125 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8//9// UNSUPPORTED: no-threads10// UNSUPPORTED: c++03, c++11, c++14, c++1711// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-self-move12 13// jthread& operator=(jthread&&) noexcept;14 15#include <atomic>16#include <cassert>17#include <concepts>18#include <stop_token>19#include <thread>20#include <type_traits>21#include <utility>22#include <vector>23 24#include "make_test_thread.h"25#include "test_macros.h"26 27static_assert(std::is_nothrow_move_assignable_v<std::jthread>);28 29int main(int, char**) {30 // If &x == this is true, there are no effects.31 {32 std::jthread j = support::make_test_jthread([] {});33 auto id = j.get_id();34 auto ssource = j.get_stop_source();35 j = std::move(j);36 assert(j.get_id() == id);37 assert(j.get_stop_source() == ssource);38 }39 40 // if joinable() is true, calls request_stop() and then join()41 // request_stop is called42 {43 std::jthread j1 = support::make_test_jthread([] {});44 bool called = false;45 std::stop_callback cb(j1.get_stop_token(), [&called] { called = true; });46 47 std::jthread j2 = support::make_test_jthread([] {});48 j1 = std::move(j2);49 assert(called);50 }51 52 // if joinable() is true, calls request_stop() and then join()53 // join is called54 {55 std::atomic_int calledTimes = 0;56 std::vector<std::jthread> jts;57 constexpr auto numberOfThreads = 10u;58 jts.reserve(numberOfThreads);59 for (auto i = 0u; i < numberOfThreads; ++i) {60 jts.emplace_back(support::make_test_jthread([&] {61 std::this_thread::sleep_for(std::chrono::milliseconds(2));62 calledTimes.fetch_add(1, std::memory_order_relaxed);63 }));64 }65 66 for (auto i = 0u; i < numberOfThreads; ++i) {67 jts[i] = std::jthread{};68 }69 70 // If join was called as expected, calledTimes must equal to numberOfThreads71 // If join was not called, there is a chance that the check below happened72 // before test threads incrementing the counter, thus calledTimed would73 // be less than numberOfThreads.74 // This is not going to catch issues 100%. Creating more threads to increase75 // the probability of catching the issue76 assert(calledTimes.load(std::memory_order_relaxed) == numberOfThreads);77 }78 79 // then assigns the state of x to *this80 {81 std::jthread j1 = support::make_test_jthread([] {});82 std::jthread j2 = support::make_test_jthread([] {});83 auto id2 = j2.get_id();84 auto ssource2 = j2.get_stop_source();85 86 j1 = std::move(j2);87 88 assert(j1.get_id() == id2);89 assert(j1.get_stop_source() == ssource2);90 }91 92 // sets x to a default constructed state93 {94 std::jthread j1 = support::make_test_jthread([] {});95 std::jthread j2 = support::make_test_jthread([] {});96 j1 = std::move(j2);97 98 assert(j2.get_id() == std::jthread::id());99 assert(!j2.get_stop_source().stop_possible());100 }101 102 // joinable is false103 {104 std::jthread j1;105 std::jthread j2 = support::make_test_jthread([] {});106 107 auto j2Id = j2.get_id();108 109 j1 = std::move(j2);110 111 assert(j1.get_id() == j2Id);112 }113 114 // LWG3788: self-assignment115 {116 std::jthread j = support::make_test_jthread([] {});117 auto oldId = j.get_id();118 j = std::move(j);119 120 assert(j.get_id() == oldId);121 }122 123 return 0;124}125