C++定义的宏

void Foo(){
printf("%s\n", __func__);
} // prints “Foo”

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

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;
}

__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: [email protected]@YAXXZ 
	// Function signature: void __cdecl exampleFunction(void)
}

__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__ is not expanded if you use the /EP or /P compiler option.

See __FUNCDNAME__ for an example.

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

• In the range 30-39 if no /arch ARM option was specified, indicating the default architecture for ARM was used (VFPv3).
• In the range 40-49 if /arch:VFPv4 was used.
• See /arch (x86) for more information.

• 0 if /arch:IA32 was used.
• 1 if /arch:SSE was used.
• 2 if /arch:SSE2, /arch:AVX or /arch:AVX2 was used. This value is the default if /arch was not specified. When /arch:AVX is specified, the macro __AVX__ is also defined. When /arch:AVX2 is specified, __AVX__and __AVX2__ are also defined.
• See /arch (x86) for more information.

For example, if the version number of the Visual C++ compiler is 17.00.51106.1, the _MSC_VER macro evaluates to 1700. Type cl /? at the command line to view the compiler‘s version number.

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