error C2065: 'CoUninitilize' : undeclared identifier为什么会这样?

Question

我在程序里
STDMETHODIMP CB2CClientCOM::myCom(BSTR org, BSTR *signBuf)
{
AFX_MANAGE_STATE(AfxGetStaticModuleState()) int orgLen = strlen((char *)(_bstr_t)org);
char tmp[4096];
char signtmp[4096];
memset(signtmp,0,4096); INETSIGN = NULL;
hr = CoInitialize(0);
if(SUCCEEDED(hr))
{
hr = CoCreateInstance( CLSID_NetSign_ATL, NULL, CLSCTX_INPROC_SERVER,
IID_NetSign_ATL, (void**)&INETSIGN);
}
BSTR SINGDATA = INETSIGN->mymethod(((_bstr_t)org),::SysAllocString((_bstr_t)" "));

hr = NULL;
INETSIGN->Release();
::CoUninitilize();


return S_OK;
}再最后调用::CoUninitilize();的时候会报错:
error C2039: 'CoUninitilize' : is not a member of '`global namespace''
error C2065: 'CoUninitilize' : undeclared identifier这是怎么回事啊?弄不明白