微软输入法 日语汉字转假名 IFELanguage，过多的汉字（大于100）转化失败

[dexin9713]

LPCWSTR msime = L"MSIME.Japan";
CLSID clsid;
IFELanguage *pIFELanguage = NULL;
BSTR BStrOut = NULL;
BSTR BStrIn = NULL;
AnsiString ansResult = "";
AnsiString ansKJRet = "";
WCHAR *wword;


try
{
OleInitialize(NULL);

if ( CLSIDFromString(const_cast<LPWSTR>(msime),&clsid) == S_FALSE )
{
return ansResult;
}


if ( CoCreateInstance(clsid,NULL,CLSCTX_INPROC_SERVER,
IID_IFELanguage2,(LPVOID*)&pIFELanguage) != S_OK )
{
return ansResult;
}

if( !pIFELanguage )
{
return ansResult;
}

if ( pIFELanguage->Open() != S_OK )
{
pIFELanguage->Release();
return ansResult;

}


ansStr = "管理機!~@#$%^&*()_+=-099238467{}[]:;'?/>.<,|\\\||機能能,アカウント,設定で前";

setlocale(LC_ALL, "");

DWORD dwNum = MultiByteToWideChar (CP_ACP, 0, ansStr.c_str(), -1, NULL, 0);

dwNum = dwNum;

wword= (WCHAR*)calloc(dwNum,sizeof(WCHAR));
memset(wword, 0, dwNum*sizeof(WCHAR));

MultiByteToWideChar( CP_ACP, 0, ansStr.c_str(), -1, wword, dwNum ) ;

BStrIn = SysAllocString(wword);

if ( pIFELanguage->GetPhonetic(BStrIn,1,-1,&BStrOut) != S_OK )
{
pIFELanguage->Close();
pIFELanguage->Release();

return ansResult;
}

ansKJRet = BStrOut;

free(wword);
::SysFreeString(BStrIn);
::SysFreeString(BStrOut);
pIFELanguage->Close();
pIFELanguage->Release();

CoUninitialize();

return ansKJRet;
}
catch (...)
{
return ansResult;
}


请教高手，我用GetPhonetic函数，转换汉字，为什么过多的汉字（大于100）总是失败，少一些的汉字没有问题？

[dexin9713]

为什么没有人，有情高手帮忙，共同研究。

[dexin9713]

api GetPhonetic 有限制，字符串不够太长