open
The open
command initializes a device. All MCI devices recognize this command.
wsprintf(lpstrCommand, "open %s %s %s",
lpszDevice, lpszOpenFlags,
lpszFlags);
Parameters
lpszDevice
Identifier of
an MCI device or device driver. This can be either a device name (as given in
the registry or the SYSTEM.INI file) or the filename of the device driver. If
you specify the filename of the device driver, you can optionally include the
.DRV extension, but you should not include the path to the file.
lpszOpenFlags
Flag that
identifies what to initialize. The following table lists device types that
recognize the open command and the flags used by each type:
|
cdaudio |
alias device_alias |
type device_type |
|
digitalvideo |
alias device_alias |
style child |
|
overlay |
alias device_alias |
style
overlapped |
|
sequencer |
alias device_alias |
type device_type |
|
vcr |
alias device_alias |
type device_type |
|
videodisc |
alias device_alias |
type device_type |
|
waveaudio |
alias device_alias |
shareable |
The following
table lists the flags that can be specified in the lpszOpenFlags
parameter and their meanings:
|
alias device_alias |
Specifies
an alternate name for the given device. If specified, it must be used as the device_id
in subsequent commands. |
|
elementname |
Specifies
the name of the device element (file) loaded when the device opens. |
|
buffer buffer_size |
Sets the
size, in seconds, of the buffer used by the waveform-audio device. The
default size of the buffer is set when the waveform-audio device is installed
or configured. Typically the buffer size is set to 4 seconds. With the
MCIWAVE device, the minimum size is 2 seconds and the maximum size is 9
seconds. |
|
parent hwnd |
Specifies
the window handle of the parent window. |
|
shareable |
Initializes
the device or file as shareable. Subsequent attempts to open the device or
file fail unless you specify shareable in both the original and subsequent open
commands. The MCISEQ
sequencer and MCIWAVE devices do not support shared files. |
|
style child |
Opens a
window with a child window style. |
|
style
overlapped |
Opens a
window with an overlapped window style. |
|
style popup |
Opens a
window with a pop-up window style. |
|
style style_type |
Indicates a
window style. |
|
type device_type |
Specifies
the device type of a file. |
lpszFlags
Can be
wait , notify , or both. For more information about these flags, see The
Wait, Notify, and Test Flags.
Return Values
Returns zero
if successful or an error otherwise.
Remarks
MCI reserves
cdaudio for the CD audio device type, videodisc for the videodisc device
type, sequencer for the MIDI sequencer device type, AVIVideo for the
digital-video device type, and waveaudio for the waveform-audio device type.
As an
alternative to the type flag, MCI can select the device based on the
extension used by the file, as recorded in the registry or the [mci extension]
section of the SYSTEM.INI file.
MCI can open
AVI files by using a file-interface pointer or a stream-interface pointer. To
open a file by using either type of interface pointer, specify an at sign (@)
followed by the interface pointer in place of the file or device name for the lpszDevice
parameter. For more information about the file and stream interfaces, see AVIFile
Functions and Macros
.
The following
command opens the mysound device:
open new type waveaudio alias mysound buffer 6
With device
name new , the waveform driver prepares a new waveform resource. The command
assigns the device alias mysound and specifies a 6-second buffer.
You can
eliminate the type flag if you combine the device name with the filename. MCI
recognizes this combination when you use the following syntax:
device_name!element_name
The
exclamation point separates the device name from the filename. The exclamation
point should not be delimited by white spaces.
The following
example opens the RIGHT.WAV file using the waveaudio device:
open waveaudio!right.wav
The MCIWAVE
driver requires an asynchronous waveform-audio device.