33 Concurrency support library [thread]

33.6 Mutual exclusion [thread.mutex]

33.6.5 Locks [thread.lock]

33.6.5.4 Class template unique_­lock [thread.lock.unique]

33.6.5.4.5 Observers [thread.lock.unique.obs]

bool owns_lock() const noexcept;
Returns: owns.
explicit operator bool() const noexcept;
Returns: owns.
mutex_type *mutex() const noexcept;
Returns: pm.