Re: 'C' Operators precedence

H. Peter Anvin (hpa@transmeta.com)
20 May 1998 06:37:11 GMT

Followup to: <19980519231814.17554@molehill.org>
By author: Todd Larason <jtl@molehill.org>
In newsgroup: linux.dev.kernel
>
> > (a=0)+a+(a=1) could evaluate in any of a number of ways, and leave a equal
> > to 0 or 1 afterwards.
>
> Or anything else. Or ignore a completely and go wash your dog. This
> modifies 'a' more than once between sequence points, and is completely
> undefined behavior. (on the quality-of-implementation issue, it would be
> nice if there were some high quality compilers that WOULD go wash your dog
> in this case.)
>

There is an unconfirmed story that a certain version of gcc, if you
invoked some particular kind of undefined behaviour that RMS didn't
approve of (#pragma, I believe), gcc would look for and exec a copy of
nethack.

-hpa

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