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Predefined Preprocessor Identifiers

Both the ANSI-specific and Microsoft-specific predefined identifiers are described in the following lists. If a predefined identifier has two forms, one with and one without an underscore, the command-line driver defines both if you specify the /Ze - Enable Language Extensions option. It defines only the leading underscore form if you specify the /Za - Disable Language Extensions option to compile for ANSI compatibility.

The following table shows the predefined identifiers supported by the compiler.

Identifier Description
_CHAR_UNSIGNED Default char type is unsigned. Defined when /J - Change Default char Type is specified. Microsoft specific.
__cplusplus Identifies a C++ program.
__DATE__ The compilation date of the current source file. The date is a string literal of the form "Mmm dd yyyy". The month nameMmmis the same as for dates generated by the library function asctime declared in Time.h. ANSI-specific.
__FILE__ The name of the current source file __FILE__ expands to a string surrounded by double quotation marks.
__LINE__ The line number in the current source file. The line number is a decimal integer constant. It can be altered with a #line directive. ANSI-specific.
_MSC_VER Defines the compiler version in the form: "ddd". Defined as 1200 for Microsoft C/C++.
_MSDOS Identifies target operating system as MS-DOS. Microsoft-specific.
_M_ARM Defined as 4 for ARM.
_M_ARMT Defined as 4 for Thumb.
__STDC__ Indicates full conformance with the ANSI C standard. Defined as the integer constant 1 only if the /Za command-line option is given; otherwise is undefined. ANSI-specific.
__TIME__ The most recent compilation time of the current source file. The time is a string literal of the form "hh:mm:ss". ANSI-specific.
__TIMESTAMP__ The date and time of the last modification of the source file, expressed as a string literal in the form: "Ddd Mmm Date hh:mm:ss yyyy" where Ddd is the abbreviated day of the week such as Wed and Date is an integer from 1 to 31. Microsoft-specific.

See Also

/J - Change Default char Type | /Za - Disable Language Extensions | /Ze - Enable Language Extensions

 Last updated on Thursday, April 08, 2004

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