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// UNSUPPORTED: c++03, c++98, c++11, c++14 12 13// <shared_mutex> 14 15// class shared_mutex; 16 17// bool try_lock(); 18 19#include <shared_mutex> 20#include <thread> 21#include <cstdlib> 22#include <cassert> 23 24std::shared_mutex m; 25 26typedef std::chrono::system_clock Clock; 27typedef Clock::time_point time_point; 28typedef Clock::duration duration; 29typedef std::chrono::milliseconds ms; 30typedef std::chrono::nanoseconds ns; 31 32void f() 33{ 34 time_point t0 = Clock::now(); 35 assert(!m.try_lock()); 36 assert(!m.try_lock()); 37 assert(!m.try_lock()); 38 while(!m.try_lock()) 39 ; 40 time_point t1 = Clock::now(); 41 m.unlock(); 42 ns d = t1 - t0 - ms(250); 43 assert(d < ms(200)); // within 200ms 44} 45 46int main() 47{ 48 m.lock(); 49 std::thread t(f); 50 std::this_thread::sleep_for(ms(250)); 51 m.unlock(); 52 t.join(); 53} 54