[thread.lock.unique.cons]

unique_lock() noexcept;

Postconditions: pm == nullptr and owns == false.

explicit unique_lock(mutex_type& m);

Postconditions: pm == addressof(m) and owns == true.

unique_lock(mutex_type& m, defer_lock_t) noexcept;

Postconditions: pm == addressof(m) and owns == false.

unique_lock(mutex_type& m, try_to_lock_t);

Preconditions: The supplied Mutex type meets the Cpp17Lockable requirements ([thread.req.lockable.req]).

Postconditions: pm == addressof(m) and owns == res, where res is the value returned by the call to m.try_lock().

unique_lock(mutex_type& m, adopt_lock_t);

Throws: Nothing.

template<class Clock, class Duration>
  unique_lock(mutex_type& m, const chrono::time_point<Clock, Duration>& abs_time);

Preconditions: The supplied Mutex type meets the Cpp17TimedLockable requirements ([thread.req.lockable.timed]).

Postconditions: pm == addressof(m) and owns == res, where res is the value returned by the call to m.try_lock_until(abs_time).

template<class Rep, class Period>
  unique_lock(mutex_type& m, const chrono::duration<Rep, Period>& rel_time);

Postconditions: pm == addressof(m) and owns == res, where res is the value returned by the call to m.try_lock_for(rel_time).

unique_lock(unique_lock&& u) noexcept;

Postconditions: pm == u_p.pm and owns == u_p.owns (where u_p is the state of u just prior to this construction), u.pm == 0 and u.owns == false.

unique_lock& operator=(unique_lock&& u) noexcept;

Returns: *this.

~unique_lock();

Effects: If owns calls pm->unlock().

32 Concurrency support library [thread]