How to Use IMessageFilter: the complete edition

#include <atlbase.h>
#include <atlcom.h>

/****************************************************/
class CClientMessageFilter :
	public CComObjectRootEx<CComSingleThreadModel>,
	public IMessageFilter
{
	BEGIN_COM_MAP(CClientMessageFilter)
		COM_INTERFACE_ENTRY(IMessageFilter)
	END_COM_MAP()

	// Implement IMessageFilter methods here
	STDMETHODIMP_(DWORD) HandleInComingCall(
	DWORD dwCallType,
	HTASK threadIDCaller,
	DWORD dwTickCount,
	LPINTERFACEINFO lpInterfaceInfo)
	{
		return E_NOTIMPL;
	}

	STDMETHODIMP_(DWORD) RetryRejectedCall(
		HTASK threadIDCallee,
		DWORD dwTimeOut,
		DWORD dwRejectType)
	{
		AtlTrace(_T("entered CClientMessageFilter::RetryRejectedCall()\n"));
		if(dwRejectType == SERVERCALL_REJECTED)
		{ return -1; }	//indicates that the call should be canceled

		//we must've got SERVERCALL_RETRYLATER 
		return dwTimeOut;
	}

	STDMETHODIMP_(DWORD) MessagePending(
		HTASK threadIDCallee,
		DWORD dwTickCount,
		DWORD dwPendingType)
	{
		AtlTrace(_T("entered CClientMessageFilter::MessagePending().\n"));
		AtlTrace(_T("\t threadIDCallee = %d \n"), threadIDCallee);
		AtlTrace(_T("\t PendingType = %d (1 TOPLEVEL; 2 NESTED)\n"), dwPendingType);
		return PENDINGMSG_CANCELCALL;
	}
};

/****************************************************/