Re: [2.6 patch][1/3] ipc/ BUG -> BUG_ON conversions

[Matt Mackall]

On Sat, Aug 28, 2004 at 12:58:16PM -0700, Andrew Morton wrote:
> Adrian Bunk <bunk@xxxxxxxxx> wrote:
> >
> >  > Anything you put in BUG_ON() must *NOT* have side effects.
> >  >...
> > 
> >  I'd have said exactly the same some time ago, but I was convinced by 
> >  Arjan that if done correctly, a BUG_ON() with side effects is possible  
> >  with no extra cost even if you want to make BUG configurably do nothing.
> 
> Nevertheless, I think I'd prefer that we not move code which has
> side-effects into BUG_ONs.  For some reason it seems neater that way.
> 
> Plus one would like to be able to do
> 
> 	BUG_ON(strlen(str) > 22);
> 
> and have strlen() not be evaluated if BUG_ON is disabled.

Well, strlen doesn't actually have a side effect, so it could be
marked pure and then be optimized away.

I'll push configurable BUG_ON support from -tiny to you shortly so
this will stop being theoretical.

-- 
Mathematics is the supreme nostalgia of our time.
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