The following code illustrates how to set periodic position-change messages from a media device.
/* Request position advise notification every 2 seconds */
USHORT usDeviceID;
HWND hwndMyWindow;
MCI_POSITION_PARMS positionparms; /* Position advise parm structure */
/* Assign hwndCallback the handle to the PM Window - this is where
MM_MCIPOSITIONCHANGE messages will be received. */
positionparms.hwndCallback = hwndMyWindow;
positionparms.ulUnits = (ULONG) 2000; /* (Current time format = MS) */
mciSendCommand(usDeviceID, /* Device ID */
MCI_SET_POSITION_ADVISE, /* MCI set position advise
message */
MCI_SET_POSITION_ADVISE_ON | MCI_WAIT,
/* Flags for this message */
(PVOID) &positionparms, /* Data structure */
0); /* No user parm */