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From: chris@umcp-cs.UUCP (Chris Torek)
Newsgroups: net.lang.c
Subject: Re: Indirect comma assigned from side effects
Message-ID: <3133@umcp-cs.UUCP>
Date: Tue, 26-Aug-86 09:42:37 EDT
Article-I.D.: umcp-cs.3133
Posted: Tue Aug 26 09:42:37 1986
Date-Received: Wed, 27-Aug-86 09:16:57 EDT
References: <792@navajo.STANFORD.EDU> <3047@umcp-cs.UUCP> <796@navajo.STANFORD.EDU> <2401@ihlpg.UUCP>
Reply-To: chris@umcp-cs.UUCP (Chris Torek)
Organization: University of Maryland, Dept. of Computer Sci.
Lines: 22

>>>	foo() { *( index=lhs, pointers[index] ) = sideeffects(); }
>>>... does C allow for the possibility that the order
>>>of evaluation might be "index=lhs" then "sideeffects()" then
>>>"*pointers[index]=<result>"?

>In article <3047@umcp-cs.UUCP> I wrote:
>>No.

In article <2401@ihlpg.UUCP> tainter@ihlpg.UUCP (Tainter) writes:
>As far as I can tell the only restriction on order of evaluation is 
>index=lhs before pointers[index].

After more thought, I now reverse myself.  K&R (p. 192) say only
`a pair of expressions separated by a comma is evaluated left-to-
right and the value of the left expression is discarded.'  Apparently
this does not imply that nothing else may occur in between.  I may
see whether X3J11 is more explicit, but that must wait until I am
once again near a copy of the latest draft.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 1516)
UUCP:	seismo!umcp-cs!chris
CSNet:	chris@umcp-cs		ARPA:	chris@mimsy.umd.edu