C语言父子进程--waitpid的用法

#include <stdio.h>#include <sys/types.h>#include <sys/wait.h>#include <unistd.h>#include <stdlib.h>#include <fcntl.h>#include <error.h>int main(int argc ,char **argv){pid_t pid;pid_t pid_c;int status;pid=fork();if(pid==0){printf("child process will sleep 3 seconds\n");sleep(3);printf("child PID[%d] will exit with status 3.\n",getpid());exit(3);}else if(pid>0){do{pid_c=waitpid(pid,&status,WNOHANG);if(pid_c==0){printf("NO child process exit\n");sleep(1);}}while(pid_c==0);if(WIFEXITED(status)){printf("child process %d will exit normally\n",pid_c);printf("return code is %d\n",WEXITSTATUS(status));}else {printf("child process %d will exit normally\n",pid_c);}}else{printf("error");exit(1);}return 0;}