SafeArrayGetElement function (oleauto.h)

Article
10/13/2021

Retrieves a single element of the array.

Syntax

HRESULT SafeArrayGetElement(
  [in]  SAFEARRAY *psa,
  [in]  LONG      *rgIndices,
  [out] void      *pv
);

Parameters

[in] psa

An array descriptor created by SafeArrayCreate.

[in] rgIndices

A vector of indexes for each dimension of the array. The right-most (least significant) dimension is rgIndices[0]. The left-most dimension is stored at rgIndices[psa->cDims – 1].

[out] pv

The element of the array.

Return value

This function can return one of these values.

Return code	Description
S_OK	Success.
DISP_E_BADINDEX	The specified index is not valid.
E_INVALIDARG	One of the arguments is not valid.
E_OUTOFMEMORY	Memory could not be allocated for the element.

Remarks

This function calls SafeArrayLock and SafeArrayUnlock automatically, before and after retrieving the element. The caller must provide a storage area of the correct size to receive the data. If the data element is a string, object, or variant, the function copies the element in the correct way.

Examples

The following example is taken from the COM Fundamentals SPoly sample (Cenumpt.cpp).

STDMETHODIMP CEnumPoint::Next(
   ULONG celt,
   VARIANT  rgvar[],
   ULONG * pceltFetched)
{
   unsigned int i;
   long ix;
   HRESULT hresult;

   for(i = 0; i < celt; ++i)
      VariantInit(&rgvar[i]);

   for(i = 0; i < celt; ++i){
      // Are we at the last element?
      if(m_iCurrent == m_celts){
      hresult = S_FALSE;
         goto LDone;
   }

      ix = m_iCurrent++;
      // m_psa is a global variable that holds the safe array.
      hresult = SafeArrayGetElement(m_psa, &ix, &rgvar[i]);
      if(FAILED(hresult))
         goto LError0;
   }
   hresult = NOERROR;

LDone:;
   if (pceltFetched != NULL)
      *pceltFetched = i;

   return hresult;

LError0:;
   for(i = 0; i < celt; ++i)
      VariantClear(&rgvar[i]);
   return hresult;
}

Requirements

Requirement	Value
Target Platform	Windows
Header	oleauto.h
Library	OleAut32.lib
DLL	OleAut32.dll

Share via