Defined in header <stop_token>
class stop_token;
(since C++20)

The stop_token class provides the means to check if a stop request has been made or can be made, for its associated std::stop_source object. It is essentially a thread-safe "view" of the associated stop-state.

The stop_token can also be passed to the constructor of std::stop_callback, such that the callback will be invoked if the stop_token's associated std::stop_source is requested to stop. And stop_token can be passed to the interruptible waiting functions of std::condition_variable_any, to interrupt the condition variable's wait if stop is requested.

Member functions

constructs new stop_token object
(public member function)
destructs the stop_token object
(public member function)
assigns the stop_token object
(public member function)
swaps two stop_token objects
(public member function)
checks whether the associated stop-state has been requested to stop
(public member function)
checks whether associated stop-state can be requested to stop
(public member function)

Non-member functions

compares two std::stop_token objects
specializes the std::swap algorithm


A stop_token object is not generally constructed independently, but rather retrieved from a std::jthread or std::stop_source. This makes it share the same associated stop-state as the std::jthread or std::stop_source.

Feature-test macro Value Std Comment
__cpp_lib_jthread 201911L (C++20) Stop token and joining thread


#include <thread>
#include <iostream>
using namespace std::literals::chrono_literals;
void f(std::stop_token stop_token, int value)
    while (!stop_token.stop_requested())
        std::cout << value++ << ' ' << std::flush;
    std::cout << std::endl;
int main()
    std::jthread thread(f, 5); // prints 5 6 7 8... for approximately 3 seconds
    // The destructor of jthread calls request_stop() and join().

Possible output:

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

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