33 Thread support library [thread]

33.4 Mutual exclusion [thread.mutex]

33.4.3 Mutex requirements [thread.mutex.requirements] Shared mutex types [thread.sharedmutex.requirements] Class shared_mutex [thread.sharedmutex.class]

namespace std {
  class 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]
The class shared_­mutex provides a non-recursive mutex with shared ownership semantics.
The class shared_­mutex shall satisfy all of the shared mutex requirements.
It shall be a standard-layout class (Clause [class]).
The behavior of a program is undefined if:
  • it destroys a shared_­mutex object owned by any thread,
  • a thread attempts to recursively gain any ownership of a shared_­mutex, or
  • a thread terminates while possessing any ownership of a shared_­mutex.
shared_­mutex may be a synonym for shared_­timed_­mutex.