Acquire a lock on two mutexes and avoid deadlock

Question

The following code contains a potential deadlock, but seems to be necessary: to safely copy data to one container from another, both containers must be locked to prevent cha

Answer 1

this is a known problem already there is a std solution. std::lock() can be called on 2 or more mutex at the same time whilst avoiding deadlock's. More information here it does offer a recommendation.

std::scoped_lock offers a RAII wrapper for this function, and is generally preferred to a naked call to std::lock.

of course this doesn't really allow early releases of one lock above the other so use std::defer_lock or std::adopt_lock like I did in this answer to a similar question.