RE: cgicc compile on HP-UX 11.11 using aCC

[Stephen F. Booth]

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
> 
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