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POHow to expose std::vector<int> as a Python list using SWIG?
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copied!<p>I'm trying to expose this function to Python using SWIG:</p> <pre><code>std::vector<int> get_match_stats(); </code></pre> <p>And I want SWIG to generate wrapping code for Python so I can see it as a list of integers.</p> <p>Adding this to the .i file:</p> <pre> %include "typemaps.i" %include "std_vector.i" namespace std { %template(IntVector) vector<int>; } </pre> <p>I'm running <code>SWIG Version 1.3.36</code> and calling swig with <code>-Wall</code> and I get no warnings.</p> <p>I'm able to get access to a list but I get a bunch of warnings when compiling with <code>-Wall</code> (with <code>g++ (GCC) 4.2.4</code> ) the generated C++ code that say:</p> <pre> warning: dereferencing type-punned pointer will break strict-aliasing rules </pre> <p>Am I exposing the function correctly? If so, what does the warning mean?</p> <hr> <p>These are the lines before the offending line in the same function:</p> <pre> 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); </pre> <p>And this is the offending line:</p> <pre> res2 = SWIG_ConvertPtr(obj1, SWIG_as_voidptrptr(&iter2), swig::PySwigIterator::descriptor(), 0); </pre> <p>More code follows that.</p> <p>The warning generated when compiling with g++ 4.2.4 is:</p> <pre> 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 </pre>

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