15.11.c

#include <stdio.h>
#include <stdlib.h>
#include <sys/shm.h>

#define ARRAY_SIZE 4000
#define MALLOC_SIZE 100000
#define SHM_SIZE 100000
#define SHM_MODE 0600

char array[ARRAY_SIZE];

int main(void)
{
    int     shmid;
    char    *ptr, *shmptr;

    printf("array[] from %lx to %lx\n", (unsigned long)&array[0], (unsigned long)&array[ARRAY_SIZE]);
    printf("stack around %ld\n", (unsigned long)&shmid);

    if ((ptr = malloc(MALLOC_SIZE)) == NULL) {
        printf("malloc error\n");
        exit(-1);
    }

    printf("malloced from %lx to %lx\n", (unsigned long)ptr, (unsigned long)ptr + MALLOC_SIZE);

    if ((shmid = shmget(IPC_PRIVATE, SHM_SIZE, SHM_MODE)) < 0) {
        printf("shmget error\n");
        exit(-1);
    }

    if ((shmptr = shmat(shmid, 0, 0)) == (void *)-1) {
        printf("shmat error\n");
    }

    printf("shared memory attached from %lx to %lx\n", (unsigned long)shmptr, (unsigned long)shmptr+SHM_SIZE);

    if (shmctl(shmid, IPC_RMID, 0) < 0) {
        printf("shmctl error\n");
        exit(-1);
    }

    return 0;
}