IVdsSubSystem::QueryControllers method (vdshwprv.h)

Article
02/09/2023

[Beginning with Windows 8 and Windows Server 2012, the Virtual Disk Service COM interface is superseded by the Windows Storage Management API.]

Returns an object that enumerates the online and offline controllers managed by the subsystem.

Syntax

HRESULT QueryControllers(
  [out] IEnumVdsObject **ppEnum
);

Parameters

[out] ppEnum

The address of an IEnumVdsObject interface pointer that can be used to enumerate the controllers in the subsystem as controller objects. For more information, see Working with Enumeration Objects. Callers must release the interface and each of the controller objects when they are no longer needed by calling the IUnknown::Release method.

Return value

This method can return standard HRESULT values, such as E_INVALIDARG or E_OUTOFMEMORY, and VDS-specific return values. It can also return converted system error codes using the HRESULT_FROM_WIN32 macro. Errors can originate from VDS itself or from the underlying VDS provider that is being used. Possible return values include the following.

Return code/value	Description
S_OK	Returns the enumeration of controllers. If the subsystem has no controllers, the enumeration is empty.
VDS_E_PROVIDER_CACHE_CORRUPT 0x8004241FL	This return value signals a software or communication problem inside a provider that caches information about the array. Use the IVdsHwProvider::Reenumerate method followed by the IVdsHwProvider::Refresh method to restore the cache.
VDS_E_OBJECT_DELETED 0x8004240BL	The subsystem object is no longer present.
VDS_E_OBJECT_STATUS_FAILED 0x80042431L	The subsystem is in a failed state and is unable to perform the requested operation.
VDS_E_ANOTHER_CALL_IN_PROGRESS 0x80042404L	Another operation is in progress; this operation cannot proceed until the previous operation or operations are complete.

Remarks

Use the QueryControllers method to get the number of controllers, and then count the controllers in the returned enumeration.

If the subsystem has no controllers, this method returns an empty enumeration object.

Requirements

Requirement	Value
Minimum supported client	Windows Vista [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
Target Platform	Windows
Header	vdshwprv.h
Library	Uuid.lib