dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

ok, *now* I know what the problem is.

You will get the same error if you replace LSM_grad.h with the
following code:

  #ifndef __FOO_H
  #define __FOO_H

  class Foo
  {
  public:

    int foo();

  };

  int Foo::foo() { return 0; }

  #endif

If, on the other hand, you define foo() directly in the class
definition:

  #ifndef __FOO_H
  #define __FOO_H

  class Foo
  {
  public:

    int foo() { return 0; }

  };

  #endif

then everything will compile. (You also need to change Class1 -->
Class2 in Class2.cpp).

I few fixes were made to FFC to get around some problems with SWIG not
being able to handle nested classes. Some function definitions were
then moved outside the classes and as a result we get this problem.

We are working on a new specification for the code that is being
generated by FFC (UFC - Unified Form-assembly Code). The plan is to
support this in the next version of FFC. Then this won't be a problem.

In the meantime, just include the form-file in one place, declare the
form object and send it around to each class that needs it (if
possible).

/Anders



On Mon, Oct 30, 2006 at 10:57:53AM +0100, Garth N. Wells wrote:
> 
> 
> Anders Logg wrote:
> > I think I found the problem. Look in your file Class2.cpp:
> > 
> >   #include "Class1.hpp"
> > 
> >   using namespace dolfin;
> > 
> >   Class1::Class1()
> >   {}
> > 
> > Notice something wrong? :-)
> >
> 
> I saw this too, but is doesn't help. You can get rid of Class2
> completely and the problem remains. The code in LSM_grad.h still gets
> compiled into Class1.o and main.o.
> 
> Garth
> 
> > /Anders
> > 
> > 
> > On Mon, Oct 30, 2006 at 10:44:09AM +0100, Garth N. Wells wrote:
> >>
> >> Dag Lindbo wrote:
> >> ...
> >>
> >>>>> I'm no C++ boffin, but it seems to me the the linker (g++) is getting
> >>>>> confused over the fact there is code in the form headers that has been
> >>>>> compiled multiple times (once for each class that uses the particular
> >>>>> form)  . Did libtool do a better job at figuring this out? How do I use
> >>>>> libtool?
> >>>>>
> >>>> Can you give a stripped down example where it goes wrong?
> >>> The attached files are _very_ simple. Just two classes (that do nothing)
> >>> and a main (that does nothing). /Dag
> >>>
> >> The problem seems to stem from LSM_grad.h containing definitions
> >> and not just declarations. The definitions are compiled each time they
> >> appear. I'm not sure how to get around it. Note that if you put the
> >> definitions for Class1 and Class2 into the header files and remove
> >> Class1.cpp and Class2.cpp, everything works.
> >>
> >> Garth
> >>
> >>
> >>>> Garth
> >>>>
> >>>>> /Dag
> >>>>>
> >>>>>> Garth
> >>>>>>
> >>>>>>> Thanks a lot!
> >>>>>>> Dag Lindbo
> >>>>>>>
> >>>>>>> _______________________________________________
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> >>>>>>> DOLFIN-dev@xxxxxxxxxx
> >>>>>>> http://www.fenics.org/mailman/listinfo/dolfin-dev
> >>>>>>>
> >>
> >>
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> > 
> 
> 
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