IPart::EnumPartsIncoming
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IPart::EnumPartsIncoming
The EnumPartsIncoming method gets a list of all the incoming parts—that is, the parts that reside on data paths that are upstream from this part.
HRESULT EnumPartsIncoming( IPartsList **ppParts );
Parameters
ppParts
[out] Pointer to a pointer variable into which the method writes the address of an IPartsList interface that encapsulates the list of parts that are immediately upstream from this part. Through this method, the caller obtains a counted reference to the interface. The caller is responsible for releasing the interface, when it is no longer needed, by calling the interface's Release method. If the EnumPartsIncoming call fails, *ppParts is NULL.
Return Value
If the method succeeds, it returns S_OK. If it fails, possible return codes include, but are not limited to, the values shown in the following table.
| Return code | Description |
| E_POINTER | Pointer ppParts is NULL. |
| E_NOTFOUND | This part has no links to upstream parts. |
| E_OUTOFMEMORY | Out of memory. |
Remarks
A client application can traverse a device topology against the direction of audio data flow by iteratively calling this method at each step in the traversal to get the list of parts that lie immediately upstream from the current part.
If this part has no links to upstream parts, the method returns error code E_NOTFOUND and does not create a parts list (*ppParts is NULL). For example, the method returns this error code if the IPart interface represents a connector through which data enters a device topology.
Requirements
Client: Windows Vista
Header: Include Devicetopology.h.
See Also
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