__DATE__

The compilation date of the current source file. The date is a string literal of the form Mmm dd yyyy. The month name Mmm is the same as for dates generated by the library function asctime declared in TIME.H.

__FILE__

The name of the current source file. __FILE__ expands to a string surrounded by double quotation marks. To ensure that the full path to the file is displayed, use /FC (Full Path of Source Code File in Diagnostics).

You can create your own wide string version of __FILE__ as follows:

// compile with: /FC
#include <stdio.h>
#define WIDEN2(x) L ## x
#define WIDEN(x) WIDEN2(x)
#define WC_FILE_ WIDEN(__FILE__)
wchar_t *pwsz = WC_FILE_;
int main() {
  wprintf_s(L"%s\n", WC_FILE_);
}

__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.

__STDC__

Indicates full conformance with the ANSI C standard. Defined as the integer constant 1 only if the /Za compiler option is given and you are not compiling C++ code; otherwise is undefined.

__TIME__

The most recent compilation time of the current source file. The time is a string literal of the form hh:mm:ss.

__TIMESTAMP__

The date and time of the last modification of the current 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 and Date is an integer from 1 to 31.

_ATL_VER

Defines the ATL version.

_CHAR_UNSIGNED

Default char type is unsigned. Defined when /J is specified.

__CLR_VER

Defines the version of the common language runtime used when the application was compiled. The value returned will be in the following format:

Mmmbbbbb

where,

• M is the major version of the runtime

• mm is the minor version of the runtime

• bbbbb is the build number.

// clr_ver.cpp
// compile with: /clr
using namespace System;
int main() {
   Console::WriteLine(__CLR_VER);
}

__cplusplus_cli

Defined when compiling with /clr, /clr:pure, or /clr:safe. Value of __cplusplus_cli is 200406. __cplusplus_cli is in effect throughout the translation unit.

// cplusplus_cli.cpp
// compile with: /clr
#include "stdio.h"
int main() {
   #ifdef __cplusplus_cli
      printf("%d\n", __cplusplus_cli);
   #else
      printf("not defined\n");
   #endif
}

__COUNTER__

Expands to an integer starting with 0 and incrementing by 1 every time it is used in a compiland. __COUNTER__ remembers its state when using precompiled headers. If the last __COUNTER__ value was 4 after building a precompiled header (PCH), it will start with 5 on each PCH use.

__COUNTER__ lets you generate unique variable names. You can use token pasting with a prefix to make a unique name. For example:

// pre_mac_counter.cpp
#include <stdio.h>
#define FUNC2(x,y) x##y
#define FUNC1(x,y) FUNC2(x,y)
#define FUNC(x) FUNC1(x,__COUNTER__)

int FUNC(my_unique_prefix);
int FUNC(my_unique_prefix);

int main() {
   my_unique_prefix0 = 0;
   printf_s("\n%d",my_unique_prefix0);
   my_unique_prefix0++;
   printf_s("\n%d",my_unique_prefix0);
}

__cplusplus

Defined for C++ programs only.

_CPPLIB_VER

Defined if you include any of the C++ Standard Library headers; reports which version of the Dinkumware header files are present.

_CPPRTTI

Defined for code compiled with /GR (Enable Run-Time Type Information).

_CPPUNWIND

Defined for code compiled with /GX (Enable Exception Handling).

_DEBUG

Defined when compiling with /LDd, /MDd, and /MTd.

_DLL

Defined when /MD or /MDd (Multithread DLL) is specified.

__FUNCDNAME__

Valid only within a function and returns the decorated name of the enclosing function (as a string). __FUNCDNAME__ is not expanded if you use the /EP or /P compiler option.

__FUNCSIG__

Valid only within a function and returns the signature of the enclosing function (as a string). __FUNCSIG__ is not expanded if you use the /EP or /P compiler option.

On a 64-bit operating system, the calling convention is __cdecl by default.

__FUNCTION__

Valid only within a function and returns the undecorated name of the enclosing function (as a string). __FUNCTION__ is not expanded if you use the /EP or /P compiler option.

_INTEGRAL_MAX_BITS

Reports the maximum size (in bits) for an integral type.

// integral_max_bits.cpp
#include <stdio.h>
int main() {
   printf("%d\n", _INTEGRAL_MAX_BITS);
}

_M_ALPHA

Defined for DEC ALPHA platforms (no longer supported).

_M_CEE

Defined for a compilation that uses any form of /clr (/clr:oldSyntax, /clr:safe, for example).

_M_CEE_PURE

Defined for a compilation that uses /clr:pure.

_M_CEE_SAFE

Defined for a compilation that uses /clr:safe.

_M_IX86

Defined for x86 processors. See Values for _M_IX86 for more details. This is not defined for x64 processors.

_M_IA64

Defined for Itanium Processor Family 64-bit processors.

_M_IX86_FP

Expands to a value indicating which /arch compiler option was used:

• 0 if /arch was not used.

• 1 if /arch:SSE was used.

• 2 if /arch:SSE2 was used.

• See /arch (Minimum CPU Architecture) for more information.

_M_MPPC

Defined for Power Macintosh platforms (no longer supported).

_M_MRX000

Defined for MIPS platforms (no longer supported).

_M_PPC

Defined for PowerPC platforms (no longer supported).

_M_X64

Defined for x64 processors.

_MANAGED

Defined to be 1 when /clr is specified.

_MFC_VER

Defines the MFC version. For example, 0x0700 represents MFC version 7.

_MSC_BUILD

Evaluates to the revision number component of the compiler's version number. The revision number is the fourth component of the period-delimited version number. For example, if the version number of the VC++ compiler is 15.00.20706.01, the _MSC_BUILD macro evaluates to 1.

_MSC_EXTENSIONS

This macro is defined when compiling with the /Ze compiler option (the default). Its value, when defined, is 1.

_MSC_FULL_VER

Evaluates to the major, minor, and build number components of the compiler's version number. The major number is the first component of the period-delimited version number, the minor number is the second component, and the build number is the third component. For example, if the version number of the VC++ compiler is 15.00.20706.01, the _MSC_FULL_VER macro evaluates to 150020706. Type cl /? at the command line to view the compiler's version number.

_MSC_VER

Evaluates to the major and minor number components of the compiler's version number. The major number is the first component of the period-delimited version number and the minor number is the second component.

For example, if the version number of the VC++ compiler is 15.00.20706.01, the _MSC_VER macro evaluates to 1500.

__MSVC_RUNTIME_CHECKS

Defined when one of the /RTC compiler options is specified.

_MT

Defined when /MD or /MDd (Multithreaded DLL) or /MT or /MTd (Multithreaded) is specified.

_NATIVE_WCHAR_T_DEFINED

Defined when /Zc:wchar_t is used.

_OPENMP

Defined when compiling with /openmp, returns an integer representing the date of the OpenMP specification implemented by Visual C++.

// _OPENMP_dir.cpp
// compile with: /openmp 
#include <stdio.h> 
int main() {
   printf("%d\n", _OPENMP);
}

_VC_NODEFAULTLIB

Defined when /Zl is used; see /Zl (Omit Default Library Name) for more information.

_WCHAR_T_DEFINED

Defined when /Zc:wchar_t is used or if wchar_t is defined in a system header file included in your project.

_WIN32

Defined for applications for Win32 and Win64. Always defined.

_WIN64

Defined for applications for Win64.

_Wp64

Defined when specifying /Wp64.

Blend

/GB

_M_IX86 = 600 (Default. Future compilers will emit a different value to reflect the dominant processor.)

Pentium

/G5

_M_IX86 = 500

Pentium Pro, Pentium II, and Pentium III

/G6

_M_IX86 = 600

80386

/G3

_M_IX86 = 300

80486

/G4

_M_IX86 = 400