Here are some of the cpp macros used, together with some short explanation
of their use. Feel free to add more macros and more categories.
+Most of these are from config.in, so it's probably better to put the
+explanations in that file. Ideally, everything would be defined and
+documented in config.in, and this file would not be necessary.
+
** Distinguishing OSes **
+AIX
+_AIX
+BSD4_2
+BSD_SYSTEM
CYGWIN Compiling the Cygwin port.
__CYGWIN__ Ditto
+GNU_LINUX
+HPUX
+IRIX6_5
MSDOS Compiling the MS-DOS port.
__MSDOS__ Ditto.
-__DJGPP__ Major version number of the DJGPP library for the DOS port.
-__DJGPP_MINOR__ Minor version number of the DJGPP library.
-__GO32__ Compiling the DOS port with DJGPP v1.x (obsolete).
+__DJGPP_MINOR__ Minor version number of the DJGPP library; used only in msdos.c and dosfns.c.
DOS_NT Compiling for either the MS-DOS or native MS-Windows port.
WINDOWSNT Compiling the native MS-Windows (W32) port.
__MINGW32__ Compiling the W32 port with the MinGW port of GCC.
_MSC_VER Compiling the W32 port with the Microsoft C compiler.
DARWIN_OS Compiling on Mac OS X or pure Darwin (and using s/darwin.h).
+SOLARIS2
+USG
+USG5
+USG5_4
** Distinguishing GUIs **
NS_IMPL_COCOA Compile support for Cocoa (Apple) implementation of NS GUI API.
HAVE_X11 Compile support for the X11 GUI.
HAVE_X_WINDOWS Compile support for X Window system
-X11 ?? Makefile.in suggests it's equivalent to HAVE_X11
+ (It looks like, nowadays, if HAVE_X11 is set, HAVE_X_WINDOWS must
+ be, and vice versa. At least, this is true for configure, and
+ msdos; not sure about nt.)
USE_LUCID Use the Lucid toolkit for menus&scrollbars. Requires HAVE_X11.
USE_MOTIF Use the Motif toolkit for menus&scrollbars. Requires HAVE_X11.
USE_GTK Use the Gtk toolkit for menus&scrollbars. Requires HAVE_X11.
REL_ALLOC Compile in the relocatable memory allocator ralloc.c.
SYSTEM_MALLOC Use the system library's malloc.
-subprocesses System can use subprocesses (for M-x shell for example). Defined by default, only MSDOS undefines it.
-USE_LISP_UNION_TYPE Define it in lisp.h to make Lisp_Object be a union type instead of the default int.
+subprocesses System can use subprocesses (for M-x shell for example).
+ Defined by default, only MSDOS undefines it.
+DEBUG_LISP_OBJECT_TYPE Define it in lisp.h enable compile time checks
+ on Lisp_Object use.
-** System specific macros, decribed in detail in src/s/template.h
-BSTRING
-CLASH_DETECTION
-COFF
+** System specific macros
FIRST_PTY_LETTER
HAVE_PTYS
-HAVE_TERMIO
-HAVE_TERMIOS
INTERRUPT_INPUT
-MAIL_USE_FLOCK
NARROWPROTO
-NOMULTIPLEJOBS
SEPCHAR
-SIGTYPE
SYSTEM_TYPE
-USE_MMAP_FOR_BUFFERS
-
-** Machine specific macros, decribed in detail in src/m/template.h
-CANNOT_DUMP
-EXPLICIT_SIGN_EXTEND
-LOAD_AVE_CVT
-LOAD_AVE_TYPE
-NO_ARG_ARRAY
-NO_REMAP
-VIRT_ADDR_VARIES
-WORDS_BIG_ENDIAN
-
-** Not used anymore by any port, can be cleaned up
-NO_SOCK_SIGIO
** Misc macros
-USER_FULL_NAME If defined, overrides the default pw->pw_gecos for getting at the full user name. Only MSDOS overrides the default.
+USER_FULL_NAME If defined, overrides the default pw->pw_gecos for
+getting at the full user name. Only MSDOS overrides the default.
-** Replace, the definition is trivial: SWITCH_ENUM_CAST
+** Miscellaneous defines. Some of these might not be used in the code
+anymore, so they can be removed.
-** Defines from src/m/*.h and src/s/*.h. Some of these might not be used in the code anymore, so they can be removed. The HAVE_* definitions are probably handled by autoconf, so it might be possible to just remove them from src/[sm]/*.h.
-
-
-AIX
AMPERSAND_FULL_NAME
-BCOPY_DOWNWARD_SAFE
-BCOPY_UPWARD_SAFE
-BITS_PER_EMACS_INT
-BITS_PER_LONG
BROKEN_DATAGRAM_SOCKETS
BROKEN_FIONREAD
BROKEN_GET_CURRENT_DIR_NAME
BROKEN_SIGIO
BROKEN_SIGPOLL
BROKEN_SIGPTY
-BSD4_2
-BSD4_3
-BSD_PGRPS
-BSD_SYSTEM
CLASH_DETECTION
-COFF_BSD_SYMBOLS
-CRT0_DUMMIES
-C_DEBUG_SWITCH
-C_SWITCH_MACHINE
-C_SWITCH_SYSTEM
-C_SWITCH_SYSTEM_TEMACS
-C_SWITCH_X_SYSTEM
DATA_SEG_BITS
DATA_START
DBL_MIN_REPLACEMENT
-DECLARE_GETPWUID_WITH_UID_T
DEFAULT_SOUND_DEVICE
DEVICE_SEP
DIRECTORY_SEP
EMACS_CONFIG_OPTIONS
EMACS_INT
EMACS_UINT
-END_FILES_1
-FILE_SYSTEM_CASE
FLOAT_CHECK_DOMAIN
-FSCALE
-GAP_USE_BCOPY
GC_LISP_OBJECT_ALIGNMENT
GC_MARK_SECONDARY_STACK
GC_MARK_STACK
GC_SETJMP_WORKS
GMALLOC_INHIBIT_VALLOC
GNU_LIBRARY_PENDING_OUTPUT_COUNT
-GNU_LINUX
GNU_MALLOC
HAVE_AIX_SMT_EXP
-HAVE_ALLOCA
-HAVE_BCMP
-HAVE_BCOPY
HAVE_CBRT
HAVE_CLOSEDIR
-HAVE_CRTIN
HAVE_DUP2
HAVE_EUIDACCESS
HAVE_FMOD
HAVE_FPATHCONF
HAVE_FREXP
HAVE_FSYNC
-HAVE_FTIME
HAVE_GETCWD
-HAVE_GETDOMAINNAME
HAVE_GETHOSTNAME
HAVE_GETLOADAVG
HAVE_GETPAGESIZE
HAVE_GETTIMEOFDAY
HAVE_GETWD
HAVE_H_ERRNO
-HAVE_INDEX
HAVE_INET_SOCKETS
HAVE_INVERSE_HYPERBOLIC
-HAVE_LIB64_DIR
HAVE_LIBKSTAT
-HAVE_LIBNCURSES
-HAVE_LIBPTHREADS
-HAVE_LIBXMU
HAVE_LIMITS_H
HAVE_LINUX_VERSION_H
HAVE_LOGB
HAVE_LONG_FILE_NAMES
HAVE_LRAND48
HAVE_MENUS
-HAVE_MKDIR
HAVE_MKTIME
HAVE_MOUSE
-HAVE_PERROR
HAVE_PSTAT_GETDYNAMIC
HAVE_PWD_H
HAVE_RANDOM
-HAVE_RENAME
HAVE_RES_INIT
-HAVE_RINDEX
HAVE_RINT
-HAVE_RMDIR
HAVE_SELECT
HAVE_SETLOCALE
HAVE_SETPGID
HAVE_SOCKETS
HAVE_SOUND
HAVE_STDLIB_H
-HAVE_STRERROR
HAVE_STRFTIME
HAVE_STRING_H
HAVE_STRUCT_UTIMBUF
-HAVE_SYSINFO
-HAVE_SYSV_SIGPAUSE
HAVE_SYS_SELECT_H
HAVE_SYS_SYSTEMINFO_H
HAVE_SYS_TIMEB_H
HAVE_SYS_TIME_H
HAVE_TCATTR
-HAVE_TERMIOS_H
-HAVE_TEXT_START
-HAVE_TIMEVAL
HAVE_TM_ZONE
HAVE_TZSET
HAVE_UNISTD_H
-HAVE_UTIMES
HAVE_UTIME_H
-HAVE_VOLATILE
HAVE_WINDOW_SYSTEM
HAVE_WORKING_VFORK
HAVE_XRMSETDATABASE
-HPUX
-IBMR2AIX
-INHIBIT_X11R6_XIM
INTERNAL_TERMINAL
IS_ANY_SEP
IS_DIRECTORY_SEP
-KERNEL_FILE
-LDAV_SYMBOL
-LD_SWITCH_MACHINE
-LD_SWITCH_MACHINE_TEMACS
-LD_SWITCH_SYSTEM
-LD_SWITCH_SYSTEM_TEMACS
-LD_SWITCH_SYSTEM_tmp
-LD_SWITCH_X_DEFAULT
-LIBS_DEBUG
-LIBS_MACHINE
-LIBS_SYSTEM
-LIBS_TERMCAP
-LIBX11_SYSTEM
-LIBXMU
-LIB_GCC
-LIB_MATH
-LIB_MOTIF
-LIB_STANDARD
-LINKER
LINUX_VERSION_CODE
-LISP_FLOAT_TYPE
-LNOFLSH
LOCALTIME_CACHE
+MAIL_USE_FLOCK
MAIL_USE_LOCKF
MAIL_USE_POP
MAIL_USE_SYSTEM_LOCK
MAXPATHLEN
-MIN_PTY_KERNEL_VERSION -- only used on Mac
MODE_LINE_BINARY_TEXT
MUST_UNDEF__STDC__
-NEED_BSDTTY
-NEED_ERRNO
-NEED_LIBW
-NEED_UNISTD_H
NLIST_STRUCT
-NOT_C_CODE
-NOT_USING_MOTIF
NO_ABORT
-NO_DIR_LIBRARY
NO_EDITRES
NO_MATHERR
-NO_SHARED_LIBS
NO_TERMIO
NSIG
NSIG_MINIMUM
-NULL
NULL_DEVICE
ORDINARY_LINK
-OTHER_FILES
O_APPEND
-O_BINARY
-O_CREAT
-O_EXCL
O_RDONLY
O_RDWR
-O_TEXT
-O_TRUNC
-O_WRONLY
PAGESIZE
PENDING_OUTPUT_COUNT
-POSIX
-POSIX_SIGNALS
PREFER_VSUSP
PTY_ITERATION
PTY_NAME_SPRINTF
PURESIZE
RUN_TIME_REMAP
SA_RESTART
-SECTION_ALIGNMENT -- was only used by s/lynxos.h, maybe all code depending on it can be removed.
SEGMENT_MASK
SETPGRP_RELEASES_CTTY
SETUP_SLAVE_PTY
SIGPIPE
SIGQUIT
SIGTRAP
-SIGTYPE
-SOLARIS2
-START_FILES
-START_FILES_1
STDC_HEADERS
-SYMS_SYSTEM
SYSTEM_PURESIZE_EXTRA
SYSTEM_MALLOC
SYSV_SYSTEM_DIR
-Srandom
TAB3
TABDLY
TERM
-TERMINFO
-TEXT_START
-THIS_IS_CONFIGURE
-THIS_IS_MAKEFILE
TIME_WITH_SYS_TIME
TIOCSIGSEND
TM_IN_SYS_TIME
ULIMIT_BREAK_VALUE
-UNEXEC
UNIX98_PTYS
USE_CRT_DLL
-USE_MAC_IMAGE_IO
USE_TOOLKIT_SCROLL_BARS
-USG
-USG5
-USG5_4
USG_SUBTTY_WORKS
VALBITS
-WORDS_BIG_ENDIAN
-WRETCODE
-XINT
XOS_NEEDS_TIME_H
-XPNTR
-XSET
-XUINT
-_AIX
-_ARCH_PPC64
-_CALLBACK_
_FILE_OFFSET_BITS
_LP64
_MALLOC_INTERNAL
_VARARGS_
_WINSOCKAPI_
_WINSOCK_H
-__ELF__
-__FreeBSD__
-__FreeBSD_version
-__GNUC__
-__GNU_LIBRARY__
-__GNUC_MINOR__
-__NetBSD__
-__OpenBSD__
-__STDC__
-__arch64__
-__cplusplus
-__hpux
-__ia64__
-__linux__
-__mc68000__
-__mips__
_longjmp
_setjmp
_start
abort
access
alloca
-bcmp
-bcopy
brk
-bzero
calloc
chdir
chmod
chown
close
-const
creat
ctime
dup
getpid
getuid
gmtime
-i386
index
-init_process
isatty
kill
link
localtime
logb
lseek
-m68k
malloc
mkdir
mktemp
spawnve
srandom
strdup
-strerror
stricmp
strnicmp
strupr
wait
write
xfree
-
-# arch-tag: bc80061a-1168-4911-9766-46aaf2640250