33 Thread support library [thread]

33.4 Mutual exclusion [thread.mutex]

33.4.3 Mutex requirements [thread.mutex.requirements]

33.4.3.1 In general [thread.mutex.requirements.general]

A mutex object facilitates protection against data races and allows safe synchronization of data between execution agents.
An execution agent owns a mutex from the time it successfully calls one of the lock functions until it calls unlock.
Mutexes can be either recursive or non-recursive, and can grant simultaneous ownership to one or many execution agents.
Both recursive and non-recursive mutexes are supplied.