RE: cgicc compile on HP-UX 11.11 using aCC

[JACQUOT,BRYAN (HP-FtCollins,ex1)]

Hello,

I can't explain these results.  I read through my Stroustrup book
but didn't find anything which explained this behavior.
I have sent a request for help to an internal HP contact who
may be able to shed some light.  I'll let you know what I hear.

Bryan

> -----Original Message-----
> From: Stephen F. Booth [mailto:address@hidden
> Sent: Wednesday, January 16, 2002 9:15 AM
> To: 'JACQUOT,BRYAN (HP-FtCollins,ex1)'; address@hidden
> Subject: RE: cgicc compile on HP-UX 11.11 using aCC
> 
> 
> I must admit I'm a little confused, because in FormEntry.cpp the
> following code works:
> 
> CGICCNS FormEntry& 
> CGICCNS FormEntry::operator= (const FormEntry& entry)
> {}
> 
> The only difference I can see is that this operator= is a member
> function of a class in the namespace, while in MStreamable.cpp
> operator<< is just a function in the namespace.  But why is the code
> above so different than
> 
> STDNS ostream&
> CGICCNS operator<<(STDNS ostream& out,
>       const MStreamable& obj)
> {}
> 
> ??
> 
> Why would one have access to all the data structures of a namespace
> inside a member function of a class in that namespace, but 
> not inside a
> function in that namespace?  It just doesn't add up.  I guess 
> I need to
> read about namespaces a little more.  Do you have any 
> academic knowledge
> of how this is supposed to work?
> 
> -Stephen
> 
> > -----Original Message-----
> > From: address@hidden [mailto:address@hidden On
> Behalf
> > Of JACQUOT,BRYAN (HP-FtCollins,ex1)
> > Sent: Monday, January 14, 2002 11:36 AM
> > To: 'Stephen F. Booth'; 'address@hidden'
> > Subject: RE: cgicc compile on HP-UX 11.11 using aCC
> > 
> > > -----Original Message-----
> > > From: Stephen F. Booth [mailto:address@hidden
> > > Sent: Sunday, January 13, 2002 12:35 PM
> > >
> > >
> > > > > > 2)  The MStreamable.cpp file is missing the
> > > CGICC_BEGIN_NAMESPACE,
> > > > > >     and CGICC_END_NAMESPACE macros at the beginning and
> > > end of the
> > > > > >     file.  I'm not sure why it compiles correctly with gcc,
> but
> > > the
> > > > > >     HP aCC compiler gave compiler errors without 
> these macros.
> > > > > >
> > > > > >     Here's the (HP) diff -e output to fix the problem:
> > > > > >
> > > > > > BEGIN--------------------------------------------
> > > > > > 36a
> > > > > >
> > > > > > CGICC_END_NAMESPACE
> > > > > > .
> > > > > > 26a
> > > > > > CGICC_BEGIN_NAMESPACE
> > > > > >
> > > > > > .
> > > > > > END----------------------------------------------
> > > > >
> > > > > I'm not sure that MStreamable.cpp needs to have those macros-
> > > > > my general
> > > > > approach is that in longer cpp files I will use those
> > > macros, but in
> > > > > shorter files like MStreamable I use the CGICCNS macro
> > > which usually
> > > > > expands to 'cgicc::', which should take care of the scoping.
> I'm
> > > not
> > > > > sure why it didn't work.  If you look at the
> > > pre-processed output is
> > > > > there actually a namespace qualifier in front of the
> > > > > streaming operator?
> > > >
> > > > Yes, here's (some of) the output from the preprocessor:
> > > >
> > > > #line 30
> > > >  std:: ostream&
> > > >  cgicc:: operator<<( std:: ostream& out,
> > > >  const MStreamable& obj)
> > > > {
> > > >  obj.render(out);
> > > >  return out;
> > > > }
> > > >
> > > > Here are the compile errors I get when I don't include those
> macros:
> > > > (The compiler can't find the def'n for the MStreamable class.)
> > > > And adding those name space macros fixes the problem.
> > > > I am not able to explain why.
> > >
> > > I think I've made a mistake in the code-- shouldn't the
> implementation
> > > for operator<< look like
> > >
> > > STDNS ostream&
> > > CGICCNS operator<<( STDNS ostream& out,
> > >   const CGICCNS MStreamable& obj)
> > > { ... }
> > >
> > > ??
> > >
> > > It looks like I left out the CGICCNS scoping for the
> > > MStreamable object
> > > that is being written to the stream, which I guess is necessary.
> Does
> > > this check with your understanding of C++ namespaces?  Even though
> > > operator<< is a member of the cgicc namespace, it doesn't
> > > have access to
> > > all the members of that namespace until inside the function
> > > definition.
> > > But I'm confused as to why it would work with gcc and others...
> > >
> > > -Stephen
> > 
> > 
> > Ah ha, that make sense.  Because the CGICCNS scoping was omitted
> > for the MSTreabable parameter, the compiler was looking in the
> > global namespace.  Since the .h file declares MStreamable as part
> > of the CGICCNS, it appropriately couldn't find the object's
> > definition.  I don't know how gcc is finding the type of
> > MStreamable.
> > 
> > Bryan
> > 
> > _______________________________________________
> > bug-cgicc mailing list
> > address@hidden
> > http://mail.gnu.org/mailman/listinfo/bug-cgicc
> 
>