Lists the predefined ANSI C and Microsoft C++ implementation macros.
The compiler recognizes predefined ANSI C macros and the Microsoft C++ implementation provides several more. These macros take no arguments and cannot be redefined. Some of the predefined macros listed below are defined with multiple values. See the following tables for more information.
Macro |
Description |
---|---|
__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). |
__LINE__ |
The line number in the current source file. The line number is a decimal integer constant. It can be changed 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. |
Macro |
Description |
---|---|
_ATL_VER |
Defines the ATL version. In Visual Studio 2010, _ATL_VER is defined as 0x0A00. |
_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,
// clr_ver.cpp // compile with: /clr using namespace System; int main() { Console::WriteLine(__CLR_VER); } |
__cplusplus_cli |
Defined when you compile 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 source file or included headers of the source file.__COUNTER__ remembers its state when you use precompiled headers. The following example uses __COUNTER__ to assign unique identifiers to three different objects of the same type. First, assume the following class definition. The constructor takes an integer as a parameter.
C++
// initialize object with a read-only unique ID exampleClass::exampleClass(int nID) { m_nID = nID; } int exampleClass::GetID() { return m_nID; } In main, the application declares three objects of type exampleClass, using __COUNTER__ as the unique identifier parameter.
C++
// Demonstration of __COUNTER__, assigns unique identifiers to // different objects of the same type int main(int argc, char** argv) { // __COUNTER__ is initially defined as 0 exampleClass e1(__COUNTER__); // having been referenced, __COUNTER__ is now defined as 1 exampleClass e2(__COUNTER__); // __COUNTER__ is now defined as 2 exampleClass e3(__COUNTER__); printf("e1 ID: %i\n", e1.GetID()); printf("e2 ID: %i\n", e2.GetID()); printf("e3 ID: %i\n", e3.GetID()); // Output // ------------------------------ // e1 ID: 0 // e2 ID: 1 // e3 ID: 2 return 0; } |
__cplusplus |
Defined for C++ programs only. |
_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 you compile with /LDd, /MDd, and /MTd. |
_DLL |
Defined when /MD or /MDd (Multithreaded DLL) is specified. |
__FUNCDNAME__ |
Valid only in a function. Defines the decorated name of the enclosing function as a string. __FUNCDNAME__ is not expanded if you use the /EP or /P compiler option. The following example uses the __FUNCDNAME__, __FUNCSIG__, and __FUNCTION__ macros to display function information.
C++
// Demonstrates functionality of __FUNCTION__, __FUNCDNAME__, and __FUNCSIG__ macros void exampleFunction() { printf("Function name: %s\n", __FUNCTION__); printf("Decorated function name: %s\n", __FUNCDNAME__); printf("Function signature: %s\n", __FUNCSIG__); // Sample Output // ------------------------------------------------- // Function name: exampleFunction // Decorated function name: ?exampleFunction@@YAXXZ // Function signature: void __cdecl exampleFunction(void) } |
__FUNCSIG__ |
Valid only in a function. Defines 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. See __FUNCDNAME__ for an example. |
__FUNCTION__ |
Valid only in a function. Defines the undecorated name of the enclosing function as a string. __FUNCTION__ is not expanded if you use the /EP or /P compiler option. See __FUNCDNAME__ for an example. |
_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_AMD64 |
Defined for x64 processors. |
_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 the Values for _M_IX86 table below for more information. 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:
|
_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, in Visual Studio 2010, _MFC_VER is defined as 0x0A00. |
_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 Visual C++ compiler is 15.00.20706.01, the _MSC_BUILDmacro evaluates to 1. |
_MSC_EXTENSIONS |
This macro is defined when you compile 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 Visual C++ 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 Visual C++ compiler is 15.00.20706.01, the _MSC_VER macro evaluates to 1500. In Visual Studio 2010, _MSC_VER is defined as 1600. |
__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. |
As shown in following table, the compiler generates a value for the preprocessor identifiers that reflect the processor option specified.
Option in Development Environment |
Command-Line Option |
Resulting Value |
---|---|---|
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 |
注:本文转载自:http://msdn.microsoft.com/en-us/library/b0084kay(v=vs.100).aspx