The MM_MCISIGNAL message is sent to a window to notify an application that an MCI device has reached a position defined in a previous signal (MCI_SIGNAL) command.
MM_MCISIGNAL wParam = (WPARAM) wID lParam = (LONG) lUserParm
Identifier of the device initiating the signal message.
Value passed in the dwUserParm member of the MCI_DGV_SIGNAL_PARAMS structure when the signal command has defined this callback function. Alternatively, it might contain the position value.
** Windows NT/2000/XP:** Included in Windows NT 3.1 and later.
** Windows 95/98/Me:** Included in Windows 95 and later.
** Header:** Declared in Mmsystem.h; include Windows.h.