#define _BSD_SOURCE     /* Get on_exit() declaration from <stdlib.h> */
#include <stdlib.h>
#include "tlpi_hdr.h"

static void
atexitFunc1(void)
{
    printf("atexit function 1 called\n");
}

static void
atexitFunc2(void)
{
    printf("atexit function 2 called\n");
}

static void
onexitFunc(int exitStatus, void *arg)
{
    printf("on_exit function called: status=%d, arg=%ld\n",
                exitStatus, (long) arg);
}

int
main(int argc, char *argv[])
{
    if (on_exit(onexitFunc, (void *) 10) != 0)
        fatal("on_exit 1");
    if (atexit(atexitFunc1) != 0)
        fatal("atexit 1");
    if (atexit(atexitFunc2) != 0)
        fatal("atexit 2");
    if (on_exit(onexitFunc, (void *) 20) != 0)
        fatal("on_exit 2");

    exit(2);
}

/*************************************************************************\
*                  Copyright (C) Michael Kerrisk, 2017.                   *
*                                                                         *
* This program is free software. You may use, modify, and redistribute it *
* under the terms of the GNU General Public License as published by the   *
* Free Software Foundation, either version 3 or (at your option) any      *
* later version. This program is distributed without any warranty.  See   *
* the file COPYING.gpl-v3 for details.                                    *
\*************************************************************************/

/* Listing 25-2 */

#include "tlpi_hdr.h"

int
main(int argc, char *argv[])
{
    printf("Hello world\n");
    write(STDOUT_FILENO, "Ciao\n", 5);

    if (fork() == -1)
        errExit("fork");

    /* Both child and parent continue execution here */

    exit(EXIT_SUCCESS);
}