c语言实现信号捕捉

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

//设置绑定的信号函数句柄
void sig_handler(int signo){
    //打印接收到的信号
    printf("%d\n", signo);
}
int main(){
    struct sigaction act, oact;
    sigset_t newmask, oldmask, suspmask;
    while(1){ 
        act.sa_handler = sig_handler;
        sigemptyset(&(act.sa_mask));
        act.sa_flags = 0;
        //内核中注册SIGALRM信号
        sigaction(SIGALRM, &act, &oact);

        sigemptyset(&newmask);
        sigaddset(&newmask, SIGALRM);
        //屏蔽SIGALRM信号
        sigprocmask(SIG_BLOCK, &newmask, &oldmask);
        //设置时钟
        alarm(3);
        //进程挂起等待时钟超时
        //pause();
        sigdelset(&suspmask, SIGALRM);
        //解除SIGALRM信号屏蔽并等待
        sigsuspend(&suspmask);
        //取消闹钟
        alarm(0);
        //3秒钟时间过后发送时钟信号，SIGALRM信号递达后suspend自动恢复屏蔽
        sigaction(SIGALRM, &oact, NULL);
        //解除屏蔽
        sigprocmask(SIG_SETMASK, &oldmask, NULL);
    };//穷忙
    return 0;
}