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IEnumVARIANT::Clone
ppenum)
IEnumVARIANT FAR* FAR* ppenum
Creates a copy of the current enumeration state.
Parameter
ppenum
On return, pointer to the location of the clone enumerator.
Return Value
The SCODE obtained from the returned HRESULT is one of the following:
SCODE
| Meaning
| S_OK
| Success.
| E_OUTOFMEMORY
| Insufficient memory to complete the operation.
|
Comments
Using this function, you can record a particular point in the enumeration
sequence, then return to it at a later time. The enumerator returned is of the same
actual interface as the one that is being cloned.
There is no guarantee that exactly the same set of variants will be enumerated
the second time as was enumerated the first. Although an exact duplicate is
desirable, the outcome depends on the collection being enumerated. Some
collections (for example, an enumeration of the files in a directory) will find it
impractical to maintain this condition.
Example
The following code implements IEnumVariant::Clone for collections in the Lines sample (ENUMVAR.CPP):
STDMETHODIMP
CEnumVariant::Clone(IEnumVARIANT FAR* FAR* ppenum)
{
CEnumVariant FAR* penum = NULL;
HRESULT hr;
hr = CEnumVariant::Create(m_psa, m_cElements, &penum);
if (FAILED(hr))
goto error;
penum->AddRef();
penum->m_lCurrent = m_lCurrent;
return NOERROR;
error:
if (penum)
penum->Release();
return hr;
}
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