Re: [Swig-user] Template undefined symbol swig strangeness ?

[Marcelo M. <mm...@ac...>]

Jerome Glisse wrote:

>Hi,
>
>I am trying to use template with swig but i face a strange bug
>anytime i am trying to link with a template class with function
>compiled in a file python complain for undefined symbol at
>runtime even though that this symbol appear
>(strings test.so | grep guiltysymbol)
>  
>
You need to use

  nm test.so | grep  guiltysymbol

if you see

  U  guiltysymbol

the symbol is undefined. If you have a .cxx file with the template 
definitions, you need
to compile it with the rest of the swig interface, ie, something like:

   g++ -shared -o _module.so -c module_wrap.cxx mytemplate.cxx

or just put everything in the interface file. There are other ways too, 
and you will
need to find a way to do the compiling/linking that satisfy your own 
develepment
requirements.... so, in short, this is not a swig issue, but a 
linking/compiling issue,
that have different possible solutions, and you need to think a little 
about which one
you want to pick.

Marcelo

>If i do all template class function in h everythings work.
>I attach a simple test case. Right now i am using 1.3.27
>maybe it have been fixed since but after googling few
>hours i didn't find anythings.
>
>I attach a simple test case build using build.sh
>
>thx for your help,
>Jerome Glisse
>  
>
>------------------------------------------------------------------------
>
>#include "TVector2D.hxx"
>
>#if ALLINH
>#else
>// ============================================================================
>template<class T> TVector2D<T>::TVector2D(const T& x, const T& y)
>{
>	fX = x;
>	fY = y;
>}
>
>// ============================================================================
>template<class T> TVector2D<T>::~TVector2D()
>{
>}
>
>// ============================================================================
>template<class T> TVector2D<T>::TVector2D()
>{
>}
>
>// ============================================================================
>template<class T> TVector2D<T>::TVector2D(const TVector2D<T>& v)
>{
>	fX = v.fX;
>	fY = v.fY;
>}
>
>// ============================================================================
>template<class T> TVector2D<T>&
>TVector2D<T>::operator = (const TVector2D<T>& v)
>{
>	fX = v.fX;
>	fY = v.fY;
>	return *this;
>}
>
>// ============================================================================
>template<class T> TVector2D<T> TVector2D<T>::operator + (const TVector2D& v)
>{
>	return TVector2D<T>(fX + v.fX, fY + v.fY);
>}
>
>// ============================================================================
>template<class T> bool TVector2D<T>::operator == (const TVector2D& v) const
>{
>	if (fX == v.fX && fY == v.fY)
>		return true;
>	return false;
>}
>
>// ============================================================================
>template<class T> const T& TVector2D<T>::GetX() const
>{
>	return fX;
>}
>
>// ============================================================================
>template<class T> const T& TVector2D<T>::GetY() const
>{
>	return fY;
>}
>#endif
>
>  
>
>------------------------------------------------------------------------
>
>/*
> * TVectorUnique vector of unique member class
> *
> * Copyright (C) 2005 Jerome Glisse <j.g...@gm...>
> *
> * This program is free software; you can redistribute it and/or modify
> * it under the terms of the GNU General Public License as published by
> * the Free Software Foundation; either version 2 of the License, or
> * (at your option) any later version.
> *
> * This program is distributed in the hope that it will be useful,
> * but WITHOUT ANY WARRANTY; without even the implied warranty of
> * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> * GNU General Public License for more details.
> *
> * You should have received a copy of the GNU General Public License
> * along with this program; if not, write to the Free Software
> * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
> */
>#ifndef _VECTORUNIQUE_H
>#define _VECTORUNIQUE_H
>
>#include <vector>
>#include <string>
>
>template<class T> class TVectorUnique {
>private:
>	std::vector<T>	fVector;
>
>public:
>	TVectorUnique();
>	TVectorUnique(const TVectorUnique<T>& v);
>	~TVectorUnique();
>
>	const T& operator [] (int i) const;
>
>	void clear();
>	bool push_back(const T& e);
>	int size() const;
>};
>
>#endif
>
>  
>
>------------------------------------------------------------------------
>
>#!/usr/bin/python
>
># MODULES ---------------------------------------------------------------------
>import test
>
># MAIN ------------------------------------------------------------------------
>t = test.Vector2D(2, 5)
>print t.GetX(),t.GetY()
>  
>