##的用法

#include <stdio.h>

// 打印数字
void printf_number(int num)
{
    printf("number is %d\n", num);
    return ;
}

// 打印字符串
void printf_string(char *str)
{
    printf("string is %s\n", str);
    return ;
}

// 工厂模式打印
#define PRINT(type, value) {    \
    printf_##type(value);       \
}

int main()
{
    PRINT(number, 123);
    PRINT(string, "yes");
    return 0;
}

https://www.cnblogs.com/caosiyang/archive/2012/08/21/2648870.html 从下面函数中需要注意，宏定义也是需要进行可变参数，而不是像普通传递函数那样。

#define IS_USE_OUTPUT_DEBUG_PRINT   1

#if  IS_USE_OUTPUT_DEBUG_PRINT 

#define  OUTPUT_DEBUG_PRINTF(str, ...)  OutputDebugPrintf(str, ##__VA_ARGS__)
void OutputDebugPrintf(const char * strOutputString, ...)
{
#define PUT_PUT_DEBUG_BUF_LEN   4096
    char strBuffer[PUT_PUT_DEBUG_BUF_LEN] = { 0 };
    va_list vlArgs;
    va_start(vlArgs, strOutputString);
    _vsnprintf_s(strBuffer, sizeof(strBuffer) - 1, strOutputString, vlArgs);  //_vsnprintf_s  _vsnprintf
                                                                              //vsprintf(strBuffer,strOutputString,vlArgs);
    va_end(vlArgs);
    OutputDebugStringA(strBuffer);  //OutputDebugString    // OutputDebugStringW

}
#else 
#define  OUTPUT_DEBUG_PRINTF(str) 
#endif

#define TRACE_HEADER "[keyboard]"
void DbgPrint(const char* format, ...)
{
    char line[4096 + sizeof(TRACE_HEADER)] = { 0 };
    char* buf = line + sizeof(TRACE_HEADER);
    va_list ap;
    strcpy(line, TRACE_HEADER);
    line[sizeof(TRACE_HEADER) - 1] = ' ';
    va_start(ap, format);
    _vsnprintf(buf, 4095, format, ap);
    va_end(ap);
    OutputDebugStringA(line);
}