84 lines
3.1 KiB
C++
84 lines
3.1 KiB
C++
// Fig. 17.11: CooperativeCancelation.cpp
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// Using a std::jthread's built-in stop_source
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// to request that the std::jthread stop executing.
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#include <chrono>
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#include <fmt/format.h>
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#include <iostream>
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#include <mutex>
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#include <random>
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#include <sstream>
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#include <string>
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#include <string_view>
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#include <thread>
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// get current thread's ID as a string
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std::string id() {
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std::ostringstream out;
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out << std::this_thread::get_id();
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return out.str();
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}
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int main() {
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// each printTask iterates until a stop is requested by another thread
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auto printTask{
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[&](std::stop_token token, std::string name) {
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// set up random-number generation
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std::random_device rd;
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std::default_random_engine engine{rd()};
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std::uniform_int_distribution ints{500, 1000};
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// register a function to call when a stop is requested
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std::stop_callback callback(token, [&]() {
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std::cout << fmt::format(
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"{} told to stop by thread with id {}\n", name, id());
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});
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while (!token.stop_requested()) { // run until stop requested
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auto sleepTime{std::chrono::milliseconds{ints(engine)}};
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std::cout << fmt::format(
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"{} (id: {}) going to sleep for {} ms\n",
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name, id(), sleepTime.count());
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// put thread to sleep for sleepTime milliseconds
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std::this_thread::sleep_for(sleepTime);
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// show that task woke up
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std::cout << fmt::format("{} working.\n", name);
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}
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std::cout << fmt::format("{} terminating.\n", name);
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}
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};
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std::cout << fmt::format("MAIN (id: {}) STARTING TASKS\n", id());
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// create two jthreads that each call printTask with a string argument
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std::jthread task1{printTask, "Task 1"};
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std::jthread task2{printTask, "Task 2"};
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// put main thread to sleep for 2 seconds
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std::cout << "\nMAIN GOING TO SLEEP FOR 2 SECONDS\n\n";
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std::this_thread::sleep_for(std::chrono::seconds{2});
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std::cout << fmt::format("\nMAIN (id: {}) ENDS\n\n", id());
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}
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/************************************************************************
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* (C) Copyright 1992-2022 by Deitel & Associates, Inc. and *
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* Pearson Education, Inc. All Rights Reserved. *
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* *
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* DISCLAIMER: The authors and publisher of this book have used their *
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* best efforts in preparing the book. These efforts include the *
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* development, research, and testing of the theories and programs *
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* to determine their effectiveness. The authors and publisher make *
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* no warranty of any kind, expressed or implied, with regard to these *
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* programs or to the documentation contained in these books. The *
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* authors and publisher shall not be liable in any event for *
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* incidental or consequential damages in connection with, or arising *
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* out of, the furnishing, performance, or use of these programs. *
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***********************************************************************/
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