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39 lines
980 B
C
39 lines
980 B
C
/*-------------------------------------------------------------------------
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*
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* buf.h
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* Basic buffer manager data types.
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*
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*
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* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/storage/buf.h,v 1.20 2006/03/05 15:58:59 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef BUF_H
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#define BUF_H
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/*
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* Buffer identifiers.
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*
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* Zero is invalid, positive is the index of a shared buffer (1..NBuffers),
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* negative is the index of a local buffer (-1 .. -NLocBuffer).
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*/
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typedef int Buffer;
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#define InvalidBuffer 0
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/*
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* BufferIsInvalid
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* True iff the buffer is invalid.
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*/
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#define BufferIsInvalid(buffer) ((buffer) == InvalidBuffer)
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/*
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* BufferIsLocal
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* True iff the buffer is local (not visible to other backends).
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*/
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#define BufferIsLocal(buffer) ((buffer) < 0)
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#endif /* BUF_H */
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