Is there a shorthand for std::lock_guard lock(m)?

For pre-C++17:

template<class Mutex>
std::lock_guard<Mutex> make_lock_guard(Mutex& mutex) {
    mutex.lock();
    return { mutex, std::adopt_lock };
}

Use as:

std::mutex someMutex;
auto&& lg = make_lock_guard(someMutex);

This takes advantage of the fact that copy-list-initialization doesn’t create an additional temporary (even conceptually). The one-parameter constructor is explicit and can’t be used for copy-list-initialization, so we lock the mutex first and then use the std::adopt_lock constructor.

The return value is then directly bound to lg, which extends its lifetime to that of the reference, once again creating no temporary (even conceptually) in the process.