30 Thread support library [thread]

30.4 Mutual exclusion [thread.mutex]

30.4.3 Mutex requirements [thread.mutex.requirements]

30.4.3.4 Shared mutex types [thread.sharedmutex.requirements]

30.4.3.4.1 Class shared_­mutex [thread.sharedmutex.class]

namespace std {
  class shared_mutex {
  public:
    shared_mutex();
    ~shared_mutex();

    shared_mutex(const shared_mutex&) = delete;
    shared_mutex& operator=(const shared_mutex&) = delete;

    // exclusive ownership
    void lock();                // blocking
    bool try_lock();
    void unlock();

    // shared ownership
    void lock_shared();         // blocking
    bool try_lock_shared();
    void unlock_shared();

    using native_handle_type = implementation-defined;          // see [thread.req.native]
    native_handle_type native_handle();                         // see [thread.req.native]
  };
}
1
#
The class shared_­mutex provides a non-recursive mutex with shared ownership semantics.
2
#
The class shared_­mutex shall satisfy all of the shared mutex requirements.
It shall be a standard-layout class ([class]).
3
#
The behavior of a program is undefined if:
  • (3.1)
    it destroys a shared_­mutex object owned by any thread,
  • (3.2)
    a thread attempts to recursively gain any ownership of a shared_­mutex, or
  • (3.3)
    a thread terminates while possessing any ownership of a shared_­mutex.
4
#
shared_­mutex may be a synonym for shared_­timed_­mutex.