MCI_SIGNAL
The MCI_SIGNAL command sets a specified position in the workspace. Digital-video devices recognize this command. MCIAVI supports only one active signal at a time.
To send this command, call the mciSendCommand function with the following parameters.
MCIERROR mciSendCommand(
MCIDEVICEID wDeviceID,
MCI_SIGNAL,
DWORD dwFlags,
(DWORD) (LPMCI_DGV_SIGNAL_PARMS) lpSignal
);
Parameters
wDeviceID
Device identifier of the MCI device that is to receive the command message.
dwFlags
MCI_NOTIFY, MCI_WAIT, or MCI_TEST. For information about these flags, see The Wait, Notify, and Test Flags.
lpSignal
Pointer to an MCI_DGV_SIGNAL_PARMS structure.
Return Values
Returns zero if successful or an error otherwise.
Remarks
The window whose handle you specify in the dwCallback member of the MCI_DGV_SIGNAL_PARMS structure receives the MM_MCISIGNAL message.
The following flags apply to digital-video devices:
MCI_DGV_SIGNAL_AT
A signal position is included in the dwPosition member of the structure identified by lpSignal.
MCI_DGV_SIGNAL_CANCEL
Removes the signal position specified by the value associated with MCI_DGV_SIGNAL_USERVAL.
MCI_DGV_SIGNAL_EVERY
A signal-period value is included in the dwPeriod member of the structure identified by lpSignal.
MCI_DGV_SIGNAL_POSITION
The device will send the position value with the Windows message instead of the user-specified value.
MCI_DGV_SIGNAL_USERVAL
A data value is included in the dwUserParm member of the structure identified by lpSignal. The data value associated with this request is reported back with the Windows message.
Requirements
** 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.
See Also