Mutex

A MUTEX is a mutual exclusion algorithms used in concurrent programming to avoid the simultaneous use of a common resource, such as a global variable, by pieces of computer code called critical sections.

Examples of such resources are flags, counters or queues, used to communicate between code that runs concurrently, such as an application and its interrupt handlers. The problem is acute because a thread can be stopped or started at any time.

A mutex is also a common name for a program object that negotiates mutual exclusion among threads, also called a lock.