std::stop_token
| 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 alias templates
| Type | Definition |
callback_type<Callback> (since C++26)
|
std::stop_callback<Callback>
|
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) | |
Modifiers | |
swaps two stop_token objects (public member function) | |
Observers | |
| 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
(C++20) |
compares two std::stop_token objects (function) |
(C++20) |
specializes the std::swap algorithm (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
#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