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       http://perl5.git.perl.org/perl.git/blob/HEAD:/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       "ansi2knr"
181           From ansi2knr.U:
182
183           This variable is set if the user needs to run ansi2knr.  Currently,
184           this is not supported, so we just abort.
185
186       "aphostname"
187           From d_gethname.U:
188
189           This variable contains the command which can be used to compute the
190           host name. The command is fully qualified by its absolute path, to
191           make it safe when used by a process with super-user privileges.
192
193       "api_revision"
194           From patchlevel.U:
195
196           The three variables, api_revision, api_version, and api_subversion,
197           specify the version of the oldest perl binary compatible with the
198           present perl.  In a full version string such as 5.6.1, api_revision
199           is the 5.  Prior to 5.5.640, the format was a floating point
200           number, like 5.00563.
201
202           perl.c:incpush() and lib/lib.pm will automatically search in
203           $sitelib/.. for older directories back to the limit specified by
204           these api_ variables.  This is only useful if you have a perl
205           library directory tree structured like the default one.  See
206           "INSTALL" for how this works.  The versioned site_perl directory
207           was introduced in 5.005, so that is the lowest possible value.  The
208           version list appropriate for the current system is determined in
209           inc_version_list.U.
210
211           "XXX" To do:  Since compatibility can depend on compile time
212           options (such as bincompat, longlong, etc.) it should (perhaps) be
213           set by Configure, but currently it isn't.  Currently, we read a
214           hard-wired value from patchlevel.h.  Perhaps what we ought to do is
215           take the hard-wired value from patchlevel.h but then modify it if
216           the current Configure options warrant.  patchlevel.h then would use
217           an #ifdef guard.
218
219       "api_subversion"
220           From patchlevel.U:
221
222           The three variables, api_revision, api_version, and api_subversion,
223           specify the version of the oldest perl binary compatible with the
224           present perl.  In a full version string such as 5.6.1,
225           api_subversion is the 1.  See api_revision for full details.
226
227       "api_version"
228           From patchlevel.U:
229
230           The three variables, api_revision, api_version, and api_subversion,
231           specify the version of the oldest perl binary compatible with the
232           present perl.  In a full version string such as 5.6.1, api_version
233           is the 6.  See api_revision for full details.  As a special case,
234           5.5.0 is rendered in the old-style as 5.005.  (In the 5.005_0x
235           maintenance series, this was the only versioned directory in
236           $sitelib.)
237
238       "api_versionstring"
239           From patchlevel.U:
240
241           This variable combines api_revision, api_version, and
242           api_subversion in a format such as 5.6.1 (or 5_6_1) suitable for
243           use as a directory name.  This is filesystem dependent.
244
245       "ar"
246           From Loc.U:
247
248           This variable is used internally by Configure to determine the full
249           pathname (if any) of the ar program.  After Configure runs, the
250           value is reset to a plain "ar" and is not useful.
251
252       "archlib"
253           From archlib.U:
254
255           This variable holds the name of the directory in which the user
256           wants to put architecture-dependent public library files for
257           $package.  It is most often a local directory such as
258           /usr/local/lib.  Programs using this variable must be prepared to
259           deal with filename expansion.
260
261       "archlibexp"
262           From archlib.U:
263
264           This variable is the same as the archlib variable, but is filename
265           expanded at configuration time, for convenient use.
266
267       "archname"
268           From archname.U:
269
270           This variable is a short name to characterize the current
271           architecture.  It is used mainly to construct the default archlib.
272
273       "archname64"
274           From use64bits.U:
275
276           This variable is used for the 64-bitness part of $archname.
277
278       "archobjs"
279           From Unix.U:
280
281           This variable defines any additional objects that must be linked in
282           with the program on this architecture.  On unix, it is usually
283           empty.  It is typically used to include emulations of unix calls or
284           other facilities.  For perl on OS/2, for example, this would
285           include os2/os2.obj.
286
287       "asctime_r_proto"
288           From d_asctime_r.U:
289
290           This variable encodes the prototype of asctime_r.  It is zero if
291           d_asctime_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
292           of reentr.h if d_asctime_r is defined.
293
294       "awk"
295           From Loc.U:
296
297           This variable is used internally by Configure to determine the full
298           pathname (if any) of the awk program.  After Configure runs, the
299           value is reset to a plain "awk" and is not useful.
300
301   b
302       "baserev"
303           From baserev.U:
304
305           The base revision level of this package, from the .package file.
306
307       "bash"
308           From Loc.U:
309
310           This variable is defined but not used by Configure.  The value is
311           the empty string and is not useful.
312
313       "bin"
314           From bin.U:
315
316           This variable holds the name of the directory in which the user
317           wants to put publicly executable images for the package in
318           question.  It is most often a local directory such as
319           /usr/local/bin. Programs using this variable must be prepared to
320           deal with ~name substitution.
321
322       "bin_ELF"
323           From dlsrc.U:
324
325           This variable saves the result from configure if generated binaries
326           are in "ELF" format. Only set to defined when the test has actually
327           been performed, and the result was positive.
328
329       "binexp"
330           From bin.U:
331
332           This is the same as the bin variable, but is filename expanded at
333           configuration time, for use in your makefiles.
334
335       "bison"
336           From Loc.U:
337
338           This variable is used internally by Configure to determine the full
339           pathname (if any) of the bison program.  After Configure runs, the
340           value is reset to a plain "bison" and is not useful.
341
342       "byacc"
343           From Loc.U:
344
345           This variable is used internally by Configure to determine the full
346           pathname (if any) of the byacc program.  After Configure runs, the
347           value is reset to a plain "byacc" and is not useful.
348
349       "byteorder"
350           From byteorder.U:
351
352           This variable holds the byte order in a "UV". In the following,
353           larger digits indicate more significance.  The variable byteorder
354           is either 4321 on a big-endian machine, or 1234 on a little-endian,
355           or 87654321 on a Cray ... or 3412 with weird order !
356
357   c
358       "c" From n.U:
359
360           This variable contains the \c string if that is what causes the
361           echo command to suppress newline.  Otherwise it is null.  Correct
362           usage is $echo $n "prompt for a question: $c".
363
364       "castflags"
365           From d_castneg.U:
366
367           This variable contains a flag that precise difficulties the
368           compiler has casting odd floating values to unsigned long: 0 = ok 1
369           = couldn't cast < 0 2 = couldn't cast >= 0x80000000 4 = couldn't
370           cast in argument expression list
371
372       "cat"
373           From Loc.U:
374
375           This variable is used internally by Configure to determine the full
376           pathname (if any) of the cat program.  After Configure runs, the
377           value is reset to a plain "cat" and is not useful.
378
379       "cc"
380           From cc.U:
381
382           This variable holds the name of a command to execute a C compiler
383           which can resolve multiple global references that happen to have
384           the same name.  Usual values are "cc" and "gcc".  Fervent "ANSI"
385           compilers may be called "c89".  "AIX" has xlc.
386
387       "cccdlflags"
388           From dlsrc.U:
389
390           This variable contains any special flags that might need to be
391           passed with "cc -c" to compile modules to be used to create a
392           shared library that will be used for dynamic loading.  For hpux,
393           this should be +z.  It is up to the makefile to use it.
394
395       "ccdlflags"
396           From dlsrc.U:
397
398           This variable contains any special flags that might need to be
399           passed to cc to link with a shared library for dynamic loading.  It
400           is up to the makefile to use it.  For sunos 4.1, it should be
401           empty.
402
403       "ccflags"
404           From ccflags.U:
405
406           This variable contains any additional C compiler flags desired by
407           the user.  It is up to the Makefile to use this.
408
409       "ccflags_uselargefiles"
410           From uselfs.U:
411
412           This variable contains the compiler flags needed by large file
413           builds and added to ccflags by hints files.
414
415       "ccname"
416           From Checkcc.U:
417
418           This can set either by hints files or by Configure.  If using gcc,
419           this is gcc, and if not, usually equal to cc, unimpressive, no?
420           Some platforms, however, make good use of this by storing the
421           flavor of the C compiler being used here.  For example if using the
422           Sun WorkShop suite, ccname will be "workshop".
423
424       "ccsymbols"
425           From Cppsym.U:
426
427           The variable contains the symbols defined by the C compiler alone.
428           The symbols defined by cpp or by cc when it calls cpp are not in
429           this list, see cppsymbols and cppccsymbols.  The list is a space-
430           separated list of symbol=value tokens.
431
432       "ccversion"
433           From Checkcc.U:
434
435           This can set either by hints files or by Configure.  If using a
436           (non-gcc) vendor cc, this variable may contain a version for the
437           compiler.
438
439       "cf_by"
440           From cf_who.U:
441
442           Login name of the person who ran the Configure script and answered
443           the questions. This is used to tag both config.sh and config_h.SH.
444
445       "cf_email"
446           From cf_email.U:
447
448           Electronic mail address of the person who ran Configure. This can
449           be used by units that require the user's e-mail, like MailList.U.
450
451       "cf_time"
452           From cf_who.U:
453
454           Holds the output of the "date" command when the configuration file
455           was produced. This is used to tag both config.sh and config_h.SH.
456
457       "charbits"
458           From charsize.U:
459
460           This variable contains the value of the "CHARBITS" symbol, which
461           indicates to the C program how many bits there are in a character.
462
463       "charsize"
464           From charsize.U:
465
466           This variable contains the value of the "CHARSIZE" symbol, which
467           indicates to the C program how many bytes there are in a character.
468
469       "chgrp"
470           From Loc.U:
471
472           This variable is defined but not used by Configure.  The value is
473           the empty string and is not useful.
474
475       "chmod"
476           From Loc.U:
477
478           This variable is used internally by Configure to determine the full
479           pathname (if any) of the chmod program.  After Configure runs, the
480           value is reset to a plain "chmod" and is not useful.
481
482       "chown"
483           From Loc.U:
484
485           This variable is defined but not used by Configure.  The value is
486           the empty string and is not useful.
487
488       "clocktype"
489           From d_times.U:
490
491           This variable holds the type returned by times(). It can be long,
492           or clock_t on "BSD" sites (in which case <sys/types.h> should be
493           included).
494
495       "comm"
496           From Loc.U:
497
498           This variable is used internally by Configure to determine the full
499           pathname (if any) of the comm program.  After Configure runs, the
500           value is reset to a plain "comm" and is not useful.
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_access"
662           From d_access.U:
663
664           This variable conditionally defines "HAS_ACCESS" if the access()
665           system call is available to check for access permissions using real
666           IDs.
667
668       "d_accessx"
669           From d_accessx.U:
670
671           This variable conditionally defines the "HAS_ACCESSX" symbol, which
672           indicates to the C program that the accessx() routine is available.
673
674       "d_acosh"
675           From d_acosh.U:
676
677           This variable conditionally defines the "HAS_ACOSH" symbol, which
678           indicates to the C program that the acosh() routine is available.
679
680       "d_aintl"
681           From d_aintl.U:
682
683           This variable conditionally defines the "HAS_AINTL" symbol, which
684           indicates to the C program that the aintl() routine is available.
685           If copysignl is also present we can emulate modfl.
686
687       "d_alarm"
688           From d_alarm.U:
689
690           This variable conditionally defines the "HAS_ALARM" symbol, which
691           indicates to the C program that the alarm() routine is available.
692
693       "d_archlib"
694           From archlib.U:
695
696           This variable conditionally defines "ARCHLIB" to hold the pathname
697           of architecture-dependent library files for $package.  If $archlib
698           is the same as $privlib, then this is set to undef.
699
700       "d_asctime64"
701           From d_timefuncs64.U:
702
703           This variable conditionally defines the HAS_ASCTIME64 symbol, which
704           indicates to the C program that the asctime64 () routine is
705           available.
706
707       "d_asctime_r"
708           From d_asctime_r.U:
709
710           This variable conditionally defines the "HAS_ASCTIME_R" symbol,
711           which indicates to the C program that the asctime_r() routine is
712           available.
713
714       "d_asinh"
715           From d_asinh.U:
716
717           This variable conditionally defines the "HAS_ASINH" symbol, which
718           indicates to the C program that the asinh() routine is available.
719
720       "d_atanh"
721           From d_atanh.U:
722
723           This variable conditionally defines the "HAS_ATANH" symbol, which
724           indicates to the C program that the atanh() routine is available.
725
726       "d_atolf"
727           From atolf.U:
728
729           This variable conditionally defines the "HAS_ATOLF" symbol, which
730           indicates to the C program that the atolf() routine is available.
731
732       "d_atoll"
733           From atoll.U:
734
735           This variable conditionally defines the "HAS_ATOLL" symbol, which
736           indicates to the C program that the atoll() routine is available.
737
738       "d_attribute_deprecated"
739           From d_attribut.U:
740
741           This variable conditionally defines "HASATTRIBUTE_DEPRECATED",
742           which indicates that "GCC" can handle the attribute for marking
743           deprecated APIs
744
745       "d_attribute_format"
746           From d_attribut.U:
747
748           This variable conditionally defines "HASATTRIBUTE_FORMAT", which
749           indicates the C compiler can check for printf-like formats.
750
751       "d_attribute_malloc"
752           From d_attribut.U:
753
754           This variable conditionally defines "HASATTRIBUTE_MALLOC", which
755           indicates the C compiler can understand functions as having malloc-
756           like semantics.
757
758       "d_attribute_nonnull"
759           From d_attribut.U:
760
761           This variable conditionally defines "HASATTRIBUTE_NONNULL", which
762           indicates that the C compiler can know that certain arguments must
763           not be "NULL", and will check accordingly at compile time.
764
765       "d_attribute_noreturn"
766           From d_attribut.U:
767
768           This variable conditionally defines "HASATTRIBUTE_NORETURN", which
769           indicates that the C compiler can know that certain functions are
770           guaranteed never to return.
771
772       "d_attribute_pure"
773           From d_attribut.U:
774
775           This variable conditionally defines "HASATTRIBUTE_PURE", which
776           indicates that the C compiler can know that certain functions are
777           "pure" functions, meaning that they have no side effects, and only
778           rely on function input and/or global data for their results.
779
780       "d_attribute_unused"
781           From d_attribut.U:
782
783           This variable conditionally defines "HASATTRIBUTE_UNUSED", which
784           indicates that the C compiler can know that certain variables and
785           arguments may not always be used, and to not throw warnings if they
786           don't get used.
787
788       "d_attribute_warn_unused_result"
789           From d_attribut.U:
790
791           This variable conditionally defines
792           "HASATTRIBUTE_WARN_UNUSED_RESULT", which indicates that the C
793           compiler can know that certain functions have a return values that
794           must not be ignored, such as malloc() or open().
795
796       "d_backtrace"
797           From d_backtrace.U:
798
799           This variable conditionally defines the "HAS_BACKTRACE" symbol,
800           which indicates to the C program that the backtrace() routine is
801           available to get a stack trace.
802
803       "d_bcmp"
804           From d_bcmp.U:
805
806           This variable conditionally defines the "HAS_BCMP" symbol if the
807           bcmp() routine is available to compare strings.
808
809       "d_bcopy"
810           From d_bcopy.U:
811
812           This variable conditionally defines the "HAS_BCOPY" symbol if the
813           bcopy() routine is available to copy strings.
814
815       "d_bsd"
816           From Guess.U:
817
818           This symbol conditionally defines the symbol "BSD" when running on
819           a "BSD" system.
820
821       "d_bsdgetpgrp"
822           From d_getpgrp.U:
823
824           This variable conditionally defines "USE_BSD_GETPGRP" if getpgrp
825           needs one arguments whereas "USG" one needs none.
826
827       "d_bsdsetpgrp"
828           From d_setpgrp.U:
829
830           This variable conditionally defines "USE_BSD_SETPGRP" if setpgrp
831           needs two arguments whereas "USG" one needs none.  See also
832           d_setpgid for a "POSIX" interface.
833
834       "d_builtin_choose_expr"
835           From d_builtin.U:
836
837           This conditionally defines "HAS_BUILTIN_CHOOSE_EXPR", which
838           indicates that the compiler supports __builtin_choose_expr(x,y,z).
839           This built-in function is analogous to the "x?y:z" operator in C,
840           except that the expression returned has its type unaltered by
841           promotion rules. Also, the built-in function does not evaluate the
842           expression that was not chosen.
843
844       "d_builtin_expect"
845           From d_builtin.U:
846
847           This conditionally defines "HAS_BUILTIN_EXPECT", which indicates
848           that the compiler supports __builtin_expect(exp,c).  You may use
849           __builtin_expect to provide the compiler with branch prediction
850           information.
851
852       "d_bzero"
853           From d_bzero.U:
854
855           This variable conditionally defines the "HAS_BZERO" symbol if the
856           bzero() routine is available to set memory to 0.
857
858       "d_c99_variadic_macros"
859           From d_c99_variadic.U:
860
861           This variable conditionally defines the HAS_C99_VARIADIC_MACROS
862           symbol, which indicates to the C program that C99 variadic macros
863           are available.
864
865       "d_casti32"
866           From d_casti32.U:
867
868           This variable conditionally defines CASTI32, which indicates
869           whether the C compiler can cast large floats to 32-bit ints.
870
871       "d_castneg"
872           From d_castneg.U:
873
874           This variable conditionally defines "CASTNEG", which indicates
875           whether the C compiler can cast negative float to unsigned.
876
877       "d_cbrt"
878           From d_cbrt.U:
879
880           This variable conditionally defines the "HAS_CBRT" symbol, which
881           indicates to the C program that the cbrt() (cube root) function is
882           available.
883
884       "d_charvspr"
885           From d_vprintf.U:
886
887           This variable conditionally defines "CHARVSPRINTF" if this system
888           has vsprintf returning type (char*).  The trend seems to be to
889           declare it as "int vsprintf()".
890
891       "d_chown"
892           From d_chown.U:
893
894           This variable conditionally defines the "HAS_CHOWN" symbol, which
895           indicates to the C program that the chown() routine is available.
896
897       "d_chroot"
898           From d_chroot.U:
899
900           This variable conditionally defines the "HAS_CHROOT" symbol, which
901           indicates to the C program that the chroot() routine is available.
902
903       "d_chsize"
904           From d_chsize.U:
905
906           This variable conditionally defines the "CHSIZE" symbol, which
907           indicates to the C program that the chsize() routine is available
908           to truncate files.  You might need a -lx to get this routine.
909
910       "d_class"
911           From d_class.U:
912
913           This variable conditionally defines the "HAS_CLASS" symbol, which
914           indicates to the C program that the class() routine is available.
915
916       "d_clearenv"
917           From d_clearenv.U:
918
919           This variable conditionally defines the "HAS_CLEARENV" symbol,
920           which indicates to the C program that the clearenv () routine is
921           available.
922
923       "d_closedir"
924           From d_closedir.U:
925
926           This variable conditionally defines "HAS_CLOSEDIR" if closedir() is
927           available.
928
929       "d_cmsghdr_s"
930           From d_cmsghdr_s.U:
931
932           This variable conditionally defines the "HAS_STRUCT_CMSGHDR"
933           symbol, which indicates that the struct cmsghdr is supported.
934
935       "d_const"
936           From d_const.U:
937
938           This variable conditionally defines the "HASCONST" symbol, which
939           indicates to the C program that this C compiler knows about the
940           const type.
941
942       "d_copysign"
943           From d_copysign.U:
944
945           This variable conditionally defines the "HAS_COPYSIGN" symbol,
946           which indicates to the C program that the copysign() routine is
947           available.
948
949       "d_copysignl"
950           From d_copysignl.U:
951
952           This variable conditionally defines the "HAS_COPYSIGNL" symbol,
953           which indicates to the C program that the copysignl() routine is
954           available.  If aintl is also present we can emulate modfl.
955
956       "d_cplusplus"
957           From d_cplusplus.U:
958
959           This variable conditionally defines the "USE_CPLUSPLUS" symbol,
960           which indicates that a C++ compiler was used to compiled Perl and
961           will be used to compile extensions.
962
963       "d_crypt"
964           From d_crypt.U:
965
966           This variable conditionally defines the "CRYPT" symbol, which
967           indicates to the C program that the crypt() routine is available to
968           encrypt passwords and the like.
969
970       "d_crypt_r"
971           From d_crypt_r.U:
972
973           This variable conditionally defines the "HAS_CRYPT_R" symbol, which
974           indicates to the C program that the crypt_r() routine is available.
975
976       "d_csh"
977           From d_csh.U:
978
979           This variable conditionally defines the "CSH" symbol, which
980           indicates to the C program that the C-shell exists.
981
982       "d_ctermid"
983           From d_ctermid.U:
984
985           This variable conditionally defines "CTERMID" if ctermid() is
986           available to generate filename for terminal.
987
988       "d_ctermid_r"
989           From d_ctermid_r.U:
990
991           This variable conditionally defines the "HAS_CTERMID_R" symbol,
992           which indicates to the C program that the ctermid_r() routine is
993           available.
994
995       "d_ctime64"
996           From d_timefuncs64.U:
997
998           This variable conditionally defines the HAS_CTIME64 symbol, which
999           indicates to the C program that the ctime64 () routine is
1000           available.
1001
1002       "d_ctime_r"
1003           From d_ctime_r.U:
1004
1005           This variable conditionally defines the "HAS_CTIME_R" symbol, which
1006           indicates to the C program that the ctime_r() routine is available.
1007
1008       "d_cuserid"
1009           From d_cuserid.U:
1010
1011           This variable conditionally defines the "HAS_CUSERID" symbol, which
1012           indicates to the C program that the cuserid() routine is available
1013           to get character login names.
1014
1015       "d_dbl_dig"
1016           From d_dbl_dig.U:
1017
1018           This variable conditionally defines d_dbl_dig if this system's
1019           header files provide "DBL_DIG", which is the number of significant
1020           digits in a double precision number.
1021
1022       "d_dbminitproto"
1023           From d_dbminitproto.U:
1024
1025           This variable conditionally defines the "HAS_DBMINIT_PROTO" symbol,
1026           which indicates to the C program that the system provides a
1027           prototype for the dbminit() function.  Otherwise, it is up to the
1028           program to supply one.
1029
1030       "d_difftime"
1031           From d_difftime.U:
1032
1033           This variable conditionally defines the "HAS_DIFFTIME" symbol,
1034           which indicates to the C program that the difftime() routine is
1035           available.
1036
1037       "d_difftime64"
1038           From d_timefuncs64.U:
1039
1040           This variable conditionally defines the HAS_DIFFTIME64 symbol,
1041           which indicates to the C program that the difftime64 () routine is
1042           available.
1043
1044       "d_dir_dd_fd"
1045           From d_dir_dd_fd.U:
1046
1047           This variable conditionally defines the "HAS_DIR_DD_FD" symbol,
1048           which indicates that the "DIR" directory stream type contains a
1049           member variable called dd_fd.
1050
1051       "d_dirfd"
1052           From d_dirfd.U:
1053
1054           This variable conditionally defines the "HAS_DIRFD" constant, which
1055           indicates to the C program that dirfd() is available to return the
1056           file descriptor of a directory stream.
1057
1058       "d_dirnamlen"
1059           From i_dirent.U:
1060
1061           This variable conditionally defines "DIRNAMLEN", which indicates to
1062           the C program that the length of directory entry names is provided
1063           by a d_namelen field.
1064
1065       "d_dladdr"
1066           From d_dladdr.U:
1067
1068           This variable conditionally defines the "HAS_DLADDR" symbol, which
1069           indicates to the C program that the dladdr() routine is available
1070           to get a stack trace.
1071
1072       "d_dlerror"
1073           From d_dlerror.U:
1074
1075           This variable conditionally defines the "HAS_DLERROR" symbol, which
1076           indicates to the C program that the dlerror() routine is available.
1077
1078       "d_dlopen"
1079           From d_dlopen.U:
1080
1081           This variable conditionally defines the "HAS_DLOPEN" symbol, which
1082           indicates to the C program that the dlopen() routine is available.
1083
1084       "d_dlsymun"
1085           From d_dlsymun.U:
1086
1087           This variable conditionally defines "DLSYM_NEEDS_UNDERSCORE", which
1088           indicates that we need to prepend an underscore to the symbol name
1089           before calling dlsym().
1090
1091       "d_double_has_inf"
1092           From infnan.U:
1093
1094           This variable conditionally defines the symbol "DOUBLE_HAS_INF"
1095           which indicates that the double type has an infinity.
1096
1097       "d_double_has_nan"
1098           From infnan.U:
1099
1100           This variable conditionally defines the symbol "DOUBLE_HAS_INF"
1101           which indicates that the double type has a not-a-number.
1102
1103       "d_double_has_negative_zero"
1104           From infnan.U:
1105
1106           This variable conditionally defines the symbol
1107           "DOUBLE_HAS_NEGATIVE_ZERO" which indicates that the double type has
1108           a negative zero.
1109
1110       "d_double_has_subnormals"
1111           From infnan.U:
1112
1113           This variable conditionally defines the symbol
1114           "DOUBLE_HAS_SUBNORMALS" which indicates that the double type has
1115           subnormals (denormals).
1116
1117       "d_double_style_cray"
1118           From longdblfio.U:
1119
1120           This variable conditionally defines the symbol "DOUBLE_STYLE_CRAY"
1121           which indicates that the double is the 64-bit "CRAY" mainframe
1122           format.
1123
1124       "d_double_style_ibm"
1125           From longdblfio.U:
1126
1127           This variable conditionally defines the symbol "DOUBLE_STYLE_IBM",
1128           which indicates that the double is the 64-bit "IBM" mainframe
1129           format.
1130
1131       "d_double_style_ieee"
1132           From longdblfio.U:
1133
1134           This variable conditionally defines the symbol "DOUBLE_STYLE_IEEE",
1135           which indicates that the double is the 64-bit "IEEE" 754.
1136
1137       "d_double_style_vax"
1138           From longdblfio.U:
1139
1140           This variable conditionally defines the symbol "DOUBLE_STYLE_VAX",
1141           which indicates that the double is the 64-bit "VAX" format D or G.
1142
1143       "d_dosuid"
1144           From d_dosuid.U:
1145
1146           This variable conditionally defines the symbol "DOSUID", which
1147           tells the C program that it should insert setuid emulation code on
1148           hosts which have setuid #! scripts disabled.
1149
1150       "d_drand48_r"
1151           From d_drand48_r.U:
1152
1153           This variable conditionally defines the HAS_DRAND48_R symbol, which
1154           indicates to the C program that the drand48_r() routine is
1155           available.
1156
1157       "d_drand48proto"
1158           From d_drand48proto.U:
1159
1160           This variable conditionally defines the HAS_DRAND48_PROTO symbol,
1161           which indicates to the C program that the system provides a
1162           prototype for the drand48() function.  Otherwise, it is up to the
1163           program to supply one.
1164
1165       "d_dup2"
1166           From d_dup2.U:
1167
1168           This variable conditionally defines HAS_DUP2 if dup2() is available
1169           to duplicate file descriptors.
1170
1171       "d_duplocale"
1172           From d_newlocale.U:
1173
1174           This variable conditionally defines the "HAS_DUPLOCALE" symbol,
1175           which indicates to the C program that the duplocale() routine is
1176           available to duplicate a locale object.
1177
1178       "d_eaccess"
1179           From d_eaccess.U:
1180
1181           This variable conditionally defines the "HAS_EACCESS" symbol, which
1182           indicates to the C program that the eaccess() routine is available.
1183
1184       "d_endgrent"
1185           From d_endgrent.U:
1186
1187           This variable conditionally defines the "HAS_ENDGRENT" symbol,
1188           which indicates to the C program that the endgrent() routine is
1189           available for sequential access of the group database.
1190
1191       "d_endgrent_r"
1192           From d_endgrent_r.U:
1193
1194           This variable conditionally defines the "HAS_ENDGRENT_R" symbol,
1195           which indicates to the C program that the endgrent_r() routine is
1196           available.
1197
1198       "d_endhent"
1199           From d_endhent.U:
1200
1201           This variable conditionally defines "HAS_ENDHOSTENT" if
1202           endhostent() is available to close whatever was being used for host
1203           queries.
1204
1205       "d_endhostent_r"
1206           From d_endhostent_r.U:
1207
1208           This variable conditionally defines the "HAS_ENDHOSTENT_R" symbol,
1209           which indicates to the C program that the endhostent_r() routine is
1210           available.
1211
1212       "d_endnent"
1213           From d_endnent.U:
1214
1215           This variable conditionally defines "HAS_ENDNETENT" if endnetent()
1216           is available to close whatever was being used for network queries.
1217
1218       "d_endnetent_r"
1219           From d_endnetent_r.U:
1220
1221           This variable conditionally defines the "HAS_ENDNETENT_R" symbol,
1222           which indicates to the C program that the endnetent_r() routine is
1223           available.
1224
1225       "d_endpent"
1226           From d_endpent.U:
1227
1228           This variable conditionally defines "HAS_ENDPROTOENT" if
1229           endprotoent() is available to close whatever was being used for
1230           protocol queries.
1231
1232       "d_endprotoent_r"
1233           From d_endprotoent_r.U:
1234
1235           This variable conditionally defines the "HAS_ENDPROTOENT_R" symbol,
1236           which indicates to the C program that the endprotoent_r() routine
1237           is available.
1238
1239       "d_endpwent"
1240           From d_endpwent.U:
1241
1242           This variable conditionally defines the "HAS_ENDPWENT" symbol,
1243           which indicates to the C program that the endpwent() routine is
1244           available for sequential access of the passwd database.
1245
1246       "d_endpwent_r"
1247           From d_endpwent_r.U:
1248
1249           This variable conditionally defines the "HAS_ENDPWENT_R" symbol,
1250           which indicates to the C program that the endpwent_r() routine is
1251           available.
1252
1253       "d_endsent"
1254           From d_endsent.U:
1255
1256           This variable conditionally defines "HAS_ENDSERVENT" if
1257           endservent() is available to close whatever was being used for
1258           service queries.
1259
1260       "d_endservent_r"
1261           From d_endservent_r.U:
1262
1263           This variable conditionally defines the "HAS_ENDSERVENT_R" symbol,
1264           which indicates to the C program that the endservent_r() routine is
1265           available.
1266
1267       "d_eofnblk"
1268           From nblock_io.U:
1269
1270           This variable conditionally defines "EOF_NONBLOCK" if "EOF" can be
1271           seen when reading from a non-blocking I/O source.
1272
1273       "d_erf"
1274           From d_erf.U:
1275
1276           This variable conditionally defines the "HAS_ERF" symbol, which
1277           indicates to the C program that the erf() routine is available.
1278
1279       "d_erfc"
1280           From d_erfc.U:
1281
1282           This variable conditionally defines the "HAS_ERFC" symbol, which
1283           indicates to the C program that the erfc() routine is available.
1284
1285       "d_eunice"
1286           From Guess.U:
1287
1288           This variable conditionally defines the symbols "EUNICE" and "VAX",
1289           which alerts the C program that it must deal with idiosyncrasies of
1290           "VMS".
1291
1292       "d_exp2"
1293           From d_exp2.U:
1294
1295           This variable conditionally defines the HAS_EXP2 symbol, which
1296           indicates to the C program that the exp2() routine is available.
1297
1298       "d_expm1"
1299           From d_expm1.U:
1300
1301           This variable conditionally defines the HAS_EXPM1 symbol, which
1302           indicates to the C program that the expm1() routine is available.
1303
1304       "d_faststdio"
1305           From d_faststdio.U:
1306
1307           This variable conditionally defines the "HAS_FAST_STDIO" symbol,
1308           which indicates to the C program that the "fast stdio" is available
1309           to manipulate the stdio buffers directly.
1310
1311       "d_fchdir"
1312           From d_fchdir.U:
1313
1314           This variable conditionally defines the "HAS_FCHDIR" symbol, which
1315           indicates to the C program that the fchdir() routine is available.
1316
1317       "d_fchmod"
1318           From d_fchmod.U:
1319
1320           This variable conditionally defines the "HAS_FCHMOD" symbol, which
1321           indicates to the C program that the fchmod() routine is available
1322           to change mode of opened files.
1323
1324       "d_fchown"
1325           From d_fchown.U:
1326
1327           This variable conditionally defines the "HAS_FCHOWN" symbol, which
1328           indicates to the C program that the fchown() routine is available
1329           to change ownership of opened files.
1330
1331       "d_fcntl"
1332           From d_fcntl.U:
1333
1334           This variable conditionally defines the "HAS_FCNTL" symbol, and
1335           indicates whether the fcntl() function exists
1336
1337       "d_fcntl_can_lock"
1338           From d_fcntl_can_lock.U:
1339
1340           This variable conditionally defines the "FCNTL_CAN_LOCK" symbol and
1341           indicates whether file locking with fcntl() works.
1342
1343       "d_fd_macros"
1344           From d_fd_set.U:
1345
1346           This variable contains the eventual value of the "HAS_FD_MACROS"
1347           symbol, which indicates if your C compiler knows about the macros
1348           which manipulate an fd_set.
1349
1350       "d_fd_set"
1351           From d_fd_set.U:
1352
1353           This variable contains the eventual value of the "HAS_FD_SET"
1354           symbol, which indicates if your C compiler knows about the fd_set
1355           typedef.
1356
1357       "d_fdclose"
1358           From d_fdclose.U:
1359
1360           This variable conditionally defines the "HAS_FDCLOSE" symbol, which
1361           indicates to the C program that the fdclose() routine is available.
1362
1363       "d_fdim"
1364           From d_fdim.U:
1365
1366           This variable conditionally defines the "HAS_FDIM" symbol, which
1367           indicates to the C program that the fdim() routine is available.
1368
1369       "d_fds_bits"
1370           From d_fd_set.U:
1371
1372           This variable contains the eventual value of the "HAS_FDS_BITS"
1373           symbol, which indicates if your fd_set typedef contains the
1374           fds_bits member.  If you have an fd_set typedef, but the dweebs who
1375           installed it did a half-fast job and neglected to provide the
1376           macros to manipulate an fd_set, "HAS_FDS_BITS" will let us know how
1377           to fix the gaffe.
1378
1379       "d_fegetround"
1380           From d_fegetround.U:
1381
1382           This variable conditionally defines "HAS_FEGETROUND" if
1383           fegetround() is available to get the floating point rounding mode.
1384
1385       "d_fgetpos"
1386           From d_fgetpos.U:
1387
1388           This variable conditionally defines "HAS_FGETPOS" if fgetpos() is
1389           available to get the file position indicator.
1390
1391       "d_finite"
1392           From d_finite.U:
1393
1394           This variable conditionally defines the "HAS_FINITE" symbol, which
1395           indicates to the C program that the finite() routine is available.
1396
1397       "d_finitel"
1398           From d_finitel.U:
1399
1400           This variable conditionally defines the "HAS_FINITEL" symbol, which
1401           indicates to the C program that the finitel() routine is available.
1402
1403       "d_flexfnam"
1404           From d_flexfnam.U:
1405
1406           This variable conditionally defines the "FLEXFILENAMES" symbol,
1407           which indicates that the system supports filenames longer than 14
1408           characters.
1409
1410       "d_flock"
1411           From d_flock.U:
1412
1413           This variable conditionally defines "HAS_FLOCK" if flock() is
1414           available to do file locking.
1415
1416       "d_flockproto"
1417           From d_flockproto.U:
1418
1419           This variable conditionally defines the "HAS_FLOCK_PROTO" symbol,
1420           which indicates to the C program that the system provides a
1421           prototype for the flock() function.  Otherwise, it is up to the
1422           program to supply one.
1423
1424       "d_fma"
1425           From d_fma.U:
1426
1427           This variable conditionally defines the "HAS_FMA" symbol, which
1428           indicates to the C program that the fma() routine is available.
1429
1430       "d_fmax"
1431           From d_fmax.U:
1432
1433           This variable conditionally defines the "HAS_FMAX" symbol, which
1434           indicates to the C program that the fmax() routine is available.
1435
1436       "d_fmin"
1437           From d_fmin.U:
1438
1439           This variable conditionally defines the "HAS_FMIN" symbol, which
1440           indicates to the C program that the fmin() routine is available.
1441
1442       "d_fork"
1443           From d_fork.U:
1444
1445           This variable conditionally defines the "HAS_FORK" symbol, which
1446           indicates to the C program that the fork() routine is available.
1447
1448       "d_fp_class"
1449           From d_fp_class.U:
1450
1451           This variable conditionally defines the "HAS_FP_CLASS" symbol,
1452           which indicates to the C program that the fp_class() routine is
1453           available.
1454
1455       "d_fp_classify"
1456           From d_fpclassify.U:
1457
1458           This variable conditionally defines the "HAS_FP_CLASSIFY" symbol,
1459           which indicates to the C program that the fp_classify() routine is
1460           available.
1461
1462       "d_fp_classl"
1463           From d_fp_classl.U:
1464
1465           This variable conditionally defines the "HAS_FP_CLASSL" symbol,
1466           which indicates to the C program that the fp_classl() routine is
1467           available.
1468
1469       "d_fpathconf"
1470           From d_pathconf.U:
1471
1472           This variable conditionally defines the "HAS_FPATHCONF" symbol,
1473           which indicates to the C program that the pathconf() routine is
1474           available to determine file-system related limits and options
1475           associated with a given open file descriptor.
1476
1477       "d_fpclass"
1478           From d_fpclass.U:
1479
1480           This variable conditionally defines the "HAS_FPCLASS" symbol, which
1481           indicates to the C program that the fpclass() routine is available.
1482
1483       "d_fpclassify"
1484           From d_fpclassify.U:
1485
1486           This variable conditionally defines the "HAS_FPCLASSIFY" symbol,
1487           which indicates to the C program that the fpclassify() routine is
1488           available.
1489
1490       "d_fpclassl"
1491           From d_fpclassl.U:
1492
1493           This variable conditionally defines the "HAS_FPCLASSL" symbol,
1494           which indicates to the C program that the fpclassl() routine is
1495           available.
1496
1497       "d_fpgetround"
1498           From d_fpgetround.U:
1499
1500           This variable conditionally defines "HAS_FPGETROUND" if
1501           fpgetround() is available to get the floating point rounding mode.
1502
1503       "d_fpos64_t"
1504           From d_fpos64_t.U:
1505
1506           This symbol will be defined if the C compiler supports fpos64_t.
1507
1508       "d_freelocale"
1509           From d_newlocale.U:
1510
1511           This variable conditionally defines the "HAS_FREELOCALE" symbol,
1512           which indicates to the C program that the freelocale() routine is
1513           available to deallocates the resources associated with a locale
1514           object.
1515
1516       "d_frexpl"
1517           From d_frexpl.U:
1518
1519           This variable conditionally defines the "HAS_FREXPL" symbol, which
1520           indicates to the C program that the frexpl() routine is available.
1521
1522       "d_fs_data_s"
1523           From d_fs_data_s.U:
1524
1525           This variable conditionally defines the "HAS_STRUCT_FS_DATA"
1526           symbol, which indicates that the struct fs_data is supported.
1527
1528       "d_fseeko"
1529           From d_fseeko.U:
1530
1531           This variable conditionally defines the "HAS_FSEEKO" symbol, which
1532           indicates to the C program that the fseeko() routine is available.
1533
1534       "d_fsetpos"
1535           From d_fsetpos.U:
1536
1537           This variable conditionally defines "HAS_FSETPOS" if fsetpos() is
1538           available to set the file position indicator.
1539
1540       "d_fstatfs"
1541           From d_fstatfs.U:
1542
1543           This variable conditionally defines the "HAS_FSTATFS" symbol, which
1544           indicates to the C program that the fstatfs() routine is available.
1545
1546       "d_fstatvfs"
1547           From d_statvfs.U:
1548
1549           This variable conditionally defines the "HAS_FSTATVFS" symbol,
1550           which indicates to the C program that the fstatvfs() routine is
1551           available.
1552
1553       "d_fsync"
1554           From d_fsync.U:
1555
1556           This variable conditionally defines the "HAS_FSYNC" symbol, which
1557           indicates to the C program that the fsync() routine is available.
1558
1559       "d_ftello"
1560           From d_ftello.U:
1561
1562           This variable conditionally defines the "HAS_FTELLO" symbol, which
1563           indicates to the C program that the ftello() routine is available.
1564
1565       "d_ftime"
1566           From d_ftime.U:
1567
1568           This variable conditionally defines the "HAS_FTIME" symbol, which
1569           indicates that the ftime() routine exists.  The ftime() routine is
1570           basically a sub-second accuracy clock.
1571
1572       "d_futimes"
1573           From d_futimes.U:
1574
1575           This variable conditionally defines the "HAS_FUTIMES" symbol, which
1576           indicates to the C program that the futimes() routine is available.
1577
1578       "d_gai_strerror"
1579           From d_gai_strerror.U:
1580
1581           This variable conditionally defines the "HAS_GAI_STRERROR" symbol
1582           if the gai_strerror() routine is available and can be used to
1583           translate error codes returned by getaddrinfo() into human readable
1584           strings.
1585
1586       "d_Gconvert"
1587           From d_gconvert.U:
1588
1589           This variable holds what Gconvert is defined as to convert floating
1590           point numbers into strings.  By default, Configure sets "this"
1591           macro to use the first of gconvert, gcvt, or sprintf that pass
1592           sprintf-%g-like behavior tests.  If perl is using long doubles, the
1593           macro uses the first of the following functions that pass
1594           Configure's tests: qgcvt, sprintf (if Configure knows how to make
1595           sprintf format long doubles--see sPRIgldbl), gconvert, gcvt, and
1596           sprintf (casting to double).  The gconvert_preference and
1597           gconvert_ld_preference variables can be used to alter Configure's
1598           preferences, for doubles and long doubles, respectively.  If
1599           present, they contain a space-separated list of one or more of the
1600           above function names in the order they should be tried.
1601
1602           d_Gconvert may be set to override Configure with a platform-
1603           specific function.  If this function expects a double, a different
1604           value may need to be set by the uselongdouble.cbu call-back unit so
1605           that long doubles can be formatted without loss of precision.
1606
1607       "d_gdbm_ndbm_h_uses_prototypes"
1608           From i_ndbm.U:
1609
1610           This variable conditionally defines the "NDBM_H_USES_PROTOTYPES"
1611           symbol, which indicates that the gdbm-ndbm.h include file uses real
1612           "ANSI" C prototypes instead of K&R style function declarations. K&R
1613           style declarations are unsupported in C++, so the include file
1614           requires special handling when using a C++ compiler and this
1615           variable is undefined. Consult the different
1616           d_*ndbm_h_uses_prototypes variables to get the same information for
1617           alternative ndbm.h include files.
1618
1619       "d_gdbmndbm_h_uses_prototypes"
1620           From i_ndbm.U:
1621
1622           This variable conditionally defines the "NDBM_H_USES_PROTOTYPES"
1623           symbol, which indicates that the gdbm/ndbm.h include file uses real
1624           "ANSI" C prototypes instead of K&R style function declarations. K&R
1625           style declarations are unsupported in C++, so the include file
1626           requires special handling when using a C++ compiler and this
1627           variable is undefined. Consult the different
1628           d_*ndbm_h_uses_prototypes variables to get the same information for
1629           alternative ndbm.h include files.
1630
1631       "d_getaddrinfo"
1632           From d_getaddrinfo.U:
1633
1634           This variable conditionally defines the "HAS_GETADDRINFO" symbol,
1635           which indicates to the C program that the getaddrinfo() function is
1636           available.
1637
1638       "d_getcwd"
1639           From d_getcwd.U:
1640
1641           This variable conditionally defines the "HAS_GETCWD" symbol, which
1642           indicates to the C program that the getcwd() routine is available
1643           to get the current working directory.
1644
1645       "d_getespwnam"
1646           From d_getespwnam.U:
1647
1648           This variable conditionally defines "HAS_GETESPWNAM" if
1649           getespwnam() is available to retrieve enhanced (shadow) password
1650           entries by name.
1651
1652       "d_getfsstat"
1653           From d_getfsstat.U:
1654
1655           This variable conditionally defines the "HAS_GETFSSTAT" symbol,
1656           which indicates to the C program that the getfsstat() routine is
1657           available.
1658
1659       "d_getgrent"
1660           From d_getgrent.U:
1661
1662           This variable conditionally defines the "HAS_GETGRENT" symbol,
1663           which indicates to the C program that the getgrent() routine is
1664           available for sequential access of the group database.
1665
1666       "d_getgrent_r"
1667           From d_getgrent_r.U:
1668
1669           This variable conditionally defines the "HAS_GETGRENT_R" symbol,
1670           which indicates to the C program that the getgrent_r() routine is
1671           available.
1672
1673       "d_getgrgid_r"
1674           From d_getgrgid_r.U:
1675
1676           This variable conditionally defines the "HAS_GETGRGID_R" symbol,
1677           which indicates to the C program that the getgrgid_r() routine is
1678           available.
1679
1680       "d_getgrnam_r"
1681           From d_getgrnam_r.U:
1682
1683           This variable conditionally defines the "HAS_GETGRNAM_R" symbol,
1684           which indicates to the C program that the getgrnam_r() routine is
1685           available.
1686
1687       "d_getgrps"
1688           From d_getgrps.U:
1689
1690           This variable conditionally defines the "HAS_GETGROUPS" symbol,
1691           which indicates to the C program that the getgroups() routine is
1692           available to get the list of process groups.
1693
1694       "d_gethbyaddr"
1695           From d_gethbyad.U:
1696
1697           This variable conditionally defines the "HAS_GETHOSTBYADDR" symbol,
1698           which indicates to the C program that the gethostbyaddr() routine
1699           is available to look up hosts by their "IP" addresses.
1700
1701       "d_gethbyname"
1702           From d_gethbynm.U:
1703
1704           This variable conditionally defines the "HAS_GETHOSTBYNAME" symbol,
1705           which indicates to the C program that the gethostbyname() routine
1706           is available to look up host names in some data base or other.
1707
1708       "d_gethent"
1709           From d_gethent.U:
1710
1711           This variable conditionally defines "HAS_GETHOSTENT" if
1712           gethostent() is available to look up host names in some data base
1713           or another.
1714
1715       "d_gethname"
1716           From d_gethname.U:
1717
1718           This variable conditionally defines the "HAS_GETHOSTNAME" symbol,
1719           which indicates to the C program that the gethostname() routine may
1720           be used to derive the host name.
1721
1722       "d_gethostbyaddr_r"
1723           From d_gethostbyaddr_r.U:
1724
1725           This variable conditionally defines the "HAS_GETHOSTBYADDR_R"
1726           symbol, which indicates to the C program that the gethostbyaddr_r()
1727           routine is available.
1728
1729       "d_gethostbyname_r"
1730           From d_gethostbyname_r.U:
1731
1732           This variable conditionally defines the "HAS_GETHOSTBYNAME_R"
1733           symbol, which indicates to the C program that the gethostbyname_r()
1734           routine is available.
1735
1736       "d_gethostent_r"
1737           From d_gethostent_r.U:
1738
1739           This variable conditionally defines the "HAS_GETHOSTENT_R" symbol,
1740           which indicates to the C program that the gethostent_r() routine is
1741           available.
1742
1743       "d_gethostprotos"
1744           From d_gethostprotos.U:
1745
1746           This variable conditionally defines the "HAS_GETHOST_PROTOS"
1747           symbol, which indicates to the C program that <netdb.h> supplies
1748           prototypes for the various gethost*() functions.  See also
1749           netdbtype.U for probing for various netdb types.
1750
1751       "d_getitimer"
1752           From d_getitimer.U:
1753
1754           This variable conditionally defines the "HAS_GETITIMER" symbol,
1755           which indicates to the C program that the getitimer() routine is
1756           available.
1757
1758       "d_getlogin"
1759           From d_getlogin.U:
1760
1761           This variable conditionally defines the "HAS_GETLOGIN" symbol,
1762           which indicates to the C program that the getlogin() routine is
1763           available to get the login name.
1764
1765       "d_getlogin_r"
1766           From d_getlogin_r.U:
1767
1768           This variable conditionally defines the "HAS_GETLOGIN_R" symbol,
1769           which indicates to the C program that the getlogin_r() routine is
1770           available.
1771
1772       "d_getmnt"
1773           From d_getmnt.U:
1774
1775           This variable conditionally defines the "HAS_GETMNT" symbol, which
1776           indicates to the C program that the getmnt() routine is available
1777           to retrieve one or more mount info blocks by filename.
1778
1779       "d_getmntent"
1780           From d_getmntent.U:
1781
1782           This variable conditionally defines the "HAS_GETMNTENT" symbol,
1783           which indicates to the C program that the getmntent() routine is
1784           available to iterate through mounted files to get their mount info.
1785
1786       "d_getnameinfo"
1787           From d_getnameinfo.U:
1788
1789           This variable conditionally defines the "HAS_GETNAMEINFO" symbol,
1790           which indicates to the C program that the getnameinfo() function is
1791           available.
1792
1793       "d_getnbyaddr"
1794           From d_getnbyad.U:
1795
1796           This variable conditionally defines the "HAS_GETNETBYADDR" symbol,
1797           which indicates to the C program that the getnetbyaddr() routine is
1798           available to look up networks by their "IP" addresses.
1799
1800       "d_getnbyname"
1801           From d_getnbynm.U:
1802
1803           This variable conditionally defines the "HAS_GETNETBYNAME" symbol,
1804           which indicates to the C program that the getnetbyname() routine is
1805           available to look up networks by their names.
1806
1807       "d_getnent"
1808           From d_getnent.U:
1809
1810           This variable conditionally defines "HAS_GETNETENT" if getnetent()
1811           is available to look up network names in some data base or another.
1812
1813       "d_getnetbyaddr_r"
1814           From d_getnetbyaddr_r.U:
1815
1816           This variable conditionally defines the "HAS_GETNETBYADDR_R"
1817           symbol, which indicates to the C program that the getnetbyaddr_r()
1818           routine is available.
1819
1820       "d_getnetbyname_r"
1821           From d_getnetbyname_r.U:
1822
1823           This variable conditionally defines the "HAS_GETNETBYNAME_R"
1824           symbol, which indicates to the C program that the getnetbyname_r()
1825           routine is available.
1826
1827       "d_getnetent_r"
1828           From d_getnetent_r.U:
1829
1830           This variable conditionally defines the "HAS_GETNETENT_R" symbol,
1831           which indicates to the C program that the getnetent_r() routine is
1832           available.
1833
1834       "d_getnetprotos"
1835           From d_getnetprotos.U:
1836
1837           This variable conditionally defines the "HAS_GETNET_PROTOS" symbol,
1838           which indicates to the C program that <netdb.h> supplies prototypes
1839           for the various getnet*() functions.  See also netdbtype.U for
1840           probing for various netdb types.
1841
1842       "d_getpagsz"
1843           From d_getpagsz.U:
1844
1845           This variable conditionally defines "HAS_GETPAGESIZE" if
1846           getpagesize() is available to get the system page size.
1847
1848       "d_getpbyname"
1849           From d_getprotby.U:
1850
1851           This variable conditionally defines the "HAS_GETPROTOBYNAME"
1852           symbol, which indicates to the C program that the getprotobyname()
1853           routine is available to look up protocols by their name.
1854
1855       "d_getpbynumber"
1856           From d_getprotby.U:
1857
1858           This variable conditionally defines the "HAS_GETPROTOBYNUMBER"
1859           symbol, which indicates to the C program that the
1860           getprotobynumber() routine is available to look up protocols by
1861           their number.
1862
1863       "d_getpent"
1864           From d_getpent.U:
1865
1866           This variable conditionally defines "HAS_GETPROTOENT" if
1867           getprotoent() is available to look up protocols in some data base
1868           or another.
1869
1870       "d_getpgid"
1871           From d_getpgid.U:
1872
1873           This variable conditionally defines the "HAS_GETPGID" symbol, which
1874           indicates to the C program that the getpgid(pid) function is
1875           available to get the process group id.
1876
1877       "d_getpgrp"
1878           From d_getpgrp.U:
1879
1880           This variable conditionally defines "HAS_GETPGRP" if getpgrp() is
1881           available to get the current process group.
1882
1883       "d_getpgrp2"
1884           From d_getpgrp2.U:
1885
1886           This variable conditionally defines the HAS_GETPGRP2 symbol, which
1887           indicates to the C program that the getpgrp2() (as in DG/"UX")
1888           routine is available to get the current process group.
1889
1890       "d_getppid"
1891           From d_getppid.U:
1892
1893           This variable conditionally defines the "HAS_GETPPID" symbol, which
1894           indicates to the C program that the getppid() routine is available
1895           to get the parent process "ID".
1896
1897       "d_getprior"
1898           From d_getprior.U:
1899
1900           This variable conditionally defines "HAS_GETPRIORITY" if
1901           getpriority() is available to get a process's priority.
1902
1903       "d_getprotobyname_r"
1904           From d_getprotobyname_r.U:
1905
1906           This variable conditionally defines the "HAS_GETPROTOBYNAME_R"
1907           symbol, which indicates to the C program that the
1908           getprotobyname_r() routine is available.
1909
1910       "d_getprotobynumber_r"
1911           From d_getprotobynumber_r.U:
1912
1913           This variable conditionally defines the "HAS_GETPROTOBYNUMBER_R"
1914           symbol, which indicates to the C program that the
1915           getprotobynumber_r() routine is available.
1916
1917       "d_getprotoent_r"
1918           From d_getprotoent_r.U:
1919
1920           This variable conditionally defines the "HAS_GETPROTOENT_R" symbol,
1921           which indicates to the C program that the getprotoent_r() routine
1922           is available.
1923
1924       "d_getprotoprotos"
1925           From d_getprotoprotos.U:
1926
1927           This variable conditionally defines the "HAS_GETPROTO_PROTOS"
1928           symbol, which indicates to the C program that <netdb.h> supplies
1929           prototypes for the various getproto*() functions.  See also
1930           netdbtype.U for probing for various netdb types.
1931
1932       "d_getprpwnam"
1933           From d_getprpwnam.U:
1934
1935           This variable conditionally defines "HAS_GETPRPWNAM" if
1936           getprpwnam() is available to retrieve protected (shadow) password
1937           entries by name.
1938
1939       "d_getpwent"
1940           From d_getpwent.U:
1941
1942           This variable conditionally defines the "HAS_GETPWENT" symbol,
1943           which indicates to the C program that the getpwent() routine is
1944           available for sequential access of the passwd database.
1945
1946       "d_getpwent_r"
1947           From d_getpwent_r.U:
1948
1949           This variable conditionally defines the "HAS_GETPWENT_R" symbol,
1950           which indicates to the C program that the getpwent_r() routine is
1951           available.
1952
1953       "d_getpwnam_r"
1954           From d_getpwnam_r.U:
1955
1956           This variable conditionally defines the "HAS_GETPWNAM_R" symbol,
1957           which indicates to the C program that the getpwnam_r() routine is
1958           available.
1959
1960       "d_getpwuid_r"
1961           From d_getpwuid_r.U:
1962
1963           This variable conditionally defines the "HAS_GETPWUID_R" symbol,
1964           which indicates to the C program that the getpwuid_r() routine is
1965           available.
1966
1967       "d_getsbyname"
1968           From d_getsrvby.U:
1969
1970           This variable conditionally defines the "HAS_GETSERVBYNAME" symbol,
1971           which indicates to the C program that the getservbyname() routine
1972           is available to look up services by their name.
1973
1974       "d_getsbyport"
1975           From d_getsrvby.U:
1976
1977           This variable conditionally defines the "HAS_GETSERVBYPORT" symbol,
1978           which indicates to the C program that the getservbyport() routine
1979           is available to look up services by their port.
1980
1981       "d_getsent"
1982           From d_getsent.U:
1983
1984           This variable conditionally defines "HAS_GETSERVENT" if
1985           getservent() is available to look up network services in some data
1986           base or another.
1987
1988       "d_getservbyname_r"
1989           From d_getservbyname_r.U:
1990
1991           This variable conditionally defines the "HAS_GETSERVBYNAME_R"
1992           symbol, which indicates to the C program that the getservbyname_r()
1993           routine is available.
1994
1995       "d_getservbyport_r"
1996           From d_getservbyport_r.U:
1997
1998           This variable conditionally defines the "HAS_GETSERVBYPORT_R"
1999           symbol, which indicates to the C program that the getservbyport_r()
2000           routine is available.
2001
2002       "d_getservent_r"
2003           From d_getservent_r.U:
2004
2005           This variable conditionally defines the "HAS_GETSERVENT_R" symbol,
2006           which indicates to the C program that the getservent_r() routine is
2007           available.
2008
2009       "d_getservprotos"
2010           From d_getservprotos.U:
2011
2012           This variable conditionally defines the "HAS_GETSERV_PROTOS"
2013           symbol, which indicates to the C program that <netdb.h> supplies
2014           prototypes for the various getserv*() functions.  See also
2015           netdbtype.U for probing for various netdb types.
2016
2017       "d_getspnam"
2018           From d_getspnam.U:
2019
2020           This variable conditionally defines "HAS_GETSPNAM" if getspnam() is
2021           available to retrieve SysV shadow password entries by name.
2022
2023       "d_getspnam_r"
2024           From d_getspnam_r.U:
2025
2026           This variable conditionally defines the "HAS_GETSPNAM_R" symbol,
2027           which indicates to the C program that the getspnam_r() routine is
2028           available.
2029
2030       "d_gettimeod"
2031           From d_ftime.U:
2032
2033           This variable conditionally defines the "HAS_GETTIMEOFDAY" symbol,
2034           which indicates that the gettimeofday() system call exists (to
2035           obtain a sub-second accuracy clock). You should probably include
2036           <sys/resource.h>.
2037
2038       "d_gmtime64"
2039           From d_timefuncs64.U:
2040
2041           This variable conditionally defines the HAS_GMTIME64 symbol, which
2042           indicates to the C program that the gmtime64 () routine is
2043           available.
2044
2045       "d_gmtime_r"
2046           From d_gmtime_r.U:
2047
2048           This variable conditionally defines the "HAS_GMTIME_R" symbol,
2049           which indicates to the C program that the gmtime_r() routine is
2050           available.
2051
2052       "d_gnulibc"
2053           From d_gnulibc.U:
2054
2055           Defined if we're dealing with the "GNU" C Library.
2056
2057       "d_grpasswd"
2058           From i_grp.U:
2059
2060           This variable conditionally defines "GRPASSWD", which indicates
2061           that struct group in <grp.h> contains gr_passwd.
2062
2063       "d_hasmntopt"
2064           From d_hasmntopt.U:
2065
2066           This variable conditionally defines the "HAS_HASMNTOPT" symbol,
2067           which indicates to the C program that the hasmntopt() routine is
2068           available to query the mount options of file systems.
2069
2070       "d_htonl"
2071           From d_htonl.U:
2072
2073           This variable conditionally defines "HAS_HTONL" if htonl() and its
2074           friends are available to do network order byte swapping.
2075
2076       "d_hypot"
2077           From d_hypot.U:
2078
2079           This variable conditionally defines "HAS_HYPOT" if hypot is
2080           available for numerically stable hypotenuse function.
2081
2082       "d_ilogb"
2083           From d_ilogb.U:
2084
2085           This variable conditionally defines the "HAS_ILOGB" symbol, which
2086           indicates to the C program that the ilogb() routine is available
2087           for extracting the exponent of double x as a signed integer.
2088
2089       "d_ilogbl"
2090           From d_ilogbl.U:
2091
2092           This variable conditionally defines the "HAS_ILOGBL" symbol, which
2093           indicates to the C program that the ilogbl() routine is available
2094           for extracting the exponent of long double x as a signed integer.
2095           If scalbnl is also present we can emulate frexpl.
2096
2097       "d_inc_version_list"
2098           From inc_version_list.U:
2099
2100           This variable conditionally defines "PERL_INC_VERSION_LIST".  It is
2101           set to undef when "PERL_INC_VERSION_LIST" is empty.
2102
2103       "d_index"
2104           From d_strchr.U:
2105
2106           This variable conditionally defines "HAS_INDEX" if index() and
2107           rindex() are available for string searching.
2108
2109       "d_inetaton"
2110           From d_inetaton.U:
2111
2112           This variable conditionally defines the "HAS_INET_ATON" symbol,
2113           which indicates to the C program that the inet_aton() function is
2114           available to parse "IP" address "dotted-quad" strings.
2115
2116       "d_inetntop"
2117           From d_inetntop.U:
2118
2119           This variable conditionally defines the "HAS_INETNTOP" symbol,
2120           which indicates to the C program that the inet_ntop() function is
2121           available.
2122
2123       "d_inetpton"
2124           From d_inetpton.U:
2125
2126           This variable conditionally defines the "HAS_INETPTON" symbol,
2127           which indicates to the C program that the inet_pton() function is
2128           available.
2129
2130       "d_int64_t"
2131           From d_int64_t.U:
2132
2133           This symbol will be defined if the C compiler supports int64_t.
2134
2135       "d_ip_mreq"
2136           From d_socket.U:
2137
2138           This variable conditionally defines the "HAS_IP_MREQ" symbol, which
2139           indicates the availability of a struct ip_mreq.
2140
2141       "d_ip_mreq_source"
2142           From d_socket.U:
2143
2144           This variable conditionally defines the "HAS_IP_MREQ_SOURCE"
2145           symbol, which indicates the availability of a struct
2146           ip_mreq_source.
2147
2148       "d_ipv6_mreq"
2149           From d_socket.U:
2150
2151           This variable conditionally defines the HAS_IPV6_MREQ symbol, which
2152           indicates the availability of a struct ipv6_mreq.
2153
2154       "d_ipv6_mreq_source"
2155           From d_socket.U:
2156
2157           This variable conditionally defines the HAS_IPV6_MREQ_SOURCE
2158           symbol, which indicates the availability of a struct
2159           ipv6_mreq_source.
2160
2161       "d_isascii"
2162           From d_isascii.U:
2163
2164           This variable conditionally defines the "HAS_ISASCII" constant,
2165           which indicates to the C program that isascii() is available.
2166
2167       "d_isblank"
2168           From d_isblank.U:
2169
2170           This variable conditionally defines the "HAS_ISBLANK" constant,
2171           which indicates to the C program that isblank() is available.
2172
2173       "d_isfinite"
2174           From d_isfinite.U:
2175
2176           This variable conditionally defines the "HAS_ISFINITE" symbol,
2177           which indicates to the C program that the isfinite() routine is
2178           available.
2179
2180       "d_isfinitel"
2181           From d_isfinitel.U:
2182
2183           This variable conditionally defines the "HAS_ISFINITEL" symbol,
2184           which indicates to the C program that the isfinitel() routine is
2185           available.
2186
2187       "d_isinf"
2188           From d_isinf.U:
2189
2190           This variable conditionally defines the "HAS_ISINF" symbol, which
2191           indicates to the C program that the isinf() routine is available.
2192
2193       "d_isinfl"
2194           From d_isinfl.U:
2195
2196           This variable conditionally defines the "HAS_ISINFL" symbol, which
2197           indicates to the C program that the isinfl() routine is available.
2198
2199       "d_isless"
2200           From d_isless.U:
2201
2202           This variable conditionally defines the "HAS_ISLESS" symbol, which
2203           indicates to the C program that the isless() routine is available.
2204
2205       "d_isnan"
2206           From d_isnan.U:
2207
2208           This variable conditionally defines the "HAS_ISNAN" symbol, which
2209           indicates to the C program that the isnan() routine is available.
2210
2211       "d_isnanl"
2212           From d_isnanl.U:
2213
2214           This variable conditionally defines the "HAS_ISNANL" symbol, which
2215           indicates to the C program that the isnanl() routine is available.
2216
2217       "d_isnormal"
2218           From d_isnormal.U:
2219
2220           This variable conditionally defines the "HAS_ISNORMAL" symbol,
2221           which indicates to the C program that the isnormal() routine is
2222           available.
2223
2224       "d_j0"
2225           From d_j0.U:
2226
2227           This variable conditionally defines the HAS_J0 symbol, which
2228           indicates to the C program that the j0() routine is available.
2229
2230       "d_j0l"
2231           From d_j0.U:
2232
2233           This variable conditionally defines the HAS_J0L symbol, which
2234           indicates to the C program that the j0l() routine is available.
2235
2236       "d_killpg"
2237           From d_killpg.U:
2238
2239           This variable conditionally defines the "HAS_KILLPG" symbol, which
2240           indicates to the C program that the killpg() routine is available
2241           to kill process groups.
2242
2243       "d_lc_monetary_2008"
2244           From d_lc_monetary_2008.U:
2245
2246           This variable conditionally defines HAS_LC_MONETARY_2008 if libc
2247           has the international currency locale rules from "POSIX"
2248           1003.1-2008.
2249
2250       "d_lchown"
2251           From d_lchown.U:
2252
2253           This variable conditionally defines the "HAS_LCHOWN" symbol, which
2254           indicates to the C program that the lchown() routine is available
2255           to operate on a symbolic link (instead of following the link).
2256
2257       "d_ldbl_dig"
2258           From d_ldbl_dig.U:
2259
2260           This variable conditionally defines d_ldbl_dig if this system's
2261           header files provide "LDBL_DIG", which is the number of significant
2262           digits in a long double precision number.
2263
2264       "d_ldexpl"
2265           From d_longdbl.U:
2266
2267           This variable conditionally defines the "HAS_LDEXPL" symbol, which
2268           indicates to the C program that the ldexpl() routine is available.
2269
2270       "d_lgamma"
2271           From d_lgamma.U:
2272
2273           This variable conditionally defines the "HAS_LGAMMA" symbol, which
2274           indicates to the C program that the lgamma() routine is available
2275           for the log gamma function.  See also d_tgamma and d_lgamma_r.
2276
2277       "d_lgamma_r"
2278           From d_lgamma_r.U:
2279
2280           This variable conditionally defines the "HAS_LGAMMA_R" symbol,
2281           which indicates to the C program that the lgamma_r() routine is
2282           available for the log gamma function, without using the global
2283           signgam variable.
2284
2285       "d_libm_lib_version"
2286           From d_libm_lib_version.U:
2287
2288           This variable conditionally defines the "LIBM_LIB_VERSION" symbol,
2289           which indicates to the C program that math.h defines "_LIB_VERSION"
2290           being available in libm
2291
2292       "d_libname_unique"
2293           From so.U:
2294
2295           This variable is defined if the target system insists on unique
2296           basenames for shared library files. This is currently true on
2297           Android, false everywhere else we know of.  Defaults to "undef".
2298
2299       "d_link"
2300           From d_link.U:
2301
2302           This variable conditionally defines "HAS_LINK" if link() is
2303           available to create hard links.
2304
2305       "d_llrint"
2306           From d_llrint.U:
2307
2308           This variable conditionally defines the "HAS_LLRINT" symbol, which
2309           indicates to the C program that the llrint() routine is available
2310           to return the long long value closest to a double (according to the
2311           current rounding mode).
2312
2313       "d_llrintl"
2314           From d_llrintl.U:
2315
2316           This variable conditionally defines the "HAS_LLRINTL" symbol, which
2317           indicates to the C program that the llrintl() routine is available
2318           to return the long long value closest to a long double (according
2319           to the current rounding mode).
2320
2321       "d_llround"
2322           From d_llround.U:
2323
2324           This variable conditionally defines the "HAS_LLROUND" symbol, which
2325           indicates to the C program that the llround() routine is available
2326           to return the long long value nearest to x.
2327
2328       "d_llroundl"
2329           From d_llroundl.U:
2330
2331           This variable conditionally defines the "HAS_LLROUNDL" symbol,
2332           which indicates to the C program that the llroundl() routine is
2333           available to return the long long value nearest to x away from
2334           zero.
2335
2336       "d_localtime64"
2337           From d_timefuncs64.U:
2338
2339           This variable conditionally defines the HAS_LOCALTIME64 symbol,
2340           which indicates to the C program that the localtime64 () routine is
2341           available.
2342
2343       "d_localtime_r"
2344           From d_localtime_r.U:
2345
2346           This variable conditionally defines the "HAS_LOCALTIME_R" symbol,
2347           which indicates to the C program that the localtime_r() routine is
2348           available.
2349
2350       "d_localtime_r_needs_tzset"
2351           From d_localtime_r.U:
2352
2353           This variable conditionally defines the "LOCALTIME_R_NEEDS_TZSET"
2354           symbol, which makes us call tzset before localtime_r()
2355
2356       "d_locconv"
2357           From d_locconv.U:
2358
2359           This variable conditionally defines "HAS_LOCALECONV" if
2360           localeconv() is available for numeric and monetary formatting
2361           conventions.
2362
2363       "d_lockf"
2364           From d_lockf.U:
2365
2366           This variable conditionally defines "HAS_LOCKF" if lockf() is
2367           available to do file locking.
2368
2369       "d_log1p"
2370           From d_log1p.U:
2371
2372           This variable conditionally defines the HAS_LOG1P symbol, which
2373           indicates to the C program that the logp1() routine is available to
2374           compute log(1 + x) for values of x close to zero.
2375
2376       "d_log2"
2377           From d_log2.U:
2378
2379           This variable conditionally defines the HAS_LOG2 symbol, which
2380           indicates to the C program that the log2() routine is available to
2381           compute log base two.
2382
2383       "d_logb"
2384           From d_logb.U:
2385
2386           This variable conditionally defines the "HAS_LOGB" symbol, which
2387           indicates to the C program that the logb() routine is available to
2388           extract the exponent of x.
2389
2390       "d_longdbl"
2391           From d_longdbl.U:
2392
2393           This variable conditionally defines "HAS_LONG_DOUBLE" if the long
2394           double type is supported.
2395
2396       "d_long_double_style_ieee"
2397           From d_longdbl.U:
2398
2399           This variable conditionally defines "LONG_DOUBLE_STYLE_IEEE" if the
2400           long double is any of the "IEEE" 754 style long doubles:
2401           "LONG_DOUBLE_STYLE_IEEE_STD", "LONG_DOUBLE_STYLE_IEEE_EXTENDED",
2402           "LONG_DOUBLE_STYLE_IEEE_DOUBLEDOUBLE".
2403
2404       "d_long_double_style_ieee_doubledouble"
2405           From d_longdbl.U:
2406
2407           This variable conditionally defines
2408           "LONG_DOUBLE_STYLE_IEEE_DOUBLEDOUBLE" if the long double is the
2409           128-bit "IEEE" 754 double-double.
2410
2411       "d_long_double_style_ieee_extended"
2412           From d_longdbl.U:
2413
2414           This variable conditionally defines
2415           "LONG_DOUBLE_STYLE_IEEE_EXTENDED" if the long double is the 80-bit
2416           "IEEE" 754 extended precision.  Note that despite the "extended"
2417           this is less than the "std", since thisis an extension of the
2418           double precision.
2419
2420       "d_long_double_style_ieee_std"
2421           From d_longdbl.U:
2422
2423           This variable conditionally defines "LONG_DOUBLE_STYLE_IEEE_STD" if
2424           the long double is the 128-bit "IEEE" 754.
2425
2426       "d_long_double_style_vax"
2427           From d_longdbl.U:
2428
2429           This variable conditionally defines "LONG_DOUBLE_STYLE_VAX" if the
2430           long double is the 128-bit "VAX" format H.
2431
2432       "d_longlong"
2433           From d_longlong.U:
2434
2435           This variable conditionally defines "HAS_LONG_LONG" if the long
2436           long type is supported.
2437
2438       "d_lrint"
2439           From d_lrint.U:
2440
2441           This variable conditionally defines the "HAS_LRINT" symbol, which
2442           indicates to the C program that the lrint() routine is available to
2443           return the integral value closest to a double (according to the
2444           current rounding mode).
2445
2446       "d_lrintl"
2447           From d_lrintl.U:
2448
2449           This variable conditionally defines the "HAS_LRINTL" symbol, which
2450           indicates to the C program that the lrintl() routine is available
2451           to return the integral value closest to a long double (according to
2452           the current rounding mode).
2453
2454       "d_lround"
2455           From d_lround.U:
2456
2457           This variable conditionally defines the "HAS_LROUND" symbol, which
2458           indicates to the C program that the lround() routine is available
2459           to return the integral value nearest to x.
2460
2461       "d_lroundl"
2462           From d_lroundl.U:
2463
2464           This variable conditionally defines the "HAS_LROUNDL" symbol, which
2465           indicates to the C program that the lroundl() routine is available
2466           to return the integral value nearest to x away from zero.
2467
2468       "d_lseekproto"
2469           From d_lseekproto.U:
2470
2471           This variable conditionally defines the "HAS_LSEEK_PROTO" symbol,
2472           which indicates to the C program that the system provides a
2473           prototype for the lseek() function.  Otherwise, it is up to the
2474           program to supply one.
2475
2476       "d_lstat"
2477           From d_lstat.U:
2478
2479           This variable conditionally defines "HAS_LSTAT" if lstat() is
2480           available to do file stats on symbolic links.
2481
2482       "d_madvise"
2483           From d_madvise.U:
2484
2485           This variable conditionally defines "HAS_MADVISE" if madvise() is
2486           available to map a file into memory.
2487
2488       "d_malloc_good_size"
2489           From d_malloc_size.U:
2490
2491           This symbol, if defined, indicates that the malloc_good_size
2492           routine is available for use.
2493
2494       "d_malloc_size"
2495           From d_malloc_size.U:
2496
2497           This symbol, if defined, indicates that the malloc_size routine is
2498           available for use.
2499
2500       "d_mblen"
2501           From d_mblen.U:
2502
2503           This variable conditionally defines the "HAS_MBLEN" symbol, which
2504           indicates to the C program that the mblen() routine is available to
2505           find the number of bytes in a multibye character.
2506
2507       "d_mbstowcs"
2508           From d_mbstowcs.U:
2509
2510           This variable conditionally defines the "HAS_MBSTOWCS" symbol,
2511           which indicates to the C program that the mbstowcs() routine is
2512           available to convert a multibyte string into a wide character
2513           string.
2514
2515       "d_mbtowc"
2516           From d_mbtowc.U:
2517
2518           This variable conditionally defines the "HAS_MBTOWC" symbol, which
2519           indicates to the C program that the mbtowc() routine is available
2520           to convert multibyte to a wide character.
2521
2522       "d_memchr"
2523           From d_memchr.U:
2524
2525           This variable conditionally defines the "HAS_MEMCHR" symbol, which
2526           indicates to the C program that the memchr() routine is available
2527           to locate characters within a C string.
2528
2529       "d_memcmp"
2530           From d_memcmp.U:
2531
2532           This variable conditionally defines the "HAS_MEMCMP" symbol, which
2533           indicates to the C program that the memcmp() routine is available
2534           to compare blocks of memory.
2535
2536       "d_memcpy"
2537           From d_memcpy.U:
2538
2539           This variable conditionally defines the "HAS_MEMCPY" symbol, which
2540           indicates to the C program that the memcpy() routine is available
2541           to copy blocks of memory.
2542
2543       "d_memmem"
2544           From d_memmem.U:
2545
2546           This variable conditionally defines the "HAS_MEMMEM" symbol, which
2547           indicates to the C program that the memmem() routine is available
2548           to return a pointer to the start of the first occurance of a
2549           substring in a memory area (or "NULL" if not found).
2550
2551       "d_memmove"
2552           From d_memmove.U:
2553
2554           This variable conditionally defines the "HAS_MEMMOVE" symbol, which
2555           indicates to the C program that the memmove() routine is available
2556           to copy potentially overlapping blocks of memory.
2557
2558       "d_memset"
2559           From d_memset.U:
2560
2561           This variable conditionally defines the "HAS_MEMSET" symbol, which
2562           indicates to the C program that the memset() routine is available
2563           to set blocks of memory.
2564
2565       "d_mkdir"
2566           From d_mkdir.U:
2567
2568           This variable conditionally defines the "HAS_MKDIR" symbol, which
2569           indicates to the C program that the mkdir() routine is available to
2570           create directories..
2571
2572       "d_mkdtemp"
2573           From d_mkdtemp.U:
2574
2575           This variable conditionally defines the "HAS_MKDTEMP" symbol, which
2576           indicates to the C program that the mkdtemp() routine is available
2577           to exclusively create a uniquely named temporary directory.
2578
2579       "d_mkfifo"
2580           From d_mkfifo.U:
2581
2582           This variable conditionally defines the "HAS_MKFIFO" symbol, which
2583           indicates to the C program that the mkfifo() routine is available.
2584
2585       "d_mkstemp"
2586           From d_mkstemp.U:
2587
2588           This variable conditionally defines the "HAS_MKSTEMP" symbol, which
2589           indicates to the C program that the mkstemp() routine is available
2590           to exclusively create and open a uniquely named temporary file.
2591
2592       "d_mkstemps"
2593           From d_mkstemps.U:
2594
2595           This variable conditionally defines the "HAS_MKSTEMPS" symbol,
2596           which indicates to the C program that the mkstemps() routine is
2597           available to exclusively create and open a uniquely named (with a
2598           suffix) temporary file.
2599
2600       "d_mktime"
2601           From d_mktime.U:
2602
2603           This variable conditionally defines the "HAS_MKTIME" symbol, which
2604           indicates to the C program that the mktime() routine is available.
2605
2606       "d_mktime64"
2607           From d_timefuncs64.U:
2608
2609           This variable conditionally defines the HAS_MKTIME64 symbol, which
2610           indicates to the C program that the mktime64 () routine is
2611           available.
2612
2613       "d_mmap"
2614           From d_mmap.U:
2615
2616           This variable conditionally defines "HAS_MMAP" if mmap() is
2617           available to map a file into memory.
2618
2619       "d_modfl"
2620           From d_modfl.U:
2621
2622           This variable conditionally defines the "HAS_MODFL" symbol, which
2623           indicates to the C program that the modfl() routine is available.
2624
2625       "d_modflproto"
2626           From d_modfl.U:
2627
2628           This symbol, if defined, indicates that the system provides a
2629           prototype for the modfl() function.  Otherwise, it is up to the
2630           program to supply one.  C99 says it should be long double
2631           modfl(long double, long double *);
2632
2633       "d_mprotect"
2634           From d_mprotect.U:
2635
2636           This variable conditionally defines "HAS_MPROTECT" if mprotect() is
2637           available to modify the access protection of a memory mapped file.
2638
2639       "d_msg"
2640           From d_msg.U:
2641
2642           This variable conditionally defines the "HAS_MSG" symbol, which
2643           indicates that the entire msg*(2) library is present.
2644
2645       "d_msg_ctrunc"
2646           From d_socket.U:
2647
2648           This variable conditionally defines the "HAS_MSG_CTRUNC" symbol,
2649           which indicates that the "MSG_CTRUNC" is available.  #ifdef is not
2650           enough because it may be an enum, glibc has been known to do this.
2651
2652       "d_msg_dontroute"
2653           From d_socket.U:
2654
2655           This variable conditionally defines the "HAS_MSG_DONTROUTE" symbol,
2656           which indicates that the "MSG_DONTROUTE" is available.  #ifdef is
2657           not enough because it may be an enum, glibc has been known to do
2658           this.
2659
2660       "d_msg_oob"
2661           From d_socket.U:
2662
2663           This variable conditionally defines the "HAS_MSG_OOB" symbol, which
2664           indicates that the "MSG_OOB" is available.  #ifdef is not enough
2665           because it may be an enum, glibc has been known to do this.
2666
2667       "d_msg_peek"
2668           From d_socket.U:
2669
2670           This variable conditionally defines the "HAS_MSG_PEEK" symbol,
2671           which indicates that the "MSG_PEEK" is available.  #ifdef is not
2672           enough because it may be an enum, glibc has been known to do this.
2673
2674       "d_msg_proxy"
2675           From d_socket.U:
2676
2677           This variable conditionally defines the "HAS_MSG_PROXY" symbol,
2678           which indicates that the "MSG_PROXY" is available.  #ifdef is not
2679           enough because it may be an enum, glibc has been known to do this.
2680
2681       "d_msgctl"
2682           From d_msgctl.U:
2683
2684           This variable conditionally defines the "HAS_MSGCTL" symbol, which
2685           indicates to the C program that the msgctl() routine is available.
2686
2687       "d_msgget"
2688           From d_msgget.U:
2689
2690           This variable conditionally defines the "HAS_MSGGET" symbol, which
2691           indicates to the C program that the msgget() routine is available.
2692
2693       "d_msghdr_s"
2694           From d_msghdr_s.U:
2695
2696           This variable conditionally defines the "HAS_STRUCT_MSGHDR" symbol,
2697           which indicates that the struct msghdr is supported.
2698
2699       "d_msgrcv"
2700           From d_msgrcv.U:
2701
2702           This variable conditionally defines the "HAS_MSGRCV" symbol, which
2703           indicates to the C program that the msgrcv() routine is available.
2704
2705       "d_msgsnd"
2706           From d_msgsnd.U:
2707
2708           This variable conditionally defines the "HAS_MSGSND" symbol, which
2709           indicates to the C program that the msgsnd() routine is available.
2710
2711       "d_msync"
2712           From d_msync.U:
2713
2714           This variable conditionally defines "HAS_MSYNC" if msync() is
2715           available to synchronize a mapped file.
2716
2717       "d_munmap"
2718           From d_munmap.U:
2719
2720           This variable conditionally defines "HAS_MUNMAP" if munmap() is
2721           available to unmap a region mapped by mmap().
2722
2723       "d_mymalloc"
2724           From mallocsrc.U:
2725
2726           This variable conditionally defines "MYMALLOC" in case other parts
2727           of the source want to take special action if "MYMALLOC" is used.
2728           This may include different sorts of profiling or error detection.
2729
2730       "d_nan"
2731           From d_nan.U:
2732
2733           This variable conditionally defines "HAS_NAN" if nan() is available
2734           to generate NaN.
2735
2736       "d_ndbm"
2737           From i_ndbm.U:
2738
2739           This variable conditionally defines the "HAS_NDBM" symbol, which
2740           indicates that both the ndbm.h include file and an appropriate ndbm
2741           library exist.  Consult the different i_*ndbm variables to find out
2742           the actual include location.  Sometimes, a system has the header
2743           file but not the library.  This variable will only be set if the
2744           system has both.
2745
2746       "d_ndbm_h_uses_prototypes"
2747           From i_ndbm.U:
2748
2749           This variable conditionally defines the "NDBM_H_USES_PROTOTYPES"
2750           symbol, which indicates that the ndbm.h include file uses real
2751           "ANSI" C prototypes instead of K&R style function declarations. K&R
2752           style declarations are unsupported in C++, so the include file
2753           requires special handling when using a C++ compiler and this
2754           variable is undefined. Consult the different
2755           d_*ndbm_h_uses_prototypes variables to get the same information for
2756           alternative ndbm.h include files.
2757
2758       "d_nearbyint"
2759           From d_nearbyint.U:
2760
2761           This variable conditionally defines "HAS_NEARBYINT" if nearbyint()
2762           is available to return the integral value closest to (according to
2763           the current rounding mode) to x.
2764
2765       "d_newlocale"
2766           From d_newlocale.U:
2767
2768           This variable conditionally defines the "HAS_NEWLOCALE" symbol,
2769           which indicates to the C program that the newlocale() routine is
2770           available to return a new locale object or modify an existing
2771           locale object.
2772
2773       "d_nextafter"
2774           From d_nextafter.U:
2775
2776           This variable conditionally defines "HAS_NEXTAFTER" if nextafter()
2777           is available to return the next machine representable double from x
2778           in direction y.
2779
2780       "d_nexttoward"
2781           From d_nexttoward.U:
2782
2783           This variable conditionally defines "HAS_NEXTTOWARD" if
2784           nexttoward() is available to return the next machine representable
2785           long double from x in direction y.
2786
2787       "d_nice"
2788           From d_nice.U:
2789
2790           This variable conditionally defines the "HAS_NICE" symbol, which
2791           indicates to the C program that the nice() routine is available.
2792
2793       "d_nl_langinfo"
2794           From d_nl_langinfo.U:
2795
2796           This variable conditionally defines the "HAS_NL_LANGINFO" symbol,
2797           which indicates to the C program that the nl_langinfo() routine is
2798           available.
2799
2800       "d_nv_preserves_uv"
2801           From perlxv.U:
2802
2803           This variable indicates whether a variable of type nvtype can
2804           preserve all the bits a variable of type uvtype.
2805
2806       "d_nv_zero_is_allbits_zero"
2807           From perlxv.U:
2808
2809           This variable indicates whether a variable of type nvtype stores
2810           0.0 in memory as all bits zero.
2811
2812       "d_off64_t"
2813           From d_off64_t.U:
2814
2815           This symbol will be defined if the C compiler supports off64_t.
2816
2817       "d_old_pthread_create_joinable"
2818           From d_pthrattrj.U:
2819
2820           This variable conditionally defines pthread_create_joinable.  undef
2821           if pthread.h defines "PTHREAD_CREATE_JOINABLE".
2822
2823       "d_oldpthreads"
2824           From usethreads.U:
2825
2826           This variable conditionally defines the "OLD_PTHREADS_API" symbol,
2827           and indicates that Perl should be built to use the old draft
2828           "POSIX" threads "API".  This is only potentially meaningful if
2829           usethreads is set.
2830
2831       "d_oldsock"
2832           From d_socket.U:
2833
2834           This variable conditionally defines the "OLDSOCKET" symbol, which
2835           indicates that the "BSD" socket interface is based on 4.1c and not
2836           4.2.
2837
2838       "d_open3"
2839           From d_open3.U:
2840
2841           This variable conditionally defines the HAS_OPEN3 manifest
2842           constant, which indicates to the C program that the 3 argument
2843           version of the open(2) function is available.
2844
2845       "d_pathconf"
2846           From d_pathconf.U:
2847
2848           This variable conditionally defines the "HAS_PATHCONF" symbol,
2849           which indicates to the C program that the pathconf() routine is
2850           available to determine file-system related limits and options
2851           associated with a given filename.
2852
2853       "d_pause"
2854           From d_pause.U:
2855
2856           This variable conditionally defines the "HAS_PAUSE" symbol, which
2857           indicates to the C program that the pause() routine is available to
2858           suspend a process until a signal is received.
2859
2860       "d_perl_otherlibdirs"
2861           From otherlibdirs.U:
2862
2863           This variable conditionally defines "PERL_OTHERLIBDIRS", which
2864           contains a colon-separated set of paths for the perl binary to
2865           include in @"INC".  See also otherlibdirs.
2866
2867       "d_phostname"
2868           From d_gethname.U:
2869
2870           This variable conditionally defines the "HAS_PHOSTNAME" symbol,
2871           which contains the shell command which, when fed to popen(), may be
2872           used to derive the host name.
2873
2874       "d_pipe"
2875           From d_pipe.U:
2876
2877           This variable conditionally defines the "HAS_PIPE" symbol, which
2878           indicates to the C program that the pipe() routine is available to
2879           create an inter-process channel.
2880
2881       "d_poll"
2882           From d_poll.U:
2883
2884           This variable conditionally defines the "HAS_POLL" symbol, which
2885           indicates to the C program that the poll() routine is available to
2886           poll active file descriptors.
2887
2888       "d_portable"
2889           From d_portable.U:
2890
2891           This variable conditionally defines the "PORTABLE" symbol, which
2892           indicates to the C program that it should not assume that it is
2893           running on the machine it was compiled on.
2894
2895       "d_prctl"
2896           From d_prctl.U:
2897
2898           This variable conditionally defines the "HAS_PRCTL" symbol, which
2899           indicates to the C program that the prctl() routine is available.
2900           Note that there are at least two prctl variants: Linux and Irix.
2901           While they are somewhat similar, they are incompatible.
2902
2903       "d_prctl_set_name"
2904           From d_prctl.U:
2905
2906           This variable conditionally defines the "HAS_PRCTL_SET_NAME"
2907           symbol, which indicates to the C program that the prctl() routine
2908           supports the "PR_SET_NAME" option.
2909
2910       "d_PRId64"
2911           From quadfio.U:
2912
2913           This variable conditionally defines the PERL_PRId64 symbol, which
2914           indicates that stdio has a symbol to print 64-bit decimal numbers.
2915
2916       "d_PRIeldbl"
2917           From longdblfio.U:
2918
2919           This variable conditionally defines the PERL_PRIfldbl symbol, which
2920           indicates that stdio has a symbol to print long doubles.
2921
2922       "d_PRIEUldbl"
2923           From longdblfio.U:
2924
2925           This variable conditionally defines the PERL_PRIfldbl symbol, which
2926           indicates that stdio has a symbol to print long doubles.  The "U"
2927           in the name is to separate this from d_PRIeldbl so that even case-
2928           blind systems can see the difference.
2929
2930       "d_PRIfldbl"
2931           From longdblfio.U:
2932
2933           This variable conditionally defines the PERL_PRIfldbl symbol, which
2934           indicates that stdio has a symbol to print long doubles.
2935
2936       "d_PRIFUldbl"
2937           From longdblfio.U:
2938
2939           This variable conditionally defines the PERL_PRIfldbl symbol, which
2940           indicates that stdio has a symbol to print long doubles.  The "U"
2941           in the name is to separate this from d_PRIfldbl so that even case-
2942           blind systems can see the difference.
2943
2944       "d_PRIgldbl"
2945           From longdblfio.U:
2946
2947           This variable conditionally defines the PERL_PRIfldbl symbol, which
2948           indicates that stdio has a symbol to print long doubles.
2949
2950       "d_PRIGUldbl"
2951           From longdblfio.U:
2952
2953           This variable conditionally defines the PERL_PRIfldbl symbol, which
2954           indicates that stdio has a symbol to print long doubles.  The "U"
2955           in the name is to separate this from d_PRIgldbl so that even case-
2956           blind systems can see the difference.
2957
2958       "d_PRIi64"
2959           From quadfio.U:
2960
2961           This variable conditionally defines the PERL_PRIi64 symbol, which
2962           indicates that stdio has a symbol to print 64-bit decimal numbers.
2963
2964       "d_printf_format_null"
2965           From d_attribut.U:
2966
2967           This variable conditionally defines "PRINTF_FORMAT_NULL_OK", which
2968           indicates the C compiler allows printf-like formats to be null.
2969
2970       "d_PRIo64"
2971           From quadfio.U:
2972
2973           This variable conditionally defines the PERL_PRIo64 symbol, which
2974           indicates that stdio has a symbol to print 64-bit octal numbers.
2975
2976       "d_PRIu64"
2977           From quadfio.U:
2978
2979           This variable conditionally defines the PERL_PRIu64 symbol, which
2980           indicates that stdio has a symbol to print 64-bit unsigned decimal
2981           numbers.
2982
2983       "d_PRIx64"
2984           From quadfio.U:
2985
2986           This variable conditionally defines the PERL_PRIx64 symbol, which
2987           indicates that stdio has a symbol to print 64-bit hexadecimal
2988           numbers.
2989
2990       "d_PRIXU64"
2991           From quadfio.U:
2992
2993           This variable conditionally defines the PERL_PRIXU64 symbol, which
2994           indicates that stdio has a symbol to print 64-bit hExADECimAl
2995           numbers.  The "U" in the name is to separate this from d_PRIx64 so
2996           that even case-blind systems can see the difference.
2997
2998       "d_procselfexe"
2999           From d_procselfexe.U:
3000
3001           Defined if $procselfexe is symlink to the absolute pathname of the
3002           executing program.
3003
3004       "d_pseudofork"
3005           From d_vfork.U:
3006
3007           This variable conditionally defines the "HAS_PSEUDOFORK" symbol,
3008           which indicates that an emulation of the fork routine is available.
3009
3010       "d_pthread_atfork"
3011           From d_pthread_atfork.U:
3012
3013           This variable conditionally defines the "HAS_PTHREAD_ATFORK"
3014           symbol, which indicates to the C program that the pthread_atfork()
3015           routine is available.
3016
3017       "d_pthread_attr_setscope"
3018           From d_pthread_attr_ss.U:
3019
3020           This variable conditionally defines "HAS_PTHREAD_ATTR_SETSCOPE" if
3021           pthread_attr_setscope() is available to set the contention scope
3022           attribute of a thread attribute object.
3023
3024       "d_pthread_yield"
3025           From d_pthread_y.U:
3026
3027           This variable conditionally defines the "HAS_PTHREAD_YIELD" symbol
3028           if the pthread_yield routine is available to yield the execution of
3029           the current thread.
3030
3031       "d_ptrdiff_t"
3032           From d_ptrdiff_t.U:
3033
3034           This symbol will be defined if the C compiler supports ptrdiff_t.
3035
3036       "d_pwage"
3037           From i_pwd.U:
3038
3039           This variable conditionally defines "PWAGE", which indicates that
3040           struct passwd contains pw_age.
3041
3042       "d_pwchange"
3043           From i_pwd.U:
3044
3045           This variable conditionally defines "PWCHANGE", which indicates
3046           that struct passwd contains pw_change.
3047
3048       "d_pwclass"
3049           From i_pwd.U:
3050
3051           This variable conditionally defines "PWCLASS", which indicates that
3052           struct passwd contains pw_class.
3053
3054       "d_pwcomment"
3055           From i_pwd.U:
3056
3057           This variable conditionally defines "PWCOMMENT", which indicates
3058           that struct passwd contains pw_comment.
3059
3060       "d_pwexpire"
3061           From i_pwd.U:
3062
3063           This variable conditionally defines "PWEXPIRE", which indicates
3064           that struct passwd contains pw_expire.
3065
3066       "d_pwgecos"
3067           From i_pwd.U:
3068
3069           This variable conditionally defines "PWGECOS", which indicates that
3070           struct passwd contains pw_gecos.
3071
3072       "d_pwpasswd"
3073           From i_pwd.U:
3074
3075           This variable conditionally defines "PWPASSWD", which indicates
3076           that struct passwd contains pw_passwd.
3077
3078       "d_pwquota"
3079           From i_pwd.U:
3080
3081           This variable conditionally defines "PWQUOTA", which indicates that
3082           struct passwd contains pw_quota.
3083
3084       "d_qgcvt"
3085           From d_qgcvt.U:
3086
3087           This variable conditionally defines the "HAS_QGCVT" symbol, which
3088           indicates to the C program that the qgcvt() routine is available.
3089
3090       "d_quad"
3091           From quadtype.U:
3092
3093           This variable, if defined, tells that there's a 64-bit integer
3094           type, quadtype.
3095
3096       "d_querylocale"
3097           From d_newlocale.U:
3098
3099           This variable conditionally defines the "HAS_QUERYLOCALE" symbol,
3100           which indicates to the C program that the querylocale() routine is
3101           available to return the name of the locale for a category mask.
3102
3103       "d_random_r"
3104           From d_random_r.U:
3105
3106           This variable conditionally defines the "HAS_RANDOM_R" symbol,
3107           which indicates to the C program that the random_r() routine is
3108           available.
3109
3110       "d_re_comp"
3111           From d_regcmp.U:
3112
3113           This variable conditionally defines the "HAS_RECOMP" symbol, which
3114           indicates to the C program that the re_comp() routine is available
3115           for regular patern matching (usally on "BSD"). If so, it is likely
3116           that re_exec() exists.
3117
3118       "d_readdir"
3119           From d_readdir.U:
3120
3121           This variable conditionally defines "HAS_READDIR" if readdir() is
3122           available to read directory entries.
3123
3124       "d_readdir64_r"
3125           From d_readdir64_r.U:
3126
3127           This variable conditionally defines the HAS_READDIR64_R symbol,
3128           which indicates to the C program that the readdir64_r() routine is
3129           available.
3130
3131       "d_readdir_r"
3132           From d_readdir_r.U:
3133
3134           This variable conditionally defines the "HAS_READDIR_R" symbol,
3135           which indicates to the C program that the readdir_r() routine is
3136           available.
3137
3138       "d_readlink"
3139           From d_readlink.U:
3140
3141           This variable conditionally defines the "HAS_READLINK" symbol,
3142           which indicates to the C program that the readlink() routine is
3143           available to read the value of a symbolic link.
3144
3145       "d_readv"
3146           From d_readv.U:
3147
3148           This variable conditionally defines the "HAS_READV" symbol, which
3149           indicates to the C program that the readv() routine is available.
3150
3151       "d_recvmsg"
3152           From d_recvmsg.U:
3153
3154           This variable conditionally defines the "HAS_RECVMSG" symbol, which
3155           indicates to the C program that the recvmsg() routine is available.
3156
3157       "d_regcmp"
3158           From d_regcmp.U:
3159
3160           This variable conditionally defines the "HAS_REGCMP" symbol, which
3161           indicates to the C program that the regcmp() routine is available
3162           for regular patern matching (usally on System V).
3163
3164       "d_regcomp"
3165           From d_regcmp.U:
3166
3167           This variable conditionally defines the "HAS_REGCOMP" symbol, which
3168           indicates to the C program that the regcomp() routine is available
3169           for regular patern matching (usally on POSIX.2 conforming systems).
3170
3171       "d_remainder"
3172           From d_remainder.U:
3173
3174           This variable conditionally defines the "HAS_REMAINDER" symbol,
3175           which indicates to the C program that the remainder() routine is
3176           available.
3177
3178       "d_remquo"
3179           From d_remquo.U:
3180
3181           This variable conditionally defines the "HAS_REMQUO" symbol, which
3182           indicates to the C program that the remquo() routine is available.
3183
3184       "d_rename"
3185           From d_rename.U:
3186
3187           This variable conditionally defines the "HAS_RENAME" symbol, which
3188           indicates to the C program that the rename() routine is available
3189           to rename files.
3190
3191       "d_rewinddir"
3192           From d_readdir.U:
3193
3194           This variable conditionally defines "HAS_REWINDDIR" if rewinddir()
3195           is available.
3196
3197       "d_rint"
3198           From d_rint.U:
3199
3200           This variable conditionally defines the "HAS_RINT" symbol, which
3201           indicates to the C program that the rint() routine is available.
3202
3203       "d_rmdir"
3204           From d_rmdir.U:
3205
3206           This variable conditionally defines "HAS_RMDIR" if rmdir() is
3207           available to remove directories.
3208
3209       "d_round"
3210           From d_round.U:
3211
3212           This variable conditionally defines the "HAS_ROUND" symbol, which
3213           indicates to the C program that the round() routine is available.
3214
3215       "d_safebcpy"
3216           From d_safebcpy.U:
3217
3218           This variable conditionally defines the "HAS_SAFE_BCOPY" symbol if
3219           the bcopy() routine can do overlapping copies.  Normally, you
3220           should probably use memmove().
3221
3222       "d_safemcpy"
3223           From d_safemcpy.U:
3224
3225           This variable conditionally defines the "HAS_SAFE_MEMCPY" symbol if
3226           the memcpy() routine can do overlapping copies.  For overlapping
3227           copies, memmove() should be used, if available.
3228
3229       "d_sanemcmp"
3230           From d_sanemcmp.U:
3231
3232           This variable conditionally defines the "HAS_SANE_MEMCMP" symbol if
3233           the memcpy() routine is available and can be used to compare
3234           relative magnitudes of chars with their high bits set.
3235
3236       "d_sbrkproto"
3237           From d_sbrkproto.U:
3238
3239           This variable conditionally defines the "HAS_SBRK_PROTO" symbol,
3240           which indicates to the C program that the system provides a
3241           prototype for the sbrk() function.  Otherwise, it is up to the
3242           program to supply one.
3243
3244       "d_scalbn"
3245           From d_scalbn.U:
3246
3247           This variable conditionally defines the "HAS_SCALBN" symbol, which
3248           indicates to the C program that the scalbn() routine is available.
3249
3250       "d_scalbnl"
3251           From d_scalbnl.U:
3252
3253           This variable conditionally defines the "HAS_SCALBNL" symbol, which
3254           indicates to the C program that the scalbnl() routine is available.
3255           If ilogbl is also present we can emulate frexpl.
3256
3257       "d_sched_yield"
3258           From d_pthread_y.U:
3259
3260           This variable conditionally defines the "HAS_SCHED_YIELD" symbol if
3261           the sched_yield routine is available to yield the execution of the
3262           current thread.
3263
3264       "d_scm_rights"
3265           From d_socket.U:
3266
3267           This variable conditionally defines the "HAS_SCM_RIGHTS" symbol,
3268           which indicates that the "SCM_RIGHTS" is available.  #ifdef is not
3269           enough because it may be an enum, glibc has been known to do this.
3270
3271       "d_SCNfldbl"
3272           From longdblfio.U:
3273
3274           This variable conditionally defines the PERL_PRIfldbl symbol, which
3275           indicates that stdio has a symbol to scan long doubles.
3276
3277       "d_seekdir"
3278           From d_readdir.U:
3279
3280           This variable conditionally defines "HAS_SEEKDIR" if seekdir() is
3281           available.
3282
3283       "d_select"
3284           From d_select.U:
3285
3286           This variable conditionally defines "HAS_SELECT" if select() is
3287           available to select active file descriptors. A <sys/time.h>
3288           inclusion may be necessary for the timeout field.
3289
3290       "d_sem"
3291           From d_sem.U:
3292
3293           This variable conditionally defines the "HAS_SEM" symbol, which
3294           indicates that the entire sem*(2) library is present.
3295
3296       "d_semctl"
3297           From d_semctl.U:
3298
3299           This variable conditionally defines the "HAS_SEMCTL" symbol, which
3300           indicates to the C program that the semctl() routine is available.
3301
3302       "d_semctl_semid_ds"
3303           From d_union_semun.U:
3304
3305           This variable conditionally defines "USE_SEMCTL_SEMID_DS", which
3306           indicates that struct semid_ds * is to be used for semctl
3307           "IPC_STAT".
3308
3309       "d_semctl_semun"
3310           From d_union_semun.U:
3311
3312           This variable conditionally defines "USE_SEMCTL_SEMUN", which
3313           indicates that union semun is to be used for semctl "IPC_STAT".
3314
3315       "d_semget"
3316           From d_semget.U:
3317
3318           This variable conditionally defines the "HAS_SEMGET" symbol, which
3319           indicates to the C program that the semget() routine is available.
3320
3321       "d_semop"
3322           From d_semop.U:
3323
3324           This variable conditionally defines the "HAS_SEMOP" symbol, which
3325           indicates to the C program that the semop() routine is available.
3326
3327       "d_sendmsg"
3328           From d_sendmsg.U:
3329
3330           This variable conditionally defines the "HAS_SENDMSG" symbol, which
3331           indicates to the C program that the sendmsg() routine is available.
3332
3333       "d_setegid"
3334           From d_setegid.U:
3335
3336           This variable conditionally defines the "HAS_SETEGID" symbol, which
3337           indicates to the C program that the setegid() routine is available
3338           to change the effective gid of the current program.
3339
3340       "d_seteuid"
3341           From d_seteuid.U:
3342
3343           This variable conditionally defines the "HAS_SETEUID" symbol, which
3344           indicates to the C program that the seteuid() routine is available
3345           to change the effective uid of the current program.
3346
3347       "d_setgrent"
3348           From d_setgrent.U:
3349
3350           This variable conditionally defines the "HAS_SETGRENT" symbol,
3351           which indicates to the C program that the setgrent() routine is
3352           available for initializing sequential access to the group database.
3353
3354       "d_setgrent_r"
3355           From d_setgrent_r.U:
3356
3357           This variable conditionally defines the "HAS_SETGRENT_R" symbol,
3358           which indicates to the C program that the setgrent_r() routine is
3359           available.
3360
3361       "d_setgrps"
3362           From d_setgrps.U:
3363
3364           This variable conditionally defines the "HAS_SETGROUPS" symbol,
3365           which indicates to the C program that the setgroups() routine is
3366           available to set the list of process groups.
3367
3368       "d_sethent"
3369           From d_sethent.U:
3370
3371           This variable conditionally defines "HAS_SETHOSTENT" if
3372           sethostent() is available.
3373
3374       "d_sethostent_r"
3375           From d_sethostent_r.U:
3376
3377           This variable conditionally defines the "HAS_SETHOSTENT_R" symbol,
3378           which indicates to the C program that the sethostent_r() routine is
3379           available.
3380
3381       "d_setitimer"
3382           From d_setitimer.U:
3383
3384           This variable conditionally defines the "HAS_SETITIMER" symbol,
3385           which indicates to the C program that the setitimer() routine is
3386           available.
3387
3388       "d_setlinebuf"
3389           From d_setlnbuf.U:
3390
3391           This variable conditionally defines the "HAS_SETLINEBUF" symbol,
3392           which indicates to the C program that the setlinebuf() routine is
3393           available to change stderr or stdout from block-buffered or
3394           unbuffered to a line-buffered mode.
3395
3396       "d_setlocale"
3397           From d_setlocale.U:
3398
3399           This variable conditionally defines "HAS_SETLOCALE" if setlocale()
3400           is available to handle locale-specific ctype implementations.
3401
3402       "d_setlocale_r"
3403           From d_setlocale_r.U:
3404
3405           This variable conditionally defines the "HAS_SETLOCALE_R" symbol,
3406           which indicates to the C program that the setlocale_r() routine is
3407           available.
3408
3409       "d_setnent"
3410           From d_setnent.U:
3411
3412           This variable conditionally defines "HAS_SETNETENT" if setnetent()
3413           is available.
3414
3415       "d_setnetent_r"
3416           From d_setnetent_r.U:
3417
3418           This variable conditionally defines the "HAS_SETNETENT_R" symbol,
3419           which indicates to the C program that the setnetent_r() routine is
3420           available.
3421
3422       "d_setpent"
3423           From d_setpent.U:
3424
3425           This variable conditionally defines "HAS_SETPROTOENT" if
3426           setprotoent() is available.
3427
3428       "d_setpgid"
3429           From d_setpgid.U:
3430
3431           This variable conditionally defines the "HAS_SETPGID" symbol if the
3432           setpgid(pid, gpid) function is available to set process group "ID".
3433
3434       "d_setpgrp"
3435           From d_setpgrp.U:
3436
3437           This variable conditionally defines "HAS_SETPGRP" if setpgrp() is
3438           available to set the current process group.
3439
3440       "d_setpgrp2"
3441           From d_setpgrp2.U:
3442
3443           This variable conditionally defines the HAS_SETPGRP2 symbol, which
3444           indicates to the C program that the setpgrp2() (as in DG/"UX")
3445           routine is available to set the current process group.
3446
3447       "d_setprior"
3448           From d_setprior.U:
3449
3450           This variable conditionally defines "HAS_SETPRIORITY" if
3451           setpriority() is available to set a process's priority.
3452
3453       "d_setproctitle"
3454           From d_setproctitle.U:
3455
3456           This variable conditionally defines the "HAS_SETPROCTITLE" symbol,
3457           which indicates to the C program that the setproctitle() routine is
3458           available.
3459
3460       "d_setprotoent_r"
3461           From d_setprotoent_r.U:
3462
3463           This variable conditionally defines the "HAS_SETPROTOENT_R" symbol,
3464           which indicates to the C program that the setprotoent_r() routine
3465           is available.
3466
3467       "d_setpwent"
3468           From d_setpwent.U:
3469
3470           This variable conditionally defines the "HAS_SETPWENT" symbol,
3471           which indicates to the C program that the setpwent() routine is
3472           available for initializing sequential access to the passwd
3473           database.
3474
3475       "d_setpwent_r"
3476           From d_setpwent_r.U:
3477
3478           This variable conditionally defines the "HAS_SETPWENT_R" symbol,
3479           which indicates to the C program that the setpwent_r() routine is
3480           available.
3481
3482       "d_setregid"
3483           From d_setregid.U:
3484
3485           This variable conditionally defines "HAS_SETREGID" if setregid() is
3486           available to change the real and effective gid of the current
3487           process.
3488
3489       "d_setresgid"
3490           From d_setregid.U:
3491
3492           This variable conditionally defines "HAS_SETRESGID" if setresgid()
3493           is available to change the real, effective and saved gid of the
3494           current process.
3495
3496       "d_setresuid"
3497           From d_setreuid.U:
3498
3499           This variable conditionally defines "HAS_SETREUID" if setresuid()
3500           is available to change the real, effective and saved uid of the
3501           current process.
3502
3503       "d_setreuid"
3504           From d_setreuid.U:
3505
3506           This variable conditionally defines "HAS_SETREUID" if setreuid() is
3507           available to change the real and effective uid of the current
3508           process.
3509
3510       "d_setrgid"
3511           From d_setrgid.U:
3512
3513           This variable conditionally defines the "HAS_SETRGID" symbol, which
3514           indicates to the C program that the setrgid() routine is available
3515           to change the real gid of the current program.
3516
3517       "d_setruid"
3518           From d_setruid.U:
3519
3520           This variable conditionally defines the "HAS_SETRUID" symbol, which
3521           indicates to the C program that the setruid() routine is available
3522           to change the real uid of the current program.
3523
3524       "d_setsent"
3525           From d_setsent.U:
3526
3527           This variable conditionally defines "HAS_SETSERVENT" if
3528           setservent() is available.
3529
3530       "d_setservent_r"
3531           From d_setservent_r.U:
3532
3533           This variable conditionally defines the "HAS_SETSERVENT_R" symbol,
3534           which indicates to the C program that the setservent_r() routine is
3535           available.
3536
3537       "d_setsid"
3538           From d_setsid.U:
3539
3540           This variable conditionally defines "HAS_SETSID" if setsid() is
3541           available to set the process group "ID".
3542
3543       "d_setvbuf"
3544           From d_setvbuf.U:
3545
3546           This variable conditionally defines the "HAS_SETVBUF" symbol, which
3547           indicates to the C program that the setvbuf() routine is available
3548           to change buffering on an open stdio stream.
3549
3550       "d_shm"
3551           From d_shm.U:
3552
3553           This variable conditionally defines the "HAS_SHM" symbol, which
3554           indicates that the entire shm*(2) library is present.
3555
3556       "d_shmat"
3557           From d_shmat.U:
3558
3559           This variable conditionally defines the "HAS_SHMAT" symbol, which
3560           indicates to the C program that the shmat() routine is available.
3561
3562       "d_shmatprototype"
3563           From d_shmat.U:
3564
3565           This variable conditionally defines the "HAS_SHMAT_PROTOTYPE"
3566           symbol, which indicates that sys/shm.h has a prototype for shmat.
3567
3568       "d_shmctl"
3569           From d_shmctl.U:
3570
3571           This variable conditionally defines the "HAS_SHMCTL" symbol, which
3572           indicates to the C program that the shmctl() routine is available.
3573
3574       "d_shmdt"
3575           From d_shmdt.U:
3576
3577           This variable conditionally defines the "HAS_SHMDT" symbol, which
3578           indicates to the C program that the shmdt() routine is available.
3579
3580       "d_shmget"
3581           From d_shmget.U:
3582
3583           This variable conditionally defines the "HAS_SHMGET" symbol, which
3584           indicates to the C program that the shmget() routine is available.
3585
3586       "d_sigaction"
3587           From d_sigaction.U:
3588
3589           This variable conditionally defines the "HAS_SIGACTION" symbol,
3590           which indicates that the Vr4 sigaction() routine is available.
3591
3592       "d_siginfo_si_addr"
3593           From d_siginfo_si.U:
3594
3595           This variable conditionally defines the "HAS_SIGINFO_SI_ADDR"
3596           symbol, which indicates that the siginfo_t struct has the si_addr
3597           member.
3598
3599       "d_siginfo_si_band"
3600           From d_siginfo_si.U:
3601
3602           This variable conditionally defines the "HAS_SIGINFO_SI_BAND"
3603           symbol, which indicates that the siginfo_t struct has the si_band
3604           member.
3605
3606       "d_siginfo_si_errno"
3607           From d_siginfo_si.U:
3608
3609           This variable conditionally defines the "HAS_SIGINFO_SI_ERRNO"
3610           symbol, which indicates that the siginfo_t struct has the si_errno
3611           member.
3612
3613       "d_siginfo_si_fd"
3614           From d_siginfo_si.U:
3615
3616           This variable conditionally defines the "HAS_SIGINFO_SI_FD" symbol,
3617           which indicates that the siginfo_t struct has the si_fd member.
3618
3619       "d_siginfo_si_pid"
3620           From d_siginfo_si.U:
3621
3622           This variable conditionally defines the "HAS_SIGINFO_SI_PID"
3623           symbol, which indicates that the siginfo_t struct has the si_pid
3624           member.
3625
3626       "d_siginfo_si_status"
3627           From d_siginfo_si.U:
3628
3629           This variable conditionally defines the "HAS_SIGINFO_SI_STATUS"
3630           symbol, which indicates that the siginfo_t struct has the si_status
3631           member.
3632
3633       "d_siginfo_si_uid"
3634           From d_siginfo_si.U:
3635
3636           This variable conditionally defines the "HAS_SIGINFO_SI_UID"
3637           symbol, which indicates that the siginfo_t struct has the si_uid
3638           member.
3639
3640       "d_siginfo_si_value"
3641           From d_siginfo_si.U:
3642
3643           This variable conditionally defines the "HAS_SIGINFO_SI_VALUE"
3644           symbol, which indicates that the siginfo_t struct has the si_value
3645           member.
3646
3647       "d_signbit"
3648           From d_signbit.U:
3649
3650           This variable conditionally defines the "HAS_SIGNBIT" symbol, which
3651           indicates to the C program that the signbit() routine is available
3652           and safe to use with perl's intern "NV" type.
3653
3654       "d_sigprocmask"
3655           From d_sigprocmask.U:
3656
3657           This variable conditionally defines "HAS_SIGPROCMASK" if
3658           sigprocmask() is available to examine or change the signal mask of
3659           the calling process.
3660
3661       "d_sigsetjmp"
3662           From d_sigsetjmp.U:
3663
3664           This variable conditionally defines the "HAS_SIGSETJMP" symbol,
3665           which indicates that the sigsetjmp() routine is available to call
3666           setjmp() and optionally save the process's signal mask.
3667
3668       "d_sin6_scope_id"
3669           From d_socket.U:
3670
3671           This variable conditionally defines the HAS_SIN6_SCOPE_ID symbol,
3672           which indicates that a struct sockaddr_in6 structure has the
3673           sin6_scope_id member.
3674
3675       "d_sitearch"
3676           From sitearch.U:
3677
3678           This variable conditionally defines "SITEARCH" to hold the pathname
3679           of architecture-dependent library files for $package.  If $sitearch
3680           is the same as $archlib, then this is set to undef.
3681
3682       "d_snprintf"
3683           From d_snprintf.U:
3684
3685           This variable conditionally defines the "HAS_SNPRINTF" symbol,
3686           which indicates to the C program that the snprintf () library
3687           function is available.
3688
3689       "d_sockaddr_in6"
3690           From d_socket.U:
3691
3692           This variable conditionally defines the HAS_SOCKADDR_IN6 symbol,
3693           which indicates the availability of a struct sockaddr_in6.
3694
3695       "d_sockaddr_sa_len"
3696           From d_socket.U:
3697
3698           This variable conditionally defines the "HAS_SOCKADDR_SA_LEN"
3699           symbol, which indicates that a struct sockaddr structure has the
3700           sa_len member.
3701
3702       "d_sockatmark"
3703           From d_sockatmark.U:
3704
3705           This variable conditionally defines the "HAS_SOCKATMARK" symbol,
3706           which indicates to the C program that the sockatmark() routine is
3707           available.
3708
3709       "d_sockatmarkproto"
3710           From d_sockatmarkproto.U:
3711
3712           This variable conditionally defines the "HAS_SOCKATMARK_PROTO"
3713           symbol, which indicates to the C program that the system provides a
3714           prototype for the sockatmark() function.  Otherwise, it is up to
3715           the program to supply one.
3716
3717       "d_socket"
3718           From d_socket.U:
3719
3720           This variable conditionally defines "HAS_SOCKET", which indicates
3721           that the "BSD" socket interface is supported.
3722
3723       "d_socklen_t"
3724           From d_socklen_t.U:
3725
3726           This symbol will be defined if the C compiler supports socklen_t.
3727
3728       "d_sockpair"
3729           From d_socket.U:
3730
3731           This variable conditionally defines the "HAS_SOCKETPAIR" symbol,
3732           which indicates that the "BSD" socketpair() is supported.
3733
3734       "d_socks5_init"
3735           From d_socks5_init.U:
3736
3737           This variable conditionally defines the HAS_SOCKS5_INIT symbol,
3738           which indicates to the C program that the socks5_init() routine is
3739           available.
3740
3741       "d_sprintf_returns_strlen"
3742           From d_sprintf_len.U:
3743
3744           This variable defines whether sprintf returns the length of the
3745           string (as per the "ANSI" spec). Some C libraries retain
3746           compatibility with pre-"ANSI" C and return a pointer to the passed
3747           in buffer; for these this variable will be undef.
3748
3749       "d_sqrtl"
3750           From d_sqrtl.U:
3751
3752           This variable conditionally defines the "HAS_SQRTL" symbol, which
3753           indicates to the C program that the sqrtl() routine is available.
3754
3755       "d_srand48_r"
3756           From d_srand48_r.U:
3757
3758           This variable conditionally defines the HAS_SRAND48_R symbol, which
3759           indicates to the C program that the srand48_r() routine is
3760           available.
3761
3762       "d_srandom_r"
3763           From d_srandom_r.U:
3764
3765           This variable conditionally defines the "HAS_SRANDOM_R" symbol,
3766           which indicates to the C program that the srandom_r() routine is
3767           available.
3768
3769       "d_sresgproto"
3770           From d_sresgproto.U:
3771
3772           This variable conditionally defines the "HAS_SETRESGID_PROTO"
3773           symbol, which indicates to the C program that the system provides a
3774           prototype for the setresgid() function.  Otherwise, it is up to the
3775           program to supply one.
3776
3777       "d_sresuproto"
3778           From d_sresuproto.U:
3779
3780           This variable conditionally defines the "HAS_SETRESUID_PROTO"
3781           symbol, which indicates to the C program that the system provides a
3782           prototype for the setresuid() function.  Otherwise, it is up to the
3783           program to supply one.
3784
3785       "d_stat"
3786           From d_stat.U:
3787
3788           This variable conditionally defines "HAS_STAT" if stat() is
3789           available to get file status.
3790
3791       "d_statblks"
3792           From d_statblks.U:
3793
3794           This variable conditionally defines "USE_STAT_BLOCKS" if this
3795           system has a stat structure declaring st_blksize and st_blocks.
3796
3797       "d_statfs_f_flags"
3798           From d_statfs_f_flags.U:
3799
3800           This variable conditionally defines the "HAS_STRUCT_STATFS_F_FLAGS"
3801           symbol, which indicates to struct statfs from has f_flags member.
3802           This kind of struct statfs is coming from sys/mount.h ("BSD"), not
3803           from sys/statfs.h ("SYSV").
3804
3805       "d_statfs_s"
3806           From d_statfs_s.U:
3807
3808           This variable conditionally defines the "HAS_STRUCT_STATFS" symbol,
3809           which indicates that the struct statfs is supported.
3810
3811       "d_static_inline"
3812           From d_static_inline.U:
3813
3814           This variable conditionally defines the "HAS_STATIC_INLINE" symbol,
3815           which indicates that the C compiler supports C99-style static
3816           inline.  That is, the function can't be called from another
3817           translation unit.
3818
3819       "d_statvfs"
3820           From d_statvfs.U:
3821
3822           This variable conditionally defines the "HAS_STATVFS" symbol, which
3823           indicates to the C program that the statvfs() routine is available.
3824
3825       "d_stdio_cnt_lval"
3826           From d_stdstdio.U:
3827
3828           This variable conditionally defines "STDIO_CNT_LVALUE" if the
3829           "FILE_cnt" macro can be used as an lvalue.
3830
3831       "d_stdio_ptr_lval"
3832           From d_stdstdio.U:
3833
3834           This variable conditionally defines "STDIO_PTR_LVALUE" if the
3835           "FILE_ptr" macro can be used as an lvalue.
3836
3837       "d_stdio_ptr_lval_nochange_cnt"
3838           From d_stdstdio.U:
3839
3840           This symbol is defined if using the "FILE_ptr" macro as an lvalue
3841           to increase the pointer by n leaves File_cnt(fp) unchanged.
3842
3843       "d_stdio_ptr_lval_sets_cnt"
3844           From d_stdstdio.U:
3845
3846           This symbol is defined if using the "FILE_ptr" macro as an lvalue
3847           to increase the pointer by n has the side effect of decreasing the
3848           value of File_cnt(fp) by n.
3849
3850       "d_stdio_stream_array"
3851           From stdio_streams.U:
3852
3853           This variable tells whether there is an array holding the stdio
3854           streams.
3855
3856       "d_stdiobase"
3857           From d_stdstdio.U:
3858
3859           This variable conditionally defines "USE_STDIO_BASE" if this system
3860           has a "FILE" structure declaring a usable _base field (or
3861           equivalent) in stdio.h.
3862
3863       "d_stdstdio"
3864           From d_stdstdio.U:
3865
3866           This variable conditionally defines "USE_STDIO_PTR" if this system
3867           has a "FILE" structure declaring usable _ptr and _cnt fields (or
3868           equivalent) in stdio.h.
3869
3870       "d_strchr"
3871           From d_strchr.U:
3872
3873           This variable conditionally defines "HAS_STRCHR" if strchr() and
3874           strrchr() are available for string searching.
3875
3876       "d_strcoll"
3877           From d_strcoll.U:
3878
3879           This variable conditionally defines "HAS_STRCOLL" if strcoll() is
3880           available to compare strings using collating information.
3881
3882       "d_strctcpy"
3883           From d_strctcpy.U:
3884
3885           This variable conditionally defines the "USE_STRUCT_COPY" symbol,
3886           which indicates to the C program that this C compiler knows how to
3887           copy structures.
3888
3889       "d_strerrm"
3890           From d_strerror.U:
3891
3892           This variable holds what Strerror is defined as to translate an
3893           error code condition into an error message string. It could be
3894           "strerror" or a more "complex" macro emulating strerror with
3895           sys_errlist[], or the "unknown" string when both strerror and
3896           sys_errlist are missing.
3897
3898       "d_strerror"
3899           From d_strerror.U:
3900
3901           This variable conditionally defines "HAS_STRERROR" if strerror() is
3902           available to translate error numbers to strings.
3903
3904       "d_strerror_l"
3905           From d_strerror_l.U:
3906
3907           This variable conditionally defines the "HAS_STRERROR_L" symbol,
3908           which indicates to the C program that the strerror_l() routine is
3909           available to return the error message for a given errno value in a
3910           particular locale (identified by a locale_t object).
3911
3912       "d_strerror_r"
3913           From d_strerror_r.U:
3914
3915           This variable conditionally defines the "HAS_STRERROR_R" symbol,
3916           which indicates to the C program that the strerror_r() routine is
3917           available.
3918
3919       "d_strftime"
3920           From d_strftime.U:
3921
3922           This variable conditionally defines the "HAS_STRFTIME" symbol,
3923           which indicates to the C program that the strftime() routine is
3924           available.
3925
3926       "d_strlcat"
3927           From d_strlcat.U:
3928
3929           This variable conditionally defines the "HAS_STRLCAT" symbol, which
3930           indicates to the C program that the strlcat () routine is
3931           available.
3932
3933       "d_strlcpy"
3934           From d_strlcpy.U:
3935
3936           This variable conditionally defines the "HAS_STRLCPY" symbol, which
3937           indicates to the C program that the strlcpy () routine is
3938           available.
3939
3940       "d_strtod"
3941           From d_strtod.U:
3942
3943           This variable conditionally defines the "HAS_STRTOD" symbol, which
3944           indicates to the C program that the strtod() routine is available
3945           to provide better numeric string conversion than atof().
3946
3947       "d_strtol"
3948           From d_strtol.U:
3949
3950           This variable conditionally defines the "HAS_STRTOL" symbol, which
3951           indicates to the C program that the strtol() routine is available
3952           to provide better numeric string conversion than atoi() and
3953           friends.
3954
3955       "d_strtold"
3956           From d_strtold.U:
3957
3958           This variable conditionally defines the "HAS_STRTOLD" symbol, which
3959           indicates to the C program that the strtold() routine is available.
3960
3961       "d_strtoll"
3962           From d_strtoll.U:
3963
3964           This variable conditionally defines the "HAS_STRTOLL" symbol, which
3965           indicates to the C program that the strtoll() routine is available.
3966
3967       "d_strtoq"
3968           From d_strtoq.U:
3969
3970           This variable conditionally defines the "HAS_STRTOQ" symbol, which
3971           indicates to the C program that the strtoq() routine is available.
3972
3973       "d_strtoul"
3974           From d_strtoul.U:
3975
3976           This variable conditionally defines the "HAS_STRTOUL" symbol, which
3977           indicates to the C program that the strtoul() routine is available
3978           to provide conversion of strings to unsigned long.
3979
3980       "d_strtoull"
3981           From d_strtoull.U:
3982
3983           This variable conditionally defines the "HAS_STRTOULL" symbol,
3984           which indicates to the C program that the strtoull() routine is
3985           available.
3986
3987       "d_strtouq"
3988           From d_strtouq.U:
3989
3990           This variable conditionally defines the "HAS_STRTOUQ" symbol, which
3991           indicates to the C program that the strtouq() routine is available.
3992
3993       "d_strxfrm"
3994           From d_strxfrm.U:
3995
3996           This variable conditionally defines "HAS_STRXFRM" if strxfrm() is
3997           available to transform strings.
3998
3999       "d_suidsafe"
4000           From d_dosuid.U:
4001
4002           This variable conditionally defines "SETUID_SCRIPTS_ARE_SECURE_NOW"
4003           if setuid scripts can be secure.  This test looks in /dev/fd/.
4004
4005       "d_symlink"
4006           From d_symlink.U:
4007
4008           This variable conditionally defines the "HAS_SYMLINK" symbol, which
4009           indicates to the C program that the symlink() routine is available
4010           to create symbolic links.
4011
4012       "d_syscall"
4013           From d_syscall.U:
4014
4015           This variable conditionally defines "HAS_SYSCALL" if syscall() is
4016           available call arbitrary system calls.
4017
4018       "d_syscallproto"
4019           From d_syscallproto.U:
4020
4021           This variable conditionally defines the "HAS_SYSCALL_PROTO" symbol,
4022           which indicates to the C program that the system provides a
4023           prototype for the syscall() function.  Otherwise, it is up to the
4024           program to supply one.
4025
4026       "d_sysconf"
4027           From d_sysconf.U:
4028
4029           This variable conditionally defines the "HAS_SYSCONF" symbol, which
4030           indicates to the C program that the sysconf() routine is available
4031           to determine system related limits and options.
4032
4033       "d_sysernlst"
4034           From d_strerror.U:
4035
4036           This variable conditionally defines "HAS_SYS_ERRNOLIST" if
4037           sys_errnolist[] is available to translate error numbers to the
4038           symbolic name.
4039
4040       "d_syserrlst"
4041           From d_strerror.U:
4042
4043           This variable conditionally defines "HAS_SYS_ERRLIST" if
4044           sys_errlist[] is available to translate error numbers to strings.
4045
4046       "d_system"
4047           From d_system.U:
4048
4049           This variable conditionally defines "HAS_SYSTEM" if system() is
4050           available to issue a shell command.
4051
4052       "d_tcgetpgrp"
4053           From d_tcgtpgrp.U:
4054
4055           This variable conditionally defines the "HAS_TCGETPGRP" symbol,
4056           which indicates to the C program that the tcgetpgrp() routine is
4057           available.  to get foreground process group "ID".
4058
4059       "d_tcsetpgrp"
4060           From d_tcstpgrp.U:
4061
4062           This variable conditionally defines the "HAS_TCSETPGRP" symbol,
4063           which indicates to the C program that the tcsetpgrp() routine is
4064           available to set foreground process group "ID".
4065
4066       "d_telldir"
4067           From d_readdir.U:
4068
4069           This variable conditionally defines "HAS_TELLDIR" if telldir() is
4070           available.
4071
4072       "d_telldirproto"
4073           From d_telldirproto.U:
4074
4075           This variable conditionally defines the "HAS_TELLDIR_PROTO" symbol,
4076           which indicates to the C program that the system provides a
4077           prototype for the telldir() function.  Otherwise, it is up to the
4078           program to supply one.
4079
4080       "d_tgamma"
4081           From d_tgamma.U:
4082
4083           This variable conditionally defines the "HAS_TGAMMA" symbol, which
4084           indicates to the C program that the tgamma() routine is available
4085           for the gamma function.  See also d_lgamma.
4086
4087       "d_time"
4088           From d_time.U:
4089
4090           This variable conditionally defines the "HAS_TIME" symbol, which
4091           indicates that the time() routine exists.  The time() routine is
4092           normally provided on "UNIX" systems.
4093
4094       "d_timegm"
4095           From d_timegm.U:
4096
4097           This variable conditionally defines the "HAS_TIMEGM" symbol, which
4098           indicates to the C program that the timegm () routine is available.
4099
4100       "d_times"
4101           From d_times.U:
4102
4103           This variable conditionally defines the "HAS_TIMES" symbol, which
4104           indicates that the times() routine exists.  The times() routine is
4105           normally provided on "UNIX" systems. You may have to include
4106           <sys/times.h>.
4107
4108       "d_tm_tm_gmtoff"
4109           From i_time.U:
4110
4111           This variable conditionally defines "HAS_TM_TM_GMTOFF", which
4112           indicates indicates to the C program that the struct tm has the
4113           tm_gmtoff field.
4114
4115       "d_tm_tm_zone"
4116           From i_time.U:
4117
4118           This variable conditionally defines "HAS_TM_TM_ZONE", which
4119           indicates indicates to the C program that the struct tm has the
4120           tm_zone field.
4121
4122       "d_tmpnam_r"
4123           From d_tmpnam_r.U:
4124
4125           This variable conditionally defines the "HAS_TMPNAM_R" symbol,
4126           which indicates to the C program that the tmpnam_r() routine is
4127           available.
4128
4129       "d_trunc"
4130           From d_trunc.U:
4131
4132           This variable conditionally defines the "HAS_TRUNC" symbol, which
4133           indicates to the C program that the trunc() routine is available to
4134           round doubles towards zero.
4135
4136       "d_truncate"
4137           From d_truncate.U:
4138
4139           This variable conditionally defines "HAS_TRUNCATE" if truncate() is
4140           available to truncate files.
4141
4142       "d_truncl"
4143           From d_truncl.U:
4144
4145           This variable conditionally defines the "HAS_TRUNCL" symbol, which
4146           indicates to the C program that the truncl() routine is available
4147           to round long doubles towards zero. If copysignl is also present,
4148           we can emulate modfl.
4149
4150       "d_ttyname_r"
4151           From d_ttyname_r.U:
4152
4153           This variable conditionally defines the "HAS_TTYNAME_R" symbol,
4154           which indicates to the C program that the ttyname_r() routine is
4155           available.
4156
4157       "d_tzname"
4158           From d_tzname.U:
4159
4160           This variable conditionally defines "HAS_TZNAME" if tzname[] is
4161           available to access timezone names.
4162
4163       "d_u32align"
4164           From d_u32align.U:
4165
4166           This variable tells whether you must access character data through
4167           U32-aligned pointers.
4168
4169       "d_ualarm"
4170           From d_ualarm.U:
4171
4172           This variable conditionally defines the "HAS_UALARM" symbol, which
4173           indicates to the C program that the ualarm() routine is available.
4174
4175       "d_umask"
4176           From d_umask.U:
4177
4178           This variable conditionally defines the "HAS_UMASK" symbol, which
4179           indicates to the C program that the umask() routine is available.
4180           to set and get the value of the file creation mask.
4181
4182       "d_uname"
4183           From d_gethname.U:
4184
4185           This variable conditionally defines the "HAS_UNAME" symbol, which
4186           indicates to the C program that the uname() routine may be used to
4187           derive the host name.
4188
4189       "d_union_semun"
4190           From d_union_semun.U:
4191
4192           This variable conditionally defines "HAS_UNION_SEMUN" if the union
4193           semun is defined by including <sys/sem.h>.
4194
4195       "d_unordered"
4196           From d_unordered.U:
4197
4198           This variable conditionally defines the "HAS_UNORDERED" symbol,
4199           which indicates to the C program that the unordered() routine is
4200           available.
4201
4202       "d_unsetenv"
4203           From d_unsetenv.U:
4204
4205           This variable conditionally defines the "HAS_UNSETENV" symbol,
4206           which indicates to the C program that the unsetenv () routine is
4207           available.
4208
4209       "d_uselocale"
4210           From d_newlocale.U:
4211
4212           This variable conditionally defines the "HAS_USELOCALE" symbol,
4213           which indicates to the C program that the uselocale() routine is
4214           available to set the current locale for the calling thread.
4215
4216       "d_usleep"
4217           From d_usleep.U:
4218
4219           This variable conditionally defines "HAS_USLEEP" if usleep() is
4220           available to do high granularity sleeps.
4221
4222       "d_usleepproto"
4223           From d_usleepproto.U:
4224
4225           This variable conditionally defines the "HAS_USLEEP_PROTO" symbol,
4226           which indicates to the C program that the system provides a
4227           prototype for the usleep() function.  Otherwise, it is up to the
4228           program to supply one.
4229
4230       "d_ustat"
4231           From d_ustat.U:
4232
4233           This variable conditionally defines "HAS_USTAT" if ustat() is
4234           available to query file system statistics by dev_t.
4235
4236       "d_vendorarch"
4237           From vendorarch.U:
4238
4239           This variable conditionally defined "PERL_VENDORARCH".
4240
4241       "d_vendorbin"
4242           From vendorbin.U:
4243
4244           This variable conditionally defines "PERL_VENDORBIN".
4245
4246       "d_vendorlib"
4247           From vendorlib.U:
4248
4249           This variable conditionally defines "PERL_VENDORLIB".
4250
4251       "d_vendorscript"
4252           From vendorscript.U:
4253
4254           This variable conditionally defines "PERL_VENDORSCRIPT".
4255
4256       "d_vfork"
4257           From d_vfork.U:
4258
4259           This variable conditionally defines the "HAS_VFORK" symbol, which
4260           indicates the vfork() routine is available.
4261
4262       "d_void_closedir"
4263           From d_closedir.U:
4264
4265           This variable conditionally defines "VOID_CLOSEDIR" if closedir()
4266           does not return a value.
4267
4268       "d_voidsig"
4269           From d_voidsig.U:
4270
4271           This variable conditionally defines "VOIDSIG" if this system
4272           declares "void (*signal(...))()" in signal.h.  The old way was to
4273           declare it as "int (*signal(...))()".
4274
4275       "d_voidtty"
4276           From i_sysioctl.U:
4277
4278           This variable conditionally defines "USE_IOCNOTTY" to indicate that
4279           the ioctl() call with "TIOCNOTTY" should be used to void tty
4280           association.  Otherwise (on "USG" probably), it is enough to close
4281           the standard file descriptors and do a setpgrp().
4282
4283       "d_volatile"
4284           From d_volatile.U:
4285
4286           This variable conditionally defines the "HASVOLATILE" symbol, which
4287           indicates to the C program that this C compiler knows about the
4288           volatile declaration.
4289
4290       "d_vprintf"
4291           From d_vprintf.U:
4292
4293           This variable conditionally defines the "HAS_VPRINTF" symbol, which
4294           indicates to the C program that the vprintf() routine is available
4295           to printf with a pointer to an argument list.
4296
4297       "d_vsnprintf"
4298           From d_snprintf.U:
4299
4300           This variable conditionally defines the "HAS_VSNPRINTF" symbol,
4301           which indicates to the C program that the vsnprintf () library
4302           function is available.
4303
4304       "d_wait4"
4305           From d_wait4.U:
4306
4307           This variable conditionally defines the HAS_WAIT4 symbol, which
4308           indicates the wait4() routine is available.
4309
4310       "d_waitpid"
4311           From d_waitpid.U:
4312
4313           This variable conditionally defines "HAS_WAITPID" if waitpid() is
4314           available to wait for child process.
4315
4316       "d_wcscmp"
4317           From d_wcscmp.U:
4318
4319           This variable conditionally defines the "HAS_WCSCMP" symbol if the
4320           wcscmp() routine is available and can be used to compare wide
4321           character strings.
4322
4323       "d_wcstombs"
4324           From d_wcstombs.U:
4325
4326           This variable conditionally defines the "HAS_WCSTOMBS" symbol,
4327           which indicates to the C program that the wcstombs() routine is
4328           available to convert wide character strings to multibyte strings.
4329
4330       "d_wcsxfrm"
4331           From d_wcsxfrm.U:
4332
4333           This variable conditionally defines the "HAS_WCSXFRM" symbol if the
4334           wcsxfrm() routine is available and can be used to compare wide
4335           character strings.
4336
4337       "d_wctomb"
4338           From d_wctomb.U:
4339
4340           This variable conditionally defines the "HAS_WCTOMB" symbol, which
4341           indicates to the C program that the wctomb() routine is available
4342           to convert a wide character to a multibyte.
4343
4344       "d_writev"
4345           From d_writev.U:
4346
4347           This variable conditionally defines the "HAS_WRITEV" symbol, which
4348           indicates to the C program that the writev() routine is available.
4349
4350       "d_xenix"
4351           From Guess.U:
4352
4353           This variable conditionally defines the symbol "XENIX", which
4354           alerts the C program that it runs under Xenix.
4355
4356       "date"
4357           From Loc.U:
4358
4359           This variable is used internally by Configure to determine the full
4360           pathname (if any) of the date program.  After Configure runs, the
4361           value is reset to a plain "date" and is not useful.
4362
4363       "db_hashtype"
4364           From i_db.U:
4365
4366           This variable contains the type of the hash structure element in
4367           the <db.h> header file.  In older versions of "DB", it was int,
4368           while in newer ones it is u_int32_t.
4369
4370       "db_prefixtype"
4371           From i_db.U:
4372
4373           This variable contains the type of the prefix structure element in
4374           the <db.h> header file.  In older versions of "DB", it was int,
4375           while in newer ones it is size_t.
4376
4377       "db_version_major"
4378           From i_db.U:
4379
4380           This variable contains the major version number of Berkeley "DB"
4381           found in the <db.h> header file.
4382
4383       "db_version_minor"
4384           From i_db.U:
4385
4386           This variable contains the minor version number of Berkeley "DB"
4387           found in the <db.h> header file.  For "DB" version 1 this is always
4388           0.
4389
4390       "db_version_patch"
4391           From i_db.U:
4392
4393           This variable contains the patch version number of Berkeley "DB"
4394           found in the <db.h> header file.  For "DB" version 1 this is always
4395           0.
4396
4397       "default_inc_excludes_dot"
4398           From defaultincdot.U:
4399
4400           When defined, remove the legacy . from @"INC"
4401
4402       "direntrytype"
4403           From i_dirent.U:
4404
4405           This symbol is set to "struct direct" or "struct dirent" depending
4406           on whether dirent is available or not. You should use this pseudo
4407           type to portably declare your directory entries.
4408
4409       "dlext"
4410           From dlext.U:
4411
4412           This variable contains the extension that is to be used for the
4413           dynamically loaded modules that perl generates.
4414
4415       "dlsrc"
4416           From dlsrc.U:
4417
4418           This variable contains the name of the dynamic loading file that
4419           will be used with the package.
4420
4421       "doubleinfbytes"
4422           From infnan.U:
4423
4424           This variable contains comma-separated list of hexadecimal bytes
4425           for the double precision infinity.
4426
4427       "doublekind"
4428           From longdblfio.U:
4429
4430           This variable, if defined, encodes the type of a double: 1 = "IEEE"
4431           754 32-bit little endian, 2 = "IEEE" 754 32-bit big endian, 3 =
4432           "IEEE" 754 64-bit little endian, 4 = "IEEE" 754 64-bit big endian,
4433           5 = "IEEE" 754 128-bit little endian, 6 = "IEEE" 754 128-bit big
4434           endian, 7 = "IEEE" 754 64-bit mixed endian le-be, 8 = "IEEE" 754
4435           64-bit mixed endian be-le, 9 = "VAX" 32bit little endian F float
4436           format 10 = "VAX" 64bit little endian D float format 11 = "VAX"
4437           64bit little endian G float format 12 = "IBM" 32bit format 13 =
4438           "IBM" 64bit format 14 = Cray 64bit format -1 = unknown format.
4439
4440       "doublemantbits"
4441           From mantbits.U:
4442
4443           This symbol, if defined, tells how many mantissa bits there are in
4444           double precision floating point format.  Note that this is usually
4445           "DBL_MANT_DIG" minus one, since with the standard "IEEE" 754
4446           formats "DBL_MANT_DIG" includes the implicit bit which doesn't
4447           really exist.
4448
4449       "doublenanbytes"
4450           From infnan.U:
4451
4452           This variable contains comma-separated list of hexadecimal bytes
4453           for the double precision not-a-number.
4454
4455       "doublesize"
4456           From doublesize.U:
4457
4458           This variable contains the value of the "DOUBLESIZE" symbol, which
4459           indicates to the C program how many bytes there are in a double.
4460
4461       "drand01"
4462           From randfunc.U:
4463
4464           Indicates the macro to be used to generate normalized random
4465           numbers.  Uses randfunc, often divided by (double) (((unsigned
4466           long) 1 << randbits)) in order to normalize the result.  In C
4467           programs, the macro "Drand01" is mapped to drand01.
4468
4469       "drand48_r_proto"
4470           From d_drand48_r.U:
4471
4472           This variable encodes the prototype of drand48_r.  It is zero if
4473           d_drand48_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
4474           of reentr.h if d_drand48_r is defined.
4475
4476       "dtrace"
4477           From usedtrace.U:
4478
4479           This variable holds the location of the dtrace executable.
4480
4481       "dtraceobject"
4482           From dtraceobject.U:
4483
4484           Whether we need to build an object file with the dtrace tool.
4485
4486       "dtracexnolibs"
4487           From dtraceobject.U:
4488
4489           Whether dtrace accepts -xnolibs.  If available we call dtrace -h
4490           and dtrace -G with -xnolibs to allow dtrace to run in a jail on
4491           FreeBSD.
4492
4493       "dynamic_ext"
4494           From Extensions.U:
4495
4496           This variable holds a list of "XS" extension files we want to link
4497           dynamically into the package.  It is used by Makefile.
4498
4499   e
4500       "eagain"
4501           From nblock_io.U:
4502
4503           This variable bears the symbolic errno code set by read() when no
4504           data is present on the file and non-blocking I/O was enabled
4505           (otherwise, read() blocks naturally).
4506
4507       "ebcdic"
4508           From ebcdic.U:
4509
4510           This variable conditionally defines "EBCDIC" if this system uses
4511           "EBCDIC" encoding.
4512
4513       "echo"
4514           From Loc.U:
4515
4516           This variable is used internally by Configure to determine the full
4517           pathname (if any) of the echo program.  After Configure runs, the
4518           value is reset to a plain "echo" and is not useful.
4519
4520       "egrep"
4521           From Loc.U:
4522
4523           This variable is used internally by Configure to determine the full
4524           pathname (if any) of the egrep program.  After Configure runs, the
4525           value is reset to a plain "egrep" and is not useful.
4526
4527       "emacs"
4528           From Loc.U:
4529
4530           This variable is defined but not used by Configure.  The value is
4531           the empty string and is not useful.
4532
4533       "endgrent_r_proto"
4534           From d_endgrent_r.U:
4535
4536           This variable encodes the prototype of endgrent_r.  It is zero if
4537           d_endgrent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4538           macros of reentr.h if d_endgrent_r is defined.
4539
4540       "endhostent_r_proto"
4541           From d_endhostent_r.U:
4542
4543           This variable encodes the prototype of endhostent_r.  It is zero if
4544           d_endhostent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4545           macros of reentr.h if d_endhostent_r is defined.
4546
4547       "endnetent_r_proto"
4548           From d_endnetent_r.U:
4549
4550           This variable encodes the prototype of endnetent_r.  It is zero if
4551           d_endnetent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4552           macros of reentr.h if d_endnetent_r is defined.
4553
4554       "endprotoent_r_proto"
4555           From d_endprotoent_r.U:
4556
4557           This variable encodes the prototype of endprotoent_r.  It is zero
4558           if d_endprotoent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4559           macros of reentr.h if d_endprotoent_r is defined.
4560
4561       "endpwent_r_proto"
4562           From d_endpwent_r.U:
4563
4564           This variable encodes the prototype of endpwent_r.  It is zero if
4565           d_endpwent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4566           macros of reentr.h if d_endpwent_r is defined.
4567
4568       "endservent_r_proto"
4569           From d_endservent_r.U:
4570
4571           This variable encodes the prototype of endservent_r.  It is zero if
4572           d_endservent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4573           macros of reentr.h if d_endservent_r is defined.
4574
4575       "eunicefix"
4576           From Init.U:
4577
4578           When running under Eunice this variable contains a command which
4579           will convert a shell script to the proper form of text file for it
4580           to be executable by the shell.  On other systems it is a no-op.
4581
4582       "exe_ext"
4583           From Unix.U:
4584
4585           This is an old synonym for _exe.
4586
4587       "expr"
4588           From Loc.U:
4589
4590           This variable is used internally by Configure to determine the full
4591           pathname (if any) of the expr program.  After Configure runs, the
4592           value is reset to a plain "expr" and is not useful.
4593
4594       "extensions"
4595           From Extensions.U:
4596
4597           This variable holds a list of all extension files (both "XS" and
4598           non-xs) installed with the package.  It is propagated to Config.pm
4599           and is typically used to test whether a particular extension is
4600           available.
4601
4602       "extern_C"
4603           From Csym.U:
4604
4605           "ANSI" C requires "extern" where C++ requires 'extern "C"'. This
4606           variable can be used in Configure to do the right thing.
4607
4608       "extras"
4609           From Extras.U:
4610
4611           This variable holds a list of extra modules to install.
4612
4613   f
4614       "fflushall"
4615           From fflushall.U:
4616
4617           This symbol, if defined, tells that to flush all pending stdio
4618           output one must loop through all the stdio file handles stored in
4619           an array and fflush them.  Note that if fflushNULL is defined,
4620           fflushall will not even be probed for and will be left undefined.
4621
4622       "fflushNULL"
4623           From fflushall.U:
4624
4625           This symbol, if defined, tells that fflush("NULL") correctly
4626           flushes all pending stdio output without side effects. In
4627           particular, on some platforms calling fflush("NULL") *still*
4628           corrupts "STDIN" if it is a pipe.
4629
4630       "find"
4631           From Loc.U:
4632
4633           This variable is defined but not used by Configure.  The value is
4634           the empty string and is not useful.
4635
4636       "firstmakefile"
4637           From Unix.U:
4638
4639           This variable defines the first file searched by make.  On unix, it
4640           is makefile (then Makefile).  On case-insensitive systems, it might
4641           be something else.  This is only used to deal with convoluted make
4642           depend tricks.
4643
4644       "flex"
4645           From Loc.U:
4646
4647           This variable is defined but not used by Configure.  The value is
4648           the empty string and is not useful.
4649
4650       "fpossize"
4651           From fpossize.U:
4652
4653           This variable contains the size of a fpostype in bytes.
4654
4655       "fpostype"
4656           From fpostype.U:
4657
4658           This variable defines Fpos_t to be something like fpos_t, long,
4659           uint, or whatever type is used to declare file positions in libc.
4660
4661       "freetype"
4662           From mallocsrc.U:
4663
4664           This variable contains the return type of free().  It is usually
4665           void, but occasionally int.
4666
4667       "from"
4668           From Cross.U:
4669
4670           This variable contains the command used by Configure to copy files
4671           from the target host.  Useful and available only during Perl build.
4672           The string ":" if not cross-compiling.
4673
4674       "full_ar"
4675           From Loc_ar.U:
4676
4677           This variable contains the full pathname to "ar", whether or not
4678           the user has specified "portability".  This is only used in the
4679           Makefile.SH.
4680
4681       "full_csh"
4682           From d_csh.U:
4683
4684           This variable contains the full pathname to "csh", whether or not
4685           the user has specified "portability".  This is only used in the
4686           compiled C program, and we assume that all systems which can share
4687           this executable will have the same full pathname to csh.
4688
4689       "full_sed"
4690           From Loc_sed.U:
4691
4692           This variable contains the full pathname to "sed", whether or not
4693           the user has specified "portability".  This is only used in the
4694           compiled C program, and we assume that all systems which can share
4695           this executable will have the same full pathname to sed.
4696
4697   g
4698       "gccansipedantic"
4699           From gccvers.U:
4700
4701           If "GNU" cc (gcc) is used, this variable will enable (if set) the
4702           -ansi and -pedantic ccflags for building core files (through cflags
4703           script). (See Porting/pumpkin.pod for full description).
4704
4705       "gccosandvers"
4706           From gccvers.U:
4707
4708           If "GNU" cc (gcc) is used, this variable holds the operating system
4709           and version used to compile gcc.  It is set to '' if not gcc, or if
4710           nothing useful can be parsed as the os version.
4711
4712       "gccversion"
4713           From gccvers.U:
4714
4715           If "GNU" cc (gcc) is used, this variable holds 1 or 2 to indicate
4716           whether the compiler is version 1 or 2.  This is used in setting
4717           some of the default cflags.  It is set to '' if not gcc.
4718
4719       "getgrent_r_proto"
4720           From d_getgrent_r.U:
4721
4722           This variable encodes the prototype of getgrent_r.  It is zero if
4723           d_getgrent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4724           macros of reentr.h if d_getgrent_r is defined.
4725
4726       "getgrgid_r_proto"
4727           From d_getgrgid_r.U:
4728
4729           This variable encodes the prototype of getgrgid_r.  It is zero if
4730           d_getgrgid_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4731           macros of reentr.h if d_getgrgid_r is defined.
4732
4733       "getgrnam_r_proto"
4734           From d_getgrnam_r.U:
4735
4736           This variable encodes the prototype of getgrnam_r.  It is zero if
4737           d_getgrnam_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4738           macros of reentr.h if d_getgrnam_r is defined.
4739
4740       "gethostbyaddr_r_proto"
4741           From d_gethostbyaddr_r.U:
4742
4743           This variable encodes the prototype of gethostbyaddr_r.  It is zero
4744           if d_gethostbyaddr_r is undef, and one of the
4745           "REENTRANT_PROTO_T_ABC" macros of reentr.h if d_gethostbyaddr_r is
4746           defined.
4747
4748       "gethostbyname_r_proto"
4749           From d_gethostbyname_r.U:
4750
4751           This variable encodes the prototype of gethostbyname_r.  It is zero
4752           if d_gethostbyname_r is undef, and one of the
4753           "REENTRANT_PROTO_T_ABC" macros of reentr.h if d_gethostbyname_r is
4754           defined.
4755
4756       "gethostent_r_proto"
4757           From d_gethostent_r.U:
4758
4759           This variable encodes the prototype of gethostent_r.  It is zero if
4760           d_gethostent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4761           macros of reentr.h if d_gethostent_r is defined.
4762
4763       "getlogin_r_proto"
4764           From d_getlogin_r.U:
4765
4766           This variable encodes the prototype of getlogin_r.  It is zero if
4767           d_getlogin_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4768           macros of reentr.h if d_getlogin_r is defined.
4769
4770       "getnetbyaddr_r_proto"
4771           From d_getnetbyaddr_r.U:
4772
4773           This variable encodes the prototype of getnetbyaddr_r.  It is zero
4774           if d_getnetbyaddr_r is undef, and one of the
4775           "REENTRANT_PROTO_T_ABC" macros of reentr.h if d_getnetbyaddr_r is
4776           defined.
4777
4778       "getnetbyname_r_proto"
4779           From d_getnetbyname_r.U:
4780
4781           This variable encodes the prototype of getnetbyname_r.  It is zero
4782           if d_getnetbyname_r is undef, and one of the
4783           "REENTRANT_PROTO_T_ABC" macros of reentr.h if d_getnetbyname_r is
4784           defined.
4785
4786       "getnetent_r_proto"
4787           From d_getnetent_r.U:
4788
4789           This variable encodes the prototype of getnetent_r.  It is zero if
4790           d_getnetent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4791           macros of reentr.h if d_getnetent_r is defined.
4792
4793       "getprotobyname_r_proto"
4794           From d_getprotobyname_r.U:
4795
4796           This variable encodes the prototype of getprotobyname_r.  It is
4797           zero if d_getprotobyname_r is undef, and one of the
4798           "REENTRANT_PROTO_T_ABC" macros of reentr.h if d_getprotobyname_r is
4799           defined.
4800
4801       "getprotobynumber_r_proto"
4802           From d_getprotobynumber_r.U:
4803
4804           This variable encodes the prototype of getprotobynumber_r.  It is
4805           zero if d_getprotobynumber_r is undef, and one of the
4806           "REENTRANT_PROTO_T_ABC" macros of reentr.h if d_getprotobynumber_r
4807           is defined.
4808
4809       "getprotoent_r_proto"
4810           From d_getprotoent_r.U:
4811
4812           This variable encodes the prototype of getprotoent_r.  It is zero
4813           if d_getprotoent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4814           macros of reentr.h if d_getprotoent_r is defined.
4815
4816       "getpwent_r_proto"
4817           From d_getpwent_r.U:
4818
4819           This variable encodes the prototype of getpwent_r.  It is zero if
4820           d_getpwent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4821           macros of reentr.h if d_getpwent_r is defined.
4822
4823       "getpwnam_r_proto"
4824           From d_getpwnam_r.U:
4825
4826           This variable encodes the prototype of getpwnam_r.  It is zero if
4827           d_getpwnam_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4828           macros of reentr.h if d_getpwnam_r is defined.
4829
4830       "getpwuid_r_proto"
4831           From d_getpwuid_r.U:
4832
4833           This variable encodes the prototype of getpwuid_r.  It is zero if
4834           d_getpwuid_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4835           macros of reentr.h if d_getpwuid_r is defined.
4836
4837       "getservbyname_r_proto"
4838           From d_getservbyname_r.U:
4839
4840           This variable encodes the prototype of getservbyname_r.  It is zero
4841           if d_getservbyname_r is undef, and one of the
4842           "REENTRANT_PROTO_T_ABC" macros of reentr.h if d_getservbyname_r is
4843           defined.
4844
4845       "getservbyport_r_proto"
4846           From d_getservbyport_r.U:
4847
4848           This variable encodes the prototype of getservbyport_r.  It is zero
4849           if d_getservbyport_r is undef, and one of the
4850           "REENTRANT_PROTO_T_ABC" macros of reentr.h if d_getservbyport_r is
4851           defined.
4852
4853       "getservent_r_proto"
4854           From d_getservent_r.U:
4855
4856           This variable encodes the prototype of getservent_r.  It is zero if
4857           d_getservent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4858           macros of reentr.h if d_getservent_r is defined.
4859
4860       "getspnam_r_proto"
4861           From d_getspnam_r.U:
4862
4863           This variable encodes the prototype of getspnam_r.  It is zero if
4864           d_getspnam_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
4865           macros of reentr.h if d_getspnam_r is defined.
4866
4867       "gidformat"
4868           From gidf.U:
4869
4870           This variable contains the format string used for printing a Gid_t.
4871
4872       "gidsign"
4873           From gidsign.U:
4874
4875           This variable contains the signedness of a gidtype.  1 for
4876           unsigned, -1 for signed.
4877
4878       "gidsize"
4879           From gidsize.U:
4880
4881           This variable contains the size of a gidtype in bytes.
4882
4883       "gidtype"
4884           From gidtype.U:
4885
4886           This variable defines Gid_t to be something like gid_t, int,
4887           ushort, or whatever type is used to declare the return type of
4888           getgid().  Typically, it is the type of group ids in the kernel.
4889
4890       "glibpth"
4891           From libpth.U:
4892
4893           This variable holds the general path (space-separated) used to find
4894           libraries.  It may contain directories that do not exist on this
4895           platform, libpth is the cleaned-up version.
4896
4897       "gmake"
4898           From Loc.U:
4899
4900           This variable is used internally by Configure to determine the full
4901           pathname (if any) of the gmake program.  After Configure runs, the
4902           value is reset to a plain "gmake" and is not useful.
4903
4904       "gmtime_r_proto"
4905           From d_gmtime_r.U:
4906
4907           This variable encodes the prototype of gmtime_r.  It is zero if
4908           d_gmtime_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
4909           of reentr.h if d_gmtime_r is defined.
4910
4911       "gnulibc_version"
4912           From d_gnulibc.U:
4913
4914           This variable contains the version number of the "GNU" C library.
4915           It is usually something like 2.2.5.  It is a plain '' if this is
4916           not the "GNU" C library, or if the version is unknown.
4917
4918       "grep"
4919           From Loc.U:
4920
4921           This variable is used internally by Configure to determine the full
4922           pathname (if any) of the grep program.  After Configure runs, the
4923           value is reset to a plain "grep" and is not useful.
4924
4925       "groupcat"
4926           From nis.U:
4927
4928           This variable contains a command that produces the text of the
4929           /etc/group file.  This is normally "cat /etc/group", but can be
4930           "ypcat group" when "NIS" is used.  On some systems, such as os390,
4931           there may be no equivalent command, in which case this variable is
4932           unset.
4933
4934       "groupstype"
4935           From groupstype.U:
4936
4937           This variable defines Groups_t to be something like gid_t, int,
4938           ushort, or whatever type is used for the second argument to
4939           getgroups() and setgroups().  Usually, this is the same as gidtype
4940           (gid_t), but sometimes it isn't.
4941
4942       "gzip"
4943           From Loc.U:
4944
4945           This variable is used internally by Configure to determine the full
4946           pathname (if any) of the gzip program.  After Configure runs, the
4947           value is reset to a plain "gzip" and is not useful.
4948
4949   h
4950       "h_fcntl"
4951           From h_fcntl.U:
4952
4953           This is variable gets set in various places to tell i_fcntl that
4954           <fcntl.h> should be included.
4955
4956       "h_sysfile"
4957           From h_sysfile.U:
4958
4959           This is variable gets set in various places to tell i_sys_file that
4960           <sys/file.h> should be included.
4961
4962       "hint"
4963           From Oldconfig.U:
4964
4965           Gives the type of hints used for previous answers. May be one of
4966           "default", "recommended" or "previous".
4967
4968       "hostcat"
4969           From nis.U:
4970
4971           This variable contains a command that produces the text of the
4972           /etc/hosts file.  This is normally "cat /etc/hosts", but can be
4973           "ypcat hosts" when "NIS" is used.  On some systems, such as os390,
4974           there may be no equivalent command, in which case this variable is
4975           unset.
4976
4977       "hostgenerate"
4978           From Cross.U:
4979
4980           This variable contains the path to a generate_uudmap binary that
4981           can be run on the host "OS" when cross-compiling.  Useful and
4982           available only during Perl build.  Empty string '' if not cross-
4983           compiling.
4984
4985       "hostosname"
4986           From Cross.U:
4987
4988           This variable contains the original value of $^O for hostperl when
4989           cross-compiling.  This is useful to pick the proper tools when
4990           running build code in the host.  Empty string '' if not cross-
4991           compiling.
4992
4993       "hostperl"
4994           From Cross.U:
4995
4996           This variable contains the path to a miniperl binary that can be
4997           run on the host "OS" when cross-compiling.  Useful and available
4998           only during Perl build.  Empty string '' if not cross-compiling.
4999
5000       "html1dir"
5001           From html1dir.U:
5002
5003           This variable contains the name of the directory in which html
5004           source pages are to be put.  This directory is for pages that
5005           describe whole programs, not libraries or modules.  It is intended
5006           to correspond roughly to section 1 of the Unix manuals.
5007
5008       "html1direxp"
5009           From html1dir.U:
5010
5011           This variable is the same as the html1dir variable, but is filename
5012           expanded at configuration time, for convenient use in makefiles.
5013
5014       "html3dir"
5015           From html3dir.U:
5016
5017           This variable contains the name of the directory in which html
5018           source pages are to be put.  This directory is for pages that
5019           describe libraries or modules.  It is intended to correspond
5020           roughly to section 3 of the Unix manuals.
5021
5022       "html3direxp"
5023           From html3dir.U:
5024
5025           This variable is the same as the html3dir variable, but is filename
5026           expanded at configuration time, for convenient use in makefiles.
5027
5028   i
5029       "i16size"
5030           From perlxv.U:
5031
5032           This variable is the size of an I16 in bytes.
5033
5034       "i16type"
5035           From perlxv.U:
5036
5037           This variable contains the C type used for Perl's I16.
5038
5039       "i32size"
5040           From perlxv.U:
5041
5042           This variable is the size of an I32 in bytes.
5043
5044       "i32type"
5045           From perlxv.U:
5046
5047           This variable contains the C type used for Perl's I32.
5048
5049       "i64size"
5050           From perlxv.U:
5051
5052           This variable is the size of an I64 in bytes.
5053
5054       "i64type"
5055           From perlxv.U:
5056
5057           This variable contains the C type used for Perl's I64.
5058
5059       "i8size"
5060           From perlxv.U:
5061
5062           This variable is the size of an I8 in bytes.
5063
5064       "i8type"
5065           From perlxv.U:
5066
5067           This variable contains the C type used for Perl's I8.
5068
5069       "i_arpainet"
5070           From i_arpainet.U:
5071
5072           This variable conditionally defines the "I_ARPA_INET" symbol, and
5073           indicates whether a C program should include <arpa/inet.h>.
5074
5075       "i_assert"
5076           From i_assert.U:
5077
5078           This variable conditionally defines the "I_ASSERT" symbol, which
5079           indicates to the C program that <assert.h> exists and could be
5080           included.
5081
5082       "i_bfd"
5083           From i_bfd.U:
5084
5085           This variable conditionally defines the "I_BFD" symbol, and
5086           indicates whether a C program can include <bfd.h>.
5087
5088       "i_bsdioctl"
5089           From i_sysioctl.U:
5090
5091           This variable conditionally defines the "I_SYS_BSDIOCTL" symbol,
5092           which indicates to the C program that <sys/bsdioctl.h> exists and
5093           should be included.
5094
5095       "i_crypt"
5096           From i_crypt.U:
5097
5098           This variable conditionally defines the "I_CRYPT" symbol, and
5099           indicates whether a C program should include <crypt.h>.
5100
5101       "i_db"
5102           From i_db.U:
5103
5104           This variable conditionally defines the "I_DB" symbol, and
5105           indicates whether a C program may include Berkeley's "DB" include
5106           file <db.h>.
5107
5108       "i_dbm"
5109           From i_dbm.U:
5110
5111           This variable conditionally defines the "I_DBM" symbol, which
5112           indicates to the C program that <dbm.h> exists and should be
5113           included.
5114
5115       "i_dirent"
5116           From i_dirent.U:
5117
5118           This variable conditionally defines "I_DIRENT", which indicates to
5119           the C program that it should include <dirent.h>.
5120
5121       "i_dlfcn"
5122           From i_dlfcn.U:
5123
5124           This variable conditionally defines the "I_DLFCN" symbol, which
5125           indicates to the C program that <dlfcn.h> exists and should be
5126           included.
5127
5128       "i_execinfo"
5129           From i_execinfo.U:
5130
5131           This variable conditionally defines the "I_EXECINFO" symbol, and
5132           indicates whether a C program may include <execinfo.h>, for
5133           backtrace() support.
5134
5135       "i_fcntl"
5136           From i_fcntl.U:
5137
5138           This variable controls the value of "I_FCNTL" (which tells the C
5139           program to include <fcntl.h>).
5140
5141       "i_fenv"
5142           From i_fenv.U:
5143
5144           This variable conditionally defines the "I_FENV" symbol, which
5145           indicates to the C program that <fenv.h> exists and should be
5146           included.
5147
5148       "i_float"
5149           From i_float.U:
5150
5151           This variable conditionally defines the "I_FLOAT" symbol, and
5152           indicates whether a C program may include <float.h> to get symbols
5153           like "DBL_MAX" or "DBL_MIN", i.e. machine dependent floating point
5154           values.
5155
5156       "i_fp"
5157           From i_fp.U:
5158
5159           This variable conditionally defines the "I_FP" symbol, and
5160           indicates whether a C program should include <fp.h>.
5161
5162       "i_fp_class"
5163           From i_fp_class.U:
5164
5165           This variable conditionally defines the "I_FP_CLASS" symbol, and
5166           indicates whether a C program should include <fp_class.h>.
5167
5168       "i_gdbm"
5169           From i_gdbm.U:
5170
5171           This variable conditionally defines the "I_GDBM" symbol, which
5172           indicates to the C program that <gdbm.h> exists and should be
5173           included.
5174
5175       "i_gdbm_ndbm"
5176           From i_ndbm.U:
5177
5178           This variable conditionally defines the "I_GDBM_NDBM" symbol, which
5179           indicates to the C program that <gdbm-ndbm.h> exists and should be
5180           included.  This is the location of the ndbm.h compatibility file in
5181           Debian 4.0.
5182
5183       "i_gdbmndbm"
5184           From i_ndbm.U:
5185
5186           This variable conditionally defines the "I_GDBMNDBM" symbol, which
5187           indicates to the C program that <gdbm/ndbm.h> exists and should be
5188           included.  This was the location of the ndbm.h compatibility file
5189           in RedHat 7.1.
5190
5191       "i_grp"
5192           From i_grp.U:
5193
5194           This variable conditionally defines the "I_GRP" symbol, and
5195           indicates whether a C program should include <grp.h>.
5196
5197       "i_ieeefp"
5198           From i_ieeefp.U:
5199
5200           This variable conditionally defines the "I_IEEEFP" symbol, and
5201           indicates whether a C program should include <ieeefp.h>.
5202
5203       "i_inttypes"
5204           From i_inttypes.U:
5205
5206           This variable conditionally defines the "I_INTTYPES" symbol, and
5207           indicates whether a C program should include <inttypes.h>.
5208
5209       "i_langinfo"
5210           From i_langinfo.U:
5211
5212           This variable conditionally defines the "I_LANGINFO" symbol, and
5213           indicates whether a C program should include <langinfo.h>.
5214
5215       "i_libutil"
5216           From i_libutil.U:
5217
5218           This variable conditionally defines the "I_LIBUTIL" symbol, and
5219           indicates whether a C program should include <libutil.h>.
5220
5221       "i_limits"
5222           From i_limits.U:
5223
5224           This variable conditionally defines the "I_LIMITS" symbol, and
5225           indicates whether a C program may include <limits.h> to get symbols
5226           like "WORD_BIT" and friends.
5227
5228       "i_locale"
5229           From i_locale.U:
5230
5231           This variable conditionally defines the "I_LOCALE" symbol, and
5232           indicates whether a C program should include <locale.h>.
5233
5234       "i_machcthr"
5235           From i_machcthr.U:
5236
5237           This variable conditionally defines the "I_MACH_CTHREADS" symbol,
5238           and indicates whether a C program should include <mach/cthreads.h>.
5239
5240       "i_malloc"
5241           From i_malloc.U:
5242
5243           This variable conditionally defines the "I_MALLOC" symbol, and
5244           indicates whether a C program should include <malloc.h>.
5245
5246       "i_mallocmalloc"
5247           From i_mallocmalloc.U:
5248
5249           This variable conditionally defines the "I_MALLOCMALLOC" symbol,
5250           and indicates whether a C program should include <malloc/malloc.h>.
5251
5252       "i_math"
5253           From i_math.U:
5254
5255           This variable conditionally defines the "I_MATH" symbol, and
5256           indicates whether a C program may include <math.h>.
5257
5258       "i_memory"
5259           From i_memory.U:
5260
5261           This variable conditionally defines the "I_MEMORY" symbol, and
5262           indicates whether a C program should include <memory.h>.
5263
5264       "i_mntent"
5265           From i_mntent.U:
5266
5267           This variable conditionally defines the "I_MNTENT" symbol, and
5268           indicates whether a C program should include <mntent.h>.
5269
5270       "i_ndbm"
5271           From i_ndbm.U:
5272
5273           This variable conditionally defines the "I_NDBM" symbol, which
5274           indicates to the C program that <ndbm.h> exists and should be
5275           included.
5276
5277       "i_netdb"
5278           From i_netdb.U:
5279
5280           This variable conditionally defines the "I_NETDB" symbol, and
5281           indicates whether a C program should include <netdb.h>.
5282
5283       "i_neterrno"
5284           From i_neterrno.U:
5285
5286           This variable conditionally defines the "I_NET_ERRNO" symbol, which
5287           indicates to the C program that <net/errno.h> exists and should be
5288           included.
5289
5290       "i_netinettcp"
5291           From i_netinettcp.U:
5292
5293           This variable conditionally defines the "I_NETINET_TCP" symbol, and
5294           indicates whether a C program should include <netinet/tcp.h>.
5295
5296       "i_niin"
5297           From i_niin.U:
5298
5299           This variable conditionally defines "I_NETINET_IN", which indicates
5300           to the C program that it should include <netinet/in.h>. Otherwise,
5301           you may try <sys/in.h>.
5302
5303       "i_poll"
5304           From i_poll.U:
5305
5306           This variable conditionally defines the "I_POLL" symbol, and
5307           indicates whether a C program should include <poll.h>.
5308
5309       "i_prot"
5310           From i_prot.U:
5311
5312           This variable conditionally defines the "I_PROT" symbol, and
5313           indicates whether a C program should include <prot.h>.
5314
5315       "i_pthread"
5316           From i_pthread.U:
5317
5318           This variable conditionally defines the "I_PTHREAD" symbol, and
5319           indicates whether a C program should include <pthread.h>.
5320
5321       "i_pwd"
5322           From i_pwd.U:
5323
5324           This variable conditionally defines "I_PWD", which indicates to the
5325           C program that it should include <pwd.h>.
5326
5327       "i_quadmath"
5328           From i_quadmath.U:
5329
5330           This variable conditionally defines "I_QUADMATH", which indicates
5331           to the C program that it should include <quadmath.h>.
5332
5333       "i_rpcsvcdbm"
5334           From i_dbm.U:
5335
5336           This variable conditionally defines the "I_RPCSVC_DBM" symbol,
5337           which indicates to the C program that <rpcsvc/dbm.h> exists and
5338           should be included.  Some System V systems might need this instead
5339           of <dbm.h>.
5340
5341       "i_sgtty"
5342           From i_termio.U:
5343
5344           This variable conditionally defines the "I_SGTTY" symbol, which
5345           indicates to the C program that it should include <sgtty.h> rather
5346           than <termio.h>.
5347
5348       "i_shadow"
5349           From i_shadow.U:
5350
5351           This variable conditionally defines the "I_SHADOW" symbol, and
5352           indicates whether a C program should include <shadow.h>.
5353
5354       "i_socks"
5355           From i_socks.U:
5356
5357           This variable conditionally defines the "I_SOCKS" symbol, and
5358           indicates whether a C program should include <socks.h>.
5359
5360       "i_stdarg"
5361           From i_varhdr.U:
5362
5363           This variable conditionally defines the "I_STDARG" symbol, which
5364           indicates to the C program that <stdarg.h> exists and should be
5365           included.
5366
5367       "i_stdbool"
5368           From i_stdbool.U:
5369
5370           This variable conditionally defines the "I_STDBOOL" symbol, which
5371           indicates to the C program that <stdbool.h> exists and should be
5372           included.
5373
5374       "i_stddef"
5375           From i_stddef.U:
5376
5377           This variable conditionally defines the "I_STDDEF" symbol, which
5378           indicates to the C program that <stddef.h> exists and should be
5379           included.
5380
5381       "i_stdint"
5382           From i_stdint.U:
5383
5384           This variable conditionally defines the "I_STDINT" symbol, which
5385           indicates to the C program that <stdint.h> exists and should be
5386           included.
5387
5388       "i_stdlib"
5389           From i_stdlib.U:
5390
5391           This variable conditionally defines the "I_STDLIB" symbol, which
5392           indicates to the C program that <stdlib.h> exists and should be
5393           included.
5394
5395       "i_string"
5396           From i_string.U:
5397
5398           This variable conditionally defines the "I_STRING" symbol, which
5399           indicates that <string.h> should be included rather than
5400           <strings.h>.
5401
5402       "i_sunmath"
5403           From i_sunmath.U:
5404
5405           This variable conditionally defines the "I_SUNMATH" symbol, and
5406           indicates whether a C program should include <sunmath.h>.
5407
5408       "i_sysaccess"
5409           From i_sysaccess.U:
5410
5411           This variable conditionally defines the "I_SYS_ACCESS" symbol, and
5412           indicates whether a C program should include <sys/access.h>.
5413
5414       "i_sysdir"
5415           From i_sysdir.U:
5416
5417           This variable conditionally defines the "I_SYS_DIR" symbol, and
5418           indicates whether a C program should include <sys/dir.h>.
5419
5420       "i_sysfile"
5421           From i_sysfile.U:
5422
5423           This variable conditionally defines the "I_SYS_FILE" symbol, and
5424           indicates whether a C program should include <sys/file.h> to get
5425           "R_OK" and friends.
5426
5427       "i_sysfilio"
5428           From i_sysioctl.U:
5429
5430           This variable conditionally defines the "I_SYS_FILIO" symbol, which
5431           indicates to the C program that <sys/filio.h> exists and should be
5432           included in preference to <sys/ioctl.h>.
5433
5434       "i_sysin"
5435           From i_niin.U:
5436
5437           This variable conditionally defines "I_SYS_IN", which indicates to
5438           the C program that it should include <sys/in.h> instead of
5439           <netinet/in.h>.
5440
5441       "i_sysioctl"
5442           From i_sysioctl.U:
5443
5444           This variable conditionally defines the "I_SYS_IOCTL" symbol, which
5445           indicates to the C program that <sys/ioctl.h> exists and should be
5446           included.
5447
5448       "i_syslog"
5449           From i_syslog.U:
5450
5451           This variable conditionally defines the "I_SYSLOG" symbol, and
5452           indicates whether a C program should include <syslog.h>.
5453
5454       "i_sysmman"
5455           From i_sysmman.U:
5456
5457           This variable conditionally defines the "I_SYS_MMAN" symbol, and
5458           indicates whether a C program should include <sys/mman.h>.
5459
5460       "i_sysmode"
5461           From i_sysmode.U:
5462
5463           This variable conditionally defines the "I_SYSMODE" symbol, and
5464           indicates whether a C program should include <sys/mode.h>.
5465
5466       "i_sysmount"
5467           From i_sysmount.U:
5468
5469           This variable conditionally defines the "I_SYSMOUNT" symbol, and
5470           indicates whether a C program should include <sys/mount.h>.
5471
5472       "i_sysndir"
5473           From i_sysndir.U:
5474
5475           This variable conditionally defines the "I_SYS_NDIR" symbol, and
5476           indicates whether a C program should include <sys/ndir.h>.
5477
5478       "i_sysparam"
5479           From i_sysparam.U:
5480
5481           This variable conditionally defines the "I_SYS_PARAM" symbol, and
5482           indicates whether a C program should include <sys/param.h>.
5483
5484       "i_syspoll"
5485           From i_syspoll.U:
5486
5487           This variable conditionally defines the "I_SYS_POLL" symbol, which
5488           indicates to the C program that it should include <sys/poll.h>.
5489
5490       "i_sysresrc"
5491           From i_sysresrc.U:
5492
5493           This variable conditionally defines the "I_SYS_RESOURCE" symbol,
5494           and indicates whether a C program should include <sys/resource.h>.
5495
5496       "i_syssecrt"
5497           From i_syssecrt.U:
5498
5499           This variable conditionally defines the "I_SYS_SECURITY" symbol,
5500           and indicates whether a C program should include <sys/security.h>.
5501
5502       "i_sysselct"
5503           From i_sysselct.U:
5504
5505           This variable conditionally defines "I_SYS_SELECT", which indicates
5506           to the C program that it should include <sys/select.h> in order to
5507           get the definition of struct timeval.
5508
5509       "i_syssockio"
5510           From i_sysioctl.U:
5511
5512           This variable conditionally defines "I_SYS_SOCKIO" to indicate to
5513           the C program that socket ioctl codes may be found in
5514           <sys/sockio.h> instead of <sys/ioctl.h>.
5515
5516       "i_sysstat"
5517           From i_sysstat.U:
5518
5519           This variable conditionally defines the "I_SYS_STAT" symbol, and
5520           indicates whether a C program should include <sys/stat.h>.
5521
5522       "i_sysstatfs"
5523           From i_sysstatfs.U:
5524
5525           This variable conditionally defines the "I_SYSSTATFS" symbol, and
5526           indicates whether a C program should include <sys/statfs.h>.
5527
5528       "i_sysstatvfs"
5529           From i_sysstatvfs.U:
5530
5531           This variable conditionally defines the "I_SYSSTATVFS" symbol, and
5532           indicates whether a C program should include <sys/statvfs.h>.
5533
5534       "i_systime"
5535           From i_time.U:
5536
5537           This variable conditionally defines "I_SYS_TIME", which indicates
5538           to the C program that it should include <sys/time.h>.
5539
5540       "i_systimek"
5541           From i_time.U:
5542
5543           This variable conditionally defines "I_SYS_TIME_KERNEL", which
5544           indicates to the C program that it should include <sys/time.h> with
5545           "KERNEL" defined.
5546
5547       "i_systimes"
5548           From i_systimes.U:
5549
5550           This variable conditionally defines the "I_SYS_TIMES" symbol, and
5551           indicates whether a C program should include <sys/times.h>.
5552
5553       "i_systypes"
5554           From i_systypes.U:
5555
5556           This variable conditionally defines the "I_SYS_TYPES" symbol, and
5557           indicates whether a C program should include <sys/types.h>.
5558
5559       "i_sysuio"
5560           From i_sysuio.U:
5561
5562           This variable conditionally defines the "I_SYSUIO" symbol, and
5563           indicates whether a C program should include <sys/uio.h>.
5564
5565       "i_sysun"
5566           From i_sysun.U:
5567
5568           This variable conditionally defines "I_SYS_UN", which indicates to
5569           the C program that it should include <sys/un.h> to get "UNIX"
5570           domain socket definitions.
5571
5572       "i_sysutsname"
5573           From i_sysutsname.U:
5574
5575           This variable conditionally defines the "I_SYSUTSNAME" symbol, and
5576           indicates whether a C program should include <sys/utsname.h>.
5577
5578       "i_sysvfs"
5579           From i_sysvfs.U:
5580
5581           This variable conditionally defines the "I_SYSVFS" symbol, and
5582           indicates whether a C program should include <sys/vfs.h>.
5583
5584       "i_syswait"
5585           From i_syswait.U:
5586
5587           This variable conditionally defines "I_SYS_WAIT", which indicates
5588           to the C program that it should include <sys/wait.h>.
5589
5590       "i_termio"
5591           From i_termio.U:
5592
5593           This variable conditionally defines the "I_TERMIO" symbol, which
5594           indicates to the C program that it should include <termio.h> rather
5595           than <sgtty.h>.
5596
5597       "i_termios"
5598           From i_termio.U:
5599
5600           This variable conditionally defines the "I_TERMIOS" symbol, which
5601           indicates to the C program that the "POSIX" <termios.h> file is to
5602           be included.
5603
5604       "i_time"
5605           From i_time.U:
5606
5607           This variable conditionally defines "I_TIME", which indicates to
5608           the C program that it should include <time.h>.
5609
5610       "i_unistd"
5611           From i_unistd.U:
5612
5613           This variable conditionally defines the "I_UNISTD" symbol, and
5614           indicates whether a C program should include <unistd.h>.
5615
5616       "i_ustat"
5617           From i_ustat.U:
5618
5619           This variable conditionally defines the "I_USTAT" symbol, and
5620           indicates whether a C program should include <ustat.h>.
5621
5622       "i_utime"
5623           From i_utime.U:
5624
5625           This variable conditionally defines the "I_UTIME" symbol, and
5626           indicates whether a C program should include <utime.h>.
5627
5628       "i_values"
5629           From i_values.U:
5630
5631           This variable conditionally defines the "I_VALUES" symbol, and
5632           indicates whether a C program may include <values.h> to get symbols
5633           like "MAXLONG" and friends.
5634
5635       "i_varargs"
5636           From i_varhdr.U:
5637
5638           This variable conditionally defines "I_VARARGS", which indicates to
5639           the C program that it should include <varargs.h>.
5640
5641       "i_varhdr"
5642           From i_varhdr.U:
5643
5644           Contains the name of the header to be included to get va_dcl
5645           definition.  Typically one of varargs.h or stdarg.h.
5646
5647       "i_vfork"
5648           From i_vfork.U:
5649
5650           This variable conditionally defines the "I_VFORK" symbol, and
5651           indicates whether a C program should include vfork.h.
5652
5653       "i_xlocale"
5654           From d_newlocale.U:
5655
5656           This symbol, if defined, indicates to the C program that it should
5657           include <xlocale.h> to get uselocale() and its friends
5658
5659       "ignore_versioned_solibs"
5660           From libs.U:
5661
5662           This variable should be non-empty if non-versioned shared libraries
5663           (libfoo.so.x.y) are to be ignored (because they cannot be linked
5664           against).
5665
5666       "inc_version_list"
5667           From inc_version_list.U:
5668
5669           This variable specifies the list of subdirectories in over which
5670           perl.c:incpush() and lib/lib.pm will automatically search when
5671           adding directories to @"INC".  The elements in the list are
5672           separated by spaces.  This is only useful if you have a perl
5673           library directory tree structured like the default one.  See
5674           "INSTALL" for how this works.  The versioned site_perl directory
5675           was introduced in 5.005, so that is the lowest possible value.
5676
5677           This list includes architecture-dependent directories back to
5678           version $api_versionstring (e.g. 5.5.640) and architecture-
5679           independent directories all the way back to 5.005.
5680
5681       "inc_version_list_init"
5682           From inc_version_list.U:
5683
5684           This variable holds the same list as inc_version_list, but each
5685           item is enclosed in double quotes and separated by commas, suitable
5686           for use in the "PERL_INC_VERSION_LIST" initialization.
5687
5688       "incpath"
5689           From usrinc.U:
5690
5691           This variable must precede the normal include path to get the right
5692           one, as in $incpath/usr/include or $incpath/usr/lib.  Value can be
5693           "" or /bsd43 on mips.
5694
5695       "incpth"
5696           From libpth.U:
5697
5698           This variable must precede the normal include path to get the right
5699           one, as in $incpath/usr/include or $incpath/usr/lib.  Value can be
5700           "" or /bsd43 on mips.
5701
5702       "inews"
5703           From Loc.U:
5704
5705           This variable is defined but not used by Configure.  The value is
5706           the empty string and is not useful.
5707
5708       "initialinstalllocation"
5709           From bin.U:
5710
5711           When userelocatableinc is true, this variable holds the location
5712           that make install should copy the perl binary to, with all the run-
5713           time relocatable paths calculated from this at install time.  When
5714           used, it is initialized to the original value of binexp, and then
5715           binexp is set to .../, as the other binaries are found relative to
5716           the perl binary.
5717
5718       "installarchlib"
5719           From archlib.U:
5720
5721           This variable is really the same as archlibexp but may differ on
5722           those systems using "AFS". For extra portability, only this
5723           variable should be used in makefiles.
5724
5725       "installbin"
5726           From bin.U:
5727
5728           This variable is the same as binexp unless "AFS" is running in
5729           which case the user is explicitly prompted for it. This variable
5730           should always be used in your makefiles for maximum portability.
5731
5732       "installhtml1dir"
5733           From html1dir.U:
5734
5735           This variable is really the same as html1direxp, unless you are
5736           using a different installprefix.  For extra portability, you should
5737           only use this variable within your makefiles.
5738
5739       "installhtml3dir"
5740           From html3dir.U:
5741
5742           This variable is really the same as html3direxp, unless you are
5743           using a different installprefix.  For extra portability, you should
5744           only use this variable within your makefiles.
5745
5746       "installman1dir"
5747           From man1dir.U:
5748
5749           This variable is really the same as man1direxp, unless you are
5750           using "AFS" in which case it points to the read/write location
5751           whereas man1direxp only points to the read-only access location.
5752           For extra portability, you should only use this variable within
5753           your makefiles.
5754
5755       "installman3dir"
5756           From man3dir.U:
5757
5758           This variable is really the same as man3direxp, unless you are
5759           using "AFS" in which case it points to the read/write location
5760           whereas man3direxp only points to the read-only access location.
5761           For extra portability, you should only use this variable within
5762           your makefiles.
5763
5764       "installprefix"
5765           From installprefix.U:
5766
5767           This variable holds the name of the directory below which "make
5768           install" will install the package.  For most users, this is the
5769           same as prefix.  However, it is useful for installing the software
5770           into a different (usually temporary) location after which it can be
5771           bundled up and moved somehow to the final location specified by
5772           prefix.
5773
5774       "installprefixexp"
5775           From installprefix.U:
5776
5777           This variable holds the full absolute path of installprefix with
5778           all ~-expansion done.
5779
5780       "installprivlib"
5781           From privlib.U:
5782
5783           This variable is really the same as privlibexp but may differ on
5784           those systems using "AFS". For extra portability, only this
5785           variable should be used in makefiles.
5786
5787       "installscript"
5788           From scriptdir.U:
5789
5790           This variable is usually the same as scriptdirexp, unless you are
5791           on a system running "AFS", in which case they may differ slightly.
5792           You should always use this variable within your makefiles for
5793           portability.
5794
5795       "installsitearch"
5796           From sitearch.U:
5797
5798           This variable is really the same as sitearchexp but may differ on
5799           those systems using "AFS". For extra portability, only this
5800           variable should be used in makefiles.
5801
5802       "installsitebin"
5803           From sitebin.U:
5804
5805           This variable is usually the same as sitebinexp, unless you are on
5806           a system running "AFS", in which case they may differ slightly. You
5807           should always use this variable within your makefiles for
5808           portability.
5809
5810       "installsitehtml1dir"
5811           From sitehtml1dir.U:
5812
5813           This variable is really the same as sitehtml1direxp, unless you are
5814           using "AFS" in which case it points to the read/write location
5815           whereas html1direxp only points to the read-only access location.
5816           For extra portability, you should only use this variable within
5817           your makefiles.
5818
5819       "installsitehtml3dir"
5820           From sitehtml3dir.U:
5821
5822           This variable is really the same as sitehtml3direxp, unless you are
5823           using "AFS" in which case it points to the read/write location
5824           whereas html3direxp only points to the read-only access location.
5825           For extra portability, you should only use this variable within
5826           your makefiles.
5827
5828       "installsitelib"
5829           From sitelib.U:
5830
5831           This variable is really the same as sitelibexp but may differ on
5832           those systems using "AFS". For extra portability, only this
5833           variable should be used in makefiles.
5834
5835       "installsiteman1dir"
5836           From siteman1dir.U:
5837
5838           This variable is really the same as siteman1direxp, unless you are
5839           using "AFS" in which case it points to the read/write location
5840           whereas man1direxp only points to the read-only access location.
5841           For extra portability, you should only use this variable within
5842           your makefiles.
5843
5844       "installsiteman3dir"
5845           From siteman3dir.U:
5846
5847           This variable is really the same as siteman3direxp, unless you are
5848           using "AFS" in which case it points to the read/write location
5849           whereas man3direxp only points to the read-only access location.
5850           For extra portability, you should only use this variable within
5851           your makefiles.
5852
5853       "installsitescript"
5854           From sitescript.U:
5855
5856           This variable is usually the same as sitescriptexp, unless you are
5857           on a system running "AFS", in which case they may differ slightly.
5858           You should always use this variable within your makefiles for
5859           portability.
5860
5861       "installstyle"
5862           From installstyle.U:
5863
5864           This variable describes the "style" of the perl installation.  This
5865           is intended to be useful for tools that need to manipulate entire
5866           perl distributions.  Perl itself doesn't use this to find its
5867           libraries -- the library directories are stored directly in
5868           Config.pm.  Currently, there are only two styles:  "lib" and
5869           lib/perl5.  The default library locations (e.g. privlib, sitelib)
5870           are either $prefix/lib or $prefix/lib/perl5.  The former is useful
5871           if $prefix is a directory dedicated to perl (e.g. /opt/perl), while
5872           the latter is useful if $prefix is shared by many packages, e.g. if
5873           $prefix=/usr/local.
5874
5875           Unfortunately, while this "style" variable is used to set defaults
5876           for all three directory hierarchies (core, vendor, and site), there
5877           is no guarantee that the same style is actually appropriate for all
5878           those directories.  For example, $prefix might be /opt/perl, but
5879           $siteprefix might be /usr/local.  (Perhaps, in retrospect, the
5880           "lib" style should never have been supported, but it did seem like
5881           a nice idea at the time.)
5882
5883           The situation is even less clear for tools such as MakeMaker that
5884           can be used to install additional modules into non-standard places.
5885           For example, if a user intends to install a module into a private
5886           directory (perhaps by setting "PREFIX" on the Makefile.PL command
5887           line), then there is no reason to assume that the Configure-time
5888           $installstyle setting will be relevant for that "PREFIX".
5889
5890           This may later be extended to include other information, so be
5891           careful with pattern-matching on the results.
5892
5893           For compatibility with perl5.005 and earlier, the default setting
5894           is based on whether or not $prefix contains the string "perl".
5895
5896       "installusrbinperl"
5897           From instubperl.U:
5898
5899           This variable tells whether Perl should be installed also as
5900           /usr/bin/perl in addition to $installbin/perl
5901
5902       "installvendorarch"
5903           From vendorarch.U:
5904
5905           This variable is really the same as vendorarchexp but may differ on
5906           those systems using "AFS". For extra portability, only this
5907           variable should be used in makefiles.
5908
5909       "installvendorbin"
5910           From vendorbin.U:
5911
5912           This variable is really the same as vendorbinexp but may differ on
5913           those systems using "AFS". For extra portability, only this
5914           variable should be used in makefiles.
5915
5916       "installvendorhtml1dir"
5917           From vendorhtml1dir.U:
5918
5919           This variable is really the same as vendorhtml1direxp but may
5920           differ on those systems using "AFS". For extra portability, only
5921           this variable should be used in makefiles.
5922
5923       "installvendorhtml3dir"
5924           From vendorhtml3dir.U:
5925
5926           This variable is really the same as vendorhtml3direxp but may
5927           differ on those systems using "AFS". For extra portability, only
5928           this variable should be used in makefiles.
5929
5930       "installvendorlib"
5931           From vendorlib.U:
5932
5933           This variable is really the same as vendorlibexp but may differ on
5934           those systems using "AFS". For extra portability, only this
5935           variable should be used in makefiles.
5936
5937       "installvendorman1dir"
5938           From vendorman1dir.U:
5939
5940           This variable is really the same as vendorman1direxp but may differ
5941           on those systems using "AFS". For extra portability, only this
5942           variable should be used in makefiles.
5943
5944       "installvendorman3dir"
5945           From vendorman3dir.U:
5946
5947           This variable is really the same as vendorman3direxp but may differ
5948           on those systems using "AFS". For extra portability, only this
5949           variable should be used in makefiles.
5950
5951       "installvendorscript"
5952           From vendorscript.U:
5953
5954           This variable is really the same as vendorscriptexp but may differ
5955           on those systems using "AFS". For extra portability, only this
5956           variable should be used in makefiles.
5957
5958       "intsize"
5959           From intsize.U:
5960
5961           This variable contains the value of the "INTSIZE" symbol, which
5962           indicates to the C program how many bytes there are in an int.
5963
5964       "issymlink"
5965           From issymlink.U:
5966
5967           This variable holds the test command to test for a symbolic link
5968           (if they are supported).  Typical values include "test -h" and
5969           "test -L".
5970
5971       "ivdformat"
5972           From perlxvf.U:
5973
5974           This variable contains the format string used for printing a Perl
5975           "IV" as a signed decimal integer.
5976
5977       "ivsize"
5978           From perlxv.U:
5979
5980           This variable is the size of an "IV" in bytes.
5981
5982       "ivtype"
5983           From perlxv.U:
5984
5985           This variable contains the C type used for Perl's "IV".
5986
5987   k
5988       "known_extensions"
5989           From Extensions.U:
5990
5991           This variable holds a list of all extensions (both "XS" and non-xs)
5992           included in the package source distribution.  This information is
5993           only really of use during the Perl build, as the list makes no
5994           distinction between extensions which were build and installed, and
5995           those which where not.  See "extensions" for the list of extensions
5996           actually built and available.
5997
5998       "ksh"
5999           From Loc.U:
6000
6001           This variable is defined but not used by Configure.  The value is
6002           the empty string and is not useful.
6003
6004   l
6005       "ld"
6006           From dlsrc.U:
6007
6008           This variable indicates the program to be used to link libraries
6009           for dynamic loading.  On some systems, it is "ld".  On "ELF"
6010           systems, it should be $cc.  Mostly, we'll try to respect the hint
6011           file setting.
6012
6013       "ld_can_script"
6014           From dlsrc.U:
6015
6016           This variable shows if the loader accepts scripts in the form of
6017           -Wl,--version-script=ld.script. This is currently only supported
6018           for "GNU" ld on "ELF" in dynamic loading builds.
6019
6020       "lddlflags"
6021           From dlsrc.U:
6022
6023           This variable contains any special flags that might need to be
6024           passed to $ld to create a shared library suitable for dynamic
6025           loading.  It is up to the makefile to use it.  For hpux, it should
6026           be "-b".  For sunos 4.1, it is empty.
6027
6028       "ldflags"
6029           From ccflags.U:
6030
6031           This variable contains any additional C loader flags desired by the
6032           user.  It is up to the Makefile to use this.
6033
6034       "ldflags_uselargefiles"
6035           From uselfs.U:
6036
6037           This variable contains the loader flags needed by large file builds
6038           and added to ldflags by hints files.
6039
6040       "ldlibpthname"
6041           From libperl.U:
6042
6043           This variable holds the name of the shared library search path,
6044           often "LD_LIBRARY_PATH".  To get an empty string, the hints file
6045           must set this to "none".
6046
6047       "less"
6048           From Loc.U:
6049
6050           This variable is used internally by Configure to determine the full
6051           pathname (if any) of the less program.  After Configure runs, the
6052           value is reset to a plain "less" and is not useful.
6053
6054       "lib_ext"
6055           From Unix.U:
6056
6057           This is an old synonym for _a.
6058
6059       "libc"
6060           From libc.U:
6061
6062           This variable contains the location of the C library.
6063
6064       "libperl"
6065           From libperl.U:
6066
6067           The perl executable is obtained by linking perlmain.c with libperl,
6068           any static extensions (usually just DynaLoader), and any other
6069           libraries needed on this system.  libperl is usually libperl.a, but
6070           can also be libperl.so.xxx if the user wishes to build a perl
6071           executable with a shared library.
6072
6073       "libpth"
6074           From libpth.U:
6075
6076           This variable holds the general path (space-separated) used to find
6077           libraries. It is intended to be used by other units.
6078
6079       "libs"
6080           From libs.U:
6081
6082           This variable holds the additional libraries we want to use.  It is
6083           up to the Makefile to deal with it.  The list can be empty.
6084
6085       "libsdirs"
6086           From libs.U:
6087
6088           This variable holds the directory names aka dirnames of the
6089           libraries we found and accepted, duplicates are removed.
6090
6091       "libsfiles"
6092           From libs.U:
6093
6094           This variable holds the filenames aka basenames of the libraries we
6095           found and accepted.
6096
6097       "libsfound"
6098           From libs.U:
6099
6100           This variable holds the full pathnames of the libraries we found
6101           and accepted.
6102
6103       "libspath"
6104           From libs.U:
6105
6106           This variable holds the directory names probed for libraries.
6107
6108       "libswanted"
6109           From Myinit.U:
6110
6111           This variable holds a list of all the libraries we want to search.
6112           The order is chosen to pick up the c library ahead of ucb or bsd
6113           libraries for SVR4.
6114
6115       "libswanted_uselargefiles"
6116           From uselfs.U:
6117
6118           This variable contains the libraries needed by large file builds
6119           and added to ldflags by hints files.  It is a space separated list
6120           of the library names without the "lib" prefix or any suffix, just
6121           like libswanted..
6122
6123       "line"
6124           From Loc.U:
6125
6126           This variable is defined but not used by Configure.  The value is
6127           the empty string and is not useful.
6128
6129       "lint"
6130           From Loc.U:
6131
6132           This variable is defined but not used by Configure.  The value is
6133           the empty string and is not useful.
6134
6135       "lkflags"
6136           From ccflags.U:
6137
6138           This variable contains any additional C partial linker flags
6139           desired by the user.  It is up to the Makefile to use this.
6140
6141       "ln"
6142           From Loc.U:
6143
6144           This variable is used internally by Configure to determine the full
6145           pathname (if any) of the ln program.  After Configure runs, the
6146           value is reset to a plain "ln" and is not useful.
6147
6148       "lns"
6149           From lns.U:
6150
6151           This variable holds the name of the command to make symbolic links
6152           (if they are supported).  It can be used in the Makefile. It is
6153           either "ln -s" or "ln"
6154
6155       "localtime_r_proto"
6156           From d_localtime_r.U:
6157
6158           This variable encodes the prototype of localtime_r.  It is zero if
6159           d_localtime_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
6160           macros of reentr.h if d_localtime_r is defined.
6161
6162       "locincpth"
6163           From ccflags.U:
6164
6165           This variable contains a list of additional directories to be
6166           searched by the compiler.  The appropriate "-I" directives will be
6167           added to ccflags.  This is intended to simplify setting local
6168           directories from the Configure command line.  It's not much, but it
6169           parallels the loclibpth stuff in libpth.U.
6170
6171       "loclibpth"
6172           From libpth.U:
6173
6174           This variable holds the paths (space-separated) used to find local
6175           libraries.  It is prepended to libpth, and is intended to be easily
6176           set from the command line.
6177
6178       "longdblinfbytes"
6179           From infnan.U:
6180
6181           This variable contains comma-separated list of hexadecimal bytes
6182           for the long double precision infinity.
6183
6184       "longdblkind"
6185           From d_longdbl.U:
6186
6187           This variable, if defined, encodes the type of a long double: 0 =
6188           double, 1 = "IEEE" 754 128-bit little endian, 2 = "IEEE" 754
6189           128-bit big endian, 3 = x86 80-bit little endian, 4 = x86 80-bit
6190           big endian, 5 = double-double 128-bit little endian, 6 = double-
6191           double 128-bit big endian, 7 = 128-bit mixed-endian double-double
6192           (64-bit LEs in "BE"), 8 = 128-bit mixed-endian double-double
6193           (64-bit BEs in "LE"), 9 = 128-bit "PDP"-style mixed-endian long
6194           doubles, -1 = unknown format.
6195
6196       "longdblmantbits"
6197           From mantbits.U:
6198
6199           This symbol, if defined, tells how many mantissa bits there are in
6200           long double precision floating point format.  Note that this can be
6201           "LDBL_MANT_DIG" minus one, since "LDBL_MANT_DIG" can include the
6202           "IEEE" 754 implicit bit.  The common x86-style 80-bit long double
6203           does not have an implicit bit.
6204
6205       "longdblnanbytes"
6206           From infnan.U:
6207
6208           This variable contains comma-separated list of hexadecimal bytes
6209           for the long double precision not-a-number.
6210
6211       "longdblsize"
6212           From d_longdbl.U:
6213
6214           This variable contains the value of the "LONG_DOUBLESIZE" symbol,
6215           which indicates to the C program how many bytes there are in a long
6216           double, if this system supports long doubles.  Note that this is
6217           sizeof(long double), which may include unused bytes.
6218
6219       "longlongsize"
6220           From d_longlong.U:
6221
6222           This variable contains the value of the "LONGLONGSIZE" symbol,
6223           which indicates to the C program how many bytes there are in a long
6224           long, if this system supports long long.
6225
6226       "longsize"
6227           From intsize.U:
6228
6229           This variable contains the value of the "LONGSIZE" symbol, which
6230           indicates to the C program how many bytes there are in a long.
6231
6232       "lp"
6233           From Loc.U:
6234
6235           This variable is defined but not used by Configure.  The value is
6236           the empty string and is not useful.
6237
6238       "lpr"
6239           From Loc.U:
6240
6241           This variable is defined but not used by Configure.  The value is
6242           the empty string and is not useful.
6243
6244       "ls"
6245           From Loc.U:
6246
6247           This variable is used internally by Configure to determine the full
6248           pathname (if any) of the ls program.  After Configure runs, the
6249           value is reset to a plain "ls" and is not useful.
6250
6251       "lseeksize"
6252           From lseektype.U:
6253
6254           This variable defines lseektype to be something like off_t, long,
6255           or whatever type is used to declare lseek offset's type in the
6256           kernel (which also appears to be lseek's return type).
6257
6258       "lseektype"
6259           From lseektype.U:
6260
6261           This variable defines lseektype to be something like off_t, long,
6262           or whatever type is used to declare lseek offset's type in the
6263           kernel (which also appears to be lseek's return type).
6264
6265   m
6266       "mail"
6267           From Loc.U:
6268
6269           This variable is defined but not used by Configure.  The value is
6270           the empty string and is not useful.
6271
6272       "mailx"
6273           From Loc.U:
6274
6275           This variable is defined but not used by Configure.  The value is
6276           the empty string and is not useful.
6277
6278       "make"
6279           From Loc.U:
6280
6281           This variable is used internally by Configure to determine the full
6282           pathname (if any) of the make program.  After Configure runs, the
6283           value is reset to a plain "make" and is not useful.
6284
6285       "make_set_make"
6286           From make.U:
6287
6288           Some versions of "make" set the variable "MAKE".  Others do not.
6289           This variable contains the string to be included in Makefile.SH so
6290           that "MAKE" is set if needed, and not if not needed.  Possible
6291           values are:
6292
6293           make_set_make="#"        # If your make program handles this for
6294           you,
6295
6296           make_set_make="MAKE=$make"    # if it doesn't.
6297
6298           This uses a comment character so that we can distinguish a "set"
6299           value (from a previous config.sh or Configure "-D" option) from an
6300           uncomputed value.
6301
6302       "mallocobj"
6303           From mallocsrc.U:
6304
6305           This variable contains the name of the malloc.o that this package
6306           generates, if that malloc.o is preferred over the system malloc.
6307           Otherwise the value is null.  This variable is intended for
6308           generating Makefiles.  See mallocsrc.
6309
6310       "mallocsrc"
6311           From mallocsrc.U:
6312
6313           This variable contains the name of the malloc.c that comes with the
6314           package, if that malloc.c is preferred over the system malloc.
6315           Otherwise the value is null.  This variable is intended for
6316           generating Makefiles.
6317
6318       "malloctype"
6319           From mallocsrc.U:
6320
6321           This variable contains the kind of ptr returned by malloc and
6322           realloc.
6323
6324       "man1dir"
6325           From man1dir.U:
6326
6327           This variable contains the name of the directory in which manual
6328           source pages are to be put.  It is the responsibility of the
6329           Makefile.SH to get the value of this into the proper command.  You
6330           must be prepared to do the ~name expansion yourself.
6331
6332       "man1direxp"
6333           From man1dir.U:
6334
6335           This variable is the same as the man1dir variable, but is filename
6336           expanded at configuration time, for convenient use in makefiles.
6337
6338       "man1ext"
6339           From man1dir.U:
6340
6341           This variable contains the extension that the manual page should
6342           have: one of "n", "l", or 1.  The Makefile must supply the ..  See
6343           man1dir.
6344
6345       "man3dir"
6346           From man3dir.U:
6347
6348           This variable contains the name of the directory in which manual
6349           source pages are to be put.  It is the responsibility of the
6350           Makefile.SH to get the value of this into the proper command.  You
6351           must be prepared to do the ~name expansion yourself.
6352
6353       "man3direxp"
6354           From man3dir.U:
6355
6356           This variable is the same as the man3dir variable, but is filename
6357           expanded at configuration time, for convenient use in makefiles.
6358
6359       "man3ext"
6360           From man3dir.U:
6361
6362           This variable contains the extension that the manual page should
6363           have: one of "n", "l", or 3.  The Makefile must supply the ..  See
6364           man3dir.
6365
6366       "mips_type"
6367           From usrinc.U:
6368
6369           This variable holds the environment type for the mips system.
6370           Possible values are "BSD 4.3" and "System V".
6371
6372       "mistrustnm"
6373           From Csym.U:
6374
6375           This variable can be used to establish a fallthrough for the cases
6376           where nm fails to find a symbol.  If usenm is false or usenm is
6377           true and mistrustnm is false, this variable has no effect.  If
6378           usenm is true and mistrustnm is "compile", a test program will be
6379           compiled to try to find any symbol that can't be located via nm
6380           lookup.  If mistrustnm is "run", the test program will be run as
6381           well as being compiled.
6382
6383       "mkdir"
6384           From Loc.U:
6385
6386           This variable is used internally by Configure to determine the full
6387           pathname (if any) of the mkdir program.  After Configure runs, the
6388           value is reset to a plain "mkdir" and is not useful.
6389
6390       "mmaptype"
6391           From d_mmap.U:
6392
6393           This symbol contains the type of pointer returned by mmap() (and
6394           simultaneously the type of the first argument).  It can be "void *"
6395           or "caddr_t".
6396
6397       "modetype"
6398           From modetype.U:
6399
6400           This variable defines modetype to be something like mode_t, int,
6401           unsigned short, or whatever type is used to declare file modes for
6402           system calls.
6403
6404       "more"
6405           From Loc.U:
6406
6407           This variable is used internally by Configure to determine the full
6408           pathname (if any) of the more program.  After Configure runs, the
6409           value is reset to a plain "more" and is not useful.
6410
6411       "multiarch"
6412           From multiarch.U:
6413
6414           This variable conditionally defines the "MULTIARCH" symbol which
6415           signifies the presence of multiplatform files.  This is normally
6416           set by hints files.
6417
6418       "mv"
6419           From Loc.U:
6420
6421           This variable is defined but not used by Configure.  The value is
6422           the empty string and is not useful.
6423
6424       "myarchname"
6425           From archname.U:
6426
6427           This variable holds the architecture name computed by Configure in
6428           a previous run. It is not intended to be perused by any user and
6429           should never be set in a hint file.
6430
6431       "mydomain"
6432           From myhostname.U:
6433
6434           This variable contains the eventual value of the "MYDOMAIN" symbol,
6435           which is the domain of the host the program is going to run on.
6436           The domain must be appended to myhostname to form a complete host
6437           name.  The dot comes with mydomain, and need not be supplied by the
6438           program.
6439
6440       "myhostname"
6441           From myhostname.U:
6442
6443           This variable contains the eventual value of the "MYHOSTNAME"
6444           symbol, which is the name of the host the program is going to run
6445           on.  The domain is not kept with hostname, but must be gotten from
6446           mydomain.  The dot comes with mydomain, and need not be supplied by
6447           the program.
6448
6449       "myuname"
6450           From Oldconfig.U:
6451
6452           The output of "uname -a" if available, otherwise the hostname.  The
6453           whole thing is then lower-cased and slashes and single quotes are
6454           removed.
6455
6456   n
6457       "n" From n.U:
6458
6459           This variable contains the "-n" flag if that is what causes the
6460           echo command to suppress newline.  Otherwise it is null.  Correct
6461           usage is $echo $n "prompt for a question: $c".
6462
6463       "need_va_copy"
6464           From need_va_copy.U:
6465
6466           This symbol, if defined, indicates that the system stores the
6467           variable argument list datatype, va_list, in a format that cannot
6468           be copied by simple assignment, so that some other means must be
6469           used when copying is required.  As such systems vary in their
6470           provision (or non-provision) of copying mechanisms, handy.h defines
6471           a platform- "independent" macro, Perl_va_copy(src, dst), to do the
6472           job.
6473
6474       "netdb_hlen_type"
6475           From netdbtype.U:
6476
6477           This variable holds the type used for the 2nd argument to
6478           gethostbyaddr().  Usually, this is int or size_t or unsigned.  This
6479           is only useful if you have gethostbyaddr(), naturally.
6480
6481       "netdb_host_type"
6482           From netdbtype.U:
6483
6484           This variable holds the type used for the 1st argument to
6485           gethostbyaddr().  Usually, this is char * or void *,  possibly with
6486           or without a const prefix.  This is only useful if you have
6487           gethostbyaddr(), naturally.
6488
6489       "netdb_name_type"
6490           From netdbtype.U:
6491
6492           This variable holds the type used for the argument to
6493           gethostbyname().  Usually, this is char * or const char *.  This is
6494           only useful if you have gethostbyname(), naturally.
6495
6496       "netdb_net_type"
6497           From netdbtype.U:
6498
6499           This variable holds the type used for the 1st argument to
6500           getnetbyaddr().  Usually, this is int or long.  This is only useful
6501           if you have getnetbyaddr(), naturally.
6502
6503       "nm"
6504           From Loc.U:
6505
6506           This variable is used internally by Configure to determine the full
6507           pathname (if any) of the nm program.  After Configure runs, the
6508           value is reset to a plain "nm" and is not useful.
6509
6510       "nm_opt"
6511           From usenm.U:
6512
6513           This variable holds the options that may be necessary for nm.
6514
6515       "nm_so_opt"
6516           From usenm.U:
6517
6518           This variable holds the options that may be necessary for nm to
6519           work on a shared library but that can not be used on an archive
6520           library.  Currently, this is only used by Linux, where nm --dynamic
6521           is *required* to get symbols from an "ELF" library which has been
6522           stripped, but nm --dynamic is *fatal* on an archive library.  Maybe
6523           Linux should just always set usenm=false.
6524
6525       "nonxs_ext"
6526           From Extensions.U:
6527
6528           This variable holds a list of all non-xs extensions built and
6529           installed by the package.  By default, all non-xs extensions
6530           distributed will be built, with the exception of platform-specific
6531           extensions (currently only one "VMS" specific extension).
6532
6533       "nroff"
6534           From Loc.U:
6535
6536           This variable is used internally by Configure to determine the full
6537           pathname (if any) of the nroff program.  After Configure runs, the
6538           value is reset to a plain "nroff" and is not useful.
6539
6540       "nv_overflows_integers_at"
6541           From perlxv.U:
6542
6543           This variable gives the largest integer value that NVs can hold as
6544           a constant floating point expression.  If it could not be
6545           determined, it holds the value 0.
6546
6547       "nv_preserves_uv_bits"
6548           From perlxv.U:
6549
6550           This variable indicates how many of bits type uvtype a variable
6551           nvtype can preserve.
6552
6553       "nveformat"
6554           From perlxvf.U:
6555
6556           This variable contains the format string used for printing a Perl
6557           "NV" using %e-ish floating point format.
6558
6559       "nvEUformat"
6560           From perlxvf.U:
6561
6562           This variable contains the format string used for printing a Perl
6563           "NV" using %E-ish floating point format.
6564
6565       "nvfformat"
6566           From perlxvf.U:
6567
6568           This variable contains the format string used for printing a Perl
6569           "NV" using %f-ish floating point format.
6570
6571       "nvFUformat"
6572           From perlxvf.U:
6573
6574           This variable contains the format string used for printing a Perl
6575           "NV" using %F-ish floating point format.
6576
6577       "nvgformat"
6578           From perlxvf.U:
6579
6580           This variable contains the format string used for printing a Perl
6581           "NV" using %g-ish floating point format.
6582
6583       "nvGUformat"
6584           From perlxvf.U:
6585
6586           This variable contains the format string used for printing a Perl
6587           "NV" using %G-ish floating point format.
6588
6589       "nvmantbits"
6590           From mantbits.U:
6591
6592           This variable tells how many bits the mantissa of a Perl "NV" has,
6593           not including the possible implicit bit.
6594
6595       "nvsize"
6596           From perlxv.U:
6597
6598           This variable is the size of a Perl "NV" in bytes.  Note that some
6599           floating point formats have unused bytes.
6600
6601       "nvtype"
6602           From perlxv.U:
6603
6604           This variable contains the C type used for Perl's "NV".
6605
6606   o
6607       "o_nonblock"
6608           From nblock_io.U:
6609
6610           This variable bears the symbol value to be used during open() or
6611           fcntl() to turn on non-blocking I/O for a file descriptor. If you
6612           wish to switch between blocking and non-blocking, you may try
6613           ioctl("FIOSNBIO") instead, but that is only supported by some
6614           devices.
6615
6616       "obj_ext"
6617           From Unix.U:
6618
6619           This is an old synonym for _o.
6620
6621       "old_pthread_create_joinable"
6622           From d_pthrattrj.U:
6623
6624           This variable defines the constant to use for creating joinable
6625           (aka undetached) pthreads.  Unused if pthread.h defines
6626           "PTHREAD_CREATE_JOINABLE".  If used, possible values are
6627           "PTHREAD_CREATE_UNDETACHED" and "__UNDETACHED".
6628
6629       "optimize"
6630           From ccflags.U:
6631
6632           This variable contains any optimizer/debugger flag that should be
6633           used.  It is up to the Makefile to use it.
6634
6635       "orderlib"
6636           From orderlib.U:
6637
6638           This variable is "true" if the components of libraries must be
6639           ordered (with `lorder $* | tsort`) before placing them in an
6640           archive.  Set to "false" if ranlib or ar can generate random
6641           libraries.
6642
6643       "osname"
6644           From Oldconfig.U:
6645
6646           This variable contains the operating system name (e.g. sunos,
6647           solaris, hpux, etc.).  It can be useful later on for setting
6648           defaults.  Any spaces are replaced with underscores.  It is set to
6649           a null string if we can't figure it out.
6650
6651       "osvers"
6652           From Oldconfig.U:
6653
6654           This variable contains the operating system version (e.g.  4.1.3,
6655           5.2, etc.).  It is primarily used for helping select an appropriate
6656           hints file, but might be useful elsewhere for setting defaults.  It
6657           is set to '' if we can't figure it out.  We try to be flexible
6658           about how much of the version number to keep, e.g. if 4.1.1, 4.1.2,
6659           and 4.1.3 are essentially the same for this package, hints files
6660           might just be os_4.0 or os_4.1, etc., not keeping separate files
6661           for each little release.
6662
6663       "otherlibdirs"
6664           From otherlibdirs.U:
6665
6666           This variable contains a colon-separated set of paths for the perl
6667           binary to search for additional library files or modules.  These
6668           directories will be tacked to the end of @"INC".  Perl will
6669           automatically search below each path for version- and architecture-
6670           specific directories.  See inc_version_list for more details.  A
6671           value of " " means "none" and is used to preserve this value for
6672           the next run through Configure.
6673
6674   p
6675       "package"
6676           From package.U:
6677
6678           This variable contains the name of the package being constructed.
6679           It is primarily intended for the use of later Configure units.
6680
6681       "pager"
6682           From pager.U:
6683
6684           This variable contains the name of the preferred pager on the
6685           system.  Usual values are (the full pathnames of) more, less, pg,
6686           or cat.
6687
6688       "passcat"
6689           From nis.U:
6690
6691           This variable contains a command that produces the text of the
6692           /etc/passwd file.  This is normally "cat /etc/passwd", but can be
6693           "ypcat passwd" when "NIS" is used.  On some systems, such as os390,
6694           there may be no equivalent command, in which case this variable is
6695           unset.
6696
6697       "patchlevel"
6698           From patchlevel.U:
6699
6700           The patchlevel level of this package.  The value of patchlevel
6701           comes from the patchlevel.h file.  In a version number such as
6702           5.6.1, this is the 6.  In patchlevel.h, this is referred to as
6703           "PERL_VERSION".
6704
6705       "path_sep"
6706           From Unix.U:
6707
6708           This is an old synonym for p_ in Head.U, the character used to
6709           separate elements in the command shell search "PATH".
6710
6711       "perl"
6712           From Loc.U:
6713
6714           This variable is used internally by Configure to determine the full
6715           pathname (if any) of the perl program.  After Configure runs, the
6716           value is reset to a plain "perl" and is not useful.
6717
6718       "perl5"
6719           From perl5.U:
6720
6721           This variable contains the full path (if any) to a previously
6722           installed perl5.005 or later suitable for running the script to
6723           determine inc_version_list.
6724
6725   P
6726       "PERL_API_REVISION"
6727           From patchlevel.h:
6728
6729           This number describes the earliest compatible "PERL_REVISION" 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_SUBVERSION"
6736           From patchlevel.h:
6737
6738           This number describes the earliest compatible "PERL_SUBVERSION" 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_API_VERSION"
6745           From patchlevel.h:
6746
6747           This number describes the earliest compatible "PERL_VERSION" of
6748           Perl ("compatibility" here being defined as sufficient binary/"API"
6749           compatibility to run "XS" code built with the older version).
6750           Normally this does not change across maintenance releases.  Please
6751           read the comment in patchlevel.h.
6752
6753       "PERL_CONFIG_SH"
6754           From Oldsyms.U:
6755
6756           This is set to "true" in config.sh so that a shell script sourcing
6757           config.sh can tell if it has been sourced already.
6758
6759       "PERL_PATCHLEVEL"
6760           From Oldsyms.U:
6761
6762           This symbol reflects the patchlevel, if available. Will usually
6763           come from the .patch file, which is available when the perl source
6764           tree was fetched with rsync.
6765
6766       "perl_patchlevel"
6767           From patchlevel.U:
6768
6769           This is the Perl patch level, a numeric change identifier, as
6770           defined by whichever source code maintenance system is used to
6771           maintain the patches; currently Perforce.  It does not correlate
6772           with the Perl version numbers or the maintenance versus development
6773           dichotomy except by also being increasing.
6774
6775       "PERL_REVISION"
6776           From Oldsyms.U:
6777
6778           In a Perl version number such as 5.6.2, this is the 5.  This value
6779           is manually set in patchlevel.h
6780
6781       "perl_static_inline"
6782           From d_static_inline.U:
6783
6784           This variable defines the "PERL_STATIC_INLINE" symbol to the best-
6785           guess incantation to use for static inline functions.
6786           Possibilities include static inline       (c99) static __inline__
6787           (gcc -ansi) static __inline     ("MSVC") static _inline      (older
6788           "MSVC") static              (c89 compilers)
6789
6790       "PERL_SUBVERSION"
6791           From Oldsyms.U:
6792
6793           In a Perl version number such as 5.6.2, this is the 2.  Values
6794           greater than 50 represent potentially unstable development
6795           subversions.  This value is manually set in patchlevel.h
6796
6797       "PERL_VERSION"
6798           From Oldsyms.U:
6799
6800           In a Perl version number such as 5.6.2, this is the 6.  This value
6801           is manually set in patchlevel.h
6802
6803       "perladmin"
6804           From perladmin.U:
6805
6806           Electronic mail address of the perl5 administrator.
6807
6808       "perllibs"
6809           From End.U:
6810
6811           The list of libraries needed by Perl only (any libraries needed by
6812           extensions only will by dropped, if using dynamic loading).
6813
6814       "perlpath"
6815           From perlpath.U:
6816
6817           This variable contains the eventual value of the "PERLPATH" symbol,
6818           which contains the name of the perl interpreter to be used in shell
6819           scripts and in the "eval "exec"" idiom.  This variable is not
6820           necessarily the pathname of the file containing the perl
6821           interpreter; you must append the executable extension (_exe) if it
6822           is not already present.  Note that Perl code that runs during the
6823           Perl build process cannot reference this variable, as Perl may not
6824           have been installed, or even if installed, may be a different
6825           version of Perl.
6826
6827       "pg"
6828           From Loc.U:
6829
6830           This variable is used internally by Configure to determine the full
6831           pathname (if any) of the pg program.  After Configure runs, the
6832           value is reset to a plain "pg" and is not useful.
6833
6834       "phostname"
6835           From myhostname.U:
6836
6837           This variable contains the eventual value of the "PHOSTNAME"
6838           symbol, which is a command that can be fed to popen() to get the
6839           host name.  The program should probably not presume that the domain
6840           is or isn't there already.
6841
6842       "pidtype"
6843           From pidtype.U:
6844
6845           This variable defines "PIDTYPE" to be something like pid_t, int,
6846           ushort, or whatever type is used to declare process ids in the
6847           kernel.
6848
6849       "plibpth"
6850           From libpth.U:
6851
6852           Holds the private path used by Configure to find out the libraries.
6853           Its value is prepend to libpth. This variable takes care of special
6854           machines, like the mips.  Usually, it should be empty.
6855
6856       "pmake"
6857           From Loc.U:
6858
6859           This variable is defined but not used by Configure.  The value is
6860           the empty string and is not useful.
6861
6862       "pr"
6863           From Loc.U:
6864
6865           This variable is defined but not used by Configure.  The value is
6866           the empty string and is not useful.
6867
6868       "prefix"
6869           From prefix.U:
6870
6871           This variable holds the name of the directory below which the user
6872           will install the package.  Usually, this is /usr/local, and
6873           executables go in /usr/local/bin, library stuff in /usr/local/lib,
6874           man pages in /usr/local/man, etc.  It is only used to set defaults
6875           for things in bin.U, mansrc.U, privlib.U, or scriptdir.U.
6876
6877       "prefixexp"
6878           From prefix.U:
6879
6880           This variable holds the full absolute path of the directory below
6881           which the user will install the package.  Derived from prefix.
6882
6883       "privlib"
6884           From privlib.U:
6885
6886           This variable contains the eventual value of the "PRIVLIB" symbol,
6887           which is the name of the private library for this package.  It may
6888           have a ~ on the front. It is up to the makefile to eventually
6889           create this directory while performing installation (with ~
6890           substitution).
6891
6892       "privlibexp"
6893           From privlib.U:
6894
6895           This variable is the ~name expanded version of privlib, so that you
6896           may use it directly in Makefiles or shell scripts.
6897
6898       "procselfexe"
6899           From d_procselfexe.U:
6900
6901           If d_procselfexe is defined, $procselfexe is the filename of the
6902           symbolic link pointing to the absolute pathname of the executing
6903           program.
6904
6905       "prototype"
6906           From prototype.U:
6907
6908           This variable holds the eventual value of "CAN_PROTOTYPE", which
6909           indicates the C compiler can handle function prototypes.
6910
6911       "ptrsize"
6912           From ptrsize.U:
6913
6914           This variable contains the value of the "PTRSIZE" symbol, which
6915           indicates to the C program how many bytes there are in a pointer.
6916
6917   q
6918       "quadkind"
6919           From quadtype.U:
6920
6921           This variable, if defined, encodes the type of a quad: 1 = int, 2 =
6922           long, 3 = long long, 4 = int64_t.
6923
6924       "quadtype"
6925           From quadtype.U:
6926
6927           This variable defines Quad_t to be something like long, int, long
6928           long, int64_t, or whatever type is used for 64-bit integers.
6929
6930   r
6931       "randbits"
6932           From randfunc.U:
6933
6934           Indicates how many bits are produced by the function used to
6935           generate normalized random numbers.
6936
6937       "randfunc"
6938           From randfunc.U:
6939
6940           Indicates the name of the random number function to use.  Values
6941           include drand48, random, and rand. In C programs, the "Drand01"
6942           macro is defined to generate uniformly distributed random numbers
6943           over the range [0., 1.[ (see drand01 and nrand).
6944
6945       "random_r_proto"
6946           From d_random_r.U:
6947
6948           This variable encodes the prototype of random_r.  It is zero if
6949           d_random_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
6950           of reentr.h if d_random_r is defined.
6951
6952       "randseedtype"
6953           From randfunc.U:
6954
6955           Indicates the type of the argument of the seedfunc.
6956
6957       "ranlib"
6958           From orderlib.U:
6959
6960           This variable is set to the pathname of the ranlib program, if it
6961           is needed to generate random libraries.  Set to ":" if ar can
6962           generate random libraries or if random libraries are not supported
6963
6964       "rd_nodata"
6965           From nblock_io.U:
6966
6967           This variable holds the return code from read() when no data is
6968           present. It should be -1, but some systems return 0 when "O_NDELAY"
6969           is used, which is a shame because you cannot make the difference
6970           between no data and an EOF.. Sigh!
6971
6972       "readdir64_r_proto"
6973           From d_readdir64_r.U:
6974
6975           This variable encodes the prototype of readdir64_r.  It is zero if
6976           d_readdir64_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
6977           macros of reentr.h if d_readdir64_r is defined.
6978
6979       "readdir_r_proto"
6980           From d_readdir_r.U:
6981
6982           This variable encodes the prototype of readdir_r.  It is zero if
6983           d_readdir_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
6984           of reentr.h if d_readdir_r is defined.
6985
6986       "revision"
6987           From patchlevel.U:
6988
6989           The value of revision comes from the patchlevel.h file.  In a
6990           version number such as 5.6.1, this is the 5.  In patchlevel.h, this
6991           is referred to as "PERL_REVISION".
6992
6993       "rm"
6994           From Loc.U:
6995
6996           This variable is used internally by Configure to determine the full
6997           pathname (if any) of the rm program.  After Configure runs, the
6998           value is reset to a plain "rm" and is not useful.
6999
7000       "rm_try"
7001           From Unix.U:
7002
7003           This is a cleanup variable for try test programs.  Internal
7004           Configure use only.
7005
7006       "rmail"
7007           From Loc.U:
7008
7009           This variable is defined but not used by Configure.  The value is
7010           the empty string and is not useful.
7011
7012       "run"
7013           From Cross.U:
7014
7015           This variable contains the command used by Configure to copy and
7016           execute a cross-compiled executable in the target host.  Useful and
7017           available only during Perl build.  Empty string '' if not cross-
7018           compiling.
7019
7020       "runnm"
7021           From usenm.U:
7022
7023           This variable contains "true" or "false" depending whether the nm
7024           extraction should be performed or not, according to the value of
7025           usenm and the flags on the Configure command line.
7026
7027   s
7028       "sched_yield"
7029           From d_pthread_y.U:
7030
7031           This variable defines the way to yield the execution of the current
7032           thread.
7033
7034       "scriptdir"
7035           From scriptdir.U:
7036
7037           This variable holds the name of the directory in which the user
7038           wants to put publicly scripts for the package in question.  It is
7039           either the same directory as for binaries, or a special one that
7040           can be mounted across different architectures, like /usr/share.
7041           Programs must be prepared to deal with ~name expansion.
7042
7043       "scriptdirexp"
7044           From scriptdir.U:
7045
7046           This variable is the same as scriptdir, but is filename expanded at
7047           configuration time, for programs not wanting to bother with it.
7048
7049       "sed"
7050           From Loc.U:
7051
7052           This variable is used internally by Configure to determine the full
7053           pathname (if any) of the sed program.  After Configure runs, the
7054           value is reset to a plain "sed" and is not useful.
7055
7056       "seedfunc"
7057           From randfunc.U:
7058
7059           Indicates the random number generating seed function.  Values
7060           include srand48, srandom, and srand.
7061
7062       "selectminbits"
7063           From selectminbits.U:
7064
7065           This variable holds the minimum number of bits operated by select.
7066           That is, if you do select(n, ...), how many bits at least will be
7067           cleared in the masks if some activity is detected.  Usually this is
7068           either n or 32*ceil(n/32), especially many little-endians do the
7069           latter.  This is only useful if you have select(), naturally.
7070
7071       "selecttype"
7072           From selecttype.U:
7073
7074           This variable holds the type used for the 2nd, 3rd, and 4th
7075           arguments to select.  Usually, this is "fd_set *", if "HAS_FD_SET"
7076           is defined, and "int *" otherwise.  This is only useful if you have
7077           select(), naturally.
7078
7079       "sendmail"
7080           From Loc.U:
7081
7082           This variable is defined but not used by Configure.  The value is
7083           the empty string and is not useful.
7084
7085       "setgrent_r_proto"
7086           From d_setgrent_r.U:
7087
7088           This variable encodes the prototype of setgrent_r.  It is zero if
7089           d_setgrent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
7090           macros of reentr.h if d_setgrent_r is defined.
7091
7092       "sethostent_r_proto"
7093           From d_sethostent_r.U:
7094
7095           This variable encodes the prototype of sethostent_r.  It is zero if
7096           d_sethostent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
7097           macros of reentr.h if d_sethostent_r is defined.
7098
7099       "setlocale_r_proto"
7100           From d_setlocale_r.U:
7101
7102           This variable encodes the prototype of setlocale_r.  It is zero if
7103           d_setlocale_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
7104           macros of reentr.h if d_setlocale_r is defined.
7105
7106       "setnetent_r_proto"
7107           From d_setnetent_r.U:
7108
7109           This variable encodes the prototype of setnetent_r.  It is zero if
7110           d_setnetent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
7111           macros of reentr.h if d_setnetent_r is defined.
7112
7113       "setprotoent_r_proto"
7114           From d_setprotoent_r.U:
7115
7116           This variable encodes the prototype of setprotoent_r.  It is zero
7117           if d_setprotoent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
7118           macros of reentr.h if d_setprotoent_r is defined.
7119
7120       "setpwent_r_proto"
7121           From d_setpwent_r.U:
7122
7123           This variable encodes the prototype of setpwent_r.  It is zero if
7124           d_setpwent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
7125           macros of reentr.h if d_setpwent_r is defined.
7126
7127       "setservent_r_proto"
7128           From d_setservent_r.U:
7129
7130           This variable encodes the prototype of setservent_r.  It is zero if
7131           d_setservent_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
7132           macros of reentr.h if d_setservent_r is defined.
7133
7134       "sGMTIME_max"
7135           From time_size.U:
7136
7137           This variable defines the maximum value of the time_t offset that
7138           the system function gmtime () accepts
7139
7140       "sGMTIME_min"
7141           From time_size.U:
7142
7143           This variable defines the minimum value of the time_t offset that
7144           the system function gmtime () accepts
7145
7146       "sh"
7147           From sh.U:
7148
7149           This variable contains the full pathname of the shell used on this
7150           system to execute Bourne shell scripts.  Usually, this will be
7151           /bin/sh, though it's possible that some systems will have /bin/ksh,
7152           /bin/pdksh, /bin/ash, /bin/bash, or even something such as
7153           D:/bin/sh.exe.  This unit comes before Options.U, so you can't set
7154           sh with a "-D" option, though you can override this (and startsh)
7155           with "-O -Dsh=/bin/whatever -Dstartsh=whatever"
7156
7157       "shar"
7158           From Loc.U:
7159
7160           This variable is defined but not used by Configure.  The value is
7161           the empty string and is not useful.
7162
7163       "sharpbang"
7164           From spitshell.U:
7165
7166           This variable contains the string #! if this system supports that
7167           construct.
7168
7169       "shmattype"
7170           From d_shmat.U:
7171
7172           This symbol contains the type of pointer returned by shmat().  It
7173           can be "void *" or "char *".
7174
7175       "shortsize"
7176           From intsize.U:
7177
7178           This variable contains the value of the "SHORTSIZE" symbol which
7179           indicates to the C program how many bytes there are in a short.
7180
7181       "shrpenv"
7182           From libperl.U:
7183
7184           If the user builds a shared libperl.so, then we need to tell the
7185           "perl" executable where it will be able to find the installed
7186           libperl.so.  One way to do this on some systems is to set the
7187           environment variable "LD_RUN_PATH" to the directory that will be
7188           the final location of the shared libperl.so.  The makefile can use
7189           this with something like $shrpenv $("CC") -o perl perlmain.o
7190           $libperl $libs Typical values are shrpenv="env
7191           "LD_RUN_PATH"=$archlibexp/"CORE"" or shrpenv='' See the main perl
7192           Makefile.SH for actual working usage.  Alternatively, we might be
7193           able to use a command line option such as -R $archlibexp/"CORE"
7194           (Solaris) or -Wl,-rpath $archlibexp/"CORE" (Linux).
7195
7196       "shsharp"
7197           From spitshell.U:
7198
7199           This variable tells further Configure units whether your sh can
7200           handle # comments.
7201
7202       "sig_count"
7203           From sig_name.U:
7204
7205           This variable holds a number larger than the largest valid signal
7206           number.  This is usually the same as the "NSIG" macro.
7207
7208       "sig_name"
7209           From sig_name.U:
7210
7211           This variable holds the signal names, space separated. The leading
7212           "SIG" in signal name is removed.  A "ZERO" is prepended to the
7213           list.  This is currently not used, sig_name_init is used instead.
7214
7215       "sig_name_init"
7216           From sig_name.U:
7217
7218           This variable holds the signal names, enclosed in double quotes and
7219           separated by commas, suitable for use in the "SIG_NAME" definition
7220           below.  A "ZERO" is prepended to the list, and the list is
7221           terminated with a plain 0.  The leading "SIG" in signal names is
7222           removed. See sig_num.
7223
7224       "sig_num"
7225           From sig_name.U:
7226
7227           This variable holds the signal numbers, space separated. A "ZERO"
7228           is prepended to the list (corresponding to the fake "SIGZERO").
7229           Those numbers correspond to  the value of the signal listed in the
7230           same place within the sig_name list.  This is currently not used,
7231           sig_num_init is used instead.
7232
7233       "sig_num_init"
7234           From sig_name.U:
7235
7236           This variable holds the signal numbers, enclosed in double quotes
7237           and separated by commas, suitable for use in the "SIG_NUM"
7238           definition below.  A "ZERO" is prepended to the list, and the list
7239           is terminated with a plain 0.
7240
7241       "sig_size"
7242           From sig_name.U:
7243
7244           This variable contains the number of elements of the sig_name and
7245           sig_num arrays.
7246
7247       "signal_t"
7248           From d_voidsig.U:
7249
7250           This variable holds the type of the signal handler (void or int).
7251
7252       "sitearch"
7253           From sitearch.U:
7254
7255           This variable contains the eventual value of the "SITEARCH" symbol,
7256           which is the name of the private library for this package.  It may
7257           have a ~ on the front. It is up to the makefile to eventually
7258           create this directory while performing installation (with ~
7259           substitution).  The standard distribution will put nothing in this
7260           directory.  After perl has been installed, users may install their
7261           own local architecture-dependent modules in this directory with
7262           MakeMaker Makefile.PL or equivalent.  See "INSTALL" for details.
7263
7264       "sitearchexp"
7265           From sitearch.U:
7266
7267           This variable is the ~name expanded version of sitearch, so that
7268           you may use it directly in Makefiles or shell scripts.
7269
7270       "sitebin"
7271           From sitebin.U:
7272
7273           This variable holds the name of the directory in which the user
7274           wants to put add-on publicly executable files for the package in
7275           question.  It is most often a local directory such as
7276           /usr/local/bin. Programs using this variable must be prepared to
7277           deal with ~name substitution.  The standard distribution will put
7278           nothing in this directory.  After perl has been installed, users
7279           may install their own local executables in this directory with
7280           MakeMaker Makefile.PL or equivalent.  See "INSTALL" for details.
7281
7282       "sitebinexp"
7283           From sitebin.U:
7284
7285           This is the same as the sitebin variable, but is filename expanded
7286           at configuration time, for use in your makefiles.
7287
7288       "sitehtml1dir"
7289           From sitehtml1dir.U:
7290
7291           This variable contains the name of the directory in which site-
7292           specific html source pages are to be put.  It is the responsibility
7293           of the Makefile.SH to get the value of this into the proper
7294           command.  You must be prepared to do the ~name expansion yourself.
7295           The standard distribution will put nothing in this directory.
7296           After perl has been installed, users may install their own local
7297           html pages in this directory with MakeMaker Makefile.PL or
7298           equivalent.  See "INSTALL" for details.
7299
7300       "sitehtml1direxp"
7301           From sitehtml1dir.U:
7302
7303           This variable is the same as the sitehtml1dir variable, but is
7304           filename expanded at configuration time, for convenient use in
7305           makefiles.
7306
7307       "sitehtml3dir"
7308           From sitehtml3dir.U:
7309
7310           This variable contains the name of the directory in which site-
7311           specific library html source pages are to be put.  It is the
7312           responsibility of the Makefile.SH to get the value of this into the
7313           proper command.  You must be prepared to do the ~name expansion
7314           yourself.  The standard distribution will put nothing in this
7315           directory.  After perl has been installed, users may install their
7316           own local library html pages in this directory with MakeMaker
7317           Makefile.PL or equivalent.  See "INSTALL" for details.
7318
7319       "sitehtml3direxp"
7320           From sitehtml3dir.U:
7321
7322           This variable is the same as the sitehtml3dir variable, but is
7323           filename expanded at configuration time, for convenient use in
7324           makefiles.
7325
7326       "sitelib"
7327           From sitelib.U:
7328
7329           This variable contains the eventual value of the "SITELIB" symbol,
7330           which is the name of the private library for this package.  It may
7331           have a ~ on the front. It is up to the makefile to eventually
7332           create this directory while performing installation (with ~
7333           substitution).  The standard distribution will put nothing in this
7334           directory.  After perl has been installed, users may install their
7335           own local architecture-independent modules in this directory with
7336           MakeMaker Makefile.PL or equivalent.  See "INSTALL" for details.
7337
7338       "sitelib_stem"
7339           From sitelib.U:
7340
7341           This variable is $sitelibexp with any trailing version-specific
7342           component removed.  The elements in inc_version_list
7343           (inc_version_list.U) can be tacked onto this variable to generate a
7344           list of directories to search.
7345
7346       "sitelibexp"
7347           From sitelib.U:
7348
7349           This variable is the ~name expanded version of sitelib, so that you
7350           may use it directly in Makefiles or shell scripts.
7351
7352       "siteman1dir"
7353           From siteman1dir.U:
7354
7355           This variable contains the name of the directory in which site-
7356           specific manual source pages are to be put.  It is the
7357           responsibility of the Makefile.SH to get the value of this into the
7358           proper command.  You must be prepared to do the ~name expansion
7359           yourself.  The standard distribution will put nothing in this
7360           directory.  After perl has been installed, users may install their
7361           own local man1 pages in this directory with MakeMaker Makefile.PL
7362           or equivalent.  See "INSTALL" for details.
7363
7364       "siteman1direxp"
7365           From siteman1dir.U:
7366
7367           This variable is the same as the siteman1dir variable, but is
7368           filename expanded at configuration time, for convenient use in
7369           makefiles.
7370
7371       "siteman3dir"
7372           From siteman3dir.U:
7373
7374           This variable contains the name of the directory in which site-
7375           specific library man source pages are to be put.  It is the
7376           responsibility of the Makefile.SH to get the value of this into the
7377           proper command.  You must be prepared to do the ~name expansion
7378           yourself.  The standard distribution will put nothing in this
7379           directory.  After perl has been installed, users may install their
7380           own local man3 pages in this directory with MakeMaker Makefile.PL
7381           or equivalent.  See "INSTALL" for details.
7382
7383       "siteman3direxp"
7384           From siteman3dir.U:
7385
7386           This variable is the same as the siteman3dir variable, but is
7387           filename expanded at configuration time, for convenient use in
7388           makefiles.
7389
7390       "siteprefix"
7391           From siteprefix.U:
7392
7393           This variable holds the full absolute path of the directory below
7394           which the user will install add-on packages.  See "INSTALL" for
7395           usage and examples.
7396
7397       "siteprefixexp"
7398           From siteprefix.U:
7399
7400           This variable holds the full absolute path of the directory below
7401           which the user will install add-on packages.  Derived from
7402           siteprefix.
7403
7404       "sitescript"
7405           From sitescript.U:
7406
7407           This variable holds the name of the directory in which the user
7408           wants to put add-on publicly executable files for the package in
7409           question.  It is most often a local directory such as
7410           /usr/local/bin. Programs using this variable must be prepared to
7411           deal with ~name substitution.  The standard distribution will put
7412           nothing in this directory.  After perl has been installed, users
7413           may install their own local scripts in this directory with
7414           MakeMaker Makefile.PL or equivalent.  See "INSTALL" for details.
7415
7416       "sitescriptexp"
7417           From sitescript.U:
7418
7419           This is the same as the sitescript variable, but is filename
7420           expanded at configuration time, for use in your makefiles.
7421
7422       "sizesize"
7423           From sizesize.U:
7424
7425           This variable contains the size of a sizetype in bytes.
7426
7427       "sizetype"
7428           From sizetype.U:
7429
7430           This variable defines sizetype to be something like size_t,
7431           unsigned long, or whatever type is used to declare length
7432           parameters for string functions.
7433
7434       "sleep"
7435           From Loc.U:
7436
7437           This variable is defined but not used by Configure.  The value is
7438           the empty string and is not useful.
7439
7440       "sLOCALTIME_max"
7441           From time_size.U:
7442
7443           This variable defines the maximum value of the time_t offset that
7444           the system function localtime () accepts
7445
7446       "sLOCALTIME_min"
7447           From time_size.U:
7448
7449           This variable defines the minimum value of the time_t offset that
7450           the system function localtime () accepts
7451
7452       "smail"
7453           From Loc.U:
7454
7455           This variable is defined but not used by Configure.  The value is
7456           the empty string and is not useful.
7457
7458       "so"
7459           From so.U:
7460
7461           This variable holds the extension used to identify shared libraries
7462           (also known as shared objects) on the system. Usually set to "so".
7463
7464       "sockethdr"
7465           From d_socket.U:
7466
7467           This variable has any cpp "-I" flags needed for socket support.
7468
7469       "socketlib"
7470           From d_socket.U:
7471
7472           This variable has the names of any libraries needed for socket
7473           support.
7474
7475       "socksizetype"
7476           From socksizetype.U:
7477
7478           This variable holds the type used for the size argument for various
7479           socket calls like accept.  Usual values include socklen_t, size_t,
7480           and int.
7481
7482       "sort"
7483           From Loc.U:
7484
7485           This variable is used internally by Configure to determine the full
7486           pathname (if any) of the sort program.  After Configure runs, the
7487           value is reset to a plain "sort" and is not useful.
7488
7489       "spackage"
7490           From package.U:
7491
7492           This variable contains the name of the package being constructed,
7493           with the first letter uppercased, i.e. suitable for starting
7494           sentences.
7495
7496       "spitshell"
7497           From spitshell.U:
7498
7499           This variable contains the command necessary to spit out a runnable
7500           shell on this system.  It is either cat or a grep "-v" for #
7501           comments.
7502
7503       "sPRId64"
7504           From quadfio.U:
7505
7506           This variable, if defined, contains the string used by stdio to
7507           format 64-bit decimal numbers (format "d") for output.
7508
7509       "sPRIeldbl"
7510           From longdblfio.U:
7511
7512           This variable, if defined, contains the string used by stdio to
7513           format long doubles (format "e") for output.
7514
7515       "sPRIEUldbl"
7516           From longdblfio.U:
7517
7518           This variable, if defined, contains the string used by stdio to
7519           format long doubles (format "E") for output.  The "U" in the name
7520           is to separate this from sPRIeldbl so that even case-blind systems
7521           can see the difference.
7522
7523       "sPRIfldbl"
7524           From longdblfio.U:
7525
7526           This variable, if defined, contains the string used by stdio to
7527           format long doubles (format "f") for output.
7528
7529       "sPRIFUldbl"
7530           From longdblfio.U:
7531
7532           This variable, if defined, contains the string used by stdio to
7533           format long doubles (format "F") for output.  The "U" in the name
7534           is to separate this from sPRIfldbl so that even case-blind systems
7535           can see the difference.
7536
7537       "sPRIgldbl"
7538           From longdblfio.U:
7539
7540           This variable, if defined, contains the string used by stdio to
7541           format long doubles (format "g") for output.
7542
7543       "sPRIGUldbl"
7544           From longdblfio.U:
7545
7546           This variable, if defined, contains the string used by stdio to
7547           format long doubles (format "G") for output.  The "U" in the name
7548           is to separate this from sPRIgldbl so that even case-blind systems
7549           can see the difference.
7550
7551       "sPRIi64"
7552           From quadfio.U:
7553
7554           This variable, if defined, contains the string used by stdio to
7555           format 64-bit decimal numbers (format "i") for output.
7556
7557       "sPRIo64"
7558           From quadfio.U:
7559
7560           This variable, if defined, contains the string used by stdio to
7561           format 64-bit octal numbers (format "o") for output.
7562
7563       "sPRIu64"
7564           From quadfio.U:
7565
7566           This variable, if defined, contains the string used by stdio to
7567           format 64-bit unsigned decimal numbers (format "u") for output.
7568
7569       "sPRIx64"
7570           From quadfio.U:
7571
7572           This variable, if defined, contains the string used by stdio to
7573           format 64-bit hexadecimal numbers (format "x") for output.
7574
7575       "sPRIXU64"
7576           From quadfio.U:
7577
7578           This variable, if defined, contains the string used by stdio to
7579           format 64-bit hExADECimAl numbers (format "X") for output.  The "U"
7580           in the name is to separate this from sPRIx64 so that even case-
7581           blind systems can see the difference.
7582
7583       "srand48_r_proto"
7584           From d_srand48_r.U:
7585
7586           This variable encodes the prototype of srand48_r.  It is zero if
7587           d_srand48_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
7588           of reentr.h if d_srand48_r is defined.
7589
7590       "srandom_r_proto"
7591           From d_srandom_r.U:
7592
7593           This variable encodes the prototype of srandom_r.  It is zero if
7594           d_srandom_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
7595           of reentr.h if d_srandom_r is defined.
7596
7597       "src"
7598           From src.U:
7599
7600           This variable holds the (possibly relative) path of the package
7601           source.  It is up to the Makefile to use this variable and set
7602           "VPATH" accordingly to find the sources remotely.  Use $pkgsrc to
7603           have an absolute path.
7604
7605       "sSCNfldbl"
7606           From longdblfio.U:
7607
7608           This variable, if defined, contains the string used by stdio to
7609           format long doubles (format "f") for input.
7610
7611       "ssizetype"
7612           From ssizetype.U:
7613
7614           This variable defines ssizetype to be something like ssize_t, long
7615           or int.  It is used by functions that return a count of bytes or an
7616           error condition.  It must be a signed type.  We will pick a type
7617           such that sizeof(SSize_t) == sizeof(Size_t).
7618
7619       "st_ino_sign"
7620           From st_ino_def.U:
7621
7622           This variable contains the signedness of struct stat's st_ino.  1
7623           for unsigned, -1 for signed.
7624
7625       "st_ino_size"
7626           From st_ino_def.U:
7627
7628           This variable contains the size of struct stat's st_ino in bytes.
7629
7630       "startperl"
7631           From startperl.U:
7632
7633           This variable contains the string to put on the front of a perl
7634           script to make sure (hopefully) that it runs with perl and not some
7635           shell. Of course, that leading line must be followed by the
7636           classical perl idiom: eval 'exec perl -S $0 ${1+$@}' if
7637           $running_under_some_shell; to guarantee perl startup should the
7638           shell execute the script. Note that this magic incantation is not
7639           understood by csh.
7640
7641       "startsh"
7642           From startsh.U:
7643
7644           This variable contains the string to put on the front of a shell
7645           script to make sure (hopefully) that it runs with sh and not some
7646           other shell.
7647
7648       "static_ext"
7649           From Extensions.U:
7650
7651           This variable holds a list of "XS" extension files we want to link
7652           statically into the package.  It is used by Makefile.
7653
7654       "stdchar"
7655           From stdchar.U:
7656
7657           This variable conditionally defines "STDCHAR" to be the type of
7658           char used in stdio.h.  It has the values "unsigned char" or "char".
7659
7660       "stdio_base"
7661           From d_stdstdio.U:
7662
7663           This variable defines how, given a "FILE" pointer, fp, to access
7664           the _base field (or equivalent) of stdio.h's "FILE" structure.
7665           This will be used to define the macro FILE_base(fp).
7666
7667       "stdio_bufsiz"
7668           From d_stdstdio.U:
7669
7670           This variable defines how, given a "FILE" pointer, fp, to determine
7671           the number of bytes store in the I/O buffer pointer to by the _base
7672           field (or equivalent) of stdio.h's "FILE" structure.  This will be
7673           used to define the macro FILE_bufsiz(fp).
7674
7675       "stdio_cnt"
7676           From d_stdstdio.U:
7677
7678           This variable defines how, given a "FILE" pointer, fp, to access
7679           the _cnt field (or equivalent) of stdio.h's "FILE" structure.  This
7680           will be used to define the macro FILE_cnt(fp).
7681
7682       "stdio_filbuf"
7683           From d_stdstdio.U:
7684
7685           This variable defines how, given a "FILE" pointer, fp, to tell
7686           stdio to refill its internal buffers (?).  This will be used to
7687           define the macro FILE_filbuf(fp).
7688
7689       "stdio_ptr"
7690           From d_stdstdio.U:
7691
7692           This variable defines how, given a "FILE" pointer, fp, to access
7693           the _ptr field (or equivalent) of stdio.h's "FILE" structure.  This
7694           will be used to define the macro FILE_ptr(fp).
7695
7696       "stdio_stream_array"
7697           From stdio_streams.U:
7698
7699           This variable tells the name of the array holding the stdio
7700           streams.  Usual values include _iob, __iob, and __sF.
7701
7702       "strerror_r_proto"
7703           From d_strerror_r.U:
7704
7705           This variable encodes the prototype of strerror_r.  It is zero if
7706           d_strerror_r is undef, and one of the "REENTRANT_PROTO_T_ABC"
7707           macros of reentr.h if d_strerror_r is defined.
7708
7709       "strings"
7710           From i_string.U:
7711
7712           This variable holds the full path of the string header that will be
7713           used. Typically /usr/include/string.h or /usr/include/strings.h.
7714
7715       "submit"
7716           From Loc.U:
7717
7718           This variable is defined but not used by Configure.  The value is
7719           the empty string and is not useful.
7720
7721       "subversion"
7722           From patchlevel.U:
7723
7724           The subversion level of this package.  The value of subversion
7725           comes from the patchlevel.h file.  In a version number such as
7726           5.6.1, this is the 1.  In patchlevel.h, this is referred to as
7727           "PERL_SUBVERSION".  This is unique to perl.
7728
7729       "sysman"
7730           From sysman.U:
7731
7732           This variable holds the place where the manual is located on this
7733           system. It is not the place where the user wants to put his manual
7734           pages. Rather it is the place where Configure may look to find
7735           manual for unix commands (section 1 of the manual usually). See
7736           mansrc.
7737
7738       "sysroot"
7739           From Sysroot.U:
7740
7741           This variable is empty unless supplied by the Configure user.  It
7742           can contain a path to an alternative root directory, under which
7743           headers and libraries for the compilation target can be found. This
7744           is generally used when cross-compiling using a gcc-like compiler.
7745
7746   t
7747       "tail"
7748           From Loc.U:
7749
7750           This variable is defined but not used by Configure.  The value is
7751           the empty string and is not useful.
7752
7753       "tar"
7754           From Loc.U:
7755
7756           This variable is defined but not used by Configure.  The value is
7757           the empty string and is not useful.
7758
7759       "targetarch"
7760           From Cross.U:
7761
7762           If cross-compiling, this variable contains the target architecture.
7763           If not, this will be empty.
7764
7765       "targetdir"
7766           From Cross.U:
7767
7768           This variable contains a path that will be created on the target
7769           host using targetmkdir, and then used to copy the cross-compiled
7770           executables to. Defaults to /tmp if not set.
7771
7772       "targetenv"
7773           From Cross.U:
7774
7775           If cross-compiling, this variable can be used to modify the
7776           environment on the target system.  However, how and where it's
7777           used, and even if it's used at all, is entirely dependent on both
7778           the transport mechanism (targetrun) and what the target system is.
7779           Unless the relevant documentation says otherwise, it is genereally
7780           not useful.
7781
7782       "targethost"
7783           From Cross.U:
7784
7785           This variable contains the name of a separate host machine that can
7786           be used to run compiled test programs and perl tests on.  Set to
7787           empty string if not in use.
7788
7789       "targetmkdir"
7790           From Cross.U:
7791
7792           This variable contains the command used by Configure to create a
7793           new directory on the target host.
7794
7795       "targetport"
7796           From Cross.U:
7797
7798           This variable contains the number of a network port to be used to
7799           connect to the host in targethost, if unset defaults to 22 for ssh.
7800
7801       "targetsh"
7802           From sh.U:
7803
7804           If cross-compiling, this variable contains the location of sh on
7805           the target system.  If not, this will be the same as $sh.
7806
7807       "tbl"
7808           From Loc.U:
7809
7810           This variable is defined but not used by Configure.  The value is
7811           the empty string and is not useful.
7812
7813       "tee"
7814           From Loc.U:
7815
7816           This variable is defined but not used by Configure.  The value is
7817           the empty string and is not useful.
7818
7819       "test"
7820           From Loc.U:
7821
7822           This variable is used internally by Configure to determine the full
7823           pathname (if any) of the test program.  After Configure runs, the
7824           value is reset to a plain "test" and is not useful.
7825
7826       "timeincl"
7827           From i_time.U:
7828
7829           This variable holds the full path of the included time header(s).
7830
7831       "timetype"
7832           From d_time.U:
7833
7834           This variable holds the type returned by time(). It can be long, or
7835           time_t on "BSD" sites (in which case <sys/types.h> should be
7836           included). Anyway, the type Time_t should be used.
7837
7838       "tmpnam_r_proto"
7839           From d_tmpnam_r.U:
7840
7841           This variable encodes the prototype of tmpnam_r.  It is zero if
7842           d_tmpnam_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
7843           of reentr.h if d_tmpnam_r is defined.
7844
7845       "to"
7846           From Cross.U:
7847
7848           This variable contains the command used by Configure to copy to
7849           from the target host.  Useful and available only during Perl build.
7850           The string ":" if not cross-compiling.
7851
7852       "touch"
7853           From Loc.U:
7854
7855           This variable is used internally by Configure to determine the full
7856           pathname (if any) of the touch program.  After Configure runs, the
7857           value is reset to a plain "touch" and is not useful.
7858
7859       "tr"
7860           From Loc.U:
7861
7862           This variable is used internally by Configure to determine the full
7863           pathname (if any) of the tr program.  After Configure runs, the
7864           value is reset to a plain "tr" and is not useful.
7865
7866       "trnl"
7867           From trnl.U:
7868
7869           This variable contains the value to be passed to the tr(1) command
7870           to transliterate a newline.  Typical values are "\012" and "\n".
7871           This is needed for "EBCDIC" systems where newline is not
7872           necessarily "\012".
7873
7874       "troff"
7875           From Loc.U:
7876
7877           This variable is defined but not used by Configure.  The value is
7878           the empty string and is not useful.
7879
7880       "ttyname_r_proto"
7881           From d_ttyname_r.U:
7882
7883           This variable encodes the prototype of ttyname_r.  It is zero if
7884           d_ttyname_r is undef, and one of the "REENTRANT_PROTO_T_ABC" macros
7885           of reentr.h if d_ttyname_r is defined.
7886
7887   u
7888       "u16size"
7889           From perlxv.U:
7890
7891           This variable is the size of an U16 in bytes.
7892
7893       "u16type"
7894           From perlxv.U:
7895
7896           This variable contains the C type used for Perl's U16.
7897
7898       "u32size"
7899           From perlxv.U:
7900
7901           This variable is the size of an U32 in bytes.
7902
7903       "u32type"
7904           From perlxv.U:
7905
7906           This variable contains the C type used for Perl's U32.
7907
7908       "u64size"
7909           From perlxv.U:
7910
7911           This variable is the size of an U64 in bytes.
7912
7913       "u64type"
7914           From perlxv.U:
7915
7916           This variable contains the C type used for Perl's U64.
7917
7918       "u8size"
7919           From perlxv.U:
7920
7921           This variable is the size of an U8 in bytes.
7922
7923       "u8type"
7924           From perlxv.U:
7925
7926           This variable contains the C type used for Perl's U8.
7927
7928       "uidformat"
7929           From uidf.U:
7930
7931           This variable contains the format string used for printing a Uid_t.
7932
7933       "uidsign"
7934           From uidsign.U:
7935
7936           This variable contains the signedness of a uidtype.  1 for
7937           unsigned, -1 for signed.
7938
7939       "uidsize"
7940           From uidsize.U:
7941
7942           This variable contains the size of a uidtype in bytes.
7943
7944       "uidtype"
7945           From uidtype.U:
7946
7947           This variable defines Uid_t to be something like uid_t, int,
7948           ushort, or whatever type is used to declare user ids in the kernel.
7949
7950       "uname"
7951           From Loc.U:
7952
7953           This variable is used internally by Configure to determine the full
7954           pathname (if any) of the uname program.  After Configure runs, the
7955           value is reset to a plain "uname" and is not useful.
7956
7957       "uniq"
7958           From Loc.U:
7959
7960           This variable is used internally by Configure to determine the full
7961           pathname (if any) of the uniq program.  After Configure runs, the
7962           value is reset to a plain "uniq" and is not useful.
7963
7964       "uquadtype"
7965           From quadtype.U:
7966
7967           This variable defines Uquad_t to be something like unsigned long,
7968           unsigned int, unsigned long long, uint64_t, or whatever type is
7969           used for 64-bit integers.
7970
7971       "use5005threads"
7972           From usethreads.U:
7973
7974           This variable conditionally defines the USE_5005THREADS symbol, and
7975           indicates that Perl should be built to use the 5.005-based
7976           threading implementation. Only valid up to 5.8.x.
7977
7978       "use64bitall"
7979           From use64bits.U:
7980
7981           This variable conditionally defines the USE_64_BIT_ALL symbol, and
7982           indicates that 64-bit integer types should be used when available.
7983           The maximal possible 64-bitness is employed: LP64 or ILP64, meaning
7984           that you will be able to use more than 2 gigabytes of memory.  This
7985           mode is even more binary incompatible than USE_64_BIT_INT. You may
7986           not be able to run the resulting executable in a 32-bit "CPU" at
7987           all or you may need at least to reboot your "OS" to 64-bit mode.
7988
7989       "use64bitint"
7990           From use64bits.U:
7991
7992           This variable conditionally defines the USE_64_BIT_INT symbol, and
7993           indicates that 64-bit integer types should be used when available.
7994           The minimal possible 64-bitness is employed, just enough to get
7995           64-bit integers into Perl.  This may mean using for example "long
7996           longs", while your memory may still be limited to 2 gigabytes.
7997
7998       "usecbacktrace"
7999           From usebacktrace.U:
8000
8001           This variable indicates whether we are compiling with backtrace
8002           support.
8003
8004       "usecrosscompile"
8005           From Cross.U:
8006
8007           This variable conditionally defines the "USE_CROSS_COMPILE" symbol,
8008           and indicates that Perl has been cross-compiled.
8009
8010       "usedevel"
8011           From Devel.U:
8012
8013           This variable indicates that Perl was configured with development
8014           features enabled.  This should not be done for production builds.
8015
8016       "usedl"
8017           From dlsrc.U:
8018
8019           This variable indicates if the system supports dynamic loading of
8020           some sort.  See also dlsrc and dlobj.
8021
8022       "usedtrace"
8023           From usedtrace.U:
8024
8025           This variable indicates whether we are compiling with dtrace
8026           support. See also dtrace.
8027
8028       "usefaststdio"
8029           From usefaststdio.U:
8030
8031           This variable conditionally defines the "USE_FAST_STDIO" symbol,
8032           and indicates that Perl should be built to use "fast stdio".
8033           Defaults to define in Perls 5.8 and earlier, to undef later.
8034
8035       "useithreads"
8036           From usethreads.U:
8037
8038           This variable conditionally defines the "USE_ITHREADS" symbol, and
8039           indicates that Perl should be built to use the interpreter-based
8040           threading implementation.
8041
8042       "usekernprocpathname"
8043           From usekernprocpathname.U:
8044
8045           This variable, indicates that we can use sysctl with
8046           "KERN_PROC_PATHNAME" to get a full path for the executable, and
8047           hence convert $^X to an absolute path.
8048
8049       "uselargefiles"
8050           From uselfs.U:
8051
8052           This variable conditionally defines the "USE_LARGE_FILES" symbol,
8053           and indicates that large file interfaces should be used when
8054           available.
8055
8056       "uselongdouble"
8057           From uselongdbl.U:
8058
8059           This variable conditionally defines the "USE_LONG_DOUBLE" symbol,
8060           and indicates that long doubles should be used when available.
8061
8062       "usemallocwrap"
8063           From mallocsrc.U:
8064
8065           This variable contains y if we are wrapping malloc to prevent
8066           integer overflow during size calculations.
8067
8068       "usemorebits"
8069           From usemorebits.U:
8070
8071           This variable conditionally defines the "USE_MORE_BITS" symbol, and
8072           indicates that explicit 64-bit interfaces and long doubles should
8073           be used when available.
8074
8075       "usemultiplicity"
8076           From usemultiplicity.U:
8077
8078           This variable conditionally defines the "MULTIPLICITY" symbol, and
8079           indicates that Perl should be built to use multiplicity.
8080
8081       "usemymalloc"
8082           From mallocsrc.U:
8083
8084           This variable contains y if the malloc that comes with this package
8085           is desired over the system's version of malloc.  People often
8086           include special versions of malloc for efficiency, but such
8087           versions are often less portable.  See also mallocsrc and
8088           mallocobj.  If this is "y", then -lmalloc is removed from $libs.
8089
8090       "usenm"
8091           From usenm.U:
8092
8093           This variable contains "true" or "false" depending whether the nm
8094           extraction is wanted or not.
8095
8096       "usensgetexecutablepath"
8097           From usensgetexecutablepath.U:
8098
8099           This symbol, if defined, indicates that we can use
8100           _NSGetExecutablePath and realpath to get a full path for the
8101           executable, and hence convert $^X to an absolute path.
8102
8103       "useopcode"
8104           From Extensions.U:
8105
8106           This variable holds either "true" or "false" to indicate whether
8107           the Opcode extension should be used.  The sole use for this
8108           currently is to allow an easy mechanism for users to skip the
8109           Opcode extension from the Configure command line.
8110
8111       "useperlio"
8112           From useperlio.U:
8113
8114           This variable conditionally defines the "USE_PERLIO" symbol, and
8115           indicates that the PerlIO abstraction should be used throughout.
8116
8117       "useposix"
8118           From Extensions.U:
8119
8120           This variable holds either "true" or "false" to indicate whether
8121           the "POSIX" extension should be used.  The sole use for this
8122           currently is to allow an easy mechanism for hints files to indicate
8123           that "POSIX" will not compile on a particular system.
8124
8125       "usequadmath"
8126           From usequadmath.U:
8127
8128           This variable conditionally defines the "USE_QUADMATH" symbol, and
8129           indicates that the quadmath library __float128 long doubles should
8130           be used when available.
8131
8132       "usereentrant"
8133           From usethreads.U:
8134
8135           This variable conditionally defines the "USE_REENTRANT_API" symbol,
8136           which indicates that the thread code may try to use the various _r
8137           versions of library functions.  This is only potentially meaningful
8138           if usethreads is set and is very experimental, it is not even
8139           prompted for.
8140
8141       "userelocatableinc"
8142           From bin.U:
8143
8144           This variable is set to true to indicate that perl should relocate
8145           @"INC" entries at runtime based on the path to the perl binary.
8146           Any @"INC" paths starting .../ are relocated relative to the
8147           directory containing the perl binary, and a logical cleanup of the
8148           path is then made around the join point (removing dir/../ pairs)
8149
8150       "useshrplib"
8151           From libperl.U:
8152
8153           This variable is set to "true" if the user wishes to build a shared
8154           libperl, and "false" otherwise.
8155
8156       "usesitecustomize"
8157           From d_sitecustomize.U:
8158
8159           This variable is set to true when the user requires a mechanism
8160           that allows the sysadmin to add entries to @"INC" at runtime.  This
8161           variable being set, makes perl run $sitelib/sitecustomize.pl at
8162           startup.
8163
8164       "usesocks"
8165           From usesocks.U:
8166
8167           This variable conditionally defines the "USE_SOCKS" symbol, and
8168           indicates that Perl should be built to use "SOCKS".
8169
8170       "usethreads"
8171           From usethreads.U:
8172
8173           This variable conditionally defines the "USE_THREADS" symbol, and
8174           indicates that Perl should be built to use threads.
8175
8176       "usevendorprefix"
8177           From vendorprefix.U:
8178
8179           This variable tells whether the vendorprefix and consequently other
8180           vendor* paths are in use.
8181
8182       "useversionedarchname"
8183           From archname.U:
8184
8185           This variable indicates whether to include the $api_versionstring
8186           as a component of the $archname.
8187
8188       "usevfork"
8189           From d_vfork.U:
8190
8191           This variable is set to true when the user accepts to use vfork.
8192           It is set to false when no vfork is available or when the user
8193           explicitly requests not to use vfork.
8194
8195       "usrinc"
8196           From usrinc.U:
8197
8198           This variable holds the path of the include files, which is usually
8199           /usr/include. It is mainly used by other Configure units.
8200
8201       "uuname"
8202           From Loc.U:
8203
8204           This variable is defined but not used by Configure.  The value is
8205           the empty string and is not useful.
8206
8207       "uvoformat"
8208           From perlxvf.U:
8209
8210           This variable contains the format string used for printing a Perl
8211           "UV" as an unsigned octal integer.
8212
8213       "uvsize"
8214           From perlxv.U:
8215
8216           This variable is the size of a "UV" in bytes.
8217
8218       "uvtype"
8219           From perlxv.U:
8220
8221           This variable contains the C type used for Perl's "UV".
8222
8223       "uvuformat"
8224           From perlxvf.U:
8225
8226           This variable contains the format string used for printing a Perl
8227           "UV" as an unsigned decimal integer.
8228
8229       "uvxformat"
8230           From perlxvf.U:
8231
8232           This variable contains the format string used for printing a Perl
8233           "UV" as an unsigned hexadecimal integer in lowercase abcdef.
8234
8235       "uvXUformat"
8236           From perlxvf.U:
8237
8238           This variable contains the format string used for printing a Perl
8239           "UV" as an unsigned hexadecimal integer in uppercase "ABCDEF".
8240
8241   v
8242       "vaproto"
8243           From vaproto.U:
8244
8245           This variable conditionally defines "CAN_VAPROTO" on systems
8246           supporting prototype declaration of functions with a variable
8247           number of arguments. See also prototype.
8248
8249       "vendorarch"
8250           From vendorarch.U:
8251
8252           This variable contains the value of the "PERL_VENDORARCH" symbol.
8253           It may have a ~ on the front.  The standard distribution will put
8254           nothing in this directory.  Vendors who distribute perl may wish to
8255           place their own architecture-dependent modules and extensions in
8256           this directory with MakeMaker Makefile.PL "INSTALLDIRS"=vendor or
8257           equivalent.  See "INSTALL" for details.
8258
8259       "vendorarchexp"
8260           From vendorarch.U:
8261
8262           This variable is the ~name expanded version of vendorarch, so that
8263           you may use it directly in Makefiles or shell scripts.
8264
8265       "vendorbin"
8266           From vendorbin.U:
8267
8268           This variable contains the eventual value of the "VENDORBIN"
8269           symbol.  It may have a ~ on the front.  The standard distribution
8270           will put nothing in this directory.  Vendors who distribute perl
8271           may wish to place additional binaries in this directory with
8272           MakeMaker Makefile.PL "INSTALLDIRS"=vendor or equivalent.  See
8273           "INSTALL" for details.
8274
8275       "vendorbinexp"
8276           From vendorbin.U:
8277
8278           This variable is the ~name expanded version of vendorbin, so that
8279           you may use it directly in Makefiles or shell scripts.
8280
8281       "vendorhtml1dir"
8282           From vendorhtml1dir.U:
8283
8284           This variable contains the name of the directory for html pages.
8285           It may have a ~ on the front.  The standard distribution will put
8286           nothing in this directory.  Vendors who distribute perl may wish to
8287           place their own html pages in this directory with MakeMaker
8288           Makefile.PL "INSTALLDIRS"=vendor or equivalent.  See "INSTALL" for
8289           details.
8290
8291       "vendorhtml1direxp"
8292           From vendorhtml1dir.U:
8293
8294           This variable is the ~name expanded version of vendorhtml1dir, so
8295           that you may use it directly in Makefiles or shell scripts.
8296
8297       "vendorhtml3dir"
8298           From vendorhtml3dir.U:
8299
8300           This variable contains the name of the directory for html library
8301           pages.  It may have a ~ on the front.  The standard distribution
8302           will put nothing in this directory.  Vendors who distribute perl
8303           may wish to place their own html pages for modules and extensions
8304           in this directory with MakeMaker Makefile.PL "INSTALLDIRS"=vendor
8305           or equivalent.  See "INSTALL" for details.
8306
8307       "vendorhtml3direxp"
8308           From vendorhtml3dir.U:
8309
8310           This variable is the ~name expanded version of vendorhtml3dir, so
8311           that you may use it directly in Makefiles or shell scripts.
8312
8313       "vendorlib"
8314           From vendorlib.U:
8315
8316           This variable contains the eventual value of the "VENDORLIB"
8317           symbol, which is the name of the private library for this package.
8318           The standard distribution will put nothing in this directory.
8319           Vendors who distribute perl may wish to place their own modules in
8320           this directory with MakeMaker Makefile.PL "INSTALLDIRS"=vendor or
8321           equivalent.  See "INSTALL" for details.
8322
8323       "vendorlib_stem"
8324           From vendorlib.U:
8325
8326           This variable is $vendorlibexp with any trailing version-specific
8327           component removed.  The elements in inc_version_list
8328           (inc_version_list.U) can be tacked onto this variable to generate a
8329           list of directories to search.
8330
8331       "vendorlibexp"
8332           From vendorlib.U:
8333
8334           This variable is the ~name expanded version of vendorlib, so that
8335           you may use it directly in Makefiles or shell scripts.
8336
8337       "vendorman1dir"
8338           From vendorman1dir.U:
8339
8340           This variable contains the name of the directory for man1 pages.
8341           It may have a ~ on the front.  The standard distribution will put
8342           nothing in this directory.  Vendors who distribute perl may wish to
8343           place their own man1 pages in this directory with MakeMaker
8344           Makefile.PL "INSTALLDIRS"=vendor or equivalent.  See "INSTALL" for
8345           details.
8346
8347       "vendorman1direxp"
8348           From vendorman1dir.U:
8349
8350           This variable is the ~name expanded version of vendorman1dir, so
8351           that you may use it directly in Makefiles or shell scripts.
8352
8353       "vendorman3dir"
8354           From vendorman3dir.U:
8355
8356           This variable contains the name of the directory for man3 pages.
8357           It may have a ~ on the front.  The standard distribution will put
8358           nothing in this directory.  Vendors who distribute perl may wish to
8359           place their own man3 pages in this directory with MakeMaker
8360           Makefile.PL "INSTALLDIRS"=vendor or equivalent.  See "INSTALL" for
8361           details.
8362
8363       "vendorman3direxp"
8364           From vendorman3dir.U:
8365
8366           This variable is the ~name expanded version of vendorman3dir, so
8367           that you may use it directly in Makefiles or shell scripts.
8368
8369       "vendorprefix"
8370           From vendorprefix.U:
8371
8372           This variable holds the full absolute path of the directory below
8373           which the vendor will install add-on packages.  See "INSTALL" for
8374           usage and examples.
8375
8376       "vendorprefixexp"
8377           From vendorprefix.U:
8378
8379           This variable holds the full absolute path of the directory below
8380           which the vendor will install add-on packages.  Derived from
8381           vendorprefix.
8382
8383       "vendorscript"
8384           From vendorscript.U:
8385
8386           This variable contains the eventual value of the "VENDORSCRIPT"
8387           symbol.  It may have a ~ on the front.  The standard distribution
8388           will put nothing in this directory.  Vendors who distribute perl
8389           may wish to place additional executable scripts in this directory
8390           with MakeMaker Makefile.PL "INSTALLDIRS"=vendor or equivalent.  See
8391           "INSTALL" for details.
8392
8393       "vendorscriptexp"
8394           From vendorscript.U:
8395
8396           This variable is the ~name expanded version of vendorscript, so
8397           that you may use it directly in Makefiles or shell scripts.
8398
8399       "version"
8400           From patchlevel.U:
8401
8402           The full version number of this package, such as 5.6.1 (or 5_6_1).
8403           This combines revision, patchlevel, and subversion to get the full
8404           version number, including any possible subversions.  This is
8405           suitable for use as a directory name, and hence is filesystem
8406           dependent.
8407
8408       "version_patchlevel_string"
8409           From patchlevel.U:
8410
8411           This is a string combining version, subversion and perl_patchlevel
8412           (if perl_patchlevel is non-zero).  It is typically something like
8413           'version 7 subversion 1'  or 'version 7 subversion 1 patchlevel
8414           11224' It is computed here to avoid duplication of code in
8415           myconfig.SH and lib/Config.pm.
8416
8417       "versiononly"
8418           From versiononly.U:
8419
8420           If set, this symbol indicates that only the version-specific
8421           components of a perl installation should be installed.  This may be
8422           useful for making a test installation of a new version without
8423           disturbing the existing installation.  Setting versiononly is
8424           equivalent to setting installperl's -v option.  In particular, the
8425           non-versioned scripts and programs such as a2p, c2ph, h2xs, pod2*,
8426           and perldoc are not installed (see "INSTALL" for a more complete
8427           list).  Nor are the man pages installed.  Usually, this is undef.
8428
8429       "vi"
8430           From Loc.U:
8431
8432           This variable is defined but not used by Configure.  The value is
8433           the empty string and is not useful.
8434
8435   x
8436       "xlibpth"
8437           From libpth.U:
8438
8439           This variable holds extra path (space-separated) used to find
8440           libraries on this platform, for example "CPU"-specific libraries
8441           (on multi-"CPU" platforms) may be listed here.
8442
8443   y
8444       "yacc"
8445           From yacc.U:
8446
8447           This variable holds the name of the compiler compiler we want to
8448           use in the Makefile. It can be yacc, byacc, or bison -y.
8449
8450       "yaccflags"
8451           From yacc.U:
8452
8453           This variable contains any additional yacc flags desired by the
8454           user.  It is up to the Makefile to use this.
8455
8456   z
8457       "zcat"
8458           From Loc.U:
8459
8460           This variable is defined but not used by Configure.  The value is
8461           the empty string and is not useful.
8462
8463       "zip"
8464           From Loc.U:
8465
8466           This variable is used internally by Configure to determine the full
8467           pathname (if any) of the zip program.  After Configure runs, the
8468           value is reset to a plain "zip" and is not useful.
8469

GIT DATA

8471       Information on the git commit from which the current perl binary was
8472       compiled can be found in the variable $Config::Git_Data.  The variable
8473       is a structured string that looks something like this:
8474
8475         git_commit_id='ea0c2dbd5f5ac6845ecc7ec6696415bf8e27bd52'
8476         git_describe='GitLive-blead-1076-gea0c2db'
8477         git_branch='smartmatch'
8478         git_uncommitted_changes=''
8479         git_commit_id_title='Commit id:'
8480         git_commit_date='2009-05-09 17:47:31 +0200'
8481
8482       Its format is not guaranteed not to change over time.
8483

NOTE

8485       This module contains a good example of how to use tie to implement a
8486       cache and an example of how to make a tied variable readonly to those
8487       outside of it.
8488
8489
8490
8491perl v5.26.3                      2019-05-11                       Config(3pm)
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