#include <sys/types.h> #include <sys/ipc.h> #include <sys/msg.h> int msgget ( key_t key, int msgflg ); int msgctl ( int msgid, int cmd, struct msqid_ds *buf ); int msgsnd ( int msgid, structu msgbuf *msgp, size_t msgsz, _int msgflg ); size_t msgrcv ( int msgid, struct msgbuf *msgp, size_t msgsz, _long msgtyp, int msgflg );