First introduced in the 2017 standard, the scoped lock is a mutex wrapper which obtains access to (locks) the provided mutex, and ensures it is unlocked when the scoped lock goes out of scope. It differs from a lock guard in that it is a wrapper for not one, but multiple mutexes.

This can be useful when one deals with multiple mutexes in a single scope. One reason to use a scoped lock is to avoid accidentally introducing deadlocks and other unpleasant complications with, for example, one mutex being locked by the scoped lock, another lock still being waited upon, and another thread instance having the exactly opposite situation.

One property of a scoped lock is that it tries to avoid such a situation, theoretically making this type of lock deadlock-safe.