Hi,
I used to have the following:
class CArchive
{
public:
    // create and specify the filename to use
    CArchive(CString filename, DWORD size);
    virtual ~CArchive();

    CArchive& operator<<(bool b);
    CArchive& operator<<(BYTE by);
    CArchive& operator<<(WORD w);
    CArchive& operator<<(LONG l);
    CArchive& operator<<(DWORD dw);
    CArchive& operator<<(float f);
    CArchive& operator<<(double d);
    CArchive& operator<<(int i);
    CArchive& operator<<(short w);
    CArchive& operator<<(char ch);
    CArchive& operator<<(unsigned u);
    CArchive& operator<<(const CString& s);

};

//template function to write array to the archive
template <class ARCHIVE, class ARRAY>
ARCHIVE& ArchiveAddArray(ARCHIVE& archive, const ARRAY& array)
{
  int nSize = array.GetSize();
  archive << nSize;
  for(int n=0; n< nSize; n++)
  {
       archive << array[n];
  }

  return archive;
}

struct BBLStruct
{
    CString m_str1;
    CString m_str2;
    CString m_str3;
};

class CBBLstructArray : public CArray<BBLStruct, BBLStruct&>
{
};

class CArchiveEx : public CArchive
{
public:
    CArchiveEx(CString filename, DWORD size)
        : CArchive(filename, size) {}
    virtual ~CArchiveEx() {}

    CArchiveEx& operator<<(CBBLstructArray& BBLs)
    {        return ArchiveExAddArray(*this,BBLs);    }
};

template <class ARRAY>
CArchiveEx& ArchiveExAddArray(CArchiveEx& self, const ARRAY& array)
{
    ArchiveAddArray(self, array);
    return self;
}

in VC++ 6.0 and everything worked okay.

I'm now moving to VC 7.1 and I receive the following error:
error C2678: binary '<<' : no operator found which takes a left-hand
operand of type 'CArchiveEx' (or there is no acceptable conversion)

When I delete the method:
    CArchiveEx& operator<<(CBBLstructArray& BBLs)
    {        return ArchiveExAddArray(*this,BBLs);    }

everything is okay.

What changed in templates in VC 7.1 ? and solutions ?

Thanks

-- Dani