a plain "uniq" and is not useful.
8003
8004       "uquadtype"
8005           From quadtype.U:
8006
8007           This variable defines Uquad_t to be something like unsigned long,
8008           unsigned int, unsigned long long, uint64_t, or whatever type is
8009           used for 64-bit integers.
8010
8011       "use64bitall"
8012           From use64bits.U:
8013
8014           This variable conditionally defines the USE_64_BIT_ALL symbol, and
8015           indicates that 64-bit integer types should be used when available.
8016           The maximal possible 64-bitness is employed: LP64 or ILP64, meaning
8017           that you will be able to use more than 2 gigabytes of memory.  This
8018           mode is even more binary incompatible than USE_64_BIT_INT. You may
8019           not be able to run the resulting executable in a 32-bit "CPU" at
8020           all or you may need at least to reboot your "OS" to 64-bit mode.
8021
8022       "use64bitint"
8023           From use64bits.U:
8024
8025           This variable conditionally defines the USE_64_BIT_INT symbol, and
8026           indicates that 64-bit integer types should be used when available.
8027           The minimal possible 64-bitness is employed, just enough to get
8028           64-bit integers into Perl.  This may mean using for example "long
8029           longs", while your memory may still be limited to 2 gigabytes.
8030
8031       "usecbacktrace"
8032           From usebacktrace.U:
8033
8034           This variable indicates whether we are compiling with backtrace
8035           support.
8036
8037       "usecrosscompile"
8038           From Cross.U:
8039
8040           This variable conditionally defines the "USE_CROSS_COMPILE" symbol,
8041           and indicates that Perl has been cross-compiled.
8042
8043       "usedefaultstrict"
8044           From usedefaultstrict.U:
8045
8046           This setting provides a mechanism for perl developers to enable
8047           strict by default. These defaults do not apply when perl is run via
8048           -e or -E.
8049
8050       "usedevel"
8051           From Devel.U:
8052
8053           This variable indicates that Perl was configured with development
8054           features enabled.  This should not be done for production builds.
8055
8056       "usedl"
8057           From dlsrc.U:
8058
8059           This variable indicates if the system supports dynamic loading of
8060           some sort.  See also dlsrc and dlobj.
8061
8062       "usedtrace"
8063           From usedtrace.U:
8064
8065           This variable indicates whether we are compiling with dtrace
8066           support. See also dtrace.
8067
8068       "usefaststdio"
8069           From usefaststdio.U:
8070
8071           This variable conditionally defines the "USE_FAST_STDIO" symbol,
8072           and indicates that Perl should be built to use "fast stdio".
8073           Defaults to define in Perls 5.8 and earlier, to undef later.
8074
8075       "useithreads"
8076           From usethreads.U:
8077
8078           This variable conditionally defines the "USE_ITHREADS" symbol, and
8079           indicates that Perl should be built to use the interpreter-based
8080           threading implementation.
8081
8082       "usekernprocpathname"
8083           From usekernprocpathname.U:
8084
8085           This variable, indicates that we can use sysctl with
8086           "KERN_PROC_PATHNAME" to get a full path for the executable, and
8087           hence convert $^X to an absolute path.
8088
8089       "uselanginfo"
8090           From Extensions.U:
8091
8092           This variable holds either "true" or "false" to indicate whether
8093           the I18N::Langinfo extension should be used.  The sole use for this
8094           currently is to allow an easy mechanism for users to skip this
8095           extension from the Configure command line.
8096
8097       "uselargefiles"
8098           From uselfs.U:
8099
8100           This variable conditionally defines the "USE_LARGE_FILES" symbol,
8101           and indicates that large file interfaces should be used when
8102           available.
8103
8104       "uselongdouble"
8105           From uselongdbl.U:
8106
8107           This variable conditionally defines the "USE_LONG_DOUBLE" symbol,
8108           and indicates that long doubles should be used when available.
8109
8110       "usemallocwrap"
8111           From mallocsrc.U:
8112
8113           This variable contains y if we are wrapping malloc to prevent
8114           integer overflow during size calculations.
8115
8116       "usemorebits"
8117           From usemorebits.U:
8118
8119           This variable conditionally defines the "USE_MORE_BITS" symbol, and
8120           indicates that explicit 64-bit interfaces and long doubles should
8121           be used when available.
8122
8123       "usemultiplicity"
8124           From usemultiplicity.U:
8125
8126           This variable conditionally defines the "MULTIPLICITY" symbol, and
8127           indicates that Perl should be built to use multiplicity.
8128
8129       "usemymalloc"
8130           From mallocsrc.U:
8131
8132           This variable contains y if the malloc that comes with this package
8133           is desired over the system's version of malloc.  People often
8134           include special versions of malloc for efficiency, but such
8135           versions are often less portable.  See also mallocsrc and
8136           mallocobj.  If this is "y", then -lmalloc is removed from $libs.
8137
8138       "usenm"
8139           From usenm.U:
8140
8141           This variable contains "true" or "false" depending whether the nm
8142           extraction is wanted or not.
8143
8144       "usensgetexecutablepath"
8145           From usensgetexecutablepath.U:
8146
8147           This symbol, if defined, indicates that we can use
8148           _NSGetExecutablePath and realpath to get a full path for the
8149           executable, and hence convert $^X to an absolute path.
8150
8151       "useopcode"
8152           From Extensions.U:
8153
8154           This variable holds either "true" or "false" to indicate whether
8155           the Opcode extension should be used.  The sole use for this
8156           currently is to allow an easy mechanism for users to skip the
8157           Opcode extension from the Configure command line.
8158
8159       "useperlio"
8160           From useperlio.U:
8161
8162           This variable conditionally defines the "USE_PERLIO" symbol, and
8163           indicates that the PerlIO abstraction should be used throughout.
8164
8165       "useposix"
8166           From Extensions.U:
8167
8168           This variable holds either "true" or "false" to indicate whether
8169           the "POSIX" extension should be used.  The sole use for this
8170           currently is to allow an easy mechanism for hints files to indicate
8171           that "POSIX" will not compile on a particular system.
8172
8173       "usequadmath"
8174           From usequadmath.U:
8175
8176           This variable conditionally defines the "USE_QUADMATH" symbol, and
8177           indicates that the quadmath library __float128 long doubles should
8178           be used when available.
8179
8180       "usereentrant"
8181           From usethreads.U:
8182
8183           This variable conditionally defines the "USE_REENTRANT_API" symbol,
8184           which indicates that the thread code may try to use the various _r
8185           versions of library functions.  This is only potentially meaningful
8186           if usethreads is set and is very experimental, it is not even
8187           prompted for.
8188
8189       "userelocatableinc"
8190           From bin.U:
8191
8192           This variable is set to true to indicate that perl should relocate
8193           @"INC" entries at runtime based on the path to the perl binary.
8194           Any @"INC" paths starting .../ are relocated relative to the
8195           directory containing the perl binary, and a logical cleanup of the
8196           path is then made around the join point (removing dir/../ pairs)
8197
8198       "useshrplib"
8199           From libperl.U:
8200
8201           This variable is set to "true" if the user wishes to build a shared
8202           libperl, and "false" otherwise.
8203
8204       "usesitecustomize"
8205           From d_sitecustomize.U:
8206
8207           This variable is set to true when the user requires a mechanism
8208           that allows the sysadmin to add entries to @"INC" at runtime.  This
8209           variable being set, makes perl run $sitelib/sitecustomize.pl at
8210           startup.
8211
8212       "usesocks"
8213           From usesocks.U:
8214
8215           This variable conditionally defines the "USE_SOCKS" symbol, and
8216           indicates that Perl should be built to use "SOCKS".
8217
8218       "usethreads"
8219           From usethreads.U:
8220
8221           This variable conditionally defines the "USE_THREADS" symbol, and
8222           indicates that Perl should be built to use threads.
8223
8224       "usevendorprefix"
8225           From vendorprefix.U:
8226
8227           This variable tells whether the vendorprefix and consequently other
8228           vendor* paths are in use.
8229
8230       "useversionedarchname"
8231           From archname.U:
8232
8233           This variable indicates whether to include the $api_versionstring
8234           as a component of the $archname.
8235
8236       "usevfork"
8237           From d_vfork.U:
8238
8239           This variable is set to true when the user accepts to use vfork.
8240           It is set to false when no vfork is available or when the user
8241           explicitly requests not to use vfork.
8242
8243       "usrinc"
8244           From usrinc.U:
8245
8246           This variable holds the path of the include files, which is usually
8247           /usr/include. It is mainly used by other Configure units.
8248
8249       "uuname"
8250           From Loc.U:
8251
8252           This variable is defined but not used by Configure.  The value is
8253           the empty string and is not useful.
8254
8255       "uvoformat"
8256           From perlxvf.U:
8257
8258           This variable contains the format string used for printing a Perl
8259           "UV" as an unsigned octal integer.
8260
8261       "uvsize"
8262           From perlxv.U:
8263
8264           This variable is the size of a "UV" in bytes.
8265
8266       "uvtype"
8267           From perlxv.U:
8268
8269           This variable contains the C type used for Perl's "UV".
8270
8271       "uvuformat"
8272           From perlxvf.U:
8273
8274           This variable contains the format string used for printing a Perl
8275           "UV" as an unsigned decimal integer.
8276
8277       "uvxformat"
8278           From perlxvf.U:
8279
8280           This variable contains the format string used for printing a Perl
8281           "UV" as an unsigned hexadecimal integer in lowercase abcdef.
8282
8283       "uvXUformat"
8284           From perlxvf.U:
8285
8286           This variable contains the format string used for printing a Perl
8287           "UV" as an unsigned hexadecimal integer in uppercase "ABCDEF".
8288
8289   v
8290       "vendorarch"
8291           From vendorarch.U:
8292
8293           This variable contains the value of the "PERL_VENDORARCH" symbol.
8294           It may have a ~ on the front.  The standard distribution will put
8295           nothing in this directory.  Vendors who distribute perl may wish to
8296           place their own architecture-dependent modules and extensions in
8297           this directory with MakeMaker Makefile.PL "INSTALLDIRS"=vendor or
8298           equivalent.  See "INSTALL" for details.
8299
8300       "vendorarchexp"
8301           From vendorarch.U:
8302
8303           This variable is the ~name expanded version of vendorarch, so that
8304           you may use it directly in Makefiles or shell scripts.
8305
8306       "vendorbin"
8307           From vendorbin.U:
8308
8309           This variable contains the eventual value of the "VENDORBIN"
8310           symbol.  It may have a ~ on the front.  The standard distribution
8311           will put nothing in this directory.  Vendors who distribute perl
8312           may wish to place additional binaries in this directory with
8313           MakeMaker Makefile.PL "INSTALLDIRS"=vendor or equivalent.  See
8314           "INSTALL" for details.
8315
8316       "vendorbinexp"
8317           From vendorbin.U:
8318
8319           This variable is the ~name expanded version of vendorbin, so that
8320           you may use it directly in Makefiles or shell scripts.
8321
8322       "vendorhtml1dir"
8323           From vendorhtml1dir.U:
8324
8325           This variable contains the name of the directory for html pages.
8326           It may have a ~ on the front.  The standard distribution will put
8327           nothing in this directory.  Vendors who distribute perl may wish to
8328           place their own html pages in this directory with MakeMaker
8329           Makefile.PL "INSTALLDIRS"=vendor or equivalent.  See "INSTALL" for
8330           details.
8331
8332       "vendorhtml1direxp"
8333           From vendorhtml1dir.U:
8334
8335           This variable is the ~name expanded version of vendorhtml1dir, so
8336           that you may use it directly in Makefiles or shell scripts.
8337
8338       "vendorhtml3dir"
8339           From vendorhtml3dir.U:
8340
8341           This variable contains the name of the directory for html library
8342           pages.  It may have a ~ on the front.  The standard distribution
8343           will put nothing in this directory.  Vendors who distribute perl
8344           may wish to place their own html pages for modules and extensions
8345           in this directory with MakeMaker Makefile.PL "INSTALLDIRS"=vendor
8346           or equivalent.  See "INSTALL" for details.
8347
8348       "vendorhtml3direxp"
8349           From vendorhtml3dir.U:
8350
8351           This variable is the ~name expanded version of vendorhtml3dir, so
8352           that you may use it directly in Makefiles or shell scripts.
8353
8354       "vendorlib"
8355           From vendorlib.U:
8356
8357           This variable contains the eventual value of the "VENDORLIB"
8358           symbol, which is the name of the private library for this package.
8359           The standard distribution will put nothing in this directory.
8360           Vendors who distribute perl may wish to place their own modules in
8361           this directory with MakeMaker Makefile.PL "INSTALLDIRS"=vendor or
8362           equivalent.  See "INSTALL" for details.
8363
8364       "vendorlib_stem"
8365           From vendorlib.U:
8366
8367           This variable is $vendorlibexp with any trailing version-specific
8368           component removed.  The elements in inc_version_list
8369           (inc_version_list.U) can be tacked onto this variable to generate a
8370           list of directories to search.
8371
8372       "vendorlibexp"
8373           From vendorlib.U:
8374
8375           This variable is the ~name expanded version of vendorlib, so that
8376           you may use it directly in Makefiles or shell scripts.
8377
8378       "vendorman1dir"
8379           From vendorman1dir.U:
8380
8381           This variable contains the name of the directory for man1 pages.
8382           It may have a ~ on the front.  The standard distribution will put
8383           nothing in this directory.  Vendors who distribute perl may wish to
8384           place their own man1 pages in this directory with MakeMaker
8385           Makefile.PL "INSTALLDIRS"=vendor or equivalent.  See "INSTALL" for
8386           details.
8387
8388       "vendorman1direxp"
8389           From vendorman1dir.U:
8390
8391           This variable is the ~name expanded version of vendorman1dir, so
8392           that you may use it directly in Makefiles or shell scripts.
8393
8394       "vendorman3dir"
8395           From vendorman3dir.U:
8396
8397           This variable contains the name of the directory for man3 pages.
8398           It may have a ~ on the front.  The standard distribution will put
8399           nothing in this directory.  Vendors who distribute perl may wish to
8400           place their own man3 pages in this directory with MakeMaker
8401           Makefile.PL "INSTALLDIRS"=vendor or equivalent.  See "INSTALL" for
8402           details.
8403
8404       "vendorman3direxp"
8405           From vendorman3dir.U:
8406
8407           This variable is the ~name expanded version of vendorman3dir, so
8408           that you may use it directly in Makefiles or shell scripts.
8409
8410       "vendorprefix"
8411           From vendorprefix.U:
8412
8413           This variable holds the full absolute path of the directory below
8414           which the vendor will install add-on packages.  See "INSTALL" for
8415           usage and examples.
8416
8417       "vendorprefixexp"
8418           From vendorprefix.U:
8419
8420           This variable holds the full absolute path of the directory below
8421           which the vendor will install add-on packages.  Derived from
8422           vendorprefix.
8423
8424       "vendorscript"
8425           From vendorscript.U:
8426
8427           This variable contains the eventual value of the "VENDORSCRIPT"
8428           symbol.  It may have a ~ on the front.  The standard distribution
8429           will put nothing in this directory.  Vendors who distribute perl
8430           may wish to place additional executable scripts in this directory
8431           with MakeMaker Makefile.PL "INSTALLDIRS"=vendor or equivalent.  See
8432           "INSTALL" for details.
8433
8434       "vendorscriptexp"
8435           From vendorscript.U:
8436
8437           This variable is the ~name expanded version of vendorscript, so
8438           that you may use it directly in Makefiles or shell scripts.
8439
8440       "version"
8441           From patchlevel.U:
8442
8443           The full version number of this package, such as 5.6.1 (or 5_6_1).
8444           This combines revision, patchlevel, and subversion to get the full
8445           version number, including any possible subversions.  This is
8446           suitable for use as a directory name, and hence is filesystem
8447           dependent.
8448
8449       "version_patchlevel_string"
8450           From patchlevel.U:
8451
8452           This is a string combining version, subversion and perl_patchlevel
8453           (if perl_patchlevel is non-zero).  It is typically something like
8454           'version 7 subversion 1'  or 'version 7 subversion 1 patchlevel
8455           11224' It is computed here to avoid duplication of code in
8456           myconfig.SH and lib/Config.pm.
8457
8458       "versiononly"
8459           From versiononly.U:
8460
8461           If set, this symbol indicates that only the version-specific
8462           components of a perl installation should be installed.  This may be
8463           useful for making a test installation of a new version without
8464           disturbing the existing installation.  Setting versiononly is
8465           equivalent to setting installperl's -v option.  In particular, the
8466           non-versioned scripts and programs such as a2p, c2ph, h2xs, pod2*,
8467           and perldoc are not installed (see "INSTALL" for a more complete
8468           list).  Nor are the man pages installed.  Usually, this is undef.
8469
8470       "vi"
8471           From Loc.U:
8472
8473           This variable is defined but not used by Configure.  The value is
8474           the empty string and is not useful.
8475
8476   x
8477       "xlibpth"
8478           From libpth.U:
8479
8480           This variable holds extra path (space-separated) used to find
8481           libraries on this platform, for example "CPU"-specific libraries
8482           (on multi-"CPU" platforms) may be listed here.
8483
8484       "xlocale_needed"
8485           From d_newlocale.U:
8486
8487           This symbol, if defined, indicates that the C program should
8488           include <xlocale.h> to get newlocale() and its friends.
8489
8490   y
8491       "yacc"
8492           From yacc.U:
8493
8494           This variable holds the name of the compiler compiler we want to
8495           use in the Makefile. It can be yacc, byacc, or bison -y.
8496
8497       "yaccflags"
8498           From yacc.U:
8499
8500           This variable contains any additional yacc flags desired by the
8501           user.  It is up to the Makefile to use this.
8502
8503   z
8504       "zcat"
8505           From Loc.U:
8506
8507           This variable is defined but not used by Configure.  The value is
8508           the empty string and is not useful.
8509
8510       "zip"
8511           From Loc.U:
8512
8513           This variable is used internally by Configure to determine the full
8514           pathname (if any) of the zip program.  After Configure runs, the
8515           value is reset to a plain "zip" and is not useful.
8516

GIT DATA

8518       Information on the git commit from which the current perl binary was
8519       compiled can be found in the variable $Config::Git_Data.  The variable
8520       is a structured string that looks something like this:
8521
8522         git_commit_id='ea0c2dbd5f5ac6845ecc7ec6696415bf8e27bd52'
8523         git_describe='GitLive-blead-1076-gea0c2db'
8524         git_branch='smartmatch'
8525         git_uncommitted_changes=''
8526         git_commit_id_title='Commit id:'
8527         git_commit_date='2009-05-09 17:47:31 +0200'
8528
8529       Its format is not guaranteed not to change over time.
8530

NOTE

8532       This module contains a good example of how to use tie to implement a
8533       cache and an example of how to make a tied variable readonly to those
8534       outside of it.
8535
8536
8537
8538perl v5.36.3                      2023-11-30                       Config(3pm)
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