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Re: Exploiting knowing sizes of string.


On Thu, 4 Jun 2015, Richard Earnshaw wrote:

> > Change that into
> > 
> > int foo(char *s)
> > {
> >   int l = strlen (s);
> >   char *p = memchr (s, 'a', l);
> >   return p+l;
> > }
> > 
> 
> Which is still meaningless if 'a' does not appear in s => when the
> result is NULL + l.
> 
> In fact, unless 'a' is the first character the result is possibly
> meaningless anyway, since you can't know that p+l doesn't point more
> than one beyond the end of the object.
> 
> Perhaps you just meant to return 'p'?

And if size_t is wider than int, this function truncates the length of the 
string, so still isn't particularly sensible even if returning p.

-- 
Joseph S. Myers
joseph@codesourcery.com


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