"Jean Delvare" <[email protected]> said:
[Sttributions missing, sorry]
> > > Think about it. If the pointer could be NULL, then it's unlikely that
> > > the bug would have gone unnoticed so far (unless the code is very
> > > recent). Coverity found 3 such bugs in one i2c driver [1], and the
> > > correct solution was to NOT check for NULL because it just couldn't
> > > happen.
> > No, there is a third case: the pointer can be NULL, but the compiler
> > happened to move the dereference down to after the check.
> Wow. Great point. I completely missed that possibility. In fact I didn't
> know that the compiler could possibly alter the order of the
> instructions. For one thing, I thought it was simply not allowed to. For
> another, I didn't know that it had been made so aware that it could
> actually figure out how to do this kind of things. What a mess. Let's
> just hope that the gcc folks know their business :)
The compiler is most definitely /not/ allowed to change the results the
code gives.
--
Dr. Horst H. von Brand User #22616 counter.li.org
Departamento de Informatica Fono: +56 32 654431
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Casilla 110-V, Valparaiso, Chile Fax: +56 32 797513
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