This file contains a description of all the shell variables whose value is determined by the Configure script. Variables intended for use in C programs (e.g. I_UNISTD) are already described in config_h.SH. [`configpm' generates pod documentation for Config.pm from this file--please try to keep the formatting regular.] _a (Unix.U): This variable defines the extension used for ordinary libraries. For unix, it is '.a'. The '.' is included. Other possible values include '.lib'. _exe (Unix.U): This variable defines the extension used for executable files. For unix it is empty. Other possible values include '.exe'. _o (Unix.U): This variable defines the extension used for object files. For unix, it is '.o'. The '.' is included. Other possible values include '.obj'. afs (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 (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 Perl configure and test process. alignbytes (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 (ansi2knr.U): This variable is set if the user needs to run ansi2knr. Currently, this is not supported, so we just abort. aphostname (d_gethname.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. api_revision (patchlevel.U): The three variables, api_revision, api_version, and api_subversion, specify the version of the oldest perl binary compatible with the present perl. In a full version string such as '5.6.1', api_revision 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 site_perl directory was introduced in 5.005, so that is the lowest possible value. The version list appropriate for the current system is determined in inc_version_list.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. api_subversion (patchlevel.U): The three variables, api_revision, api_version, and api_subversion, specify the version of the oldest perl binary compatible with the present perl. In a full version string such as '5.6.1', api_subversion is the '1'. See api_revision for full details. api_version (patchlevel.U): The three variables, api_revision, api_version, and api_subversion, specify the version of the oldest perl binary compatible with the present perl. In a full version string such as '5.6.1', api_version is the '6'. See api_revision for full details. As a special case, 5.5.0 is rendered in the old-style as 5.005. (In the 5.005_0x maintenance series, this was the only versioned directory in $sitelib.) api_versionstring (patchlevel.U): This variable combines api_revision, api_version, and api_subversion in a format such as 5.6.1 (or 5_6_1) suitable for use as a directory name. This is filesystem dependent. ar (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 (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 (archlib.U): This variable is the same as the archlib variable, but is filename expanded at configuration time, for convenient use. archname64 (use64bits.U): This variable is used for the 64-bitness part of $archname. archname (archname.U): This variable is a short name to characterize the current architecture. It is used mainly to construct the default archlib. archobjs (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. awk (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. baserev (baserev.U): The base revision level of this package, from the .package file. bash (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. bin (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. bincompat5005 (bincompat5005.U): This variable contains y if this version of Perl should be binary-compatible with Perl 5.005. binexp (bin.U): This is the same as the bin variable, but is filename expanded at configuration time, for use in your makefiles. bison (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 (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 (byteorder.U): This variable holds the byte order. 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 (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 (d_castneg.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 (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 (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 (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 (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 (ccflags.U): This variable contains any additional C compiler flags desired by the user. It is up to the Makefile to use this. ccflags_uselargefiles (uselfs.U): This variable contains the compiler flags needed by large file builds and added to ccflags by hints files. ccname (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 (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 (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. cf_by (cf_who.U): Login name of the person who ran the Configure script and answered the questions. This is used to tag both config.sh and config_h.SH. cf_email (cf_email.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. cf_time (cf_who.U): Holds the output of the "date" command when the configuration file was produced. This is used to tag both config.sh and config_h.SH. charsize (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 (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. chmod (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. chown (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. clocktype (d_times.U): This variable holds the type returned by times(). It can be long, or clock_t on BSD sites (in which case should be included). comm (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 (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. contains (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 (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 (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. cpp (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. cpp_stuff (cpp_stuff.U): This variable contains an identification of the catenation mechanism used by the C preprocessor. cppccsymbols (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 (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 (cppstdin.U): This variable has the same functionality as cppminus, only it applies to cpprun and not cppstdin. cppminus (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 (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 (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 (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. crosscompile (crosscompile.U): This variable conditionally defines the CROSSCOMPILE symbol which signifies that the build process is be a cross-compilation. This is normally set by hints files or from Configure command line. cryptlib (d_crypt.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 (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. d__fwalk (d__fwalk.U): This variable conditionally defines HAS__FWALK if _fwalk() is available to apply a function to all the file handles. d_access (d_access.U): This variable conditionally defines HAS_ACCESS if the access() system call is available to check for access permissions using real IDs. d_accessx (d_accessx.U): This variable conditionally defines the HAS_ACCESSX symbol, which indicates to the C program that the accessx() routine is available. d_alarm (d_alarm.U): This variable conditionally defines the HAS_ALARM symbol, which indicates to the C program that the alarm() routine is available. d_archlib (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. d_atolf (atolf.U): This variable conditionally defines the HAS_ATOLF symbol, which indicates to the C program that the atolf() routine is available. d_atoll (atoll.U): This variable conditionally defines the HAS_ATOLL symbol, which indicates to the C program that the atoll() routine is available. d_attribut (d_attribut.U): This variable conditionally defines HASATTRIBUTE, which indicates the C compiler can check for function attributes, such as printf formats. d_bcmp (d_bcmp.U): This variable conditionally defines the HAS_BCMP symbol if the bcmp() routine is available to compare strings. d_bcopy (d_bcopy.U): This variable conditionally defines the HAS_BCOPY symbol if the bcopy() routine is available to copy strings. d_bincompat5005 (bincompat5005.U): This variable conditionally defines BINCOMPAT5005 so that embed.h can take special action if this version of Perl should be binary-compatible with Perl 5.005. This is impossible for builds that use features like threads and multiplicity it is always $undef for those versions. d_bsd (Guess.U): This symbol conditionally defines the symbol BSD when running on a BSD system. d_bsdgetpgrp (d_getpgrp.U): This variable conditionally defines USE_BSD_GETPGRP if getpgrp needs one arguments whereas USG one needs none. d_bsdsetpgrp (d_setpgrp.U): This variable conditionally defines USE_BSD_SETPGRP if setpgrp needs two arguments whereas USG one needs none. See also d_setpgid for a POSIX interface. d_bzero (d_bzero.U): This variable conditionally defines the HAS_BZERO symbol if the bzero() routine is available to set memory to 0. d_casti32 (d_casti32.U): This variable conditionally defines CASTI32, which indicates whether the C compiler can cast large floats to 32-bit ints. d_castneg (d_castneg.U): This variable conditionally defines CASTNEG, which indicates wether the C compiler can cast negative float to unsigned. d_charvspr (d_vprintf.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()". d_chown (d_chown.U): This variable conditionally defines the HAS_CHOWN symbol, which indicates to the C program that the chown() routine is available. d_chroot (d_chroot.U): This variable conditionally defines the HAS_CHROOT symbol, which indicates to the C program that the chroot() routine is available. d_chsize (d_chsize.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. d_closedir (d_closedir.U): This variable conditionally defines HAS_CLOSEDIR if closedir() is available. d_cmsghdr_s (d_cmsghdr_s.U): This variable conditionally defines the HAS_STRUCT_CMSGHDR symbol, which indicates that the struct cmsghdr is supported. d_const (d_const.U): This variable conditionally defines the HASCONST symbol, which indicates to the C program that this C compiler knows about the const type. d_crypt (d_crypt.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. d_csh (d_csh.U): This variable conditionally defines the CSH symbol, which indicates to the C program that the C-shell exists. d_cuserid (d_cuserid.U): This variable conditionally defines the HAS_CUSERID symbol, which indicates to the C program that the cuserid() routine is available to get character login names. d_dbl_dig (d_dbl_dig.U): This variable conditionally defines d_dbl_dig if this system's header files provide DBL_DIG, which is the number of significant digits in a double precision number. d_difftime (d_difftime.U): This variable conditionally defines the HAS_DIFFTIME symbol, which indicates to the C program that the difftime() routine is available. d_dirnamlen (i_dirent.U): This variable conditionally defines DIRNAMLEN, which indicates to the C program that the length of directory entry names is provided by a d_namelen field. d_dlerror (d_dlerror.U): This variable conditionally defines the HAS_DLERROR symbol, which indicates to the C program that the dlerror() routine is available. d_dlopen (d_dlopen.U): This variable conditionally defines the HAS_DLOPEN symbol, which indicates to the C program that the dlopen() routine is available. d_dlsymun (d_dlsymun.U): This variable conditionally defines DLSYM_NEEDS_UNDERSCORE, which indicates that we need to prepend an underscore to the symbol name before calling dlsym(). d_dosuid (d_dosuid.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. d_drand48proto (d_drand48proto.U): This variable conditionally defines the HAS_DRAND48_PROTO 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. d_dup2 (d_dup2.U): This variable conditionally defines HAS_DUP2 if dup2() is available to duplicate file descriptors. d_eaccess (d_eaccess.U): This variable conditionally defines the HAS_EACCESS symbol, which indicates to the C program that the eaccess() routine is available. d_endgrent (d_endgrent.U): This variable conditionally defines the HAS_ENDGRENT symbol, which indicates to the C program that the endgrent() routine is available for sequential access of the group database. d_endhent (d_endhent.U): This variable conditionally defines HAS_ENDHOSTENT if endhostent() is available to close whatever was being used for host queries. d_endnent (d_endnent.U): This variable conditionally defines HAS_ENDNETENT if endnetent() is available to close whatever was being used for network queries. d_endpent (d_endpent.U): This variable conditionally defines HAS_ENDPROTOENT if endprotoent() is available to close whatever was being used for protocol queries. d_endpwent (d_endpwent.U): This variable conditionally defines the HAS_ENDPWENT symbol, which indicates to the C program that the endpwent() routine is available for sequential access of the passwd database. d_endsent (d_endsent.U): This variable conditionally defines HAS_ENDSERVENT if endservent() is available to close whatever was being used for service queries. d_eofnblk (nblock_io.U): This variable conditionally defines EOF_NONBLOCK if EOF can be seen when reading from a non-blocking I/O source. d_eunice (Guess.U): This variable conditionally defines the symbols EUNICE and VAX, which alerts the C program that it must deal with ideosyncracies of VMS. d_fchmod (d_fchmod.U): This variable conditionally defines the HAS_FCHMOD symbol, which indicates to the C program that the fchmod() routine is available to change mode of opened files. d_fchown (d_fchown.U): This variable conditionally defines the HAS_FCHOWN symbol, which indicates to the C program that the fchown() routine is available to change ownership of opened files. d_fcntl (d_fcntl.U): This variable conditionally defines the HAS_FCNTL symbol, and indicates whether the fcntl() function exists d_fcntl_can_lock (d_fcntl_can_lock.U): This variable conditionally defines the FCNTL_CAN_LOCK symbol and indicates whether file locking with fcntl() works. d_fd_macros (d_fd_set.U): This variable contains the eventual value of the HAS_FD_MACROS symbol, which indicates if your C compiler knows about the macros which manipulate an fd_set. d_fd_set (d_fd_set.U): This variable contains the eventual value of the HAS_FD_SET symbol, which indicates if your C compiler knows about the fd_set typedef. d_fds_bits (d_fd_set.U): This variable contains the eventual value of the HAS_FDS_BITS symbol, which indicates if your fd_set typedef contains the fds_bits member. If you have an fd_set typedef, but the dweebs who installed it did a half-fast job and neglected to provide the macros to manipulate an fd_set, HAS_FDS_BITS will let us know how to fix the gaffe. d_fgetpos (d_fgetpos.U): This variable conditionally defines HAS_FGETPOS if fgetpos() is available to get the file position indicator. d_flexfnam (d_flexfnam.U): This variable conditionally defines the FLEXFILENAMES symbol, which indicates that the system supports filenames longer than 14 characters. d_flock (d_flock.U): This variable conditionally defines HAS_FLOCK if flock() is available to do file locking. d_fork (d_fork.U): This variable conditionally defines the HAS_FORK symbol, which indicates to the C program that the fork() routine is available. d_fpathconf (d_pathconf.U): This variable conditionally defines the HAS_FPATHCONF 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. d_fpos64_t (d_fpos64_t.U): This symbol will be defined if the C compiler supports fpos64_t. d_frexpl (d_frexpl.U): This variable conditionally defines the HAS_FREXPL symbol, which indicates to the C program that the frexpl() routine is available. d_fs_data_s (d_fs_data_s.U): This variable conditionally defines the HAS_STRUCT_FS_DATA symbol, which indicates that the struct fs_data is supported. d_fseeko (d_fseeko.U): This variable conditionally defines the HAS_FSEEKO symbol, which indicates to the C program that the fseeko() routine is available. d_fsetpos (d_fsetpos.U): This variable conditionally defines HAS_FSETPOS if fsetpos() is available to set the file position indicator. d_fstatfs (d_fstatfs.U): This variable conditionally defines the HAS_FSTATFS symbol, which indicates to the C program that the fstatfs() routine is available. d_fstatvfs (d_statvfs.U): This variable conditionally defines the HAS_FSTATVFS symbol, which indicates to the C program that the fstatvfs() routine is available. d_fsync (d_fsync.U): This variable conditionally defines the HAS_FSYNC symbol, which indicates to the C program that the fsync() routine is available. d_ftello (d_ftello.U): This variable conditionally defines the HAS_FTELLO symbol, which indicates to the C program that the ftello() routine is available. d_ftime (d_ftime.U): This variable conditionally defines the HAS_FTIME symbol, which indicates that the ftime() routine exists. The ftime() routine is basically a sub-second accuracy clock. d_Gconvert (d_gconvert.U): This variable holds what Gconvert is defined as to convert floating point numbers into strings. It could be 'gconvert' or a more complex macro emulating gconvert with gcvt() or sprintf. Possible values are: d_Gconvert='gconvert((x),(n),(t),(b))' d_Gconvert='gcvt((x),(n),(b))' d_Gconvert='sprintf((b),"%.*g",(n),(x))' d_getcwd (d_getcwd.U): This variable conditionally defines the HAS_GETCWD symbol, which indicates to the C program that the getcwd() routine is available to get the current working directory. d_getespwnam (d_getespwnam.U): This variable conditionally defines HAS_GETESPWNAM if getespwnam() is available to retrieve enchanced (shadow) password entries by name. d_getfsstat (d_getfsstat.U): This variable conditionally defines the HAS_GETFSSTAT symbol, which indicates to the C program that the getfsstat() routine is available. d_getgrent (d_getgrent.U): This variable conditionally defines the HAS_GETGRENT symbol, which indicates to the C program that the getgrent() routine is available for sequential access of the group database. d_getgrps (d_getgrps.U): This variable conditionally defines the HAS_GETGROUPS symbol, which indicates to the C program that the getgroups() routine is available to get the list of process groups. d_gethbyaddr (d_gethbyad.U): This variable conditionally defines the HAS_GETHOSTBYADDR symbol, which indicates to the C program that the gethostbyaddr() routine is available to look up hosts by their IP addresses. d_gethbyname (d_gethbynm.U): This variable conditionally defines the HAS_GETHOSTBYNAME symbol, which indicates to the C program that the gethostbyname() routine is available to look up host names in some data base or other. d_gethent (d_gethent.U): This variable conditionally defines HAS_GETHOSTENT if gethostent() is available to look up host names in some data base or another. d_gethname (d_gethname.U): This variable conditionally defines the HAS_GETHOSTNAME symbol, which indicates to the C program that the gethostname() routine may be used to derive the host name. d_gethostprotos (d_gethostprotos.U): This variable conditionally defines the HAS_GETHOST_PROTOS 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. d_getitimer (d_getitimer.U): This variable conditionally defines the HAS_GETITIMER symbol, which indicates to the C program that the getitimer() routine is available. d_getlogin (d_getlogin.U): This variable conditionally defines the HAS_GETLOGIN symbol, which indicates to the C program that the getlogin() routine is available to get the login name. d_getmnt (d_getmnt.U): This variable conditionally defines the HAS_GETMNT symbol, which indicates to the C program that the getmnt() routine is available to retrieve one or more mount info blocks by filename. d_getmntent (d_getmntent.U): This variable conditionally defines the HAS_GETMNTENT symbol, which indicates to the C program that the getmntent() routine is available to iterate through mounted files to get their mount info. d_getnbyaddr (d_getnbyad.U): This variable conditionally defines the HAS_GETNETBYADDR symbol, which indicates to the C program that the getnetbyaddr() routine is available to look up networks by their IP addresses. d_getnbyname (d_getnbynm.U): This variable conditionally defines the HAS_GETNETBYNAME symbol, which indicates to the C program that the getnetbyname() routine is available to look up networks by their names. d_getnent (d_getnent.U): This variable conditionally defines HAS_GETNETENT if getnetent() is available to look up network names in some data base or another. d_getnetprotos (d_getnetprotos.U): This variable conditionally defines the HAS_GETNET_PROTOS 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. d_getpagsz (d_getpagsz.U): This variable conditionally defines HAS_GETPAGESIZE if getpagesize() is available to get the system page size. d_getpbyname (d_getprotby.U): This variable conditionally defines the HAS_GETPROTOBYNAME symbol, which indicates to the C program that the getprotobyname() routine is available to look up protocols by their name. d_getpbynumber (d_getprotby.U): This variable conditionally defines the HAS_GETPROTOBYNUMBER symbol, which indicates to the C program that the getprotobynumber() routine is available to look up protocols by their number. d_getpent (d_getpent.U): This variable conditionally defines HAS_GETPROTOENT if getprotoent() is available to look up protocols in some data base or another. d_getpgid (d_getpgid.U): This variable conditionally defines the HAS_GETPGID symbol, which indicates to the C program that the getpgid(pid) function is available to get the process group id. d_getpgrp2 (d_getpgrp2.U): This variable conditionally defines the HAS_GETPGRP2 symbol, which indicates to the C program that the getpgrp2() (as in DG/UX) routine is available to get the current process group. d_getpgrp (d_getpgrp.U): This variable conditionally defines HAS_GETPGRP if getpgrp() is available to get the current process group. d_getppid (d_getppid.U): This variable conditionally defines the HAS_GETPPID symbol, which indicates to the C program that the getppid() routine is available to get the parent process ID. d_getprior (d_getprior.U): This variable conditionally defines HAS_GETPRIORITY if getpriority() is available to get a process's priority. d_getprotoprotos (d_getprotoprotos.U): This variable conditionally defines the HAS_GETPROTO_PROTOS 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. d_getprpwnam (d_getprpwnam.U): This variable conditionally defines HAS_GETPRPWNAM if getprpwnam() is available to retrieve protected (shadow) password entries by name. d_getpwent (d_getpwent.U): This variable conditionally defines the HAS_GETPWENT symbol, which indicates to the C program that the getpwent() routine is available for sequential access of the passwd database. d_getsbyname (d_getsrvby.U): This variable conditionally defines the HAS_GETSERVBYNAME symbol, which indicates to the C program that the getservbyname() routine is available to look up services by their name. d_getsbyport (d_getsrvby.U): This variable conditionally defines the HAS_GETSERVBYPORT symbol, which indicates to the C program that the getservbyport() routine is available to look up services by their port. d_getsent (d_getsent.U): This variable conditionally defines HAS_GETSERVENT if getservent() is available to look up network services in some data base or another. d_getservprotos (d_getservprotos.U): This variable conditionally defines the HAS_GETSERV_PROTOS 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. d_getspnam (d_getspnam.U): This variable conditionally defines HAS_GETSPNAM if getspnam() is available to retrieve SysV shadow password entries by name. d_gettimeod (d_ftime.U): This variable conditionally defines the HAS_GETTIMEOFDAY symbol, which indicates that the gettimeofday() system call exists (to obtain a sub-second accuracy clock). You should probably include . d_gnulibc (d_gnulibc.U): Defined if we're dealing with the GNU C Library. d_grpasswd (i_grp.U): This variable conditionally defines GRPASSWD, which indicates that struct group in contains gr_passwd. d_hasmntopt (d_hasmntopt.U): This variable conditionally defines the HAS_HASMNTOPT symbol, which indicates to the C program that the hasmntopt() routine is available to query the mount options of file systems. d_htonl (d_htonl.U): This variable conditionally defines HAS_HTONL if htonl() and its friends are available to do network order byte swapping. d_iconv (d_iconv.U): This variable conditionally defines the HAS_ICONV symbol, which indicates to the C program that the iconv() routine is available. d_index (d_strchr.U): This variable conditionally defines HAS_INDEX if index() and rindex() are available for string searching. d_inetaton (d_inetaton.U): This variable conditionally defines the HAS_INET_ATON symbol, which indicates to the C program that the inet_aton() function is available to parse IP address "dotted-quad" strings. d_int64_t (d_int64_t.U): This symbol will be defined if the C compiler supports int64_t. d_isascii (d_isascii.U): This variable conditionally defines the HAS_ISASCII constant, which indicates to the C program that isascii() is available. d_isnan (d_isnan.U): This variable conditionally defines the HAS_ISNAN symbol, which indicates to the C program that the isnan() routine is available. d_isnanl (d_isnanl.U): This variable conditionally defines the HAS_ISNANL symbol, which indicates to the C program that the isnanl() routine is available. d_killpg (d_killpg.U): This variable conditionally defines the HAS_KILLPG symbol, which indicates to the C program that the killpg() routine is available to kill process groups. d_lchown (d_lchown.U): This variable conditionally defines the HAS_LCHOWN symbol, which indicates to the C program that the lchown() routine is available to operate on a symbolic link (instead of following the link). d_ldbl_dig (d_ldbl_dig.U): This variable conditionally defines d_ldbl_dig if this system's header files provide LDBL_DIG, which is the number of significant digits in a long double precision number. d_link (d_link.U): This variable conditionally defines HAS_LINK if link() is available to create hard links. d_locconv (d_locconv.U): This variable conditionally defines HAS_LOCALECONV if localeconv() is available for numeric and monetary formatting conventions. d_lockf (d_lockf.U): This variable conditionally defines HAS_LOCKF if lockf() is available to do file locking. d_longdbl (d_longdbl.U): This variable conditionally defines HAS_LONG_DOUBLE if the long double type is supported. d_longlong (d_longlong.U): This variable conditionally defines HAS_LONG_LONG if the long long type is supported. d_lseekproto (d_lseekproto.U): This variable conditionally defines the HAS_LSEEK_PROTO 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. d_lstat (d_lstat.U): This variable conditionally defines HAS_LSTAT if lstat() is available to do file stats on symbolic links. d_madvise (d_madvise.U): This variable conditionally defines HAS_MADVISE if madvise() is available to map a file into memory. d_mblen (d_mblen.U): This variable conditionally defines the HAS_MBLEN symbol, which indicates to the C program that the mblen() routine is available to find the number of bytes in a multibye character. d_mbstowcs (d_mbstowcs.U): This variable conditionally defines the HAS_MBSTOWCS symbol, which indicates to the C program that the mbstowcs() routine is available to convert a multibyte string into a wide character string. d_mbtowc (d_mbtowc.U): This variable conditionally defines the HAS_MBTOWC symbol, which indicates to the C program that the mbtowc() routine is available to convert multibyte to a wide character. d_memchr (d_memchr.U): This variable conditionally defines the HAS_MEMCHR symbol, which indicates to the C program that the memchr() routine is available to locate characters within a C string. d_memcmp (d_memcmp.U): This variable conditionally defines the HAS_MEMCMP symbol, which indicates to the C program that the memcmp() routine is available to compare blocks of memory. d_memcpy (d_memcpy.U): This variable conditionally defines the HAS_MEMCPY symbol, which indicates to the C program that the memcpy() routine is available to copy blocks of memory. d_memmove (d_memmove.U): This variable conditionally defines the HAS_MEMMOVE symbol, which indicates to the C program that the memmove() routine is available to copy potentatially overlapping blocks of memory. d_memset (d_memset.U): This variable conditionally defines the HAS_MEMSET symbol, which indicates to the C program that the memset() routine is available to set blocks of memory. d_mkdir (d_mkdir.U): This variable conditionally defines the HAS_MKDIR symbol, which indicates to the C program that the mkdir() routine is available to create directories.. d_mkdtemp (d_mkdtemp.U): This variable conditionally defines the HAS_MKDTEMP symbol, which indicates to the C program that the mkdtemp() routine is available to exclusively create a uniquely named temporary directory. d_mkfifo (d_mkfifo.U): This variable conditionally defines the HAS_MKFIFO symbol, which indicates to the C program that the mkfifo() routine is available. d_mkstemp (d_mkstemp.U): This variable conditionally defines the HAS_MKSTEMP symbol, which indicates to the C program that the mkstemp() routine is available to exclusively create and open a uniquely named temporary file. d_mkstemps (d_mkstemps.U): This variable conditionally defines the HAS_MKSTEMPS 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. d_mktime (d_mktime.U): This variable conditionally defines the HAS_MKTIME symbol, which indicates to the C program that the mktime() routine is available. d_mmap (d_mmap.U): This variable conditionally defines HAS_MMAP if mmap() is available to map a file into memory. d_modfl (d_modfl.U): This variable conditionally defines the HAS_MODFL symbol, which indicates to the C program that the modfl() routine is available. d_mprotect (d_mprotect.U): This variable conditionally defines HAS_MPROTECT if mprotect() is available to modify the access protection of a memory mapped file. d_msg (d_msg.U): This variable conditionally defines the HAS_MSG symbol, which indicates that the entire msg*(2) library is present. d_msg_ctrunc (d_socket.U): This variable conditionally defines the HAS_MSG_CTRUNC symbol, which indicates that the MSG_CTRUNC is available. #ifdef is not enough because it may be an enum, glibc has been known to do this. d_msg_dontroute (d_socket.U): This variable conditionally defines the HAS_MSG_DONTROUTE symbol, which indicates that the MSG_DONTROUTE is available. #ifdef is not enough because it may be an enum, glibc has been known to do this. d_msg_oob (d_socket.U): This variable conditionally defines the HAS_MSG_OOB symbol, which indicates that the MSG_OOB is available. #ifdef is not enough because it may be an enum, glibc has been known to do this. d_msg_peek (d_socket.U): This variable conditionally defines the HAS_MSG_PEEK symbol, which indicates that the MSG_PEEK is available. #ifdef is not enough because it may be an enum, glibc has been known to do this. d_msg_proxy (d_socket.U): This variable conditionally defines the HAS_MSG_PROXY symbol, which indicates that the MSG_PROXY is available. #ifdef is not enough because it may be an enum, glibc has been known to do this. d_msgctl (d_msgctl.U): This variable conditionally defines the HAS_MSGCTL symbol, which indicates to the C program that the msgctl() routine is available. d_msgget (d_msgget.U): This variable conditionally defines the HAS_MSGGET symbol, which indicates to the C program that the msgget() routine is available. d_msghdr_s (d_msghdr_s.U): This variable conditionally defines the HAS_STRUCT_MSGHDR symbol, which indicates that the struct msghdr is supported. d_msgrcv (d_msgrcv.U): This variable conditionally defines the HAS_MSGRCV symbol, which indicates to the C program that the msgrcv() routine is available. d_msgsnd (d_msgsnd.U): This variable conditionally defines the HAS_MSGSND symbol, which indicates to the C program that the msgsnd() routine is available. d_msync (d_msync.U): This variable conditionally defines HAS_MSYNC if msync() is available to synchronize a mapped file. d_munmap (d_munmap.U): This variable conditionally defines HAS_MUNMAP if munmap() is available to unmap a region mapped by mmap(). d_mymalloc (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. d_nice (d_nice.U): This variable conditionally defines the HAS_NICE symbol, which indicates to the C program that the nice() routine is available. d_nv_preserves_uv (perlxv.U): This variable indicates whether a variable of type nvtype can preserve all the bits a variable of type uvtype. d_nv_preserves_uv_bits (perlxv.U): This variable indicates how many of bits type uvtype a variable nvtype can preserve. d_off64_t (d_off64_t.U): This symbol will be defined if the C compiler supports off64_t. d_old_pthread_create_joinable (d_pthrattrj.U): This variable conditionally defines pthread_create_joinable. undef if pthread.h defines PTHREAD_CREATE_JOINABLE. d_oldpthreads (usethreads.U): This variable conditionally defines the OLD_PTHREADS_API 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. d_oldsock (d_socket.U): This variable conditionally defines the OLDSOCKET symbol, which indicates that the BSD socket interface is based on 4.1c and not 4.2. d_open3 (d_open3.U): This variable conditionally defines the HAS_OPEN3 manifest constant, which indicates to the C program that the 3 argument version of the open(2) function is available. d_pathconf (d_pathconf.U): This variable conditionally defines the HAS_PATHCONF 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. d_pause (d_pause.U): This variable conditionally defines the HAS_PAUSE symbol, which indicates to the C program that the pause() routine is available to suspend a process until a signal is received. d_perl_otherlibdirs (otherlibdirs.U): This variable conditionally defines PERL_OTHERLIBDIRS, which contains a colon-separated set of paths for the perl binary to include in @INC. See also otherlibdirs. d_phostname (d_gethname.U): This variable conditionally defines the HAS_PHOSTNAME symbol, which contains the shell command which, when fed to popen(), may be used to derive the host name. d_pipe (d_pipe.U): This variable conditionally defines the HAS_PIPE symbol, which indicates to the C program that the pipe() routine is available to create an inter-process channel. d_poll (d_poll.U): This variable conditionally defines the HAS_POLL symbol, which indicates to the C program that the poll() routine is available to poll active file descriptors. d_portable (d_portable.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. d_PRId64 (quadfio.U): This variable conditionally defines the PERL_PRId64 symbol, which indiciates that stdio has a symbol to print 64-bit decimal numbers. d_PRIeldbl (longdblfio.U): This variable conditionally defines the PERL_PRIfldbl symbol, which indiciates that stdio has a symbol to print long doubles. d_PRIEUldbl (longdblfio.U): This variable conditionally defines the PERL_PRIfldbl symbol, which indiciates that stdio has a symbol to print long doubles. The 'U' in the name is to separate this from d_PRIeldbl so that even case-blind systems can see the difference. d_PRIfldbl (longdblfio.U): This variable conditionally defines the PERL_PRIfldbl symbol, which indiciates that stdio has a symbol to print long doubles. d_PRIFUldbl (longdblfio.U): This variable conditionally defines the PERL_PRIfldbl symbol, which indiciates that stdio has a symbol to print long doubles. The 'U' in the name is to separate this from d_PRIfldbl so that even case-blind systems can see the difference. d_PRIgldbl (longdblfio.U): This variable conditionally defines the PERL_PRIfldbl symbol, which indiciates that stdio has a symbol to print long doubles. d_PRIGUldbl (longdblfio.U): This variable conditionally defines the PERL_PRIfldbl symbol, which indiciates that stdio has a symbol to print long doubles. The 'U' in the name is to separate this from d_PRIgldbl so that even case-blind systems can see the difference. d_PRIi64 (quadfio.U): This variable conditionally defines the PERL_PRIi64 symbol, which indiciates that stdio has a symbol to print 64-bit decimal numbers. d_PRIo64 (quadfio.U): This variable conditionally defines the PERL_PRIo64 symbol, which indiciates that stdio has a symbol to print 64-bit octal numbers. d_PRIu64 (quadfio.U): This variable conditionally defines the PERL_PRIu64 symbol, which indiciates that stdio has a symbol to print 64-bit unsigned decimal numbers. d_PRIx64 (quadfio.U): This variable conditionally defines the PERL_PRIx64 symbol, which indiciates that stdio has a symbol to print 64-bit hexadecimal numbers. d_PRIXU64 (quadfio.U): This variable conditionally defines the PERL_PRIXU64 symbol, which indiciates that stdio has a symbol to print 64-bit hExADECimAl numbers. The 'U' in the name is to separate this from d_PRIx64 so that even case-blind systems can see the difference. d_pthread_yield (d_pthread_y.U): This variable conditionally defines the HAS_PTHREAD_YIELD symbol if the pthread_yield routine is available to yield the execution of the current thread. d_pwage (i_pwd.U): This variable conditionally defines PWAGE, which indicates that struct passwd contains pw_age. d_pwchange (i_pwd.U): This variable conditionally defines PWCHANGE, which indicates that struct passwd contains pw_change. d_pwclass (i_pwd.U): This variable conditionally defines PWCLASS, which indicates that struct passwd contains pw_class. d_pwcomment (i_pwd.U): This variable conditionally defines PWCOMMENT, which indicates that struct passwd contains pw_comment. d_pwexpire (i_pwd.U): This variable conditionally defines PWEXPIRE, which indicates that struct passwd contains pw_expire. d_pwgecos (i_pwd.U): This variable conditionally defines PWGECOS, which indicates that struct passwd contains pw_gecos. d_pwpasswd (i_pwd.U): This variable conditionally defines PWPASSWD, which indicates that struct passwd contains pw_passwd. d_pwquota (i_pwd.U): This variable conditionally defines PWQUOTA, which indicates that struct passwd contains pw_quota. d_qgcvt (d_qgcvt.U): This variable conditionally defines the HAS_QGCVT symbol, which indicates to the C program that the qgcvt() routine is available. d_quad (quadtype.U): This variable, if defined, tells that there's a 64-bit integer type, quadtype. d_readdir (d_readdir.U): This variable conditionally defines HAS_READDIR if readdir() is available to read directory entries. d_readlink (d_readlink.U): This variable conditionally defines the HAS_READLINK symbol, which indicates to the C program that the readlink() routine is available to read the value of a symbolic link. d_readv (d_readv.U): This variable conditionally defines the HAS_READV symbol, which indicates to the C program that the readv() routine is available. d_recvmsg (d_recvmsg.U): This variable conditionally defines the HAS_RECVMSG symbol, which indicates to the C program that the recvmsg() routine is available. d_rename (d_rename.U): This variable conditionally defines the HAS_RENAME symbol, which indicates to the C program that the rename() routine is available to rename files. d_rewinddir (d_readdir.U): This variable conditionally defines HAS_REWINDDIR if rewinddir() is available. d_rmdir (d_rmdir.U): This variable conditionally defines HAS_RMDIR if rmdir() is available to remove directories. d_safebcpy (d_safebcpy.U): This variable conditionally defines the HAS_SAFE_BCOPY symbol if the bcopy() routine can do overlapping copies. d_safemcpy (d_safemcpy.U): This variable conditionally defines the HAS_SAFE_MEMCPY symbol if the memcpy() routine can do overlapping copies. d_sanemcmp (d_sanemcmp.U): This variable conditionally defines the HAS_SANE_MEMCMP symbol if the memcpy() routine is available and can be used to compare relative magnitudes of chars with their high bits set. d_sbrkproto (d_sbrkproto.U): This variable conditionally defines the HAS_SBRK_PROTO 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. d_sched_yield (d_pthread_y.U): This variable conditionally defines the HAS_SCHED_YIELD symbol if the sched_yield routine is available to yield the execution of the current thread. d_scm_rights (d_socket.U): This variable conditionally defines the HAS_SCM_RIGHTS symbol, which indicates that the SCM_RIGHTS is available. #ifdef is not enough because it may be an enum, glibc has been known to do this. d_SCNfldbl (longdblfio.U): This variable conditionally defines the PERL_PRIfldbl symbol, which indiciates that stdio has a symbol to scan long doubles. d_seekdir (d_readdir.U): This variable conditionally defines HAS_SEEKDIR if seekdir() is available. d_select (d_select.U): This variable conditionally defines HAS_SELECT if select() is available to select active file descriptors. A inclusion may be necessary for the timeout field. d_sem (d_sem.U): This variable conditionally defines the HAS_SEM symbol, which indicates that the entire sem*(2) library is present. d_semctl (d_semctl.U): This variable conditionally defines the HAS_SEMCTL symbol, which indicates to the C program that the semctl() routine is available. d_semctl_semid_ds (d_union_semun.U): This variable conditionally defines USE_SEMCTL_SEMID_DS, which indicates that struct semid_ds * is to be used for semctl IPC_STAT. d_semctl_semun (d_union_semun.U): This variable conditionally defines USE_SEMCTL_SEMUN, which indicates that union semun is to be used for semctl IPC_STAT. d_semget (d_semget.U): This variable conditionally defines the HAS_SEMGET symbol, which indicates to the C program that the semget() routine is available. d_semop (d_semop.U): This variable conditionally defines the HAS_SEMOP symbol, which indicates to the C program that the semop() routine is available. d_sendmsg (d_sendmsg.U): This variable conditionally defines the HAS_SENDMSG symbol, which indicates to the C program that the sendmsg() routine is available. d_setegid (d_setegid.U): This variable conditionally defines the HAS_SETEGID symbol, which indicates to the C program that the setegid() routine is available to change the effective gid of the current program. d_seteuid (d_seteuid.U): This variable conditionally defines the HAS_SETEUID symbol, which indicates to the C program that the seteuid() routine is available to change the effective uid of the current program. d_setgrent (d_setgrent.U): This variable conditionally defines the HAS_SETGRENT symbol, which indicates to the C program that the setgrent() routine is available for initializing sequential access to the group database. d_setgrps (d_setgrps.U): This variable conditionally defines the HAS_SETGROUPS symbol, which indicates to the C program that the setgroups() routine is available to set the list of process groups. d_sethent (d_sethent.U): This variable conditionally defines HAS_SETHOSTENT if sethostent() is available. d_setitimer (d_setitimer.U): This variable conditionally defines the HAS_SETITIMER symbol, which indicates to the C program that the setitimer() routine is available. d_setlinebuf (d_setlnbuf.U): This variable conditionally defines the HAS_SETLINEBUF 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. d_setlocale (d_setlocale.U): This variable conditionally defines HAS_SETLOCALE if setlocale() is available to handle locale-specific ctype implementations. d_setnent (d_setnent.U): This variable conditionally defines HAS_SETNETENT if setnetent() is available. d_setpent (d_setpent.U): This variable conditionally defines HAS_SETPROTOENT if setprotoent() is available. d_setpgid (d_setpgid.U): This variable conditionally defines the HAS_SETPGID symbol if the setpgid(pid, gpid) function is available to set process group ID. d_setpgrp2 (d_setpgrp2.U): This variable conditionally defines the HAS_SETPGRP2 symbol, which indicates to the C program that the setpgrp2() (as in DG/UX) routine is available to set the current process group. d_setpgrp (d_setpgrp.U): This variable conditionally defines HAS_SETPGRP if setpgrp() is available to set the current process group. d_setprior (d_setprior.U): This variable conditionally defines HAS_SETPRIORITY if setpriority() is available to set a process's priority. d_setproctitle (d_setproctitle.U): This variable conditionally defines the HAS_SETPROCTITLE symbol, which indicates to the C program that the setproctitle() routine is available. d_setpwent (d_setpwent.U): This variable conditionally defines the HAS_SETPWENT symbol, which indicates to the C program that the setpwent() routine is available for initializing sequential access to the passwd database. d_setregid (d_setregid.U): This variable conditionally defines HAS_SETREGID if setregid() is available to change the real and effective gid of the current process. d_setresgid (d_setregid.U): This variable conditionally defines HAS_SETRESGID if setresgid() is available to change the real, effective and saved gid of the current process. d_setresuid (d_setreuid.U): This variable conditionally defines HAS_SETREUID if setresuid() is available to change the real, effective and saved uid of the current process. d_setreuid (d_setreuid.U): This variable conditionally defines HAS_SETREUID if setreuid() is available to change the real and effective uid of the current process. d_setrgid (d_setrgid.U): This variable conditionally defines the HAS_SETRGID symbol, which indicates to the C program that the setrgid() routine is available to change the real gid of the current program. d_setruid (d_setruid.U): This variable conditionally defines the HAS_SETRUID symbol, which indicates to the C program that the setruid() routine is available to change the real uid of the current program. d_setsent (d_setsent.U): This variable conditionally defines HAS_SETSERVENT if setservent() is available. d_setsid (d_setsid.U): This variable conditionally defines HAS_SETSID if setsid() is available to set the process group ID. d_setvbuf (d_setvbuf.U): This variable conditionally defines the HAS_SETVBUF symbol, which indicates to the C program that the setvbuf() routine is available to change buffering on an open stdio stream. d_sfio (d_sfio.U): This variable conditionally defines the USE_SFIO symbol, and indicates whether sfio is available (and should be used). d_shm (d_shm.U): This variable conditionally defines the HAS_SHM symbol, which indicates that the entire shm*(2) library is present. d_shmat (d_shmat.U): This variable conditionally defines the HAS_SHMAT symbol, which indicates to the C program that the shmat() routine is available. d_shmatprototype (d_shmat.U): This variable conditionally defines the HAS_SHMAT_PROTOTYPE symbol, which indicates that sys/shm.h has a prototype for shmat. d_shmctl (d_shmctl.U): This variable conditionally defines the HAS_SHMCTL symbol, which indicates to the C program that the shmctl() routine is available. d_shmdt (d_shmdt.U): This variable conditionally defines the HAS_SHMDT symbol, which indicates to the C program that the shmdt() routine is available. d_shmget (d_shmget.U): This variable conditionally defines the HAS_SHMGET symbol, which indicates to the C program that the shmget() routine is available. d_sigaction (d_sigaction.U): This variable conditionally defines the HAS_SIGACTION symbol, which indicates that the Vr4 sigaction() routine is available. d_sigprocmask (d_sigprocmask.U): This variable conditionally defines HAS_SIGPROCMASK if sigprocmask() is available to examine or change the signal mask of the calling process. d_sigsetjmp (d_sigsetjmp.U): This variable conditionally defines the HAS_SIGSETJMP symbol, which indicates that the sigsetjmp() routine is available to call setjmp() and optionally save the process's signal mask. d_sockatmark (d_sockatmark.U): This variable conditionally defines the HAS_SOCKATMARK symbol, which indicates to the C program that the sockatmark() routine is available. d_socket (d_socket.U): This variable conditionally defines HAS_SOCKET, which indicates that the BSD socket interface is supported. d_socklen_t (d_socklen_t.U): This symbol will be defined if the C compiler supports socklen_t. d_sockpair (d_socket.U): This variable conditionally defines the HAS_SOCKETPAIR symbol, which indicates that the BSD socketpair() is supported. d_socks5_init (d_socks5_init.U): This variable conditionally defines the HAS_SOCKS5_INIT symbol, which indicates to the C program that the socks5_init() routine is available. d_sqrtl (d_sqrtl.U): This variable conditionally defines the HAS_SQRTL symbol, which indicates to the C program that the sqrtl() routine is available. d_statblks (d_statblks.U): This variable conditionally defines USE_STAT_BLOCKS if this system has a stat structure declaring st_blksize and st_blocks. d_statfs_f_flags (d_statfs_f_flags.U): This variable conditionally defines the HAS_STRUCT_STATFS_F_FLAGS symbol, which indicates to struct statfs from has f_flags member. This kind of struct statfs is coming from sys/mount.h (BSD), not from sys/statfs.h (SYSV). d_statfs_s (d_statfs_s.U): This variable conditionally defines the HAS_STRUCT_STATFS symbol, which indicates that the struct statfs is supported. d_statvfs (d_statvfs.U): This variable conditionally defines the HAS_STATVFS symbol, which indicates to the C program that the statvfs() routine is available. d_stdio_cnt_lval (d_stdstdio.U): This variable conditionally defines STDIO_CNT_LVALUE if the FILE_cnt macro can be used as an lvalue. d_stdio_ptr_lval (d_stdstdio.U): This variable conditionally defines STDIO_PTR_LVALUE if the FILE_ptr macro can be used as an lvalue. d_stdio_ptr_lval_nochange_cnt (d_stdstdio.U): This symbol is defined if using the FILE_ptr macro as an lvalue to increase the pointer by n leaves File_cnt(fp) unchanged. d_stdio_ptr_lval_sets_cnt (d_stdstdio.U): This symbol is defined if using the FILE_ptr macro as an lvalue to increase the pointer by n has the side effect of decreasing the value of File_cnt(fp) by n. d_stdio_stream_array (stdio_streams.U): This variable tells whether there is an array holding the stdio streams. d_stdiobase (d_stdstdio.U): This variable conditionally defines USE_STDIO_BASE if this system has a FILE structure declaring a usable _base field (or equivalent) in stdio.h. d_stdstdio (d_stdstdio.U): This variable conditionally defines USE_STDIO_PTR if this system has a FILE structure declaring usable _ptr and _cnt fields (or equivalent) in stdio.h. d_strchr (d_strchr.U): This variable conditionally defines HAS_STRCHR if strchr() and strrchr() are available for string searching. d_strcoll (d_strcoll.U): This variable conditionally defines HAS_STRCOLL if strcoll() is available to compare strings using collating information. d_strctcpy (d_strctcpy.U): This variable conditionally defines the USE_STRUCT_COPY symbol, which indicates to the C program that this C compiler knows how to copy structures. d_strerrm (d_strerror.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 sys_errlist[], or the "unknown" string when both strerror and sys_errlist are missing. d_strerror (d_strerror.U): This variable conditionally defines HAS_STRERROR if strerror() is available to translate error numbers to strings. d_strftime (d_strftime.U): This variable conditionally defines the HAS_STRFTIME symbol, which indicates to the C program that the strftime() routine is available. d_strtod (d_strtod.U): This variable conditionally defines the HAS_STRTOD symbol, which indicates to the C program that the strtod() routine is available to provide better numeric string conversion than atof(). d_strtol (d_strtol.U): This variable conditionally defines the HAS_STRTOL symbol, which indicates to the C program that the strtol() routine is available to provide better numeric string conversion than atoi() and friends. d_strtold (d_strtold.U): This variable conditionally defines the HAS_STRTOLD symbol, which indicates to the C program that the strtold() routine is available. d_strtoll (d_strtoll.U): This variable conditionally defines the HAS_STRTOLL symbol, which indicates to the C program that the strtoll() routine is available. d_strtoq (d_strtoq.U): This variable conditionally defines the HAS_STRTOQ symbol, which indicates to the C program that the strtoq() routine is available. d_strtoul (d_strtoul.U): This variable conditionally defines the HAS_STRTOUL symbol, which indicates to the C program that the strtoul() routine is available to provide conversion of strings to unsigned long. d_strtoull (d_strtoull.U): This variable conditionally defines the HAS_STRTOULL symbol, which indicates to the C program that the strtoull() routine is available. d_strtouq (d_strtouq.U): This variable conditionally defines the HAS_STRTOUQ symbol, which indicates to the C program that the strtouq() routine is available. d_strxfrm (d_strxfrm.U): This variable conditionally defines HAS_STRXFRM if strxfrm() is available to transform strings. d_suidsafe (d_dosuid.U): This variable conditionally defines SETUID_SCRIPTS_ARE_SECURE_NOW if setuid scripts can be secure. This test looks in /dev/fd/. d_symlink (d_symlink.U): This variable conditionally defines the HAS_SYMLINK symbol, which indicates to the C program that the symlink() routine is available to create symbolic links. d_syscall (d_syscall.U): This variable conditionally defines HAS_SYSCALL if syscall() is available call arbitrary system calls. d_sysconf (d_sysconf.U): This variable conditionally defines the HAS_SYSCONF symbol, which indicates to the C program that the sysconf() routine is available to determine system related limits and options. d_sysernlst (d_strerror.U): This variable conditionally defines HAS_SYS_ERRNOLIST if sys_errnolist[] is available to translate error numbers to the symbolic name. d_syserrlst (d_strerror.U): This variable conditionally defines HAS_SYS_ERRLIST if sys_errlist[] is available to translate error numbers to strings. d_system (d_system.U): This variable conditionally defines HAS_SYSTEM if system() is available to issue a shell command. d_tcgetpgrp (d_tcgtpgrp.U): This variable conditionally defines the HAS_TCGETPGRP symbol, which indicates to the C program that the tcgetpgrp() routine is available. to get foreground process group ID. d_tcsetpgrp (d_tcstpgrp.U): This variable conditionally defines the HAS_TCSETPGRP symbol, which indicates to the C program that the tcsetpgrp() routine is available to set foreground process group ID. d_telldir (d_readdir.U): This variable conditionally defines HAS_TELLDIR if telldir() is available. d_telldirproto (d_telldirproto.U): This variable conditionally defines the HAS_TELLDIR_PROTO 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. d_time (d_time.U): This variable conditionally defines the HAS_TIME symbol, which indicates that the time() routine exists. The time() routine is normaly provided on UNIX systems. d_times (d_times.U): This variable conditionally defines the HAS_TIMES symbol, which indicates that the times() routine exists. The times() routine is normaly provided on UNIX systems. You may have to include . d_truncate (d_truncate.U): This variable conditionally defines HAS_TRUNCATE if truncate() is available to truncate files. d_tzname (d_tzname.U): This variable conditionally defines HAS_TZNAME if tzname[] is available to access timezone names. d_u32align (d_u32align.U): This variable tells whether you must access character data through U32-aligned pointers. d_ualarm (d_ualarm.U): This variable conditionally defines the HAS_UALARM symbol, which indicates to the C program that the ualarm() routine is available. d_umask (d_umask.U): This variable conditionally defines the HAS_UMASK symbol, which indicates to the C program that the umask() routine is available. to set and get the value of the file creation mask. d_uname (d_gethname.U): This variable conditionally defines the HAS_UNAME symbol, which indicates to the C program that the uname() routine may be used to derive the host name. d_union_semun (d_union_semun.U): This variable conditionally defines HAS_UNION_SEMUN if the union semun is defined by including . d_usleep (d_usleep.U): This variable conditionally defines HAS_USLEEP if usleep() is available to do high granularity sleeps. d_ustat (d_ustat.U): This variable conditionally defines HAS_USTAT if ustat() is available to query file system statistics by dev_t. d_vendorarch (vendorarch.U): This variable conditionally defined PERL_VENDORARCH. d_vendorbin (vendorbin.U): This variable conditionally defines PERL_VENDORBIN. d_vendorlib (vendorlib.U): This variable conditionally defines PERL_VENDORLIB. d_vfork (d_vfork.U): This variable conditionally defines the HAS_VFORK symbol, which indicates the vfork() routine is available. d_void_closedir (d_closedir.U): This variable conditionally defines VOID_CLOSEDIR if closedir() does not return a value. d_voidsig (d_voidsig.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(...))()". d_voidtty (i_sysioctl.U): This variable conditionally defines USE_IOCNOTTY 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 decriptors and do a setpgrp(). d_volatile (d_volatile.U): This variable conditionally defines the HASVOLATILE symbol, which indicates to the C program that this C compiler knows about the volatile declaration. d_vprintf (d_vprintf.U): This variable conditionally defines the HAS_VPRINTF symbol, which indicates to the C program that the vprintf() routine is available to printf with a pointer to an argument list. d_wait4 (d_wait4.U): This variable conditionally defines the HAS_WAIT4 symbol, which indicates the wait4() routine is available. d_waitpid (d_waitpid.U): This variable conditionally defines HAS_WAITPID if waitpid() is available to wait for child process. d_wcstombs (d_wcstombs.U): This variable conditionally defines the HAS_WCSTOMBS symbol, which indicates to the C program that the wcstombs() routine is available to convert wide character strings to multibyte strings. d_wctomb (d_wctomb.U): This variable conditionally defines the HAS_WCTOMB symbol, which indicates to the C program that the wctomb() routine is available to convert a wide character to a multibyte. d_writev (d_writev.U): This variable conditionally defines the HAS_WRITEV symbol, which indicates to the C program that the writev() routine is available. d_xenix (Guess.U): This variable conditionally defines the symbol XENIX, which alerts the C program that it runs under Xenix. date (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. db_hashtype (i_db.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 u_int32_t. db_prefixtype (i_db.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 size_t. defvoidused (voidflags.U): This variable contains the default value of the VOIDUSED symbol (15). direntrytype (i_dirent.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 (dlext.U): This variable contains the extension that is to be used for the dynamically loaded modules that perl generaties. dlsrc (dlsrc.U): This variable contains the name of the dynamic loading file that will be used with the package. doublesize (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 (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. dynamic_ext (Extensions.U): This variable holds a list of XS extension files we want to link dynamically into the package. It is used by Makefile. eagain (nblock_io.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 (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 (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 (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 (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. eunicefix (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. exe_ext (Unix.U): This is an old synonym for _exe. expr (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 (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 extesion is available. fflushall (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 (fflushall.U): This symbol, if defined, tells that fflush(NULL) does flush all pending stdio output. find (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. firstmakefile (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 (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. fpossize (fpossize.U): This variable contains the size of a fpostype in bytes. fpostype (fpostype.U): This variable defines Fpos_t to be something like fpos_t, long, uint, or whatever type is used to declare file positions in libc. freetype (mallocsrc.U): This variable contains the return type of free(). It is usually void, but occasionally int. full_ar (Loc_ar.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. full_csh (d_csh.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.' full_sed (Loc_sed.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.' gccosandvers (gccvers.U): If GNU cc (gcc) is used, this variable the operating system and version used to compile the gcc. It is set to '' if not gcc, or if nothing useful can be parsed as the os version. gccversion (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. gidformat (gidf.U): This variable contains the format string used for printing a Gid_t. gidsign (gidsign.U): This variable contains the signedness of a gidtype. 1 for unsigned, -1 for signed. gidsize (gidsize.U): This variable contains the size of a gidtype in bytes. gidtype (gidtype.U): This variable defines Gid_t to be something like gid_t, 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 (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. grep (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 (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 (groupstype.U): This variable defines Groups_t to be something like gid_t, int, ushort, or whatever type is used for the second argument to getgroups() and setgroups(). Usually, this is the same as gidtype (gid_t), but sometimes it isn't. gzip (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_fcntl (h_fcntl.U): This is variable gets set in various places to tell i_fcntl that should be included. h_sysfile (h_sysfile.U): This is variable gets set in various places to tell i_sys_file that should be included. hint (Oldconfig.U): Gives the type of hints used for previous answers. May be one of "default", "recommended" or "previous". hostcat (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. i16size (perlxv.U): This variable is the size of an I16 in bytes. i16type (perlxv.U): This variable contains the C type used for Perl's I16. i32size (perlxv.U): This variable is the size of an I32 in bytes. i32type (perlxv.U): This variable contains the C type used for Perl's I32. i64size (perlxv.U): This variable is the size of an I64 in bytes. i64type (perlxv.U): This variable contains the C type used for Perl's I64. i8size (perlxv.U): This variable is the size of an I8 in bytes. i8type (perlxv.U): This variable contains the C type used for Perl's I8. i_arpainet (i_arpainet.U): This variable conditionally defines the I_ARPA_INET symbol, and indicates whether a C program should include . i_bsdioctl (i_sysioctl.U): This variable conditionally defines the I_SYS_BSDIOCTL symbol, which indicates to the C program that exists and should be included. i_db (i_db.U): This variable conditionally defines the I_DB symbol, and indicates whether a C program may include Berkeley's DB include file . i_dbm (i_dbm.U): This variable conditionally defines the I_DBM symbol, which indicates to the C program that exists and should be included. i_dirent (i_dirent.U): This variable conditionally defines I_DIRENT, which indicates to the C program that it should include . i_dld (i_dld.U): This variable conditionally defines the I_DLD symbol, which indicates to the C program that (GNU dynamic loading) exists and should be included. i_dlfcn (i_dlfcn.U): This variable conditionally defines the I_DLFCN symbol, which indicates to the C program that exists and should be included. i_fcntl (i_fcntl.U): This variable controls the value of I_FCNTL (which tells the C program to include ). i_float (i_float.U): This variable conditionally defines the I_FLOAT symbol, and indicates whether a C program may include to get symbols like DBL_MAX or DBL_MIN, i.e. machine dependent floating point values. i_gdbm (i_gdbm.U): This variable conditionally defines the I_GDBM symbol, which indicates to the C program that exists and should be included. i_grp (i_grp.U): This variable conditionally defines the I_GRP symbol, and indicates whether a C program should include . i_iconv (i_iconv.U): This variable conditionally defines the I_ICONV symbol, and indicates whether a C program should include . i_ieeefp (i_ieeefp.U): This variable conditionally defines the I_IEEEFP symbol, and indicates whether a C program should include . i_inttypes (i_inttypes.U): This variable conditionally defines the I_INTTYPES symbol, and indicates whether a C program should include . i_libutil (i_libutil.U): This variable conditionally defines the I_LIBUTIL symbol, and indicates whether a C program should include . i_limits (i_limits.U): This variable conditionally defines the I_LIMITS symbol, and indicates whether a C program may include to get symbols like WORD_BIT and friends. i_locale (i_locale.U): This variable conditionally defines the I_LOCALE symbol, and indicates whether a C program should include . i_machcthr (i_machcthr.U): This variable conditionally defines the I_MACH_CTHREADS symbol, and indicates whether a C program should include . i_malloc (i_malloc.U): This variable conditionally defines the I_MALLOC symbol, and indicates whether a C program should include . i_math (i_math.U): This variable conditionally defines the I_MATH symbol, and indicates whether a C program may include . i_memory (i_memory.U): This variable conditionally defines the I_MEMORY symbol, and indicates whether a C program should include . i_mntent (i_mntent.U): This variable conditionally defines the I_MNTENT symbol, and indicates whether a C program should include . i_ndbm (i_ndbm.U): This variable conditionally defines the I_NDBM symbol, which indicates to the C program that exists and should be included. i_netdb (i_netdb.U): This variable conditionally defines the I_NETDB symbol, and indicates whether a C program should include . i_neterrno (i_neterrno.U): This variable conditionally defines the I_NET_ERRNO symbol, which indicates to the C program that exists and should be included. i_netinettcp (i_netinettcp.U): This variable conditionally defines the I_NETINET_TCP symbol, and indicates whether a C program should include . i_niin (i_niin.U): This variable conditionally defines I_NETINET_IN, which indicates to the C program that it should include . Otherwise, you may try . i_poll (i_poll.U): This variable conditionally defines the I_POLL symbol, and indicates whether a C program should include . i_prot (i_prot.U): This variable conditionally defines the I_PROT symbol, and indicates whether a C program should include . i_pthread (i_pthread.U): This variable conditionally defines the I_PTHREAD symbol, and indicates whether a C program should include . i_pwd (i_pwd.U): This variable conditionally defines I_PWD, which indicates to the C program that it should include . i_rpcsvcdbm (i_dbm.U): This variable conditionally defines the I_RPCSVC_DBM symbol, which indicates to the C program that exists and should be included. Some System V systems might need this instead of . i_sfio (i_sfio.U): This variable conditionally defines the I_SFIO symbol, and indicates whether a C program should include . i_sgtty (i_termio.U): This variable conditionally defines the I_SGTTY symbol, which indicates to the C program that it should include rather than . i_shadow (i_shadow.U): This variable conditionally defines the I_SHADOW symbol, and indicates whether a C program should include . i_socks (i_socks.U): This variable conditionally defines the I_SOCKS symbol, and indicates whether a C program should include . i_stdarg (i_varhdr.U): This variable conditionally defines the I_STDARG symbol, which indicates to the C program that exists and should be included. i_stddef (i_stddef.U): This variable conditionally defines the I_STDDEF symbol, which indicates to the C program that exists and should be included. i_stdlib (i_stdlib.U): This variable conditionally defines the I_STDLIB symbol, which indicates to the C program that exists and should be included. i_string (i_string.U): This variable conditionally defines the I_STRING symbol, which indicates that should be included rather than . i_sunmath (i_sunmath.U): This variable conditionally defines the I_SUNMATH symbol, and indicates whether a C program should include . i_sysaccess (i_sysaccess.U): This variable conditionally defines the I_SYS_ACCESS symbol, and indicates whether a C program should include . i_sysdir (i_sysdir.U): This variable conditionally defines the I_SYS_DIR symbol, and indicates whether a C program should include . i_sysfile (i_sysfile.U): This variable conditionally defines the I_SYS_FILE symbol, and indicates whether a C program should include to get R_OK and friends. i_sysfilio (i_sysioctl.U): This variable conditionally defines the I_SYS_FILIO symbol, which indicates to the C program that exists and should be included in preference to . i_sysin (i_niin.U): This variable conditionally defines I_SYS_IN, which indicates to the C program that it should include instead of . i_sysioctl (i_sysioctl.U): This variable conditionally defines the I_SYS_IOCTL symbol, which indicates to the C program that exists and should be included. i_syslog (i_syslog.U): This variable conditionally defines the I_SYSLOG symbol, and indicates whether a C program should include . i_sysmman (i_sysmman.U): This variable conditionally defines the I_SYS_MMAN symbol, and indicates whether a C program should include . i_sysmode (i_sysmode.U): This variable conditionally defines the I_SYSMODE symbol, and indicates whether a C program should include . i_sysmount (i_sysmount.U): This variable conditionally defines the I_SYSMOUNT symbol, and indicates whether a C program should include . i_sysndir (i_sysndir.U): This variable conditionally defines the I_SYS_NDIR symbol, and indicates whether a C program should include . i_sysparam (i_sysparam.U): This variable conditionally defines the I_SYS_PARAM symbol, and indicates whether a C program should include . i_sysresrc (i_sysresrc.U): This variable conditionally defines the I_SYS_RESOURCE symbol, and indicates whether a C program should include . i_syssecrt (i_syssecrt.U): This variable conditionally defines the I_SYS_SECURITY symbol, and indicates whether a C program should include . i_sysselct (i_sysselct.U): This variable conditionally defines I_SYS_SELECT, which indicates to the C program that it should include in order to get the definition of struct timeval. i_syssockio (i_sysioctl.U): This variable conditionally defines I_SYS_SOCKIO to indicate to the C program that socket ioctl codes may be found in instead of . i_sysstat (i_sysstat.U): This variable conditionally defines the I_SYS_STAT symbol, and indicates whether a C program should include . i_sysstatfs (i_sysstatfs.U): This variable conditionally defines the I_SYSSTATFS symbol, and indicates whether a C program should include . i_sysstatvfs (i_sysstatvfs.U): This variable conditionally defines the I_SYSSTATVFS symbol, and indicates whether a C program should include . i_systime (i_time.U): This variable conditionally defines I_SYS_TIME, which indicates to the C program that it should include . i_systimek (i_time.U): This variable conditionally defines I_SYS_TIME_KERNEL, which indicates to the C program that it should include with KERNEL defined. i_systimes (i_systimes.U): This variable conditionally defines the I_SYS_TIMES symbol, and indicates whether a C program should include . i_systypes (i_systypes.U): This variable conditionally defines the I_SYS_TYPES symbol, and indicates whether a C program should include . i_sysuio (i_sysuio.U): This variable conditionally defines the I_SYSUIO symbol, and indicates whether a C program should include . i_sysun (i_sysun.U): This variable conditionally defines I_SYS_UN, which indicates to the C program that it should include to get UNIX domain socket definitions. i_sysutsname (i_sysutsname.U): This variable conditionally defines the I_SYSUTSNAME symbol, and indicates whether a C program should include . i_sysvfs (i_sysvfs.U): This variable conditionally defines the I_SYSVFS symbol, and indicates whether a C program should include . i_syswait (i_syswait.U): This variable conditionally defines I_SYS_WAIT, which indicates to the C program that it should include . i_termio (i_termio.U): This variable conditionally defines the I_TERMIO symbol, which indicates to the C program that it should include rather than . i_termios (i_termio.U): This variable conditionally defines the I_TERMIOS symbol, which indicates to the C program that the POSIX file is to be included. i_time (i_time.U): This variable conditionally defines I_TIME, which indicates to the C program that it should include . i_unistd (i_unistd.U): This variable conditionally defines the I_UNISTD symbol, and indicates whether a C program should include . i_ustat (i_ustat.U): This variable conditionally defines the I_USTAT symbol, and indicates whether a C program should include . i_utime (i_utime.U): This variable conditionally defines the I_UTIME symbol, and indicates whether a C program should include . i_values (i_values.U): This variable conditionally defines the I_VALUES symbol, and indicates whether a C program may include to get symbols like MAXLONG and friends. i_varargs (i_varhdr.U): This variable conditionally defines I_VARARGS, which indicates to the C program that it should include . i_varhdr (i_varhdr.U): Contains the name of the header to be included to get va_dcl definition. Typically one of varargs.h or stdarg.h. i_vfork (i_vfork.U): This variable conditionally defines the I_VFORK symbol, and indicates whether a C program should include vfork.h. ignore_versioned_solibs (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). inc_version_list (inc_version_list.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 site_perl directory was introduced in 5.005, so that is the lowest possible value. inc_version_list_init (inc_version_list.U): This variable holds the same list as inc_version_list, but each item is enclosed in double quotes and separated by commas, suitable for use in the PERL_INC_VERSION_LIST initialization. incpath (usrinc.U): This variable must preceed the normal include path to get hte right one, as in "$incpath/usr/include" or "$incpath/usr/lib". Value can be "" or "/bsd43" on mips. inews (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. installarchlib (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 (bin.U): This variable is the same as binexp unless AFS is running in which case the user is explicitely prompted for it. This variable should always be used in your makefiles for maximum portability. installman1dir (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 (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 (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 (installprefix.U): This variable holds the full absolute path of installprefix with all ~-expansion done. installprivlib (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 (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 (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 (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. installsitelib (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. installstyle (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. 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 (instubperl.U): This variable tells whether Perl should be installed also as /usr/bin/perl in addition to $installbin/perl installvendorarch (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 (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. installvendorlib (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. intsize (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 (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 (perlxvf.U): This variable contains the format string used for printing a Perl IV as a signed decimal integer. ivsize (perlxv.U): This variable is the size of an IV in bytes. ivtype (perlxv.U): This variable contains the C type used for Perl's IV. known_extensions (Extensions.U): This variable holds a list of all XS extensions included in the package. ksh (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. ld (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. lddlflags (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 (ccflags.U): This variable contains any additional C loader flags desired by the user. It is up to the Makefile to use this. ldflags_uselargefiles (uselfs.U): This variable contains the loader flags needed by large file builds and added to ldflags by hints files. ldlibpthname (libperl.U): This variable holds the name of the shared library search path, often LD_LIBRARY_PATH. To get an empty string, the hints file must set this to 'none'. less (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. lib_ext (Unix.U): This is an old synonym for _a. libc (libc.U): This variable contains the location of the C library. libperl (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 (libpth.U): This variable holds the general path (space-separated) used to find libraries. It is intended to be used by other units. libs (libs.U): This variable holds the additional libraries we want to use. It is up to the Makefile to deal with it. libsdirs (libs.U): This variable holds the directory names aka dirnames of the libraries we found and accepted, duplicates are removed. libsfiles (libs.U): This variable holds the filenames aka basenames of the libraries we found and accepted. libsfound (libs.U): This variable holds the full pathnames of the libraries we found and accepted. libspath (libs.U): This variable holds the directory names probed for libraries. libswanted (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. libswanted_uselargefiles (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 (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. lint (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. lkflags (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 (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 (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' locincpth (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 (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 (d_longdbl.U): This variable contains the value of the LONG_DOUBLESIZE symbol, which indicates to the C program how many bytes there are in a long double, if this system supports long doubles. longlongsize (d_longlong.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 (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 (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. lpr (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. ls (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 (lseektype.U): This variable defines lseektype to be something like off_t, 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 (lseektype.U): This variable defines lseektype to be something like off_t, long, or whatever type is used to declare lseek offset's type in the kernel (which also appears to be lseek's return type). mail (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. mailx (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. make (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. make_set_make (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: make_set_make='#' # If your make program handles this for you, make_set_make="MAKE=$make" # if it doesn't. I used 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 (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 (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 (mallocsrc.U): This variable contains the kind of ptr returned by malloc and realloc. man1dir (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 (man1dir.U): This variable is the same as the man1dir variable, but is filename expanded at configuration time, for convenient use in makefiles. man1ext (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 (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 (man3dir.U): This variable is the same as the man3dir variable, but is filename expanded at configuration time, for convenient use in makefiles. man3ext (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. Mcc (Loc.U): This variable is used internally by Configure to determine the full pathname (if any) of the Mcc program. After Configure runs, the value is reset to a plain "Mcc" and is not useful. mips_type (usrinc.U): This variable holds the environment type for the mips system. Possible values are "BSD 4.3" and "System V". mkdir (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 (d_mmap.U): This symbol contains the type of pointer returned by mmap() (and simultaneously the type of the first argument). It can be 'void *' or 'caddr_t'. modetype (modetype.U): This variable defines modetype to be something like mode_t, int, unsigned short, or whatever type is used to declare file modes for system calls. more (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 (multiarch.U): This variable conditionally defines the MULTIARCH symbol which signifies the presence of multiplatform files. This is normally set by hints files. mv (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. myarchname (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 (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 (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 (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.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". need_va_copy (need_va_copy.U): This symbol, if defined, indicates that the system stores the variable argument list datatype, va_list, 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, Perl_va_copy(src, dst), to do the job. netdb_hlen_type (netdbtype.U): This variable holds the type used for the 2nd argument to gethostbyaddr(). Usually, this is int or size_t or unsigned. This is only useful if you have gethostbyaddr(), naturally. netdb_host_type (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. netdb_name_type (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. netdb_net_type (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 (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. nm_opt (usenm.U): This variable holds the options that may be necessary for nm. nm_so_opt (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. nonxs_ext (Extensions.U): This variable holds a list of all non-xs extensions included in the package. All of them will be built. nroff (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. nveformat (perlxvf.U): This variable contains the format string used for printing a Perl NV using %e-ish floating point format. nvEUformat (perlxvf.U): This variable contains the format string used for printing a Perl NV using %E-ish floating point format. nvfformat (perlxvf.U): This variable confains the format string used for printing a Perl NV using %f-ish floating point format. nvFUformat (perlxvf.U): This variable confains the format string used for printing a Perl NV using %F-ish floating point format. nvgformat (perlxvf.U): This variable contains the format string used for printing a Perl NV using %g-ish floating point format. nvGUformat (perlxvf.U): This variable contains the format string used for printing a Perl NV using %G-ish floating point format. nvsize (perlxv.U): This variable is the size of an NV in bytes. nvtype (perlxv.U): This variable contains the C type used for Perl's NV. o_nonblock (nblock_io.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. obj_ext (Unix.U): This is an old synonym for _o. old_pthread_create_joinable (d_pthrattrj.U): This variable defines the constant to use for creating joinable (aka undetached) pthreads. Unused if pthread.h defines PTHREAD_CREATE_JOINABLE. If used, possible values are PTHREAD_CREATE_UNDETACHED and __UNDETACHED. optimize (ccflags.U): This variable contains any optimizer/debugger flag that should be used. It is up to the Makefile to use it. orderlib (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 (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 (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 os_4.0 or os_4.1, etc., not keeping separate files for each little release. otherlibdirs (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 inc_version_list for more details. A value of ' ' means 'none' and is used to preserve this value for the next run through Configure. package (package.U): This variable contains the name of the package being constructed. It is primarily intended for the use of later Configure units. pager (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 (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 (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 "PERL_VERSION". path_sep (Unix.U): This is an old synonym for p_ in Head.U, the character used to separate elements in the command shell search PATH. perl5 (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 inc_version_list. perl (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. perl_patchlevel (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. PERL_REVISION (Oldsyms.U): In a Perl version number such as 5.6.2, this is the 5. This value is manually set in patchlevel.h PERL_SUBVERSION (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 PERL_VERSION (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 (perladmin.U): Electronic mail address of the perl5 administrator. perllibs (End.U): The list of libraries needed by Perl only (any libraries needed by extensions only will by dropped, if using dynamic loading). perlpath (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. pg (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 (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 (pidtype.U): This variable defines PIDTYPE to be something like pid_t, int, ushort, or whatever type is used to declare process ids in the kernel. plibpth (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. pm_apiversion (xs_apiversion.U): This variable contains the version of the oldest perl compatible with the present perl. (That is, pure perl modules written for $pm_apiversion will still work for the current version). perl.c:incpush() and lib/lib.pm will automatically search in $sitelib for older directories across major versions back to pm_apiversion. This is only useful if you have a perl library directory tree structured like the default one. The versioned site_perl library was introduced in 5.005, so that's the default setting for this variable. It's hard to imagine it changing before Perl6. It is included here for symmetry with xs_apiveprsion -- the searching algorithms will (presumably) be similar. See the INSTALL file for how this works. pmake (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. pr (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. prefix (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 (prefix.U): This variable holds the full absolute path of the directory below which the user will install the package. Derived from prefix. privlib (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 (privlib.U): This variable is the ~name expanded version of privlib, so that you may use it directly in Makefiles or shell scripts. prototype (prototype.U): This variable holds the eventual value of CAN_PROTOTYPE, which indicates the C compiler can handle funciton prototypes. ptrsize (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. quadkind (quadtype.U): This variable, if defined, encodes the type of a quad: 1 = int, 2 = long, 3 = long long, 4 = int64_t. quadtype (quadtype.U): This variable defines Quad_t to be something like long, int, long long, int64_t, or whatever type is used for 64-bit integers. randbits (randfunc.U): Indicates how many bits are produced by the function used to generate normalized random numbers. randfunc (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). randseedtype (randfunc.U): Indicates the type of the argument of the seedfunc. ranlib (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 rd_nodata (nblock_io.U): This variable holds the return code from read() when no data is present. It should be -1, but some systems return 0 when O_NDELAY is used, which is a shame because you cannot make the difference between no data and an EOF.. Sigh! revision (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 "PERL_REVISION". rm (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. rmail (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. runnm (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. sched_yield (d_pthread_y.U): This variable defines the way to yield the execution of the current thread. scriptdir (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 (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 (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 (randfunc.U): Indicates the random number generating seed function. Values include srand48, srandom, and srand. selectminbits (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 (selecttype.U): This variable holds the type used for the 2nd, 3rd, and 4th arguments to select. Usually, this is 'fd_set *', if HAS_FD_SET is defined, and 'int *' otherwise. This is only useful if you have select(), naturally. sendmail (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. sh (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 (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. sharpbang (spitshell.U): This variable contains the string #! if this system supports that construct. shmattype (d_shmat.U): This symbol contains the type of pointer returned by shmat(). It can be 'void *' or 'char *'. shortsize (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 (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 LD_RUN_PATH 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 $libs Typical values are shrpenv="env LD_RUN_PATH=$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, NetBSD) or -Wl,-rpath $archlibexp/CORE (Linux). shsharp (spitshell.U): This variable tells further Configure units whether your sh can handle # comments. sig_count (sig_name.U): This variable holds a number larger than the largest valid signal number. This is usually the same as the NSIG macro. sig_name (sig_name.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. sig_name_init (sig_name.U): This variable holds the signal names, enclosed in double quotes and separated by commas, suitable for use in the SIG_NAME 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 sig_num. sig_num (sig_name.U): This variable holds the signal numbers, space separated. A ZERO is prepended to the list (corresponding to the fake SIGZERO), and the list is terminated with a 0. Those numbers correspond to the value of the signal listed in the same place within the sig_name list. sig_num_init (sig_name.U): This variable holds the signal numbers, enclosed in double quotes and separated by commas, suitable for use in the SIG_NUM definition below. A "ZERO" is prepended to the list, and the list is terminated with a plain 0. sig_size (sig_name.U): This variable contains the number of elements of the sig_name and sig_num arrays, excluding the final NULL entry. signal_t (d_voidsig.U): This variable holds the type of the signal handler (void or int). sitearch (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 (sitearch.U): This variable is the ~name expanded version of sitearch, so that you may use it directly in Makefiles or shell scripts. sitebin (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 (sitebin.U): This is the same as the sitebin variable, but is filename expanded at configuration time, for use in your makefiles. sitelib (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. sitelib_stem (sitelib.U): This variable is $sitelibexp with any trailing version-specific component removed. The elements in inc_version_list (inc_version_list.U) can be tacked onto this variable to generate a list of directories to search. sitelibexp (sitelib.U): This variable is the ~name expanded version of sitelib, so that you may use it directly in Makefiles or shell scripts. siteprefix (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 (siteprefix.U): This variable holds the full absolute path of the directory below which the user will install add-on packages. Derived from siteprefix. sizesize (sizesize.U): This variable contains the size of a sizetype in bytes. sizetype (sizetype.U): This variable defines sizetype to be something like size_t, unsigned long, or whatever type is used to declare length parameters for string functions. sleep (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. smail (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. so (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 (d_socket.U): This variable has any cpp '-I' flags needed for socket support. socketlib (d_socket.U): This variable has the names of any libraries needed for socket support. socksizetype (socksizetype.U): This variable holds the type used for the size argument for various socket calls like accept. Usual values include socklen_t, size_t, and int. sort (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 (package.U): This variable contains the name of the package being constructed, with the first letter uppercased, i.e. suitable for starting sentences. spitshell (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 (quadfio.U): This variable, if defined, contains the string used by stdio to format 64-bit decimal numbers (format 'd') for output. sPRIeldbl (longdblfio.U): This variable, if defined, contains the string used by stdio to format long doubles (format 'e') for output. sPRIEUldbl (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 (longdblfio.U): This variable, if defined, contains the string used by stdio to format long doubles (format 'f') for output. sPRIFUldbl (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 (longdblfio.U): This variable, if defined, contains the string used by stdio to format long doubles (format 'g') for output. sPRIGUldbl (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 (quadfio.U): This variable, if defined, contains the string used by stdio to format 64-bit decimal numbers (format 'i') for output. sPRIo64 (quadfio.U): This variable, if defined, contains the string used by stdio to format 64-bit octal numbers (format 'o') for output. sPRIu64 (quadfio.U): This variable, if defined, contains the string used by stdio to format 64-bit unsigned decimal numbers (format 'u') for output. sPRIx64 (quadfio.U): This variable, if defined, contains the string used by stdio to format 64-bit hexadecimal numbers (format 'x') for output. sPRIXU64 (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. src (src.U): This variable holds the path to the package source. It is up to the Makefile to use this variable and set VPATH accordingly to find the sources remotely. sSCNfldbl (longdblfio.U): This variable, if defined, contains the string used by stdio to format long doubles (format 'f') for input. ssizetype (ssizetype.U): This variable defines ssizetype to be something like ssize_t, 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(SSize_t) == sizeof(Size_t). startperl (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 $running_under_some_shell; to guarantee perl startup should the shell execute the script. Note that this magic incatation is not understood by csh. startsh (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. static_ext (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 (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". stdio_base (d_stdstdio.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 FILE_base(fp). stdio_bufsiz (d_stdstdio.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 FILE_bufsiz(fp). stdio_cnt (d_stdstdio.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 FILE_cnt(fp). stdio_filbuf (d_stdstdio.U): This variable defines how, given a FILE pointer, fp, to tell stdio to refill it's internal buffers (?). This will be used to define the macro FILE_filbuf(fp). stdio_ptr (d_stdstdio.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 FILE_ptr(fp). stdio_stream_array (stdio_streams.U): This variable tells the name of the array holding the stdio streams. Usual values include _iob, __iob, and __sF. strings (i_string.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 (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. subversion (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 "PERL_SUBVERSION". This is unique to perl. sysman (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. tail (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. tar (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. tbl (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. tee (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. test (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 (i_time.U): This variable holds the full path of the included time header(s). timetype (d_time.U): This variable holds the type returned by time(). It can be long, or time_t on BSD sites (in which case should be included). Anyway, the type Time_t should be used. touch (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 (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 (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 (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. u16size (perlxv.U): This variable is the size of an U16 in bytes. u16type (perlxv.U): This variable contains the C type used for Perl's U16. u32size (perlxv.U): This variable is the size of an U32 in bytes. u32type (perlxv.U): This variable contains the C type used for Perl's U32. u64size (perlxv.U): This variable is the size of an U64 in bytes. u64type (perlxv.U): This variable contains the C type used for Perl's U64. u8size (perlxv.U): This variable is the size of an U8 in bytes. u8type (perlxv.U): This variable contains the C type used for Perl's U8. uidformat (uidf.U): This variable contains the format string used for printing a Uid_t. uidsign (uidsign.U): This variable contains the signedness of a uidtype. 1 for unsigned, -1 for signed. uidsize (uidsize.U): This variable contains the size of a uidtype in bytes. uidtype (uidtype.U): This variable defines Uid_t to be something like uid_t, int, ushort, or whatever type is used to declare user ids in the kernel. uname (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 (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 (quadtype.U): This variable defines Uquad_t to be something like unsigned long, unsigned int, unsigned long long, uint64_t, or whatever type is used for 64-bit integers. use5005threads (usethreads.U): This variable conditionally defines the USE_5005THREADS symbol, and indicates that Perl should be built to use the 5.005-based threading implementation. use64bitall (use64bits.U): This variable conditionally defines the USE_64_BIT_ALL 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 USE_64_BIT_INT. 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 (use64bits.U): This variable conditionally defines the USE_64_BIT_INT 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. usedl (dlsrc.U): This variable indicates if the system supports dynamic loading of some sort. See also dlsrc and dlobj. useithreads (usethreads.U): This variable conditionally defines the USE_ITHREADS symbol, and indicates that Perl should be built to use the interpreter-based threading implementation. uselargefiles (uselfs.U): This variable conditionally defines the USE_LARGE_FILES symbol, and indicates that large file interfaces should be used when available. uselongdouble (uselongdbl.U): This variable conditionally defines the USE_LONG_DOUBLE symbol, and indicates that long doubles should be used when available. usemorebits (usemorebits.U): This variable conditionally defines the USE_MORE_BITS symbol, and indicates that explicit 64-bit interfaces and long doubles should be used when available. usemultiplicity (usemultiplicity.U): This variable conditionally defines the MULTIPLICITY symbol, and indicates that Perl should be built to use multiplicity. usemymalloc (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 effiency, but such versions are often less portable. See also mallocsrc and mallocobj. If this is 'y', then -lmalloc is removed from $libs. usenm (usenm.U): This variable contains 'true' or 'false' depending whether the nm extraction is wanted or not. useopcode (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 (useperlio.U): This variable conditionally defines the USE_PERLIO symbol, and indicates that the PerlIO abstraction should be used throughout. useposix (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. usesfio (d_sfio.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 explicitely requests not to use sfio. It is here primarily so that command-line settings can override the auto-detection of d_sfio without running into a "WHOA THERE". useshrplib (libperl.U): This variable is set to 'yes' if the user wishes to build a shared libperl, and 'no' otherwise. usesocks (usesocks.U): This variable conditionally defines the USE_SOCKS symbol, and indicates that Perl should be built to use SOCKS. usethreads (usethreads.U): This variable conditionally defines the USE_THREADS symbol, and indicates that Perl should be built to use threads. usevendorprefix (vendorprefix.U): This variable tells whether the vendorprefix and consequently other vendor* paths are in use. usevfork (d_vfork.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 explicitely requests not to use vfork. usrinc (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 (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. uvoformat (perlxvf.U): This variable contains the format string used for printing a Perl UV as an unsigned octal integer. uvsize (perlxv.U): This variable is the size of a UV in bytes. uvtype (perlxv.U): This variable contains the C type used for Perl's UV. uvuformat (perlxvf.U): This variable contains the format string used for printing a Perl UV as an unsigned decimal integer. uvxformat (perlxvf.U): This variable contains the format string used for printing a Perl UV as an unsigned hexadecimal integer in lowercase abcdef. uvXUformat (perlxvf.U): This variable contains the format string used for printing a Perl UV as an unsigned hexadecimal integer in uppercase ABCDEF. vendorarch (vendorarch.U): This variable contains the value of the PERL_VENDORARCH 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 (vendorarch.U): This variable is the ~name expanded version of vendorarch, so that you may use it directly in Makefiles or shell scripts. vendorbin (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 (vendorbin.U): This variable is the ~name expanded version of vendorbin, so that you may use it directly in Makefiles or shell scripts. vendorlib (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. vendorlib_stem (vendorlib.U): This variable is $vendorlibexp with any trailing version-specific component removed. The elements in inc_version_list (inc_version_list.U) can be tacked onto this variable to generate a list of directories to search. vendorlibexp (vendorlib.U): This variable is the ~name expanded version of vendorlib, so that you may use it directly in Makefiles or shell scripts. vendorprefix (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 (vendorprefix.U): This variable holds the full absolute path of the directory below which the vendor will install add-on packages. Derived from vendorprefix. version (patchlevel.U): The full version number of this package, such as 5.6.1 (or 5_6_1). 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. versiononly (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 (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. voidflags (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. xlibpth (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. xs_apiversion (xs_apiversion.U): This variable contains the version of the oldest perl binary compatible with the present perl. perl.c:incpush() and lib/lib.pm will automatically search in $sitearch for older directories across major versions back to xs_apiversion. 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 site_perl directory was introduced in 5.005, so that is the lowest possible value. Since this can depend on compile time options (such as bincompat) it is set by Configure. Other non-default sources of potential incompatibility, such as multiplicity, threads, debugging, 64bits, sfio, etc., are not checked for currently, though in principle we could go snooping around in old Config.pm files. yacc (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 (yacc.U): This variable contains any additional yacc flags desired by the user. It is up to the Makefile to use this. zcat (Loc.U): This variable is defined but not used by Configure. The value is a plain '' and is not useful. zip (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.