const char * to std::wstring
std::wstring s2ws(const std::string& str)
{
int size_needed = MultiByteToWideChar(CP_UTF8, 0, &str[0], (int)str.size(), NULL, 0);
std::wstring wstrTo( size_needed, 0 );
MultiByteToWideChar(CP_UTF8, 0, &str[0], (int)str.size(), &wstrTo[0], size_needed);
return wstrTo;
}