Re: Passing SAFEARRAY of SHORTs in event causes EEMessageException

From:

"Igor Tandetnik" <itandetnik@mvps.org>

Newsgroups:

microsoft.public.vc.atl

Date:

Fri, 14 Dec 2007 07:53:18 -0500

Message-ID:

<eFY9OBlPIHA.5400@TK2MSFTNGP04.phx.gbl>

"Egbert Nierop" <egbert_nierop@nospam.invalid> wrote in message
news:0AD04991-5C82-4BA1-8DAD-FB8F6AD18435@microsoft.com

"Bjoern" <bjoern.d.rasmussen@gmail.com> wrote in message
news:1bb33c1b-6697-41ee-96dd-86f18cb55ca6@e25g2000prg.googlegroups.com...

template<class T>
class CProxyIMyAudioEvents :
public IConnectionPointImpl<T, &__uuidof(IMyAudioEvents)>
{
HRESULT Fire_OnUserAudioData( LONG nUserID, LONG nSampleRate,
SAFEARRAY* pRawAudio, LONG nSamples)
{
HRESULT hr = S_OK;
T * pThis = static_cast<T *>(this);
int cConnections = m_vec.GetSize();
for (int iConnection = 0; iConnection < cConnections; iConnection++)
{
pThis->Lock();
CComPtr<IUnknown> punkConnection = m_vec.GetAt(iConnection);
pThis->Unlock();
IDispatch * pConnection = static_cast<IDispatch
*>(punkConnection.p);

Never cast dispatch pointers.
If you do so, the reference count might become wrong.

IDispatch * pConnection = static_cast<IDispatch
*>(punkConnection.p);

This code is wizard-generated. The code is correct: the pointer is known
to actually be IDispatch*, it was cast to IUnknown* for storage and it's
safe to cast it back here.
--
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