linux/unix 防止子进程变为僵尸（zombie）进程

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

void sighandler_t(int nu)
{

pid_t  pid;
pid = wait(NULL);
printf("child process exit, pid:%x\n",pid);

}
int main()
{

pid_t pid;

signal(SIGCHLD, sighandler_t);

if((pid= fork())<0){
    perror("fork err");
}else if(pid == 0){ 

    printf("I am child1,myPid:%x\n",getpid());
    sleep(1);
    _exit(0);

}


if((pid= fork())<0){
    perror("fork err");
}else if(pid == 0){

    printf("I am child2,myPid:%x\n",getpid());
    sleep(2);
    _exit(0);

}

while(1){

    printf("parent:%x\n",getpid());
    sleep(2);

}
exit(0);

}