[Cryptography] GCC bug 30475 (was Re: bounded pointers in C)

[Viktor Dukhovni]

On Thu, Apr 24, 2014 at 05:04:14PM -0700, Bear wrote:

> There are in fact conformant checks for signed overflow. 
> 
> For example, you can say 
> 
> if (MAXINT - al >= be) halt(2); // overflow check - not using assert()
>                                 // because we want this check in
>                                 // production code.
> ce = al + be;                   // addition guaranteed not to overflow.

That's nice, but how do I do that for an "off_t", or other typedefed
integral type, which has no explicit INTFOO_MAX macro?

Ideally something that does not introduce a C99 dependency and
works even with older ANSI C compilers.

-- 
	Viktor.