struct	ipc_perm	{
		unsigned short	cuid;		/* creator uid */
		unsigned short	cgid;		/* creator group id */
		unsigned short  uid;		/* user id */
		unsigned short	gid;		/* group id */
		unsigned short	mode;		/* R/W permission */
};

struct	shmid_ds {
                struct	ipc_perm	shm_perm;	
						/* operation  permission 
							structure */
		int		shm_segsz;	/* size of segment */
		unsigned short	shm_cpid;	/* creator pid */
		unsigned short	shm_lpid;	/* pid of last operation */
		unsigned short	shm_nattach;	/* number of current attaches*/
		long		shm_atime;	/* last attach time */
		long		shm_dtime;	/* last detach time */
		long		shm_ctime;	/* last change time */
		/* times measured in secs since */
		/* 00:00:00 GMT Jan. 1, 1970    */
};

#define IPC_STAT	0
#define IPC_SET		1
#define IPC_RMID	2