Demo of creating zombie process.

test-zombie.c

/*
 * Demo of creating zombie process.
 * Build: gcc test-zombie.c -o test-zombie
 * Run: ./test-zombie
 */

#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <stdlib.h>

int main()
{
  pid_t pid;
  pid = fork();
  if (pid < 0)
  {
    perror("fork error:");
    exit(1);
  }
  else if (pid == 0)
  {
    printf("I am child process.I am exiting.\n");
    exit(0);
  }
  printf("I am father process.I will sleep two seconds\n");
  //等待子进程先退出
  sleep(2);
  //输出进程信息
  system("ps -o pid,ppid,state,tty,command");
  printf("father process is exiting.\n");
  return 0;
}

Program output:

I am father process.I will sleep two seconds
I am child process.I am exiting.
PID PPID S TT COMMAND
98698 98697 S pts/0 -bash
107301 98698 S pts/0 ./test-zombie.out
107302 107301 Z pts/0 [test-zombie.out] ---------zombie process here
107303 107301 R pts/0 ps -o pid,ppid,state,tty,command
father process is exiting.