See also MCI_UPDATE
typedef struct { DWORD dwCallback; RECT rc; HDC hDC; } MCI_ANIM_UPDATE_PARMS;
The MCI_ANIM_UPDATE_PARMS structure contains parameters for the MCI_UPDATE message for animation devices. When assigning data to the members in this structure, set the corresponding MCI flags in the lParam1 parameter of mciSendCommand to validate the members.
dwCallback
The low-order word specifies a window handle used for the MCI_NOTIFY flag.
rc
Specifies a window rectangle.
hDC
Specifies a handle to the device context.