RE: [boost] Re: Optimising assignment using std::swap

From: Moore, Paul (paul.moore_at_[hidden])
Date: 2001-01-22 05:19:08

From: Dean Sturtevant [mailto:deansturtevant_at_[hidden]]
> I find it hard to imagine a case where std::swap is more efficient 
> than assignment, unless the assignment is coded inefficiently. Can 
> you provide an example where that might not be the case?

My thought was a long-integer type where the internal representation was a
(potentially) large array of "digits". The swap operation could be a simple
pointer exchange, whereas assignment would need allocation and copying of a
new digit array. (Assuming reference counting isn't used, possibly for
thread-safety reasons).

It seems fairly likely that this would be the case.

Paul.