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From: andy@rocky.STANFORD.EDU (Andy Freeman)
Newsgroups: comp.lang.c
Subject: typeof isn't enough to define swap correctly
Message-ID: <557@rocky.STANFORD.EDU>
Date: Fri, 4-Sep-87 14:36:13 EDT
Article-I.D.: rocky.557
Posted: Fri Sep  4 14:36:13 1987
Date-Received: Sat, 5-Sep-87 18:35:55 EDT
Reply-To: andy@rocky.UUCP (Andy Freeman)
Organization: Stanford University Computer Science Department
Lines: 19

In article <1354@dataio.Data-IO.COM>, bright@dataio.Data-IO.COM (Walter Bright) writes:
> ... One thing I want, which the committee always seems to poo-poo, is a
> typeof. Having a typeof would make creation of 'generic' routines possible:

> 	#define swap(a,b)	{ typeof(a) tmp; tmp = a; a = b; b = tmp; }

Even given typeof, this definition of swap is buggy.  (It has at least
two bugs.)  I've never figured out how to define a C swap macro that
works - I'm willing to believe it is impossible.

Anyone have a use for typeof that isn't doesn't have the major bug that
the swap macro defined above has?

-andy
-- 
Andy Freeman
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