IDeviceTopology::GetSubunit
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IDeviceTopology::GetSubunit
The GetSubunit method gets the subunit that is specified by a subunit number.
HRESULT GetSubunit( UINT nIndex, ISubunit **ppSubunit );
Parameters
nIndex
[in] The subunit number. If a device topology contains n subunits, the subunits are numbered from 0 to n – 1. To get the number of subunits in the device topology, call the IDeviceTopology::GetSubunitCount method.
ppSubunit
[out] Pointer to a pointer variable into which the method writes the address of the ISubunit interface of the subunit object. 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 GetSubunit call fails, *ppSubunit 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_INVALIDARG | Parameter nIndex is out of range. |
E_POINTER | Pointer ppSubunit is NULL. |
Requirements
Client: Windows Vista
Header: Include Devicetopology.h.
See Also
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