数据库系统

开发平台：

Unix_Linux

sdir.h：源码内容

							/*-------------------------------------------------------------------------
 *
 * sdir.h
 *	  POSTGRES scan direction definitions.
 *
 *
 * Copyright (c) 1994, Regents of the University of California
 *
 * $Id: sdir.h,v 1.6 1999/05/25 16:13:34 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#ifndef SDIR_H
#define SDIR_H
/*
 * ScanDirection was an int8 for no apparent reason. I kept the original
 * values because I'm not sure if I'll break anything otherwise.  -ay 2/95
 */
typedef enum ScanDirection
{
	BackwardScanDirection = -1,
	NoMovementScanDirection = 0,
	ForwardScanDirection = 1
} ScanDirection;
/*
 * ScanDirectionIsValid
 *		True iff scan direction is valid.
 */
#define ScanDirectionIsValid(direction) 
	((bool) (BackwardScanDirection <= direction && 
			 direction <= ForwardScanDirection))
/*
 * ScanDirectionIsBackward
 *		True iff scan direction is backward.
 */
#define ScanDirectionIsBackward(direction) 
	((bool) (direction == BackwardScanDirection))
/*
 * ScanDirectionIsNoMovement
 *		True iff scan direction indicates no movement.
 */
#define ScanDirectionIsNoMovement(direction) 
	((bool) (direction == NoMovementScanDirection))
/*
 * ScanDirectionIsForward
 *		True iff scan direction is forward.
 */
#define ScanDirectionIsForward(direction) 
	((bool) (direction == ForwardScanDirection))
#endif	 /* SDIR_H */

						