30 Thread support library [thread]

30.4 Mutual exclusion [thread.mutex]

30.4.2 Locks [thread.lock]

30.4.2.2 Class template unique_lock [thread.lock.unique]

30.4.2.2.1 unique_lock constructors, destructor, and assignment [thread.lock.unique.cons]

unique_lock() noexcept;

Effects: Constructs an object of type unique_lock.

Postconditions: pm == 0 and owns == false.

explicit unique_lock(mutex_type& m);

Requires: If mutex_type is not a recursive mutex the calling thread does not own the mutex.

Effects: Constructs an object of type unique_lock and calls m.lock().

Postconditions: pm == &m and owns == true.

unique_lock(mutex_type& m, defer_lock_t) noexcept;

Effects: Constructs an object of type unique_lock.

Postconditions: pm == &m and owns == false.

unique_lock(mutex_type& m, try_to_lock_t);

Requires: The supplied Mutex type shall meet the Lockable requirements ([thread.req.lockable.req]). If mutex_type is not a recursive mutex the calling thread does not own the mutex.

Effects: Constructs an object of type unique_lock and calls m.try_lock().

Postconditions: pm == &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);

Requires: The calling thread own the mutex.

Effects: Constructs an object of type unique_lock.

Postconditions: pm == &m and owns == true.

Throws: Nothing.

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

Requires: If mutex_type is not a recursive mutex the calling thread does not own the mutex. The supplied Mutex type shall meet the TimedLockable requirements ([thread.req.lockable.timed]).

Effects: Constructs an object of type unique_lock and calls m.try_lock_until(abs_time).

Postconditions: pm == &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);

Requires: If mutex_type is not a recursive mutex the calling thread does not own the mutex. The supplied Mutex type shall meet the TimedLockable requirements ([thread.req.lockable.timed]).

Effects: Constructs an object of type unique_lock and calls m.try_lock_for(rel_time).

Postconditions: pm == &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;

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

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.

Note: With a recursive mutex it is possible for both *this and u to own the same mutex before the assignment. In this case, *this will own the mutex after the assignment and u will not.  — end note ]

~unique_lock();

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