ISpNotifySource::SetNotifyCallbackFunction

ISpNotifySource::SetNotifyCallbackFunction sets up this instance to send notifications using a standard C-style callback function.

HRESULT SetNotifyCallbackFunction(
   SPNOTIFYCALLBACK   *pfnCallback,
   WPARAM              wParam,
   LPARAM              lParam
);

Parameters

pfnCallback

[in] The notification callback function to be used.

wParam

[in] Constant WPARAM value that will be passed to the pfnCallback function when it is called.

lParam

[in] Constant LPARAM value that will be passed to the pfnCallback function when it is called.

Return values

Remarks

It is the responsibility of the client code to control the lifetime of a notification. To remove an installed notify callback, call ISpEventSource::SetNotifySink (NULL). The final release of an object that supports ISpEventSource will automatically remove an installed notify callback.

The SAPI implementation uses a hidden window to call back the client on the same thread that was used to initialize the event source. Notification callbacks are the result of processing a window message. When this notification mechanism is used:

1. The SPNOTIFYCALLBACK method will always be called on the thread that initialized the event source or notify translator object.
2. The thread must have a window message pump.

The SPNOTIFYCALLBACK function is declared as follows:

    typedef void __stdcall SPNOTIFYCALLBACK(WPARAM wParam, LPARAM lParam);