waveInOpen
The waveInOpen
function opens the given waveform-audio input device for recording.
MMRESULT waveInOpen(
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LPHWAVEIN phwi, |
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UINT uDeviceID, |
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LPWAVEFORMATEX pwfx, |
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DWORD dwCallback, |
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DWORD dwCallbackInstance, |
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DWORD fdwOpen |
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); |
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Parameters
phwi
Address
filled with a handle identifying the open waveform-audio input device. Use this
handle to identify the device when calling other waveform-audio input
functions. This parameter can be NULL if WAVE_FORMAT_QUERY is specified for fdwOpen.
uDeviceID
Identifier of
the waveform-audio input device to open. It can be either a device identifier
or a handle of an open waveform-audio input device.You can use the following
flag instead of a device identifier:
WAVE_MAPPER
The function
selects a waveform-audio input device capable of recording in the specified
format.
pwfx
Address of a WAVEFORMATEX structure that identifies
the desired format for recording waveform-audio data. You can free this
structure immediately after waveInOpen returns.
dwCallback
Address of a
fixed callback function, an event handle, a handle to a window, or the
identifier of a thread to be called during waveform-audio recording to process
messages related to the progress of recording. If no callback function is
required, this value can be zero. For more information on the callback
function, see waveInProc.
dwCallbackInstance
User-instance
data passed to the callback mechanism. This parameter is not used with the
window callback mechanism.
fdwOpen
Flags for
opening the device. The following values are defined:
CALLBACK_EVENT
The dwCallback
parameter is an event handle.
CALLBACK_FUNCTION
The dwCallback
parameter is a callback procedure address.
CALLBACK_NULL
No callback
mechanism. This is the default setting.
CALLBACK_THREAD
The dwCallback
parameter is a thread identifier.
CALLBACK_WINDOW
The dwCallback
parameter is a window handle.
WAVE_FORMAT_DIRECT
If this flag
is specified, the ACM driver does not perform conversions on the audio data.
WAVE_FORMAT_QUERY
The function
queries the device to determine whether it supports the given format, but it
does not open the device.
WAVE_MAPPED
The uDeviceID
parameter specifies a waveform-audio device to be mapped to by the wave mapper.
Return Values
Returns
MMSYSERR_NOERROR if successful or an error otherwise. Possible error values
include the following:
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MMSYSERR_ALLOCATED |
Specified
resource is already allocated. |
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MMSYSERR_BADDEVICEID |
Specified
device identifier is out of range. |
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MMSYSERR_NODRIVER |
No device
driver is present. |
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MMSYSERR_NOMEM |
Unable to
allocate or lock memory. |
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WAVERR_BADFORMAT |
Attempted
to open with an unsupported waveform-audio format. |
Remarks
Use the waveInGetNumDevs function to determine the
number of waveform-audio input devices present on the system. The device
identifier specified by uDeviceID varies from zero to one less than the
number of devices present. The WAVE_MAPPER constant can also be used as a
device identifier.
If you choose
to have a window or thread receive callback information, the following messages
are sent to the window procedure or thread to indicate the progress of
waveform-audio input: MM_WIM_OPEN, MM_WIM_CLOSE, and MM_WIM_DATA.
If you choose
to have a function receive callback information, the following messages are sent
to the function to indicate the progress of waveform-audio input: WIM_OPEN,
WIM_CLOSE, and WIM_DATA.
See Also