NAME¶

std::jthread::get_stop_source - std::jthread::get_stop_source

Synopsis¶

std::stop_source get_stop_source() noexcept; (since C++20)

Returns a std::stop_source associated with the same shared stop-state as held
internally by the jthread object.

Parameters¶

(none)

Return value¶

A value of type std::stop_source associated with stop-state held internally by
jthread object.

Example¶

// Run this code

#include <chrono>
#include <condition_variable>
#include <iostream>
#include <mutex>
#include <string_view>
#include <thread>

using namespace std::chrono_literals;

int main()
{
std::cout << std::boolalpha;
auto print = [](std::string_view name, const std::stop_source& source)
{
std::cout << name << ": stop_possible = " << source.stop_possible();
std::cout << ", stop_requested = " << source.stop_requested() << '\n';
};

// A worker thread
auto worker = std::jthread([](std::stop_token stoken)
{
for (int i = 10; i; --i)
{
std::this_thread::sleep_for(300ms);
if (stoken.stop_requested())
{
std::cout << " Sleepy worker is requested to stop\n";
return;
}
std::cout << " Sleepy worker goes back to sleep\n";
}
});

std::stop_source stop_source = worker.get_stop_source();
print("stop_source", stop_source);

std::cout << "\nPass source to other thread:\n";
auto stopper = std::thread(
[](std::stop_source source)
{
std::this_thread::sleep_for(500ms);
std::cout << "Request stop for worker via source\n";
source.request_stop();
},
stop_source);
stopper.join();
std::this_thread::sleep_for(200ms);
std::cout << '\n';

print("stop_source", stop_source);
}

Possible output:¶

stop_source: stop_possible = true, stop_requested = false

Pass source to other thread:
Sleepy worker goes back to sleep
Request stop for worker via source
Sleepy worker is requested to stop

stop_source: stop_possible = true, stop_requested = true