PropVariantToUInt32VectorAlloc function (propvarutil.h)

Article
02/22/2024

Extracts data from a PROPVARIANT structure into a newly-allocated ULONG vector.

Syntax

PSSTDAPI PropVariantToUInt32VectorAlloc(
  [in]  REFPROPVARIANT propvar,
  [out] ULONG          **pprgn,
  [out] ULONG          *pcElem
);

Parameters

[in] propvar

Type: REFPROPVARIANT

Reference to a source PROPVARIANT structure.

[out] pprgn

Type: ULONG**

When this function returns, contains a pointer to a vector of ULONG values extracted from the source PROPVARIANT structure.

[out] pcElem

Type: ULONG*

When this function returns, contains the count of ULONG values extracted from the source PROPVARIANT structure.

Return value

Type: HRESULT

This function can return one of these values.

Return code	Description
S_OK	Returns S_OK if successful, or an error value otherwise.
E_INVALIDARG	The PROPVARIANT was not of the appropriate type.

Remarks

This helper function is used in places where the calling application expects a PROPVARIANT to hold a vector of ULONG values.

If the source PROPVARIANT has type VT_VECTOR | VT_UI4 or VT_ARRAY | VT_UI4, this function extracts a vector of ULONG values into a newly allocated vector. The calling application is responsible for using CoTaskMemFree to release the vector pointed to by pprgn when it is no longer needed.

Examples

The following example, to be included as part of a larger program, demonstrates how to use PropVariantToUInt32VectorAlloc to access a ULONG vector value in a PROPVARIANT.

// PROPVARIANT propvar;
// Assume the variable propvar is initialized and valid. The application is expecting propvar to contain a vector of ULONG values.
ULONG *prgLongs;
ULONG cElems;
HRESULT hr = PropVariantToUInt32VectorAlloc(propvar, &prgLongs, &cElems);
if (SUCCEEDED(hr))
{
     // prgLongs now points to a vector of cElems ULONG.
     CoTaskMemFree(prgLongs);
}

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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