IDirectSoundBuffer::Unlock

Article
06/03/2016

[The feature associated with this page, DirectSound, is a legacy feature. It has been superseded by WASAPI and Audio Graphs. Media Casting have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use Media Casting instead of DirectSound, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

This method releases a locked sound buffer.

Syntax

HRESULT Unlock( LPVOID lpvAudioPtr1, DWORD dwAudioBytes1, LPVOID lpvAudioPtr2, DWORD dwAudioBytes2 );

Parameters

lpvAudioPtr1
Address of the value retrieved in the lplpvAudioPtr1 parameter of the IDirectSoundBuffer::Lock method.
dwAudioBytes1
Number of bytes actually written to the lpvAudioPtr1 parameter. It should not exceed the number of bytes returned by the IDirectSoundBuffer::Lock method.
lpvAudioPtr2
Address of the value retrieved in the lplpvAudioPtr2 parameter of the IDirectSoundBuffer::Lock method.
dwAudioBytes2
Number of bytes actually written to the lpvAudioPtr2 parameter. It should not exceed the number of bytes returned by the IDirectSoundBuffer::Lock method.

Return Value

If the method succeeds, the return value is DS_OK.

If the method fails, the return value may be one of the following error values:

DSERR_INVALIDCALL

DSERR_INVALIDPARAM

DSERR_PRIOLEVELNEEDED

Remarks

An application must pass both pointers, lpvAudioPtr1 and lpvAudioPtr2, returned by the IDirectSoundBuffer::Lock method to ensure the correct pairing of IDirectSoundBuffer::Lock and IDirectSoundBuffer::Unlock. The second pointer is needed even if 0 bytes were written to the second pointer.

Applications must pass the number of bytes actually written to the two pointers in the parameters dwAudioBytes1 and dwAudioBytes2.

Make sure the sound buffer does not remain locked for long periods of time.

Requirements

Header: Declared in DSound.h.

Library: Use Dsound.lib.