IMFAttributes::GetUnknown method

Retrieves an interface pointer associated with a key.

Syntax


HRESULT GetUnknown(
  [in]   REFGUID guidKey,
  [in]   REFIID riid,
  [out]  LPVOID *ppv
);

Parameters

guidKey [in]

GUID that identifies which value to retrieve. The attribute type must be MF_ATTRIBUTE_IUNKNOWN.

riid [in]

Interface identifier (IID) of the interface to retrieve.

ppv [out]

Receives a pointer to the requested interface. The caller must release the interface.

Return value

The method returns an HRESULT. Possible values include, but are not limited to, those in the following table.

Return codeDescription
S_OK

The method succeeded.

E_NOINTERFACE

The attribute value is an IUnknown pointer but does not support requested interface.

MF_E_ATTRIBUTENOTFOUND

The specified key was not found.

MF_E_INVALIDTYPE

The attribute value is not an IUnknown pointer.

 

Remarks

This interface is available on the following platforms if the Windows Media Format 11 SDK redistributable components are installed:

  • Windows XP with Service Pack 2 (SP2) and later.
  • Windows XP Media Center Edition 2005 with KB900325 (Windows XP Media Center Edition 2005) and KB925766 (October 2006 Update Rollup for Windows XP Media Center Edition) installed.

Requirements

Minimum supported client

Windows Vista [desktop apps | Windows Store apps]

Minimum supported server

Windows Server 2008 [desktop apps | Windows Store apps]

Header

Mfobjects.h (include Mfidl.h)

Library

Mfuuid.lib

See also

IMFAttributes
MF_ATTRIBUTE_TYPE
Attributes and Properties

 

 

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