sigusr1 사용하는데 질문드립니다.

void sighandler(int signum)
{
    if(signum == SIGUSR1){
        printf("succcess\n");
    }
    else{
        printf("fail\n");
    }
}
 
 
int main(int argc, char *argv[])
{
    pid_t pid;
 
    pid = fork();
 
    struct sigaction sa2;
    sa2.sa_handler = sighandler;
    sa2.sa_flags=0;
    sigemptyset(&sa2.sa_mask);
    sigaction(SIGUSR1,&sa2,NULL);
 
    if(pid==0){
    {
       kill(getppid(),SIGUSR1);
       exit(0);
    }
    //parent
    signal(SIGUSR1,sighandler);
}