逗号表达式的经典应用

经典的","逗号表达式的2种使用


    void bar(X &);
     X _temp;
     (  bar(_temp),temp ).memberfunction();


#include <stdio.h>
#include <stdlib.h>

//逗号表达式的最后一个值作为返回值
#define  sigfillset(ptr) ((*ptr = ~(0)), 0)


int main()
{
     static unsigned b;
     int c = 10;

     c = sigfillset(&b);

     printf("0x%x\n", b);
     printf("0x%x\n", c); //输出0

     system("pause");
}