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IMDServiceProvider::GetDeviceCount

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The GetDeviceCount method returns the number of installed physical or software devices that are currently attached and are known by the service provider. This method must be implemented. It must not return WMDM_E_NOTSUPPORTED or E_NOTIMPL. For more information, see the second table under Implementing Service Providers.

Syntax

HRESULT GetDeviceCount(
  DWORD*  pdwCount
);

Parameters

pdwCount

[out]  Pointer to a DWORD containing the count of known devices.

Return Values

The method returns an HRESULT. All the interface methods in Windows Media Device Manager and service provider can return any of the following classes of error codes:

  • Standard COM error codes
  • Windows error codes converted to HRESULT values
  • Windows Media Device Manager error codes

For a complete list of possible error codes, see Error Codes.

Possible values include, but are not limited to, those in the following table.

Return code Description
S_OK The method succeeded.
E_INVALIDARG The pdwCount parameter is an invalid or NULL pointer.

Remarks

The service provider should return only the number of supported devices that are currently attached to the computer.

Requirements

Header: Defined in wmsp.idl.

Library: mssachlp.lib

See Also