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/*-------------------------------------------------------------------------
*
* buf.h
* Basic buffer manager data types.
*
*
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: buf.h,v 1.9 2001/06/09 18:16:59 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#ifndef BUF_H
#define BUF_H
/*
* Buffer identifiers.
*
* Zero is invalid, positive is the index of a shared buffer (1..NBuffers),
* negative is the index of a local buffer (-1 .. -NLocBuffer).
*/
typedef int Buffer;
#define InvalidBuffer 0
/*
* BufferIsInvalid
* True iff the buffer is invalid.
*/
#define BufferIsInvalid(buffer) ((buffer) == InvalidBuffer)
/*
* BufferIsLocal
* True iff the buffer is local (not visible to other servers).
*/
#define BufferIsLocal(buffer) ((buffer) < 0)
/*
* If NO_BUFFERISVALID is defined, all error checking using BufferIsValid()
* are suppressed. Decision-making using BufferIsValid is not affected.
* This should be set only if one is sure there will be no errors.
* - plai 9/10/90
*/
#undef NO_BUFFERISVALID
#endif /* BUF_H */
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