#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <stdio.h>
#include <wait.h>
#include <stdlib.h>
#include <unistd.h>

int main(void)
{
    int key = 5678;
    int i = 65;

    /*
     * Create the segment.
     */
    int shmid;
    shmid = shmget(key, sizeof(int), IPC_CREAT | 0666);

     /*
     * Attach the segment to our data space.
     */
    int *shm;
    shm = shmat(shmid, NULL, 0);

    *shm = i;

    int pid = fork();
    //Son
    if (pid == 0){
    int reg = *shm;
    sleep(2);
    reg--;
        *shm = reg;
    exit(0);

    }
    //Father
    else{
        int reg = *shm;
    sleep(1);
    reg++;
    *shm = reg;
    }

    wait(NULL);
    printf("End --> valeur de shm: %d\n", *shm);
}