PropVariantToUInt64Vector function (propvarutil.h)

Extracts data from a PROPVARIANT structure into a ULONGLONG vector.

Syntax

PSSTDAPI PropVariantToUInt64Vector(
  [in]  REFPROPVARIANT propvar,
  [out] ULONGLONG      *prgn,
  [in]  ULONG          crgn,
  [out] ULONG          *pcElem
);

Parameters

[in] propvar

Type: REFPROPVARIANT

Reference to a source PROPVARIANT structure.

[out] prgn

Type: ULONGLONG*

Points to a buffer containing crgn   ULONGLONG values. When this function returns, the buffer has been initialized with pcElem   ULONGLONG elements extracted from the source PROPVARIANT.

[in] crgn

Type: ULONG

Size of the buffer pointed to by prgn, in elements.

[out] pcElem

Type: ULONG*

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

Return value

Type: HRESULT

This function can return one of these values.

Remarks

This helper function is used in places where the calling application expects a PROPVARIANT to hold a vector of ULONGLONG values with a fixed number of elements.

If the source PROPVARIANT has type VT_VECTOR | VT_UI8 or VT_ARRAY | VT_UI8, this helper function extracts up to crgn   ULONGLONG values and places them into the buffer pointed to by prgn. If the PROPVARIANT contains more elements than will fit into the prgn buffer, this function returns an error and sets pcElem to 0.

Examples

The following example, to be included as part of a larger program, demonstrates how to use PropVariantToUInt64Vector to access a ULONGLONG vector value in a PROPVARIANT.

// PROPVARIANT propvar;
// Assume the variable propvar is initialized and valid
ULONGLONG rgLongs[4]; // The application is expecting propvar to hold 4 ULONGLONGs in a vector
ULONG cElems;
HRESULT hr = PropVariantToUInt64Vector(propvar, rgLongs, ARRAYSIZE(rgLongs), &cElems);
if (SUCCEEDED(hr))
{
     if (cElems == ARRAYSIZE(rgLongs))
     {
         // The application got 4 ULONGLONGs which are now stored in rgLongs
     }
     else
     {
         // The application got cElems which are stored in the first cElems elements of rgLongs
     }
}

Requirements

See also

InitPropVariantFromUInt64Vector

PropVariantGetUInt64Elem

PropVariantToUInt64

PropVariantToUInt64VectorAlloc

VariantToUInt64Array