DSDM_UNLOCK

  • Article

This message releases a block of sound data to the driver. The driver should perform whatever actions are necessary to output the audio data to the sound device.

typedef struct {
  DWORD dwMsg;
  DWORD dwInstance;
  LPVOID pBuffer1;
  DWORD dwCount1;
  LPVOID pBuffer2;
  DWORD dwCount2;
} DSDM_UNLOCK;

Members

  • dwMsg
    Equals DSDM_UNLOCK.
  • dwInstance
    DirectSoundBuffer instance data.
  • pBuffer1
    Pointer to the beginning of the first audio block.
  • dwCount1
    The number of bytes written to pvAudio1.
  • pBuffer2
    Pointer to the beginning of the second audio block.
  • dwCount2
    The number of bytes written to pvAudio2.

Return Values

Returns DS_OK if successful, or one of the following error values otherwise.

Error value Description
DSERR_INVALIDCALL This call is not valid for the current state of this object.
DSERR_INVALIDPARAM An invalid parameter was passed to the returning function.

Remarks

The data block is actually described by two pointers; both are required because sound buffers are circular. If the locked bytes do not wrap around the end of the buffer, the second pointer is NULL. However, if the bytes do wrap around, then the second pointer points to the beginning of the buffer.

Each call to DSDM_UNLOCK is preceded by a corresponding call to DSDM_LOCK. The pointer parameters are always the same pointers as those returned by DSDM_LOCK. However, the number of bytes unlocked could be less than the number of bytes locked if the application does not fill the locked region. See DSDM_LOCK for more details.

Requirements

OS Versions: Windows CE .NET 4.0 and later.
Header: Dsdriver.h.

See Also

DSDM_LOCK | DirectSound Driver Messages

 Last updated on Tuesday, May 18, 2004

© 1992-2003 Microsoft Corporation. All rights reserved.