From d_gconvert.U:

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

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

From longdblfio.U:

This variable conditionally defines the PERL_PRIfldbl symbol, which indicates 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.

From longdblfio.U:

This variable conditionally defines the PERL_PRIfldbl symbol, which indicates 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.

From longdblfio.U:

This variable conditionally defines the PERL_PRIfldbl symbol, which indicates 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.

From quadfio.U:

This variable conditionally defines the PERL_PRIXU64 symbol, which indicates 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.

From quadfio.U:

This variable conditionally defines the PERL_PRId64 symbol, which indicates that stdio has a symbol to print 64-bit decimal numbers.

From longdblfio.U:

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

From longdblfio.U:

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

From longdblfio.U:

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

From quadfio.U:

This variable conditionally defines the PERL_PRIi64 symbol, which indicates that stdio has a symbol to print 64-bit decimal numbers.

From quadfio.U:

This variable conditionally defines the PERL_PRIo64 symbol, which indicates that stdio has a symbol to print 64-bit octal numbers.

From quadfio.U:

This variable conditionally defines the PERL_PRIu64 symbol, which indicates that stdio has a symbol to print 64-bit unsigned decimal numbers.

From quadfio.U:

This variable conditionally defines the PERL_PRIx64 symbol, which indicates that stdio has a symbol to print 64-bit hexadecimal numbers.

From longdblfio.U:

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

From d__fwalk.U:

This variable conditionally defines HAS__FWALK if _fwalk() is available to apply a function to all the file handles.

From d_accept4.U:

This variable conditionally defines HAS_ACCEPT4 if accept4() is available to accept socket connections.

From d_access.U:

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

From d_accessx.U:

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

From d_acosh.U:

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

From d_aintl.U:

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

From d_alarm.U:

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

From archlib.U:

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

From d_timefuncs64.U:

This variable conditionally defines the HAS_ASCTIME64 symbol, which indicates to the C program that the asctime64 () routine is available.

From d_asctime_r.U:

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

From d_asinh.U:

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

From d_atanh.U:

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

From atolf.U:

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

From atoll.U:

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

From d_attribut.U:

This variable conditionally defines HASATTRIBUTE_ALWAYS_INLINE, which indicates that the C compiler can know that certain functions should always be inlined.

From d_attribut.U:

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

From d_attribut.U:

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

From d_attribut.U:

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

From d_attribut.U:

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

From d_attribut.U:

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

From d_attribut.U:

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

From d_attribut.U:

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

From d_attribut.U:

This variable conditionally defines the HASATTRIBUTE_VISIBILITY symbol, and indicates different GCC attribute visibility

From d_attribut.U:

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

From d_backtrace.U:

This variable conditionally defines the HAS_BACKTRACE symbol, which indicates to the C program that the backtrace() routine is available to get a stack trace.

From Guess.U:

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

From d_getpgrp.U:

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

From 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.

From d_builtin_overflow.U:

This variable conditionally defines HAS_BUILTIN_ADD_OVERFLOW, which indicates that the compiler supports __builtin_add_overflow(x,y,&z) for safely adding x and y into z while checking for overflow.

From d_builtin.U:

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

From d_builtin.U:

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

From d_builtin_overflow.U:

This variable conditionally defines HAS_BUILTIN_MUL_OVERFLOW, which indicates that the compiler supports __builtin_mul_overflow(x,y,&z) for safely multiplying x and y into z while checking for overflow.

From d_builtin_overflow.U:

This variable conditionally defines HAS_BUILTIN_SUB_OVERFLOW, which indicates that the compiler supports __builtin_sub_overflow(x,y,&z) for safely subtracting y from x into z while checking for overflow.

From d_c99_variadic.U:

This variable conditionally defines the HAS_C99_VARIADIC_MACROS symbol, which indicates to the C program that C99 variadic macros are available.

From d_casti32.U:

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

From d_castneg.U:

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

From d_cbrt.U:

This variable conditionally defines the HAS_CBRT symbol, which indicates to the C program that the cbrt() (cube root) function is available.

From d_chown.U:

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

From d_chroot.U:

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

From 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.

From d_class.U:

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

From d_clearenv.U:

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

From d_closedir.U:

This variable conditionally defines HAS_CLOSEDIR if closedir() is available.

From d_cmsghdr_s.U:

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

From d_copysign.U:

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

From d_copysignl.U:

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

From d_cplusplus.U:

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

From 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.

From d_crypt_r.U:

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

From d_csh.U:

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

From d_ctermid.U:

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

From d_ctermid_r.U:

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

From d_timefuncs64.U:

This variable conditionally defines the HAS_CTIME64 symbol, which indicates to the C program that the ctime64 () routine is available.

From d_ctime_r.U:

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

From 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.

From d_dbminitproto.U:

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

From d_difftime.U:

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

From d_timefuncs64.U:

This variable conditionally defines the HAS_DIFFTIME64 symbol, which indicates to the C program that the difftime64 () routine is available.

From d_dir_dd_fd.U:

This variable conditionally defines the HAS_DIR_DD_FD symbol, which indicates that the DIR directory stream type contains a member variable called dd_fd.

From d_dirfd.U:

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

From 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.

From d_dladdr.U:

This variable conditionally defines the HAS_DLADDR symbol, which indicates to the C program that the dladdr() routine is available to get a stack trace.

From d_dlerror.U:

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

From d_dlopen.U:

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

From 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().

From 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.

From longdblfio.U:

This variable conditionally defines the symbol DOUBLE_HAS_INF which indicates that the double type has an infinity.

From longdblfio.U:

This variable conditionally defines the symbol DOUBLE_HAS_NAN which indicates that the double type has a not-a-number.

From longdblfio.U:

This variable conditionally defines the symbol DOUBLE_HAS_NEGATIVE_ZERO which indicates that the double type has a negative zero.

From longdblfio.U:

This variable conditionally defines the symbol DOUBLE_HAS_SUBNORMALS which indicates that the double type has subnormals (denormals).

From longdblfio.U:

This variable conditionally defines the symbol DOUBLE_STYLE_CRAY which indicates that the double is the 64-bit CRAY mainframe format.

From longdblfio.U:

This variable conditionally defines the symbol DOUBLE_STYLE_IBM, which indicates that the double is the 64-bit IBM mainframe format.

From longdblfio.U:

This variable conditionally defines the symbol DOUBLE_STYLE_IEEE, which indicates that the double is the 64-bit IEEE 754.

From longdblfio.U:

This variable conditionally defines the symbol DOUBLE_STYLE_VAX, which indicates that the double is the 64-bit VAX format D or G.

From d_drand48_r.U:

This variable conditionally defines the HAS_DRAND48_R symbol, which indicates to the C program that the drand48_r() routine is available.

From 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.

From d_dup2.U:

This variable conditionally defines HAS_DUP2 if dup2() is available to duplicate file descriptors.

From d_dup3.U:

This variable conditionally defines HAS_DUP3 if dup3() is available to duplicate file descriptors.

From d_newlocale.U:

This variable conditionally defines the HAS_DUPLOCALE symbol, which indicates to the C program that the duplocale() routine is available to duplicate a locale object.

From d_eaccess.U:

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

From 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.

From d_endgrent_r.U:

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

From d_endhent.U:

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

From d_endhostent_r.U:

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

From d_endnent.U:

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

From d_endnetent_r.U:

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

From d_endpent.U:

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

From d_endprotoent_r.U:

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

From 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.

From d_endpwent_r.U:

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

From d_endsent.U:

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

From d_endservent_r.U:

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

From nblock_io.U:

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

From d_erf.U:

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

From d_erfc.U:

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

From Guess.U:

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

From d_exp2.U:

This variable conditionally defines the HAS_EXP2 symbol, which indicates to the C program that the exp2() routine is available.

From d_expm1.U:

This variable conditionally defines the HAS_EXPM1 symbol, which indicates to the C program that the expm1() routine is available.

From d_faststdio.U:

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

From d_fchdir.U:

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

From 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.

From d_fsat.U:

This variable conditionally defines the HAS_FCHMODAT symbol, which indicates the POSIX fchmodat() function is available.

From 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.

From d_fcntl.U:

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

From d_fcntl_can_lock.U:

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

From 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.

From 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.

From d_fdclose.U:

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

From d_fdim.U:

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

From d_fdopendir.U:

This variable conditionally defines the HAS_FORK symbol, which indicates that the fdopen routine is available to open a directory descriptor.

From 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.

From d_fegetround.U:

This variable conditionally defines HAS_FEGETROUND if fegetround() is available to get the floating point rounding mode.

From d_ffs.U:

This variable conditionally defines the HAS_FFS symbol, which indicates to the C program that the ffs() routine is available to find the first bit which is set in its integer argument.

From d_ffs.U:

This variable conditionally defines the HAS_FFSL symbol, which indicates to the C program that the ffsl() routine is available to find the first bit which is set in its long integer argument.

From d_fgetpos.U:

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

From d_finite.U:

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

From d_finitel.U:

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

From d_flexfnam.U:

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

From d_flock.U:

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

From d_flockproto.U:

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

From d_fma.U:

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

From d_fmax.U:

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

From d_fmin.U:

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

From d_fork.U:

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

From d_fp_class.U:

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

From d_fpclassify.U:

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

From d_fp_classl.U:

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

From 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.

From d_fpclass.U:

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

From d_fpclassify.U:

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

From d_fpclassl.U:

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

From d_fpgetround.U:

This variable conditionally defines HAS_FPGETROUND if fpgetround() is available to get the floating point rounding mode.

From d_fpos64_t.U:

This symbol will be defined if the C compiler supports fpos64_t.

From d_newlocale.U:

This variable conditionally defines the HAS_FREELOCALE symbol, which indicates to the C program that the freelocale() routine is available to deallocates the resources associated with a locale object.

From d_frexpl.U:

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

From d_fs_data_s.U:

This variable conditionally defines the HAS_STRUCT_FS_DATA symbol, which indicates that the struct fs_data is supported.

From d_fseeko.U:

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

From d_fsetpos.U:

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

From d_fstatfs.U:

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

From d_statvfs.U:

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

From d_fsync.U:

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

From d_ftello.U:

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

From 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.

From d_futimes.U:

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

From d_gai_strerror.U:

This variable conditionally defines the HAS_GAI_STRERROR symbol if the gai_strerror() routine is available and can be used to translate error codes returned by getaddrinfo() into human readable strings.

From i_ndbm.U:

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

From i_ndbm.U:

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

From d_getaddrinfo.U:

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

From 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.

From d_getenv_thread.U:

This variable conditionally defines the GETENV_PRESERVES_OTHER_THREAD symbol, which indicates to the C program that the getenv() system call does not zap the static buffer in a different thread.

From d_getespwnam.U:

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

From d_getfsstat.U:

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

From 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.

From d_getgrent_r.U:

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

From d_getgrgid_r.U:

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

From d_getgrnam_r.U:

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

From 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.

From 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.

From 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.

From d_gethent.U:

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

From 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.

From d_gethostbyaddr_r.U:

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

From d_gethostbyname_r.U:

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

From d_gethostent_r.U:

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

From d_gethostprotos.U:

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

From d_getitimer.U:

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

From 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.

From d_getlogin_r.U:

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

From 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.

From 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.

From d_getnameinfo.U:

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

From 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.

From 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.

From d_getnent.U:

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

From d_getnetbyaddr_r.U:

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

From d_getnetbyname_r.U:

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

From d_getnetent_r.U:

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

From d_getnetprotos.U:

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

From d_getpagsz.U:

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

From 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.

From 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.

From d_getpent.U:

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

From 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.

From d_getpgrp.U:

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

From 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.

From 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.

From d_getprior.U:

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

From d_getprotobyname_r.U:

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

From d_getprotobynumber_r.U:

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

From d_getprotoent_r.U:

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

From d_getprotoprotos.U:

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

From d_getprpwnam.U:

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

From 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.

From d_getpwent_r.U:

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

From d_getpwnam_r.U:

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

From d_getpwuid_r.U:

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

From 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.

From 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.

From d_getsent.U:

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

From d_getservbyname_r.U:

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

From d_getservbyport_r.U:

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

From d_getservent_r.U:

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

From d_getservprotos.U:

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

From d_getspnam.U:

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

From d_getspnam_r.U:

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

From 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 <sys/resource.h>.

From d_timefuncs64.U:

This variable conditionally defines the HAS_GMTIME64 symbol, which indicates to the C program that the gmtime64 () routine is available.

From d_gmtime_r.U:

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

From d_gnulibc.U:

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

From i_grp.U:

This variable conditionally defines GRPASSWD, which indicates that struct group in <grp.h> contains gr_passwd.

From d_setlocale.U:

This variable is set to either true or false depending on whether the compilation system supports the C.UTF-8 locale.

From 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.

From d_htonl.U:

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

From d_hypot.U:

This variable conditionally defines HAS_HYPOT if hypot is available for numerically stable hypotenuse function.

From d_ilogb.U:

This variable conditionally defines the HAS_ILOGB symbol, which indicates to the C program that the ilogb() routine is available for extracting the exponent of double x as a signed integer.

From d_ilogbl.U:

This variable conditionally defines the HAS_ILOGBL symbol, which indicates to the C program that the ilogbl() routine is available for extracting the exponent of long double x as a signed integer. If scalbnl is also present we can emulate frexpl.

From inc_version_list.U:

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

From 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.

From d_inetntop.U:

This variable conditionally defines the HAS_INETNTOP symbol, which indicates to the C program that the inet_ntop() function is available.

From d_inetpton.U:

This variable conditionally defines the HAS_INETPTON symbol, which indicates to the C program that the inet_pton() function is available.

From d_int64_t.U:

This symbol will be defined if the C compiler supports int64_t.

From d_socket.U:

This variable conditionally defines the HAS_IP_MREQ symbol, which indicates the availability of a struct ip_mreq.

From d_socket.U:

This variable conditionally defines the HAS_IP_MREQ_SOURCE symbol, which indicates the availability of a struct ip_mreq_source.

From d_socket.U:

This variable conditionally defines the HAS_IPV6_MREQ symbol, which indicates the availability of a struct ipv6_mreq.

From d_socket.U:

This variable conditionally defines the HAS_IPV6_MREQ_SOURCE symbol, which indicates the availability of a struct ipv6_mreq_source.

From d_isascii.U:

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

From d_isblank.U:

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

From d_isfinite.U:

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

From d_isfinitel.U:

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

From d_isinf.U:

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

From d_isinfl.U:

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

From d_isless.U:

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

From d_isnan.U:

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

From d_isnanl.U:

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

From d_isnormal.U:

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

From d_j0.U:

This variable conditionally defines the HAS_J0 symbol, which indicates to the C program that the j0() routine is available.

From d_j0.U:

This variable conditionally defines the HAS_J0L symbol, which indicates to the C program that the j0l() routine is available.

From 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.

From d_lc_monetary_2008.U:

This variable conditionally defines HAS_LC_MONETARY_2008 if libc has the international currency locale rules from POSIX 1003.1-2008.

From 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).

From 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.

From d_longdbl.U:

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

From d_lgamma.U:

This variable conditionally defines the HAS_LGAMMA symbol, which indicates to the C program that the lgamma() routine is available for the log gamma function. See also d_tgamma and d_lgamma_r.

From d_lgamma_r.U:

This variable conditionally defines the HAS_LGAMMA_R symbol, which indicates to the C program that the lgamma_r() routine is available for the log gamma function, without using the global signgam variable.

From d_libm_lib_version.U:

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

From so.U:

This variable is defined if the target system insists on unique basenames for shared library files. This is currently true on Android, false everywhere else we know of. Defaults to undef.

From d_link.U:

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

From d_fsat.U:

This variable conditionally defines the HAS_LINKAT symbol, which indicates the POSIX linkat() function is available.

From d_llrint.U:

This variable conditionally defines the HAS_LLRINT symbol, which indicates to the C program that the llrint() routine is available to return the long long value closest to a double (according to the current rounding mode).

From d_llrintl.U:

This variable conditionally defines the HAS_LLRINTL symbol, which indicates to the C program that the llrintl() routine is available to return the long long value closest to a long double (according to the current rounding mode).

From d_llround.U:

This variable conditionally defines the HAS_LLROUND symbol, which indicates to the C program that the llround() routine is available to return the long long value nearest to x.

From d_llroundl.U:

This variable conditionally defines the HAS_LLROUNDL symbol, which indicates to the C program that the llroundl() routine is available to return the long long value nearest to x away from zero.

From d_localeconv_l.U:

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

From d_timefuncs64.U:

This variable conditionally defines the HAS_LOCALTIME64 symbol, which indicates to the C program that the localtime64 () routine is available.

From d_localtime_r.U:

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

From d_localtime_r.U:

This variable conditionally defines the LOCALTIME_R_NEEDS_TZSET symbol, which makes us call tzset before localtime_r()

From d_locconv.U:

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

From d_lockf.U:

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

From d_log1p.U:

This variable conditionally defines the HAS_LOG1P symbol, which indicates to the C program that the logp1() routine is available to compute log(1 + x) for values of x close to zero.

From d_log2.U:

This variable conditionally defines the HAS_LOG2 symbol, which indicates to the C program that the log2() routine is available to compute log base two.

From d_logb.U:

This variable conditionally defines the HAS_LOGB symbol, which indicates to the C program that the logb() routine is available to extract the exponent of x.

From d_longdbl.U:

This variable conditionally defines LONG_DOUBLE_STYLE_IEEE if the long double is any of the IEEE 754 style long doubles: LONG_DOUBLE_STYLE_IEEE_STD, LONG_DOUBLE_STYLE_IEEE_EXTENDED, LONG_DOUBLE_STYLE_IEEE_DOUBLEDOUBLE.

From d_longdbl.U:

This variable conditionally defines LONG_DOUBLE_STYLE_IEEE_DOUBLEDOUBLE if the long double is the 128-bit IEEE 754 double-double.

From d_longdbl.U:

This variable conditionally defines LONG_DOUBLE_STYLE_IEEE_EXTENDED if the long double is the 80-bit IEEE 754 extended precision. Note that despite the extended this is less than the std, since this is an extension of the double precision.

From d_longdbl.U:

This variable conditionally defines LONG_DOUBLE_STYLE_IEEE_STD if the long double is the 128-bit IEEE 754.

From d_longdbl.U:

This variable conditionally defines LONG_DOUBLE_STYLE_VAX if the long double is the 128-bit VAX format H.

From d_longdbl.U:

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

From d_longlong.U:

This variable conditionally defines HAS_LONG_LONG if the long long type is supported.

From d_lrint.U:

This variable conditionally defines the HAS_LRINT symbol, which indicates to the C program that the lrint() routine is available to return the integral value closest to a double (according to the current rounding mode).

From d_lrintl.U:

This variable conditionally defines the HAS_LRINTL symbol, which indicates to the C program that the lrintl() routine is available to return the integral value closest to a long double (according to the current rounding mode).

From d_lround.U:

This variable conditionally defines the HAS_LROUND symbol, which indicates to the C program that the lround() routine is available to return the integral value nearest to x.

From d_lroundl.U:

This variable conditionally defines the HAS_LROUNDL symbol, which indicates to the C program that the lroundl() routine is available to return the integral value nearest to x away from zero.

From 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.

From d_lstat.U:

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

From d_madvise.U:

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

From d_malloc_size.U:

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

From d_malloc_size.U:

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

From d_malloc_size.U:

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

From 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 multibyte character.

From d_mbrlen.U:

This variable conditionally defines the HAS_MBRLEN symbol if the mbrlen() routine is available to be used to get the length of multi-byte character strings.

From d_mbrtowc.U:

This variable conditionally defines the HAS_MBRTOWC symbol if the mbrtowc() routine is available to be used to convert a multi-byte character into a wide character.

From 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.

From 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.

From d_memmem.U:

This variable conditionally defines the HAS_MEMMEM symbol, which indicates to the C program that the memmem() routine is available to return a pointer to the start of the first occurrence of a substring in a memory area (or NULL if not found).

From d_memrchr.U:

This variable conditionally defines the HAS_MEMRCHR symbol, which indicates to the C program that the memrchr() routine is available to return a pointer to the last occurrence of a byte in a memory area (or NULL if not found).

From 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..

From 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.

From d_mkfifo.U:

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

From d_mkostemp.U:

This variable conditionally defines HAS_MKOSTEMP if mkostemp() is available to exclusively create and open a uniquely named (with a suffix) temporary file.

From 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.

From 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.

From d_mktime.U:

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

From d_timefuncs64.U:

This variable conditionally defines the HAS_MKTIME64 symbol, which indicates to the C program that the mktime64 () routine is available.

From d_mmap.U:

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

From d_modfl.U:

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

From d_modfl.U:

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

From d_mprotect.U:

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

From d_msg.U:

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

From 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.

From 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.

From 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.

From 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.

From 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.

From d_msgctl.U:

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

From d_msgget.U:

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

From d_msghdr_s.U:

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

From d_msgrcv.U:

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

From d_msgsnd.U:

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

From d_msync.U:

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

From d_munmap.U:

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

From mallocsrc.U:

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

From d_nan.U:

This variable conditionally defines HAS_NAN if nan() is available to generate NaN.

From d_nanosleep.U:

This variable conditionally defines HAS_NANOSLEEP if nanosleep() is available to sleep with 1E-9 sec accuracy.

From i_ndbm.U:

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

From i_ndbm.U:

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

From d_nearbyint.U:

This variable conditionally defines HAS_NEARBYINT if nearbyint() is available to return the integral value closest to (according to the current rounding mode) to x.

From d_newlocale.U:

This variable conditionally defines the HAS_NEWLOCALE symbol, which indicates to the C program that the newlocale() routine is available to return a new locale object or modify an existing locale object.

From d_nextafter.U:

This variable conditionally defines HAS_NEXTAFTER if nextafter() is available to return the next machine representable double from x in direction y.

From d_nexttoward.U:

This variable conditionally defines HAS_NEXTTOWARD if nexttoward() is available to return the next machine representable long double from x in direction y.

From d_nice.U:

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

From d_nl_langinfo.U:

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

From d_nl_langinfo.U:

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

From d_bitfield.U:

This variable conditionally defines HAS_NON_INT_BITFIELDS which indicates that the C compiler accepts struct bitfields of sizes that aren't int or unsigned int

From perlxv.U:

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

From perlxv.U:

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

From d_off64_t.U:

This symbol will be defined if the C compiler supports off64_t.

From d_pthrattrj.U:

This variable conditionally defines pthread_create_joinable. undef if pthread.h defines PTHREAD_CREATE_JOINABLE.

From 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.

From 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.

From 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.

From d_fsat.U:

This variable conditionally defines the HAS_OPENAT symbol, which indicates the POSIX openat() function is available.

From 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.

From 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.

From disparate_lc_all.U:

This symbol, if defined, indicates that $lc_all_category_positions_init is valid

From disparate_lc_all.U:

This symbol, if defined, indicates that $perl_lc_all_separator is valid

From disparate_lc_all.U:

This symbol, if defined, indicates that the string returned by setlocale(LC_ALL, NULL) uses name=value; pairs to indicate what each category's locale is when they aren't all set to the same locale. When not defined, the platform uses positional notation.

From 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.

From 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.

From 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.

From d_pipe2.U:

This variable conditionally defines the HAS_PIPE2 symbol, which indicates to the C program that the pipe2() routine is available to create an inter-process channel.

From 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.

From 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.

From d_prctl.U:

This variable conditionally defines the HAS_PRCTL symbol, which indicates to the C program that the prctl() routine is available. Note that there are at least two prctl variants: Linux and Irix. While they are somewhat similar, they are incompatible.

From d_prctl.U:

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

From d_attribut.U:

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

From d_procselfexe.U:

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

From d_vfork.U:

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

From d_pthread_atfork.U:

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

From d_pthread_attr_ss.U:

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

From 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.

From d_ptrdiff_t.U:

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

From i_pwd.U:

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

From i_pwd.U:

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

From i_pwd.U:

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

From i_pwd.U:

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

From i_pwd.U:

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

From i_pwd.U:

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

From i_pwd.U:

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

From i_pwd.U:

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

From d_qgcvt.U:

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

From quadtype.U:

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

From d_newlocale.U:

This variable conditionally defines the HAS_QUERYLOCALE symbol, which indicates to the C program that the querylocale() routine is available to return the name of the locale for a category mask.

From d_random_r.U:

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

From d_regcmp.U:

This variable conditionally defines the HAS_RECOMP symbol, which indicates to the C program that the re_comp() routine is available for regular pattern matching (usually on BSD). If so, it is likely that re_exec() exists.

From d_readdir.U:

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

From d_readdir64_r.U:

This variable conditionally defines the HAS_READDIR64_R symbol, which indicates to the C program that the readdir64_r() routine is available.

From d_readdir_r.U:

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

From 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.

From d_readv.U:

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

From d_recvmsg.U:

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

From d_regcmp.U:

This variable conditionally defines the HAS_REGCMP symbol, which indicates to the C program that the regcmp() routine is available for regular pattern matching (usually on System V).

From d_regcmp.U:

This variable conditionally defines the HAS_REGCOMP symbol, which indicates to the C program that the regcomp() routine is available for regular pattern matching (usually on POSIX.2 conforming systems).

From d_remainder.U:

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

From d_remquo.U:

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

From 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.

From d_fsat.U:

This variable conditionally defines the HAS_RENAMEAT symbol, which indicates the POSIX renameat() function is available.

From d_readdir.U:

This variable conditionally defines HAS_REWINDDIR if rewinddir() is available.

From d_rint.U:

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

From d_rmdir.U:

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

From d_round.U:

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

From 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.

From d_scalbn.U:

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

From d_scalbnl.U:

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

From 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.

From 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.

From d_readdir.U:

This variable conditionally defines HAS_SEEKDIR if seekdir() is available.

From d_select.U:

This variable conditionally defines HAS_SELECT if select() is available to select active file descriptors. A <sys/time.h> inclusion may be necessary for the timeout field.

From d_sem.U:

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

From d_semctl.U:

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

From 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.

From d_union_semun.U:

This variable conditionally defines USE_SEMCTL_SEMUN, which indicates that union semun is to be used for semctl IPC_STAT.

From d_semget.U:

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

From d_semop.U:

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

From d_sendmsg.U:

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

From 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.

From d_setenv.U:

This variable conditionally defines the HAS_SETENV symbol, which indicates to the C program that the setenv routine is available.

From 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.

From 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.

From d_setgrent_r.U:

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

From 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.

From d_sethent.U:

This variable conditionally defines HAS_SETHOSTENT if sethostent() is available.

From d_sethostent_r.U:

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

From d_setitimer.U:

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

From 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.

From d_setlocale.U:

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

From d_setlocale.U:

This variable conditionally defines SETLOCALE_ACCEPTS_ANY_LOCALE_NAME if setlocale() accepts any locale name.

From d_setlocale_r.U:

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

From d_setnent.U:

This variable conditionally defines HAS_SETNETENT if setnetent() is available.

From d_setnetent_r.U:

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

From d_setpent.U:

This variable conditionally defines HAS_SETPROTOENT if setprotoent() is available.

From d_setpgid.U:

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

From d_setpgrp.U:

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

From 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.

From d_setprior.U:

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

From d_setproctitle.U:

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

From d_setprotoent_r.U:

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

From 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.

From d_setpwent_r.U:

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

From d_setregid.U:

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

From 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.

From 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.

From d_setreuid.U:

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

From 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.

From 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.

From d_setsent.U:

This variable conditionally defines HAS_SETSERVENT if setservent() is available.

From d_setservent_r.U:

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

From d_setsid.U:

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

From 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.

From d_shm.U:

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

From d_shmat.U:

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

From d_shmat.U:

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

From d_shmctl.U:

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

From d_shmdt.U:

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

From d_shmget.U:

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

From d_sigaction.U:

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

From d_siginfo_si.U:

This variable conditionally defines the HAS_SIGINFO_SI_ADDR symbol, which indicates that the siginfo_t struct has the si_addr member.

From d_siginfo_si.U:

This variable conditionally defines the HAS_SIGINFO_SI_BAND symbol, which indicates that the siginfo_t struct has the si_band member.

From d_siginfo_si.U:

This variable conditionally defines the HAS_SIGINFO_SI_ERRNO symbol, which indicates that the siginfo_t struct has the si_errno member.

From d_siginfo_si.U:

This variable conditionally defines the HAS_SIGINFO_SI_FD symbol, which indicates that the siginfo_t struct has the si_fd member.

From d_siginfo_si.U:

This variable conditionally defines the HAS_SIGINFO_SI_PID symbol, which indicates that the siginfo_t struct has the si_pid member.

From d_siginfo_si.U:

This variable conditionally defines the HAS_SIGINFO_SI_STATUS symbol, which indicates that the siginfo_t struct has the si_status member.

From d_siginfo_si.U:

This variable conditionally defines the HAS_SIGINFO_SI_UID symbol, which indicates that the siginfo_t struct has the si_uid member.

From d_siginfo_si.U:

This variable conditionally defines the HAS_SIGINFO_SI_VALUE symbol, which indicates that the siginfo_t struct has the si_value member.

From d_signbit.U:

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

From d_sigprocmask.U:

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

From 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.

From d_socket.U:

This variable conditionally defines the HAS_SIN6_SCOPE_ID symbol, which indicates that a struct sockaddr_in6 structure has the sin6_scope_id member.

From sitearch.U:

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

From d_snprintf.U:

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

From d_socket.U:

This variable conditionally defines the HAS_SOCKADDR_IN6 symbol, which indicates the availability of a struct sockaddr_in6.

From d_socket.U:

This variable conditionally defines the HAS_SOCKADDR_SA_LEN symbol, which indicates that a struct sockaddr structure has the sa_len member.

From d_socket.U:

This variable conditionally defines the HAS_SOCKADDR_STORAGE symbol, which indicates the availability of a struct sockaddr_storage.

From d_sockatmark.U:

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

From d_sockatmarkproto.U:

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

From d_socket.U:

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

From d_socklen_t.U:

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

From d_socket.U:

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

From 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.

From d_sqrtl.U:

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

From d_srand48_r.U:

This variable conditionally defines the HAS_SRAND48_R symbol, which indicates to the C program that the srand48_r() routine is available.

From d_srandom_r.U:

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

From d_sresgproto.U:

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

From d_sresuproto.U:

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

From d_stat.U:

This variable conditionally defines HAS_STAT if stat() is available to get file status.

From d_statblks.U:

This variable conditionally defines USE_STAT_BLOCKS if this system has a stat structure declaring st_blksize and st_blocks.

From 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).

From d_statfs_s.U:

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

From d_static_inline.U:

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

From d_statvfs.U:

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

From d_stdstdio.U:

This variable conditionally defines STDIO_CNT_LVALUE if the FILE_cnt macro can be used as an lvalue.

From d_stdstdio.U:

This variable conditionally defines STDIO_PTR_LVALUE if the FILE_ptr macro can be used as an lvalue.

From 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.

From 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.

From stdio_streams.U:

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

From 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.

From 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.

From d_strcoll.U:

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

From d_strerror_l.U:

This variable conditionally defines the HAS_STRERROR_L symbol, which indicates to the C program that the strerror_l() routine is available to return the error message for a given errno value in a particular locale (identified by a locale_t object).

From d_strerror_r.U:

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

From d_strftime.U:

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

From d_strlcat.U:

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

From d_strlcpy.U:

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

From d_strnlen.U:

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

From 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().

From d_strtod_l.U:

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

From 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.

From d_strtold.U:

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

From d_strtold_l.U:

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

From d_strtoll.U:

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

From d_strtoq.U:

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

From 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.

From d_strtoull.U:

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

From d_strtouq.U:

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

From d_strxfrm.U:

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

From d_strxfrm_l.U:

This variable conditionally defines HAS_STRXFRM_L if strxfrm_l() is available to transform strings.

From d_dosuid.U:

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

From 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.

From d_syscall.U:

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

From d_syscallproto.U:

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

From 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.

From d_strerror.U:

This variable conditionally defines HAS_SYS_ERRNOLIST if sys_errnolist[] is available to translate error numbers to the symbolic name.

From d_strerror.U:

This variable conditionally defines HAS_SYS_ERRLIST if sys_errlist[] is available to translate error numbers to strings.

From d_system.U:

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

From 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.

From 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.

From d_readdir.U:

This variable conditionally defines HAS_TELLDIR if telldir() is available.

From 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.

From d_tgamma.U:

This variable conditionally defines the HAS_TGAMMA symbol, which indicates to the C program that the tgamma() routine is available for the gamma function. See also d_lgamma.

From d_thread_local.U:

This variable conditionally defines the PERL_THREAD_LOCAL symbol. In turn that gives a linkage specification for thread-local storage.

From d_time.U:

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

From d_timegm.U:

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

From d_times.U:

This variable conditionally defines the HAS_TIMES symbol, which indicates that the times() routine exists. The times() routine is normally provided on UNIX systems. You may have to include <sys/times.h>.

From i_time.U:

This variable conditionally defines HAS_TM_TM_GMTOFF, which indicates to the C program that the struct tm has the tm_gmtoff field.

From i_time.U:

This variable conditionally defines HAS_TM_TM_ZONE, which indicates to the C program that the struct tm has the tm_zone field.

From d_tmpnam_r.U:

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

From d_towlower.U:

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

From d_towupper.U:

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

From d_trunc.U:

This variable conditionally defines the HAS_TRUNC symbol, which indicates to the C program that the trunc() routine is available to round doubles towards zero.

From d_truncate.U:

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

From d_truncl.U:

This variable conditionally defines the HAS_TRUNCL symbol, which indicates to the C program that the truncl() routine is available to round long doubles towards zero. If copysignl is also present, we can emulate modfl.

From d_ttyname_r.U:

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

From d_tzname.U:

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

From d_u32align.U:

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

From d_ualarm.U:

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

From 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.

From 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.

From d_union_semun.U:

This variable conditionally defines HAS_UNION_SEMUN if the union semun is defined by including <sys/sem.h>.

From d_fsat.U:

This variable conditionally defines the HAS_UNLINKAT symbol, which indicates the POSIX unlinkat() function isavailable.

From d_unordered.U:

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

From d_unsetenv.U:

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

From d_newlocale.U:

This variable conditionally defines the HAS_USELOCALE symbol, which indicates to the C program that the uselocale() routine is available to set the current locale for the calling thread.

From d_usleep.U:

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

From d_usleepproto.U:

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

From d_ustat.U:

This variable conditionally defines HAS_USTAT if ustat() is available to query file system statistics by dev_t.

From vendorarch.U:

This variable conditionally defined PERL_VENDORARCH.

From vendorbin.U:

This variable conditionally defines PERL_VENDORBIN.

From vendorlib.U:

This variable conditionally defines PERL_VENDORLIB.

From vendorscript.U:

This variable conditionally defines PERL_VENDORSCRIPT.

From d_vfork.U:

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

From d_closedir.U:

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

From 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(...))()".

From 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 descriptors and do a setpgrp().

From d_snprintf.U:

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

From d_wait4.U:

This variable conditionally defines the HAS_WAIT4 symbol, which indicates the wait4() routine is available.

From d_waitpid.U:

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

From d_wcrtomb.U:

This variable conditionally defines the HAS_WCRTOMB symbol if the wcrtomb() routine is available to be used to convert a wide character into a multi-byte character.

From d_wcscmp.U:

This variable conditionally defines the HAS_WCSCMP symbol if the wcscmp() routine is available and can be used to compare wide character strings.

From 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.

From d_wcsxfrm.U:

This variable conditionally defines the HAS_WCSXFRM symbol if the wcsxfrm() routine is available and can be used to compare wide character strings.

From 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.

From d_writev.U:

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

From Guess.U:

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

From Loc.U:

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

From i_db.U:

This variable contains the type of the hash structure element in the <db.h> header file. In older versions of DB, it was int, while in newer ones it is u_int32_t.

From i_db.U:

This variable contains the type of the prefix structure element in the <db.h> header file. In older versions of DB, it was int, while in newer ones it is size_t.

From i_db.U:

This variable contains the major version number of Berkeley DB found in the <db.h> header file.

From i_db.U:

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

From i_db.U:

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

From defaultincdot.U:

When defined, remove the legacy . from @INC

From 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.

From dlext.U:

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

From dlsrc.U:

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

From infnan.U:

This variable contains comma-separated list of hexadecimal bytes for the double precision infinity.

From longdblfio.U:

This variable, if defined, encodes the type of a double: 1 = IEEE 754 32-bit little endian, 2 = IEEE 754 32-bit big endian, 3 = IEEE 754 64-bit little endian, 4 = IEEE 754 64-bit big endian, 5 = IEEE 754 128-bit little endian, 6 = IEEE 754 128-bit big endian, 7 = IEEE 754 64-bit mixed endian le-be, 8 = IEEE 754 64-bit mixed endian be-le, 9 = VAX 32bit little endian F float format 10 = VAX 64bit little endian D float format 11 = VAX 64bit little endian G float format 12 = IBM 32bit format 13 = IBM 64bit format 14 = Cray 64bit format -1 = unknown format.

From mantbits.U:

This symbol, if defined, tells how many mantissa bits there are in double precision floating point format. Note that this is usually DBL_MANT_DIG minus one, since with the standard IEEE 754 formats DBL_MANT_DIG includes the implicit bit which doesn't really exist.

From infnan.U:

This variable contains comma-separated list of hexadecimal bytes for the double precision not-a-number.

From doublesize.U:

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

From randfunc.U:

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

From d_drand48_r.U:

This variable encodes the prototype of drand48_r. It is zero if d_drand48_r is undef, and one of the REENTRANT_PROTO_T_ABC macros of reentr.h if d_drand48_r is defined.

From usedtrace.U:

This variable holds the location of the dtrace executable.

From dtraceobject.U:

Whether we need to build an object file with the dtrace tool.

From dtraceobject.U:

Whether dtrace accepts -xnolibs. If available we call dtrace -h and dtrace -G with -xnolibs to allow dtrace to run in a jail on FreeBSD.

From Extensions.U:

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

From perlxv.U:

This variable is the size of an I16 in bytes.

From perlxv.U:

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

From perlx32f.U:

This variable contains the format string used for printing a Perl I32 as a signed decimal integer.

From perlxv.U:

This variable is the size of an I32 in bytes.

From perlxv.U:

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

From perlxv.U:

This variable is the size of an I64 in bytes.

From perlxv.U:

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

From perlxv.U:

This variable is the size of an I8 in bytes.

From perlxv.U:

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

From i_arpainet.U:

This variable conditionally defines the I_ARPA_INET symbol, and indicates whether a C program should include <arpa/inet.h>.

From i_bfd.U:

This variable conditionally defines the I_BFD symbol, and indicates whether a C program can include <bfd.h>.

From i_sysioctl.U:

This variable conditionally defines the I_SYS_BSDIOCTL symbol, which indicates to the C program that <sys/bsdioctl.h> exists and should be included.

From i_crypt.U:

This variable conditionally defines the I_CRYPT symbol, and indicates whether a C program should include <crypt.h>.

From i_db.U:

This variable conditionally defines the I_DB symbol, and indicates whether a C program may include Berkeley's DB include file <db.h>.

From i_dbm.U:

This variable conditionally defines the I_DBM symbol, which indicates to the C program that <dbm.h> exists and should be included.

From i_dirent.U:

This variable conditionally defines I_DIRENT, which indicates to the C program that it should include <dirent.h>.

From i_dlfcn.U:

This variable conditionally defines the I_DLFCN symbol, which indicates to the C program that <dlfcn.h> exists and should be included.

From i_execinfo.U:

This variable conditionally defines the I_EXECINFO symbol, and indicates whether a C program may include <execinfo.h>, for backtrace() support.

From i_fcntl.U:

This variable controls the value of I_FCNTL (which tells the C program to include <fcntl.h>).

From i_fenv.U:

This variable conditionally defines the I_FENV symbol, which indicates to the C program that <fenv.h> exists and should be included.

From i_fp.U:

This variable conditionally defines the I_FP symbol, and indicates whether a C program should include <fp.h>.

From i_fp_class.U:

This variable conditionally defines the I_FP_CLASS symbol, and indicates whether a C program should include <fp_class.h>.

From i_gdbm.U:

This variable conditionally defines the I_GDBM symbol, which indicates to the C program that <gdbm.h> exists and should be included.

From i_ndbm.U:

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

From i_ndbm.U:

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

From i_grp.U:

This variable conditionally defines the I_GRP symbol, and indicates whether a C program should include <grp.h>.

From i_ieeefp.U:

This variable conditionally defines the I_IEEEFP symbol, and indicates whether a C program should include <ieeefp.h>.

From i_inttypes.U:

This variable conditionally defines the I_INTTYPES symbol, and indicates whether a C program should include <inttypes.h>.

From i_langinfo.U:

This variable conditionally defines the I_LANGINFO symbol, and indicates whether a C program should include <langinfo.h>.

From i_libutil.U:

This variable conditionally defines the I_LIBUTIL symbol, and indicates whether a C program should include <libutil.h>.

From i_locale.U:

This variable conditionally defines the I_LOCALE symbol, and indicates whether a C program should include <locale.h>.

From i_machcthr.U:

This variable conditionally defines the I_MACH_CTHREADS symbol, and indicates whether a C program should include <mach/cthreads.h>.

From i_malloc.U:

This variable conditionally defines the I_MALLOC symbol, and indicates whether a C program should include <malloc.h>.

From i_mallocmalloc.U:

This variable conditionally defines the I_MALLOCMALLOC symbol, and indicates whether a C program should include <malloc/malloc.h>.

From i_mntent.U:

This variable conditionally defines the I_MNTENT symbol, and indicates whether a C program should include <mntent.h>.

From i_ndbm.U:

This variable conditionally defines the I_NDBM symbol, which indicates to the C program that <ndbm.h> exists and should be included.

From i_netdb.U:

This variable conditionally defines the I_NETDB symbol, and indicates whether a C program should include <netdb.h>.

From i_neterrno.U:

This variable conditionally defines the I_NET_ERRNO symbol, which indicates to the C program that <net/errno.h> exists and should be included.

From i_netinettcp.U:

This variable conditionally defines the I_NETINET_TCP symbol, and indicates whether a C program should include <netinet/tcp.h>.

From i_niin.U:

This variable conditionally defines I_NETINET_IN, which indicates to the C program that it should include <netinet/in.h>. Otherwise, you may try <sys/in.h>.

From i_poll.U:

This variable conditionally defines the I_POLL symbol, and indicates whether a C program should include <poll.h>.

From i_prot.U:

This variable conditionally defines the I_PROT symbol, and indicates whether a C program should include <prot.h>.

From i_pthread.U:

This variable conditionally defines the I_PTHREAD symbol, and indicates whether a C program should include <pthread.h>.

From i_pwd.U:

This variable conditionally defines I_PWD, which indicates to the C program that it should include <pwd.h>.

From i_quadmath.U:

This variable conditionally defines I_QUADMATH, which indicates to the C program that it should include <quadmath.h>.

From i_dbm.U:

This variable conditionally defines the I_RPCSVC_DBM symbol, which indicates to the C program that <rpcsvc/dbm.h> exists and should be included. Some System V systems might need this instead of <dbm.h>.

From i_termio.U:

This variable conditionally defines the I_SGTTY symbol, which indicates to the C program that it should include <sgtty.h> rather than <termio.h>.

From i_shadow.U:

This variable conditionally defines the I_SHADOW symbol, and indicates whether a C program should include <shadow.h>.

From i_socks.U:

This variable conditionally defines the I_SOCKS symbol, and indicates whether a C program should include <socks.h>.

From i_stdbool.U:

This variable conditionally defines the I_STDBOOL symbol, which indicates to the C program that <stdbool.h> exists and should be included.

From i_stdint.U:

This variable conditionally defines the I_STDINT symbol, which indicates to the C program that <stdint.h> exists and should be included.

From i_stdlib.U:

This variable unconditionally defines the I_STDLIB symbol.

From i_sunmath.U:

This variable conditionally defines the I_SUNMATH symbol, and indicates whether a C program should include <sunmath.h>.

From i_sysaccess.U:

This variable conditionally defines the I_SYS_ACCESS symbol, and indicates whether a C program should include <sys/access.h>.

From i_sysdir.U:

This variable conditionally defines the I_SYS_DIR symbol, and indicates whether a C program should include <sys/dir.h>.

From i_sysfile.U:

This variable conditionally defines the I_SYS_FILE symbol, and indicates whether a C program should include <sys/file.h> to get R_OK and friends.

From i_sysioctl.U:

This variable conditionally defines the I_SYS_FILIO symbol, which indicates to the C program that <sys/filio.h> exists and should be included in preference to <sys/ioctl.h>.

From i_niin.U:

This variable conditionally defines I_SYS_IN, which indicates to the C program that it should include <sys/in.h> instead of <netinet/in.h>.

From i_sysioctl.U:

This variable conditionally defines the I_SYS_IOCTL symbol, which indicates to the C program that <sys/ioctl.h> exists and should be included.

From i_syslog.U:

This variable conditionally defines the I_SYSLOG symbol, and indicates whether a C program should include <syslog.h>.

From i_sysmman.U:

This variable conditionally defines the I_SYS_MMAN symbol, and indicates whether a C program should include <sys/mman.h>.

From i_sysmode.U:

This variable conditionally defines the I_SYSMODE symbol, and indicates whether a C program should include <sys/mode.h>.

From i_sysmount.U:

This variable conditionally defines the I_SYSMOUNT symbol, and indicates whether a C program should include <sys/mount.h>.

From i_sysndir.U:

This variable conditionally defines the I_SYS_NDIR symbol, and indicates whether a C program should include <sys/ndir.h>.

From i_sysparam.U:

This variable conditionally defines the I_SYS_PARAM symbol, and indicates whether a C program should include <sys/param.h>.

From i_syspoll.U:

This variable conditionally defines the I_SYS_POLL symbol, which indicates to the C program that it should include <sys/poll.h>.

From i_sysresrc.U:

This variable conditionally defines the I_SYS_RESOURCE symbol, and indicates whether a C program should include <sys/resource.h>.

From i_syssecrt.U:

This variable conditionally defines the I_SYS_SECURITY symbol, and indicates whether a C program should include <sys/security.h>.

From i_sysselct.U:

This variable conditionally defines I_SYS_SELECT, which indicates to the C program that it should include <sys/select.h> in order to get the definition of struct timeval.

From i_sysioctl.U:

This variable conditionally defines I_SYS_SOCKIO to indicate to the C program that socket ioctl codes may be found in <sys/sockio.h> instead of <sys/ioctl.h>.

From i_sysstat.U:

This variable conditionally defines the I_SYS_STAT symbol, and indicates whether a C program should include <sys/stat.h>.

From i_sysstatfs.U:

This variable conditionally defines the I_SYSSTATFS symbol, and indicates whether a C program should include <sys/statfs.h>.

From i_sysstatvfs.U:

This variable conditionally defines the I_SYSSTATVFS symbol, and indicates whether a C program should include <sys/statvfs.h>.

From i_syssyscall.U:

This variable conditionally defines the I_SYS_SYSCALL symbol, and indicates whether a C program should include <sys/syscall.h>.

From i_time.U:

This variable conditionally defines I_SYS_TIME, which indicates to the C program that it should include <sys/time.h>.

From i_time.U:

This variable conditionally defines I_SYS_TIME_KERNEL, which indicates to the C program that it should include <sys/time.h> with KERNEL defined.

From i_systimes.U:

This variable conditionally defines the I_SYS_TIMES symbol, and indicates whether a C program should include <sys/times.h>.

From i_systypes.U:

This variable conditionally defines the I_SYS_TYPES symbol, and indicates whether a C program should include <sys/types.h>.

From i_sysuio.U:

This variable conditionally defines the I_SYSUIO symbol, and indicates whether a C program should include <sys/uio.h>.

From i_sysun.U:

This variable conditionally defines I_SYS_UN, which indicates to the C program that it should include <sys/un.h> to get UNIX domain socket definitions.

From i_sysutsname.U:

This variable conditionally defines the I_SYSUTSNAME symbol, and indicates whether a C program should include <sys/utsname.h>.

From i_sysvfs.U:

This variable conditionally defines the I_SYSVFS symbol, and indicates whether a C program should include <sys/vfs.h>.

From i_syswait.U:

This variable conditionally defines I_SYS_WAIT, which indicates to the C program that it should include <sys/wait.h>.

From i_termio.U:

This variable conditionally defines the I_TERMIO symbol, which indicates to the C program that it should include <termio.h> rather than <sgtty.h>.

From i_termio.U:

This variable conditionally defines the I_TERMIOS symbol, which indicates to the C program that the POSIX <termios.h> file is to be included.

From i_time.U:

This variable unconditionally defines I_TIME, which indicates to the C program that it should include <time.h>.

From i_unistd.U:

This variable conditionally defines the I_UNISTD symbol, and indicates whether a C program should include <unistd.h>.

From i_ustat.U:

This variable conditionally defines the I_USTAT symbol, and indicates whether a C program should include <ustat.h>.

From i_utime.U:

This variable conditionally defines the I_UTIME symbol, and indicates whether a C program should include <utime.h>.

From i_vfork.U:

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

From i_wchar.U:

This variable conditionally defines the I_WCHAR symbol, that indicates whether a C program may include <wchar.h>.

From i_wctype.U:

This variable conditionally defines the I_WCTYPE symbol, that indicates whether a C program may include <wctype.h>.

From d_newlocale.U:

This symbol, if defined, indicates to the C program that the header xlocale.h is available. See also xlocale_needed.

From libs.U:

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

From 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.

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

From 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.

From usrinc.U:

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

From libpth.U:

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

From Loc.U:

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

From bin.U:

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

From archlib.U:

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

From bin.U:

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

From html1dir.U:

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

From html3dir.U:

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

From man1dir.U:

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

From man3dir.U:

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

From installprefix.U:

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

From installprefix.U:

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

From privlib.U:

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

From scriptdir.U:

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

From sitearch.U:

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

From sitebin.U:

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

From sitehtml1dir.U:

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

From sitehtml3dir.U:

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

From sitelib.U:

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

From siteman1dir.U:

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

From siteman3dir.U:

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

From sitescript.U:

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

From installstyle.U:

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

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

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

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

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

From instubperl.U:

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

From vendorarch.U:

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

From vendorbin.U:

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

From vendorhtml1dir.U:

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

From vendorhtml3dir.U:

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

From vendorlib.U:

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

From vendorman1dir.U:

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

From vendorman3dir.U:

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

From vendorscript.U:

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

From intsize.U:

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

From issymlink.U:

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

From perlxvf.U:

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

From perlxv.U:

This variable is the size of an IV in bytes.

From perlxv.U:

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