Elaborato_SO/src/custom_shm.c

#include <stdio.h>
#include <sys/shm.h>
#include <sys/stat.h>
#include <custom_shm.h>

#include <errExit.h>
#include <forza4.h>

int _SHMID;

int getShmid(int row, int col) {
    int shmid = shmget(ftok(KEYFILE, 'z'), row * col * sizeof(tile_t), IPC_CREAT | S_IRUSR | S_IWUSR);
    if (shmid == -1) {
        errExit("shmget", "getShmid");
    }

    return shmid;
}

tile_t * shmServerAt(int shmid) {
    tile_t *board = (tile_t *)shmat(shmid, NULL, 0); 
    if (board == SHMERR) {
        errExit("shmat", "shmServerAt");
    }
    
    return board;
}

tile_t * shmClientAt(int shmid) {
    tile_t *board = (tile_t *)shmat(shmid, NULL, SHM_RDONLY); 
    if (board == SHMERR) {
        errExit("shmat", "shmClientAt");
    }

    return board;
} 

void shmDt(void *shm_ptr) {
    if (shmdt(shm_ptr) == -1) {
        errExit("shmdt", "shmDt");
    }
}

void shmServerRm(int shmid) {
    if (shmctl(shmid, IPC_RMID, NULL) == -1) {
        errExit("shmctl", "shmServerRm");
    } 
}