This is procexec/make_zombie.c (Listing 26-4, page 554), an example from the book, The Linux Programming Interface.

The source code file is copyright 2022, Michael Kerrisk, and is licensed under the GNU General Public License, version 3.

This page shows the "distribution" or "book" version of the file (why are there two versions?), or the differences between the two versions. You can switch between the views using the tabs below.

In the listing below, the names of Linux system calls and C library functions are hyperlinked to manual pages from the Linux man-pages project, and the names of functions implemented in the book are hyperlinked to the implementations of those functions.


Download procexec/make_zombie.c

  Cover of The Linux Programming Interface

Function list (Bold in this list means a function is not static)

/* make_zombie.c

   Demonstrate how a child process becomes a zombie in the interval between
   the time it exits, and the time its parent performs a wait (or exits, at
   which time it is adopted by init(8), which does a wait, thus releasing
   the zombie).
#include <signal.h>
#include <libgen.h>             /* For basename() declaration */
#include "tlpi_hdr.h"

#define CMD_SIZE 200
main(int argc, char *argv[])
    char cmd[CMD_SIZE];
    pid_t childPid;

    setbuf(stdout, NULL);       /* Disable buffering of stdout */

    printf("Parent PID=%ld\n", (long) getpid());

    switch (childPid = fork()) {
    case -1:

    case 0:     /* Child: immediately exits to become zombie */
        printf("Child (PID=%ld) exiting\n", (long) getpid());

    default:    /* Parent */
        sleep(3);               /* Give child a chance to start and exit */
        snprintf(cmd, CMD_SIZE, "ps | grep %s", basename(argv[0]));
        system(cmd);            /* View zombie child */

        /* Now send the "sure kill" signal to the zombie */

        if (kill(childPid, SIGKILL) == -1)
        sleep(3);               /* Give child a chance to react to signal */
        printf("After sending SIGKILL to zombie (PID=%ld):\n", (long) childPid);
        system(cmd);            /* View zombie child again */



Download procexec/make_zombie.c

Note that, in most cases, the programs rendered in these web pages are not free standing: you'll typically also need a few other source files (mostly in the lib/ subdirectory) as well. Generally, it's easier to just download the entire source tarball and build the programs with make(1). By hovering your mouse over the various hyperlinked include files and function calls above, you can see which other source files this file depends on.

Valid XHTML 1.1