#define PERM 0666
#define MAXBUFF 80

typedef struct mem_msg {
    int segment;
    char buff[MAXBUFF];
} Message;

static struct sembuf mem_lock[2] = { 0, 0, 0, 0, 1, 0 };
static struct sembuf mem_unlock[1] = { 0, -1, 0 };
static struct sembuf proc_wait[1] = { 1, -1, 0 };
static struct sembuf proc_start[1] = { 1, 1, 0 };