Re: [boost] Re: in/out parameters, codingstylesandmaintenance

From: Noel Yap (Noel.Yap_at_[hidden])
Date: 2003-05-03 23:37:22

"Justin M. Lewis" wrote:
> Again, you can do everything in C that we do in C++, there is a way to do
> it, so by your argument we shouldn't have ever moved to C++.

I believe there's no way to do templates in C.  I also see no way to
have RAII in C.  I know setjmp() and longjmp() can be used as a type of
exception handling, but can it perform stack unwinding with object
destruction?

I think there's a huge value added when C++ handled virtual functions
for me rather than doing it manually in C.  There's also value added
with the casting operators since it's easier to see what's happening.  I
see no value added with c_in, c_out, or c_in_out since the same can be
accomplished with existing tools and they are no easier or harder to
spot.

>  But, the point
> here is, we know there are some nice features in C++ that make programming
> easier and cleaner, despite the fact that we CAN accomplish the same things
> in C.  So, sometimes moving on to something new is justified.  And in the
> case of c_out and c_in_out, their interfaces aren't so complex that people
> would have trouble figuring out their use.

IMHO, these wrappers are not justified.

> > >  And as I pointed out there are very old C ways of doing everything we
> > > do in C++, but we all learned C++ anyway, because there are advantages
> to
> > > the new C++ way of doing things.
> >
> > Not everything (eg templates).
> 
> You don't need templates, you can do a lot of what is done with templates
> with either macros, or void *'s

Macros don't have scope so I believe you can't just use macros.

> Maybe they're leading sheltered lives?

Or, maybe, judging from the code you've posted, you've (or someone else
has) opted to have lots out parameters in the function calls.  Like I
said before, I'll avoid out parameters whenever possible.

>  I don't know.  But, while boost
> developers may not be buying into it, the people from the C++ IRC channelw
> here I originally discussed this idea do seem to like it.  So do the people
> I work with.

I think most on this thread, including myself, like the intent.  We're
disagreeing with the implementation of the intent.

> > > Again, how do you differentiate the use of a dumb_ptr that's just you
> using
> > > a pointer, because the function is expecting data that has been
> allocated
> > > with new, from an out, or in_out param?
> >
> > One more time:
> >
> >   void f( dumb_ptr< T const > in_ );
> >   void f( dumb_ptr< T > inOut_ );
> >   dumb_ptr< T > f(); // out
> >
> >   int i = 5;
> >   dumb_ptr< int const > in( &i );
> >   dumb_ptr< int > inOut( &i );
> >   dumb_ptr< int > out = f();
> >
> >   f( in );
> >   f( inOut );
> >
> > Exactly what's confusing you with the above?

No answer to my question?  I'm really trying to understand why you're so
adamant against using one template class in favor of two or three.  Can
you answer this question, please?

Thanks,
Noel