# define	KEYSIZE	12
# define	DLOCKS	10	/* max number of data base locks (limits # of ingreses */
# define	RLOCKS	2*DLOCKS + 6
# define	PLOCKS	RLOCKS + 3
# define	NLOCKS	PLOCKS + 1
# define	LOCKPRI	1
# define	TRUE	1
# define	FALSE	0
# define	M_EMTY		0
# define	M_SHARE		2
# define	M_EXCL		1
# define	T_CS		0
# define	T_PAGE		1
# define	T_REL		2
# define	T_DB		3
# define	A_RTN		1
# define	A_SLP		2
# define	A_RLS1		3
# define	A_RLSA		4
# define	A_ABT		5
# define	W_ON		1
# define	W_OFF		0
/*	Device driver for the /dev/ILOCK 
 *	an in core device used as a Lock table
 */
/* Only the parameters NLOCKS, PLOCKS, RLOCKS and DLOCKS
 * may be changed by an INGRES installation.  See 
 * 'HOW TO INSTALL CONCURRENCY DEVICE' for details.
 * The file can be printed by "nroff .../doc/other/lockdev.nr"
 */
/*
 *	data structure for Lock table
 */
struct	Lockform
{
	int	l_pid;
	char	l_wflag;	/* wait flag: = 1 a process is waiting*/
	char	l_type;		/* type of lock:
					= 0 for critical section
					= 1 for page
					= 2 for logical
					= 3 for data base
				*/
	char	l_mod;		/* mod of Lock or lock action requested 
				 *	= 0 slot empty
				 *	= 1 exclusive lock
				 *	= 2 shared lock
				 */
	char l_key[KEYSIZE];
}	Locktab[NLOCKS];

int	Lockset[]
			/* array of number of locks which can be
			 * set for each lock.
			 */
{
	NLOCKS,
	PLOCKS,
	RLOCKS,
	DLOCKS
};

struct Lockreq
			/* Lock Request */
{
	int	lr_pid;		/* requesting process id */
	char	lr_act;		/* requested action:
				 *	=1 request lock, err return
				 *	=2 request lock, sleep
				 *	=3 release lock
				 *	=4 release all locks for pid
				 */
	char	lr_type;	/* same as Locktab l_type */
	char	lr_mod;		/* same as Locktab l_mod */
	char	lr_key[KEYSIZE];/* requested key	*/
};