svipc/t_ftok.c

This is svipc/t_ftok.c, an example to accompany the book, The Linux Programming Interface.

This file is not printed in the book; it is the solution to Exercise 45-2 (page 936).

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 svipc/t_ftok.c

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

main()

/* t_ftok.c

   Test the key values returned by ftok(3).

   Usage: t_ftok key-file key-char

   Simply calls ftok(), using the values supplied in the command-line arguments,
   and displays the resulting key.
*/
#include <sys/ipc.h>
#include <sys/stat.h>
#include "tlpi_hdr.h"

int
main(int argc, char *argv[])
{
    if (argc != 3 || strcmp(argv[1], "--help") == 0)
        usageErr("%s file-name keychar\n", argv[0]);

    printf("Size of key_t = %ld bytes\n", (long) sizeof(key_t));

    struct stat sb;
    if (stat(argv[1], &sb) == -1)
        errExit("stat");

    key_t key = ftok(argv[1], argv[2][0]);
    if (key == -1)
        errExit("ftok");

    printf("Key = %lx i-node = %lx st_dev = %lx proj = %x\n",
          (unsigned long) key, (unsigned long) sb.st_ino,
          (unsigned long) sb.st_dev, (unsigned int) argv[2][0]);
    if (key == -1)
        printf("File does not exist\n");

    exit(EXIT_SUCCESS);
}

Download svipc/t_ftok.c

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