Am Thu, 20 Sep 2012 10:11:37 +0200 schrieb "Namespace" <rswhi...@googlemail.com>:
> You're right. > This is my next try: http://dpaste.dzfl.pl/02b32d33 > Do you have anything else to say? :) I think it shouldn't be possible to copy an OnStack struct. The destructor is run for every copy, but the constructor was run only once. So if a class keeps external references (e.g. file handles) and closes those handles in the destructor, making a copy would result in the destructor running twice and therefore closing the same handle twice. I think the usage of a OnStack struct must be quite limited to be safe: { auto a = OnStack!(A)(); //allocate in scope a.doSomething(); //Calling members is fine //a.get and a must not escape this scope (I guess we can't guarantee //that without compiler help?) //passing a.get to a function is valid, as long as the function //doesn't keep a reference (the function parameter must be marked //with scope) someMethod(a.get); //As a shouldn't be copied, an OnStack can't be passed to another //function. //no copies for OnStack allowed //destroy at end of scope } Those rules are pretty strict, but maybe that's the only way to have a safe OnStack. Maybe I forgot some detail and those rules aren't even strict enough.
