IDirectSound::SetCooperativeLevel

IDirectSound::SetCooperativeLevel

The IDirectSound::SetCooperativeLevel method sets the cooperative level of the application for this sound device.

HRESULT SetCooperativeLevel(

HWND hwnd,

DWORD dwLevel

);

Parameters

hwnd

Window handle to the application.

dwLevel

Requested priority level. Specify one of the following values:

DSSCL_EXCLUSIVE

Sets the application to the exclusive level. When it has the input focus, the application will be the only one audible (sounds from applications with the DSBCAPS_GLOBALFOCUS flag set will be muted). With this level, it also has all the privileges of the DSSCL_PRIORITY level. DirectSound will restore the hardware format, as specified by the most recent call to the IDirectSoundBuffer::SetFormat method, once the application gains the input focus. (Note that DirectSound will always restore the wave format no matter what priority level is set.)

DSSCL_NORMAL

Sets the application to a fully cooperative status. Most applications should use this level, because it has the smoothest multitasking and resource-sharing behavior.

DSSCL_PRIORITY

Sets the application to the priority level. Applications with this cooperative level can call the IDirectSoundBuffer::SetFormat and IDirectSound::Compact methods.

DSSCL_WRITEPRIMARY

This is the highest priority level. The application has write access to the primary sound buffers. No secondary sound buffers can be played. This level cannot be set if the DirectSound driver is being emulated for the device; that is, if the IDirectSound::GetCaps method returns the DSCAPS_EMULDRIVER flag in the DSCAPS structure.

Return Values

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_ALLOCATED
DSERR_INVALIDPARAM
DSERR_UNINITIALIZED
DSERR_UNSUPPORTED

Remarks

The application must set the cooperative level by calling this method before its buffers can be played. The recommended cooperative level is DSSCL_NORMAL; use other priority levels when necessary. For additional information, see Cooperative Levels.

QuickInfo

  Windows NT: Use version 4.0 or later.
  Windows: Use Windows 95 OSR2 or later. Available as a redistributable for Windows 95.
  Windows CE: Unsupported.
  Header: Declared in dsound.h.
  Import Library: Use dsound.lib.