[ccan] [PATCH] minmax: New module

[David Gibson]

On Mon, Jun 02, 2014 at 12:54:05PM +0930, Paul 'Rusty' Russell wrote:
> David Gibson <david at gibson.dropbear.id.au> writes:
> > Add a 'minmax' module with typesafe macros to compute minimum, maximum and
> > clamping.  Inspired by the versions used in the Linux kernel, but using
> > a different implementation based on __builtin_types_compatible_p() and the
> > cast module.
> 
> The reason I never implemented this is because I was worried about
> idempotency failure.  Your functions double-evaluate, which bad form
> even if they were named MIN and MAX and thus clearly macros.

Ah.  Excellent point.

> Unfortunately it's not possible to create an idempotent min or max
> without gcc extensions which operates on 64 bit types (or whatever the
> largest integer type is).
> 
> It wouldn't be the first module which had preconditions, however:
> we could create a module which simply doesn't compile if you don't have
> statement expressions.

Ok, new version coming, requiring statement expressions and typeof.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson
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