Re: oops? read/write vs type of length parameter

[Eli Zaretskii <eliz@gnu.org>]

> From: Jim Meyering <jim@meyering.net>
> Cc: emacs-devel@gnu.org
> Date: Mon, 11 Apr 2011 14:27:36 +0200
> 
> > That would be a major inconvenience, and even annoyance: in Emacs, it
> > is a very frequent idiom to pass the result of subtracting two
> > EMACS_INT values, because we reference buffers and strings with such
> > values.  Having the argument as unsigned type would trigger warnings
> > and will need explicit type casts.  And with type casts, there's the
> > danger of interpreting a negative value as a large positive one.
> 
> >From my experience with signedness-related warnings,
> it is counterproductive to enable options like -Wsign-conversion
> and -Wsign-compare, unless you're prepared to cherry-pick fixes for
> the few "real" problems and to ignore the others.

I agree, but unfortunately -Wall includes warnings about signedness,
and I sometimes use -Wall to make sure I didn't miss something
potentially bad.  And there's no way of knowing what some future
version of GCC will do to save us from ourselves ;-)

> Adding casts to work around them makes the "cure" worse than the
> disease.

Right, which is why I didn't want to use them.

> What about when EMACS_INT is defined to "int"?

David answered that: the result would be less grave than the other way
around.