DD_DXAPI_REGISTER_CALLBACK control code
A video capture driver passes DD_DXAPI_REGISTER_CALLBACK in the dwFunctionNum parameter of the DxApi function to register a callback that is called when an event occurs.
Input Parameters
- lpvInBuffer
Pointer to a DDREGISTERCALLBACK structure that contains the information required to register a callback.
Output Parameters
- lpvOutBuffer
Pointer to a DWORD that contains the DirectDraw return value.
Remarks
This function identifier can only register a single event at a time. If the client wants to be called for multiple events, it must call DD_DXAPI_REGISTER_CALLBACK multiple times.
The IRQ events are actually called at IRQ time, so the callback function must return quickly and only perform calls that are safe.
The pContext member of DDREGISTERCALLBACK contains client data that is passed back to the client when the pfnDirectDrawClose callback is called.
This function identifier can only be called from PASSIVE_LEVEL.
Requirements
Header file: Ddkmapi.h (include Ddkmapi.h)