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From: madd@world.std.com (jim frost)
Newsgroups: comp.lang.c,alt.folklore.computers
Subject: Re: Beautiful side-effects! (q = q++)
Message-ID: <1991Jun29.180635.19115@world.std.com>
Date: 29 Jun 91 18:06:35 GMT
References: <15520@exodus.Eng.Sun.COM> <1991Jun25.151408.1024@ux1.cso.uiuc.edu> <1991Jun26.154734.14439@dsuvax.uucp> <1991Jun27.163643.1223@tc.fluke.COM>
Organization: The World @ Software Tool & Die
Lines: 16

kurt@tc.fluke.COM (Kurt Guntheroth) writes:
>> "q = q++;" SHOULD leave q unchanged

>K&R says nothing about when the increment's side effect is processed, and
>ANSI says specifically that it is undefined.

Both K&R 1 and 2 say that the behavior is undefined (p 50 and 53-54
respectively, I know 'em by heart) as does ANSI.

With respect to the gcc versus vcc code difference: note that gcc
produced more efficient code by evaluating in a different order.  This
is precisely the reason K&R give for leaving the order undefined.

Happy hacking,

jim