SAPI (Microsoft Speech API) CoCreateInstance failed - c++

Question

I'm trying to run a SAPI sample from a Microsoft sample page.
When I run the application (with VS2010), this line fails:
hr = cpVoice.CoCreateInstance( CLSID_SpVoice );
hr return an error code and all other code is not executed.
I don't know why I'm wrong,, because I think to use correctly the sample code in that page and I've never use this API before.
This is my complete main.cpp file. What I'm missing?
#include "stdafx.h"
#include <sapi.h>
#include <sphelper.h>
#include <atlcomcli.h>
int _tmain(int argc, _TCHAR* argv[])
{
HRESULT hr = S_OK;
CComPtr <ISpVoice> cpVoice;
CComPtr <ISpStream> cpStream;
CSpStreamFormat cAudioFmt;
//Create a SAPI Voice
hr = cpVoice.CoCreateInstance( CLSID_SpVoice );
//Set the audio format
if(SUCCEEDED(hr))
{
hr = cAudioFmt.AssignFormat(SPSF_22kHz16BitMono);
}
//Call SPBindToFile, a SAPI helper method, to bind the audio stream to the file
if(SUCCEEDED(hr))
{
hr = SPBindToFile( L"c:\\ttstemp.wav", SPFM_CREATE_ALWAYS,
&cpStream, & cAudioFmt.FormatId(),cAudioFmt.WaveFormatExPtr() );
}
//set the output to cpStream so that the output audio data will be stored in cpStream
if(SUCCEEDED(hr))
{
hr = cpVoice->SetOutput( cpStream, TRUE );
}
//Speak the text "hello world" synchronously
if(SUCCEEDED(hr))
{
hr = cpVoice->Speak( L"Hello World", SPF_DEFAULT, NULL );
}
//close the stream
if(SUCCEEDED(hr))
{
hr = cpStream->Close();
}
//Release the stream and voice object
cpStream.Release ();
cpVoice.Release();
return 0;
}

Answer 1

You have to initialize the thread using CoInitialize[Ex] prior to using CoCreateInstance API. The error code you are getting should explicitly suggest that: CO_E_NOTINITIALIZED (you should have posted it on your question!).