getlength throwing error while using with wchar_t

Question

I am working on a project that is written is VScode and is working properly. But when I am trying to execute the same on gn(generate ninja), this the error I am getting:-

error: no member named 'GetLength' in 'std::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t>>'
    int sz = string.GetLength();

I am not sure what is wrong here. Any little hint will be highly appreciated.