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std::stop_callback<Callback>::stop_callback

template< class C >
explicit stop_callback( const std::stop_token& st, C&& cb ) noexcept(/*see below*/);
 (1) (since C++20) 
template< class C >
explicit stop_callback( std::stop_token&& st, C&& cb ) noexcept(/*see below*/);
 (2) (since C++20) 
stop_callback( const stop_callback& ) = delete;
 (3) (since C++20) 
stop_callback( stop_callback&& ) = delete;
 (4) (since C++20)

Constructs a new stop_callback object, saving and registering the cb callback function into the given std::stop_token's associated stop-state, for later invocation if stop is requested on the associated std::stop_source.

1) Constructs a stop_callback for the given st std::stop_token (copied), with the given invocable callback function cb.
2) Constructs a stop_callback for the given st std::stop_token (moved), with the given invocable callback function cb.
3,4) stop_callback is neither CopyConstructible nor MoveConstructible.

Both constructors participate overload resolution only if Callback and C satisfy constructible_from of std::constructible_from<Callback, C>. If Callback and C satisfy the concept but fail to satisfy its semantic requirement, the behavior is undefined.

Parameters

st - a std::stop_token object to register this stop_callback object with
cb - the type to invoke if stop is requested

Exceptions

1,2)
noexcept specification:
noexcept(std::is_nothrow_constructible_v<Callback, C>)
Any exception thrown by constructor-initializing the given callback into the stop_callback object.

Notes

If st.stop_requested() == true for the passed-in std::stop_token, then the callback function is invoked in the current thread before the constructor returns.

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