35. Predefined MACROS from compiler、HardWare、OS
《Calling conventions for different C++ compilers and operating systems》
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Most C++ compilers have a predefined macro containing the version number of the
compiler. Programmers can use preprocessing directives to check for the existence of these
macros in order to detect which compiler the program is compiled on and thereby fix
problems with incompatible compilers.
Table 1. Compiler version predefined macros
Compiler | Predefined macro
Borland | __BORLANDC__
Codeplay VectorC | __VECTORC__
Digital Mars | __DMC__
Gnu | __GNUC__
Intel | __INTEL_COMPILER
Microsoft | _MSC_VER
Pathscale | __PATHSCALE__
Symantec | __SYMANTECC__
Watcom | __WATCOMC__Unfortunately, not all compilers have well - documented macros telling which hardware
platform and operating system they are compiling for.The following macros may or may not
be defined :
Table 2. Hardware platform predefined macros
platform | Predefined macro
x86 | _M_IX86 __INTEL__ __i386__
x86-64 | _M_X64 __x86_64__ __amd64
IA64 | __IA64__
DEC Alpha | __ALPHA__
Motorola Power PC | __POWERPC__
Any little endian | __LITTLE_ENDIAN__
Any big endian | __BIG_ENDIAN__Table 3. Operating system predefined macros
Operating system | Predefined macro
DOS 16 bit | __MSDOS__ _MSDOS
Windows 16 bit | _WIN16
Windows 32 bit | _WIN32 __WINDOWS__
Windows 64 bit | _WIN64 _WIN32
Linux 32 bit | __unix__ __linux__
Linux 64 bit | __unix__ __linux__ __LP64__ __amd64
BSD | __unix__ __BSD__ __FREEBSD__
Mac OS | __APPLE__ __DARWIN__ __MACH__
OS / 2 | __OS2__
