In C++ this can be done by having functions that need to be called with the lock held, but won't take the lock themselves, take the lock guard as a parameter.

In C++ this can be done by having functions that need to be called with the lock held, but won't take the lock themselves, take the lock guard as a parameter. There are also patterns like the synchronized wrapper were the lock is bolted on transparently and all the functions in a class can call each other without worrying about the lock.