2.11BSD/ingres/source/lock.h

/*
**	Concurency structs and global variables
*/
# 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	KEYSIZE		12
struct lockreq
{
	char	lract;			/* requested action
					 *	=1 request lock,err return
					 *	=2 request lock,sleep
					 *	=3 release lock
					 *	=release all locks for pid
					 */
	char	lrtype;			/* type of lock:
					 *   =0, critical section lock
					 *   =1, page lock
					 *   =2, logical lock
					 *   =3, data base lock
					 */
	char	lrmod;			/* mode of lock
					 *	=1 exclusive lock
					 *	=2 shared lock
					*/
	char	lpad;			/* padding to align the key */
					/* key for the lock */
	char	dbnode[4];		/* inode of data base */
	char	lrel[4];		/* relation tid */
	char	lpage[4];		/* page address		*/
};

char	Acclock;			/* locks enabled flag */
extern int	Alockdes;		/* file descriptor for lock device*/
int	Lockrel;			/* lock relations flag*/