# std::condition_variable_any

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Defined in header `<condition_variable>` |  |
class condition_variable_any; |  | (since C++11)

The `condition_variable_any` class is a generalization of std::condition_variable. Whereas std::condition_variable works only on std::unique_lock<std::mutex>, `condition_variable_any` can operate on any lock that meets the BasicLockable requirements.

See std::condition_variable for the description of the semantics of condition variables.

The class `std::condition_variable_any` is a StandardLayoutType. It is not CopyConstructible, MoveConstructible, CopyAssignable, or MoveAssignable.

If the lock is std::unique_lock, std::condition_variable may provide better performance.

### Member functions

(constructor) | constructs the object (public member function)
(destructor) | destructs the object (public member function)
operator= [deleted] | not copy-assignable (public member function)

##### Notification

notify_one | notifies one waiting thread (public member function)
notify_all | notifies all waiting threads (public member function)

##### Waiting

wait | blocks the current thread until the condition variable is woken up (public member function)
wait_for | blocks the current thread until the condition variable is woken up or after the specified timeout duration (public member function)
wait_until | blocks the current thread until the condition variable is woken up or until specified time point has been reached (public member function)

### Notes

`std::condition_variable_any` can be used with std::shared_lock in order to wait on a std::shared_mutex in shared ownership mode.

A possible use for `std::condition_variable_any` with custom Lockable types is to provide convenient interruptible waits: the custom lock operation would both lock the associated mutex as expected, and also perform the necessary setup to notify this condition variable when the interrupting signal is received.[1]

### References

1. ↑ A. Williams (2012), "C++ concurrency in action" 9.2.4 Interrupting a wait on std::condition_variable_any

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