Re: Can i use CComPtr in CSimplemap?

From:

"Igor Tandetnik" <itandetnik@mvps.org>

Newsgroups:

microsoft.public.vc.atl

Date:

Tue, 16 Dec 2008 18:33:08 -0500

Message-ID:

<ugWGoa9XJHA.868@TK2MSFTNGP06.phx.gbl>

wtller <wtller@yahoo.com> wrote:

and here, CSimpleMap use the newer alloc'd object's address:

void SetAtIndex(int nIndex, TKey& key, TVal& val)
{
ATLASSERT(nIndex >= 0 && nIndex < m_nSize);
new(&m_aKey[nIndex]) Wrapper<TKey>(key);

but CComPtr cannot use it's address if it's member 'p' isn't null

//The assert on operator& usually indicates a bug. If this is really
//what is needed, however, take the address of the p member
explicitly. T** operator&()
{
ATLASSERT(p==NULL);
return &p;
}

Which VC version are you running? In my copy of VC7.1 and VC8,
SetAtIndex (well, actually, InternalSetAtIndex) looks differently:

void InternalSetAtIndex(int nIndex, const TKey& key, const TVal& val)
{
  new(m_aKey + nIndex) Wrapper<TKey>(key);
  new(m_aVal + nIndex) Wrapper<TVal>(val);
}

This neatly bypasses the pitfall of an overloaded operator&. With the
code you show, I'm afraid you are sadly out of luck.
--
With best wishes,
    Igor Tandetnik

With sufficient thrust, pigs fly just fine. However, this is not
necessarily a good idea. It is hard to be sure where they are going to
land, and it could be dangerous sitting under them as they fly
overhead. -- RFC 1925