std::stop_token::stop_requested
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std::stop_token
Member functions
Modifiers
Observers
stop_token::stop_requested
Non-member functions
bool stop_requested() const noexcept;
(since C++20)
Checks if the stop_token object has associated stop-state and that state has received a stop request. A default constructed stop_token has no associated stop-state, and thus has not had stop requested.
[edit] Parameters
(none)
[edit] Return value
true if the stop_token object has associated stop-state and it received a stop request, false otherwise.
[edit] 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_token & token) { std::cout << name << ": stop_possible = " << token.stop_possible(); std::cout << ", stop_requested = " << token.stop_requested() << '\n'; }; // A worker thread that will listen to stop requests auto stop_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"; } }); // A worker thread that will only stop when completed auto inf_worker = std::jthread ([]() { for (int i = 5; i; --i) { std::this_thread::sleep_for (300ms); std::cout << " Run as long as we want\n"; } }); std::stop_token def_token; std::stop_token stop_token = stop_worker.get_stop_token(); std::stop_token inf_token = inf_worker.get_stop_token(); print("def_token ", def_token); print("stop_token", stop_token); print("inf_token ", inf_token); std::cout << "\nRequest and join stop_worker:\n"; stop_worker.request_stop(); stop_worker.join(); std::cout << "\nRequest and join inf_worker:\n"; inf_worker.request_stop(); inf_worker.join(); std::cout << '\n'; print("def_token ", def_token); print("stop_token", stop_token); print("inf_token ", inf_token); }
Possible output:
def_token : stop_possible = false, stop_requested = false stop_token: stop_possible = true, stop_requested = false inf_token : stop_possible = true, stop_requested = false Request and join stop_worker: Run as long as we want Sleepy worker is requested to stop Request and join inf_worker: Run as long as we want Run as long as we want Run as long as we want Run as long as we want def_token : stop_possible = false, stop_requested = false stop_token: stop_possible = true, stop_requested = true inf_token : stop_possible = true, stop_requested = true