How to implement a callback function

[luis lenders]

Hi , i would like to implement this function:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/multimed/htm/_win32_cappreview.asp
Here fpProc is a pointer to the preview callback
function
Applications use this to get access to the videodata.
Right now i already have a preview window.

If i'm correct it is similar to this
function:http://msdn.microsoft.com/library/default.asp?url=/library/en-us/multimed/htm/_win32_capvideostreamcallback.asp

Here the structure LPVIDEOHDR lpVHdr contains the
information about the videodata. My question is how
all of this could be implemented; right now i have :

case WM_CAP_SET_CALLBACK_FRAME:
LPVIDEOHDR lpVideoHdr; //defined in vfw.h
typedef LRESULT (CALLBACK * CAPVIDEOCALLBACK)(HWND
hwnd, LPVIDEOHDR lpVideoHdr);
CAPVIDEOCALLBACK *framecallback = (CAPVIDEOCALLBACK
*)lParam;

{so what goes here? }



return TRUE;
break;

So how could i pass the data in lpVideoHdr to the
application? Any help appreciated  as i'm still quite
a beginner in this :)

Regards

Send instant messages to your online friends http://uk.messenger.yahoo.com