Re: [boost] [Range] initial feedback on return values of algorithms

From: David Abrahams (dave_at_[hidden])
Date: 2006-02-04 23:22:13

Thorsten Ottosen <tottosen_at_[hidden]> writes:

>> No, that's not the same thing at all.  Read what I wrote again.
>
> ok, so we could return a tripple {begin,found,end}.

I said quadruple.  I meant {begin,found,found+1,end}.

> this means that
>
> 1. we loose the benefit of a default

The default might be a different function.  In fact it would be in
your case, too, since you can't deduce an explicit template argument
from a default value.

> 2. a slight overhead (the tripple construction cannot be optmized away)

How do you know?

The compiler can optimize anything it wants as long as it doesn't
change the observable behavior.

> 3. at least as complicated an implementation

Maybe.

> I couldn't find the definition of "temporary" in the standard; is it 
> defined and inherted from C?

It's not explicitly defined anywhere.  The standard describes
situations in which a "temporary object" or "temporary" is created and
then has special rules for what can be done with such an object.

>> Sounds easy enough to do without a switch.  And anyway, who cares
>> about such a tiny implementation detail?
>
> nobody unless it affects the generated code size/speed.

Right.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com