PropVariantToCLSID function (propvarutil.h)

Article
02/22/2024

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

This is an inline function, with its source code provided in the header. It is not included in any .dll or .lib file.

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

Requirement	Value
Minimum supported client	Windows XP with SP2, Windows Vista [desktop apps only]
Minimum supported server	Windows Server 2003 with SP1 [desktop apps only]
Target Platform	Windows
Header	propvarutil.h
Redistributable	Windows Desktop Search (WDS) 3.0

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