* 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>
wait() should wait only once. If any argument is given, waitpid() should return
an error (and errno to ECHILD), since there is no child with that process group ID.
*/
int
child2()
{
sleep(3);
return 2;
}
int
child1()
{
pid_t child = fork();
if (child == 0)
return child2();
sleep(1);
setpgrp();
sleep(1);
return 1;
}
int
main(int argc, char** argv)
{
bool waitForGroup = argc > 1;
pid_t child = fork();
if (child == 0)
return child1();
pid_t pid;
do {
int childStatus = -1;
if (waitForGroup)
pid = waitpid(0, &childStatus, 0);
else
pid = wait(&childStatus);
printf("wait() returned %ld (%s), child status %d\n",
pid, strerror(errno), childStatus);
} while (pid >= 0);
return 0;
}
