14-5-thread-handle-signal.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <pthread.h>
#include <errno.h>

#define handle_error_en(en, msg) \
    do { errno = en; perror(msg); exit(EXIT_FAILURE);} while(0);

static void *sig_thread(void *arg)
{
    sigset_t *set = (sigset_t *)arg;
    int s, sig;
    for(;;)
    {
        //第二个步骤，调用sigwait等待信号
        s = sigwait(set, &sig);
        if (s != 0) 
        {
            handle_error_en(s, "sigwait");
        }
        printf("signal handling thread got signal %d\n", sig);
    }
}

int main(int argc, const char *argv[])
{
    pthread_t thread;
    sigset_t set;
    int s;

    //第一个步骤，在主线程中设置信号掩码
    sigemptyset(&set);
    sigaddset(&set, SIGQUIT);
    sigaddset(&set, SIGUSR1);
    s = pthread_sigmask(SIG_BLOCK, &set, NULL);
    if (s != 0) 
    {
        handle_error_en(s, "pthread_sigmask");
    }
    s = pthread_create(&thread, NULL, &sig_thread, (void *)&set);
    if (s != 0) 
    {
        handle_error_en(s, "pthread_create");
    }
    pause();
    return 0;
}

//明确地将信号发给指定线程
//int pthread_kill(pthread_t thread, int sig);
//