1 /*-------------------------------------------------------------------------
4 * Basic buffer manager data types.
7 * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
8 * Portions Copyright (c) 1994, Regents of the University of California
10 * $Id: buf.h,v 1.10 2001/10/25 05:50:09 momjian Exp $
12 *-------------------------------------------------------------------------
20 * Zero is invalid, positive is the index of a shared buffer (1..NBuffers),
21 * negative is the index of a local buffer (-1 .. -NLocBuffer).
25 #define InvalidBuffer 0
29 * True iff the buffer is invalid.
31 #define BufferIsInvalid(buffer) ((buffer) == InvalidBuffer)
35 * True iff the buffer is local (not visible to other servers).
37 #define BufferIsLocal(buffer) ((buffer) < 0)
40 * If NO_BUFFERISVALID is defined, all error checking using BufferIsValid()
41 * are suppressed. Decision-making using BufferIsValid is not affected.
42 * This should be set only if one is sure there will be no errors.
45 #undef NO_BUFFERISVALID