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 // <shared_mutex> 11 12 // template <class Mutex> class shared_lock; 13 14 // template <class Mutex> 15 // void swap(shared_lock<Mutex>& x, shared_lock<Mutex>& y) noexcept; 16 17 #include <shared_mutex> 18 #include <cassert> 19 20 #if _LIBCPP_STD_VER > 11 21 22 struct mutex 23 { 24 void lock_shared() {} 25 void unlock_shared() {} 26 }; 27 28 mutex m; 29 30 #endif // _LIBCPP_STD_VER > 11 31 32 int main() 33 { 34 #if _LIBCPP_STD_VER > 11 35 std::shared_lock<mutex> lk1(m); 36 std::shared_lock<mutex> lk2; 37 swap(lk1, lk2); 38 assert(lk1.mutex() == nullptr); 39 assert(lk1.owns_lock() == false); 40 assert(lk2.mutex() == &m); 41 assert(lk2.owns_lock() == true); 42 static_assert(noexcept(swap(lk1, lk2)), "non-member swap must be noexcept"); 43 #endif // _LIBCPP_STD_VER > 11 44 } 45
