SAPI event SPEI_WORD_BOUNDARY notification doesn't work

I have used this function to speak sentence ascynchronously .

m_cpVoice->Speak(m_sInputText,SPF_ASYNC, NULL))

I want to get notification of SPEI_WOR开发者_Python百科D_BOUNDARY event so i did these.

m_cpVoice->SetInterest(SPFEI(SPEI_WORD_BOUNDARY),SPFEI(SPEI_WORD_BOUNDARY));
m_cpVoice->SetNotifyWindowMessage(GetSafeHwnd(),CTTSDlgDlg::MSG_SAPI_EVENT,0,0);

CTTSDlgDlg::MSG_SAPI_EVENT maps to my event handler.

Am i missing something and whats the problem that i am not getting notification?

MFC requires ON_REGISTERED_MESSAGE instead of ON_MESSAGE to get your events delivered to your object.