C++ itself doesn't have the owning mutex, but there is one in Boost for example.
The problem with an owning mutex in such a language is that you can (on purpose or by mistake) keep accessing the thing it owned after you've released the protecting mutex. Rust's Mutex<T> owns the T but it has the behaviour you want where if you tried to keep the access to T but give back the mutex that doesn't compile. "I tried to unlock the mutex but I still need it, d'oh".
And the same problem applies broadly, you should not share write access to things without an ordering guarantee, but it's hard to ensure that guarantee is followed in C++.
Exactly. This stuff has been known about for a long time. It was just kind of ignored and you kinda hoped your library might have something to deal with it (boost, win32, pthread, etc). Then each one acted differently on different platforms or with each other. Some of the std lib is starting to have things we need. But now I have to deal with things in the crt and stdlib that actively break multi threading. Mutexes, semaphores, flags, pulsing, etc is not exactly new patterns. Real mess and you have to understand it too deeply for it to be meaningful to more people. It is why things like promise/async/await are very popular with javascript and their libraries. As it looks like multithreaded programming with a decently clear interface as to what it is going on.
The problem with an owning mutex in such a language is that you can (on purpose or by mistake) keep accessing the thing it owned after you've released the protecting mutex. Rust's Mutex<T> owns the T but it has the behaviour you want where if you tried to keep the access to T but give back the mutex that doesn't compile. "I tried to unlock the mutex but I still need it, d'oh".
And the same problem applies broadly, you should not share write access to things without an ordering guarantee, but it's hard to ensure that guarantee is followed in C++.