IWMHeaderInfo::GetAttributeCount method (wmsdkidl.h)

Artikel
4/26/2023

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 It has been superseded by Source Reader and Sink Writer.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

The GetAttributeCount method returns the number of attributes defined in the header section of the ASF file. This method is replaced by IWMHeaderInfo3::GetAttributeCountEx and IWMHeaderInfo3::GetAttributeIndices, and should no longer be used.

Syntax

HRESULT GetAttributeCount(
  [in]  WORD wStreamNum,
  [out] WORD *pcAttributes
);

Parameters

[in] wStreamNum

WORD containing the stream number. Pass zero for file-level attributes.

[out] pcAttributes

Pointer to a count of the attributes.

Return value

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

Return code	Description
S_OK	The method succeeded.
NS_E_INVALID_REQUEST	The object is not in a configurable state, or no profile has been set.
E_INVALIDARG	wStreamNum is not a valid stream number, or pcAttributes is NULL.
E_POINTER	pcAttributes is not a valid pointer.
E_UNEXPECTED	The method failed for an unspecified reason.

Remarks

Attributes in MP3 files cannot be specific to a particular stream. For MP3 files, always set the stream number to zero.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only],Windows Media Format 7 SDK, or later versions of the SDK
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	wmsdkidl.h (include Wmsdk.h)
Library	Wmvcore.lib; WMStubDRM.lib (if you use DRM)

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