Microsoft Speech Platform

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ISpNotifyTranslator::InitCallback

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

HRESULT InitCallback(
   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

Value	Description
S_OK	Function completed successfully.
SPERR_ALREADY_INITIALIZED	SpTranslator object is already initialized.
E_INVALIDARG	pfnCallback is invalid or bad.
FAILED(hr)	Appropriate error message.

Remarks

The translator implementation uses a hidden window to call back the client on the same thread that was used to initialize the event source. Notify 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);