reserve
The reserve
command allocates contiguous disk space for the device instance s workspace.
Digital-video devices recognize this command.
wsprintf(lpstrCommand, "reserve %s %s %s",
lpszDeviceID, lpszReserve,
lpszFlags);
Parameters
lpszDeviceID
Identifier of
an MCI device. This identifier or alias is assigned when the device is opened.
lpszReserve
One or more
of the following flags:
|
in path |
Specifies
the drive and directory path (but not the name) of a temporary file used to
hold recorded data. The name of this file is specified by the device. The
temporary file is deleted when the device is closed. If this flag is omitted,
the device specifies the location of the disk space. |
|
size duration |
Specifies
the approximate amount of disk space to reserve in the workspace. The duration
value is specified in the current time format. The device bases its estimate
of the required disk space on the following parameters: the requested time,
the file format, the video and audio compression algorithm, and the compression
quality values in effect. If setvideo record is off , then space is reserved
only for audio. If setaudio
record is off , then space is reserved only for video. If both are off ,
or if duration is zero, then no space is reserved and any existing
reserved space is deallocated. If this flag is omitted, the device will use a
device-defined default. |
lpszFlags
Can be
wait , notify , test , or a combination of these. For more information about
these flags, see The Wait, Notify, and Test Flags4FW.04J.
Return Values
Returns zero
if successful or an error otherwise.
Remarks
If needed,
subsequent record
or save commands
use the space reserved by this command. If the workspace contains unsaved data,
the data is lost. Some devices do not require reserve and ignore it. If
disk space is not reserved prior to recording, the record command
performs an implied reserve with device-specific default flags. Use an
explicit reserve command if you want better control of when the delay
for disk allocation occurs, control of how much space is allocated, and control
of where the disk space is allocated. Your application can change the amount
and location of previously reserved disk space with subsequent reserve commands.
Any allocated and still unused disk space is not deallocated until any recorded
data is saved, or until the device instance is closed.
See Also