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waveInUnprepareHeader (Compact 2013)

3/26/2014

This function cleans up the preparation performed by waveInPrepareHeader. The function must be called after the device driver fills a data buffer and returns it to the application. You must call this function before freeing the data buffer.

Syntax

MMRESULT waveInUnprepareHeader(
  HWAVEIN hwi, 
  LPWAVEHDR pwh, 
  UINT cbwh 
); 

Parameters

  • hwi
    Handle to the waveform-audio input device.
  • pwh
    Pointer to a WAVEHDR structure identifying the buffer to be cleaned up.
  • cbwh
    Size, in bytes, of the WAVEHDR structure.

Return Value

One of the values described in the following table is returned.

Value

Description

MMSYSERR_NOERROR

Success.

MMSYSERR_INVALHANDLE

Specified device handle is invalid.

MMSYSERR_NODRIVER

No device driver is present.

MMSYSERR_NOMEM

Unable to allocate or lock memory.

WAVERR_STILLPLAYING

Buffer pointed to by the pwh parameter is still in the queue.

Remarks

This function complements the waveInPrepareHeader function.

You must call this function before freeing the buffer. After passing a buffer to the device driver with the waveInAddBuffer function, you must wait until the driver is finished with the buffer before calling waveInUnprepareHeader. Unpreparing a buffer that has not been prepared has no effect, and the function returns zero.

Requirements

Header

mmsystem.h

Library

coredll.lib

See Also

Reference

Waveform Audio Functions