Microsoft Windows CE 3.0  

WIDM_ADDBUFFER

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This message is used in an MMDRV_MESSAGE_PARAMSstructure passed to the WAV_IOControlfunction to request a waveform input driver to add an empty input buffer to its input buffer queue.

Parameters

uDeviceId
Device identifier — 0, 1, 2, and so on — for the target device.
uMsg
Specifies this message.
dwUser
Specifies a device instance identifier.
dwParam1
Pointer to a WAVEHDRstructure identifying the buffer.
dwParam2
Size, in bytes, of WAVEHDR.

Return Values

MMSYSERR_NOERROR indicates success. Otherwise, the driver returns one of the MMSYSERR or WAVERR error values declared in the Mmsystem.h header file.

Remarks

The ACM (Waveapi.dll) sends the WIDM_ADDBUFFER message by calling the audio driver's (Wavedev.dll) WAV_IOControlentry point through the DeviceIoControlfunction.

If the WHDR_PREPARED flag is not set in the dwFlagsmember of WAVEHDR, the driver returns WAVERR_UNPREPARED. If the flag is set, the driver performs the following actions: