信号的转存，进程的挂起/激活（二）

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

void sig_int(int signo) {
    printf("got signal:%d\n", signo);
}

int main(void) {
    printf("\nprogram start\n");


    sigset_t sig_usr1;

    signal(SIGUSR1, sig_int);
    signal(SIGUSR2, sig_int);

    sigemptyset(&sig_usr1);
    sigaddset(&sig_usr1, SIGUSR1);


    printf("in critical region\n");

    sigsuspend(&sig_usr1); //忽略以前设置，挂起usr1信号，先放行其他，最后放行usr1，恢复以前设置，返回

    printf("out critical region\n");


    printf("program exit\n");
    return 0;
}

运行：

[mofan@localhost Debug]$ ./a.out &
[1] 57657
[mofan@localhost Debug]$
program start
in critical region
[mofan@localhost Debug]$ kill -USR1 57657
[mofan@localhost Debug]$ kill -USR1 57657
[mofan@localhost Debug]$ kill -USR2 57657
got signal:12
got signal:10
out critical region
program exit