Re: Streambuf with code conversion

I have been following Langers book for some time and am trying a simple
code conversion example without much luck. Here is the code.

    #include <iostream>
    #include <ostream>
    #include <streambuf>

    template <class charT, class traits>
    class Fcgibuf: public std::basic_streambuf<charT, traits>
    {
    public:
       Fcgibuf() { setp(buffer, buffer+buffSize); }
       virtual ~Fcgibuf() { sync(); }

    protected:
       typedef typename std::basic_streambuf<charT, traits>::int_type int_type;
       typedef typename std::basic_streambuf<charT, traits>::char_type char_type;
       typedef typename std::basic_streambuf<charT, traits>::traits_type traits_type;
       int_type overflow(int_type c = traits_type::eof())
       {
          if(emptyBuffer() < 0)
             return traits_type::eof();
          if(!traits_type::eq_int_type(c, traits_type::eof()))
             return sputc(c);
          else
             return traits_type::not_eof(c);
       }
       int sync() { return emptyBuffer(); }

       int emptyBuffer();
       static const int buffSize = 8192;
       char_type buffer[buffSize];
    };

    template <class charT, class traits>
    int Fcgibuf<charT, traits>::emptyBuffer()
    {
       char outBuffer[buffSize];

       mbstate_t conversionState;
       char_type* pStreamPos;
       char* toNext;
       std::use_facet<std::codecvt<char_type, char, mbstate_t> >(this->getloc()).out(conversionState, this->pptr(), this->pbase(), pStreamPos, (char*)outBuffer, outBuffer+buffSize, toNext);
       *toNext='\0';

       std::cerr << outBuffer;

       pbump(-(this->pptr()-this->pbase()));
       return 0;
    }

    int main()
    {
       Fcgibuf<wchar_t, std::char_traits<wchar_t> > theBuffer;
       std::basic_ostream<wchar_t> theStream(&theBuffer);

       theStream << L"This is a test";

       return 0;
    }

Upon compiling g++ gives me the following error:

    tmp.cpp: In member function ?int Fcgibuf<charT,
    traits>::emptyBuffer() [with charT = wchar_t, traits =
    std::char_traits<wchar_t>]?:
    tmp.cpp:25: instantiated from ?int Fcgibuf<charT, traits>::sync()
    [with charT = wchar_t, traits = std::char_traits<wchar_t>]?
    tmp.cpp:10: instantiated from ?Fcgibuf<charT, traits>::~Fcgibuf()
    [with charT = wchar_t, traits = std::char_traits<wchar_t>]?
    tmp.cpp:51: instantiated from here
    tmp.cpp:40: error: no matching function for call to
    ?std::codecvt<wchar_t, char, __mbstate_t>::out(mbstate_t&, wchar_t*,
    wchar_t*, wchar_t*&, char*, char*, char*&) const?
    /usr/lib/gcc/x86_64-pc-linux-gnu/4.1.2/include/g++-v4/bits/codecvt.h:121:
    note: candidates are: std::codecvt_base::result
    std::__codecvt_abstract_base<_InternT, _ExternT,
    _StateT>::out(_StateT&, const _InternT*, const _InternT*, const
    _InternT*&, _ExternT*, _ExternT*, _ExternT*&) const [with _InternT =
    wchar_t, _ExternT = char, _StateT = __mbstate_t]

This error message doesn't make very much sense to me as the candidate
seems identical to the actual function call. Can anybody shed some light
on this?