1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // UNSUPPORTED: libcpp-has-no-threads 10 // 11 // ALLOW_RETRIES: 2 12 13 // <mutex> 14 15 // class mutex; 16 17 // bool try_lock(); 18 19 #include <mutex> 20 #include <thread> 21 #include <cstdlib> 22 #include <cassert> 23 24 #include "make_test_thread.h" 25 #include "test_macros.h" 26 27 std::mutex m; 28 29 typedef std::chrono::system_clock Clock; 30 typedef Clock::time_point time_point; 31 typedef Clock::duration duration; 32 typedef std::chrono::milliseconds ms; 33 typedef std::chrono::nanoseconds ns; 34 f()35void f() 36 { 37 time_point t0 = Clock::now(); 38 assert(!m.try_lock()); 39 assert(!m.try_lock()); 40 assert(!m.try_lock()); 41 while(!m.try_lock()) 42 ; 43 time_point t1 = Clock::now(); 44 m.unlock(); 45 ns d = t1 - t0 - ms(250); 46 assert(d < ms(200)); // within 200ms 47 } 48 main(int,char **)49int main(int, char**) 50 { 51 m.lock(); 52 std::thread t = support::make_test_thread(f); 53 std::this_thread::sleep_for(ms(250)); 54 m.unlock(); 55 t.join(); 56 57 return 0; 58 } 59