# std::recursive_mutex::unlock

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< cpp‎ | thread‎ | recursive mutex

void unlock(); |  | (since C++11)

Unlocks the mutex if its level of ownership is 1 (there was exactly one more call to lock() than there were calls to `unlock()` made by this thread), reduces the level of ownership by 1 otherwise.

The mutex must be locked by the current thread of execution, otherwise, the behavior is undefined.

This operation synchronizes-with (as defined in std::memory_order) any subsequent lock operation that obtains ownership of the same mutex.

### Parameters

(none)

### Return value

(none)

### Exceptions

Throws nothing.

### Notes

`unlock()` is usually not called directly: std::unique_lock and std::lock_guard are used to manage exclusive locking.

### Example

| This section is incomplete Reason: no example

### See also

lock | locks the mutex, blocks if the mutex is not available (public member function)
try_lock | tries to lock the mutex, returns if the mutex is not available (public member function)

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