# queuing_mutex Class

## Summary

Class that models Mutex Concept that is fair and scalable.

## Syntax

    class queuing_mutex;

## Header

    #include "tbb/queuing_mutex.h"

## Description

A `queuing_mutex` models the Mutex Concept. A `queuing_mutex` is scalable, in the sense that if a thread has to wait to acquire the mutex, it spins on its own local cache line. A `queuing_mutex` is fair. Threads acquire a lock on a mutex in the order that they request it. A `queuing_mutex` is not recursive.

The current implementation does busy-waiting, so using a `queuing_mutex` may degrade system performance if the wait is long.

## Members

See Mutex Concept.

Parent topic: Mutexes

## See Also

Mutext Concept