David Abrahams wrote:
"Neal D. Becker" <nbecker@hns.com> writes:
This handy little item, lvalue_cast, would make a useful addition to boost. I didn't write it, and I don't recall who did.
The problem with that is that casting away the const on a const rvalue is sometimes unsafe. See the original move semantics proposal for details.
Not sure what you're saying here. I agree it can sometimes be unsafe. That's why you shouldn't use it - except when you really want to. Isn't that consistent with the move semantics proposal? The main use I had in mind, is when you want: void F (T1 in, T2 &out) { write to out } F (something, make_temp()) Where you don't really care that F is going to write to the temporary, it's really not used. Other approaches are possible here, e.g., boost::optional - but this was intended for the case where F was already written to a certain interface.