Re: asm/unistd.h

[Andreas Schwab <schwab@suse.de>]

Joseph Carter <knghtbrd@debian.org> writes:

|> On Thu, Apr 05, 2001 at 09:06:20AM -0400, Bart Trojanowski wrote:
|> > So you ask: "why not just use a { ... } to define a macro".  I don't
|> > remember the case for this but I know it's there.  It has to do with a
|> > complicated if/else structure where a simple {} breaks.
|> 
|> This doesn't follow in my mind.  I can't think of a case where a { ... }
|> would fail, but a do { ... } while (0) would succeed.  The former would
|> also save a few keystrokes.

Try this and watch your compiler complaining:

#define foo() { }
#define bar() do { } while (0)
void mumble ()
{
        if (1) foo(); else bar();
        if (2) bar(); else foo();
}

Andreas.

-- 
Andreas Schwab                                  "And now for something
SuSE Labs                                        completely different."
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