[boost] Re: On bind::operator==, again

From: Howard Hinnant (hinnant_at_[hidden])
Date: 2004-03-11 17:52:44

On Mar 11, 2004, at 4:06 PM, Douglas Gregor wrote:

> On Thursday 11 March 2004 03:14 pm, David Abrahams wrote:
>> Just to throw more darts at the idea, building the composite function
>> object could be an expensive way to arrive at an immediate bool result
>> if copying the function objects was a nontrivial operation.
>
> Thoughout the STL is the implicit assumption that function objects are 
> cheap
> to copy. We're not making any new assumptions here.

Unfortunately I wouldn't classify function<...> as cheap to copy.  It's 
not terribly expensive either, but it does call new during the copy 
ctor (unless I'm just looking at a flawed implementation - my own ;-) 
).  But bind should be cheap to copy as long as its contained functors 
are cheap.

-Howard