33 Concurrency support library [thread]

33.6 Mutual exclusion [thread.mutex]

33.6.4 Mutex requirements [thread.mutex.requirements] Timed mutex types [thread.timedmutex.requirements] Class recursive_timed_mutex [thread.timedmutex.recursive]

namespace std { class recursive_timed_mutex { public: recursive_timed_mutex(); ~recursive_timed_mutex(); recursive_timed_mutex(const recursive_timed_mutex&) = delete; recursive_timed_mutex& operator=(const recursive_timed_mutex&) = delete; void lock(); // blocking bool try_lock() noexcept; 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(); using native_handle_type = implementation-defined; // see [thread.req.native] native_handle_type native_handle(); // see [thread.req.native] }; }
The class recursive_timed_mutex provides a recursive mutex with exclusive ownership semantics.
If one thread owns a recursive_timed_mutex object, attempts by another thread to acquire ownership of that object will fail (for try_lock()) or block (for lock(), try_lock_for(), and try_lock_until()) until the owning thread has completely released ownership or the call to try_lock_for() or try_lock_until() times out (having failed to obtain ownership).
The class recursive_timed_mutex meets all of the timed mutex requirements ([thread.timedmutex.requirements]).
It is a standard-layout class ([class.prop]).
A thread that owns a recursive_timed_mutex object may acquire additional levels of ownership by calling lock(), try_lock(), try_lock_for(), or try_lock_until() on that object.
It is unspecified how many levels of ownership may be acquired by a single thread.
If a thread has already acquired the maximum level of ownership for a recursive_timed_mutex object, additional calls to try_lock(), try_lock_for(), or try_lock_until() fail, and additional calls to lock() throw an exception of type system_error.
A thread shall call unlock() once for each level of ownership acquired by calls to lock(), try_lock(), try_lock_for(), and try_lock_until().
Only when all levels of ownership have been released may ownership of the object be acquired by another thread.
The behavior of a program is undefined if:
  • it destroys a recursive_timed_mutex object owned by any thread, or
  • a thread terminates while owning a recursive_timed_mutex object.