[Swig-devel] [ swig-Bugs-2359417 ] Type system broken for pointers and the STL

[SourceForge.net <no...@so...>]

Bugs item #2359417, was opened at 2008-11-29 17:51
Message generated for change (Tracker Item Submitted) made by Item Submitter
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=101645&aid=2359417&group_id=1645

Please note that this message will contain a full copy of the comment thread,
including the initial issue submission, for this request,
not just the latest update.
Category: python
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: William Fulton (wsfulton)
Assigned to: Nobody/Anonymous (nobody)
Summary: Type system broken for pointers and the STL

Initial Comment:
The type system is broken when using the STL and pointers. Testcase below (li_std_vector_ptr.i - checked into svn):

%module li_std_vector_ptr

%include "std_vector.i"

%template(IntPtrVector) std::vector<int *>;

%inline %{
#include <iostream>
using namespace std;
int* makeIntPtr(int v) {
  return new int(v);
}
double* makeDoublePtr(double v) {
  return new double(v);
}

#if 1
int** makeIntPtrPtr(int* v) {
  return new int*(v);
}
#endif

void displayVector(std::vector<int *> vpi) {
  cout << "displayVector..." << endl;
  for (int i=0; i<vpi.size(); ++i)
    cout << *vpi[i] << endl;
}
%}


The following Python code fails:

from li_std_vector_ptr import *

ip1 = makeIntPtr(11)
ip2 = makeIntPtr(22)

vi = IntPtrVector((ip1, ip2))
displayVector(vi)

Traceback (most recent call last):
  File "./li_std_vector_ptr_runme.py", line 6, in <module>
    vi = IntPtrVector((ip1, ip2))
  File "/home/william/swig/trunk/Examples/test-suite/python/li_std_vector_ptr.py", line 122, in __init__
    this = _li_std_vector_ptr.new_IntPtrVector(*args)
NotImplementedError: Wrong number of arguments for overloaded function 'new_IntPtrVector'.
  Possible C/C++ prototypes are:
    std::vector< int * >()
    std::vector< int * >(std::vector< int * > const &)
    std::vector< int * >(std::vector< int * >::size_type)
    std::vector< int * >(std::vector< int * >::size_type,std::vector< int * >::value_type)

Something to do with int ** in the type system causes it to fail, because if the makeIntIntPtr() method is removed, then it works. But I think it works by chance more than anything else as in SWIG_Python_ConvertPtrAndOwn(), swig_type_info *ty is zero, when it should contain type information for "int *". 

The problem was previously masked but since fixing invalid STL conversions, the problem is more visible, see svn changeset 10958.


----------------------------------------------------------------------

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=101645&aid=2359417&group_id=1645