[Insight-developers] Multiple defined symbols : ifstream/ofstream : Examples/OperatingRoom

[Luis Ibanez]

It seems that what is different in this program is the fact
that is has multiple .cxx files and uses std::ifstream and
std::ofstream in several of them.



The program uses the following hierarchy:




        itk::LightObject      fltk::GlDrawer
             ^                      ^
             |                      |
             |                      |
             +----------+-----------+
                        |
                        |
                   li::Shape3D
                        ^
                        |
                        |
       +----------------+----------------+-------------+....
       |                |                |                other
       |                |                |                classes(*)
 li::SpineModel    li::Tube3D     li::VectorTubes3D



(*)  li::Tube3D
     li::VertebralSegment
     li::VertebralBody
     li::VertebralPedicle
     ...
     up to 21 classes.




Among them, only the following classes use fstreams:



1)  li::Shape has the following typedefs:

    typedef   ::std::ifstream     IfstreamType;
    typedef   ::std::ofstream     OfstreamType;

    and doesn't use these types in any of its methods.


2)  li::SpineModel has read and write methods:

     void Read( Shape3D::Ifstream & is );
     void Write( Shape3D::Ofstream & os, int level );


3)  li::VectorTubes3D has only a read method:

     void Read( Shape3D::Ifstream & is );

     and has an aggregate:

     std::vector< li::Tube3D::Pointer >  m_Tubes;



4)  li::Tube3D has only a Read() method:

    void Read( Shape3D::Ifstream & is );



5)  li::VertebralSegment has Read and Write methods:

     void Read( Shape3D::Ifstream & is );
     void Write( Shape3D::Ofstream & os, int level );



6)  li::VertebralBody has Read and Write methods:

     void Read( Shape3D::Ifstream & is );
     void Write( Shape3D::Ofstream & os, int level );



7)  li::VertebralPedicle has Read and Write methods:

     void Read( Shape3D::Ifstream & is );
     void Write( Shape3D::Ofstream & os, int level );




When we remove liSpineModel, we got similar error messages but
this time complaining about duplicate symbols in liVectorTubes3D.o
and if we remove liVectorTubes3D the error message moves to another
class...


The problem seems to be related with the multiple instantiations
of std::ifstream and std::ofstream. That could be the reason why
this problem doesn't shows up in the rest of the tests.


  Any suggestions ?

  Thanks

  Luis


=======================================================================

Bill Hoffman wrote:
>
> msvcprt.lib(MSVCP60.dll) : error LNK2005: "public: void __thiscall std::basic_ofstream<char,struct std::char_traits<char> >::`vbase
> destructor'(void)" (??_D?$basic_ofstream@DU?$char_traits@D@std@@@std@@QAEXXZ) already defined in liSpineModel.obj
> msvcprt.lib(MSVCP60.dll) : error LNK2005: "public: void __thiscall std::basic_ifstream<char,struct std::char_traits<char> >::`vbase destructor'(void)"
> (??_D?$basic_ifstream@DU?$char_traits@D@std@@@std@@QAEXXZ) already defined in liSpineModel.obj


> That error is saying that the ofstream destructor is defined in msvcprt.lib and
> liSplineModel.obj.

> So it is a conflict with the standard library and liSplineModel.obj.
> However, we use ostream stuff in other places in Insight with no problem.
> What is different about liSplineModel ?
>
>