The mutexes and locks here have simple interfaces that are designed for high performance. The interfaces enforce the scoped locking pattern, which is widely used in C++ libraries because:

There are two parts to the pattern: a mutex and a lock. The constructor of the lock object acquires the lock, and the destructor of the lock object releases the lock. Here’s an example:

	{
	    // Construction of myLock acquires lock on myMutex
	    M::scoped_lock myLock( myMutex );
	    ... actions to be performed while holding the lock ...
	    // Destruction of myLock releases lock on myMutex
	}

If the actions throw an exception, the lock is automatically released as the block is exited.

Table 7-2 summarizes the classes that model the Mutex Concept.