3.1 Predefined Macros

In addition to the five predefined macros specified for ANSI C

(__DATE__, __FILE__, __LINE__, __STDC__, and __TIME__), the following macros are predefined in CLAXP:

Identifier

Function

__Alpha_AXP	Always defined. Identifies the target architecture as Digital's Alpha AXP architecture.
	NOTE The identifiers __alpha or __ALPHA are also defined for this purpose for compatibility with the identifiers used in other Digital operating environments. However, __Alpha_ AXP is preferred where suitable.
_ALPHA_	Always defined. Identifies the target architecture for use in the Windows NT header files.
_M_ALPHA	Always defined. Matches _M_MRX000 and _M_X386 on MIPS and Intel platforms.
_WIN32	Always defined, as it is by the other Microsoft_compilers_for_Win32_platforms.

Other macros are defined according to Microsoft conventions:

Identifier

Function

_MSC_VER	Defines the compiler version in the form: ddd. Defined as 800 for version 8.00 of the Microsoft C/C++ language.
_CHAR_UNSIGNED	Defined only when the /J option is given to make char unsigned by default.
__TIMESTAMP__	The date and time of the last modification of the source file.
__cplusplus__	Reserved by Microsoft to assist in portability_between_C_and_C++.