// Fig. 17.11: CooperativeCancelation.cpp
// Using a std::jthread's built-in stop_source 
// to request that the std::jthread stop executing.
#include <chrono>
#include <fmt/format.h>
#include <iostream>
#include <mutex>
#include <random>
#include <sstream>
#include <string>
#include <string_view>
#include <thread>

// get current thread's ID as a string
std::string id() {
    std::ostringstream out;
    out << std::this_thread::get_id();
    return out.str();
}

int main() {
   // each printTask iterates until a stop is requested by another thread
   auto printTask{
      [&](std::stop_token token, std::string name) {
         // set up random-number generation 
         std::random_device rd;
         std::default_random_engine engine{rd()};
         std::uniform_int_distribution ints{500, 1000};

         // register a function to call when a stop is requested 
         std::stop_callback callback(token, [&]() {
            std::cout << fmt::format(
               "{} told to stop by thread with id {}\n", name, id());
         });

         while (!token.stop_requested()) { // run until stop requested
            auto sleepTime{std::chrono::milliseconds{ints(engine)}};

            std::cout << fmt::format(
               "{} (id: {}) going to sleep for {} ms\n",
               name, id(), sleepTime.count());

            // put thread to sleep for sleepTime milliseconds 
            std::this_thread::sleep_for(sleepTime);

            // show that task woke up 
            std::cout << fmt::format("{} working.\n", name);
         }

         std::cout << fmt::format("{} terminating.\n", name);
      }
   };

   std::cout << fmt::format("MAIN (id: {}) STARTING TASKS\n", id());

   // create two jthreads that each call printTask with a string argument
   std::jthread task1{printTask, "Task 1"};
   std::jthread task2{printTask, "Task 2"};

   // put main thread to sleep for 2 seconds 
   std::cout << "\nMAIN GOING TO SLEEP FOR 2 SECONDS\n\n";
   std::this_thread::sleep_for(std::chrono::seconds{2});

   std::cout << fmt::format("\nMAIN (id: {}) ENDS\n\n", id()); 
}



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