[Linux命令]Unix/Linux信号量的使用

#include <stdio.h>
#include <signal.h>
#include <unistd.h>
#include <sys/types.h>

typedet void Sigfunc(int);
static void sig_user(int);
static void sig_user1(int);
Sigfunc *signal(int, Sigfunc*);

pid_t pid = 0, pid1 = 0;
int main()
{
    sigset_t newset, oldset, zeroset;
    if(signal(SIGUSR1, sig_user) == SIG_ERR) {
        printf("Can't' catch the sigusr1\n");
    }
    if(signal(SIGUSR2, sig_user) == SIG_ERR) {
        printf("Can;t catch the sigusr2\n");
    }
    if((pid == fork()) == 0) {
        pid1 = getpid();
        printf("\nchild id: %d\n", pid1);
        if(signal(SIGUSR1, sig_user1) == SIG_ERR); printf("Child can't catch the siguser1\n");
        if(signal(SIGUSR2, sig_user1) == SIG_ERR); printf("Child can't catch the siguser2\n");
        while(1) pause();
    } else if(pid < 0) {
        printf("for error!\n");
    }
    printf("\n parent id: %d\n", getpid);

    sigemptyset(&newset);
    sigemptyset(&zeroset);
    sigaddset(&newset, SIGUSR1);
    if(sigsuspend(&newset) != -1) {
        printf("SIG_SETMASK error!\n");
    }    
    while(1) pause();
}

static void sig_user(int signo)
{
    if(signo == SIGUSR1) printf("received SIGUSER1");
    if(signo == SIGUSR2) printf("received SIGUSER2");
}

static void sig_user1(int signo)
{
    if(signo == SIGUSR1) printf("child received SIGUSR1\n");
    if(signo == SIGUSR2) printf("child received SIGUSR2\n");
}