4.2 KiB
[thread.lock.shared.general]
32 Concurrency support library [thread]
32.6 Mutual exclusion [thread.mutex]
32.6.5 Locks [thread.lock]
32.6.5.5 Class template shared_lock [thread.lock.shared]
32.6.5.5.1 General [thread.lock.shared.general]
namespace std {templateclass shared_lock {public:using mutex_type = Mutex; // [thread.lock.shared.cons], construct/copy/destroy shared_lock() noexcept; explicit shared_lock(mutex_type& m); // blocking shared_lock(mutex_type& m, defer_lock_t) noexcept; shared_lock(mutex_type& m, try_to_lock_t); shared_lock(mutex_type& m, adopt_lock_t); template<class Clock, class Duration> shared_lock(mutex_type& m, const chrono::time_point<Clock, Duration>& abs_time); template<class Rep, class Period> shared_lock(mutex_type& m, const chrono::duration<Rep, Period>& rel_time); ~shared_lock();
shared_lock(const shared_lock&) = delete; shared_lock& operator=(const shared_lock&) = delete;
shared_lock(shared_lock&& u) noexcept; shared_lock& operator=(shared_lock&& u) noexcept; // [thread.lock.shared.locking], lockingvoid lock(); // blockingbool try_lock(); template<class Rep, class Period>bool try_lock_for(const chrono::duration<Rep, Period>& rel_time); template<class Clock, class Duration>bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time); void unlock(); // [thread.lock.shared.mod], modifiersvoid swap(shared_lock& u) noexcept; mutex_type* release() noexcept; // [thread.lock.shared.obs], observersbool owns_lock() const noexcept; explicit operator bool() const noexcept; mutex_type* mutex() const noexcept; private: mutex_type* pm; // exposition onlybool owns; // exposition only};}
An object of type shared_lock controls the shared ownership of a lockable object within a scope.
Shared ownership of the lockable object may be acquired at construction or after construction, and may be transferred, after acquisition, to another shared_lock object.
Objects of typeshared_lock are not copyable but are movable.
The behavior of a program is undefined if the contained pointer pm is not null and the lockable object pointed to by pm does not exist for the entire remaining lifetime ([basic.life]) of the shared_lock object.
The suppliedMutex type shall meet the Cpp17SharedLockable requirements ([thread.req.lockable.shared]).
[Note 1:
shared_lock meets the Cpp17Lockable requirements ([thread.req.lockable.req]).
If Mutex meets the Cpp17SharedTimedLockable requirements ([thread.req.lockable.shared.timed]),shared_lock also meets the Cpp17TimedLockable requirements ([thread.req.lockable.timed]).
â end note]