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Path: utzoo!mnetor!seismo!rutgers!ames!hc!hi!josh
From: josh@hi.uucp (Josh Siegel )
Newsgroups: comp.lang.c
Subject: Stupid evaluation ordering.  Is this legal?
Message-ID: <4395@hi.uucp>
Date: Fri, 17-Apr-87 17:45:31 EST
Article-I.D.: hi.4395
Posted: Fri Apr 17 17:45:31 1987
Date-Received: Sun, 19-Apr-87 13:12:56 EST
Organization: Univ. of New Mexico, Albuquerque
Lines: 36
Keywords: K&R, Bible, PCs, UNIX

I just lost a argument and am running to the net for comfort...

According to K&R(Bible) page 185,  a C compiler is allowed to do the
 following.  

Given:

	a(b()+c(),d()+e())

	It is allowed to run functions b() and d(), then run
	c() and e(), THEN add them (This has shades of
	compilers that optimise on parallel machines).  
	This causes problems with stuff like:

.
.
.
	struct foobar *getit();

	doit(getit(5)->foo1, getit(7)->foo5)
.
.
.
When getit() returns a pointer to a internal static buffer.

Should it be allowed to do this?  yes yes.. I know I should
 just use a temp var but thats not the point!  Whine!!!

			
	Sigh...


-- 
Josh Siegel		(siegel@hc.dspo.gov)
                        (505) 277-2497  (Home)
		I'm a mathematician, not a programmer!