std::stop_source::request_stop

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std::stop_source

Member functions
stop_source::stop_source
stop_source::~stop_source
stop_source::operator=
Modifiers
stop_source::request_stop
stop_source::swap
Observers
stop_source::get_token
stop_source::stop_requested
stop_source::stop_possible
Non-member functions
swap(std::stop_source)
operator==
Helper tags
std::nostopstatestd::nostopstate_t

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bool request_stop()noexcept;		(since C++20)

Issues a stop request to the stop-state, if thestop_source object has a stop-state and it has not yet already had stop requested.

The determination is made atomically, and if stop was requested, the stop-state is atomically updated to avoid race conditions, such that:

stop_requested() andstop_possible() can be concurrently invoked on otherstop_tokens andstop_sources of the same stop-state;
request_stop() can be concurrently invoked on otherstop_source objects, and only one will actually perform the stop request.

However, see the Notes section.

[edit]Parameters

(none)

[edit]Return value

true if thestop_source object has a stop-state and this invocation made a stop request, otherwisefalse.

[edit]Postconditions

stop_possible() isfalse orstop_requested() istrue.

[edit]Notes

If therequest_stop() does issue a stop request (i.e., returnstrue), then anystop_callbacks registered for the same associated stop-state will be invoked synchronously, on the same threadrequest_stop() is issued on. If an invocation of a callback exits via an exception,std::terminate is called.

If thestop_source object has a stop-state but a stop request has already been made, this function returnsfalse. However there is no guarantee that anotherstop_source object which has just (successfully) requested stop is not still in the middle of invoking astop_callback function.

If therequest_stop() does issue a stop request (i.e., returnstrue), then all condition variables of base typestd::condition_variable_any registered with an interruptible wait forstop_tokens associated with thestop_source's stop-state will be notified.