Helper function to obtain an object's associated cancellation_slot.

template<
    typename T,
    typename CancellationSlot>
associated_cancellation_slot< T, CancellationSlot >::type get_associated_cancellation_slot(
    const T & t,
    const CancellationSlot & st);

Return Value

associated_cancellation_slot<T, CancellationSlot>get(t, st)