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From: andrews@calgary.UUCP (Keith Andrews)
Newsgroups: comp.sys.ibm.pc
Subject: Re: TC2.0 bugfree ?
Summary: Again, not a bug
Message-ID: <537@cs-spool.calgary.UUCP>
Date: 20 Jan 89 16:30:12 GMT
References: <3785@druwy.ATT.COM>
Organization: U. of Calgary, Calgary, Ab.
Lines: 36

In article <3785@druwy.ATT.COM>, rhm@druwy.ATT.COM (Roger Massey) writes:
> No bugs in TC2.0 ?
> 
> This small model C program :
> 
> sub( cp )
> unsigned char 	*cp;
> {
> 	int 	i;
> 
> 	i = (*cp++ << 8) + *cp++;
> }
> 
    *** Omitted code showing that "cp" gets incremented twice at end of
        generate code instead of after each reference ***
> 
> Roger Massey
> AT&T  Denver

Sorry, this isn't a bug.  The order of evaluation of the ++ operators in
an expression is not guaranteed.  As evidence, this is what lint has to
say about the above code fragment:

	Script started on Fri Jan 20 09:21:51 1989
	1: lint foo.c
	foo.c(6): warning: cp evaluation order undefined
	foo.c(6): warning: i set but not used in function sub
	sub defined( foo.c(3) ), but never used
	2: ^D
	script done on Fri Jan 20 09:22:04 1989

Nevertheless, Turbo C likes to make noises about practically everything else,
I wonder they don't issue warnings about this?

					Keith Andrews
					andrews@cpsc.UCalgary.CA