"Gennadiy Rozental" <gennadiy.rozental@thomson.com> writes:
And dangerous. Cause allows developer to "forget" about an extra copy.
I'm not sure where you think the "extra" copy is. The copy is already implicit in the RHS expression, isn't it?
No. In this case we could control the copy.
collection foo();
returns temporary. FOREACH make copy of this temporary into another temporary.
Are you sure that copy can't be elided?
This is an extra copy. Which we could easily control/eliminate with
collection const& c = foo();
statement.
In general C++ will make lots of copies you can't control. Extra copies are hardly "dangerous" (except maybe with auto_ptr). They may be inefficient, but then I don't believe in trying to prevent people from writing inefficient code, especially when that's more convenient. Very little of the code end users write actually needs to be fast.
That's true. But danger in this case caused by the fact that FOREACH make an extra copy silently.
Not danger; inefficiency.
Ok. I agree to keep this functionality. But there should be a bug disclaimer about this overhead.
Not bug... I don't know what. -- Dave Abrahams Boost Consulting www.boost-consulting.com