1 //===----------------------------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // UNSUPPORTED: libcpp-has-no-threads 11 12 // <shared_mutex> 13 14 // template <class Mutex> class shared_lock; 15 16 // void swap(shared_lock& u) noexcept; 17 18 #include <shared_mutex> 19 #include <cassert> 20 21 #if _LIBCPP_STD_VER > 11 22 23 struct mutex 24 { lock_sharedmutex25 void lock_shared() {} unlock_sharedmutex26 void unlock_shared() {} 27 }; 28 29 mutex m; 30 31 #endif // _LIBCPP_STD_VER > 11 32 main()33int main() 34 { 35 #if _LIBCPP_STD_VER > 11 36 std::shared_lock<mutex> lk1(m); 37 std::shared_lock<mutex> lk2; 38 lk1.swap(lk2); 39 assert(lk1.mutex() == nullptr); 40 assert(lk1.owns_lock() == false); 41 assert(lk2.mutex() == &m); 42 assert(lk2.owns_lock() == true); 43 static_assert(noexcept(lk1.swap(lk2)), "member swap must be noexcept"); 44 #endif // _LIBCPP_STD_VER > 11 45 } 46