* Copyright 2007, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
* Distributed under the terms of the MIT License.
*/
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <sys/wait.h>
#include <unistd.h>
waitpid() should wait only once.
*/
int
child2()
{
printf("child 2 1. parent id = %ld\n", getppid());
sleep(2);
printf("child 2 2. parent id = %ld\n", getppid());
return 2;
}
int
child1()
{
printf("child 1 process group: %ld\n", getpgrp());
pid_t child = fork();
if (child == 0)
return child2();
sleep(1);
return 1;
}
int
main()
{
printf("main process group: %ld\n", getpgrp());
pid_t child = fork();
if (child == 0)
return child1();
pid_t pid;
do {
int childStatus = -1;
pid = waitpid(0, &childStatus, 0);
printf("waitpid() returned %ld (%s), child status %d\n", pid, strerror(errno), childStatus);
} while (pid >= 0);
return 0;
}
