| 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: no-threads |
| 10 | // UNSUPPORTED: c++03, c++11 |
| 11 | // ALLOW_RETRIES: 2 |
| 12 | |
| 13 | // <shared_mutex> |
| 14 | |
| 15 | // template <class Mutex> class shared_lock; |
| 16 | |
| 17 | // shared_lock(mutex_type& m, try_to_lock_t); |
| 18 | |
| 19 | #include <cassert> |
| 20 | #include <chrono> |
| 21 | #include <cstdlib> |
| 22 | #include <mutex> |
| 23 | #include <shared_mutex> |
| 24 | #include <thread> |
| 25 | #include <vector> |
| 26 | |
| 27 | #include "make_test_thread.h" |
| 28 | #include "test_macros.h" |
| 29 | |
| 30 | std::shared_timed_mutex m; |
| 31 | |
| 32 | typedef std::chrono::system_clock Clock; |
| 33 | typedef Clock::time_point time_point; |
| 34 | typedef Clock::duration duration; |
| 35 | typedef std::chrono::milliseconds ms; |
| 36 | typedef std::chrono::nanoseconds ns; |
| 37 | |
| 38 | |
| 39 | // Thread sanitizer causes more overhead and will sometimes cause this test |
| 40 | // to fail. To prevent this we give Thread sanitizer more time to complete the |
| 41 | // test. |
| 42 | #if !defined(TEST_IS_EXECUTED_IN_A_SLOW_ENVIRONMENT) |
| 43 | ms Tolerance = ms(200); |
| 44 | #else |
| 45 | ms Tolerance = ms(200 * 5); |
| 46 | #endif |
| 47 | |
| 48 | void f() |
| 49 | { |
| 50 | time_point t0 = Clock::now(); |
| 51 | { |
| 52 | std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock); |
| 53 | assert(lk.owns_lock() == false); |
| 54 | } |
| 55 | { |
| 56 | std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock); |
| 57 | assert(lk.owns_lock() == false); |
| 58 | } |
| 59 | { |
| 60 | std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock); |
| 61 | assert(lk.owns_lock() == false); |
| 62 | } |
| 63 | while (true) |
| 64 | { |
| 65 | std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock); |
| 66 | if (lk.owns_lock()) |
| 67 | break; |
| 68 | std::this_thread::yield(); |
| 69 | } |
| 70 | time_point t1 = Clock::now(); |
| 71 | ns d = t1 - t0 - ms(250); |
| 72 | assert(d < Tolerance); // within tolerance |
| 73 | } |
| 74 | |
| 75 | int main(int, char**) |
| 76 | { |
| 77 | m.lock(); |
| 78 | std::vector<std::thread> v; |
| 79 | for (int i = 0; i < 5; ++i) |
| 80 | v.push_back(support::make_test_thread(f)); |
| 81 | std::this_thread::sleep_for(rtime: ms(250)); |
| 82 | m.unlock(); |
| 83 | for (auto& t : v) |
| 84 | t.join(); |
| 85 | |
| 86 | return 0; |
| 87 | } |
| 88 |