Function BufferGetBlockNumber

src/backend/storage/buffer/bufmgr.c:2912–2926

* BufferGetBlockNumber * Returns the block number associated with a buffer. * * Note: * Assumes that the buffer is valid and pinned, else the * value may be obsolete immediately... */

 *		value may be obsolete immediately...
 */
BlockNumber
BufferGetBlockNumber(Buffer buffer)
{
	BufferDesc *bufHdr;

	Assert(BufferIsPinned(buffer));

	if (BufferIsLocal(buffer))
		bufHdr = GetLocalBufferDescriptor(-buffer - 1);
	else
		bufHdr = GetBufferDescriptor(buffer - 1);

	/* pinned, so OK to read tag without spinlock */
	return bufHdr->tag.blockNum;
}

/*
 * BufferGetTag