Re: Change to catch unsafe use with exceptions.

Tiago wrote: I wouldn't go further to extend it. There's nothing that says that creating a pointer in one thread and using in another cannot be made safe.

That is true but it is made safe by using shared ownership. I don't think you can safely use a pointer to a unique_ptr controlled by another thread. If there is a way, tell me, and I'll do that instead of throwing an exception.

Tiago also wrote: Sometimes it's just better to do nothing and be aware of the limitations. If you are going to put further constraints, it will also less likely to be useful.

I think the question is should you burden correct use with thread checks just in case somebody has a go at incorrect use. Traditionally the answer would be no. You are paying for something that you don't intend to use – classify the incorrect use as ill formed code and leave it at that. However now that there is an existential imperative to make C++ safer, a different view might prevail. A smart pointer will be expected to do clever things and all of it safely, so allowing it to do unsafe things under the illusion of it being safe probably should be prevented.

The change is only three lines of code although it was a bit of a head bender figuring out how that makes it work. A compromise between the traditional view and the more modern safety imperative might be to have those lines conditionally compile just for Debug builds.

I think there has to be something to prevent you from writing code that looks good, compiles without warnings and appears to work but will go off the rails at some indeterminate point in the future. That is exactly the sort of thing that gives C++ a bad reputation.