PropVariantToCLSID function (propvarutil.h)

Extracts class identifier (CLSID) property value of a PROPVARIANT structure.

Syntax

HRESULT PropVariantToCLSID(
  [in]  REFPROPVARIANT propvar,
  [out] CLSID          *pclsid
);

Parameters

[in] propvar

Type: REFPROPVARIANT

Reference to a source PROPVARIANT structure.

[out] pclsid

Type: CLSID*

When this function returns, contains the extracted property value if one exists.

Return value

Type: HRESULT

If this function succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code.

Remarks

This helper function works forPROPVARIANT structures of the following types:

• VT_CLSID
• VT_BSTR
• VT_LPWSTR
• VT_ARRAY | VT_UI1

PropVariantToCLSID is used in places where the calling application expects a PROPVARIANT to hold a single CLSID or GUID value. For instance, an application obtaining values from a property store can use this to safely extract the CLSID value for GUID properties.

Examples

The following example, to be included as part of a larger program, demonstrates how to use PropVariantToCLSID to access a CLSID value in a PROPVARIANT.

// IPropertyStore *ppropstore;
// Assume variable ppropstore is initialized and valid
PROPVARIANT propvar = {0};

HRESULT hr = ppropstore->GetValue(PKEY_Sync_HandlerCollectionID, &propvar);
if (SUCCEEDED(hr))
{
        // PKEY_Sync_HandlerCollectionID is expected to produce a VT_CLSID or VT_EMPTY value.
        // PropVariantToCLSID will convert VT_EMPTY to a failure code.
        CLSID clsidCollectionID;

        hr = PropVariantToCLSID(propvar, &clsidCollectionID);
        if (SUCCEEDED(hr))
        {
             // clsidCollectionID is now valid
        }
        else
        {
            // the extraction failed
        }
        PropVariantClear(&propvar);
}

Requirements

See also

InitPropVariantFromCLSID

PropVariantToGUID

VariantToGUID