try_lock_shared.pass.cpp (1525B)
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++98, c++03, c++11 12 13 // FLAKY_TEST. 14 15 // <shared_mutex> 16 17 // class shared_timed_mutex; 18 19 // bool try_lock_shared(); 20 21 #include <shared_mutex> 22 #include <thread> 23 #include <vector> 24 #include <cstdlib> 25 #include <cassert> 26 27 #include "test_macros.h" 28 29 std::shared_timed_mutex m; 30 31 typedef std::chrono::system_clock Clock; 32 typedef Clock::time_point time_point; 33 typedef Clock::duration duration; 34 typedef std::chrono::milliseconds ms; 35 typedef std::chrono::nanoseconds ns; 36 37 38 #if !defined(TEST_HAS_SANITIZERS) 39 ms Tolerance = ms(200); 40 #else 41 ms Tolerance = ms(200 * 5); 42 #endif 43 44 void f() 45 { 46 time_point t0 = Clock::now(); 47 assert(!m.try_lock_shared()); 48 assert(!m.try_lock_shared()); 49 assert(!m.try_lock_shared()); 50 while(!m.try_lock_shared()) 51 ; 52 time_point t1 = Clock::now(); 53 m.unlock_shared(); 54 ns d = t1 - t0 - ms(250); 55 assert(d < Tolerance); // within tolerance 56 } 57 58 int main() 59 { 60 m.lock(); 61 std::vector<std::thread> v; 62 for (int i = 0; i < 5; ++i) 63 v.push_back(std::thread(f)); 64 std::this_thread::sleep_for(ms(250)); 65 m.unlock(); 66 for (auto& t : v) 67 t.join(); 68 }