Question

I cannot get the following stringstreamm to compile

stringstream qss;

qss.operator <<  "some text " ::stringstream.operator << DDateTime::date2Oracle(dFrom) ::stringstream.operator <<  " more text " ::stringstream.operator <<  DDateTime::date2Oracle(dUntil);

If I just use the << operator without the ::stringstream.operatorit complains about the operator being ambigious, now it complains about incorrect syntax…

error C2143: syntax error : missing ';' before 'std::stringstream'

EDIT:

error C2593: ‘operator <<‘ is ambiguous
c:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\include\ostream(434): could be ‘std::basic_ostream<_Elem,_Traits>::_Myt &std::basic_ostream<_Elem,_Traits>::operator <<(std::basic_ostream<_Elem,_Traits>::_Mysb *)’
with
[
_Elem=char,
_Traits=std::char_traits
]

Answer 1

Well, it is obvious that whatever type DDateTime::date2Oracle(dFrom) returns does not implement << operator. So you will have to write one yourself.

As for the syntax, first of all you have to call it just like a function which it actually is:

stringstream qss;
operator<<(
     (operator<<(qss <<  "some text ", 
                 DDateTime::date2Oracle(dFrom)) << " more text "),
      DDateTime::date2Oracle(dUntil));

And second of all, stringstream defined in std namespace, so you have to write it like std::stringstream or ::std::stringstream. ::stringstream will look for it in global namespace and there is no such class defined there.

BTW, operator<< usually is implemented as free function, so qss.operator<< wouldn’t work.