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From: chris@umcp-cs.UUCP (Chris Torek)
Newsgroups: net.lang.c
Subject: Re: C pre-processor and ANSI standard
Message-ID: <8214@umcp-cs.UUCP>
Date: Sun, 9-Sep-84 18:46:15 EDT
Article-I.D.: umcp-cs.8214
Posted: Sun Sep  9 18:46:15 1984
Date-Received: Fri, 14-Sep-84 08:25:01 EDT
References: <572@calgary.UUCP>
Organization: U of Maryland, Computer Science Dept., College Park, MD
Lines: 37

I always parenthesize my min/max #define's.  The big problem with those
is that they still generate side effects twice.  (But hey!, that's what
macros are all about!)

As for a macro to put out N spaces, how about:

#define spaces(n) \
	if (1) { \
		register int _youwouldntusethisid = (n); \
		while (--_youwouldntusethisid >= 0) \
			putchar(' '); \
	} \
	else

This gets around the

	if (expr)
		spaces(expr);
	else
		...

(dangling else) problem.  Now your only trap is writing

	foo()
	{
		spaces(6)
		bar();
	}

(a missing semicolon makes unreachable code).

Unfortunately, this gives lint indigestion (``constant in conditional
context'').
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci (301) 454-7690
UUCP:	{seismo,allegra,brl-bmd}!umcp-cs!chris
CSNet:	chris@umcp-cs		ARPA:	chris@maryland