孤儿进程、僵尸进程

孤儿进程：父进程先于子进程结束，则子进程成为孤儿进程，子进程的父进程成为init进程，称为init进程领养孤儿进程。

/***
orphan.c
***/
#include <stdio.h>
#include <unistd.h>
#include <sys/wait.h>int main(void)
{pid_t pid;pid = fork();if (pid == 0) {while (1) {printf("I am child, my parent pid = %d\n", getppid());sleep(1);}} else if (pid > 0) {printf("I am parent, my pid is = %d\n", getpid());sleep(9);printf("------------parent going to die------------\n");} else {perror("fork");return 1;}return 0;
}

僵尸进程：

进程终止，父进程尚未回收，子进程残留资源（PCB）存放于内核中，变为僵尸进程。

/***
zoom.c
***/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>int main(void)
{pid_t pid, wpid;pid = fork();if (pid == 0) {printf("---child, my parent= %d, going to sleep 10s\n", getppid());sleep(10);printf("-------------child die--------------\n");} else if (pid > 0) {while (1) {printf("I am parent, pid = %d, myson = %d\n", getpid(), pid);sleep(1);}} else {perror("fork");return 1;}return 0;
}