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From: david@sun.com (``Bob'' is the gun and YOU are the bullet...)
Newsgroups: comp.lang.c
Subject: Re: Using macros as statements (Re: Typeof operator in C)
Message-ID: <130338@sun.Eng.Sun.COM>
Date: 16 Jan 90 22:52:22 GMT
References: <16678@megaron.cs.arizona.edu> <7106@tank.uchicago.edu> <-K016ODxds13@ficc.uu.net> <721@eedsp.eedsp.gatech.edu> <19840@watdragon.waterloo.edu>
Sender: david@sun.Eng.Sun.COM
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In article <19840@watdragon.waterloo.edu> smking@lion.waterloo.edu (Scott
M. King) writes:
>To make a macro behave exactly as a statement, replace the { and } in
>the macro definition with START_MACRO and END_MACRO:
>#define START_MACRO		do {
>#define END_MACRO		} while ( 0 )

Unfortunately this is not lint-compatible ("constant in conditional
context").  I use a slight variation:

#ifdef lint
int _ZERO_;
#else
#define	_ZERO_ 0
#endif

#define	_STMT(s)	do { s } while (_ZERO_)

#define	FOO(bar)	_STMT(if (bar) frob();)

-- 
David DiGiacomo, Sun Microsystems, Mt. View, CA  sun!david david@eng.sun.com