compiler flags

I've been searching for some list of all compiler flags for various architectures and operating systems. Its very frustrating to get stuck at that. Considering my little knowledge, it takes me quite a fair bit of time to find what I need.

Thanks to Brian Hook, who seems to have collected a great list compiler defines for various architectures and operating systems. Here is the actual link.

GNU GCC/G++:
- __GNUC__: GNU C version
- __GNUG__: GNU C++ compiler
- __sun__ : on Sun platforms
- __svr4__: on Solaris and other SysV R4 platforms
- __mips__: on MIPS processor platforms
- __sparc_v9__: on Sparc 64-bit CPUs
- __sparcv9: 64-bit Solaris
- __MIPSEL__: mips processor, compiled for little endian
- __MIPSEB__: mips processor, compiled for big endian
- _R5900: MIPS/Sony/Toshiba R5900 (PS2)
- mc68000: 68K
- m68000: 68K
- m68k: 68K
- __palmos__: PalmOS

Intel C/C++ Compiler:
- __ECC : compiler version, IA64 only
- __EDG__
- __ELF__
- __GXX_ABI_VERSION
- __i386 : IA-32 only
- __i386__ : IA-32 only
- i386 : IA-32 only
- __ia64 : IA-64 only
- __ia64__ : IA-64 only
- ia64 : IA-64 only
- __ICC : IA-32 only
- __INTEL_COMPILER : IA-32 or IA-64, newer versions only

Apple's C/C++ Compiler for OS X:
- __APPLE_CC__
- __APPLE__
- __BIG_ENDIAN__
- __APPLE__
- __ppc__
- __MACH__

DJGPP:
- __MSDOS__
- __unix__
- __unix
- __GNUC__
- __GO32
- DJGPP
- __i386, __i386, i386

Cray's C compiler:
- _ADDR64: if 64-bit pointers
- _UNICOS:
- __unix:

SGI's CC compiler predefines the following (and more) with -ansi:
- __sgi
- __unix
- __host_mips
- _SYSTYPE_SVR4
- __mips
- _MIPSEB
- anyone know if there is a predefined symbol for the compiler?!

MinGW:
- as GnuC but also defines _WIN32, __WIN32, WIN32, _X86_, __i386, __i386__, and several others
- __MINGW32__

Cygwin:
- as Gnu C, but also
- __unix__
- __CYGWIN32__

Microsoft Visual Studio predefines the following:
- _MSC_VER
- _WIN32: on Win32
- _M_IX6 (on x86 systems)
- _M_X64: on x86-64 systems
- _M_ALPHA (on DEC AXP systems)
- _SH3: WinCE, Hitachi SH-3
- _MIPS: WinCE, MIPS
- _ARM: WinCE, ARM

Sun's C Compiler:
- sun and _sun
- unix and _unix
- sparc and _sparc (SPARC systems only)
- i386 and _i386 (x86 systems only)
- __SVR4 (Solaris only)
- __sparcv9: 64-bit solaris
- __SUNPRO_C
- _LP64: defined in 64-bit LP64 mode, but only if is included

Borland C/C++ predefines the following:
- __BORLANDC__:

DEC/Compaq C/C++ on Alpha:
- __alpha
- __arch64__
- __unix__ (on Tru64 Unix)
- __osf__
- __DECC
- __DECCXX (C++ compilation)
- __DECC_VER
- __DECCXX_VER

IBM's AIX compiler:
- __64BIT__ if 64-bit mode
- _AIX
- __IBMC__: C compiler version
- __IBMCPP__: C++ compiler version
- _LONG_LONG: compiler allows long long

Watcom:
- __WATCOMC__
- __DOS__ : if targeting DOS
- __386__ : if 32-bit support
- __WIN32__ : if targetin 32-bit Windows

HP-UX C/C++ Compiler:
- __hpux
- __unix
- __hppa (on PA-RISC)
- __LP64__: if compiled in 64-bit mode

Metrowerks:
- __MWERKS__
- __powerpc__
- _powerc
- __MC68K__
- macintosh when compiling for MacOS
- __INTEL__ for x86 targets
- __POWERPC__