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 // template <class Mutex> 17 // void swap(shared_lock<Mutex>& x, shared_lock<Mutex>& y) noexcept; 18 19 #include <shared_mutex> 20 #include <cassert> 21 22 #if _LIBCPP_STD_VER > 11 23 24 struct mutex 25 { 26 void lock_shared() {} 27 void unlock_shared() {} 28 }; 29 30 mutex m; 31 32 #endif // _LIBCPP_STD_VER > 11 33 34 int main() 35 { 36 #if _LIBCPP_STD_VER > 11 37 std::shared_lock<mutex> lk1(m); 38 std::shared_lock<mutex> lk2; 39 swap(lk1, lk2); 40 assert(lk1.mutex() == nullptr); 41 assert(lk1.owns_lock() == false); 42 assert(lk2.mutex() == &m); 43 assert(lk2.owns_lock() == true); 44 static_assert(noexcept(swap(lk1, lk2)), "non-member swap must be noexcept"); 45 #endif // _LIBCPP_STD_VER > 11 46 } 47
