Mailman 3 July 2005 - Cplusplus-sig

GCC version compatibility
by David Abrahams April 15, 2006

April 15, 2006

The following message is a courtesy copy of an article that has been posted to gmane.comp.python.devel as well. Recently people testing Boost.Python with GCC on Linux have reported that the extensions being tested have to be compiled with exactly the same version of GCC as the Python they're being loaded into, or they get mysterious crashes. That doesn't correspond to my past experience; it has always been true that, as long as the compiler used to build Python and the one used to build the extension have compatible 'C' ABIs, we've been okay. Yes, if you were going to pass types like FILE* across the Python/C API, then you additionally need to be sure that the two compilers are using the same 'C' library. That said, none of the Boost.Python tests do that. I'm wondering if there has been a well-known recent change either in Python or GCC that would account for these new reports. Any relevant information would be appreciated. -- Dave Abrahams Boost Consulting www.boost-consulting.com

8 36

RE: Wrapper for exception translation
by Gottfried.Ganssauge＠HAUFE.DE April 4, 2006

April 4, 2006

> -----Original Message----- > From: David Abrahams [mailto:dave@boost-consulting.com] > Sent: Monday, December 13, 2004 1:04 PM > To: c++-sig(a)python.org; Gottfried Ganßauge > Subject: Re: Wrapper for exception translation > > > Gottfried Ganßauge wrote: > > Hi Dave, > > > > I digged through the class_<> implementation and I think I > know what I > > must do to implement it. Like you suggested I would add another > > argument to the class_base constructor which is used as > another base > > class for the newly created class. > > Hi Gottfried, Hi Dave, > > I don't know if you're still listening, but today I offered to > implement this patch on the C++-sig (see my other post). > Are you still interested? I am still listening but was buried deeply with work so I even had to abandon the work already invested into this. Nonetheless: Yes - I'm still interested. Cheers, Gottfried P.S.: What second Post? I got 2 Copies of this one. > > > > -- > Dave Abrahams > Boost Consulting > http://www.boost-consulting.com >

5 9

Re: exporting __stdcall methods
by David Abrahams Feb. 11, 2006

Feb. 11, 2006

"John Maddock" <john(a)johnmaddock.co.uk> writes: >> Files like boost/type_traits/detail/is_mem_fun_pointer_tester.hpp >> which are outside the Boost.Python library would need to be enhanced >> to deal with __stdcall, etc. > > Should now be fixed in cvs: provided the changes don't break anything else > of course! Fantastic! Thanks, John! -- Dave Abrahams Boost Consulting www.boost-consulting.com

4 8

Custom memory management
by Eric Jardim Sept. 13, 2005

Sept. 13, 2005

Hi, as you may know I am wrapping the Qt4 library. Things are going well, but sometimes when the application ends it seg_faults. The problem is that Qt has a light "garbage collection" scheme. Every "QObject" object that you create must has a "parent" object (except toplevels). When the object is deleted, it clean all the mess of its children and so on. Maybe, child objects are beeing killed too soon and the parents can't find them. I am using the with custodian and ward at the constructors, but sometimes I do not create the object. Besides, I suspect that I reference the same C++ object more than one time which might be a problem. Any ideas of what I can do to manage this memory problem? I dropped here the backtrace of one the segfaults. #0 0xb7eda0bd in mallopt () from /lib/tls/libc.so.6 #1 0xb7ed98fb in mallopt () from /lib/tls/libc.so.6 #2 0xb7eda2e6 in mallopt () from /lib/tls/libc.so.6 #3 0xb7ed8f02 in realloc () from /lib/tls/libc.so.6 #4 0xb721739d in qRealloc (ptr=0x821da28, size=512) at global/qglobal.cpp:1098 #5 0xb7232797 in QListData::realloc (this=0x821ba00, alloc=123) at tools/qlistdata.cpp:73 #6 0xb7232ad4 in QListData::prepend (this=0x821ba00) at tools/qlistdata.cpp:115 #7 0xb72c8a2b in QList<int>::prepend (this=0x821ba00, t=@0xbffff480) at qlist.h:408 #8 0xb72c3cac in QConnectionList::remove (this=0x821b9f0, object=0x8266808) at kernel/qobject.cpp:174 #9 0xb72c66b6 in ~QObject (this=0x8266808) at kernel/qobject.cpp:642 #10 0xb72a9e95 in ~QAbstractItemModel (this=0x8266808) at kernel/qabstractitemmodel.cpp:887 #11 0xb72aa4fb in ~QAbstractListModel (this=0x8266808) at kernel/qabstractitemmodel.cpp:1975 #12 0xb79e8139 in ~QListModel (this=0x8266808) at itemviews/qlistwidget.cpp:102 #13 0xb76ab867 in ~QWidget (this=0x8253518) at kernel/qwidget.cpp:898 #14 0xb78c91e7 in ~QFrame (this=0x8253518) at widgets/qframe.cpp:209 #15 0xb7948777 in ~QAbstractScrollArea (this=0x8253518) at widgets/qabstractscrollarea.cpp:209 #16 0xb79a1ed7 in ~QAbstractItemView (this=0x8253518) at itemviews/qabstractitemview.cpp:408 #17 0xb79b445b in ~QListView (this=0x8253518) at itemviews/qlistview.cpp:247 #18 0xb79e4923 in ~QListWidget (this=0x8253518) at itemviews/qlistwidget.cpp:982 #19 0xb76ab093 in ~QWidget (this=0x8240be0) at kernel/qwidget.cpp:898 #20 0xb7d85e92 in ~auto_ptr (this=0xb7de7f2c) at memory:259 #21 0xb7d8694b in ~pointer_holder (this=0xb7de7f24) at pointer_holder.hpp:55 #22 0xb7ccfb2b in boost::python::instance_holder::instance_holder () from /usr/lib/libboost_python-gcc-mt-1_33.so.1.33.0 ... there are more backtraces but are just like "0x000000 in ?? ()" Thanks, [Eric Jardim]

3 3

[Announce] py++ first public release
by Roman Yakovenko Aug. 14, 2005

Aug. 14, 2005

Hi, I would like to introduce a new code generator for the boost.python library, called py++ . py++ is a framework of components for creating a C++ code generator for boost.python . Code generation with the py++ framework is a very flexible and highly configurable process. You can find an introduction to py++ at: 1. http://tinyurl.com/bpe2o 2. http://cvs.sourceforge.net/viewcvs.py/*checkout*/pygccxml/source/pyplusplus… Status: First of all, this project is under active development. py++ can export the following declarations: enums ( named and unnamed ) global variables operators ( partially ) free functions member functions classes py++ does not allow the user to override virtual functions from Python for exported classes, i.e. py++ does not create a wrapper class for exported classes. Currently, py++ does not have its own homepage. You can download py++ from http://sourceforge.net/projects/pygccxml. Please note that pyplusplus-0.0.1 requires pygccxml-0.6.4 . Installation instructions: for pygccxml there is a setup.py file, so installation should be a simple task. for py++ there is no setup yet. py++ is a regular python package, so place it somewhere and add its location to sys.path . Ideas, comments, suggestions or help are welcomed. Roman Yakovenko

1 2

pyste, gccxml and boost ublas, random number generator etc
by Alexis H. Rivera-Rios Aug. 8, 2005

Aug. 8, 2005

Hi, Has anybody used pyste to expose C++ code that contained boost code from the random number generator libraries, ublas, shared_ptr? It seems when pyste compiles my code the gccxml cannot compile the libraries. I think this happens because the boost libraries that I have in windows are setup to compile with VC 7.1 and gccxml is based on another compiler so compiling the templates gets messed up. Example of compiler errors are: C:\Development\PyStatATA>pyste.py --module=PyStatATA -I c:\opt\Bayes++ -I ..\Sta tATA -I c:\usr\local\include -I C:\Boost\include\boost-1_32 -I C:\opt\newmat ..\ StatATA\pystatata.pyste In file included from C:/Boost/include/boost-1_32/boost/numeric/ublas/config.hpp :29, from C:/Boost/include/boost-1_32/boost/numeric/ublas/vector.hpp :22, from c:/opt/Bayes++/BayesFilter/matSupSub.hpp:41, from c:/opt/Bayes++/BayesFilter/bayesFlt.hpp:21, from c:/opt/Bayes++/BayesFilter/UDFlt.hpp:28, from c:/opt/Bayes++/BayesFilter/allFilters.hpp:19: C:/Boost/include/boost-1_32/boost/mpl/and.hpp:32:13: operator "defined" requires an identifier C:/Boost/include/boost-1_32/boost/mpl/and.hpp:32:13: ("and" is an alternative to ken for "&&" in C++) C:/Boost/include/boost-1_32/boost/mpl/and.hpp:32:16: missing '(' in expression C:/Boost/include/boost-1_32/boost/mpl/and.hpp:43:13: operator "defined" requires an identifier C:/Boost/include/boost-1_32/boost/mpl/and.hpp:43:13: ("and" is an alternative to ken for "&&" in C++) C:/Boost/include/boost-1_32/boost/mpl/and.hpp:43:16: missing '(' in expression In file included from C:/Boost/include/boost-1_32/boost/numeric/ublas/returntype _deduction.hpp:15, from C:/Boost/include/boost-1_32/boost/numeric/ublas/traits.hpp :27, from C:/Boost/include/boost-1_32/boost/numeric/ublas/storage.hp p:29, from C:/Boost/include/boost-1_32/boost/numeric/ublas/vector.hpp :23, from c:/opt/Bayes++/BayesFilter/matSupSub.hpp:41, from c:/opt/Bayes++/BayesFilter/bayesFlt.hpp:21, from c:/opt/Bayes++/BayesFilter/UDFlt.hpp:28, from c:/opt/Bayes++/BayesFilter/allFilters.hpp:19: C:/Boost/include/boost-1_32/boost/mpl/or.hpp:33:13: operator "defined" requires ... In file included from C:/Boost/include/boost-1_32/boost/random/linear_congruential.hpp:25, from C:/Boost/include/boost-1_32/boost/random.hpp:36, from ../StatATA/random_number_generator.h:6: C:/Boost/include/boost-1_32/boost/random/detail/const_mod.hpp: In static member function `static IntType boost::random::const_mod<IntType, m>::invert_euclidian(IntType)': C:/Boost/include/boost-1_32/boost/random/detail/const_mod.hpp:152: error: conflicting types for `typedef struct boost::static_assert_test<sizeof (boost::STATIC_ASSERTION_FAILURE<(bool)(boost::integer_traits<T>::is_signed)>)> boost_static_assert_typedef___COUNTER__' C:/Boost/include/boost-1_32/boost/random/detail/const_mod.hpp:148: error: previous declaration as `typedef struct boost::static_assert_test<sizeof (boost::STATIC_ASSERTION_FAILURE<(bool)((m > 0))>)> ... C:/Boost/include/boost-1_32/boost/shared_ptr.hpp:247: error: invalid conversion from `void*' to `const char*' ... The guys from gccxml think it's because they define their compiler as __GCCXML__ and boost doesn't recognize this. Has anybody run into this? Thanks, Alexis Programming Tutorial: In Python: To do this, do this In Perl: To do this, do this or this or this or this... In C: To do this, do this, but be careful In C++: To do this, do this, but don't do this, be careful of this, watch out for this, and whatever you do, don't do this __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

6 16

Problems with Implementing Callback Python/C++-DLL
by Oleg Novychny July 30, 2005

July 30, 2005

Dear friends, Im hoping to receive some tips to my problem. At the moment Im trying to implement a callback between Python and my C++-DLL. My DLL calculates permanently some values and stores them in member-variables in one of the DLL-classes. There are some exported functions in my DLL for starting and ending the evaluating and for reading out of values from the member-variables of my DLL. My wish is to implement my DLL in such a way that my Python-script witch I use for starting my DLL will receive a notice from my DLL to that time when the new values were calculated. I can call then my Python-Function for reading out the values from the DLL synchronized. This is my DLL-header: SOUNDPROCLIB_API int StartProcessing(int fSourceRec, int fNoiseRec, int fCrackRec, int fAudioOnRec, int fBeepRec, unsigned long ulTimeMS ); SOUNDPROCLIB_API int GetResults(unsigned long* ulHz, double* dNoise, int* bAudio, int* bCrackFlag, double* dSNR, int* bBeep); SOUNDPROCLIB_API int EndProcessing(void); So I want to call my GetResults function from Python only if my DLL tells to my Python-Script do it. Here is my Python-DLL-wrapper: from ctypes import* import sys class SoundProcLib(object): def __init__(self, library): self.library = library @cdecl(c_int, library, [c_int, c_int, c_int, c_int, c_int, c_ulong]) def StartProcessing(f1, f2, f3, f4, f5, ul1): if 0 == StartProcessing._api_(f1, f2, f3, f4, f5, ul1): raise WinError() return None self.StartProcessing = StartProcessing @cdecl(c_int, library, [POINTER(c_ulong), POINTER(c_double), POINTER(c_int), POINTER(c_int), POINTER(c_double), POINTER(c_int)]) def GetResults(): ulHz,dNoise,bAudio,bCrackFlag,dSNR,bBeep = c_ulong(), c_double(), c_int(), c_int(), c_double(), c_int() if 0 == GetResults._api_(byref(ulHz),byref(dNoise),byref(bAudio),byref(bCrackFlag),byref(dSNR),byref(bBeep)): raise WinError() return ulHz.value,dNoise.value,bAudio.value,bCrackFlag.value,dSNR.value,bBeep.value self.GetResults = GetResults @cdecl(c_int, library, [c_void_p]) def EndProcessing(): if 0 == EndProcessing._api_(None): raise WinError() return None self.EndProcessing = EndProcessing @cdecl(c_void_p, library, [c_void_p]) def inittestcallback(): if 0 == inittestcallback._api_(None): raise WinError() return None self.inittestcallback = inittestcallback At the moment I started to implement my callback in such a way (I found it in a python-tutorial): PyObject *ppyobjArgList; PyObject *ppyobjResult; static PyObject *my_callback = NULL; static PyObject *my_set_callback(PyObject *dummy, PyObject *args) { PyObject *result = NULL; PyObject *temp; if (PyArg_ParseTuple(args, "O:set_callback", &temp)) { if (!PyCallable_Check(temp)) { PyErr_SetString(PyExc_TypeError, "parameter must be callable"); return NULL; } Py_XINCREF(temp); /* Add a reference to new callback */ Py_XDECREF(my_callback); /* Dispose of previous callback */ my_callback = temp; /* Remember new callback */ /* Boilerplate to return "None" */ Py_INCREF(Py_None); result = Py_None; bPyCallBackFlag = true; } return result; }; static PyMethodDef SoundMethods[] = { {"callback", my_set_callback, METH_VARARGS, "Execute a callback."}, {NULL, NULL, 0, NULL} /* Sentinel */ }; So Im not sure how can I register my_set_callback function in the already started Python-Interpreter and to explain my DLL which Python-Function is to call when the new values in my DLL were calculated. Thank you very much for your suggestions Oleg --------------------------------- Gesendet von Yahoo! Mail - Jetzt mit 1GB kostenlosem Speicher

2 1

better way of returning python objects
by Alexis H. Rivera-Rios July 29, 2005

July 29, 2005

Hi, This is my situation. There is a C++ library called gmtl that has been ported to python using Pyste and Boost.Python. In my code, I have a C++ class that looks like this --- question #1 --- class Entity { private: gmtl::Point3d position; gmtl::Vec3d velocity; gmtl::Vec3d acceleration; public: void SetPosition(const gmtl::Point3d& pos) ... gmtl::Point3d GetPosition() const ... void SetVelocity(const gmtl::Vec3d& vel) ... gmtl::Vec3d GetVelocity() const ... void SetAcceleration(const gmtl::Vec3d& acc) ... gmtl::Vec3d GetAcceleration() const ... }; I want to be able to do this in python import gmtl; <-- this I can do already because the library has python bindings from MyModule import * t = Entity t.SetPosition(gmtl.Point3d(1,2,3)) y = t.GetPosition() The only way I've figure to do this is the following: (this is an excerpt of what pyste generated, I changed the Get/Set methods to this) scope* StatATA_Entity_scope = new scope( class_< StatATA::Entity, boost::noncopyable, StatATA_Entity_Wrapper >("Entity", init< >()) .def("SetPosition", &SetPosition) .def("GetPosition", &GetPosition) ); Where, void SetPosition( StatATA::Entity &e, const object &pos ) { gmtl::Point3d p(extract<double>(pos.attr("__getitem__")(0)), extract<double>(pos.attr("__getitem__")(1)), extract<double>(pos.attr("__getitem__")(2))); e.SetPosition(p); } object GetPosition( StatATA::Entity &e ) { object main_module(( handle<>(borrowed(PyImport_AddModule("__main__"))))); object main_namespace = main_module.attr("__dict__"); object result((handle<>( PyRun_String("gmtl.Point3d()" , Py_eval_input , main_namespace.ptr() , main_namespace.ptr())) )); gmtl::Point3d t (e.GetPosition()); result[0] = t[0]; result[1] = t[1]; result[2] = t[2]; return result; } This works. But, is there a better way? ---- question #2 --- Now, my entity has additional member variables with other gmtl types. It seems that I have to repeat the same process with each type. I want to generalize that function so I can specify the object function to call and the destination type: class_< StatATA::Entity, boost::noncopyable, StatATA_Entity_Wrapper >("Entity", init< >()) .def("SetPosition", &GenericSet<Entity::SetPosition,gmtl::Point3d>) .def("SetVelocity", &GenericSet<Entity::SetVelocity,gmtl::Vec3d>) ); The closest I've got to do that is this class: template <class Object> struct GenSet { typedef void (Object::*MemberFunc) (const gmtl::Point3d&) ; MemberFunc f; GenSet(MemberFunc x) { f = x; }; void operator()(Object &obj, const object &pos) { gmtl::Point3d p(extract<double>(pos.attr("__getitem__")(0)), extract<double>(pos.attr("__getitem__")(1)), extract<double>(pos.attr("__getitem__")(2))); (obj.*f)(p); } }; So in theory I can do the following: GenSet<Entity> xxx(&Entity::SetPosition) xxx(myobject, bla) But I run into the following problems when I try to use this in the code: 1) declaring an object without the variable name gives a syntax error: GenSet<Entity> (&Entity::SetPosition) c:\Development\PyStatATA\pystatata.cpp(119): error C2761: 'void StatATA::Entity::SetPosition(const gmtl::Point3d &)' : member function redeclaration not allowed Why does that mean? 2) Passing the class to the .def function doesn't compile either: GenSet<Entity> xxx(&Entity::SetPosition) class_< StatATA::Entity, boost::noncopyable, StatATA_Entity_Wrapper >("Entity", init< >()) .def("SetPosition", &xxx) c:\Boost\include\boost-1_32\boost\python\class.hpp(500) : error C2784: 'boost::mpl::vector17<RT,most_derived<Target,ClassT>::type&,T0,T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14> boost::python::detail::get_signature(RT (__thiscall ClassT::* )(T0,T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14) volatile const,Target *)' : could not deduce template argument for 'T2 (__thiscall T3::* )(T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14,T15,T16,T17,T18) volatile const' from '`anonymous-namespace'::GenSet<Object> with [Object=StatATA::Entity]'; c:\Boost\include\boost-1_32\boost\python\signature.hpp(164) : see declaration of 'boost::python::detail::get_signature'; c:\Boost\include\boost-1_32\boost\python\class.hpp(237) : see reference to function template instantiation 'void boost::python::class_<W,X1,X2>::def_impl<W,F,boost::python::detail::def_helper<T1>>(T *,const char *,Fn,const Helper &,...) with [W=StatATA::Entity,X1=boost::noncopyable,X2=`anonymous-namespace'::StatATA_Entity_Wrapper,F=`anonymous-namespace'::GenSet<StatATA::Entity> *__w64 ,T1=const char *,T=StatATA::Entity,Fn=`anonymous-namespace'::GenSet<StatATA::Entity> *__w64 ,Helper=boost::python::detail::def_helper<const char *>]' being compiled; c:\Development\PyStatATA\pystatata.cpp(140) : see reference to function template instantiation 'boost::python::class_<W,X1,X2>::self &boost::python::class_<W,X1,X2>::def<`anonymous-namespace'::GenSet<Object>*__w64 >(const char *,F) with [W=StatATA::Entity,X1=boost::noncopyable,X2=`anonymous-namespace'::StatATA_Entity_Wrapper,Object=StatATA::Entity,F=`anonymous-namespace'::GenSet<StatATA::Entity> *__w64 ]' being compiled c:\Boost\include\boost-1_32\boost\python\class.hpp(500) : error C2780: 'boost::mpl::vector17<RT,ClassT&,T0,T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14> boost::python::detail::get_signature(RT (__thiscall ClassT::* )(T0,T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14) volatile const)' : expects 1 arguments - 2 provided; c:\Boost\include\boost-1_32\boost\python\signature.hpp(146) : see declaration of 'boost::python::detail::get_signature' c:\Boost\include\boost-1_32\boost\python\class.hpp(500) : error C2784: 'boost::mpl::vector17<RT,most_derived<Target,ClassT>::type&,T0,T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14> boost::python::detail::get_signature(RT (__thiscall ClassT::* )(T0,T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14) volatile,Target *)' : could not deduce template argument for 'T2 (__thiscall T3::* )(T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14,T15,T16,T17,T18) volatile' from '`anonymous-namespace'::GenSet<Object> with [Object=StatATA::Entity]'; c:\Boost\include\boost-1_32\boost\python\signature.hpp(164) : see declaration of 'boost::python::detail::get_signature' c:\Boost\include\boost-1_32\boost\python\class.hpp(500) : error C2780: 'boost::mpl::vector17<RT,ClassT&,T0,T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14> boost::python::detail::get_signature(RT (__thiscall ClassT::* )(T0,T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14) volatile)' : expects 1 arguments - 2 provided; c:\Boost\include\boost-1_32\boost\python\signature.hpp(146) : see declaration of 'boost::python::detail::get_signature' ... So I guess it means we can't pass functors to the .def functions? In summary, - Is there a better way to convert a c++ object to its respective python object without me having to expose the type since that has been done for me? - Assuming that my solution for the previous question is acceptable, how can I generatize my setposition function so its parameterized on the gmtl type, and object function in a way that works with the .def function? Any comments or feedback will be greatly appreciated, Alexis Programming Tutorial: In Python: To do this, do this In Perl: To do this, do this or this or this or this... In C: To do this, do this, but be careful In C++: To do this, do this, but don't do this, be careful of this, watch out for this, and whatever you do, don't do this ____________________________________________________ Start your day with Yahoo! - make it your home page http://www.yahoo.com/r/hs

1 0

boost::optional to_and_from_python converters (help wanted)
by Ralf W. Grosse-Kunstleve July 29, 2005

July 29, 2005

I've whipped up custom Python converters for boost::optional<>, free for everyone to copy: http://cvs.sourceforge.net/viewcvs.py/cctbx/boost_adaptbx/optional_conversi… Here is the corresponding extension + minimal exercise: http://cvs.sourceforge.net/viewcvs.py/cctbx/boost_adaptbx/optional_ext.cpp?… This is known to work on a large number of platforms. It enables for example (made up): boost::optional<double> safe_acos(double arg) { if (arg < -1 || arg > 1) return boost::optional<double>(); return boost::optional<double>(std::acos(arg)); } ... def("safe_acos", save_acos); In python: >>> safe_acos(-2) None >>> safe_acos(0) 1.5707963267948966 HELP WANTED: Of course, boost::optional<> converters for the built-in types + std::complex<> and std::string really should be part of Boost.Python. Could someone out here help with this project? Cheers, Ralf __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

1 0

How to tell in member function exists in Python class
by Paul F. Kunz July 28, 2005

July 28, 2005

I have a virtual C++ base class which I"m exposing to Python so that derived classes can be written in Python. Some virtual functions may be overriden in Python and some not. So in my C++ class which makes the interface between Pyton and C++, I would like to test if the Python class has implemented a member function or not. I've done the following, following Dave Abrahams' advice on a previous topic... unsigned int FunctionWrap:: dimensions () const { unsigned int dims = 0; if ( override member = this -> get_override ( "dimensions" ) ) { dims = member(); // calls the Python function } else { // didn't override it dims = FunctionBase::dimensions (); // calls the C++ base class } return dims; } This works. But, I can't find `get_override()' in the Boost.Python documeenation. Maybe I miessed it. But if not, what should I be using to test if the Python member function has been implemented?

2 2