Config(3pm) Perl Programmers Reference Guide Config(3pm)

NAME
       Config - access Perl configuration information

SYNOPSIS
           use Config;
           if ($Config{usethreads}) {
               print "has thread support\n"
           }

           use Config qw(myconfig configsh configvars configre);

           print myconfig();

           print configsh();

           print configre();

           configvars(qw(osname archname));

DESCRIPTION
       The Config module contains all the information that was available to
       the "Configure" program at Perl build time (over 900 values).

       Shell variables from the config.sh file (written by Configure) are
       stored in the readonly-variable %Config, indexed by their names.

       Values stored in config.sh as 'undef' are returned as undefined values.
       The perl "exists" function can be used to check if a named variable
       exists.

       For a description of the variables, please have a look at the Glossary
       file, as written in the Porting folder, or use the url:
       http://perl5.git.perl.org/perl.git/blob/HEAD:/Porting/Glossary

       myconfig()
           Returns a textual summary of the major perl configuration values.
           See also "-V" in "Command Switches" in perlrun.

       configsh()
           Returns the entire perl configuration information in the form of
           the original config.sh shell variable assignment script.

       configre($regex)
           Like configsh() but returns, as a list, only the config entries
           who's names match the $regex.

       configvars(@names)
           Prints to STDOUT the values of the named configuration variable.
           Each is printed on a separate line in the form:

             name='value';

           Names which are unknown are output as "name='UNKNOWN';".  See also
           "-V:name" in "Command Switches" in perlrun.

       bincompatoptions()
           Returns a list of C pre-processor options used when compiling this
           perl binary, which affect its binary compatibility with extensions.
           "bincompatoptions()" and "nonbincompatoptions()" are shown
           together in the output of "perl -V" as Compile-time options.

       nonbincompatoptions()
           Returns a list of C pre-processor options used when compiling this
           perl binary, which do not affect binary compatibility with
           extensions.

       compiledate()
           Returns the compile date (as a string), equivalent to what is shown
           by "perl -V"

       localpatches()
           Returns a list of the names of locally applied patches, equivalent
           to what is shown by "perl -V".

       headerfiles()
           Returns a list of the header files that should be used as
           dependencies for XS code, for this version of Perl on this
           platform.

EXAMPLE
       Here's a more sophisticated example of using %Config:

           use Config;
           use strict;

           my %signum;
           my @signame;
           unless($Config{signame} && $Config{signum}) {
               die "No sigs?";
           } else {
               my @names = split ' ', $Config{signame};
               @signum{@names} = split ' ', $Config{signum};
               foreach (@names) {
                   $signame[$signum{$}] ||= $;
               }
           }

           print "signal #17 = $signame[17]\n";
           if ($signum{ALRM}) {
               print "SIGALRM is $signum{ALRM}\n";
           }

WARNING
       Because this information is not stored within the perl executable
       itself it is possible (but unlikely) that the information does not
       relate to the actual perl binary which is being used to access it.

       The Config module is installed into the architecture and version
       specific library directory ($Config{installarchlib}) and it checks the
       perl version number when loaded.

       The values stored in config.sh may be either single-quoted or double-
       quoted. Double-quoted strings are handy for those cases where you need
       to include escape sequences in the strings. To avoid runtime variable
       interpolation, any "$" and "@" characters are replaced by "\$" and
       "\@", respectively. This isn't foolproof, of course, so don't embed
       "\$" or "\@" in double-quoted strings unless you're willing to deal
       with the consequences. (The slashes will end up escaped and the "$" or
       "@" will trigger variable interpolation)

GLOSSARY
       Most "Config" variables are determined by the "Configure" script on
       platforms supported by it (which is most UNIX platforms).  Some
       platforms have custom-made "Config" variables, and may thus not have
       some of the variables described below, or may have extraneous variables
       specific to that particular port.  See the port specific documentation
       in such cases.

   
       "a"
           From Unix.U:

           This variable defines the extension used for ordinary library
           files.  For unix, it is .a.  The . is included.  Other possible
           values include .lib.

       "exe"
           From Unix.U:

           This variable defines the extension used for executable files.
           "DJGPP", Cygwin and OS/2 use .exe.  Stratus "VOS" uses .pm.  On
           operating systems which do not require a specific extension for
           executable files, this variable is empty.

       "o"
           From Unix.U:

           This variable defines the extension used for object files.  For
           unix, it is .o.  The . is included.  Other possible values include
           .obj.

   a
       "afs"
           From afs.U:

           This variable is set to "true" if "AFS" (Andrew File System) is
           used on the system, "false" otherwise.  It is possible to override
           this with a hint value or command line option, but you'd better
           know what you are doing.

       "afsroot"
           From afs.U:

           This variable is by default set to /afs. In the unlikely case this
           is not the correct root, it is possible to override this with a
           hint value or command line option.  This will be used in subsequent
           tests for AFSness in the configure and test process.

       "alignbytes"
           From alignbytes.U:

           This variable holds the number of bytes required to align a
           double or a long double when applicable. Usual values are 2, 4
           and 8.  The default is eight, for safety.

       "ansi2knr"
           From ansi2knr.U:

           This variable is set if the user needs to run ansi2knr.  Currently,
           this is not supported, so we just abort.

       "aphostname"
           From dgethname.U:

           This variable contains the command which can be used to compute the
           host name. The command is fully qualified by its absolute path, to
           make it safe when used by a process with super-user privileges.

       "apirevision"
           From patchlevel.U:

           The three variables, apirevision, apiversion, and apisubversion,
           specify the version of the oldest perl binary compatible with the
           present perl.  In a full version string such as 5.6.1, apirevision
           is the 5.  Prior to 5.5.640, the format was a floating point
           number, like 5.00563.

           perl.c:incpush() and lib/lib.pm will automatically search in
           $sitelib/.. for older directories back to the limit specified by
           these api variables.  This is only useful if you have a perl
           library directory tree structured like the default one.  See
           "INSTALL" for how this works.  The versioned siteperl directory
           was introduced in 5.005, so that is the lowest possible value.  The
           version list appropriate for the current system is determined in
           incversionlist.U.

           "XXX" To do:  Since compatibility can depend on compile time
           options (such as bincompat, longlong, etc.) it should (perhaps) be
           set by Configure, but currently it isn't.  Currently, we read a
           hard-wired value from patchlevel.h.  Perhaps what we ought to do is
           take the hard-wired value from patchlevel.h but then modify it if
           the current Configure options warrant.  patchlevel.h then would use
           an #ifdef guard.

       "apisubversion"
           From patchlevel.U:

           The three variables, apirevision, apiversion, and apisubversion,
           specify the version of the oldest perl binary compatible with the
           present perl.  In a full version string such as 5.6.1,
           apisubversion is the 1.  See apirevision for full details.

       "apiversion"
           From patchlevel.U:

           The three variables, apirevision, apiversion, and apisubversion,
           specify the version of the oldest perl binary compatible with the
           present perl.  In a full version string such as 5.6.1, apiversion
           is the 6.  See apirevision for full details.  As a special case,
           5.5.0 is rendered in the old-style as 5.005.  (In the 5.0050x
           maintenance series, this was the only versioned directory in
           $sitelib.)

       "apiversionstring"
           From patchlevel.U:

           This variable combines apirevision, apiversion, and
           apisubversion in a format such as 5.6.1 (or 561) suitable for
           use as a directory name.  This is filesystem dependent.

       "ar"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the ar program.  After Configure runs, the
           value is reset to a plain "ar" and is not useful.

       "archlib"
           From archlib.U:

           This variable holds the name of the directory in which the user
           wants to put architecture-dependent public library files for
           $package.  It is most often a local directory such as
           /usr/local/lib.  Programs using this variable must be prepared to
           deal with filename expansion.

       "archlibexp"
           From archlib.U:

           This variable is the same as the archlib variable, but is filename
           expanded at configuration time, for convenient use.

       "archname"
           From archname.U:

           This variable is a short name to characterize the current
           architecture.  It is used mainly to construct the default archlib.

       "archname64"
           From use64bits.U:

           This variable is used for the 64-bitness part of $archname.

       "archobjs"
           From Unix.U:

           This variable defines any additional objects that must be linked in
           with the program on this architecture.  On unix, it is usually
           empty.  It is typically used to include emulations of unix calls or
           other facilities.  For perl on OS/2, for example, this would
           include os2/os2.obj.

       "asctimerproto"
           From dasctimer.U:

           This variable encodes the prototype of asctimer.  It is zero if
           dasctimer is undef, and one of the "REENTRANTPROTOTABC" macros
           of reentr.h if dasctimer is defined.

       "awk"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the awk program.  After Configure runs, the
           value is reset to a plain "awk" and is not useful.

   b
       "baserev"
           From baserev.U:

           The base revision level of this package, from the .package file.

       "bash"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "bin"
           From bin.U:

           This variable holds the name of the directory in which the user
           wants to put publicly executable images for the package in
           question.  It is most often a local directory such as
           /usr/local/bin. Programs using this variable must be prepared to
           deal with ~name substitution.

       "binELF"
           From dlsrc.U:

           This variable saves the result from configure if generated binaries
           are in "ELF" format. Only set to defined when the test has actually
           been performed, and the result was positive.

       "binexp"
           From bin.U:

           This is the same as the bin variable, but is filename expanded at
           configuration time, for use in your makefiles.

       "bison"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the bison program.  After Configure runs, the
           value is reset to a plain "bison" and is not useful.

       "byacc"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the byacc program.  After Configure runs, the
           value is reset to a plain "byacc" and is not useful.

       "byteorder"
           From byteorder.U:

           This variable holds the byte order in a "UV". In the following,
           larger digits indicate more significance.  The variable byteorder
           is either 4321 on a big-endian machine, or 1234 on a little-endian,
           or 87654321 on a Cray ... or 3412 with weird order !

   c
       "c" From n.U:

           This variable contains the \c string if that is what causes the
           echo command to suppress newline.  Otherwise it is null.  Correct
           usage is $echo $n "prompt for a question: $c".

       "castflags"
           From dcastneg.U:

           This variable contains a flag that precise difficulties the
           compiler has casting odd floating values to unsigned long: 0 = ok 1
           = couldn't cast < 0 2 = couldn't cast >= 0x80000000 4 = couldn't
           cast in argument expression list

       "cat"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the cat program.  After Configure runs, the
           value is reset to a plain "cat" and is not useful.

       "cc"
           From cc.U:

           This variable holds the name of a command to execute a C compiler
           which can resolve multiple global references that happen to have
           the same name.  Usual values are "cc" and "gcc".  Fervent "ANSI"
           compilers may be called "c89".  "AIX" has xlc.

       "cccdlflags"
           From dlsrc.U:

           This variable contains any special flags that might need to be
           passed with "cc -c" to compile modules to be used to create a
           shared library that will be used for dynamic loading.  For hpux,
           this should be +z.  It is up to the makefile to use it.

       "ccdlflags"
           From dlsrc.U:

           This variable contains any special flags that might need to be
           passed to cc to link with a shared library for dynamic loading.  It
           is up to the makefile to use it.  For sunos 4.1, it should be
           empty.

       "ccflags"
           From ccflags.U:

           This variable contains any additional C compiler flags desired by
           the user.  It is up to the Makefile to use this.

       "ccflagsuselargefiles"
           From uselfs.U:

           This variable contains the compiler flags needed by large file
           builds and added to ccflags by hints files.

       "ccname"
           From Checkcc.U:

           This can set either by hints files or by Configure.  If using gcc,
           this is gcc, and if not, usually equal to cc, unimpressive, no?
           Some platforms, however, make good use of this by storing the
           flavor of the C compiler being used here.  For example if using the
           Sun WorkShop suite, ccname will be "workshop".

       "ccsymbols"
           From Cppsym.U:

           The variable contains the symbols defined by the C compiler alone.
           The symbols defined by cpp or by cc when it calls cpp are not in
           this list, see cppsymbols and cppccsymbols.  The list is a space-
           separated list of symbol=value tokens.

       "ccversion"
           From Checkcc.U:

           This can set either by hints files or by Configure.  If using a
           (non-gcc) vendor cc, this variable may contain a version for the
           compiler.

       "cfby"
           From cfwho.U:

           Login name of the person who ran the Configure script and answered
           the questions. This is used to tag both config.sh and configh.SH.

       "cfemail"
           From cfemail.U:

           Electronic mail address of the person who ran Configure. This can
           be used by units that require the user's e-mail, like MailList.U.

       "cftime"
           From cfwho.U:

           Holds the output of the "date" command when the configuration file
           was produced. This is used to tag both config.sh and configh.SH.

       "charbits"
           From charsize.U:

           This variable contains the value of the "CHARBITS" symbol, which
           indicates to the C program how many bits there are in a character.

       "charsize"
           From charsize.U:

           This variable contains the value of the "CHARSIZE" symbol, which
           indicates to the C program how many bytes there are in a character.

       "chgrp"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "chmod"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the chmod program.  After Configure runs, the
           value is reset to a plain "chmod" and is not useful.

       "chown"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "clocktype"
           From dtimes.U:

           This variable holds the type returned by times(). It can be long,
           or clockt on "BSD" sites (in which case  should be
           included).

       "comm"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the comm program.  After Configure runs, the
           value is reset to a plain "comm" and is not useful.

       "compress"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "configarg0"
           From Options.U:

           This variable contains the string used to invoke the Configure
           command, as reported by the shell in the $0 variable.

       "configargc"
           From Options.U:

           This variable contains the number of command-line arguments passed
           to Configure, as reported by the shell in the $# variable.  The
           individual arguments are stored as variables configarg1,
           configarg2, etc.

       "configargs"
           From Options.U:

           This variable contains a single string giving the command-line
           arguments passed to Configure. Spaces within arguments, quotes, and
           escaped characters are not correctly preserved.  To reconstruct the
           command line, you must assemble the individual command line pieces,
           given in configarg[0-9]*.

       "contains"
           From contains.U:

           This variable holds the command to do a grep with a proper return
           status.  On most sane systems it is simply "grep".  On insane
           systems it is a grep followed by a cat followed by a test.  This
           variable is primarily for the use of other Configure units.

       "cp"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the cp program.  After Configure runs, the
           value is reset to a plain "cp" and is not useful.

       "cpio"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "cpp"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the cpp program.  After Configure runs, the
           value is reset to a plain "cpp" and is not useful.

       "cppstuff"
           From cppstuff.U:

           This variable contains an identification of the concatenation
           mechanism used by the C preprocessor.

       "cppccsymbols"
           From Cppsym.U:

           The variable contains the symbols defined by the C compiler when it
           calls cpp.  The symbols defined by the cc alone or cpp alone are
           not in this list, see ccsymbols and cppsymbols.  The list is a
           space-separated list of symbol=value tokens.

       "cppflags"
           From ccflags.U:

           This variable holds the flags that will be passed to the C pre-
           processor. It is up to the Makefile to use it.

       "cpplast"
           From cppstdin.U:

           This variable has the same functionality as cppminus, only it
           applies to cpprun and not cppstdin.

       "cppminus"
           From cppstdin.U:

           This variable contains the second part of the string which will
           invoke the C preprocessor on the standard input and produce to
           standard output.  This variable will have the value "-" if cppstdin
           needs a minus to specify standard input, otherwise the value is "".

       "cpprun"
           From cppstdin.U:

           This variable contains the command which will invoke a C
           preprocessor on standard input and put the output to stdout. It is
           guaranteed not to be a wrapper and may be a null string if no
           preprocessor can be made directly available. This preprocessor
           might be different from the one used by the C compiler. Don't
           forget to append cpplast after the preprocessor options.

       "cppstdin"
           From cppstdin.U:

           This variable contains the command which will invoke the C
           preprocessor on standard input and put the output to stdout.  It is
           primarily used by other Configure units that ask about preprocessor
           symbols.

       "cppsymbols"
           From Cppsym.U:

           The variable contains the symbols defined by the C preprocessor
           alone.  The symbols defined by cc or by cc when it calls cpp are
           not in this list, see ccsymbols and cppccsymbols.  The list is a
           space-separated list of symbol=value tokens.

       "cryptrproto"
           From dcryptr.U:

           This variable encodes the prototype of cryptr.  It is zero if
           dcryptr is undef, and one of the "REENTRANTPROTOTABC" macros
           of reentr.h if dcryptr is defined.

       "cryptlib"
           From dcrypt.U:

           This variable holds -lcrypt or the path to a libcrypt.a archive if
           the crypt() function is not defined in the standard C library. It
           is up to the Makefile to use this.

       "csh"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the csh program.  After Configure runs, the
           value is reset to a plain "csh" and is not useful.

       "ctermidrproto"
           From dctermidr.U:

           This variable encodes the prototype of ctermidr.  It is zero if
           dctermidr is undef, and one of the "REENTRANTPROTOTABC" macros
           of reentr.h if dctermidr is defined.

       "ctimerproto"
           From dctimer.U:

           This variable encodes the prototype of ctimer.  It is zero if
           dctimer is undef, and one of the "REENTRANTPROTOTABC" macros
           of reentr.h if dctimer is defined.

   d
       "dfwalk"
           From dfwalk.U:

           This variable conditionally defines "HASFWALK" if fwalk() is
           available to apply a function to all the file handles.

       "daccess"
           From daccess.U:

           This variable conditionally defines "HASACCESS" if the access()
           system call is available to check for access permissions using real
           IDs.

       "daccessx"
           From daccessx.U:

           This variable conditionally defines the "HASACCESSX" symbol, which
           indicates to the C program that the accessx() routine is available.

       "daintl"
           From daintl.U:

           This variable conditionally defines the "HASAINTL" symbol, which
           indicates to the C program that the aintl() routine is available.
           If copysignl is also present we can emulate modfl.

       "dalarm"
           From dalarm.U:

           This variable conditionally defines the "HASALARM" symbol, which
           indicates to the C program that the alarm() routine is available.

       "darchlib"
           From archlib.U:

           This variable conditionally defines "ARCHLIB" to hold the pathname
           of architecture-dependent library files for $package.  If $archlib
           is the same as $privlib, then this is set to undef.

       "dasctime64"
           From dtimefuncs64.U:

           This variable conditionally defines the HASASCTIME64 symbol, which
           indicates to the C program that the asctime64 () routine is
           available.

       "dasctimer"
           From dasctimer.U:

           This variable conditionally defines the "HASASCTIMER" symbol,
           which indicates to the C program that the asctimer() routine is
           available.

       "datolf"
           From atolf.U:

           This variable conditionally defines the "HASATOLF" symbol, which
           indicates to the C program that the atolf() routine is available.

       "datoll"
           From atoll.U:

           This variable conditionally defines the "HASATOLL" symbol, which
           indicates to the C program that the atoll() routine is available.

       "dattributedeprecated"
           From dattribut.U:

           This variable conditionally defines "HASATTRIBUTEDEPRECATED",
           which indicates that "GCC" can handle the attribute for marking
           deprecated APIs

       "dattributeformat"
           From dattribut.U:

           This variable conditionally defines "HASATTRIBUTEFORMAT", which
           indicates the C compiler can check for printf-like formats.

       "dattributemalloc"
           From dattribut.U:

           This variable conditionally defines "HASATTRIBUTEMALLOC", which
           indicates the C compiler can understand functions as having malloc-
           like semantics.

       "dattributenonnull"
           From dattribut.U:

           This variable conditionally defines "HASATTRIBUTENONNULL", which
           indicates that the C compiler can know that certain arguments must
           not be "NULL", and will check accordingly at compile time.

       "dattributenoreturn"
           From dattribut.U:

           This variable conditionally defines "HASATTRIBUTENORETURN", which
           indicates that the C compiler can know that certain functions are
           guaranteed never to return.

       "dattributepure"
           From dattribut.U:

           This variable conditionally defines "HASATTRIBUTEPURE", which
           indicates that the C compiler can know that certain functions are
           "pure" functions, meaning that they have no side effects, and only
           rely on function input and/or global data for their results.

       "dattributeunused"
           From dattribut.U:

           This variable conditionally defines "HASATTRIBUTEUNUSED", which
           indicates that the C compiler can know that certain variables and
           arguments may not always be used, and to not throw warnings if they
           don't get used.

       "dattributewarnunusedresult"
           From dattribut.U:

           This variable conditionally defines
           "HASATTRIBUTEWARNUNUSEDRESULT", which indicates that the C
           compiler can know that certain functions have a return values that
           must not be ignored, such as malloc() or open().

       "dbcmp"
           From dbcmp.U:

           This variable conditionally defines the "HASBCMP" symbol if the
           bcmp() routine is available to compare strings.

       "dbcopy"
           From dbcopy.U:

           This variable conditionally defines the "HASBCOPY" symbol if the
           bcopy() routine is available to copy strings.

       "dbsd"
           From Guess.U:

           This symbol conditionally defines the symbol "BSD" when running on
           a "BSD" system.

       "dbsdgetpgrp"
           From dgetpgrp.U:

           This variable conditionally defines "USEBSDGETPGRP" if getpgrp
           needs one arguments whereas "USG" one needs none.

       "dbsdsetpgrp"
           From dsetpgrp.U:

           This variable conditionally defines "USEBSDSETPGRP" if setpgrp
           needs two arguments whereas "USG" one needs none.  See also
           dsetpgid for a "POSIX" interface.

       "dbuiltinchooseexpr"
           From dbuiltin.U:

           This conditionally defines "HASBUILTINCHOOSEEXPR", which
           indicates that the compiler supports builtinchooseexpr(x,y,z).
           This built-in function is analogous to the "x?y:z" operator in C,
           except that the expression returned has its type unaltered by
           promotion rules. Also, the built-in function does not evaluate the
           expression that was not chosen.

       "dbuiltinexpect"
           From dbuiltin.U:

           This conditionally defines "HASBUILTINEXPECT", which indicates
           that the compiler supports builtinexpect(exp,c).  You may use
           builtinexpect to provide the compiler with branch prediction
           information.

       "dbzero"
           From dbzero.U:

           This variable conditionally defines the "HASBZERO" symbol if the
           bzero() routine is available to set memory to 0.

       "dc99variadicmacros"
           From dc99variadic.U:

           This variable conditionally defines the HASC99VARIADICMACROS
           symbol, which indicates to the C program that C99 variadic macros
           are available.

       "dcasti32"
           From dcasti32.U:

           This variable conditionally defines CASTI32, which indicates
           whether the C compiler can cast large floats to 32-bit ints.

       "dcastneg"
           From dcastneg.U:

           This variable conditionally defines "CASTNEG", which indicates
           whether the C compiler can cast negative float to unsigned.

       "dcharvspr"
           From dvprintf.U:

           This variable conditionally defines "CHARVSPRINTF" if this system
           has vsprintf returning type (char*).  The trend seems to be to
           declare it as "int vsprintf()".

       "dchown"
           From dchown.U:

           This variable conditionally defines the "HASCHOWN" symbol, which
           indicates to the C program that the chown() routine is available.

       "dchroot"
           From dchroot.U:

           This variable conditionally defines the "HASCHROOT" symbol, which
           indicates to the C program that the chroot() routine is available.

       "dchsize"
           From dchsize.U:

           This variable conditionally defines the "CHSIZE" symbol, which
           indicates to the C program that the chsize() routine is available
           to truncate files.  You might need a -lx to get this routine.

       "dclass"
           From dclass.U:

           This variable conditionally defines the "HASCLASS" symbol, which
           indicates to the C program that the class() routine is available.

       "dclearenv"
           From dclearenv.U:

           This variable conditionally defines the "HASCLEARENV" symbol,
           which indicates to the C program that the clearenv () routine is
           available.

       "dclosedir"
           From dclosedir.U:

           This variable conditionally defines "HASCLOSEDIR" if closedir() is
           available.

       "dcmsghdrs"
           From dcmsghdrs.U:

           This variable conditionally defines the "HASSTRUCTCMSGHDR"
           symbol, which indicates that the struct cmsghdr is supported.

       "dconst"
           From dconst.U:

           This variable conditionally defines the "HASCONST" symbol, which
           indicates to the C program that this C compiler knows about the
           const type.

       "dcopysignl"
           From dcopysignl.U:

           This variable conditionally defines the "HASCOPYSIGNL" symbol,
           which indicates to the C program that the copysignl() routine is
           available.  If aintl is also present we can emulate modfl.

       "dcplusplus"
           From dcplusplus.U:

           This variable conditionally defines the "USECPLUSPLUS" symbol,
           which indicates that a C++ compiler was used to compiled Perl and
           will be used to compile extensions.

       "dcrypt"
           From dcrypt.U:

           This variable conditionally defines the "CRYPT" symbol, which
           indicates to the C program that the crypt() routine is available to
           encrypt passwords and the like.

       "dcryptr"
           From dcryptr.U:

           This variable conditionally defines the "HASCRYPTR" symbol, which
           indicates to the C program that the cryptr() routine is available.

       "dcsh"
           From dcsh.U:

           This variable conditionally defines the "CSH" symbol, which
           indicates to the C program that the C-shell exists.

       "dctermid"
           From dctermid.U:

           This variable conditionally defines "CTERMID" if ctermid() is
           available to generate filename for terminal.

       "dctermidr"
           From dctermidr.U:

           This variable conditionally defines the "HASCTERMIDR" symbol,
           which indicates to the C program that the ctermidr() routine is
           available.

       "dctime64"
           From dtimefuncs64.U:

           This variable conditionally defines the HASCTIME64 symbol, which
           indicates to the C program that the ctime64 () routine is
           available.

       "dctimer"
           From dctimer.U:

           This variable conditionally defines the "HASCTIMER" symbol, which
           indicates to the C program that the ctimer() routine is available.

       "dcuserid"
           From dcuserid.U:

           This variable conditionally defines the "HASCUSERID" symbol, which
           indicates to the C program that the cuserid() routine is available
           to get character login names.

       "ddbldig"
           From ddbldig.U:

           This variable conditionally defines ddbldig if this system's
           header files provide "DBLDIG", which is the number of significant
           digits in a double precision number.

       "ddbminitproto"
           From ddbminitproto.U:

           This variable conditionally defines the "HASDBMINITPROTO" symbol,
           which indicates to the C program that the system provides a
           prototype for the dbminit() function.  Otherwise, it is up to the
           program to supply one.

       "ddifftime"
           From ddifftime.U:

           This variable conditionally defines the "HASDIFFTIME" symbol,
           which indicates to the C program that the difftime() routine is
           available.

       "ddifftime64"
           From dtimefuncs64.U:

           This variable conditionally defines the HASDIFFTIME64 symbol,
           which indicates to the C program that the difftime64 () routine is
           available.

       "ddirddfd"
           From ddirddfd.U:

           This variable conditionally defines the "HASDIRDDFD" symbol,
           which indicates that the "DIR" directory stream type contains a
           member variable called ddfd.

       "ddirfd"
           From ddirfd.U:

           This variable conditionally defines the "HASDIRFD" constant, which
           indicates to the C program that dirfd() is available to return the
           file descriptor of a directory stream.

       "ddirnamlen"
           From idirent.U:

           This variable conditionally defines "DIRNAMLEN", which indicates to
           the C program that the length of directory entry names is provided
           by a dnamelen field.

       "ddlerror"
           From ddlerror.U:

           This variable conditionally defines the "HASDLERROR" symbol, which
           indicates to the C program that the dlerror() routine is available.

       "ddlopen"
           From ddlopen.U:

           This variable conditionally defines the "HASDLOPEN" symbol, which
           indicates to the C program that the dlopen() routine is available.

       "ddlsymun"
           From ddlsymun.U:

           This variable conditionally defines "DLSYMNEEDSUNDERSCORE", which
           indicates that we need to prepend an underscore to the symbol name
           before calling dlsym().

       "ddosuid"
           From ddosuid.U:

           This variable conditionally defines the symbol "DOSUID", which
           tells the C program that it should insert setuid emulation code on
           hosts which have setuid #! scripts disabled.

       "ddrand48r"
           From ddrand48r.U:

           This variable conditionally defines the HASDRAND48R symbol, which
           indicates to the C program that the drand48r() routine is
           available.

       "ddrand48proto"
           From ddrand48proto.U:

           This variable conditionally defines the HASDRAND48PROTO symbol,
           which indicates to the C program that the system provides a
           prototype for the drand48() function.  Otherwise, it is up to the
           program to supply one.

       "ddup2"
           From ddup2.U:

           This variable conditionally defines HASDUP2 if dup2() is available
           to duplicate file descriptors.

       "deaccess"
           From deaccess.U:

           This variable conditionally defines the "HASEACCESS" symbol, which
           indicates to the C program that the eaccess() routine is available.

       "dendgrent"
           From dendgrent.U:

           This variable conditionally defines the "HASENDGRENT" symbol,
           which indicates to the C program that the endgrent() routine is
           available for sequential access of the group database.

       "dendgrentr"
           From dendgrentr.U:

           This variable conditionally defines the "HASENDGRENTR" symbol,
           which indicates to the C program that the endgrentr() routine is
           available.

       "dendhent"
           From dendhent.U:

           This variable conditionally defines "HASENDHOSTENT" if
           endhostent() is available to close whatever was being used for host
           queries.

       "dendhostentr"
           From dendhostentr.U:

           This variable conditionally defines the "HASENDHOSTENTR" symbol,
           which indicates to the C program that the endhostentr() routine is
           available.

       "dendnent"
           From dendnent.U:

           This variable conditionally defines "HASENDNETENT" if endnetent()
           is available to close whatever was being used for network queries.

       "dendnetentr"
           From dendnetentr.U:

           This variable conditionally defines the "HASENDNETENTR" symbol,
           which indicates to the C program that the endnetentr() routine is
           available.

       "dendpent"
           From dendpent.U:

           This variable conditionally defines "HASENDPROTOENT" if
           endprotoent() is available to close whatever was being used for
           protocol queries.

       "dendprotoentr"
           From dendprotoentr.U:

           This variable conditionally defines the "HASENDPROTOENTR" symbol,
           which indicates to the C program that the endprotoentr() routine
           is available.

       "dendpwent"
           From dendpwent.U:

           This variable conditionally defines the "HASENDPWENT" symbol,
           which indicates to the C program that the endpwent() routine is
           available for sequential access of the passwd database.

       "dendpwentr"
           From dendpwentr.U:

           This variable conditionally defines the "HASENDPWENTR" symbol,
           which indicates to the C program that the endpwentr() routine is
           available.

       "dendsent"
           From dendsent.U:

           This variable conditionally defines "HASENDSERVENT" if
           endservent() is available to close whatever was being used for
           service queries.

       "dendserventr"
           From dendserventr.U:

           This variable conditionally defines the "HASENDSERVENTR" symbol,
           which indicates to the C program that the endserventr() routine is
           available.

       "deofnblk"
           From nblockio.U:

           This variable conditionally defines "EOFNONBLOCK" if "EOF" can be
           seen when reading from a non-blocking I/O source.

       "deunice"
           From Guess.U:

           This variable conditionally defines the symbols "EUNICE" and "VAX",
           which alerts the C program that it must deal with idiosyncrasies of
           "VMS".

       "dfaststdio"
           From dfaststdio.U:

           This variable conditionally defines the "HASFASTSTDIO" symbol,
           which indicates to the C program that the "fast stdio" is available
           to manipulate the stdio buffers directly.

       "dfchdir"
           From dfchdir.U:

           This variable conditionally defines the "HASFCHDIR" symbol, which
           indicates to the C program that the fchdir() routine is available.

       "dfchmod"
           From dfchmod.U:

           This variable conditionally defines the "HASFCHMOD" symbol, which
           indicates to the C program that the fchmod() routine is available
           to change mode of opened files.

       "dfchown"
           From dfchown.U:

           This variable conditionally defines the "HASFCHOWN" symbol, which
           indicates to the C program that the fchown() routine is available
           to change ownership of opened files.

       "dfcntl"
           From dfcntl.U:

           This variable conditionally defines the "HASFCNTL" symbol, and
           indicates whether the fcntl() function exists

       "dfcntlcanlock"
           From dfcntlcanlock.U:

           This variable conditionally defines the "FCNTLCANLOCK" symbol and
           indicates whether file locking with fcntl() works.

       "dfdmacros"
           From dfdset.U:

           This variable contains the eventual value of the "HASFDMACROS"
           symbol, which indicates if your C compiler knows about the macros
           which manipulate an fdset.

       "dfdset"
           From dfdset.U:

           This variable contains the eventual value of the "HASFDSET"
           symbol, which indicates if your C compiler knows about the fdset
           typedef.

       "dfdsbits"
           From dfdset.U:

           This variable contains the eventual value of the "HASFDSBITS"
           symbol, which indicates if your fdset typedef contains the
           fdsbits member.  If you have an fdset typedef, but the dweebs who
           installed it did a half-fast job and neglected to provide the
           macros to manipulate an fdset, "HASFDSBITS" will let us know how
           to fix the gaffe.

       "dfgetpos"
           From dfgetpos.U:

           This variable conditionally defines "HASFGETPOS" if fgetpos() is
           available to get the file position indicator.

       "dfinite"
           From dfinite.U:

           This variable conditionally defines the "HASFINITE" symbol, which
           indicates to the C program that the finite() routine is available.

       "dfinitel"
           From dfinitel.U:

           This variable conditionally defines the "HASFINITEL" symbol, which
           indicates to the C program that the finitel() routine is available.

       "dflexfnam"
           From dflexfnam.U:

           This variable conditionally defines the "FLEXFILENAMES" symbol,
           which indicates that the system supports filenames longer than 14
           characters.

       "dflock"
           From dflock.U:

           This variable conditionally defines "HASFLOCK" if flock() is
           available to do file locking.

       "dflockproto"
           From dflockproto.U:

           This variable conditionally defines the "HASFLOCKPROTO" symbol,
           which indicates to the C program that the system provides a
           prototype for the flock() function.  Otherwise, it is up to the
           program to supply one.

       "dfork"
           From dfork.U:

           This variable conditionally defines the "HASFORK" symbol, which
           indicates to the C program that the fork() routine is available.

       "dfpclass"
           From dfpclass.U:

           This variable conditionally defines the "HASFPCLASS" symbol,
           which indicates to the C program that the fpclass() routine is
           available.

       "dfpathconf"
           From dpathconf.U:

           This variable conditionally defines the "HASFPATHCONF" symbol,
           which indicates to the C program that the pathconf() routine is
           available to determine file-system related limits and options
           associated with a given open file descriptor.

       "dfpclass"
           From dfpclass.U:

           This variable conditionally defines the "HASFPCLASS" symbol, which
           indicates to the C program that the fpclass() routine is available.

       "dfpclassify"
           From dfpclassify.U:

           This variable conditionally defines the "HASFPCLASSIFY" symbol,
           which indicates to the C program that the fpclassify() routine is
           available.

       "dfpclassl"
           From dfpclassl.U:

           This variable conditionally defines the "HASFPCLASSL" symbol,
           which indicates to the C program that the fpclassl() routine is
           available.

       "dfpos64t"
           From dfpos64t.U:

           This symbol will be defined if the C compiler supports fpos64t.

       "dfrexpl"
           From dfrexpl.U:

           This variable conditionally defines the "HASFREXPL" symbol, which
           indicates to the C program that the frexpl() routine is available.

       "dfsdatas"
           From dfsdatas.U:

           This variable conditionally defines the "HASSTRUCTFSDATA"
           symbol, which indicates that the struct fsdata is supported.

       "dfseeko"
           From dfseeko.U:

           This variable conditionally defines the "HASFSEEKO" symbol, which
           indicates to the C program that the fseeko() routine is available.

       "dfsetpos"
           From dfsetpos.U:

           This variable conditionally defines "HASFSETPOS" if fsetpos() is
           available to set the file position indicator.

       "dfstatfs"
           From dfstatfs.U:

           This variable conditionally defines the "HASFSTATFS" symbol, which
           indicates to the C program that the fstatfs() routine is available.

       "dfstatvfs"
           From dstatvfs.U:

           This variable conditionally defines the "HASFSTATVFS" symbol,
           which indicates to the C program that the fstatvfs() routine is
           available.

       "dfsync"
           From dfsync.U:

           This variable conditionally defines the "HASFSYNC" symbol, which
           indicates to the C program that the fsync() routine is available.

       "dftello"
           From dftello.U:

           This variable conditionally defines the "HASFTELLO" symbol, which
           indicates to the C program that the ftello() routine is available.

       "dftime"
           From dftime.U:

           This variable conditionally defines the "HASFTIME" symbol, which
           indicates that the ftime() routine exists.  The ftime() routine is
           basically a sub-second accuracy clock.

       "dfutimes"
           From dfutimes.U:

           This variable conditionally defines the "HASFUTIMES" symbol, which
           indicates to the C program that the futimes() routine is available.

       "dGconvert"
           From dgconvert.U:

           This variable holds what Gconvert is defined as to convert floating
           point numbers into strings.  By default, Configure sets "this"
           macro to use the first of gconvert, gcvt, or sprintf that pass
           sprintf-%g-like behaviour tests.  If perl is using long doubles,
           the macro uses the first of the following functions that pass
           Configure's tests: qgcvt, sprintf (if Configure knows how to make
           sprintf format long doublessee sPRIgldbl), gconvert, gcvt, and
           sprintf (casting to double).  The gconvertpreference and
           gconvertldpreference variables can be used to alter Configure's
           preferences, for doubles and long doubles, respectively.  If
           present, they contain a space-separated list of one or more of the
           above function names in the order they should be tried.

           dGconvert may be set to override Configure with a platform-
           specific function.  If this function expects a double, a different
           value may need to be set by the uselongdouble.cbu call-back unit so
           that long doubles can be formatted without loss of precision.

       "dgdbmndbmhusesprototypes"
           From indbm.U:

           This variable conditionally defines the "NDBMHUSESPROTOTYPES"
           symbol, which indicates that the gdbm-ndbm.h include file uses real
           "ANSI" C prototypes instead of K&R style function declarations. K&R
           style declarations are unsupported in C++, so the include file
           requires special handling when using a C++ compiler and this
           variable is undefined. Consult the different
           d*ndbmhusesprototypes variables to get the same information for
           alternative ndbm.h include files.

       "dgdbmndbmhusesprototypes"
           From indbm.U:

           This variable conditionally defines the "NDBMHUSESPROTOTYPES"
           symbol, which indicates that the gdbm/ndbm.h include file uses real
           "ANSI" C prototypes instead of K&R style function declarations. K&R
           style declarations are unsupported in C++, so the include file
           requires special handling when using a C++ compiler and this
           variable is undefined. Consult the different
           d*ndbmhusesprototypes variables to get the same information for
           alternative ndbm.h include files.

       "dgetaddrinfo"
           From dgetaddrinfo.U:

           This variable conditionally defines the "HASGETADDRINFO" symbol,
           which indicates to the C program that the getaddrinfo() function is
           available.

       "dgetcwd"
           From dgetcwd.U:

           This variable conditionally defines the "HASGETCWD" symbol, which
           indicates to the C program that the getcwd() routine is available
           to get the current working directory.

       "dgetespwnam"
           From dgetespwnam.U:

           This variable conditionally defines "HASGETESPWNAM" if
           getespwnam() is available to retrieve enhanced (shadow) password
           entries by name.

       "dgetfsstat"
           From dgetfsstat.U:

           This variable conditionally defines the "HASGETFSSTAT" symbol,
           which indicates to the C program that the getfsstat() routine is
           available.

       "dgetgrent"
           From dgetgrent.U:

           This variable conditionally defines the "HASGETGRENT" symbol,
           which indicates to the C program that the getgrent() routine is
           available for sequential access of the group database.

       "dgetgrentr"
           From dgetgrentr.U:

           This variable conditionally defines the "HASGETGRENTR" symbol,
           which indicates to the C program that the getgrentr() routine is
           available.

       "dgetgrgidr"
           From dgetgrgidr.U:

           This variable conditionally defines the "HASGETGRGIDR" symbol,
           which indicates to the C program that the getgrgidr() routine is
           available.

       "dgetgrnamr"
           From dgetgrnamr.U:

           This variable conditionally defines the "HASGETGRNAMR" symbol,
           which indicates to the C program that the getgrnamr() routine is
           available.

       "dgetgrps"
           From dgetgrps.U:

           This variable conditionally defines the "HASGETGROUPS" symbol,
           which indicates to the C program that the getgroups() routine is
           available to get the list of process groups.

       "dgethbyaddr"
           From dgethbyad.U:

           This variable conditionally defines the "HASGETHOSTBYADDR" symbol,
           which indicates to the C program that the gethostbyaddr() routine
           is available to look up hosts by their "IP" addresses.

       "dgethbyname"
           From dgethbynm.U:

           This variable conditionally defines the "HASGETHOSTBYNAME" symbol,
           which indicates to the C program that the gethostbyname() routine
           is available to look up host names in some data base or other.

       "dgethent"
           From dgethent.U:

           This variable conditionally defines "HASGETHOSTENT" if
           gethostent() is available to look up host names in some data base
           or another.

       "dgethname"
           From dgethname.U:

           This variable conditionally defines the "HASGETHOSTNAME" symbol,
           which indicates to the C program that the gethostname() routine may
           be used to derive the host name.

       "dgethostbyaddrr"
           From dgethostbyaddrr.U:

           This variable conditionally defines the "HASGETHOSTBYADDRR"
           symbol, which indicates to the C program that the gethostbyaddrr()
           routine is available.

       "dgethostbynamer"
           From dgethostbynamer.U:

           This variable conditionally defines the "HASGETHOSTBYNAMER"
           symbol, which indicates to the C program that the gethostbynamer()
           routine is available.

       "dgethostentr"
           From dgethostentr.U:

           This variable conditionally defines the "HASGETHOSTENTR" symbol,
           which indicates to the C program that the gethostentr() routine is
           available.

       "dgethostprotos"
           From dgethostprotos.U:

           This variable conditionally defines the "HASGETHOSTPROTOS"
           symbol, which indicates to the C program that  supplies
           prototypes for the various gethost*() functions.  See also
           netdbtype.U for probing for various netdb types.

       "dgetitimer"
           From dgetitimer.U:

           This variable conditionally defines the "HASGETITIMER" symbol,
           which indicates to the C program that the getitimer() routine is
           available.

       "dgetlogin"
           From dgetlogin.U:

           This variable conditionally defines the "HASGETLOGIN" symbol,
           which indicates to the C program that the getlogin() routine is
           available to get the login name.

       "dgetloginr"
           From dgetloginr.U:

           This variable conditionally defines the "HASGETLOGINR" symbol,
           which indicates to the C program that the getloginr() routine is
           available.

       "dgetmnt"
           From dgetmnt.U:

           This variable conditionally defines the "HASGETMNT" symbol, which
           indicates to the C program that the getmnt() routine is available
           to retrieve one or more mount info blocks by filename.

       "dgetmntent"
           From dgetmntent.U:

           This variable conditionally defines the "HASGETMNTENT" symbol,
           which indicates to the C program that the getmntent() routine is
           available to iterate through mounted files to get their mount info.

       "dgetnameinfo"
           From dgetnameinfo.U:

           This variable conditionally defines the "HASGETNAMEINFO" symbol,
           which indicates to the C program that the getnameinfo() function is
           available.

       "dgetnbyaddr"
           From dgetnbyad.U:

           This variable conditionally defines the "HASGETNETBYADDR" symbol,
           which indicates to the C program that the getnetbyaddr() routine is
           available to look up networks by their "IP" addresses.

       "dgetnbyname"
           From dgetnbynm.U:

           This variable conditionally defines the "HASGETNETBYNAME" symbol,
           which indicates to the C program that the getnetbyname() routine is
           available to look up networks by their names.

       "dgetnent"
           From dgetnent.U:

           This variable conditionally defines "HASGETNETENT" if getnetent()
           is available to look up network names in some data base or another.

       "dgetnetbyaddrr"
           From dgetnetbyaddrr.U:

           This variable conditionally defines the "HASGETNETBYADDRR"
           symbol, which indicates to the C program that the getnetbyaddrr()
           routine is available.

       "dgetnetbynamer"
           From dgetnetbynamer.U:

           This variable conditionally defines the "HASGETNETBYNAMER"
           symbol, which indicates to the C program that the getnetbynamer()
           routine is available.

       "dgetnetentr"
           From dgetnetentr.U:

           This variable conditionally defines the "HASGETNETENTR" symbol,
           which indicates to the C program that the getnetentr() routine is
           available.

       "dgetnetprotos"
           From dgetnetprotos.U:

           This variable conditionally defines the "HASGETNETPROTOS" symbol,
           which indicates to the C program that  supplies prototypes
           for the various getnet*() functions.  See also netdbtype.U for
           probing for various netdb types.

       "dgetpagsz"
           From dgetpagsz.U:

           This variable conditionally defines "HASGETPAGESIZE" if
           getpagesize() is available to get the system page size.

       "dgetpbyname"
           From dgetprotby.U:

           This variable conditionally defines the "HASGETPROTOBYNAME"
           symbol, which indicates to the C program that the getprotobyname()
           routine is available to look up protocols by their name.

       "dgetpbynumber"
           From dgetprotby.U:

           This variable conditionally defines the "HASGETPROTOBYNUMBER"
           symbol, which indicates to the C program that the
           getprotobynumber() routine is available to look up protocols by
           their number.

       "dgetpent"
           From dgetpent.U:

           This variable conditionally defines "HASGETPROTOENT" if
           getprotoent() is available to look up protocols in some data base
           or another.

       "dgetpgid"
           From dgetpgid.U:

           This variable conditionally defines the "HASGETPGID" symbol, which
           indicates to the C program that the getpgid(pid) function is
           available to get the process group id.

       "dgetpgrp"
           From dgetpgrp.U:

           This variable conditionally defines "HASGETPGRP" if getpgrp() is
           available to get the current process group.

       "dgetpgrp2"
           From dgetpgrp2.U:

           This variable conditionally defines the HASGETPGRP2 symbol, which
           indicates to the C program that the getpgrp2() (as in DG/"UX")
           routine is available to get the current process group.

       "dgetppid"
           From dgetppid.U:

           This variable conditionally defines the "HASGETPPID" symbol, which
           indicates to the C program that the getppid() routine is available
           to get the parent process "ID".

       "dgetprior"
           From dgetprior.U:

           This variable conditionally defines "HASGETPRIORITY" if
           getpriority() is available to get a process's priority.

       "dgetprotobynamer"
           From dgetprotobynamer.U:

           This variable conditionally defines the "HASGETPROTOBYNAMER"
           symbol, which indicates to the C program that the
           getprotobynamer() routine is available.

       "dgetprotobynumberr"
           From dgetprotobynumberr.U:

           This variable conditionally defines the "HASGETPROTOBYNUMBERR"
           symbol, which indicates to the C program that the
           getprotobynumberr() routine is available.

       "dgetprotoentr"
           From dgetprotoentr.U:

           This variable conditionally defines the "HASGETPROTOENTR" symbol,
           which indicates to the C program that the getprotoentr() routine
           is available.

       "dgetprotoprotos"
           From dgetprotoprotos.U:

           This variable conditionally defines the "HASGETPROTOPROTOS"
           symbol, which indicates to the C program that  supplies
           prototypes for the various getproto*() functions.  See also
           netdbtype.U for probing for various netdb types.

       "dgetprpwnam"
           From dgetprpwnam.U:

           This variable conditionally defines "HASGETPRPWNAM" if
           getprpwnam() is available to retrieve protected (shadow) password
           entries by name.

       "dgetpwent"
           From dgetpwent.U:

           This variable conditionally defines the "HASGETPWENT" symbol,
           which indicates to the C program that the getpwent() routine is
           available for sequential access of the passwd database.

       "dgetpwentr"
           From dgetpwentr.U:

           This variable conditionally defines the "HASGETPWENTR" symbol,
           which indicates to the C program that the getpwentr() routine is
           available.

       "dgetpwnamr"
           From dgetpwnamr.U:

           This variable conditionally defines the "HASGETPWNAMR" symbol,
           which indicates to the C program that the getpwnamr() routine is
           available.

       "dgetpwuidr"
           From dgetpwuidr.U:

           This variable conditionally defines the "HASGETPWUIDR" symbol,
           which indicates to the C program that the getpwuidr() routine is
           available.

       "dgetsbyname"
           From dgetsrvby.U:

           This variable conditionally defines the "HASGETSERVBYNAME" symbol,
           which indicates to the C program that the getservbyname() routine
           is available to look up services by their name.

       "dgetsbyport"
           From dgetsrvby.U:

           This variable conditionally defines the "HASGETSERVBYPORT" symbol,
           which indicates to the C program that the getservbyport() routine
           is available to look up services by their port.

       "dgetsent"
           From dgetsent.U:

           This variable conditionally defines "HASGETSERVENT" if
           getservent() is available to look up network services in some data
           base or another.

       "dgetservbynamer"
           From dgetservbynamer.U:

           This variable conditionally defines the "HASGETSERVBYNAMER"
           symbol, which indicates to the C program that the getservbynamer()
           routine is available.

       "dgetservbyportr"
           From dgetservbyportr.U:

           This variable conditionally defines the "HASGETSERVBYPORTR"
           symbol, which indicates to the C program that the getservbyportr()
           routine is available.

       "dgetserventr"
           From dgetserventr.U:

           This variable conditionally defines the "HASGETSERVENTR" symbol,
           which indicates to the C program that the getserventr() routine is
           available.

       "dgetservprotos"
           From dgetservprotos.U:

           This variable conditionally defines the "HASGETSERVPROTOS"
           symbol, which indicates to the C program that  supplies
           prototypes for the various getserv*() functions.  See also
           netdbtype.U for probing for various netdb types.

       "dgetspnam"
           From dgetspnam.U:

           This variable conditionally defines "HASGETSPNAM" if getspnam() is
           available to retrieve SysV shadow password entries by name.

       "dgetspnamr"
           From dgetspnamr.U:

           This variable conditionally defines the "HASGETSPNAMR" symbol,
           which indicates to the C program that the getspnamr() routine is
           available.

       "dgettimeod"
           From dftime.U:

           This variable conditionally defines the "HASGETTIMEOFDAY" symbol,
           which indicates that the gettimeofday() system call exists (to
           obtain a sub-second accuracy clock). You should probably include
           .

       "dgmtime64"
           From dtimefuncs64.U:

           This variable conditionally defines the HASGMTIME64 symbol, which
           indicates to the C program that the gmtime64 () routine is
           available.

       "dgmtimer"
           From dgmtimer.U:

           This variable conditionally defines the "HASGMTIMER" symbol,
           which indicates to the C program that the gmtimer() routine is
           available.

       "dgnulibc"
           From dgnulibc.U:

           Defined if we're dealing with the "GNU" C Library.

       "dgrpasswd"
           From igrp.U:

           This variable conditionally defines "GRPASSWD", which indicates
           that struct group in  contains grpasswd.

       "dhasmntopt"
           From dhasmntopt.U:

           This variable conditionally defines the "HASHASMNTOPT" symbol,
           which indicates to the C program that the hasmntopt() routine is
           available to query the mount options of file systems.

       "dhtonl"
           From dhtonl.U:

           This variable conditionally defines "HASHTONL" if htonl() and its
           friends are available to do network order byte swapping.

       "dilogbl"
           From dilogbl.U:

           This variable conditionally defines the "HASILOGBL" symbol, which
           indicates to the C program that the ilogbl() routine is available.
           If scalbnl is also present we can emulate frexpl.

       "dincversionlist"
           From incversionlist.U:

           This variable conditionally defines "PERLINCVERSIONLIST".  It is
           set to undef when "PERLINCVERSIONLIST" is empty.

       "dindex"
           From dstrchr.U:

           This variable conditionally defines "HASINDEX" if index() and
           rindex() are available for string searching.

       "dinetaton"
           From dinetaton.U:

           This variable conditionally defines the "HASINETATON" symbol,
           which indicates to the C program that the inetaton() function is
           available to parse "IP" address "dotted-quad" strings.

       "dinetntop"
           From dinetntop.U:

           This variable conditionally defines the "HASINETNTOP" symbol,
           which indicates to the C program that the inetntop() function is
           available.

       "dinetpton"
           From dinetpton.U:

           This variable conditionally defines the "HASINETPTON" symbol,
           which indicates to the C program that the inetpton() function is
           available.

       "dint64t"
           From dint64t.U:

           This symbol will be defined if the C compiler supports int64t.

       "dipv6mreq"
           From dsocket.U:

           This variable conditionally defines the HASIPV6MREQ symbol, which
           indicates the availability of a struct ipv6mreq.

       "disascii"
           From disascii.U:

           This variable conditionally defines the "HASISASCII" constant,
           which indicates to the C program that isascii() is available.

       "disblank"
           From disblank.U:

           This variable conditionally defines the "HASISBLANK" constant,
           which indicates to the C program that isblank() is available.

       "disfinite"
           From disfinite.U:

           This variable conditionally defines the "HASISFINITE" symbol,
           which indicates to the C program that the isfinite() routine is
           available.

       "disinf"
           From disinf.U:

           This variable conditionally defines the "HASISINF" symbol, which
           indicates to the C program that the isinf() routine is available.

       "disnan"
           From disnan.U:

           This variable conditionally defines the "HASISNAN" symbol, which
           indicates to the C program that the isnan() routine is available.

       "disnanl"
           From disnanl.U:

           This variable conditionally defines the "HASISNANL" symbol, which
           indicates to the C program that the isnanl() routine is available.

       "dkillpg"
           From dkillpg.U:

           This variable conditionally defines the "HASKILLPG" symbol, which
           indicates to the C program that the killpg() routine is available
           to kill process groups.

       "dlchown"
           From dlchown.U:

           This variable conditionally defines the "HASLCHOWN" symbol, which
           indicates to the C program that the lchown() routine is available
           to operate on a symbolic link (instead of following the link).

       "dldbldig"
           From dldbldig.U:

           This variable conditionally defines dldbldig if this system's
           header files provide "LDBLDIG", which is the number of significant
           digits in a long double precision number.

       "dlibmlibversion"
           From dlibmlibversion.U:

           This variable conditionally defines the "LIBMLIBVERSION" symbol,
           which indicates to the C program that math.h defines "LIBVERSION"
           being available in libm

       "dlink"
           From dlink.U:

           This variable conditionally defines "HASLINK" if link() is
           available to create hard links.

       "dlocaltime64"
           From dtimefuncs64.U:

           This variable conditionally defines the HASLOCALTIME64 symbol,
           which indicates to the C program that the localtime64 () routine is
           available.

       "dlocaltimer"
           From dlocaltimer.U:

           This variable conditionally defines the "HASLOCALTIMER" symbol,
           which indicates to the C program that the localtimer() routine is
           available.

       "dlocaltimerneedstzset"
           From dlocaltimer.U:

           This variable conditionally defines the "LOCALTIMERNEEDSTZSET"
           symbol, which makes us call tzset before localtimer()

       "dlocconv"
           From dlocconv.U:

           This variable conditionally defines "HASLOCALECONV" if
           localeconv() is available for numeric and monetary formatting
           conventions.

       "dlockf"
           From dlockf.U:

           This variable conditionally defines "HASLOCKF" if lockf() is
           available to do file locking.

       "dlongdbl"
           From dlongdbl.U:

           This variable conditionally defines "HASLONGDOUBLE" if the long
           double type is supported.

       "dlonglong"
           From dlonglong.U:

           This variable conditionally defines "HASLONGLONG" if the long
           long type is supported.

       "dlseekproto"
           From dlseekproto.U:

           This variable conditionally defines the "HASLSEEKPROTO" symbol,
           which indicates to the C program that the system provides a
           prototype for the lseek() function.  Otherwise, it is up to the
           program to supply one.

       "dlstat"
           From dlstat.U:

           This variable conditionally defines "HASLSTAT" if lstat() is
           available to do file stats on symbolic links.

       "dmadvise"
           From dmadvise.U:

           This variable conditionally defines "HASMADVISE" if madvise() is
           available to map a file into memory.

       "dmallocgoodsize"
           From dmallocsize.U:

           This symbol, if defined, indicates that the mallocgoodsize
           routine is available for use.

       "dmallocsize"
           From dmallocsize.U:

           This symbol, if defined, indicates that the mallocsize routine is
           available for use.

       "dmblen"
           From dmblen.U:

           This variable conditionally defines the "HASMBLEN" symbol, which
           indicates to the C program that the mblen() routine is available to
           find the number of bytes in a multibye character.

       "dmbstowcs"
           From dmbstowcs.U:

           This variable conditionally defines the "HASMBSTOWCS" symbol,
           which indicates to the C program that the mbstowcs() routine is
           available to convert a multibyte string into a wide character
           string.

       "dmbtowc"
           From dmbtowc.U:

           This variable conditionally defines the "HASMBTOWC" symbol, which
           indicates to the C program that the mbtowc() routine is available
           to convert multibyte to a wide character.

       "dmemchr"
           From dmemchr.U:

           This variable conditionally defines the "HASMEMCHR" symbol, which
           indicates to the C program that the memchr() routine is available
           to locate characters within a C string.

       "dmemcmp"
           From dmemcmp.U:

           This variable conditionally defines the "HASMEMCMP" symbol, which
           indicates to the C program that the memcmp() routine is available
           to compare blocks of memory.

       "dmemcpy"
           From dmemcpy.U:

           This variable conditionally defines the "HASMEMCPY" symbol, which
           indicates to the C program that the memcpy() routine is available
           to copy blocks of memory.

       "dmemmove"
           From dmemmove.U:

           This variable conditionally defines the "HASMEMMOVE" symbol, which
           indicates to the C program that the memmove() routine is available
           to copy potentially overlapping blocks of memory.

       "dmemset"
           From dmemset.U:

           This variable conditionally defines the "HASMEMSET" symbol, which
           indicates to the C program that the memset() routine is available
           to set blocks of memory.

       "dmkdir"
           From dmkdir.U:

           This variable conditionally defines the "HASMKDIR" symbol, which
           indicates to the C program that the mkdir() routine is available to
           create directories..

       "dmkdtemp"
           From dmkdtemp.U:

           This variable conditionally defines the "HASMKDTEMP" symbol, which
           indicates to the C program that the mkdtemp() routine is available
           to exclusively create a uniquely named temporary directory.

       "dmkfifo"
           From dmkfifo.U:

           This variable conditionally defines the "HASMKFIFO" symbol, which
           indicates to the C program that the mkfifo() routine is available.

       "dmkstemp"
           From dmkstemp.U:

           This variable conditionally defines the "HASMKSTEMP" symbol, which
           indicates to the C program that the mkstemp() routine is available
           to exclusively create and open a uniquely named temporary file.

       "dmkstemps"
           From dmkstemps.U:

           This variable conditionally defines the "HASMKSTEMPS" symbol,
           which indicates to the C program that the mkstemps() routine is
           available to exclusively create and open a uniquely named (with a
           suffix) temporary file.

       "dmktime"
           From dmktime.U:

           This variable conditionally defines the "HASMKTIME" symbol, which
           indicates to the C program that the mktime() routine is available.

       "dmktime64"
           From dtimefuncs64.U:

           This variable conditionally defines the HASMKTIME64 symbol, which
           indicates to the C program that the mktime64 () routine is
           available.

       "dmmap"
           From dmmap.U:

           This variable conditionally defines "HASMMAP" if mmap() is
           available to map a file into memory.

       "dmodfl"
           From dmodfl.U:

           This variable conditionally defines the "HASMODFL" symbol, which
           indicates to the C program that the modfl() routine is available.

       "dmodflpow32bug"
           From dmodfl.U:

           This variable conditionally defines the HASMODFLPOW32BUG symbol,
           which indicates that modfl() is broken for long doubles >= pow(2,
           32).  For example from 4294967303.150000 one would get
           4294967302.000000 and 1.150000.  The bug has been seen in certain
           versions of glibc, release 2.2.2 is known to be okay.

       "dmodflproto"
           From dmodfl.U:

           This symbol, if defined, indicates that the system provides a
           prototype for the modfl() function.  Otherwise, it is up to the
           program to supply one.  C99 says it should be long double
           modfl(long double, long double *);

       "dmprotect"
           From dmprotect.U:

           This variable conditionally defines "HASMPROTECT" if mprotect() is
           available to modify the access protection of a memory mapped file.

       "dmsg"
           From dmsg.U:

           This variable conditionally defines the "HASMSG" symbol, which
           indicates that the entire msg*(2) library is present.

       "dmsgctrunc"
           From dsocket.U:

           This variable conditionally defines the "HASMSGCTRUNC" symbol,
           which indicates that the "MSGCTRUNC" is available.  #ifdef is not
           enough because it may be an enum, glibc has been known to do this.

       "dmsgdontroute"
           From dsocket.U:

           This variable conditionally defines the "HASMSGDONTROUTE" symbol,
           which indicates that the "MSGDONTROUTE" is available.  #ifdef is
           not enough because it may be an enum, glibc has been known to do
           this.

       "dmsgoob"
           From dsocket.U:

           This variable conditionally defines the "HASMSGOOB" symbol, which
           indicates that the "MSGOOB" is available.  #ifdef is not enough
           because it may be an enum, glibc has been known to do this.

       "dmsgpeek"
           From dsocket.U:

           This variable conditionally defines the "HASMSGPEEK" symbol,
           which indicates that the "MSGPEEK" is available.  #ifdef is not
           enough because it may be an enum, glibc has been known to do this.

       "dmsgproxy"
           From dsocket.U:

           This variable conditionally defines the "HASMSGPROXY" symbol,
           which indicates that the "MSGPROXY" is available.  #ifdef is not
           enough because it may be an enum, glibc has been known to do this.

       "dmsgctl"
           From dmsgctl.U:

           This variable conditionally defines the "HASMSGCTL" symbol, which
           indicates to the C program that the msgctl() routine is available.

       "dmsgget"
           From dmsgget.U:

           This variable conditionally defines the "HASMSGGET" symbol, which
           indicates to the C program that the msgget() routine is available.

       "dmsghdrs"
           From dmsghdrs.U:

           This variable conditionally defines the "HASSTRUCTMSGHDR" symbol,
           which indicates that the struct msghdr is supported.

       "dmsgrcv"
           From dmsgrcv.U:

           This variable conditionally defines the "HASMSGRCV" symbol, which
           indicates to the C program that the msgrcv() routine is available.

       "dmsgsnd"
           From dmsgsnd.U:

           This variable conditionally defines the "HASMSGSND" symbol, which
           indicates to the C program that the msgsnd() routine is available.

       "dmsync"
           From dmsync.U:

           This variable conditionally defines "HASMSYNC" if msync() is
           available to synchronize a mapped file.

       "dmunmap"
           From dmunmap.U:

           This variable conditionally defines "HASMUNMAP" if munmap() is
           available to unmap a region mapped by mmap().

       "dmymalloc"
           From mallocsrc.U:

           This variable conditionally defines "MYMALLOC" in case other parts
           of the source want to take special action if "MYMALLOC" is used.
           This may include different sorts of profiling or error detection.

       "dndbm"
           From indbm.U:

           This variable conditionally defines the "HASNDBM" symbol, which
           indicates that both the ndbm.h include file and an appropriate ndbm
           library exist.  Consult the different i*ndbm variables to find out
           the actual include location.  Sometimes, a system has the header
           file but not the library.  This variable will only be set if the
           system has both.

       "dndbmhusesprototypes"
           From indbm.U:

           This variable conditionally defines the "NDBMHUSESPROTOTYPES"
           symbol, which indicates that the ndbm.h include file uses real
           "ANSI" C prototypes instead of K&R style function declarations. K&R
           style declarations are unsupported in C++, so the include file
           requires special handling when using a C++ compiler and this
           variable is undefined. Consult the different
           d*ndbmhusesprototypes variables to get the same information for
           alternative ndbm.h include files.

       "dnice"
           From dnice.U:

           This variable conditionally defines the "HASNICE" symbol, which
           indicates to the C program that the nice() routine is available.

       "dnllanginfo"
           From dnllanginfo.U:

           This variable conditionally defines the "HASNLLANGINFO" symbol,
           which indicates to the C program that the nllanginfo() routine is
           available.

       "dnvpreservesuv"
           From perlxv.U:

           This variable indicates whether a variable of type nvtype can
           preserve all the bits a variable of type uvtype.

       "dnvzeroisallbitszero"
           From perlxv.U:

           This variable indicates whether a variable of type nvtype stores
           0.0 in memory as all bits zero.

       "doff64t"
           From doff64t.U:

           This symbol will be defined if the C compiler supports off64t.

       "doldpthreadcreatejoinable"
           From dpthrattrj.U:

           This variable conditionally defines pthreadcreatejoinable.  undef
           if pthread.h defines "PTHREADCREATEJOINABLE".

       "doldpthreads"
           From usethreads.U:

           This variable conditionally defines the "OLDPTHREADSAPI" symbol,
           and indicates that Perl should be built to use the old draft
           "POSIX" threads "API".  This is only potentially meaningful if
           usethreads is set.

       "doldsock"
           From dsocket.U:

           This variable conditionally defines the "OLDSOCKET" symbol, which
           indicates that the "BSD" socket interface is based on 4.1c and not
           4.2.

       "dopen3"
           From dopen3.U:

           This variable conditionally defines the HASOPEN3 manifest
           constant, which indicates to the C program that the 3 argument
           version of the open(2) function is available.

       "dpathconf"
           From dpathconf.U:

           This variable conditionally defines the "HASPATHCONF" symbol,
           which indicates to the C program that the pathconf() routine is
           available to determine file-system related limits and options
           associated with a given filename.

       "dpause"
           From dpause.U:

           This variable conditionally defines the "HASPAUSE" symbol, which
           indicates to the C program that the pause() routine is available to
           suspend a process until a signal is received.

       "dperlotherlibdirs"
           From otherlibdirs.U:

           This variable conditionally defines "PERLOTHERLIBDIRS", which
           contains a colon-separated set of paths for the perl binary to
           include in @"INC".  See also otherlibdirs.

       "dphostname"
           From dgethname.U:

           This variable conditionally defines the "HASPHOSTNAME" symbol,
           which contains the shell command which, when fed to popen(), may be
           used to derive the host name.

       "dpipe"
           From dpipe.U:

           This variable conditionally defines the "HASPIPE" symbol, which
           indicates to the C program that the pipe() routine is available to
           create an inter-process channel.

       "dpoll"
           From dpoll.U:

           This variable conditionally defines the "HASPOLL" symbol, which
           indicates to the C program that the poll() routine is available to
           poll active file descriptors.

       "dportable"
           From dportable.U:

           This variable conditionally defines the "PORTABLE" symbol, which
           indicates to the C program that it should not assume that it is
           running on the machine it was compiled on.

       "dprctl"
           From dprctl.U:

           This variable conditionally defines the "HASPRCTL" symbol, which
           indicates to the C program that the prctl() routine is available.

       "dprctlsetname"
           From dprctl.U:

           This variable conditionally defines the "HASPRCTLSETNAME"
           symbol, which indicates to the C program that the prctl() routine
           supports the "PRSETNAME" option.

       "dPRId64"
           From quadfio.U:

           This variable conditionally defines the PERLPRId64 symbol, which
           indicates that stdio has a symbol to print 64-bit decimal numbers.

       "dPRIeldbl"
           From longdblfio.U:

           This variable conditionally defines the PERLPRIfldbl symbol, which
           indicates that stdio has a symbol to print long doubles.

       "dPRIEUldbl"
           From longdblfio.U:

           This variable conditionally defines the PERLPRIfldbl symbol, which
           indicates that stdio has a symbol to print long doubles.  The "U"
           in the name is to separate this from dPRIeldbl so that even case-
           blind systems can see the difference.

       "dPRIfldbl"
           From longdblfio.U:

           This variable conditionally defines the PERLPRIfldbl symbol, which
           indicates that stdio has a symbol to print long doubles.

       "dPRIFUldbl"
           From longdblfio.U:

           This variable conditionally defines the PERLPRIfldbl symbol, which
           indicates that stdio has a symbol to print long doubles.  The "U"
           in the name is to separate this from dPRIfldbl so that even case-
           blind systems can see the difference.

       "dPRIgldbl"
           From longdblfio.U:

           This variable conditionally defines the PERLPRIfldbl symbol, which
           indicates that stdio has a symbol to print long doubles.

       "dPRIGUldbl"
           From longdblfio.U:

           This variable conditionally defines the PERLPRIfldbl symbol, which
           indicates that stdio has a symbol to print long doubles.  The "U"
           in the name is to separate this from dPRIgldbl so that even case-
           blind systems can see the difference.

       "dPRIi64"
           From quadfio.U:

           This variable conditionally defines the PERLPRIi64 symbol, which
           indicates that stdio has a symbol to print 64-bit decimal numbers.

       "dprintfformatnull"
           From dattribut.U:

           This variable conditionally defines "PRINTFFORMATNULLOK", which
           indicates the C compiler allows printf-like formats to be null.

       "dPRIo64"
           From quadfio.U:

           This variable conditionally defines the PERLPRIo64 symbol, which
           indicates that stdio has a symbol to print 64-bit octal numbers.

       "dPRIu64"
           From quadfio.U:

           This variable conditionally defines the PERLPRIu64 symbol, which
           indicates that stdio has a symbol to print 64-bit unsigned decimal
           numbers.

       "dPRIx64"
           From quadfio.U:

           This variable conditionally defines the PERLPRIx64 symbol, which
           indicates that stdio has a symbol to print 64-bit hexadecimal
           numbers.

       "dPRIXU64"
           From quadfio.U:

           This variable conditionally defines the PERLPRIXU64 symbol, which
           indicates that stdio has a symbol to print 64-bit hExADECimAl
           numbers.  The "U" in the name is to separate this from dPRIx64 so
           that even case-blind systems can see the difference.

       "dprocselfexe"
           From dprocselfexe.U:

           Defined if $procselfexe is symlink to the absolute pathname of the
           executing program.

       "dpseudofork"
           From dvfork.U:

           This variable conditionally defines the "HASPSEUDOFORK" symbol,
           which indicates that an emulation of the fork routine is available.

       "dpthreadatfork"
           From dpthreadatfork.U:

           This variable conditionally defines the "HASPTHREADATFORK"
           symbol, which indicates to the C program that the pthreadatfork()
           routine is available.

       "dpthreadattrsetscope"
           From dpthreadattrss.U:

           This variable conditionally defines "HASPTHREADATTRSETSCOPE" if
           pthreadattrsetscope() is available to set the contention scope
           attribute of a thread attribute object.

       "dpthreadyield"
           From dpthready.U:

           This variable conditionally defines the "HASPTHREADYIELD" symbol
           if the pthreadyield routine is available to yield the execution of
           the current thread.

       "dpwage"
           From ipwd.U:

           This variable conditionally defines "PWAGE", which indicates that
           struct passwd contains pwage.

       "dpwchange"
           From ipwd.U:

           This variable conditionally defines "PWCHANGE", which indicates
           that struct passwd contains pwchange.

       "dpwclass"
           From ipwd.U:

           This variable conditionally defines "PWCLASS", which indicates that
           struct passwd contains pwclass.

       "dpwcomment"
           From ipwd.U:

           This variable conditionally defines "PWCOMMENT", which indicates
           that struct passwd contains pwcomment.

       "dpwexpire"
           From ipwd.U:

           This variable conditionally defines "PWEXPIRE", which indicates
           that struct passwd contains pwexpire.

       "dpwgecos"
           From ipwd.U:

           This variable conditionally defines "PWGECOS", which indicates that
           struct passwd contains pwgecos.

       "dpwpasswd"
           From ipwd.U:

           This variable conditionally defines "PWPASSWD", which indicates
           that struct passwd contains pwpasswd.

       "dpwquota"
           From ipwd.U:

           This variable conditionally defines "PWQUOTA", which indicates that
           struct passwd contains pwquota.

       "dqgcvt"
           From dqgcvt.U:

           This variable conditionally defines the "HASQGCVT" symbol, which
           indicates to the C program that the qgcvt() routine is available.

       "dquad"
           From quadtype.U:

           This variable, if defined, tells that there's a 64-bit integer
           type, quadtype.

       "drandomr"
           From drandomr.U:

           This variable conditionally defines the "HASRANDOMR" symbol,
           which indicates to the C program that the randomr() routine is
           available.

       "dreaddir"
           From dreaddir.U:

           This variable conditionally defines "HASREADDIR" if readdir() is
           available to read directory entries.

       "dreaddir64r"
           From dreaddir64r.U:

           This variable conditionally defines the HASREADDIR64R symbol,
           which indicates to the C program that the readdir64r() routine is
           available.

       "dreaddirr"
           From dreaddirr.U:

           This variable conditionally defines the "HASREADDIRR" symbol,
           which indicates to the C program that the readdirr() routine is
           available.

       "dreadlink"
           From dreadlink.U:

           This variable conditionally defines the "HASREADLINK" symbol,
           which indicates to the C program that the readlink() routine is
           available to read the value of a symbolic link.

       "dreadv"
           From dreadv.U:

           This variable conditionally defines the "HASREADV" symbol, which
           indicates to the C program that the readv() routine is available.

       "drecvmsg"
           From drecvmsg.U:

           This variable conditionally defines the "HASRECVMSG" symbol, which
           indicates to the C program that the recvmsg() routine is available.

       "drename"
           From drename.U:

           This variable conditionally defines the "HASRENAME" symbol, which
           indicates to the C program that the rename() routine is available
           to rename files.

       "drewinddir"
           From dreaddir.U:

           This variable conditionally defines "HASREWINDDIR" if rewinddir()
           is available.

       "drmdir"
           From drmdir.U:

           This variable conditionally defines "HASRMDIR" if rmdir() is
           available to remove directories.

       "dsafebcpy"
           From dsafebcpy.U:

           This variable conditionally defines the "HASSAFEBCOPY" symbol if
           the bcopy() routine can do overlapping copies.  Normally, you
           should probably use memmove().

       "dsafemcpy"
           From dsafemcpy.U:

           This variable conditionally defines the "HASSAFEMEMCPY" symbol if
           the memcpy() routine can do overlapping copies.  For overlapping
           copies, memmove() should be used, if available.

       "dsanemcmp"
           From dsanemcmp.U:

           This variable conditionally defines the "HASSANEMEMCMP" symbol if
           the memcpy() routine is available and can be used to compare
           relative magnitudes of chars with their high bits set.

       "dsbrkproto"
           From dsbrkproto.U:

           This variable conditionally defines the "HASSBRKPROTO" symbol,
           which indicates to the C program that the system provides a
           prototype for the sbrk() function.  Otherwise, it is up to the
           program to supply one.

       "dscalbnl"
           From dscalbnl.U:

           This variable conditionally defines the "HASSCALBNL" symbol, which
           indicates to the C program that the scalbnl() routine is available.
           If ilogbl is also present we can emulate frexpl.

       "dschedyield"
           From dpthready.U:

           This variable conditionally defines the "HASSCHEDYIELD" symbol if
           the schedyield routine is available to yield the execution of the
           current thread.

       "dscmrights"
           From dsocket.U:

           This variable conditionally defines the "HASSCMRIGHTS" symbol,
           which indicates that the "SCMRIGHTS" is available.  #ifdef is not
           enough because it may be an enum, glibc has been known to do this.

       "dSCNfldbl"
           From longdblfio.U:

           This variable conditionally defines the PERLPRIfldbl symbol, which
           indicates that stdio has a symbol to scan long doubles.

       "dseekdir"
           From dreaddir.U:

           This variable conditionally defines "HASSEEKDIR" if seekdir() is
           available.

       "dselect"
           From dselect.U:

           This variable conditionally defines "HASSELECT" if select() is
           available to select active file descriptors. A 
           inclusion may be necessary for the timeout field.

       "dsem"
           From dsem.U:

           This variable conditionally defines the "HASSEM" symbol, which
           indicates that the entire sem*(2) library is present.

       "dsemctl"
           From dsemctl.U:

           This variable conditionally defines the "HASSEMCTL" symbol, which
           indicates to the C program that the semctl() routine is available.

       "dsemctlsemidds"
           From dunionsemun.U:

           This variable conditionally defines "USESEMCTLSEMIDDS", which
           indicates that struct semidds * is to be used for semctl
           "IPCSTAT".

       "dsemctlsemun"
           From dunionsemun.U:

           This variable conditionally defines "USESEMCTLSEMUN", which
           indicates that union semun is to be used for semctl "IPCSTAT".

       "dsemget"
           From dsemget.U:

           This variable conditionally defines the "HASSEMGET" symbol, which
           indicates to the C program that the semget() routine is available.

       "dsemop"
           From dsemop.U:

           This variable conditionally defines the "HASSEMOP" symbol, which
           indicates to the C program that the semop() routine is available.

       "dsendmsg"
           From dsendmsg.U:

           This variable conditionally defines the "HASSENDMSG" symbol, which
           indicates to the C program that the sendmsg() routine is available.

       "dsetegid"
           From dsetegid.U:

           This variable conditionally defines the "HASSETEGID" symbol, which
           indicates to the C program that the setegid() routine is available
           to change the effective gid of the current program.

       "dseteuid"
           From dseteuid.U:

           This variable conditionally defines the "HASSETEUID" symbol, which
           indicates to the C program that the seteuid() routine is available
           to change the effective uid of the current program.

       "dsetgrent"
           From dsetgrent.U:

           This variable conditionally defines the "HASSETGRENT" symbol,
           which indicates to the C program that the setgrent() routine is
           available for initializing sequential access to the group database.

       "dsetgrentr"
           From dsetgrentr.U:

           This variable conditionally defines the "HASSETGRENTR" symbol,
           which indicates to the C program that the setgrentr() routine is
           available.

       "dsetgrps"
           From dsetgrps.U:

           This variable conditionally defines the "HASSETGROUPS" symbol,
           which indicates to the C program that the setgroups() routine is
           available to set the list of process groups.

       "dsethent"
           From dsethent.U:

           This variable conditionally defines "HASSETHOSTENT" if
           sethostent() is available.

       "dsethostentr"
           From dsethostentr.U:

           This variable conditionally defines the "HASSETHOSTENTR" symbol,
           which indicates to the C program that the sethostentr() routine is
           available.

       "dsetitimer"
           From dsetitimer.U:

           This variable conditionally defines the "HASSETITIMER" symbol,
           which indicates to the C program that the setitimer() routine is
           available.

       "dsetlinebuf"
           From dsetlnbuf.U:

           This variable conditionally defines the "HASSETLINEBUF" symbol,
           which indicates to the C program that the setlinebuf() routine is
           available to change stderr or stdout from block-buffered or
           unbuffered to a line-buffered mode.

       "dsetlocale"
           From dsetlocale.U:

           This variable conditionally defines "HASSETLOCALE" if setlocale()
           is available to handle locale-specific ctype implementations.

       "dsetlocaler"
           From dsetlocaler.U:

           This variable conditionally defines the "HASSETLOCALER" symbol,
           which indicates to the C program that the setlocaler() routine is
           available.

       "dsetnent"
           From dsetnent.U:

           This variable conditionally defines "HASSETNETENT" if setnetent()
           is available.

       "dsetnetentr"
           From dsetnetentr.U:

           This variable conditionally defines the "HASSETNETENTR" symbol,
           which indicates to the C program that the setnetentr() routine is
           available.

       "dsetpent"
           From dsetpent.U:

           This variable conditionally defines "HASSETPROTOENT" if
           setprotoent() is available.

       "dsetpgid"
           From dsetpgid.U:

           This variable conditionally defines the "HASSETPGID" symbol if the
           setpgid(pid, gpid) function is available to set process group "ID".

       "dsetpgrp"
           From dsetpgrp.U:

           This variable conditionally defines "HASSETPGRP" if setpgrp() is
           available to set the current process group.

       "dsetpgrp2"
           From dsetpgrp2.U:

           This variable conditionally defines the HASSETPGRP2 symbol, which
           indicates to the C program that the setpgrp2() (as in DG/"UX")
           routine is available to set the current process group.

       "dsetprior"
           From dsetprior.U:

           This variable conditionally defines "HASSETPRIORITY" if
           setpriority() is available to set a process's priority.

       "dsetproctitle"
           From dsetproctitle.U:

           This variable conditionally defines the "HASSETPROCTITLE" symbol,
           which indicates to the C program that the setproctitle() routine is
           available.

       "dsetprotoentr"
           From dsetprotoentr.U:

           This variable conditionally defines the "HASSETPROTOENTR" symbol,
           which indicates to the C program that the setprotoentr() routine
           is available.

       "dsetpwent"
           From dsetpwent.U:

           This variable conditionally defines the "HASSETPWENT" symbol,
           which indicates to the C program that the setpwent() routine is
           available for initializing sequential access to the passwd
           database.

       "dsetpwentr"
           From dsetpwentr.U:

           This variable conditionally defines the "HASSETPWENTR" symbol,
           which indicates to the C program that the setpwentr() routine is
           available.

       "dsetregid"
           From dsetregid.U:

           This variable conditionally defines "HASSETREGID" if setregid() is
           available to change the real and effective gid of the current
           process.

       "dsetresgid"
           From dsetregid.U:

           This variable conditionally defines "HASSETRESGID" if setresgid()
           is available to change the real, effective and saved gid of the
           current process.

       "dsetresuid"
           From dsetreuid.U:

           This variable conditionally defines "HASSETREUID" if setresuid()
           is available to change the real, effective and saved uid of the
           current process.

       "dsetreuid"
           From dsetreuid.U:

           This variable conditionally defines "HASSETREUID" if setreuid() is
           available to change the real and effective uid of the current
           process.

       "dsetrgid"
           From dsetrgid.U:

           This variable conditionally defines the "HASSETRGID" symbol, which
           indicates to the C program that the setrgid() routine is available
           to change the real gid of the current program.

       "dsetruid"
           From dsetruid.U:

           This variable conditionally defines the "HASSETRUID" symbol, which
           indicates to the C program that the setruid() routine is available
           to change the real uid of the current program.

       "dsetsent"
           From dsetsent.U:

           This variable conditionally defines "HASSETSERVENT" if
           setservent() is available.

       "dsetserventr"
           From dsetserventr.U:

           This variable conditionally defines the "HASSETSERVENTR" symbol,
           which indicates to the C program that the setserventr() routine is
           available.

       "dsetsid"
           From dsetsid.U:

           This variable conditionally defines "HASSETSID" if setsid() is
           available to set the process group "ID".

       "dsetvbuf"
           From dsetvbuf.U:

           This variable conditionally defines the "HASSETVBUF" symbol, which
           indicates to the C program that the setvbuf() routine is available
           to change buffering on an open stdio stream.

       "dsfio"
           From dsfio.U:

           This variable conditionally defines the "USESFIO" symbol, and
           indicates whether sfio is available (and should be used).

       "dshm"
           From dshm.U:

           This variable conditionally defines the "HASSHM" symbol, which
           indicates that the entire shm*(2) library is present.

       "dshmat"
           From dshmat.U:

           This variable conditionally defines the "HASSHMAT" symbol, which
           indicates to the C program that the shmat() routine is available.

       "dshmatprototype"
           From dshmat.U:

           This variable conditionally defines the "HASSHMATPROTOTYPE"
           symbol, which indicates that sys/shm.h has a prototype for shmat.

       "dshmctl"
           From dshmctl.U:

           This variable conditionally defines the "HASSHMCTL" symbol, which
           indicates to the C program that the shmctl() routine is available.

       "dshmdt"
           From dshmdt.U:

           This variable conditionally defines the "HASSHMDT" symbol, which
           indicates to the C program that the shmdt() routine is available.

       "dshmget"
           From dshmget.U:

           This variable conditionally defines the "HASSHMGET" symbol, which
           indicates to the C program that the shmget() routine is available.

       "dsigaction"
           From dsigaction.U:

           This variable conditionally defines the "HASSIGACTION" symbol,
           which indicates that the Vr4 sigaction() routine is available.

       "dsignbit"
           From dsignbit.U:

           This variable conditionally defines the "HASSIGNBIT" symbol, which
           indicates to the C program that the signbit() routine is available
           and safe to use with perl's intern "NV" type.

       "dsigprocmask"
           From dsigprocmask.U:

           This variable conditionally defines "HASSIGPROCMASK" if
           sigprocmask() is available to examine or change the signal mask of
           the calling process.

       "dsigsetjmp"
           From dsigsetjmp.U:

           This variable conditionally defines the "HASSIGSETJMP" symbol,
           which indicates that the sigsetjmp() routine is available to call
           setjmp() and optionally save the process's signal mask.

       "dsin6scopeid"
           From dsocket.U:

           This variable conditionally defines the HASSIN6SCOPEID symbol,
           which indicates that a struct sockaddrin6 structure has the
           sin6scopeid member.

       "dsitearch"
           From sitearch.U:

           This variable conditionally defines "SITEARCH" to hold the pathname
           of architecture-dependent library files for $package.  If $sitearch
           is the same as $archlib, then this is set to undef.

       "dsnprintf"
           From dsnprintf.U:

           This variable conditionally defines the "HASSNPRINTF" symbol,
           which indicates to the C program that the snprintf () library
           function is available.

       "dsockaddrin6"
           From dsocket.U:

           This variable conditionally defines the HASSOCKADDRIN6 symbol,
           which indicates the availability of a struct sockaddrin6.

       "dsockaddrsalen"
           From dsocket.U:

           This variable conditionally defines the "HASSOCKADDRSALEN"
           symbol, which indicates that a struct sockaddr structure has the
           salen member.

       "dsockatmark"
           From dsockatmark.U:

           This variable conditionally defines the "HASSOCKATMARK" symbol,
           which indicates to the C program that the sockatmark() routine is
           available.

       "dsockatmarkproto"
           From dsockatmarkproto.U:

           This variable conditionally defines the "HASSOCKATMARKPROTO"
           symbol, which indicates to the C program that the system provides a
           prototype for the sockatmark() function.  Otherwise, it is up to
           the program to supply one.

       "dsocket"
           From dsocket.U:

           This variable conditionally defines "HASSOCKET", which indicates
           that the "BSD" socket interface is supported.

       "dsocklent"
           From dsocklent.U:

           This symbol will be defined if the C compiler supports socklent.

       "dsockpair"
           From dsocket.U:

           This variable conditionally defines the "HASSOCKETPAIR" symbol,
           which indicates that the "BSD" socketpair() is supported.

       "dsocks5init"
           From dsocks5init.U:

           This variable conditionally defines the HASSOCKS5INIT symbol,
           which indicates to the C program that the socks5init() routine is
           available.

       "dsprintfreturnsstrlen"
           From dsprintflen.U:

           This variable defines whether sprintf returns the length of the
           string (as per the "ANSI" spec). Some C libraries retain
           compatibility with pre-"ANSI" C and return a pointer to the passed
           in buffer; for these this variable will be undef.

       "dsqrtl"
           From dsqrtl.U:

           This variable conditionally defines the "HASSQRTL" symbol, which
           indicates to the C program that the sqrtl() routine is available.

       "dsrand48r"
           From dsrand48r.U:

           This variable conditionally defines the HASSRAND48R symbol, which
           indicates to the C program that the srand48r() routine is
           available.

       "dsrandomr"
           From dsrandomr.U:

           This variable conditionally defines the "HASSRANDOMR" symbol,
           which indicates to the C program that the srandomr() routine is
           available.

       "dsresgproto"
           From dsresgproto.U:

           This variable conditionally defines the "HASSETRESGIDPROTO"
           symbol, which indicates to the C program that the system provides a
           prototype for the setresgid() function.  Otherwise, it is up to the
           program to supply one.

       "dsresuproto"
           From dsresuproto.U:

           This variable conditionally defines the "HASSETRESUIDPROTO"
           symbol, which indicates to the C program that the system provides a
           prototype for the setresuid() function.  Otherwise, it is up to the
           program to supply one.

       "dstatblks"
           From dstatblks.U:

           This variable conditionally defines "USESTATBLOCKS" if this
           system has a stat structure declaring stblksize and stblocks.

       "dstatfsfflags"
           From dstatfsfflags.U:

           This variable conditionally defines the "HASSTRUCTSTATFSFFLAGS"
           symbol, which indicates to struct statfs from has fflags member.
           This kind of struct statfs is coming from sys/mount.h ("BSD"), not
           from sys/statfs.h ("SYSV").

       "dstatfss"
           From dstatfss.U:

           This variable conditionally defines the "HASSTRUCTSTATFS" symbol,
           which indicates that the struct statfs is supported.

       "dstaticinline"
           From dstaticinline.U:

           This variable conditionally defines the "HASSTATICINLINE" symbol,
           which indicates that the C compiler supports C99-style static
           inline.  That is, the function can't be called from another
           translation unit.

       "dstatvfs"
           From dstatvfs.U:

           This variable conditionally defines the "HASSTATVFS" symbol, which
           indicates to the C program that the statvfs() routine is available.

       "dstdiocntlval"
           From dstdstdio.U:

           This variable conditionally defines "STDIOCNTLVALUE" if the
           "FILEcnt" macro can be used as an lvalue.

       "dstdioptrlval"
           From dstdstdio.U:

           This variable conditionally defines "STDIOPTRLVALUE" if the
           "FILEptr" macro can be used as an lvalue.

       "dstdioptrlvalnochangecnt"
           From dstdstdio.U:

           This symbol is defined if using the "FILEptr" macro as an lvalue
           to increase the pointer by n leaves Filecnt(fp) unchanged.

       "dstdioptrlvalsetscnt"
           From dstdstdio.U:

           This symbol is defined if using the "FILEptr" macro as an lvalue
           to increase the pointer by n has the side effect of decreasing the
           value of Filecnt(fp) by n.

       "dstdiostreamarray"
           From stdiostreams.U:

           This variable tells whether there is an array holding the stdio
           streams.

       "dstdiobase"
           From dstdstdio.U:

           This variable conditionally defines "USESTDIOBASE" if this system
           has a "FILE" structure declaring a usable base field (or
           equivalent) in stdio.h.

       "dstdstdio"
           From dstdstdio.U:

           This variable conditionally defines "USESTDIOPTR" if this system
           has a "FILE" structure declaring usable ptr and cnt fields (or
           equivalent) in stdio.h.

       "dstrchr"
           From dstrchr.U:

           This variable conditionally defines "HASSTRCHR" if strchr() and
           strrchr() are available for string searching.

       "dstrcoll"
           From dstrcoll.U:

           This variable conditionally defines "HASSTRCOLL" if strcoll() is
           available to compare strings using collating information.

       "dstrctcpy"
           From dstrctcpy.U:

           This variable conditionally defines the "USESTRUCTCOPY" symbol,
           which indicates to the C program that this C compiler knows how to
           copy structures.

       "dstrerrm"
           From dstrerror.U:

           This variable holds what Strerrr is defined as to translate an
           error code condition into an error message string. It could be
           "strerror" or a more "complex" macro emulating strrror with
           syserrlist[], or the "unknown" string when both strerror and
           syserrlist are missing.

       "dstrerror"
           From dstrerror.U:

           This variable conditionally defines "HASSTRERROR" if strerror() is
           available to translate error numbers to strings.

       "dstrerrorr"
           From dstrerrorr.U:

           This variable conditionally defines the "HASSTRERRORR" symbol,
           which indicates to the C program that the strerrorr() routine is
           available.

       "dstrftime"
           From dstrftime.U:

           This variable conditionally defines the "HASSTRFTIME" symbol,
           which indicates to the C program that the strftime() routine is
           available.

       "dstrlcat"
           From dstrlcat.U:

           This variable conditionally defines the "HASSTRLCAT" symbol, which
           indicates to the C program that the strlcat () routine is
           available.

       "dstrlcpy"
           From dstrlcpy.U:

           This variable conditionally defines the "HASSTRLCPY" symbol, which
           indicates to the C program that the strlcpy () routine is
           available.

       "dstrtod"
           From dstrtod.U:

           This variable conditionally defines the "HASSTRTOD" symbol, which
           indicates to the C program that the strtod() routine is available
           to provide better numeric string conversion than atof().

       "dstrtol"
           From dstrtol.U:

           This variable conditionally defines the "HASSTRTOL" symbol, which
           indicates to the C program that the strtol() routine is available
           to provide better numeric string conversion than atoi() and
           friends.

       "dstrtold"
           From dstrtold.U:

           This variable conditionally defines the "HASSTRTOLD" symbol, which
           indicates to the C program that the strtold() routine is available.

       "dstrtoll"
           From dstrtoll.U:

           This variable conditionally defines the "HASSTRTOLL" symbol, which
           indicates to the C program that the strtoll() routine is available.

       "dstrtoq"
           From dstrtoq.U:

           This variable conditionally defines the "HASSTRTOQ" symbol, which
           indicates to the C program that the strtoq() routine is available.

       "dstrtoul"
           From dstrtoul.U:

           This variable conditionally defines the "HASSTRTOUL" symbol, which
           indicates to the C program that the strtoul() routine is available
           to provide conversion of strings to unsigned long.

       "dstrtoull"
           From dstrtoull.U:

           This variable conditionally defines the "HASSTRTOULL" symbol,
           which indicates to the C program that the strtoull() routine is
           available.

       "dstrtouq"
           From dstrtouq.U:

           This variable conditionally defines the "HASSTRTOUQ" symbol, which
           indicates to the C program that the strtouq() routine is available.

       "dstrxfrm"
           From dstrxfrm.U:

           This variable conditionally defines "HASSTRXFRM" if strxfrm() is
           available to transform strings.

       "dsuidsafe"
           From ddosuid.U:

           This variable conditionally defines "SETUIDSCRIPTSARESECURENOW"
           if setuid scripts can be secure.  This test looks in /dev/fd/.

       "dsymlink"
           From dsymlink.U:

           This variable conditionally defines the "HASSYMLINK" symbol, which
           indicates to the C program that the symlink() routine is available
           to create symbolic links.

       "dsyscall"
           From dsyscall.U:

           This variable conditionally defines "HASSYSCALL" if syscall() is
           available call arbitrary system calls.

       "dsyscallproto"
           From dsyscallproto.U:

           This variable conditionally defines the "HASSYSCALLPROTO" symbol,
           which indicates to the C program that the system provides a
           prototype for the syscall() function.  Otherwise, it is up to the
           program to supply one.

       "dsysconf"
           From dsysconf.U:

           This variable conditionally defines the "HASSYSCONF" symbol, which
           indicates to the C program that the sysconf() routine is available
           to determine system related limits and options.

       "dsysernlst"
           From dstrerror.U:

           This variable conditionally defines "HASSYSERRNOLIST" if
           syserrnolist[] is available to translate error numbers to the
           symbolic name.

       "dsyserrlst"
           From dstrerror.U:

           This variable conditionally defines "HASSYSERRLIST" if
           syserrlist[] is available to translate error numbers to strings.

       "dsystem"
           From dsystem.U:

           This variable conditionally defines "HASSYSTEM" if system() is
           available to issue a shell command.

       "dtcgetpgrp"
           From dtcgtpgrp.U:

           This variable conditionally defines the "HASTCGETPGRP" symbol,
           which indicates to the C program that the tcgetpgrp() routine is
           available.  to get foreground process group "ID".

       "dtcsetpgrp"
           From dtcstpgrp.U:

           This variable conditionally defines the "HASTCSETPGRP" symbol,
           which indicates to the C program that the tcsetpgrp() routine is
           available to set foreground process group "ID".

       "dtelldir"
           From dreaddir.U:

           This variable conditionally defines "HASTELLDIR" if telldir() is
           available.

       "dtelldirproto"
           From dtelldirproto.U:

           This variable conditionally defines the "HASTELLDIRPROTO" symbol,
           which indicates to the C program that the system provides a
           prototype for the telldir() function.  Otherwise, it is up to the
           program to supply one.

       "dtime"
           From dtime.U:

           This variable conditionally defines the "HASTIME" symbol, which
           indicates that the time() routine exists.  The time() routine is
           normally provided on "UNIX" systems.

       "dtimegm"
           From dtimegm.U:

           This variable conditionally defines the "HASTIMEGM" symbol, which
           indicates to the C program that the timegm () routine is available.

       "dtimes"
           From dtimes.U:

           This variable conditionally defines the "HASTIMES" symbol, which
           indicates that the times() routine exists.  The times() routine is
           normally provided on "UNIX" systems. You may have to include
           .

       "dtmtmgmtoff"
           From itime.U:

           This variable conditionally defines "HASTMTMGMTOFF", which
           indicates indicates to the C program that the struct tm has the
           tmgmtoff field.

       "dtmtmzone"
           From itime.U:

           This variable conditionally defines "HASTMTMZONE", which
           indicates indicates to the C program that the struct tm has the
           tmzone field.

       "dtmpnamr"
           From dtmpnamr.U:

           This variable conditionally defines the "HASTMPNAMR" symbol,
           which indicates to the C program that the tmpnamr() routine is
           available.

       "dtruncate"
           From dtruncate.U:

           This variable conditionally defines "HASTRUNCATE" if truncate() is
           available to truncate files.

       "dttynamer"
           From dttynamer.U:

           This variable conditionally defines the "HASTTYNAMER" symbol,
           which indicates to the C program that the ttynamer() routine is
           available.

       "dtzname"
           From dtzname.U:

           This variable conditionally defines "HASTZNAME" if tzname[] is
           available to access timezone names.

       "du32align"
           From du32align.U:

           This variable tells whether you must access character data through
           U32-aligned pointers.

       "dualarm"
           From dualarm.U:

           This variable conditionally defines the "HASUALARM" symbol, which
           indicates to the C program that the ualarm() routine is available.

       "dumask"
           From dumask.U:

           This variable conditionally defines the "HASUMASK" symbol, which
           indicates to the C program that the umask() routine is available.
           to set and get the value of the file creation mask.

       "duname"
           From dgethname.U:

           This variable conditionally defines the "HASUNAME" symbol, which
           indicates to the C program that the uname() routine may be used to
           derive the host name.

       "dunionsemun"
           From dunionsemun.U:

           This variable conditionally defines "HASUNIONSEMUN" if the union
           semun is defined by including .

       "dunordered"
           From dunordered.U:

           This variable conditionally defines the "HASUNORDERED" symbol,
           which indicates to the C program that the unordered() routine is
           available.

       "dunsetenv"
           From dunsetenv.U:

           This variable conditionally defines the "HASUNSETENV" symbol,
           which indicates to the C program that the unsetenv () routine is
           available.

       "dusleep"
           From dusleep.U:

           This variable conditionally defines "HASUSLEEP" if usleep() is
           available to do high granularity sleeps.

       "dusleepproto"
           From dusleepproto.U:

           This variable conditionally defines the "HASUSLEEPPROTO" symbol,
           which indicates to the C program that the system provides a
           prototype for the usleep() function.  Otherwise, it is up to the
           program to supply one.

       "dustat"
           From dustat.U:

           This variable conditionally defines "HASUSTAT" if ustat() is
           available to query file system statistics by devt.

       "dvendorarch"
           From vendorarch.U:

           This variable conditionally defined "PERLVENDORARCH".

       "dvendorbin"
           From vendorbin.U:

           This variable conditionally defines "PERLVENDORBIN".

       "dvendorlib"
           From vendorlib.U:

           This variable conditionally defines "PERLVENDORLIB".

       "dvendorscript"
           From vendorscript.U:

           This variable conditionally defines "PERLVENDORSCRIPT".

       "dvfork"
           From dvfork.U:

           This variable conditionally defines the "HASVFORK" symbol, which
           indicates the vfork() routine is available.

       "dvoidclosedir"
           From dclosedir.U:

           This variable conditionally defines "VOIDCLOSEDIR" if closedir()
           does not return a value.

       "dvoidsig"
           From dvoidsig.U:

           This variable conditionally defines "VOIDSIG" if this system
           declares "void (*signal(...))()" in signal.h.  The old way was to
           declare it as "int (*signal(...))()".

       "dvoidtty"
           From isysioctl.U:

           This variable conditionally defines "USEIOCNOTTY" to indicate that
           the ioctl() call with "TIOCNOTTY" should be used to void tty
           association.  Otherwise (on "USG" probably), it is enough to close
           the standard file descriptors and do a setpgrp().

       "dvolatile"
           From dvolatile.U:

           This variable conditionally defines the "HASVOLATILE" symbol, which
           indicates to the C program that this C compiler knows about the
           volatile declaration.

       "dvprintf"
           From dvprintf.U:

           This variable conditionally defines the "HASVPRINTF" symbol, which
           indicates to the C program that the vprintf() routine is available
           to printf with a pointer to an argument list.

       "dvsnprintf"
           From dsnprintf.U:

           This variable conditionally defines the "HASVSNPRINTF" symbol,
           which indicates to the C program that the vsnprintf () library
           function is available.

       "dwait4"
           From dwait4.U:

           This variable conditionally defines the HASWAIT4 symbol, which
           indicates the wait4() routine is available.

       "dwaitpid"
           From dwaitpid.U:

           This variable conditionally defines "HASWAITPID" if waitpid() is
           available to wait for child process.

       "dwcstombs"
           From dwcstombs.U:

           This variable conditionally defines the "HASWCSTOMBS" symbol,
           which indicates to the C program that the wcstombs() routine is
           available to convert wide character strings to multibyte strings.

       "dwctomb"
           From dwctomb.U:

           This variable conditionally defines the "HASWCTOMB" symbol, which
           indicates to the C program that the wctomb() routine is available
           to convert a wide character to a multibyte.

       "dwritev"
           From dwritev.U:

           This variable conditionally defines the "HASWRITEV" symbol, which
           indicates to the C program that the writev() routine is available.

       "dxenix"
           From Guess.U:

           This variable conditionally defines the symbol "XENIX", which
           alerts the C program that it runs under Xenix.

       "date"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the date program.  After Configure runs, the
           value is reset to a plain "date" and is not useful.

       "dbhashtype"
           From idb.U:

           This variable contains the type of the hash structure element in
           the  header file.  In older versions of "DB", it was int,
           while in newer ones it is uint32t.

       "dbprefixtype"
           From idb.U:

           This variable contains the type of the prefix structure element in
           the  header file.  In older versions of "DB", it was int,
           while in newer ones it is sizet.

       "dbversionmajor"
           From idb.U:

           This variable contains the major version number of Berkeley "DB"
           found in the  header file.

       "dbversionminor"
           From idb.U:

           This variable contains the minor version number of Berkeley "DB"
           found in the  header file.  For "DB" version 1 this is always
           0.

       "dbversionpatch"
           From idb.U:

           This variable contains the patch version number of Berkeley "DB"
           found in the  header file.  For "DB" version 1 this is always
           0.

       "defvoidused"
           From voidflags.U:

           This variable contains the default value of the "VOIDUSED" symbol
           (15).

       "direntrytype"
           From idirent.U:

           This symbol is set to "struct direct" or "struct dirent" depending
           on whether dirent is available or not. You should use this pseudo
           type to portably declare your directory entries.

       "dlext"
           From dlext.U:

           This variable contains the extension that is to be used for the
           dynamically loaded modules that perl generaties.

       "dlsrc"
           From dlsrc.U:

           This variable contains the name of the dynamic loading file that
           will be used with the package.

       "doublesize"
           From doublesize.U:

           This variable contains the value of the "DOUBLESIZE" symbol, which
           indicates to the C program how many bytes there are in a double.

       "drand01"
           From randfunc.U:

           Indicates the macro to be used to generate normalized random
           numbers.  Uses randfunc, often divided by (double) (((unsigned
           long) 1 << randbits)) in order to normalize the result.  In C
           programs, the macro "Drand01" is mapped to drand01.

       "drand48rproto"
           From ddrand48r.U:

           This variable encodes the prototype of drand48r.  It is zero if
           ddrand48r is undef, and one of the "REENTRANTPROTOTABC" macros
           of reentr.h if ddrand48r is defined.

       "dtrace"
           From usedtrace.U:

           This variable holds the location of the dtrace executable.

       "dynamicext"
           From Extensions.U:

           This variable holds a list of "XS" extension files we want to link
           dynamically into the package.  It is used by Makefile.

   e
       "eagain"
           From nblockio.U:

           This variable bears the symbolic errno code set by read() when no
           data is present on the file and non-blocking I/O was enabled
           (otherwise, read() blocks naturally).

       "ebcdic"
           From ebcdic.U:

           This variable conditionally defines "EBCDIC" if this system uses
           "EBCDIC" encoding.  Among other things, this means that the
           character ranges are not contiguous.  See trnl.U

       "echo"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the echo program.  After Configure runs, the
           value is reset to a plain "echo" and is not useful.

       "egrep"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the egrep program.  After Configure runs, the
           value is reset to a plain "egrep" and is not useful.

       "emacs"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "endgrentrproto"
           From dendgrentr.U:

           This variable encodes the prototype of endgrentr.  It is zero if
           dendgrentr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dendgrentr is defined.

       "endhostentrproto"
           From dendhostentr.U:

           This variable encodes the prototype of endhostentr.  It is zero if
           dendhostentr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dendhostentr is defined.

       "endnetentrproto"
           From dendnetentr.U:

           This variable encodes the prototype of endnetentr.  It is zero if
           dendnetentr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dendnetentr is defined.

       "endprotoentrproto"
           From dendprotoentr.U:

           This variable encodes the prototype of endprotoentr.  It is zero
           if dendprotoentr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dendprotoentr is defined.

       "endpwentrproto"
           From dendpwentr.U:

           This variable encodes the prototype of endpwentr.  It is zero if
           dendpwentr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dendpwentr is defined.

       "endserventrproto"
           From dendserventr.U:

           This variable encodes the prototype of endserventr.  It is zero if
           dendserventr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dendserventr is defined.

       "eunicefix"
           From Init.U:

           When running under Eunice this variable contains a command which
           will convert a shell script to the proper form of text file for it
           to be executable by the shell.  On other systems it is a no-op.

       "exeext"
           From Unix.U:

           This is an old synonym for exe.

       "expr"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the expr program.  After Configure runs, the
           value is reset to a plain "expr" and is not useful.

       "extensions"
           From Extensions.U:

           This variable holds a list of all extension files (both "XS" and
           non-xs linked into the package.  It is propagated to Config.pm and
           is typically used to test whether a particular extension is
           available.

       "externC"
           From Csym.U:

           "ANSI" C requires "extern" where C++ requires 'extern "C"'. This
           variable can be used in Configure to do the right thing.

       "extras"
           From Extras.U:

           This variable holds a list of extra modules to install.

   f
       "fflushall"
           From fflushall.U:

           This symbol, if defined, tells that to flush all pending stdio
           output one must loop through all the stdio file handles stored in
           an array and fflush them.  Note that if fflushNULL is defined,
           fflushall will not even be probed for and will be left undefined.

       "fflushNULL"
           From fflushall.U:

           This symbol, if defined, tells that fflush("NULL") does flush all
           pending stdio output.

       "find"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "firstmakefile"
           From Unix.U:

           This variable defines the first file searched by make.  On unix, it
           is makefile (then Makefile).  On case-insensitive systems, it might
           be something else.  This is only used to deal with convoluted make
           depend tricks.

       "flex"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "fpossize"
           From fpossize.U:

           This variable contains the size of a fpostype in bytes.

       "fpostype"
           From fpostype.U:

           This variable defines Fpost to be something like fpost, long,
           uint, or whatever type is used to declare file positions in libc.

       "freetype"
           From mallocsrc.U:

           This variable contains the return type of free().  It is usually
           void, but occasionally int.

       "from"
           From Cross.U:

           This variable contains the command used by Configure to copy files
           from the target host.  Useful and available only during Perl build.
           The string ":" if not cross-compiling.

       "fullar"
           From Locar.U:

           This variable contains the full pathname to "ar", whether or not
           the user has specified "portability".  This is only used in the
           Makefile.SH.

       "fullcsh"
           From dcsh.U:

           This variable contains the full pathname to "csh", whether or not
           the user has specified "portability".  This is only used in the
           compiled C program, and we assume that all systems which can share
           this executable will have the same full pathname to csh.

       "fullsed"
           From Locsed.U:

           This variable contains the full pathname to "sed", whether or not
           the user has specified "portability".  This is only used in the
           compiled C program, and we assume that all systems which can share
           this executable will have the same full pathname to sed.

   g
       "gccansipedantic"
           From gccvers.U:

           If "GNU" cc (gcc) is used, this variable will enable (if set) the
           -ansi and -pedantic ccflags for building core files (through cflags
           script). (See Porting/pumpkin.pod for full description).

       "gccosandvers"
           From gccvers.U:

           If "GNU" cc (gcc) is used, this variable holds the operating system
           and version used to compile gcc.  It is set to '' if not gcc, or if
           nothing useful can be parsed as the os version.

       "gccversion"
           From gccvers.U:

           If "GNU" cc (gcc) is used, this variable holds 1 or 2 to indicate
           whether the compiler is version 1 or 2.  This is used in setting
           some of the default cflags.  It is set to '' if not gcc.

       "getgrentrproto"
           From dgetgrentr.U:

           This variable encodes the prototype of getgrentr.  It is zero if
           dgetgrentr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dgetgrentr is defined.

       "getgrgidrproto"
           From dgetgrgidr.U:

           This variable encodes the prototype of getgrgidr.  It is zero if
           dgetgrgidr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dgetgrgidr is defined.

       "getgrnamrproto"
           From dgetgrnamr.U:

           This variable encodes the prototype of getgrnamr.  It is zero if
           dgetgrnamr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dgetgrnamr is defined.

       "gethostbyaddrrproto"
           From dgethostbyaddrr.U:

           This variable encodes the prototype of gethostbyaddrr.  It is zero
           if dgethostbyaddrr is undef, and one of the
           "REENTRANTPROTOTABC" macros of reentr.h if dgethostbyaddrr is
           defined.

       "gethostbynamerproto"
           From dgethostbynamer.U:

           This variable encodes the prototype of gethostbynamer.  It is zero
           if dgethostbynamer is undef, and one of the
           "REENTRANTPROTOTABC" macros of reentr.h if dgethostbynamer is
           defined.

       "gethostentrproto"
           From dgethostentr.U:

           This variable encodes the prototype of gethostentr.  It is zero if
           dgethostentr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dgethostentr is defined.

       "getloginrproto"
           From dgetloginr.U:

           This variable encodes the prototype of getloginr.  It is zero if
           dgetloginr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dgetloginr is defined.

       "getnetbyaddrrproto"
           From dgetnetbyaddrr.U:

           This variable encodes the prototype of getnetbyaddrr.  It is zero
           if dgetnetbyaddrr is undef, and one of the
           "REENTRANTPROTOTABC" macros of reentr.h if dgetnetbyaddrr is
           defined.

       "getnetbynamerproto"
           From dgetnetbynamer.U:

           This variable encodes the prototype of getnetbynamer.  It is zero
           if dgetnetbynamer is undef, and one of the
           "REENTRANTPROTOTABC" macros of reentr.h if dgetnetbynamer is
           defined.

       "getnetentrproto"
           From dgetnetentr.U:

           This variable encodes the prototype of getnetentr.  It is zero if
           dgetnetentr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dgetnetentr is defined.

       "getprotobynamerproto"
           From dgetprotobynamer.U:

           This variable encodes the prototype of getprotobynamer.  It is
           zero if dgetprotobynamer is undef, and one of the
           "REENTRANTPROTOTABC" macros of reentr.h if dgetprotobynamer is
           defined.

       "getprotobynumberrproto"
           From dgetprotobynumberr.U:

           This variable encodes the prototype of getprotobynumberr.  It is
           zero if dgetprotobynumberr is undef, and one of the
           "REENTRANTPROTOTABC" macros of reentr.h if dgetprotobynumberr
           is defined.

       "getprotoentrproto"
           From dgetprotoentr.U:

           This variable encodes the prototype of getprotoentr.  It is zero
           if dgetprotoentr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dgetprotoentr is defined.

       "getpwentrproto"
           From dgetpwentr.U:

           This variable encodes the prototype of getpwentr.  It is zero if
           dgetpwentr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dgetpwentr is defined.

       "getpwnamrproto"
           From dgetpwnamr.U:

           This variable encodes the prototype of getpwnamr.  It is zero if
           dgetpwnamr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dgetpwnamr is defined.

       "getpwuidrproto"
           From dgetpwuidr.U:

           This variable encodes the prototype of getpwuidr.  It is zero if
           dgetpwuidr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dgetpwuidr is defined.

       "getservbynamerproto"
           From dgetservbynamer.U:

           This variable encodes the prototype of getservbynamer.  It is zero
           if dgetservbynamer is undef, and one of the
           "REENTRANTPROTOTABC" macros of reentr.h if dgetservbynamer is
           defined.

       "getservbyportrproto"
           From dgetservbyportr.U:

           This variable encodes the prototype of getservbyportr.  It is zero
           if dgetservbyportr is undef, and one of the
           "REENTRANTPROTOTABC" macros of reentr.h if dgetservbyportr is
           defined.

       "getserventrproto"
           From dgetserventr.U:

           This variable encodes the prototype of getserventr.  It is zero if
           dgetserventr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dgetserventr is defined.

       "getspnamrproto"
           From dgetspnamr.U:

           This variable encodes the prototype of getspnamr.  It is zero if
           dgetspnamr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dgetspnamr is defined.

       "gidformat"
           From gidf.U:

           This variable contains the format string used for printing a Gidt.

       "gidsign"
           From gidsign.U:

           This variable contains the signedness of a gidtype.  1 for
           unsigned, -1 for signed.

       "gidsize"
           From gidsize.U:

           This variable contains the size of a gidtype in bytes.

       "gidtype"
           From gidtype.U:

           This variable defines Gidt to be something like gidt, int,
           ushort, or whatever type is used to declare the return type of
           getgid().  Typically, it is the type of group ids in the kernel.

       "glibpth"
           From libpth.U:

           This variable holds the general path (space-separated) used to find
           libraries.  It may contain directories that do not exist on this
           platform, libpth is the cleaned-up version.

       "gmake"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the gmake program.  After Configure runs, the
           value is reset to a plain "gmake" and is not useful.

       "gmtimerproto"
           From dgmtimer.U:

           This variable encodes the prototype of gmtimer.  It is zero if
           dgmtimer is undef, and one of the "REENTRANTPROTOTABC" macros
           of reentr.h if dgmtimer is defined.

       "gnulibcversion"
           From dgnulibc.U:

           This variable contains the version number of the "GNU" C library.
           It is usually something like 2.2.5.  It is a plain '' if this is
           not the "GNU" C library, or if the version is unknown.

       "grep"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the grep program.  After Configure runs, the
           value is reset to a plain "grep" and is not useful.

       "groupcat"
           From nis.U:

           This variable contains a command that produces the text of the
           /etc/group file.  This is normally "cat /etc/group", but can be
           "ypcat group" when "NIS" is used.  On some systems, such as os390,
           there may be no equivalent command, in which case this variable is
           unset.

       "groupstype"
           From groupstype.U:

           This variable defines Groupst to be something like gidt, int,
           ushort, or whatever type is used for the second argument to
           getgroups() and setgroups().  Usually, this is the same as gidtype
           (gidt), but sometimes it isn't.

       "gzip"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the gzip program.  After Configure runs, the
           value is reset to a plain "gzip" and is not useful.

   h
       "hfcntl"
           From hfcntl.U:

           This is variable gets set in various places to tell ifcntl that
            should be included.

       "hsysfile"
           From hsysfile.U:

           This is variable gets set in various places to tell isysfile that
            should be included.

       "hint"
           From Oldconfig.U:

           Gives the type of hints used for previous answers. May be one of
           "default", "recommended" or "previous".

       "hostcat"
           From nis.U:

           This variable contains a command that produces the text of the
           /etc/hosts file.  This is normally "cat /etc/hosts", but can be
           "ypcat hosts" when "NIS" is used.  On some systems, such as os390,
           there may be no equivalent command, in which case this variable is
           unset.

       "html1dir"
           From html1dir.U:

           This variable contains the name of the directory in which html
           source pages are to be put.  This directory is for pages that
           describe whole programs, not libraries or modules.  It is intended
           to correspond roughly to section 1 of the Unix manuals.

       "html1direxp"
           From html1dir.U:

           This variable is the same as the html1dir variable, but is filename
           expanded at configuration time, for convenient use in makefiles.

       "html3dir"
           From html3dir.U:

           This variable contains the name of the directory in which html
           source pages are to be put.  This directory is for pages that
           describe libraries or modules.  It is intended to correspond
           roughly to section 3 of the Unix manuals.

       "html3direxp"
           From html3dir.U:

           This variable is the same as the html3dir variable, but is filename
           expanded at configuration time, for convenient use in makefiles.

   i
       "i16size"
           From perlxv.U:

           This variable is the size of an I16 in bytes.

       "i16type"
           From perlxv.U:

           This variable contains the C type used for Perl's I16.

       "i32size"
           From perlxv.U:

           This variable is the size of an I32 in bytes.

       "i32type"
           From perlxv.U:

           This variable contains the C type used for Perl's I32.

       "i64size"
           From perlxv.U:

           This variable is the size of an I64 in bytes.

       "i64type"
           From perlxv.U:

           This variable contains the C type used for Perl's I64.

       "i8size"
           From perlxv.U:

           This variable is the size of an I8 in bytes.

       "i8type"
           From perlxv.U:

           This variable contains the C type used for Perl's I8.

       "iarpainet"
           From iarpainet.U:

           This variable conditionally defines the "IARPAINET" symbol, and
           indicates whether a C program should include .

       "iassert"
           From iassert.U:

           This variable conditionally defines the "IASSERT" symbol, which
           indicates to the C program that  exists and could be
           included.

       "ibsdioctl"
           From isysioctl.U:

           This variable conditionally defines the "ISYSBSDIOCTL" symbol,
           which indicates to the C program that  exists and
           should be included.

       "icrypt"
           From icrypt.U:

           This variable conditionally defines the "ICRYPT" symbol, and
           indicates whether a C program should include .

       "idb"
           From idb.U:

           This variable conditionally defines the "IDB" symbol, and
           indicates whether a C program may include Berkeley's "DB" include
           file .

       "idbm"
           From idbm.U:

           This variable conditionally defines the "IDBM" symbol, which
           indicates to the C program that  exists and should be
           included.

       "idirent"
           From idirent.U:

           This variable conditionally defines "IDIRENT", which indicates to
           the C program that it should include .

       "idld"
           From idld.U:

           This variable conditionally defines the "IDLD" symbol, which
           indicates to the C program that  ("GNU" dynamic loading)
           exists and should be included.

       "idlfcn"
           From idlfcn.U:

           This variable conditionally defines the "IDLFCN" symbol, which
           indicates to the C program that  exists and should be
           included.

       "ifcntl"
           From ifcntl.U:

           This variable controls the value of "IFCNTL" (which tells the C
           program to include ).

       "ifloat"
           From ifloat.U:

           This variable conditionally defines the "IFLOAT" symbol, and
           indicates whether a C program may include  to get symbols
           like "DBLMAX" or "DBLMIN", i.e. machine dependent floating point
           values.

       "ifp"
           From ifp.U:

           This variable conditionally defines the "IFP" symbol, and
           indicates whether a C program should include .

       "ifpclass"
           From ifpclass.U:

           This variable conditionally defines the "IFPCLASS" symbol, and
           indicates whether a C program should include .

       "igdbm"
           From igdbm.U:

           This variable conditionally defines the "IGDBM" symbol, which
           indicates to the C program that  exists and should be
           included.

       "igdbmndbm"
           From indbm.U:

           This variable conditionally defines the "IGDBMNDBM" symbol, which
           indicates to the C program that  exists and should be
           included.  This is the location of the ndbm.h compatibility file in
           Debian 4.0.

       "igdbmndbm"
           From indbm.U:

           This variable conditionally defines the "IGDBMNDBM" symbol, which
           indicates to the C program that  exists and should be
           included.  This was the location of the ndbm.h compatibility file
           in RedHat 7.1.

       "igrp"
           From igrp.U:

           This variable conditionally defines the "IGRP" symbol, and
           indicates whether a C program should include .

       "iieeefp"
           From iieeefp.U:

           This variable conditionally defines the "IIEEEFP" symbol, and
           indicates whether a C program should include .

       "iinttypes"
           From iinttypes.U:

           This variable conditionally defines the "IINTTYPES" symbol, and
           indicates whether a C program should include .

       "ilanginfo"
           From ilanginfo.U:

           This variable conditionally defines the "ILANGINFO" symbol, and
           indicates whether a C program should include .

       "ilibutil"
           From ilibutil.U:

           This variable conditionally defines the "ILIBUTIL" symbol, and
           indicates whether a C program should include .

       "ilimits"
           From ilimits.U:

           This variable conditionally defines the "ILIMITS" symbol, and
           indicates whether a C program may include  to get symbols
           like "WORDBIT" and friends.

       "ilocale"
           From ilocale.U:

           This variable conditionally defines the "ILOCALE" symbol, and
           indicates whether a C program should include .

       "imachcthr"
           From imachcthr.U:

           This variable conditionally defines the "IMACHCTHREADS" symbol,
           and indicates whether a C program should include .

       "imalloc"
           From imalloc.U:

           This variable conditionally defines the "IMALLOC" symbol, and
           indicates whether a C program should include .

       "imallocmalloc"
           From imallocmalloc.U:

           This variable conditionally defines the "IMALLOCMALLOC" symbol,
           and indicates whether a C program should include .

       "imath"
           From imath.U:

           This variable conditionally defines the "IMATH" symbol, and
           indicates whether a C program may include .

       "imemory"
           From imemory.U:

           This variable conditionally defines the "IMEMORY" symbol, and
           indicates whether a C program should include .

       "imntent"
           From imntent.U:

           This variable conditionally defines the "IMNTENT" symbol, and
           indicates whether a C program should include .

       "indbm"
           From indbm.U:

           This variable conditionally defines the "INDBM" symbol, which
           indicates to the C program that  exists and should be
           included.

       "inetdb"
           From inetdb.U:

           This variable conditionally defines the "INETDB" symbol, and
           indicates whether a C program should include .

       "ineterrno"
           From ineterrno.U:

           This variable conditionally defines the "INETERRNO" symbol, which
           indicates to the C program that  exists and should be
           included.

       "inetinettcp"
           From inetinettcp.U:

           This variable conditionally defines the "INETINETTCP" symbol, and
           indicates whether a C program should include .

       "iniin"
           From iniin.U:

           This variable conditionally defines "INETINETIN", which indicates
           to the C program that it should include . Otherwise,
           you may try .

       "ipoll"
           From ipoll.U:

           This variable conditionally defines the "IPOLL" symbol, and
           indicates whether a C program should include .

       "iprot"
           From iprot.U:

           This variable conditionally defines the "IPROT" symbol, and
           indicates whether a C program should include .

       "ipthread"
           From ipthread.U:

           This variable conditionally defines the "IPTHREAD" symbol, and
           indicates whether a C program should include .

       "ipwd"
           From ipwd.U:

           This variable conditionally defines "IPWD", which indicates to the
           C program that it should include .

       "irpcsvcdbm"
           From idbm.U:

           This variable conditionally defines the "IRPCSVCDBM" symbol,
           which indicates to the C program that  exists and
           should be included.  Some System V systems might need this instead
           of .

       "isfio"
           From isfio.U:

           This variable conditionally defines the "ISFIO" symbol, and
           indicates whether a C program should include .

       "isgtty"
           From itermio.U:

           This variable conditionally defines the "ISGTTY" symbol, which
           indicates to the C program that it should include  rather
           than .

       "ishadow"
           From ishadow.U:

           This variable conditionally defines the "ISHADOW" symbol, and
           indicates whether a C program should include .

       "isocks"
           From isocks.U:

           This variable conditionally defines the "ISOCKS" symbol, and
           indicates whether a C program should include .

       "istdarg"
           From ivarhdr.U:

           This variable conditionally defines the "ISTDARG" symbol, which
           indicates to the C program that  exists and should be
           included.

       "istdbool"
           From istdbool.U:

           This variable conditionally defines the "ISTDBOOL" symbol, which
           indicates to the C program that  exists and should be
           included.

       "istddef"
           From istddef.U:

           This variable conditionally defines the "ISTDDEF" symbol, which
           indicates to the C program that  exists and should be
           included.

       "istdlib"
           From istdlib.U:

           This variable conditionally defines the "ISTDLIB" symbol, which
           indicates to the C program that  exists and should be
           included.

       "istring"
           From istring.U:

           This variable conditionally defines the "ISTRING" symbol, which
           indicates that  should be included rather than
           .

       "isunmath"
           From isunmath.U:

           This variable conditionally defines the "ISUNMATH" symbol, and
           indicates whether a C program should include .

       "isysaccess"
           From isysaccess.U:

           This variable conditionally defines the "ISYSACCESS" symbol, and
           indicates whether a C program should include .

       "isysdir"
           From isysdir.U:

           This variable conditionally defines the "ISYSDIR" symbol, and
           indicates whether a C program should include .

       "isysfile"
           From isysfile.U:

           This variable conditionally defines the "ISYSFILE" symbol, and
           indicates whether a C program should include  to get
           "ROK" and friends.

       "isysfilio"
           From isysioctl.U:

           This variable conditionally defines the "ISYSFILIO" symbol, which
           indicates to the C program that  exists and should be
           included in preference to .

       "isysin"
           From iniin.U:

           This variable conditionally defines "ISYSIN", which indicates to
           the C program that it should include  instead of
           .

       "isysioctl"
           From isysioctl.U:

           This variable conditionally defines the "ISYSIOCTL" symbol, which
           indicates to the C program that  exists and should be
           included.

       "isyslog"
           From isyslog.U:

           This variable conditionally defines the "ISYSLOG" symbol, and
           indicates whether a C program should include .

       "isysmman"
           From isysmman.U:

           This variable conditionally defines the "ISYSMMAN" symbol, and
           indicates whether a C program should include .

       "isysmode"
           From isysmode.U:

           This variable conditionally defines the "ISYSMODE" symbol, and
           indicates whether a C program should include .

       "isysmount"
           From isysmount.U:

           This variable conditionally defines the "ISYSMOUNT" symbol, and
           indicates whether a C program should include .

       "isysndir"
           From isysndir.U:

           This variable conditionally defines the "ISYSNDIR" symbol, and
           indicates whether a C program should include .

       "isysparam"
           From isysparam.U:

           This variable conditionally defines the "ISYSPARAM" symbol, and
           indicates whether a C program should include .

       "isyspoll"
           From isyspoll.U:

           This variable conditionally defines the "ISYSPOLL" symbol, which
           indicates to the C program that it should include .

       "isysresrc"
           From isysresrc.U:

           This variable conditionally defines the "ISYSRESOURCE" symbol,
           and indicates whether a C program should include .

       "isyssecrt"
           From isyssecrt.U:

           This variable conditionally defines the "ISYSSECURITY" symbol,
           and indicates whether a C program should include .

       "isysselct"
           From isysselct.U:

           This variable conditionally defines "ISYSSELECT", which indicates
           to the C program that it should include  in order to
           get the definition of struct timeval.

       "isyssockio"
           From isysioctl.U:

           This variable conditionally defines "ISYSSOCKIO" to indicate to
           the C program that socket ioctl codes may be found in
            instead of .

       "isysstat"
           From isysstat.U:

           This variable conditionally defines the "ISYSSTAT" symbol, and
           indicates whether a C program should include .

       "isysstatfs"
           From isysstatfs.U:

           This variable conditionally defines the "ISYSSTATFS" symbol, and
           indicates whether a C program should include .

       "isysstatvfs"
           From isysstatvfs.U:

           This variable conditionally defines the "ISYSSTATVFS" symbol, and
           indicates whether a C program should include .

       "isystime"
           From itime.U:

           This variable conditionally defines "ISYSTIME", which indicates
           to the C program that it should include .

       "isystimek"
           From itime.U:

           This variable conditionally defines "ISYSTIMEKERNEL", which
           indicates to the C program that it should include  with
           "KERNEL" defined.

       "isystimes"
           From isystimes.U:

           This variable conditionally defines the "ISYSTIMES" symbol, and
           indicates whether a C program should include .

       "isystypes"
           From isystypes.U:

           This variable conditionally defines the "ISYSTYPES" symbol, and
           indicates whether a C program should include .

       "isysuio"
           From isysuio.U:

           This variable conditionally defines the "ISYSUIO" symbol, and
           indicates whether a C program should include .

       "isysun"
           From isysun.U:

           This variable conditionally defines "ISYSUN", which indicates to
           the C program that it should include  to get "UNIX"
           domain socket definitions.

       "isysutsname"
           From isysutsname.U:

           This variable conditionally defines the "ISYSUTSNAME" symbol, and
           indicates whether a C program should include .

       "isysvfs"
           From isysvfs.U:

           This variable conditionally defines the "ISYSVFS" symbol, and
           indicates whether a C program should include .

       "isyswait"
           From isyswait.U:

           This variable conditionally defines "ISYSWAIT", which indicates
           to the C program that it should include .

       "itermio"
           From itermio.U:

           This variable conditionally defines the "ITERMIO" symbol, which
           indicates to the C program that it should include  rather
           than .

       "itermios"
           From itermio.U:

           This variable conditionally defines the "ITERMIOS" symbol, which
           indicates to the C program that the "POSIX"  file is to
           be included.

       "itime"
           From itime.U:

           This variable conditionally defines "ITIME", which indicates to
           the C program that it should include .

       "iunistd"
           From iunistd.U:

           This variable conditionally defines the "IUNISTD" symbol, and
           indicates whether a C program should include .

       "iustat"
           From iustat.U:

           This variable conditionally defines the "IUSTAT" symbol, and
           indicates whether a C program should include .

       "iutime"
           From iutime.U:

           This variable conditionally defines the "IUTIME" symbol, and
           indicates whether a C program should include .

       "ivalues"
           From ivalues.U:

           This variable conditionally defines the "IVALUES" symbol, and
           indicates whether a C program may include  to get symbols
           like "MAXLONG" and friends.

       "ivarargs"
           From ivarhdr.U:

           This variable conditionally defines "IVARARGS", which indicates to
           the C program that it should include .

       "ivarhdr"
           From ivarhdr.U:

           Contains the name of the header to be included to get vadcl
           definition.  Typically one of varargs.h or stdarg.h.

       "ivfork"
           From ivfork.U:

           This variable conditionally defines the "IVFORK" symbol, and
           indicates whether a C program should include vfork.h.

       "ignoreversionedsolibs"
           From libs.U:

           This variable should be non-empty if non-versioned shared libraries
           (libfoo.so.x.y) are to be ignored (because they cannot be linked
           against).

       "incversionlist"
           From incversionlist.U:

           This variable specifies the list of subdirectories in over which
           perl.c:incpush() and lib/lib.pm will automatically search when
           adding directories to @"INC".  The elements in the list are
           separated by spaces.  This is only useful if you have a perl
           library directory tree structured like the default one.  See
           "INSTALL" for how this works.  The versioned siteperl directory
           was introduced in 5.005, so that is the lowest possible value.

           This list includes architecture-dependent directories back to
           version $apiversionstring (e.g. 5.5.640) and architecture-
           independent directories all the way back to 5.005.

       "incversionlistinit"
           From incversionlist.U:

           This variable holds the same list as incversionlist, but each
           item is enclosed in double quotes and separated by commas, suitable
           for use in the "PERLINCVERSIONLIST" initialization.

       "incpath"
           From usrinc.U:

           This variable must precede the normal include path to get the right
           one, as in $incpath/usr/include or $incpath/usr/lib.  Value can be
           "" or /bsd43 on mips.

       "inews"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "initialinstalllocation"
           From bin.U:

           When userelocatableinc is true, this variable holds the location
           that make install should copy the perl binary to, with all the run-
           time relocatable paths calculated from this at install time.  When
           used, it is initialised to the original value of binexp, and then
           binexp is set to .../, as the other binaries are found relative to
           the perl binary.

       "installarchlib"
           From archlib.U:

           This variable is really the same as archlibexp but may differ on
           those systems using "AFS". For extra portability, only this
           variable should be used in makefiles.

       "installbin"
           From bin.U:

           This variable is the same as binexp unless "AFS" is running in
           which case the user is explicitly prompted for it. This variable
           should always be used in your makefiles for maximum portability.

       "installhtml1dir"
           From html1dir.U:

           This variable is really the same as html1direxp, unless you are
           using a different installprefix.  For extra portability, you should
           only use this variable within your makefiles.

       "installhtml3dir"
           From html3dir.U:

           This variable is really the same as html3direxp, unless you are
           using a different installprefix.  For extra portability, you should
           only use this variable within your makefiles.

       "installman1dir"
           From man1dir.U:

           This variable is really the same as man1direxp, unless you are
           using "AFS" in which case it points to the read/write location
           whereas man1direxp only points to the read-only access location.
           For extra portability, you should only use this variable within
           your makefiles.

       "installman3dir"
           From man3dir.U:

           This variable is really the same as man3direxp, unless you are
           using "AFS" in which case it points to the read/write location
           whereas man3direxp only points to the read-only access location.
           For extra portability, you should only use this variable within
           your makefiles.

       "installprefix"
           From installprefix.U:

           This variable holds the name of the directory below which "make
           install" will install the package.  For most users, this is the
           same as prefix.  However, it is useful for installing the software
           into a different (usually temporary) location after which it can be
           bundled up and moved somehow to the final location specified by
           prefix.

       "installprefixexp"
           From installprefix.U:

           This variable holds the full absolute path of installprefix with
           all ~-expansion done.

       "installprivlib"
           From privlib.U:

           This variable is really the same as privlibexp but may differ on
           those systems using "AFS". For extra portability, only this
           variable should be used in makefiles.

       "installscript"
           From scriptdir.U:

           This variable is usually the same as scriptdirexp, unless you are
           on a system running "AFS", in which case they may differ slightly.
           You should always use this variable within your makefiles for
           portability.

       "installsitearch"
           From sitearch.U:

           This variable is really the same as sitearchexp but may differ on
           those systems using "AFS". For extra portability, only this
           variable should be used in makefiles.

       "installsitebin"
           From sitebin.U:

           This variable is usually the same as sitebinexp, unless you are on
           a system running "AFS", in which case they may differ slightly. You
           should always use this variable within your makefiles for
           portability.

       "installsitehtml1dir"
           From sitehtml1dir.U:

           This variable is really the same as sitehtml1direxp, unless you are
           using "AFS" in which case it points to the read/write location
           whereas html1direxp only points to the read-only access location.
           For extra portability, you should only use this variable within
           your makefiles.

       "installsitehtml3dir"
           From sitehtml3dir.U:

           This variable is really the same as sitehtml3direxp, unless you are
           using "AFS" in which case it points to the read/write location
           whereas html3direxp only points to the read-only access location.
           For extra portability, you should only use this variable within
           your makefiles.

       "installsitelib"
           From sitelib.U:

           This variable is really the same as sitelibexp but may differ on
           those systems using "AFS". For extra portability, only this
           variable should be used in makefiles.

       "installsiteman1dir"
           From siteman1dir.U:

           This variable is really the same as siteman1direxp, unless you are
           using "AFS" in which case it points to the read/write location
           whereas man1direxp only points to the read-only access location.
           For extra portability, you should only use this variable within
           your makefiles.

       "installsiteman3dir"
           From siteman3dir.U:

           This variable is really the same as siteman3direxp, unless you are
           using "AFS" in which case it points to the read/write location
           whereas man3direxp only points to the read-only access location.
           For extra portability, you should only use this variable within
           your makefiles.

       "installsitescript"
           From sitescript.U:

           This variable is usually the same as sitescriptexp, unless you are
           on a system running "AFS", in which case they may differ slightly.
           You should always use this variable within your makefiles for
           portability.

       "installstyle"
           From installstyle.U:

           This variable describes the "style" of the perl installation.  This
           is intended to be useful for tools that need to manipulate entire
           perl distributions.  Perl itself doesn't use this to find its
           libraries  the library directories are stored directly in
           Config.pm.  Currently, there are only two styles:  "lib" and
           lib/perl5.  The default library locations (e.g. privlib, sitelib)
           are either $prefix/lib or $prefix/lib/perl5.  The former is useful
           if $prefix is a directory dedicated to perl (e.g. /opt/perl), while
           the latter is useful if $prefix is shared by many packages, e.g. if
           $prefix=/usr/local.

           Unfortunately, while this "style" variable is used to set defaults
           for all three directory hierarchies (core, vendor, and site), there
           is no guarantee that the same style is actually appropriate for all
           those directories.  For example, $prefix might be /opt/perl, but
           $siteprefix might be /usr/local.  (Perhaps, in retrospect, the
           "lib" style should never have been supported, but it did seem like
           a nice idea at the time.)

           The situation is even less clear for tools such as MakeMaker that
           can be used to install additional modules into non-standard places.
           For example, if a user intends to install a module into a private
           directory (perhaps by setting "PREFIX" on the Makefile.PL command
           line), then there is no reason to assume that the Configure-time
           $installstyle setting will be relevant for that "PREFIX".

           This may later be extended to include other information, so be
           careful with pattern-matching on the results.

           For compatibility with perl5.005 and earlier, the default setting
           is based on whether or not $prefix contains the string "perl".

       "installusrbinperl"
           From instubperl.U:

           This variable tells whether Perl should be installed also as
           /usr/bin/perl in addition to $installbin/perl

       "installvendorarch"
           From vendorarch.U:

           This variable is really the same as vendorarchexp but may differ on
           those systems using "AFS". For extra portability, only this
           variable should be used in makefiles.

       "installvendorbin"
           From vendorbin.U:

           This variable is really the same as vendorbinexp but may differ on
           those systems using "AFS". For extra portability, only this
           variable should be used in makefiles.

       "installvendorhtml1dir"
           From vendorhtml1dir.U:

           This variable is really the same as vendorhtml1direxp but may
           differ on those systems using "AFS". For extra portability, only
           this variable should be used in makefiles.

       "installvendorhtml3dir"
           From vendorhtml3dir.U:

           This variable is really the same as vendorhtml3direxp but may
           differ on those systems using "AFS". For extra portability, only
           this variable should be used in makefiles.

       "installvendorlib"
           From vendorlib.U:

           This variable is really the same as vendorlibexp but may differ on
           those systems using "AFS". For extra portability, only this
           variable should be used in makefiles.

       "installvendorman1dir"
           From vendorman1dir.U:

           This variable is really the same as vendorman1direxp but may differ
           on those systems using "AFS". For extra portability, only this
           variable should be used in makefiles.

       "installvendorman3dir"
           From vendorman3dir.U:

           This variable is really the same as vendorman3direxp but may differ
           on those systems using "AFS". For extra portability, only this
           variable should be used in makefiles.

       "installvendorscript"
           From vendorscript.U:

           This variable is really the same as vendorscriptexp but may differ
           on those systems using "AFS". For extra portability, only this
           variable should be used in makefiles.

       "intsize"
           From intsize.U:

           This variable contains the value of the "INTSIZE" symbol, which
           indicates to the C program how many bytes there are in an int.

       "issymlink"
           From issymlink.U:

           This variable holds the test command to test for a symbolic link
           (if they are supported).  Typical values include "test -h" and
           "test -L".

       "ivdformat"
           From perlxvf.U:

           This variable contains the format string used for printing a Perl
           "IV" as a signed decimal integer.

       "ivsize"
           From perlxv.U:

           This variable is the size of an "IV" in bytes.

       "ivtype"
           From perlxv.U:

           This variable contains the C type used for Perl's "IV".

   k
       "knownextensions"
           From Extensions.U:

           This variable holds a list of all "XS" extensions included in the
           package.

       "ksh"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

   l
       "ld"
           From dlsrc.U:

           This variable indicates the program to be used to link libraries
           for dynamic loading.  On some systems, it is "ld".  On "ELF"
           systems, it should be $cc.  Mostly, we'll try to respect the hint
           file setting.

       "ldcanscript"
           From dlsrc.U:

           This variable shows if the loader accepts scripts in the form of
           -Wl,version-script=ld.script. This is currently only supported
           for "GNU" ld on "ELF" in dynamic loading builds.

       "lddlflags"
           From dlsrc.U:

           This variable contains any special flags that might need to be
           passed to $ld to create a shared library suitable for dynamic
           loading.  It is up to the makefile to use it.  For hpux, it should
           be "-b".  For sunos 4.1, it is empty.

       "ldflags"
           From ccflags.U:

           This variable contains any additional C loader flags desired by the
           user.  It is up to the Makefile to use this.

       "ldflagsuselargefiles"
           From uselfs.U:

           This variable contains the loader flags needed by large file builds
           and added to ldflags by hints files.

       "ldlibpthname"
           From libperl.U:

           This variable holds the name of the shared library search path,
           often "LDLIBRARYPATH".  To get an empty string, the hints file
           must set this to "none".

       "less"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the less program.  After Configure runs, the
           value is reset to a plain "less" and is not useful.

       "libext"
           From Unix.U:

           This is an old synonym for a.

       "libc"
           From libc.U:

           This variable contains the location of the C library.

       "libperl"
           From libperl.U:

           The perl executable is obtained by linking perlmain.c with libperl,
           any static extensions (usually just DynaLoader), and any other
           libraries needed on this system.  libperl is usually libperl.a, but
           can also be libperl.so.xxx if the user wishes to build a perl
           executable with a shared library.

       "libpth"
           From libpth.U:

           This variable holds the general path (space-separated) used to find
           libraries. It is intended to be used by other units.

       "libs"
           From libs.U:

           This variable holds the additional libraries we want to use.  It is
           up to the Makefile to deal with it.  The list can be empty.

       "libsdirs"
           From libs.U:

           This variable holds the directory names aka dirnames of the
           libraries we found and accepted, duplicates are removed.

       "libsfiles"
           From libs.U:

           This variable holds the filenames aka basenames of the libraries we
           found and accepted.

       "libsfound"
           From libs.U:

           This variable holds the full pathnames of the libraries we found
           and accepted.

       "libspath"
           From libs.U:

           This variable holds the directory names probed for libraries.

       "libswanted"
           From Myinit.U:

           This variable holds a list of all the libraries we want to search.
           The order is chosen to pick up the c library ahead of ucb or bsd
           libraries for SVR4.

       "libswanteduselargefiles"
           From uselfs.U:

           This variable contains the libraries needed by large file builds
           and added to ldflags by hints files.  It is a space separated list
           of the library names without the "lib" prefix or any suffix, just
           like libswanted..

       "line"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "lint"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "lkflags"
           From ccflags.U:

           This variable contains any additional C partial linker flags
           desired by the user.  It is up to the Makefile to use this.

       "ln"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the ln program.  After Configure runs, the
           value is reset to a plain "ln" and is not useful.

       "lns"
           From lns.U:

           This variable holds the name of the command to make symbolic links
           (if they are supported).  It can be used in the Makefile. It is
           either "ln -s" or "ln"

       "localtimerproto"
           From dlocaltimer.U:

           This variable encodes the prototype of localtimer.  It is zero if
           dlocaltimer is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dlocaltimer is defined.

       "locincpth"
           From ccflags.U:

           This variable contains a list of additional directories to be
           searched by the compiler.  The appropriate "-I" directives will be
           added to ccflags.  This is intended to simplify setting local
           directories from the Configure command line.  It's not much, but it
           parallels the loclibpth stuff in libpth.U.

       "loclibpth"
           From libpth.U:

           This variable holds the paths (space-separated) used to find local
           libraries.  It is prepended to libpth, and is intended to be easily
           set from the command line.

       "longdblsize"
           From dlongdbl.U:

           This variable contains the value of the "LONGDOUBLESIZE" symbol,
           which indicates to the C program how many bytes there are in a long
           double, if this system supports long doubles.

       "longlongsize"
           From dlonglong.U:

           This variable contains the value of the "LONGLONGSIZE" symbol,
           which indicates to the C program how many bytes there are in a long
           long, if this system supports long long.

       "longsize"
           From intsize.U:

           This variable contains the value of the "LONGSIZE" symbol, which
           indicates to the C program how many bytes there are in a long.

       "lp"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "lpr"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "ls"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the ls program.  After Configure runs, the
           value is reset to a plain "ls" and is not useful.

       "lseeksize"
           From lseektype.U:

           This variable defines lseektype to be something like offt, long,
           or whatever type is used to declare lseek offset's type in the
           kernel (which also appears to be lseek's return type).

       "lseektype"
           From lseektype.U:

           This variable defines lseektype to be something like offt, long,
           or whatever type is used to declare lseek offset's type in the
           kernel (which also appears to be lseek's return type).

   m
       "mad"
           From mad.U:

           This variable indicates that the Misc Attribute Definition code is
           to be compiled.

       "madlyh"
           From mad.U:

           If the Misc Attribute Decoration is to be compiled, this variable
           is set to the name of the extra header files to be used, else it is
           ''

       "madlyobj"
           From mad.U:

           If the Misc Attribute Decoration is to be compiled, this variable
           is set to the name of the extra object files to be used, else it is
           ''

       "madlysrc"
           From mad.U:

           If the Misc Attribute Decoration is to be compiled, this variable
           is set to the name of the extra C source files to be used, else it
           is ''

       "mail"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "mailx"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "make"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the make program.  After Configure runs, the
           value is reset to a plain "make" and is not useful.

       "makesetmake"
           From make.U:

           Some versions of "make" set the variable "MAKE".  Others do not.
           This variable contains the string to be included in Makefile.SH so
           that "MAKE" is set if needed, and not if not needed.  Possible
           values are:

           makesetmake="#"        # If your make program handles this for
           you,

           makesetmake="MAKE=$make"    # if it doesn't.

           This uses a comment character so that we can distinguish a "set"
           value (from a previous config.sh or Configure "-D" option) from an
           uncomputed value.

       "mallocobj"
           From mallocsrc.U:

           This variable contains the name of the malloc.o that this package
           generates, if that malloc.o is preferred over the system malloc.
           Otherwise the value is null.  This variable is intended for
           generating Makefiles.  See mallocsrc.

       "mallocsrc"
           From mallocsrc.U:

           This variable contains the name of the malloc.c that comes with the
           package, if that malloc.c is preferred over the system malloc.
           Otherwise the value is null.  This variable is intended for
           generating Makefiles.

       "malloctype"
           From mallocsrc.U:

           This variable contains the kind of ptr returned by malloc and
           realloc.

       "man1dir"
           From man1dir.U:

           This variable contains the name of the directory in which manual
           source pages are to be put.  It is the responsibility of the
           Makefile.SH to get the value of this into the proper command.  You
           must be prepared to do the ~name expansion yourself.

       "man1direxp"
           From man1dir.U:

           This variable is the same as the man1dir variable, but is filename
           expanded at configuration time, for convenient use in makefiles.

       "man1ext"
           From man1dir.U:

           This variable contains the extension that the manual page should
           have: one of "n", "l", or 1.  The Makefile must supply the ..  See
           man1dir.

       "man3dir"
           From man3dir.U:

           This variable contains the name of the directory in which manual
           source pages are to be put.  It is the responsibility of the
           Makefile.SH to get the value of this into the proper command.  You
           must be prepared to do the ~name expansion yourself.

       "man3direxp"
           From man3dir.U:

           This variable is the same as the man3dir variable, but is filename
           expanded at configuration time, for convenient use in makefiles.

       "man3ext"
           From man3dir.U:

           This variable contains the extension that the manual page should
           have: one of "n", "l", or 3.  The Makefile must supply the ..  See
           man3dir.

       "mipstype"
           From usrinc.U:

           This variable holds the environment type for the mips system.
           Possible values are "BSD 4.3" and "System V".

       "mistrustnm"
           From Csym.U:

           This variable can be used to establish a fallthrough for the cases
           where nm fails to find a symbol.  If usenm is false or usenm is
           true and mistrustnm is false, this variable has no effect.  If
           usenm is true and mistrustnm is "compile", a test program will be
           compiled to try to find any symbol that can't be located via nm
           lookup.  If mistrustnm is "run", the test program will be run as
           well as being compiled.

       "mkdir"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the mkdir program.  After Configure runs, the
           value is reset to a plain "mkdir" and is not useful.

       "mmaptype"
           From dmmap.U:

           This symbol contains the type of pointer returned by mmap() (and
           simultaneously the type of the first argument).  It can be "void *"
           or "caddrt".

       "modetype"
           From modetype.U:

           This variable defines modetype to be something like modet, int,
           unsigned short, or whatever type is used to declare file modes for
           system calls.

       "more"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the more program.  After Configure runs, the
           value is reset to a plain "more" and is not useful.

       "multiarch"
           From multiarch.U:

           This variable conditionally defines the "MULTIARCH" symbol which
           signifies the presence of multiplatform files.  This is normally
           set by hints files.

       "mv"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "myarchname"
           From archname.U:

           This variable holds the architecture name computed by Configure in
           a previous run. It is not intended to be perused by any user and
           should never be set in a hint file.

       "mydomain"
           From myhostname.U:

           This variable contains the eventual value of the "MYDOMAIN" symbol,
           which is the domain of the host the program is going to run on.
           The domain must be appended to myhostname to form a complete host
           name.  The dot comes with mydomain, and need not be supplied by the
           program.

       "myhostname"
           From myhostname.U:

           This variable contains the eventual value of the "MYHOSTNAME"
           symbol, which is the name of the host the program is going to run
           on.  The domain is not kept with hostname, but must be gotten from
           mydomain.  The dot comes with mydomain, and need not be supplied by
           the program.

       "myuname"
           From Oldconfig.U:

           The output of "uname -a" if available, otherwise the hostname. On
           Xenix, pseudo variables assignments in the output are stripped,
           thank you. The whole thing is then lower-cased.

   n
       "n" From n.U:

           This variable contains the "-n" flag if that is what causes the
           echo command to suppress newline.  Otherwise it is null.  Correct
           usage is $echo $n "prompt for a question: $c".

       "needvacopy"
           From needvacopy.U:

           This symbol, if defined, indicates that the system stores the
           variable argument list datatype, valist, in a format that cannot
           be copied by simple assignment, so that some other means must be
           used when copying is required.  As such systems vary in their
           provision (or non-provision) of copying mechanisms, handy.h defines
           a platform- "independent" macro, Perlvacopy(src, dst), to do the
           job.

       "netdbhlentype"
           From netdbtype.U:

           This variable holds the type used for the 2nd argument to
           gethostbyaddr().  Usually, this is int or sizet or unsigned.  This
           is only useful if you have gethostbyaddr(), naturally.

       "netdbhosttype"
           From netdbtype.U:

           This variable holds the type used for the 1st argument to
           gethostbyaddr().  Usually, this is char * or void *,  possibly with
           or without a const prefix.  This is only useful if you have
           gethostbyaddr(), naturally.

       "netdbnametype"
           From netdbtype.U:

           This variable holds the type used for the argument to
           gethostbyname().  Usually, this is char * or const char *.  This is
           only useful if you have gethostbyname(), naturally.

       "netdbnettype"
           From netdbtype.U:

           This variable holds the type used for the 1st argument to
           getnetbyaddr().  Usually, this is int or long.  This is only useful
           if you have getnetbyaddr(), naturally.

       "nm"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the nm program.  After Configure runs, the
           value is reset to a plain "nm" and is not useful.

       "nmopt"
           From usenm.U:

           This variable holds the options that may be necessary for nm.

       "nmsoopt"
           From usenm.U:

           This variable holds the options that may be necessary for nm to
           work on a shared library but that can not be used on an archive
           library.  Currently, this is only used by Linux, where nm dynamic
           is *required* to get symbols from an "ELF" library which has been
           stripped, but nm dynamic is *fatal* on an archive library.  Maybe
           Linux should just always set usenm=false.

       "nonxsext"
           From Extensions.U:

           This variable holds a list of all non-xs extensions included in the
           package.  All of them will be built.

       "nroff"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the nroff program.  After Configure runs, the
           value is reset to a plain "nroff" and is not useful.

       "nvoverflowsintegersat"
           From perlxv.U:

           This variable gives the largest integer value that NVs can hold as
           a constant floating point expression.  If it could not be
           determined, it holds the value 0.

       "nvpreservesuvbits"
           From perlxv.U:

           This variable indicates how many of bits type uvtype a variable
           nvtype can preserve.

       "nveformat"
           From perlxvf.U:

           This variable contains the format string used for printing a Perl
           "NV" using %e-ish floating point format.

       "nvEUformat"
           From perlxvf.U:

           This variable contains the format string used for printing a Perl
           "NV" using %E-ish floating point format.

       "nvfformat"
           From perlxvf.U:

           This variable confains the format string used for printing a Perl
           "NV" using %f-ish floating point format.

       "nvFUformat"
           From perlxvf.U:

           This variable confains the format string used for printing a Perl
           "NV" using %F-ish floating point format.

       "nvgformat"
           From perlxvf.U:

           This variable contains the format string used for printing a Perl
           "NV" using %g-ish floating point format.

       "nvGUformat"
           From perlxvf.U:

           This variable contains the format string used for printing a Perl
           "NV" using %G-ish floating point format.

       "nvsize"
           From perlxv.U:

           This variable is the size of an "NV" in bytes.

       "nvtype"
           From perlxv.U:

           This variable contains the C type used for Perl's "NV".

   o
       "ononblock"
           From nblockio.U:

           This variable bears the symbol value to be used during open() or
           fcntl() to turn on non-blocking I/O for a file descriptor. If you
           wish to switch between blocking and non-blocking, you may try
           ioctl("FIOSNBIO") instead, but that is only supported by some
           devices.

       "objext"
           From Unix.U:

           This is an old synonym for o.

       "oldpthreadcreatejoinable"
           From dpthrattrj.U:

           This variable defines the constant to use for creating joinable
           (aka undetached) pthreads.  Unused if pthread.h defines
           "PTHREADCREATEJOINABLE".  If used, possible values are
           "PTHREADCREATEUNDETACHED" and "UNDETACHED".

       "optimize"
           From ccflags.U:

           This variable contains any optimizer/debugger flag that should be
           used.  It is up to the Makefile to use it.

       "orderlib"
           From orderlib.U:

           This variable is "true" if the components of libraries must be
           ordered (with `lorder $* | tsort`) before placing them in an
           archive.  Set to "false" if ranlib or ar can generate random
           libraries.

       "osname"
           From Oldconfig.U:

           This variable contains the operating system name (e.g. sunos,
           solaris, hpux, etc.).  It can be useful later on for setting
           defaults.  Any spaces are replaced with underscores.  It is set to
           a null string if we can't figure it out.

       "osvers"
           From Oldconfig.U:

           This variable contains the operating system version (e.g.  4.1.3,
           5.2, etc.).  It is primarily used for helping select an appropriate
           hints file, but might be useful elsewhere for setting defaults.  It
           is set to '' if we can't figure it out.  We try to be flexible
           about how much of the version number to keep, e.g. if 4.1.1, 4.1.2,
           and 4.1.3 are essentially the same for this package, hints files
           might just be os4.0 or os4.1, etc., not keeping separate files
           for each little release.

       "otherlibdirs"
           From otherlibdirs.U:

           This variable contains a colon-separated set of paths for the perl
           binary to search for additional library files or modules.  These
           directories will be tacked to the end of @"INC".  Perl will
           automatically search below each path for version- and architecture-
           specific directories.  See incversionlist for more details.  A
           value of " " means "none" and is used to preserve this value for
           the next run through Configure.

   p
       "package"
           From package.U:

           This variable contains the name of the package being constructed.
           It is primarily intended for the use of later Configure units.

       "pager"
           From pager.U:

           This variable contains the name of the preferred pager on the
           system.  Usual values are (the full pathnames of) more, less, pg,
           or cat.

       "passcat"
           From nis.U:

           This variable contains a command that produces the text of the
           /etc/passwd file.  This is normally "cat /etc/passwd", but can be
           "ypcat passwd" when "NIS" is used.  On some systems, such as os390,
           there may be no equivalent command, in which case this variable is
           unset.

       "patchlevel"
           From patchlevel.U:

           The patchlevel level of this package.  The value of patchlevel
           comes from the patchlevel.h file.  In a version number such as
           5.6.1, this is the 6.  In patchlevel.h, this is referred to as
           "PERLVERSION".

       "pathsep"
           From Unix.U:

           This is an old synonym for p in Head.U, the character used to
           separate elements in the command shell search "PATH".

       "perl"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the perl program.  After Configure runs, the
           value is reset to a plain "perl" and is not useful.

       "perl5"
           From perl5.U:

           This variable contains the full path (if any) to a previously
           installed perl5.005 or later suitable for running the script to
           determine incversionlist.

   P
       "PERLAPIREVISION"
           From patchlevel.h:

           This number describes the earliest compatible "PERLREVISION" of
           Perl ("compatibility" here being defined as sufficient binary/"API"
           compatibility to run "XS" code built with the older version).
           Normally this does not change across maintenance releases.  Please
           read the comment in patchlevel.h.

       "PERLAPISUBVERSION"
           From patchlevel.h:

           This number describes the earliest compatible "PERLSUBVERSION" of
           Perl ("compatibility" here being defined as sufficient binary/"API"
           compatibility to run "XS" code built with the older version).
           Normally this does not change across maintenance releases.  Please
           read the comment in patchlevel.h.

       "PERLAPIVERSION"
           From patchlevel.h:

           This number describes the earliest compatible "PERLVERSION" of
           Perl ("compatibility" here being defined as sufficient binary/"API"
           compatibility to run "XS" code built with the older version).
           Normally this does not change across maintenance releases.  Please
           read the comment in patchlevel.h.

       "PERLCONFIGSH"
           From Oldsyms.U:

           This is set to "true" in config.sh so that a shell script sourcing
           config.sh can tell if it has been sourced already.

       "PERLPATCHLEVEL"
           From Oldsyms.U:

           This symbol reflects the patchlevel, if available. Will usually
           come from the .patch file, which is available when the perl source
           tree was fetched with rsync.

       "perlpatchlevel"
           From patchlevel.U:

           This is the Perl patch level, a numeric change identifier, as
           defined by whichever source code maintenance system is used to
           maintain the patches; currently Perforce.  It does not correlate
           with the Perl version numbers or the maintenance versus development
           dichotomy except by also being increasing.

       "PERLREVISION"
           From Oldsyms.U:

           In a Perl version number such as 5.6.2, this is the 5.  This value
           is manually set in patchlevel.h

       "perlstaticinline"
           From dstaticinline.U:

           This variable defines the "PERLSTATICINLINE" symbol to the best-
           guess incantation to use for static inline functions.
           Possibilities include static inline       (c99) static inline
           (gcc -ansi) static inline     ("MSVC") static inline      (older
           "MSVC") static              (c89 compilers)

       "PERLSUBVERSION"
           From Oldsyms.U:

           In a Perl version number such as 5.6.2, this is the 2.  Values
           greater than 50 represent potentially unstable development
           subversions.  This value is manually set in patchlevel.h

       "PERLVERSION"
           From Oldsyms.U:

           In a Perl version number such as 5.6.2, this is the 6.  This value
           is manually set in patchlevel.h

       "perladmin"
           From perladmin.U:

           Electronic mail address of the perl5 administrator.

       "perllibs"
           From End.U:

           The list of libraries needed by Perl only (any libraries needed by
           extensions only will by dropped, if using dynamic loading).

       "perlpath"
           From perlpath.U:

           This variable contains the eventual value of the "PERLPATH" symbol,
           which contains the name of the perl interpreter to be used in shell
           scripts and in the "eval "exec"" idiom.  This variable is not
           necessarily the pathname of the file containing the perl
           interpreter; you must append the executable extension (exe) if it
           is not already present.  Note that Perl code that runs during the
           Perl build process cannot reference this variable, as Perl may not
           have been installed, or even if installed, may be a different
           version of Perl.

       "pg"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the pg program.  After Configure runs, the
           value is reset to a plain "pg" and is not useful.

       "phostname"
           From myhostname.U:

           This variable contains the eventual value of the "PHOSTNAME"
           symbol, which is a command that can be fed to popen() to get the
           host name.  The program should probably not presume that the domain
           is or isn't there already.

       "pidtype"
           From pidtype.U:

           This variable defines "PIDTYPE" to be something like pidt, int,
           ushort, or whatever type is used to declare process ids in the
           kernel.

       "plibpth"
           From libpth.U:

           Holds the private path used by Configure to find out the libraries.
           Its value is prepend to libpth. This variable takes care of special
           machines, like the mips.  Usually, it should be empty.

       "pmake"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "pr"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "prefix"
           From prefix.U:

           This variable holds the name of the directory below which the user
           will install the package.  Usually, this is /usr/local, and
           executables go in /usr/local/bin, library stuff in /usr/local/lib,
           man pages in /usr/local/man, etc.  It is only used to set defaults
           for things in bin.U, mansrc.U, privlib.U, or scriptdir.U.

       "prefixexp"
           From prefix.U:

           This variable holds the full absolute path of the directory below
           which the user will install the package.  Derived from prefix.

       "privlib"
           From privlib.U:

           This variable contains the eventual value of the "PRIVLIB" symbol,
           which is the name of the private library for this package.  It may
           have a ~ on the front. It is up to the makefile to eventually
           create this directory while performing installation (with ~
           substitution).

       "privlibexp"
           From privlib.U:

           This variable is the ~name expanded version of privlib, so that you
           may use it directly in Makefiles or shell scripts.

       "procselfexe"
           From dprocselfexe.U:

           If dprocselfexe is defined, $procselfexe is the filename of the
           symbolic link pointing to the absolute pathname of the executing
           program.

       "prototype"
           From prototype.U:

           This variable holds the eventual value of "CANPROTOTYPE", which
           indicates the C compiler can handle funciton prototypes.

       "ptrsize"
           From ptrsize.U:

           This variable contains the value of the "PTRSIZE" symbol, which
           indicates to the C program how many bytes there are in a pointer.

   q
       "quadkind"
           From quadtype.U:

           This variable, if defined, encodes the type of a quad: 1 = int, 2 =
           long, 3 = long long, 4 = int64t.

       "quadtype"
           From quadtype.U:

           This variable defines Quadt to be something like long, int, long
           long, int64t, or whatever type is used for 64-bit integers.

   r
       "randbits"
           From randfunc.U:

           Indicates how many bits are produced by the function used to
           generate normalized random numbers.

       "randfunc"
           From randfunc.U:

           Indicates the name of the random number function to use.  Values
           include drand48, random, and rand. In C programs, the "Drand01"
           macro is defined to generate uniformly distributed random numbers
           over the range [0., 1.[ (see drand01 and nrand).

       "randomrproto"
           From drandomr.U:

           This variable encodes the prototype of randomr.  It is zero if
           drandomr is undef, and one of the "REENTRANTPROTOTABC" macros
           of reentr.h if drandomr is defined.

       "randseedtype"
           From randfunc.U:

           Indicates the type of the argument of the seedfunc.

       "ranlib"
           From orderlib.U:

           This variable is set to the pathname of the ranlib program, if it
           is needed to generate random libraries.  Set to ":" if ar can
           generate random libraries or if random libraries are not supported

       "rdnodata"
           From nblockio.U:

           This variable holds the return code from read() when no data is
           present. It should be -1, but some systems return 0 when "ONDELAY"
           is used, which is a shame because you cannot make the difference
           between no data and an EOF.. Sigh!

       "readdir64rproto"
           From dreaddir64r.U:

           This variable encodes the prototype of readdir64r.  It is zero if
           dreaddir64r is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dreaddir64r is defined.

       "readdirrproto"
           From dreaddirr.U:

           This variable encodes the prototype of readdirr.  It is zero if
           dreaddirr is undef, and one of the "REENTRANTPROTOTABC" macros
           of reentr.h if dreaddirr is defined.

       "revision"
           From patchlevel.U:

           The value of revision comes from the patchlevel.h file.  In a
           version number such as 5.6.1, this is the 5.  In patchlevel.h, this
           is referred to as "PERLREVISION".

       "rm"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the rm program.  After Configure runs, the
           value is reset to a plain "rm" and is not useful.

       "rmtry"
           From Unix.U:

           This is a cleanup variable for try test programs.  Internal
           Configure use only.

       "rmail"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "run"
           From Cross.U:

           This variable contains the command used by Configure to copy and
           execute a cross-compiled executable in the target host.  Useful and
           available only during Perl build.  Empty string '' if not cross-
           compiling.

       "runnm"
           From usenm.U:

           This variable contains "true" or "false" depending whether the nm
           extraction should be performed or not, according to the value of
           usenm and the flags on the Configure command line.

   s
       "schedyield"
           From dpthready.U:

           This variable defines the way to yield the execution of the current
           thread.

       "scriptdir"
           From scriptdir.U:

           This variable holds the name of the directory in which the user
           wants to put publicly scripts for the package in question.  It is
           either the same directory as for binaries, or a special one that
           can be mounted across different architectures, like /usr/share.
           Programs must be prepared to deal with ~name expansion.

       "scriptdirexp"
           From scriptdir.U:

           This variable is the same as scriptdir, but is filename expanded at
           configuration time, for programs not wanting to bother with it.

       "sed"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the sed program.  After Configure runs, the
           value is reset to a plain "sed" and is not useful.

       "seedfunc"
           From randfunc.U:

           Indicates the random number generating seed function.  Values
           include srand48, srandom, and srand.

       "selectminbits"
           From selectminbits.U:

           This variable holds the minimum number of bits operated by select.
           That is, if you do select(n, ...), how many bits at least will be
           cleared in the masks if some activity is detected.  Usually this is
           either n or 32*ceil(n/32), especially many little-endians do the
           latter.  This is only useful if you have select(), naturally.

       "selecttype"
           From selecttype.U:

           This variable holds the type used for the 2nd, 3rd, and 4th
           arguments to select.  Usually, this is "fdset *", if "HASFDSET"
           is defined, and "int *" otherwise.  This is only useful if you have
           select(), naturally.

       "sendmail"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "setgrentrproto"
           From dsetgrentr.U:

           This variable encodes the prototype of setgrentr.  It is zero if
           dsetgrentr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dsetgrentr is defined.

       "sethostentrproto"
           From dsethostentr.U:

           This variable encodes the prototype of sethostentr.  It is zero if
           dsethostentr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dsethostentr is defined.

       "setlocalerproto"
           From dsetlocaler.U:

           This variable encodes the prototype of setlocaler.  It is zero if
           dsetlocaler is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dsetlocaler is defined.

       "setnetentrproto"
           From dsetnetentr.U:

           This variable encodes the prototype of setnetentr.  It is zero if
           dsetnetentr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dsetnetentr is defined.

       "setprotoentrproto"
           From dsetprotoentr.U:

           This variable encodes the prototype of setprotoentr.  It is zero
           if dsetprotoentr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dsetprotoentr is defined.

       "setpwentrproto"
           From dsetpwentr.U:

           This variable encodes the prototype of setpwentr.  It is zero if
           dsetpwentr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dsetpwentr is defined.

       "setserventrproto"
           From dsetserventr.U:

           This variable encodes the prototype of setserventr.  It is zero if
           dsetserventr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dsetserventr is defined.

       "sGMTIMEmax"
           From timesize.U:

           This variable defines the maximum value of the timet offset that
           the system function gmtime () accepts

       "sGMTIMEmin"
           From timesize.U:

           This variable defines the minimum value of the timet offset that
           the system function gmtime () accepts

       "sh"
           From sh.U:

           This variable contains the full pathname of the shell used on this
           system to execute Bourne shell scripts.  Usually, this will be
           /bin/sh, though it's possible that some systems will have /bin/ksh,
           /bin/pdksh, /bin/ash, /bin/bash, or even something such as
           D:/bin/sh.exe.  This unit comes before Options.U, so you can't set
           sh with a "-D" option, though you can override this (and startsh)
           with "-O -Dsh=/bin/whatever -Dstartsh=whatever"

       "shar"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "sharpbang"
           From spitshell.U:

           This variable contains the string #! if this system supports that
           construct.

       "shmattype"
           From dshmat.U:

           This symbol contains the type of pointer returned by shmat().  It
           can be "void *" or "char *".

       "shortsize"
           From intsize.U:

           This variable contains the value of the "SHORTSIZE" symbol which
           indicates to the C program how many bytes there are in a short.

       "shrpenv"
           From libperl.U:

           If the user builds a shared libperl.so, then we need to tell the
           "perl" executable where it will be able to find the installed
           libperl.so.  One way to do this on some systems is to set the
           environment variable "LDRUNPATH" to the directory that will be
           the final location of the shared libperl.so.  The makefile can use
           this with something like $shrpenv $("CC") -o perl perlmain.o
           $libperl $libs Typical values are shrpenv="env
           "LDRUNPATH"=$archlibexp/"CORE"" or shrpenv='' See the main perl
           Makefile.SH for actual working usage.  Alternatively, we might be
           able to use a command line option such as -R $archlibexp/"CORE"
           (Solaris) or -Wl,-rpath $archlibexp/"CORE" (Linux).

       "shsharp"
           From spitshell.U:

           This variable tells further Configure units whether your sh can
           handle # comments.

       "sigcount"
           From signame.U:

           This variable holds a number larger than the largest valid signal
           number.  This is usually the same as the "NSIG" macro.

       "signame"
           From signame.U:

           This variable holds the signal names, space separated. The leading
           "SIG" in signal name is removed.  A "ZERO" is prepended to the
           list.  This is currently not used, signameinit is used instead.

       "signameinit"
           From signame.U:

           This variable holds the signal names, enclosed in double quotes and
           separated by commas, suitable for use in the "SIGNAME" definition
           below.  A "ZERO" is prepended to the list, and the list is
           terminated with a plain 0.  The leading "SIG" in signal names is
           removed. See signum.

       "signum"
           From signame.U:

           This variable holds the signal numbers, space separated. A "ZERO"
           is prepended to the list (corresponding to the fake "SIGZERO").
           Those numbers correspond to  the value of the signal listed in the
           same place within the signame list.  This is currently not used,
           signuminit is used instead.

       "signuminit"
           From signame.U:

           This variable holds the signal numbers, enclosed in double quotes
           and separated by commas, suitable for use in the "SIGNUM"
           definition below.  A "ZERO" is prepended to the list, and the list
           is terminated with a plain 0.

       "sigsize"
           From signame.U:

           This variable contains the number of elements of the signame and
           signum arrays.

       "signalt"
           From dvoidsig.U:

           This variable holds the type of the signal handler (void or int).

       "sitearch"
           From sitearch.U:

           This variable contains the eventual value of the "SITEARCH" symbol,
           which is the name of the private library for this package.  It may
           have a ~ on the front. It is up to the makefile to eventually
           create this directory while performing installation (with ~
           substitution).  The standard distribution will put nothing in this
           directory.  After perl has been installed, users may install their
           own local architecture-dependent modules in this directory with
           MakeMaker Makefile.PL or equivalent.  See "INSTALL" for details.

       "sitearchexp"
           From sitearch.U:

           This variable is the ~name expanded version of sitearch, so that
           you may use it directly in Makefiles or shell scripts.

       "sitebin"
           From sitebin.U:

           This variable holds the name of the directory in which the user
           wants to put add-on publicly executable files for the package in
           question.  It is most often a local directory such as
           /usr/local/bin. Programs using this variable must be prepared to
           deal with ~name substitution.  The standard distribution will put
           nothing in this directory.  After perl has been installed, users
           may install their own local executables in this directory with
           MakeMaker Makefile.PL or equivalent.  See "INSTALL" for details.

       "sitebinexp"
           From sitebin.U:

           This is the same as the sitebin variable, but is filename expanded
           at configuration time, for use in your makefiles.

       "sitehtml1dir"
           From sitehtml1dir.U:

           This variable contains the name of the directory in which site-
           specific html source pages are to be put.  It is the responsibility
           of the Makefile.SH to get the value of this into the proper
           command.  You must be prepared to do the ~name expansion yourself.
           The standard distribution will put nothing in this directory.
           After perl has been installed, users may install their own local
           html pages in this directory with MakeMaker Makefile.PL or
           equivalent.  See "INSTALL" for details.

       "sitehtml1direxp"
           From sitehtml1dir.U:

           This variable is the same as the sitehtml1dir variable, but is
           filename expanded at configuration time, for convenient use in
           makefiles.

       "sitehtml3dir"
           From sitehtml3dir.U:

           This variable contains the name of the directory in which site-
           specific library html source pages are to be put.  It is the
           responsibility of the Makefile.SH to get the value of this into the
           proper command.  You must be prepared to do the ~name expansion
           yourself.  The standard distribution will put nothing in this
           directory.  After perl has been installed, users may install their
           own local library html pages in this directory with MakeMaker
           Makefile.PL or equivalent.  See "INSTALL" for details.

       "sitehtml3direxp"
           From sitehtml3dir.U:

           This variable is the same as the sitehtml3dir variable, but is
           filename expanded at configuration time, for convenient use in
           makefiles.

       "sitelib"
           From sitelib.U:

           This variable contains the eventual value of the "SITELIB" symbol,
           which is the name of the private library for this package.  It may
           have a ~ on the front. It is up to the makefile to eventually
           create this directory while performing installation (with ~
           substitution).  The standard distribution will put nothing in this
           directory.  After perl has been installed, users may install their
           own local architecture-independent modules in this directory with
           MakeMaker Makefile.PL or equivalent.  See "INSTALL" for details.

       "sitelibstem"
           From sitelib.U:

           This variable is $sitelibexp with any trailing version-specific
           component removed.  The elements in incversionlist
           (incversionlist.U) can be tacked onto this variable to generate a
           list of directories to search.

       "sitelibexp"
           From sitelib.U:

           This variable is the ~name expanded version of sitelib, so that you
           may use it directly in Makefiles or shell scripts.

       "siteman1dir"
           From siteman1dir.U:

           This variable contains the name of the directory in which site-
           specific manual source pages are to be put.  It is the
           responsibility of the Makefile.SH to get the value of this into the
           proper command.  You must be prepared to do the ~name expansion
           yourself.  The standard distribution will put nothing in this
           directory.  After perl has been installed, users may install their
           own local man1 pages in this directory with MakeMaker Makefile.PL
           or equivalent.  See "INSTALL" for details.

       "siteman1direxp"
           From siteman1dir.U:

           This variable is the same as the siteman1dir variable, but is
           filename expanded at configuration time, for convenient use in
           makefiles.

       "siteman3dir"
           From siteman3dir.U:

           This variable contains the name of the directory in which site-
           specific library man source pages are to be put.  It is the
           responsibility of the Makefile.SH to get the value of this into the
           proper command.  You must be prepared to do the ~name expansion
           yourself.  The standard distribution will put nothing in this
           directory.  After perl has been installed, users may install their
           own local man3 pages in this directory with MakeMaker Makefile.PL
           or equivalent.  See "INSTALL" for details.

       "siteman3direxp"
           From siteman3dir.U:

           This variable is the same as the siteman3dir variable, but is
           filename expanded at configuration time, for convenient use in
           makefiles.

       "siteprefix"
           From siteprefix.U:

           This variable holds the full absolute path of the directory below
           which the user will install add-on packages.  See "INSTALL" for
           usage and examples.

       "siteprefixexp"
           From siteprefix.U:

           This variable holds the full absolute path of the directory below
           which the user will install add-on packages.  Derived from
           siteprefix.

       "sitescript"
           From sitescript.U:

           This variable holds the name of the directory in which the user
           wants to put add-on publicly executable files for the package in
           question.  It is most often a local directory such as
           /usr/local/bin. Programs using this variable must be prepared to
           deal with ~name substitution.  The standard distribution will put
           nothing in this directory.  After perl has been installed, users
           may install their own local scripts in this directory with
           MakeMaker Makefile.PL or equivalent.  See "INSTALL" for details.

       "sitescriptexp"
           From sitescript.U:

           This is the same as the sitescript variable, but is filename
           expanded at configuration time, for use in your makefiles.

       "sizesize"
           From sizesize.U:

           This variable contains the size of a sizetype in bytes.

       "sizetype"
           From sizetype.U:

           This variable defines sizetype to be something like sizet,
           unsigned long, or whatever type is used to declare length
           parameters for string functions.

       "sleep"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "sLOCALTIMEmax"
           From timesize.U:

           This variable defines the maximum value of the timet offset that
           the system function localtime () accepts

       "sLOCALTIMEmin"
           From timesize.U:

           This variable defines the minimum value of the timet offset that
           the system function localtime () accepts

       "smail"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "so"
           From so.U:

           This variable holds the extension used to identify shared libraries
           (also known as shared objects) on the system. Usually set to "so".

       "sockethdr"
           From dsocket.U:

           This variable has any cpp "-I" flags needed for socket support.

       "socketlib"
           From dsocket.U:

           This variable has the names of any libraries needed for socket
           support.

       "socksizetype"
           From socksizetype.U:

           This variable holds the type used for the size argument for various
           socket calls like accept.  Usual values include socklent, sizet,
           and int.

       "sort"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the sort program.  After Configure runs, the
           value is reset to a plain "sort" and is not useful.

       "spackage"
           From package.U:

           This variable contains the name of the package being constructed,
           with the first letter uppercased, i.e. suitable for starting
           sentences.

       "spitshell"
           From spitshell.U:

           This variable contains the command necessary to spit out a runnable
           shell on this system.  It is either cat or a grep "-v" for #
           comments.

       "sPRId64"
           From quadfio.U:

           This variable, if defined, contains the string used by stdio to
           format 64-bit decimal numbers (format "d") for output.

       "sPRIeldbl"
           From longdblfio.U:

           This variable, if defined, contains the string used by stdio to
           format long doubles (format "e") for output.

       "sPRIEUldbl"
           From longdblfio.U:

           This variable, if defined, contains the string used by stdio to
           format long doubles (format "E") for output.  The "U" in the name
           is to separate this from sPRIeldbl so that even case-blind systems
           can see the difference.

       "sPRIfldbl"
           From longdblfio.U:

           This variable, if defined, contains the string used by stdio to
           format long doubles (format "f") for output.

       "sPRIFUldbl"
           From longdblfio.U:

           This variable, if defined, contains the string used by stdio to
           format long doubles (format "F") for output.  The "U" in the name
           is to separate this from sPRIfldbl so that even case-blind systems
           can see the difference.

       "sPRIgldbl"
           From longdblfio.U:

           This variable, if defined, contains the string used by stdio to
           format long doubles (format "g") for output.

       "sPRIGUldbl"
           From longdblfio.U:

           This variable, if defined, contains the string used by stdio to
           format long doubles (format "G") for output.  The "U" in the name
           is to separate this from sPRIgldbl so that even case-blind systems
           can see the difference.

       "sPRIi64"
           From quadfio.U:

           This variable, if defined, contains the string used by stdio to
           format 64-bit decimal numbers (format "i") for output.

       "sPRIo64"
           From quadfio.U:

           This variable, if defined, contains the string used by stdio to
           format 64-bit octal numbers (format "o") for output.

       "sPRIu64"
           From quadfio.U:

           This variable, if defined, contains the string used by stdio to
           format 64-bit unsigned decimal numbers (format "u") for output.

       "sPRIx64"
           From quadfio.U:

           This variable, if defined, contains the string used by stdio to
           format 64-bit hexadecimal numbers (format "x") for output.

       "sPRIXU64"
           From quadfio.U:

           This variable, if defined, contains the string used by stdio to
           format 64-bit hExADECimAl numbers (format "X") for output.  The "U"
           in the name is to separate this from sPRIx64 so that even case-
           blind systems can see the difference.

       "srand48rproto"
           From dsrand48r.U:

           This variable encodes the prototype of srand48r.  It is zero if
           dsrand48r is undef, and one of the "REENTRANTPROTOTABC" macros
           of reentr.h if dsrand48r is defined.

       "srandomrproto"
           From dsrandomr.U:

           This variable encodes the prototype of srandomr.  It is zero if
           dsrandomr is undef, and one of the "REENTRANTPROTOTABC" macros
           of reentr.h if dsrandomr is defined.

       "src"
           From src.U:

           This variable holds the (possibly relative) path of the package
           source.  It is up to the Makefile to use this variable and set
           "VPATH" accordingly to find the sources remotely.  Use $pkgsrc to
           have an absolute path.

       "sSCNfldbl"
           From longdblfio.U:

           This variable, if defined, contains the string used by stdio to
           format long doubles (format "f") for input.

       "ssizetype"
           From ssizetype.U:

           This variable defines ssizetype to be something like ssizet, long
           or int.  It is used by functions that return a count of bytes or an
           error condition.  It must be a signed type.  We will pick a type
           such that sizeof(SSizet) == sizeof(Sizet).

       "stinosign"
           From stinodef.U:

           This variable contains the signedness of struct stat's stino.  1
           for unsigned, -1 for signed.

       "stinosize"
           From stinodef.U:

           This variable contains the size of struct stat's stino in bytes.

       "startperl"
           From startperl.U:

           This variable contains the string to put on the front of a perl
           script to make sure (hopefully) that it runs with perl and not some
           shell. Of course, that leading line must be followed by the
           classical perl idiom: eval 'exec perl -S $0 ${1+$@}' if
           $runningundersomeshell; to guarantee perl startup should the
           shell execute the script. Note that this magic incantation is not
           understood by csh.

       "startsh"
           From startsh.U:

           This variable contains the string to put on the front of a shell
           script to make sure (hopefully) that it runs with sh and not some
           other shell.

       "staticext"
           From Extensions.U:

           This variable holds a list of "XS" extension files we want to link
           statically into the package.  It is used by Makefile.

       "stdchar"
           From stdchar.U:

           This variable conditionally defines "STDCHAR" to be the type of
           char used in stdio.h.  It has the values "unsigned char" or "char".

       "stdiobase"
           From dstdstdio.U:

           This variable defines how, given a "FILE" pointer, fp, to access
           the base field (or equivalent) of stdio.h's "FILE" structure.
           This will be used to define the macro FILEbase(fp).

       "stdiobufsiz"
           From dstdstdio.U:

           This variable defines how, given a "FILE" pointer, fp, to determine
           the number of bytes store in the I/O buffer pointer to by the base
           field (or equivalent) of stdio.h's "FILE" structure.  This will be
           used to define the macro FILEbufsiz(fp).

       "stdiocnt"
           From dstdstdio.U:

           This variable defines how, given a "FILE" pointer, fp, to access
           the cnt field (or equivalent) of stdio.h's "FILE" structure.  This
           will be used to define the macro FILEcnt(fp).

       "stdiofilbuf"
           From dstdstdio.U:

           This variable defines how, given a "FILE" pointer, fp, to tell
           stdio to refill its internal buffers (?).  This will be used to
           define the macro FILEfilbuf(fp).

       "stdioptr"
           From dstdstdio.U:

           This variable defines how, given a "FILE" pointer, fp, to access
           the ptr field (or equivalent) of stdio.h's "FILE" structure.  This
           will be used to define the macro FILEptr(fp).

       "stdiostreamarray"
           From stdiostreams.U:

           This variable tells the name of the array holding the stdio
           streams.  Usual values include iob, iob, and sF.

       "strerrorrproto"
           From dstrerrorr.U:

           This variable encodes the prototype of strerrorr.  It is zero if
           dstrerrorr is undef, and one of the "REENTRANTPROTOTABC"
           macros of reentr.h if dstrerrorr is defined.

       "strings"
           From istring.U:

           This variable holds the full path of the string header that will be
           used. Typically /usr/include/string.h or /usr/include/strings.h.

       "submit"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "subversion"
           From patchlevel.U:

           The subversion level of this package.  The value of subversion
           comes from the patchlevel.h file.  In a version number such as
           5.6.1, this is the 1.  In patchlevel.h, this is referred to as
           "PERLSUBVERSION".  This is unique to perl.

       "sysman"
           From sysman.U:

           This variable holds the place where the manual is located on this
           system. It is not the place where the user wants to put his manual
           pages. Rather it is the place where Configure may look to find
           manual for unix commands (section 1 of the manual usually). See
           mansrc.

   t
       "tail"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "tar"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "targetarch"
           From Cross.U:

           If cross-compiling, this variable contains the target architecture.
           If not, this will be empty.

       "tbl"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "tee"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "test"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the test program.  After Configure runs, the
           value is reset to a plain "test" and is not useful.

       "timeincl"
           From itime.U:

           This variable holds the full path of the included time header(s).

       "timetype"
           From dtime.U:

           This variable holds the type returned by time(). It can be long, or
           timet on "BSD" sites (in which case  should be
           included). Anyway, the type Timet should be used.

       "tmpnamrproto"
           From dtmpnamr.U:

           This variable encodes the prototype of tmpnamr.  It is zero if
           dtmpnamr is undef, and one of the "REENTRANTPROTOTABC" macros
           of reentr.h if dtmpnamr is defined.

       "to"
           From Cross.U:

           This variable contains the command used by Configure to copy to
           from the target host.  Useful and available only during Perl build.
           The string ":" if not cross-compiling.

       "touch"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the touch program.  After Configure runs, the
           value is reset to a plain "touch" and is not useful.

       "tr"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the tr program.  After Configure runs, the
           value is reset to a plain "tr" and is not useful.

       "trnl"
           From trnl.U:

           This variable contains the value to be passed to the tr(1) command
           to transliterate a newline.  Typical values are "\012" and "\n".
           This is needed for "EBCDIC" systems where newline is not
           necessarily "\012".

       "troff"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "ttynamerproto"
           From dttynamer.U:

           This variable encodes the prototype of ttynamer.  It is zero if
           dttynamer is undef, and one of the "REENTRANTPROTOTABC" macros
           of reentr.h if dttynamer is defined.

   u
       "u16size"
           From perlxv.U:

           This variable is the size of an U16 in bytes.

       "u16type"
           From perlxv.U:

           This variable contains the C type used for Perl's U16.

       "u32size"
           From perlxv.U:

           This variable is the size of an U32 in bytes.

       "u32type"
           From perlxv.U:

           This variable contains the C type used for Perl's U32.

       "u64size"
           From perlxv.U:

           This variable is the size of an U64 in bytes.

       "u64type"
           From perlxv.U:

           This variable contains the C type used for Perl's U64.

       "u8size"
           From perlxv.U:

           This variable is the size of an U8 in bytes.

       "u8type"
           From perlxv.U:

           This variable contains the C type used for Perl's U8.

       "uidformat"
           From uidf.U:

           This variable contains the format string used for printing a Uidt.

       "uidsign"
           From uidsign.U:

           This variable contains the signedness of a uidtype.  1 for
           unsigned, -1 for signed.

       "uidsize"
           From uidsize.U:

           This variable contains the size of a uidtype in bytes.

       "uidtype"
           From uidtype.U:

           This variable defines Uidt to be something like uidt, int,
           ushort, or whatever type is used to declare user ids in the kernel.

       "uname"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the uname program.  After Configure runs, the
           value is reset to a plain "uname" and is not useful.

       "uniq"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the uniq program.  After Configure runs, the
           value is reset to a plain "uniq" and is not useful.

       "uquadtype"
           From quadtype.U:

           This variable defines Uquadt to be something like unsigned long,
           unsigned int, unsigned long long, uint64t, or whatever type is
           used for 64-bit integers.

       "use5005threads"
           From usethreads.U:

           This variable conditionally defines the USE5005THREADS symbol, and
           indicates that Perl should be built to use the 5.005-based
           threading implementation. Only valid up to 5.8.x.

       "use64bitall"
           From use64bits.U:

           This variable conditionally defines the USE64BITALL symbol, and
           indicates that 64-bit integer types should be used when available.
           The maximal possible 64-bitness is employed: LP64 or ILP64, meaning
           that you will be able to use more than 2 gigabytes of memory.  This
           mode is even more binary incompatible than USE64BITINT. You may
           not be able to run the resulting executable in a 32-bit "CPU" at
           all or you may need at least to reboot your "OS" to 64-bit mode.

       "use64bitint"
           From use64bits.U:

           This variable conditionally defines the USE64BITINT symbol, and
           indicates that 64-bit integer types should be used when available.
           The minimal possible 64-bitness is employed, just enough to get
           64-bit integers into Perl.  This may mean using for example "long
           longs", while your memory may still be limited to 2 gigabytes.

       "usecrosscompile"
           From Cross.U:

           This variable conditionally defines the "USECROSSCOMPILE" symbol,
           and indicates that Perl has been cross-compiled.

       "usedevel"
           From Devel.U:

           This variable indicates that Perl was configured with development
           features enabled.  This should not be done for production builds.

       "usedl"
           From dlsrc.U:

           This variable indicates if the system supports dynamic loading of
           some sort.  See also dlsrc and dlobj.

       "usedtrace"
           From usedtrace.U:

           This variable indicates whether we are compiling with dtrace
           support. See also dtrace.

       "usefaststdio"
           From usefaststdio.U:

           This variable conditionally defines the "USEFASTSTDIO" symbol,
           and indicates that Perl should be built to use "fast stdio".
           Defaults to define in Perls 5.8 and earlier, to undef later.

       "useithreads"
           From usethreads.U:

           This variable conditionally defines the "USEITHREADS" symbol, and
           indicates that Perl should be built to use the interpreter-based
           threading implementation.

       "usekernprocpathname"
           From usekernprocpathname.U:

           This variable, indicates that we can use sysctl with
           "KERNPROCPATHNAME" to get a full path for the executable, and
           hence convert $^X to an absolute path.

       "uselargefiles"
           From uselfs.U:

           This variable conditionally defines the "USELARGEFILES" symbol,
           and indicates that large file interfaces should be used when
           available.

       "uselongdouble"
           From uselongdbl.U:

           This variable conditionally defines the "USELONGDOUBLE" symbol,
           and indicates that long doubles should be used when available.

       "usemallocwrap"
           From mallocsrc.U:

           This variable contains y if we are wrapping malloc to prevent
           integer overflow during size calculations.

       "usemorebits"
           From usemorebits.U:

           This variable conditionally defines the "USEMOREBITS" symbol, and
           indicates that explicit 64-bit interfaces and long doubles should
           be used when available.

       "usemultiplicity"
           From usemultiplicity.U:

           This variable conditionally defines the "MULTIPLICITY" symbol, and
           indicates that Perl should be built to use multiplicity.

       "usemymalloc"
           From mallocsrc.U:

           This variable contains y if the malloc that comes with this package
           is desired over the system's version of malloc.  People often
           include special versions of malloc for efficiency, but such
           versions are often less portable.  See also mallocsrc and
           mallocobj.  If this is "y", then -lmalloc is removed from $libs.

       "usenm"
           From usenm.U:

           This variable contains "true" or "false" depending whether the nm
           extraction is wanted or not.

       "usensgetexecutablepath"
           From usensgetexecutablepath.U:

           This symbol, if defined, indicates that we can use
           NSGetExecutablePath and realpath to get a full path for the
           executable, and hence convert $^X to an absolute path.

       "useopcode"
           From Extensions.U:

           This variable holds either "true" or "false" to indicate whether
           the Opcode extension should be used.  The sole use for this
           currently is to allow an easy mechanism for users to skip the
           Opcode extension from the Configure command line.

       "useperlio"
           From useperlio.U:

           This variable conditionally defines the "USEPERLIO" symbol, and
           indicates that the PerlIO abstraction should be used throughout.

       "useposix"
           From Extensions.U:

           This variable holds either "true" or "false" to indicate whether
           the "POSIX" extension should be used.  The sole use for this
           currently is to allow an easy mechanism for hints files to indicate
           that "POSIX" will not compile on a particular system.

       "usereentrant"
           From usethreads.U:

           This variable conditionally defines the "USEREENTRANTAPI" symbol,
           which indicates that the thread code may try to use the various r
           versions of library functions.  This is only potentially meaningful
           if usethreads is set and is very experimental, it is not even
           prompted for.

       "userelocatableinc"
           From bin.U:

           This variable is set to true to indicate that perl should relocate
           @"INC" entries at runtime based on the path to the perl binary.
           Any @"INC" paths starting .../ are relocated relative to the
           directory containing the perl binary, and a logical cleanup of the
           path is then made around the join point (removing dir/../ pairs)

       "usesfio"
           From dsfio.U:

           This variable is set to true when the user agrees to use sfio.  It
           is set to false when sfio is not available or when the user
           explicitly requests not to use sfio.  It is here primarily so that
           command-line settings can override the auto-detection of dsfio
           without running into a "WHOA THERE".

       "useshrplib"
           From libperl.U:

           This variable is set to "true" if the user wishes to build a shared
           libperl, and "false" otherwise.

       "usesitecustomize"
           From dsitecustomize.U:

           This variable is set to true when the user requires a mechanism
           that allows the sysadmin to add entries to @"INC" at runtime.  This
           variable being set, makes perl run $sitelib/sitecustomize.pl at
           startup.

       "usesocks"
           From usesocks.U:

           This variable conditionally defines the "USESOCKS" symbol, and
           indicates that Perl should be built to use "SOCKS".

       "usethreads"
           From usethreads.U:

           This variable conditionally defines the "USETHREADS" symbol, and
           indicates that Perl should be built to use threads.

       "usevendorprefix"
           From vendorprefix.U:

           This variable tells whether the vendorprefix and consequently other
           vendor* paths are in use.

       "usevfork"
           From dvfork.U:

           This variable is set to true when the user accepts to use vfork.
           It is set to false when no vfork is available or when the user
           explicitly requests not to use vfork.

       "usrinc"
           From usrinc.U:

           This variable holds the path of the include files, which is usually
           /usr/include. It is mainly used by other Configure units.

       "uuname"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "uvoformat"
           From perlxvf.U:

           This variable contains the format string used for printing a Perl
           "UV" as an unsigned octal integer.

       "uvsize"
           From perlxv.U:

           This variable is the size of a "UV" in bytes.

       "uvtype"
           From perlxv.U:

           This variable contains the C type used for Perl's "UV".

       "uvuformat"
           From perlxvf.U:

           This variable contains the format string used for printing a Perl
           "UV" as an unsigned decimal integer.

       "uvxformat"
           From perlxvf.U:

           This variable contains the format string used for printing a Perl
           "UV" as an unsigned hexadecimal integer in lowercase abcdef.

       "uvXUformat"
           From perlxvf.U:

           This variable contains the format string used for printing a Perl
           "UV" as an unsigned hexadecimal integer in uppercase "ABCDEF".

   v
       "vaproto"
           From vaproto.U:

           This variable conditionally defines "CANVAPROTO" on systems
           supporting prototype declaration of functions with a variable
           number of arguments. See also prototype.

       "vendorarch"
           From vendorarch.U:

           This variable contains the value of the "PERLVENDORARCH" symbol.
           It may have a ~ on the front.  The standard distribution will put
           nothing in this directory.  Vendors who distribute perl may wish to
           place their own architecture-dependent modules and extensions in
           this directory with MakeMaker Makefile.PL "INSTALLDIRS"=vendor or
           equivalent.  See "INSTALL" for details.

       "vendorarchexp"
           From vendorarch.U:

           This variable is the ~name expanded version of vendorarch, so that
           you may use it directly in Makefiles or shell scripts.

       "vendorbin"
           From vendorbin.U:

           This variable contains the eventual value of the "VENDORBIN"
           symbol.  It may have a ~ on the front.  The standard distribution
           will put nothing in this directory.  Vendors who distribute perl
           may wish to place additional binaries in this directory with
           MakeMaker Makefile.PL "INSTALLDIRS"=vendor or equivalent.  See
           "INSTALL" for details.

       "vendorbinexp"
           From vendorbin.U:

           This variable is the ~name expanded version of vendorbin, so that
           you may use it directly in Makefiles or shell scripts.

       "vendorhtml1dir"
           From vendorhtml1dir.U:

           This variable contains the name of the directory for html pages.
           It may have a ~ on the front.  The standard distribution will put
           nothing in this directory.  Vendors who distribute perl may wish to
           place their own html pages in this directory with MakeMaker
           Makefile.PL "INSTALLDIRS"=vendor or equivalent.  See "INSTALL" for
           details.

       "vendorhtml1direxp"
           From vendorhtml1dir.U:

           This variable is the ~name expanded version of vendorhtml1dir, so
           that you may use it directly in Makefiles or shell scripts.

       "vendorhtml3dir"
           From vendorhtml3dir.U:

           This variable contains the name of the directory for html library
           pages.  It may have a ~ on the front.  The standard distribution
           will put nothing in this directory.  Vendors who distribute perl
           may wish to place their own html pages for modules and extensions
           in this directory with MakeMaker Makefile.PL "INSTALLDIRS"=vendor
           or equivalent.  See "INSTALL" for details.

       "vendorhtml3direxp"
           From vendorhtml3dir.U:

           This variable is the ~name expanded version of vendorhtml3dir, so
           that you may use it directly in Makefiles or shell scripts.

       "vendorlib"
           From vendorlib.U:

           This variable contains the eventual value of the "VENDORLIB"
           symbol, which is the name of the private library for this package.
           The standard distribution will put nothing in this directory.
           Vendors who distribute perl may wish to place their own modules in
           this directory with MakeMaker Makefile.PL "INSTALLDIRS"=vendor or
           equivalent.  See "INSTALL" for details.

       "vendorlibstem"
           From vendorlib.U:

           This variable is $vendorlibexp with any trailing version-specific
           component removed.  The elements in incversionlist
           (incversionlist.U) can be tacked onto this variable to generate a
           list of directories to search.

       "vendorlibexp"
           From vendorlib.U:

           This variable is the ~name expanded version of vendorlib, so that
           you may use it directly in Makefiles or shell scripts.

       "vendorman1dir"
           From vendorman1dir.U:

           This variable contains the name of the directory for man1 pages.
           It may have a ~ on the front.  The standard distribution will put
           nothing in this directory.  Vendors who distribute perl may wish to
           place their own man1 pages in this directory with MakeMaker
           Makefile.PL "INSTALLDIRS"=vendor or equivalent.  See "INSTALL" for
           details.

       "vendorman1direxp"
           From vendorman1dir.U:

           This variable is the ~name expanded version of vendorman1dir, so
           that you may use it directly in Makefiles or shell scripts.

       "vendorman3dir"
           From vendorman3dir.U:

           This variable contains the name of the directory for man3 pages.
           It may have a ~ on the front.  The standard distribution will put
           nothing in this directory.  Vendors who distribute perl may wish to
           place their own man3 pages in this directory with MakeMaker
           Makefile.PL "INSTALLDIRS"=vendor or equivalent.  See "INSTALL" for
           details.

       "vendorman3direxp"
           From vendorman3dir.U:

           This variable is the ~name expanded version of vendorman3dir, so
           that you may use it directly in Makefiles or shell scripts.

       "vendorprefix"
           From vendorprefix.U:

           This variable holds the full absolute path of the directory below
           which the vendor will install add-on packages.  See "INSTALL" for
           usage and examples.

       "vendorprefixexp"
           From vendorprefix.U:

           This variable holds the full absolute path of the directory below
           which the vendor will install add-on packages.  Derived from
           vendorprefix.

       "vendorscript"
           From vendorscript.U:

           This variable contains the eventual value of the "VENDORSCRIPT"
           symbol.  It may have a ~ on the front.  The standard distribution
           will put nothing in this directory.  Vendors who distribute perl
           may wish to place additional executable scripts in this directory
           with MakeMaker Makefile.PL "INSTALLDIRS"=vendor or equivalent.  See
           "INSTALL" for details.

       "vendorscriptexp"
           From vendorscript.U:

           This variable is the ~name expanded version of vendorscript, so
           that you may use it directly in Makefiles or shell scripts.

       "version"
           From patchlevel.U:

           The full version number of this package, such as 5.6.1 (or 561).
           This combines revision, patchlevel, and subversion to get the full
           version number, including any possible subversions.  This is
           suitable for use as a directory name, and hence is filesystem
           dependent.

       "versionpatchlevelstring"
           From patchlevel.U:

           This is a string combining version, subversion and perlpatchlevel
           (if perlpatchlevel is non-zero).  It is typically something like
           'version 7 subversion 1'  or 'version 7 subversion 1 patchlevel
           11224' It is computed here to avoid duplication of code in
           myconfig.SH and lib/Config.pm.

       "versiononly"
           From versiononly.U:

           If set, this symbol indicates that only the version-specific
           components of a perl installation should be installed.  This may be
           useful for making a test installation of a new version without
           disturbing the existing installation.  Setting versiononly is
           equivalent to setting installperl's -v option.  In particular, the
           non-versioned scripts and programs such as a2p, c2ph, h2xs, pod2*,
           and perldoc are not installed (see "INSTALL" for a more complete
           list).  Nor are the man pages installed.  Usually, this is undef.

       "vi"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "voidflags"
           From voidflags.U:

           This variable contains the eventual value of the "VOIDFLAGS"
           symbol, which indicates how much support of the void type is given
           by this compiler.  See "VOIDFLAGS" for more info.

   x
       "xlibpth"
           From libpth.U:

           This variable holds extra path (space-separated) used to find
           libraries on this platform, for example "CPU"-specific libraries
           (on multi-"CPU" platforms) may be listed here.

   y
       "yacc"
           From yacc.U:

           This variable holds the name of the compiler compiler we want to
           use in the Makefile. It can be yacc, byacc, or bison -y.

       "yaccflags"
           From yacc.U:

           This variable contains any additional yacc flags desired by the
           user.  It is up to the Makefile to use this.

   z
       "zcat"
           From Loc.U:

           This variable is defined but not used by Configure.  The value is
           the empty string and is not useful.

       "zip"
           From Loc.U:

           This variable is used internally by Configure to determine the full
           pathname (if any) of the zip program.  After Configure runs, the
           value is reset to a plain "zip" and is not useful.

GIT DATA
       Information on the git commit from which the current perl binary was
       compiled can be found in the variable $Config::GitData.  The variable
       is a structured string that looks something like this:

         gitcommitid='ea0c2dbd5f5ac6845ecc7ec6696415bf8e27bd52'
         gitdescribe='GitLive-blead-1076-gea0c2db'
         gitbranch='smartmatch'
         gituncommittedchanges=''
         gitcommitidtitle='Commit id:'
         gitcommitdate='2009-05-09 17:47:31 +0200'

       Its format is not guaranteed not to change over time.

NOTE
       This module contains a good example of how to use tie to implement a
       cache and an example of how to make a tied variable readonly to those
       outside of it.



perl v5.16.3                      2018-10-30                       Config(3pm)