User Data Messages

You can associate data with a capture window by using the WM_CAP_GET_USER_DATA and WM_CAP_SET_USER_DATA messages (or the capGetUserData and capSetUserData macros). You can retrieve a LONG data value by using the WM_CAP_GET_USER_DATA message and set a LONG data value by using the WM_CAP_SET_USER_DATA message.