IWMHeaderInfo3::GetAttributeCountEx method (wmsdkidl.h)
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The GetAttributeCountEx method retrieves the total number of attributes associated with a specified stream number. You can also use this method to get the number of attributes not associated with a specific stream (file-level attributes), or to get the total number of attributes in the file, regardless of stream number.
Syntax
HRESULT GetAttributeCountEx(
[in] WORD wStreamNum,
[out] WORD *pcAttributes
);
Parameters
[in] wStreamNum
WORD containing the stream number for which to retrieve the attribute count. Pass zero to retrieve the count of attributes that apply to the file rather than a specific stream. Pass 0xFFFF to retrieve the total count of all attributes in the file, both stream-specific and file-level.
[out] pcAttributes
Pointer to a WORD containing the number of attributes that exist for the specified stream.
Return value
The method returns an HRESULT. Possible values include, but are not limited to, those in the following table.
| Return code | Description |
|---|---|
|
The method succeeded. |
|
pcAttributes is not a valid pointer. |
|
wStreamNum is not a valid stream number. |
Remarks
The maximum number of attributes for a single stream is 65535, the capacity of the WORD parameter, pcAttributes. If you pass 0xFFFF as wStreamNum, this method will return the total number of attributes for the entire file. This number could potentially be greater than the capacity of pcAttributes. If the number of attributes in the file is greater than 65535, this method will produce unpredictable results. In reality, no file should ever have this many attributes. If your application makes use of an extremely large number of attributes, simply make individual calls to GetAttributeCountEx for each stream and for the file-level attributes.
Requirements
| Minimum supported client | Windows 2000 Professional [desktop apps only],Windows Media Format 9 Series 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) |