int semget(key_t key, int nsems, int semflg);
int semctl(int semid, int semnum, int cmd, ...);
int shmget(key_t key, size_t size, int shmflg);
int shmctl(int shmid, int cmd, struct shmid_ds *buf);
void *shmat(int shmid, const void *shmaddr, int shmflag);
int shmdt(const void *shmaddr);
int msgget(key_t key, int msgflg);
int msgctl(int msqid, int cmd, struct msqid_ds *buf);
int msgsnd(int msqid, const void *msgp, size_t msgsz,
int msgflg);
ssize_t msgrcv(int msqid, void *msgp, size_t msgsz,
long msgtyp, int msgflg);
