I'm trying to expose this function to Python using SWIG:
std::vector<int> get_match_stats();
And I want SWIG to generate wrapping code for Python so I can see it as a list of integers.
Adding this to the .i file:
%include "typemaps.i"
%include "std_vector.i"
namespace std
{
%template(IntVector) vector<int>;
}
I'm running SWIG Version 1.3.36 and calling swig with -Wall and I get no warnings.
I'm able to get access to a list but I get a bunch of warnings when compiling with -Wall (with g++ (GCC) 4.2.4 ) the generated C++ code that say:
warning: dereferencing type-punned pointer will break strict-aliasing rules
Am I exposing the function correctly? If so, what does the warning mean?
These are the lines before the offending line in the same function:
SWIGINTERN PyObject *_wrap_IntVector_erase__SWIG_0(PyObject *SWIGUNUSEDPARM(self), PyObject *args) {
PyObject *resultobj = 0;
std::vector *arg1 = (std::vector *) 0 ;
std::vector::iterator arg2 ;
std::vector::iterator result;
void *argp1 = 0 ;
int res1 = 0 ;
swig::PySwigIterator *iter2 = 0 ;
int res2 ;
PyObject * obj0 = 0 ;
PyObject * obj1 = 0 ;
if (!PyArg_ParseTuple(args,(char *)"OO:IntVector_erase",&obj0,&obj1)) SWIG_fail;
res1 = SWIG_ConvertPtr(obj0, &argp1,SWIGTYPE_p_std__vectorT_int_std__allocatorT_int_t_t, 0 | 0 );
if (!SWIG_IsOK(res1)) {
SWIG_exception_fail(SWIG_ArgError(res1), "in method '" "IntVector_erase" "', argument " "1"" of type '" "std::vector *""'");
}
arg1 = reinterpret_cast * >(argp1);
And this is the offending line:
res2 = SWIG_ConvertPtr(obj1, SWIG_as_voidptrptr(&iter2), swig::PySwigIterator::descriptor(), 0);
More code follows that.
The warning generated when compiling with g++ 4.2.4 is:
swig_iss_wrap.cxx: In function ‘PyObject* _wrap_IntVector_erase__SWIG_0(PyObject*, PyObject*)’: swig_iss_wrap.cxx:5885: warning: dereferencing type-punned pointer will break strict-aliasing rules
