procexec/t_fork.c

This is procexec/t_fork.c (Listing 24-1, page 517), an example from the book, The Linux Programming Interface.

The source code file is copyright 2024, Michael Kerrisk, and is licensed under the GNU General Public License, version 3.

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  Cover of The Linux Programming Interface

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

/* t_fork.c

   Demonstrate the use of fork(), showing that parent and child
   get separate copies of stack and data segments.
*/
#include "tlpi_hdr.h"

static int idata = 111;             /* Allocated in data segment */
int
main(int argc, char *argv[])
{
    int istack = 222;               /* Allocated in stack segment */
    pid_t childPid;

    switch (childPid = fork()) {
    case -1:
        errExit("fork");

    case 0:
        idata *= 3;
        istack *= 3;
        break;

    default:
        sleep(3);                   /* Give child a chance to execute */
        break;
    }

    /* Both parent and child come here */

    printf("PID=%ld %s idata=%d istack=%d\n", (long) getpid(),
            (childPid == 0) ? "(child) " : "(parent)", idata, istack);

    exit(EXIT_SUCCESS);
}

 

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