实时信号和非实时信号

Posted 2020-09-02 bangiao

#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>

void myHandler(int num)
{
    int ret = 0;
    
    if (SIGUSR1 == num)
    {
        sigset_t set;
        ret = sigemptyset(&set);
        assert(!(-1 == ret));
        ret = sigaddset(&set, SIGINT);
        assert(!(-1 == ret));
        ret = sigaddset(&set, SIGRTMIN);
        assert(!(-1 == ret));
        ret = sigprocmask(SIG_UNBLOCK, &set, NULL);
        assert(!(-1 == ret));
        printf("解除阻塞 recv sig num: %d\n", num);
    }
    else if (num == SIGINT || num == SIGRTMIN)
    {
        printf("recv sig num: %d\n", num);
    }
    else
    {
        printf(" 其他信号recv sig num: %d\n", num);
    }
}

int main(void)
{
    pid_t pid;
    int ret = 0;
    // 设置回调函数
    struct sigaction act;
    act.sa_handler = myHandler;
    act.sa_flags = SA_SIGINFO;
    // 注册非实时信号的处理函数
    ret = sigaction(SIGINT, &act, NULL);
    assert(!(-1 == ret));
    // 注册实时信号的处理函数
    ret = sigaction(SIGRTMIN, &act, NULL);
    assert(!(-1 == ret));
    // 注册用户自定义信号
    ret = sigaction(SIGUSR1, &act, NULL);
    assert(!(-1 == ret));
    
    // 把 SIGINT  SIGRTMIN 军添加到阻塞状态字中
    sigset_t set;
    ret = sigemptyset(&set);
    assert(!(-1 == ret));
    ret = sigaddset(&set, SIGINT);
    assert(!(-1 == ret));
    ret = sigaddset(&set, SIGRTMIN);
    assert(!(-1 == ret));
    ret = sigprocmask(SIG_BLOCK, &set, NULL);
    assert(!(-1 == ret));
    
    pid = fork();
    assert(!(-1 == ret));
    if (0 == pid)
    {
        union sigval value;
        value.sival_int = 10;
        int i = 0;
        // 发三次不稳定信号
        for (i = 0; i < 3; i++)
        {
            ret = sigqueue(getppid(), SIGINT, value);
            assert(!(-1 == ret));
            printf("发送不可靠信号 ok\n");
        }
        
        // 发三次稳定信号
        value.sival_int = 20;
        for (i = 0; i < 3; i++)
        {
            ret = sigqueue(getppid(), SIGRTMIN, value);
            assert(!(-1 == ret));
            printf("发送可靠信号ok\n");
        }
        // 向父进程发送 SIGUSR1 解除阻塞
        ret = kill(getppid(), SIGUSR1);
        assert(!(-1 == ret));
    }
    while (1)
    {
        sleep(1);
    }
    return 0;
}