PropVariantToUInt16 function (propvarutil.h)

Article
10/13/2021

Extracts a unsigned short value from a PROPVARIANT structure. If no value can be extracted, then a default value is assigned.

Syntax

PSSTDAPI PropVariantToUInt16(
  [in]  REFPROPVARIANT propvarIn,
  [out] USHORT         *puiRet
);

Parameters

[in] propvarIn

Type: REFPROPVARIANT

Reference to a source PROPVARIANT structure.

[out] puiRet

Type: USHORT*

When this function returns, contains the extracted property value if one exists; otherwise, 0.

Return value

Type: HRESULT

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

Remarks

This helper function is used in places where the calling application expects a PROPVARIANT to hold a unsigned short value. For instance, an application obtaining values from a property store can use this to safely extract the unsigned short value for UInt16 properties.

If the source PROPVARIANT has type VT_UI2, this helper function extracts the unsigned short value. Otherwise, it attempts to convert the value in the PROPVARIANT structure into a USHORT. If a conversion is not possible, PropVariantToUInt16 will return a failure code and set puiRet to 0. See PropVariantChangeType for a list of possible conversions. Of note, VT_EMPTY is successfully converted to 0.

Examples

The following example, to be included as part of a larger program, demonstrates how to use PropVariantToUInt16 to access a unsigned short value in a PROPVARIANT.

// IPropertyStore *ppropstore;

// Assume variable ppropstore is initialized and valid

PROPVARIANT propvar = {0};

HRESULT hr = ppropstore->GetValue(PKEY_FlagColor, &propvar);

if (SUCCEEDED(hr))

{

     // PKEY_FlagColor is expected to produce a VT_UI2 or VT_EMPTY value.

     // PropVariantToUInt16 will convert VT_EMPTY to 0.

     USHORT uColor;

     hr = PropVariantToUInt16(propvar, & uColor);

     if (SUCCEEDED(hr))

     {

             // uColor is now valid

     }

     else

     {

             // uColor is always 0

     }

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