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

GIT DATA

8453       Information on the git commit from which the current perl binary was
8454       compiled can be found in the variable $Config::Git_Data.  The variable
8455       is a structured string that looks something like this:
8456
8457         git_commit_id='ea0c2dbd5f5ac6845ecc7ec6696415bf8e27bd52'
8458         git_describe='GitLive-blead-1076-gea0c2db'
8459         git_branch='smartmatch'
8460         git_uncommitted_changes=''
8461         git_commit_id_title='Commit id:'
8462         git_commit_date='2009-05-09 17:47:31 +0200'
8463
8464       Its format is not guaranteed not to change over time.
8465

NOTE

8467       This module contains a good example of how to use tie to implement a
8468       cache and an example of how to make a tied variable readonly to those
8469       outside of it.
8470
8471
8472
8473perl v5.34.0                      2021-10-18                       Config(3pm)
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