进程间通讯：信号

#include <stdio.h>
#include <signal.h>
#include <unistd.h>

void handler (int num)
{
    printf ("handler is running\n");
}
int main()//测试哪个中断不能被自己所写的函数接管
{
    int i;
    for (i=0;i<32;i++)
        signal(i,handler);//中断处理
    while (1)
    {
        printf ("main is running,pid = %d\n",getpid());
        sleep (2);
    }
    return 0;
}