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WAVEHDR structure (mmeapi.h)

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The WAVEHDR structure defines the header used to identify a waveform-audio buffer.

Syntax

typedef struct wavehdr_tag {
  LPSTR              lpData;
  DWORD              dwBufferLength;
  DWORD              dwBytesRecorded;
  DWORD_PTR          dwUser;
  DWORD              dwFlags;
  DWORD              dwLoops;
  struct wavehdr_tag *lpNext;
  DWORD_PTR          reserved;
} WAVEHDR, *PWAVEHDR, *NPWAVEHDR, *LPWAVEHDR;

Members

lpData

Pointer to the waveform buffer.

dwBufferLength

Length, in bytes, of the buffer.

dwBytesRecorded

When the header is used in input, specifies how much data is in the buffer.

dwUser

User data.

dwFlags

A bitwise OR of zero or more flags. The following flags are defined:

Name Description
WHDR_BEGINLOOP
 This buffer is the first buffer in a loop. This flag is used only with output buffers.
WHDR_DONE
 Set by the device driver to indicate that it is finished with the buffer and is returning it to the application.
WHDR_ENDLOOP
 This buffer is the last buffer in a loop. This flag is used only with output buffers.
WHDR_INQUEUE
 Set by Windows to indicate that the buffer is queued for playback.
WHDR_PREPARED
 Set by Windows to indicate that the buffer has been prepared with the waveInPrepareHeader or waveOutPrepareHeader function.

dwLoops

Number of times to play the loop. This member is used only with output buffers.

lpNext

Reserved.

reserved

Reserved.

Remarks

Use the WHDR_BEGINLOOP and WHDR_ENDLOOP flags in the dwFlags member to specify the beginning and ending data blocks for looping. To loop on a single block, specify both flags for the same block. Use the dwLoops member in the WAVEHDR structure for the first block in the loop to specify the number of times to play the loop.

The lpData, dwBufferLength, and dwFlags members must be set before calling the waveInPrepareHeader or waveOutPrepareHeader function. (For either function, the dwFlags member must be set to zero.)

Requirements

Requirement Value
Minimum supported client Windows 2000 Professional [desktop apps only]
Minimum supported server Windows 2000 Server [desktop apps only]
Header mmeapi.h (include Windows.h)

See also

Waveform Audio

Waveform Structures

waveInPrepareHeader

waveOutPrepareHeader