/*
 * Copyright 2007, Jérôme Duval. 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()/waitpid() should return -1 and set errno to ECHILD, since there
        are no children to wait for.
*/
int
main()
{
        int childStatus;
        pid_t pid = wait(&childStatus);
        printf("wait() returned %ld (%s)\n", pid, strerror(errno));

        pid = waitpid(-1, &childStatus, 0);
        printf("waitpid(-1, ...) returned %ld (%s)\n", pid, strerror(errno));

        pid = waitpid(0, &childStatus, 0);
        printf("waitpid(0, ...) returned %ld (%s)\n", pid, strerror(errno));

        pid = waitpid(getpgrp(), &childStatus, 0);
        printf("waitpid(%ld, ...) returned %ld (%s)\n", getpgrp(), pid, strerror(errno));

        return 0;
}