Add comment about why "((void) 0)" is used in copy macros.

This commit is contained in:
Bruce Momjian 2009-06-03 14:48:33 +00:00
parent 44ead23384
commit 1a0ebe6152

View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/copy.c,v 1.309 2009/05/29 13:54:52 meskes Exp $
* $PostgreSQL: pgsql/src/backend/commands/copy.c,v 1.310 2009/06/03 14:48:33 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -175,7 +175,8 @@ typedef struct
/*
* These macros centralize code used to process line_buf and raw_buf buffers.
* They are macros because they often do continue/break control and to avoid
* function call overhead in tight COPY loops.
* function call overhead in tight COPY loops. "((void) 0)" is used to silence
* compiler warnings.
*
* We must use "if (1)" because "do {} while(0)" overrides the continue/break
* processing. See http://www.cit.gu.edu.au/~anthony/info/C/C.macros.