PropVariantGetUInt32Elem function (propvarutil.h)

Article
02/22/2024

Extracts a single unsigned Int32 element from a PROPVARIANT structure of type VT_UI4, VT_VECTOR | VT_UI4, or VT_ARRAY | VT_UI4.

Syntax

PSSTDAPI PropVariantGetUInt32Elem(
  [in]  REFPROPVARIANT propvar,
  [in]  ULONG          iElem,
  [out] ULONG          *pnVal
);

Parameters

[in] propvar

Type: REFPROPVARIANT

The source PROPVARIANT structure.

[in] iElem

Type: ULONG

A vector or array index; otherwise, iElem must be 0.

[out] pnVal

Type: ULONG*

When this function returns, contains the extracted unsigned Int32 value.

Return value

Type: HRESULT

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

Remarks

This helper function works for PROPVARIANT structures of the following types:

VT_UI4
VT_VECTOR | VT_UI4
VT_ARRAY | VT_UI4

If the source PROPVARIANT has type VT_UI4, iElem must be 0. Otherwise, iElem must be less than the number of elements in the vector or array. You can use PropVariantGetElementCount to obtain the number of elements in the vector or array.

Examples

The following example, to be included as part of a larger program, demonstrates how to use PropVariantGetUInt32Elem with an iteration statement to access the values in a PROPVARIANT.

// PROPVARIANT propvar;
// Assume the variable propvar is initialized and valid.

if ((propvar.vt & VT_TYPEMASK) == VT_UI4)
{
    UINT cElem = PropVariantGetElementCount(propvar);
    HRESULT hr = <mark type="const">S_OK</mark>;

    for (UINT iElem = 0; SUCCEEDED(hr) && iElem < cElem; iElem ++)
    {
        ULONG nValue;
        hr = PropVariantGetUInt32Elem(propvar, iElem, &nValue);

        if (SUCCEEDED(hr))
        {
            // nValue is valid now
        }
    }
}

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
Library	Propsys.lib
DLL	Propsys.dll (version 6.0 or later)
Redistributable	Windows Desktop Search (WDS) 3.0

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