33 Concurrency support library [thread]

33.6 Mutual exclusion [thread.mutex]

33.6.5 Locks [thread.lock]

33.6.5.5 Class template shared_­lock [thread.lock.shared]

33.6.5.5.5 Observers [thread.lock.shared.obs]

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