47 lines
1.1 KiB
C
47 lines
1.1 KiB
C
/*-------------------------------------------------------------------------
|
|
*
|
|
* buf.h
|
|
* Basic buffer manager data types.
|
|
*
|
|
*
|
|
* Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
|
|
* Portions Copyright (c) 1994, Regents of the University of California
|
|
*
|
|
* src/include/storage/buf.h
|
|
*
|
|
*-------------------------------------------------------------------------
|
|
*/
|
|
#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 backends).
|
|
*/
|
|
#define BufferIsLocal(buffer) ((buffer) < 0)
|
|
|
|
/*
|
|
* Buffer access strategy objects.
|
|
*
|
|
* BufferAccessStrategyData is private to freelist.c
|
|
*/
|
|
typedef struct BufferAccessStrategyData *BufferAccessStrategy;
|
|
|
|
#endif /* BUF_H */
|