Path: utzoo!utgpu!watserv1!watmath!att!tut.cis.ohio-state.edu!cs.utexas.edu!uunet!sdrc!thor!scjones
From: scjones@thor.UUCP (Larry Jones)
Newsgroups: comp.lang.c
Subject: Re: &&**
Message-ID: <165@thor.UUCP>
Date: 10 Sep 90 13:00:31 GMT
References: <1990Sep7.021321.18381@watmath.waterloo.edu> <0926@sheol.UUCP>
Organization: SDRC, Cincinnati
Lines: 20

In article <0926@sheol.UUCP>, throopw@sheol.UUCP (Wayne Throop) writes:
> [ about compilers allowing "&(&(&(***x)))" ]
> This is apparently a VERY common bug.  It shakes my faith in
> the competence of C implementors.  Unless I'm missing something
> quite major...???

It's a very easy mistake to make.  Since both &* and *& are
essentially noops, most compilers will remove adjacent pairs
as part of the optimization of expression trees.  Since tree
rewriting is generally iterative, this results in all such
pairs being removed.  Semantic restrictions (like lvalueness)
are generally not tested until after rewriting, so bogus code
like this slips through.
----
Larry Jones                         UUCP: uunet!sdrc!thor!scjones
SDRC                                      scjones@thor.UUCP
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