[thread.mutex.recursive] (original) (raw)

32 Concurrency support library [thread]

32.6 Mutual exclusion [thread.mutex]

32.6.4 Mutex requirements [thread.mutex.requirements]

32.6.4.2 Mutex types [thread.mutex.requirements.mutex]

32.6.4.2.3 Class recursive_mutex [thread.mutex.recursive]

namespace std { class recursive_mutex { public: recursive_mutex();~recursive_mutex(); recursive_mutex(const recursive_mutex&) = delete; recursive_mutex& operator=(const recursive_mutex&) = delete;void lock();bool try_lock() noexcept;void unlock();using native_handle_type = implementation-defined; native_handle_type native_handle(); };}

The class recursive_mutex provides a recursive mutex with exclusive ownership semantics.

If one thread owns a recursive_mutex object, attempts by another thread to acquire ownership of that object will fail (for try_lock()) or block (for lock()) until the first thread has completely released ownership.

A thread that owns a recursive_mutex object may acquire additional levels of ownership by calling lock() or try_lock() 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_mutexobject, additional calls to try_lock() fail, and additional calls tolock() throw an exception of type system_error.

A thread shall call unlock() once for each level of ownership acquired by calls tolock() and try_lock().

Only when all levels of ownership have been released may ownership be acquired by another thread.

The behavior of a program is undefined if