std::stop_token(3)

NAME
std::stop_token - std::stop_token

Synopsis
   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
   constructor constructs new stop_token object
                  (public member function)
   destructor destructs the stop_token object
                  (public member function)
   operator= assigns the stop_token object
                  (public member function)

Modifiers
   swap swaps two stop_token objects
                  (public member function)

Observers
   stop_requested checks whether the associated stop-state has been requested to stop
                  (public member function)
   stop_possible checks whether associated stop-state can be requested to stop
                  (public member function)

Non-member functions
   operator== compares two std::stop_token objects
                        (function)
   swap(std::stop_token) specializes the std::swap algorithm
   (C++20) (function)

Notes
   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 Feature
   __cpp_lib_jthread 201911L (C++20) Stop token and joining thread

Example
// Run this code
 #include <iostream>
 #include <thread>
 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::this_thread::sleep_for(200ms);
     }
     std::cout << std::endl;
 }
 int main()
 {
     std::jthread thread(f, 5); // prints 5 6 7 8... for approximately 3 seconds
     std::this_thread::sleep_for(3s);
     // 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