Mailman 3 September 2006 - Cplusplus-sig

Base class defined in other header file not included in bp::bases<>
by Haridev, Meghana Sept. 14, 2008

Sept. 14, 2008

Hi Folks, I'm having some trouble generating boost-python wrapper code using pyplusplus for a derived class which has one of its base classes defined in another file. Simple scenario: mydir/ other.hpp: class baseB{ }; hierarchy.hpp: #include "other.hpp" class baseA{ }; class derivedC: public baseA, public baseB{ }; generate_code.py: import os from pyplusplus import module_builder mb = module_builder.module_builder_t( files=['hierarchy.hpp'] ) mb.build_code_creator( module_name='inherit' ) mb.code_creator.user_defined_directories.append( os.path.abspath('.') ) mb.write_module('boost_hierarchy.cpp') ------------------------------------------------------------------------ ------------------------------------------------- Generated code (boost_hierarchy.cpp) looks like this: // This file has been generated by pyplusplus. #include "boost/python.hpp" #include "hierarchy.hpp" namespace bp = boost::python; BOOST_PYTHON_MODULE(inherit){ bp::class_< baseA >( "baseA" ); bp::class_< derivedC, bp::bases< baseA > >( "derivedC" ); } How can I get pyplusplus to add 'baseB' to bp::bases<> for 'derivedC' class when 'baseB' class is defined in another file (present in the same directory or different directory)? When I move the definition of 'baseB' class to hierarchy.hpp, boost wrapper for 'derivedC' is correctly generated as: bp::class_< derivedC, bp::bases< baseA, baseB > >( "derivedC" ); Thanks, -Meghana.

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C++ singleton
by Emmanuel Taurel Oct. 31, 2007

Oct. 31, 2007

Hello everybody, I am actually writing an interface to python for an existing C++ library using Boost. This library has a C++ singleton class. This class has only one constructor (with arguments) which is "protected" because it's a singleton. I am not able to build a Boost interface to this class because the compiler complains that the constructor I have given to Boost in the class_xxx constructor argument is not public (which is true) ! Therefore, my question is simple : How is it possible to interface such a class with only one constructor which is protected and a static method to create/access the object ? Thank's very much for your answer. Sincerely Emmanuel Taurel (etaurel(a)cells.es) PS : By the way, is there a searchable archive of this mailing list ?

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pointer_holder and pure virtual base classes
by Allen Bierbaum Oct. 29, 2006

Oct. 29, 2006

This is a followup to my efforts in the thread here: http://thread.gmane.org/gmane.comp.python.c++/10125/focus=10125 I seemed to have everything working but I just ran into a new problem. A simplified summary is: class Base { public: int getSomething() = 0; }; class DerivedA : public Base { public: int getSomething() { return 1; } } class DerivedB : public DerivedA { public: int getSomething() { return 1; } } I am wrapping these classes with a held_type of RefPtr<classType> except for the Base class because it is pure virtual. (this is a custom ref counting pointer; see thread above for details) I thought everything was good until I tried to wrap a factory class. The class can return any class type but it returns it through a pointer to the Base class like this: class Store { public: RefPtr<Base> getObject(int id); }; The problem wrapping this is that since I do not have a held_type registered for the base type as RefPtr<Base>, there is no to_python (by-value) converter found for C++ type: RefPtr<Base>. As an attempt to fix this I set the held type for Base to RefPtr<Base>, but this fails because pointer_holder.hpp line 179 needs to be able to alloate an object of the pointee type. Since it is pure virtual the compiler fails here. So my question is, when dealing with a polymorphic hierarchy like this is is possible to use a smart pointer as a held type for the most basic types? (ie. the pure virtual base). If not, does anyone have suggested workarounds for me to try? Thanks, Allen Note: One simplification I made above is that there is another pointer type in the mix. So getObject is actually returning a BasePtr that boost.python knows how to convert to a RefPtr<BasePtr>. See the previous thread for all the details.

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Exposing c++ classes with static arrays using Boost.Python and py++
by Abhi Oct. 3, 2006

Oct. 3, 2006

While running py++ on a class with a static array inside it, py++ generates Boost.Python bindings using a derived class for the original C++ class. Let me illustrate with the help of the following example: class AttributesTest { public: int staticIntArray[10]; }; Notice this class has an array inside it Running py++ generates the following code, with a wrapper class that derives from the AttributesTest class. struct AttributesTest_wrapper : AttributesTest, bp::wrapper< AttributesTest > { AttributesTest_wrapper(AttributesTest const & arg ) : AttributesTest( arg ) , bp::wrapper< AttributesTest >() {} AttributesTest_wrapper( ) : AttributesTest( ) , bp::wrapper< AttributesTest >() {} pyplusplus::containers::static_sized::array_1_t< int, 10 > pyplusplus_staticIntArray_wrapper(){ return pyplusplus::containers::static_sized::array_1_t< int, 10 >( staticIntArray ); } }; and BOOST_PYTHON_MODULE(PYPP_YodaPacketCommon){ if( true ){ typedef bp::class_< AttributesTest_wrapper > AttributesTest_exposer_t; AttributesTest_exposer_t AttributesTest_exposer = AttributesTest_exposer_t( "AttributesTest" ); bp::scope AttributesTest_scope( AttributesTest_exposer ); AttributesTest_exposer.def( bp::init< >()[bp::default_call_policies()] ); pyplusplus::containers::static_sized::register_array_1< int, 10, bp::default_call_policies >( "__array_1_int_10" ); AttributesTest_exposer.add_property( "staticIntArray" , bp::make_function( (pyplusplus::containers::static_sized::array_1_t< int, 10 > ( AttributesTest_wrapper::* )( ) )(&AttributesTest_wrapper::pyplusplus_staticIntArray_wrapper) , bp::with_custodian_and_ward_postcall< 0, 1, bp::default_call_policies >() ) );; Note that it maps the python name "AttributesTest" to the derived class AttributesTest_wrapper. Why not just keep it simple and rather than creating a derived class just map the variable "staticIntArray" via a global method, such as: .add_property( "staticIntArray" , bp::make_function( (&::someglobal_staticIntArray_wrapper) , bp::with_custodian_and_ward_postcall< 0, 1, bp::default_call_policies >() ) );; and define the someglobal_staticIntArray_wrapper method as: pyplusplus::containers::static_sized::array_1_t< int, 10 > someglobal_staticIntArray_wrapper(){ return pyplusplus::containers::static_sized::array_1_t< int, 10 >( staticIntArray ); } Is there any drawback with just mapping the array variable to a global method rather than mapping the whole class. thanks - Abhi

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Re: [C++-sig] (Philip Austin) PyArray_SimpleNewFromData(, PyArray_FLOAT, ) can't get c array in c extension?
by Qinfeng(Javen) Shi Sept. 30, 2006

Sept. 30, 2006

Hi Philip, I did as following, but it did not work. --------------------------------c extension----------------------- PyObject * testCreatArray() { float fArray[5] = {0,1,2,3,4}; PyArrayObject * c = (PyArrayObject*)PyArray_SimpleNewFromData(1,&m,PyArray_FLOAT,fArray); return (PyObject *)c; } ---------------------------result------------- >>> import hello >>> import numpy >>> list1 = range(5); >>> alist = hello.testCreatArray() >>> print alist [ 4.83833291e-34 -2.52239988e-05 -2.52361860e-05 0.00000000e+00 0.00000000e+00] >>> -- Qinfeng(Javen) Shi Research School of Information Sciences and Engineering Australian National University Locked Bag 8001 Canberra ACT 2601

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Another problem with split_module
by Ganssauge, Gottfried Sept. 29, 2006

Sept. 29, 2006

Hi Roman, as you may remember I'm generating function wrappers for functions expecting pointers to callback functions along with an instance pointer of type void. How do I make sure these wrappers are generated to the same file as the registration of the wrapper? Consider the following test: In single file mode this produces a working test module. In split file mode the WRAPPER_CODE is generated to test_wrapper.main.cpp whereas the registration is generated to test_wrapper_free_functions.pypp.cpp. test.hpp --- 8>< ------ ><8 --- void test (void *instance, void (*callback)(void *)); --- 8>< ------ ><8 --- test.py --- 8>< ------ ><8 --- # # Wrapper code for void test (void (*test)(void *)); # WRAPPER_CODE = """ void wrap_test_callback (void *instance) { boost::python::call<void> (reinterpret_cast<PyObject *> (instance)); static void test_wrapper (PyObject *callback) { test ( callback && (callback != Py_None)? wrap_test_callback: 0, callback); } """ import os from pyplusplus import \ module_builder from pygccxml.declarations.calldef import \ argument_t from pygccxml.declarations.cpptypes import \ dummy_type_t, \ pointer_t # PyObject * pyobject_type = pointer_t (dummy_type_t ("PyObject")) mb = module_builder.module_builder_t( ["test.hpp"] ) test = mb.free_function (name = "test") test.arguments = [ argument_t (name = "callback", type = pyobject_type) ] test.name = "test_wrapper" test.rename ("test") # this goes to the wrong source file :-( mb.add_declaration_code (WRAPPER_CODE) mb.build_code_creator( module_name='test_wrapper' ) mb.split_module( '.' ) --- 8>< ------ ><8 --- Cheers, Gottfried

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PyArray_SimpleNewFromData(, PyArray_FLOAT, ) can't get float c array in c extension?
by Qinfeng(Javen) Shi Sept. 29, 2006

Sept. 29, 2006

Dear All, I used PyArray_SimpleNewFromData to transfer a float c array data into numpy.ndarray. But it got the wrong array values. Any suggestion? Thanks in advance! ---------------------------hello.c------------- PyObject * testCreatArray() { float fArray[5] = {0,1,2,3,4}; intp m = 5; PyObject * c = PyArray_SimpleNewFromData(1,&m,PyArray_FLOAT,fArray); return c; } --------------------------result-------------------- >>> import hello >>> import numpy >>> list1 = range(5); >>> alist = hello.testCreatArray() >>> alist array([ 0.00000000e+00, -2.65695271e-05, 4.64483736e-34, 4.34402524e-44, -8.06840762e-06], dtype=float32) >>> -- Qinfeng(Javen) Shi Research School of Information Sciences and Engineering Australian National University Locked Bag 8001 Canberra ACT 2601

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[Graph] BGL python extension SVN version didn't link
by John Reid Sept. 29, 2006

Sept. 29, 2006

Hi, I tried to build the BGL from the latest SVN version and had some link errors to do with expat. My changes to fix these were the following: Add the following to the $(EXTRA_REQUIREMENTS) in bgl-python\build\Jamfile <define>XML_STATIC and add <define>XML_STATIC to the requirements for lib expat in bgl-python\vendor\expat-2.0.0\Jamfile I hope that helps someone or else someone can point out what I was doing wrong in the first place. FWIW I'm using MSVC8 with boost RC_1_34_0 Cheers, John.

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boost::python problem with std::string
by Sergey Makovkin Sept. 29, 2006

Sept. 29, 2006

Hello! I want to use Boost.python in my program but I have a problem. When I call a C++ function with std::string argument (or const std::string& ) from python, boost.python crashes! I don't know what to do and I hope you can help me. Here is a link to the source code which demonstrates the problem: http://www.powerfly.ru/bug.zip To compile it, you need MS Visual Studio 2005, Python 2.4 and Boost.Python 1.33 or later. -- Sergey A. Makovkin

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Problem with PyMethodDef and non-static functions
by Jon Kristensen Sept. 28, 2006

Sept. 28, 2006

Hello list! I'm using Python/C to be able to have simple Python scripts in my application. I was free of problems until I switched from using static and global functions to using non-static class methods: python.cpp:101: error: argument of type ‘PyObject* (Python::)(PyObject*, PyObject*)’ does not match ‘PyObject* (*)(PyObject*, PyObject*)’ After some time I understood that this was a problem that a little tweaking around wouldn't solve. So I want to ask you guys if you can describe how to get around this. I wouldn't want to add any additional dependencies such as SWIG or Boost. Please also note that I'm not that experienced with Python. And I want to keep this as clean/simple as possible! :-) Thanks in advance! -- Jon Kristensen

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Difference between old and new Boost.Python interface.
by Roman Yakovenko Sept. 28, 2006

Sept. 28, 2006

Good evening. I think I found a bug. I expose a class that defines operator+. If I use old Boost.Python interface for wrapper construction all works as expected. If I use new interface, then I can not invoke it. Please consider next code: namespace bp = boost::python; struct vector_new{ vector_new(){} vector_new operator+( const vector_new& x ) const; static const vector_new v_new; }; struct vector_old{ vector_old(){} vector_old operator+( const vector_old& x ) const; static const vector_old v_old; }; struct vector_new_wrapper : vector_new, bp::wrapper< vector_new > { vector_new_wrapper() : vector_new(), bp::wrapper< vector_new >() {} vector_new_wrapper(vector_new const & arg ) : vector_new(), bp::wrapper< vector_new >() {} }; struct vector_old_wrapper : vector_old, bp::wrapper< vector_old > { vector_old_wrapper(PyObject* ) : vector_old(), bp::wrapper< vector_old >() {} vector_old_wrapper(PyObject*, vector_old const & arg ) : vector_old(), bp::wrapper< vector_old >() {} }; BOOST_PYTHON_MODULE( operators_ext ){ bp::class_< vector_new_wrapper >( "vector_new" ) .def( bp::self + bp::self ) .def_readonly( "v_new", vector_new::v_new); bp::class_< vector_old, vector_old_wrapper >( "vector_old" ) .def( bp::self + bp::self ) .def_readonly( "v_old", vector_old::v_old ); } I can invoke operator+ for vector_old class, but I can not invoke operator+ for vector_new class: import operators_ext old = operators_ext.vector_old() tmp = old + operators_ext.vector_old.v_old #this will work new = operators_ext.vector_new() tmp = new + operators_ext.vector_new.v_new #Previous line will raise TypeError: #TypeError: unsupported operand type(s) for +: 'vector_new' and 'vector_new' I attached minimal test case that reproduce the problem to the mail. Thank you. -- Roman Yakovenko C++ Python language binding http://www.language-binding.net/

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please send me basic
by thilina sepala dahanayake Sept. 28, 2006

Sept. 28, 2006

I'm a new to c++, so I can't understand the hard things of c++.I want only basic of c++ I'll give you what I want - about Loops - what is arrys - what can i do from classes and objects - basic of oop I'll thank you very much if you send me above topics lectures thank you

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Boost.Python, MinGW, & ImportError
by Corey Wright Sept. 28, 2006

Sept. 28, 2006

this is in reference to the following postings to c++-sig and boost-users: 1. http://lists.boost.org/boost-users/2006/02/17367.php 2. http://mail.python.org/pipermail/c++-sig/2006-September/011202.html the summary: individuals, including myself, are seeing "ImportError: dynamic module does not define init function (inithello)" whenever trying to import a module compiled with mingw against boost.python, specifically the python examples and tutorial distributed with boost. the symptom: g++ fails to properly link whenever a null library search path (ie -L"") is specified (because maybe it stops parsing arguments there?). the cause: MINGW_BIN_DIRECTORY is null the short answer (for those newbies just trying to get through the tutorial/example and don't care to dive into the details of boost.build): bjam -sMINGW_BIN_DIRECTORY=C:\MinGW\bin (or where ever your mingw installation is) the longer answer: see attached patch the explanation: A. in gcc-tools.jam: 1. the gcc-Link-action contains -L"$(STDLIBPATH:T)" 2. STDLIBPATH is set based on following commands: a. flags gcc GCC_STDLIB_DIRECTORY : $(GCC_STDLIB_DIRECTORY) ; b. GCC_STDLIB_DIRECTORY ?= $(GCC_ROOT_DIRECTORY)$(SLASH)lib ; c. flags gcc STDLIBPATH : $(GCC_STDLIB_DIRECTORY) ; but when using mingw, the values in gcc-tools.jam are set... B. in mingw-tools.jam 1. local GCC_BIN_DIRECTORY = $(MINGW_BIN_DIRECTORY) ; 2. local GCC_STDLIB_DIRECTORY = $(MINGW_STDLIB_DIRECTORY) ; 3. flags mingw STDLIBPATH : $(GCC_BIN_DIRECTORY) ; so for mingw, STDLIBPATH is always composed of GCC_BIN_DIRECTORY (which is really MINGW_BIN_DIRECTORY). if you set MINGW_STDLIB_DIRECTORY, but not MINGW_BIN_DIRECTORY, you end up with -L"mingw_stdlib_directory" -L"". you must set MINGW_BIN_DIRECTORY to get rid of the null string or insure the null string in MINGW_BIN_DIRECTORY never gets added to STDLIBPATH. i successfully compiled boost.python without needing to set MINGW_BIN_DIRECTORY because the mingw tools are in my path and everything "just works". but if you try to compile python extensions (or at least the tutorial and examples), then things start mysteriously failing. i haven't had time to fully test my patch by building all of boost with it applied, but i'm currently in the process and last i looked bjam had compiled date and filesystem libraries, and was working on iostreams. thanks for boost.python and the mingw support (it feels liberating to compile free software, gratis & libre, with free software; and we'll overlook the operating system ;-). -- undefined(a)pobox.com

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Re: [C++-sig] (Philip Austin) numpy.ndarray did not match PyArrayObject
by Qinfeng(Javen) Shi Sept. 27, 2006

Sept. 27, 2006

Hi Philip, It is GREAT!. You code works! It is quite different from the numpybook 2006 or some online resources which I can find. Could please you provide some good stuffs about it here so that I can study it? Thanks you so much! Cheers! -- Qinfeng(Javen) Shi Research School of Information Sciences and Engineering Australian National University Locked Bag 8001 Canberra ACT 2601

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Py++ and caching
by Kirill Lapshin Sept. 27, 2006

Sept. 27, 2006

Hi Roman, Is there a way to not regenerate source code if cache is valid? I.e. currently cache saves us from running gccxml, but the whole code generation phase is still carried out even though it does not really changes anything (unless there was a change in driver .py script). Ideally I think what has to be done is: add an option to Py++ that will say these files are also a dependency (in addition to header(s) we are parsing with gccxml and the whole tree of headers #included from there); Py++ will run gccxml as before, only when needed, and will run code generation only if gccxml has been run or any additional dependencies have been modified since last time. We'll list driver script as additional dependency. This will reduce runtime of Py++ to almost zero if no changes are needed. I think I should be able to do something similar externally by tracking additional dependencies myself and asking cache prior to instantiating module builder. However I would imagine others may benefit from such functionality as well. Unless it already exists that is. :) Best regards, Kirill

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[boost][python2.5] "with" support
by Colin Grealy Sept. 27, 2006

Sept. 27, 2006

Now that python 2.5 has been released, are there any plans for adding support to bpl for the new language features? Specifically will there be support for the __enter__() and __exit__() special "with" methods? I think that most C++ developers would embrace this feature as it's close to the RAII idiom that modern C++ uses. Colin

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Re: [C++-sig] (David Abrahams)numpy.ndarray did not match PyArrayObject *
by Qinfeng(Javen) Shi Sept. 27, 2006

Sept. 27, 2006

Hi David, >boost::python::lvalue_from_pytype<extract_array_object,&PyArrayObject_Type>(); >struct extract_array_object > { > static PyArrayObject& execute(PyArrayObject& x) > { > return x; > } > }; > Yes, the very subtle trick at the bottom of my posting > "replace the indicated with the name of NumPy's python type object > for ndarray." Sorry, I don't get you. The Python type of the ndarray is PyArray_Type. InC, every ndarray is a pointer to a PyArrayObject structure. So what is the extract_array_object and what is PyArrayObject_Type? I tried boost::python::lvalue_from_pytype<PyArray_Type,&PyArrayObject>(); boost::python::lvalue_from_pytype<extract_array_object,&PyArray_Type>(); boost::python::lvalue_from_pytype<ndarray,&PyArray_Type>(); boost::python::lvalue_from_pytype<extract_array_object,&PyArrayObject_Type>(); boost::python::lvalue_from_pytype<extract_array_object,&ndarray>(); boost::python::lvalue_from_pytype<PyArray_Type,&PyArray_Type>(); boost::python::lvalue_from_pytype<ndarray,&ndarray>(); boost::python::lvalue_from_pytype<PyArray_Type,&ndarray>(); They all failed. Could you please tell me exactly? -- Qinfeng(Javen) Shi Research School of Information Sciences and Engineering Australian National University Locked Bag 8001 Canberra ACT 2601

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PyArg_ParseTuple() failed in parsing args
by Qinfeng(Javen) Shi Sept. 27, 2006

Sept. 27, 2006

Dear all, According the knowledge from http://numpy.scipy.org/numpydoc/numpy-13.html It seems when input args is numpy.ndarray, it uses PyArg_ParseTuple(args, "O!", &PyArray_Type, &array)) to convert PyObject* args into PyArrayObject* array. Then we can handle the array in c extension. But this PyArg_ParseTuple( ) failed(not crashed) when I used it in python environment(even when I put a real tuple into args). I have #define PY_ARRAY_UNIQUE_SYMBOL Javen and import_array(); and even #include "ufuncobject.h"; Is that possible to make it work? I guess I missed some subtle thing. Thanks! -- Qinfeng(Javen) Shi Research School of Information Sciences and Engineering Australian National University Locked Bag 8001 Canberra ACT 2601

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(no subject)
by Philip Austin Sept. 27, 2006

Sept. 27, 2006

Qinfeng(Javen) Shi writes: > Hi Philip and David > > What I really want to do is to access numpy.ndarray in c extension. I tried > 2 ways and Philip told me another possible way but I failed. The two appended files work for me with FC3 Linux -- Phil #define PY_ARRAY_UNIQUE_SYMBOL PyArrayHandle #include <boost/python.hpp> #include <numpy/noprefix.h> #include <iostream> namespace bp=boost::python; namespace ar=boost::python::numeric; //get a numeric array and double it void testFromPython(ar::array inValue){ double* dataPtr = (double*) PyArray_DATA(inValue.ptr()); std::cout << std::endl << "data values on c++ side: " << std::endl; intp theSize=PyArray_Size(inValue.ptr()); for(int i=0;i < theSize;++i){ std::cout << *(dataPtr + i) << std::endl; } } BOOST_PYTHON_MODULE(numtest_ext) { import_array(); ar::array::set_module_and_type("numpy", "ndarray"); std::string str1 = "Doc string for testFromPython\n"; def("testFromPython", testFromPython,str1.c_str()); } """when I run this script I get: ~/philprojects/pythonlibs/num_util phil@gull% python test.py data values on c++ side: 0 1 2 3 4 5 6 7 8 9 """ import numpy as n import numtest_ext as ne theArray=n.arange(10,dtype='Float64') ne.testFromPython(theArray)

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Re: [C++-sig] (Philip Austin) (David Abrahams)numpy.ndarray did not match PyArrayObject
by Qinfeng(Javen) Shi Sept. 27, 2006

Sept. 27, 2006

Hi Philip and David What I really want to do is to access numpy.ndarray in c extension. I tried 2 ways and Philip told me another possible way but I failed. ----------------------------------------------------- hello.c 1st way: void testArray(PyArrayObject * args) { } >>> hello.testArray(b) Traceback (most recent call last): File "<stdin>", line 1, in ? Boost.Python.ArgumentError: Python argument types in hello.testArray(numpy.ndarray) did not match C++ signature: testArray(PyArrayObject*) >>> ------------------------------------------------------hello.c 2nd way: void testArray(PyObject * args) { PyObject *input; PyArrayObject *array; if (!PyArg_ParseTuple(args, "O", &input)) printf("getting input failed!\n"); else printf("getting input sucess!\n"); } >>> import hello >>> import numpy >>> c = numpy.arange(25).reshape((5,5)) >>> d = hello.testArray(c); getting input failed! >>> d SystemError: new style getargs format but argument is not a tuple >>> then I tried adding following lines asPhilip told me to hello.cpp file. ------------------------------------------------hello.cpp namespace ar=boost::python::numeric; namespace bp=boost::python; import_array(); ar::array::set_module_and_type ("numpy", "ndarray"); It didn't crash but still had error. The interesting thing is that now running it twice would get two different error informations. ---------------------------------------------------error report in python >>> import hello >>> import numpy >>> a = numpy.arange(25).reshape((5,5)); >>> hello.testArray(a) // first time SystemError: new style getargs format but argument is not a tuple >>> hello.testArray(a) // second time args is array type! //it means PyArray_Check(args) successed this time. getting input failed! //PyArg_ParseTuple() failed but not crashed I am upset why I can't access numpy.ndarray. Any suggestion? Thanks! -- Qinfeng(Javen) Shi Research School of Information Sciences and Engineering Australian National University Locked Bag 8001 Canberra ACT 2601

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Re: [C++-sig] Py++ - problem withsplit_moduleandreturn_opaque_pointer-policy
by Ganssauge, Gottfried Sept. 26, 2006

Sept. 26, 2006

> -----Original Message----- > From: Ganssauge, Gottfried > Sent: Monday, September 25, 2006 12:39 PM > To: 'Development of Python/C++ integration' > Subject: RE: [C++-sig] Py++ - problem > withsplit_moduleandreturn_opaque_pointer-policy ... > > Also you don't have to add > > BOOST_PYTHON_OPAQUE_SPECIALIZED_TYPE_ID macro > To be exact: I _must_ not add ... > > > Py++ will generate one. > Indeed. > It works quite nice :-) One grain of salt though: Py++ will happily generate more than one if there are several functions returning the same opaque pointer type. This leads to a compilation error: redefinition of 'boost::python::type_info boost::python::type_id() [with T = <opaque pointee type>] In the following test the generated file test_opaque_free_functions.pypp.cpp will contain two instantiations of BOOST_PYTHON_OPAQUE_SPECIALIZED_TYPE_ID( opaque_ ). test.hpp ---8><---><8--- typedef struct opaque_ *opaque_pointer; opaque_pointer get_opaque(); opaque_pointer get2_opaque(); ---8><---><8--- test.py: ---8><---><8--- import os from pyplusplus import module_builder from pyplusplus.decl_wrappers import \ return_value_policy, \ return_opaque_pointer mb = module_builder.module_builder_t( ["test.hpp"] ) mb.free_function (name = "get_opaque").call_policies = \ return_value_policy (return_opaque_pointer) mb.free_function (name = "get2_opaque").call_policies = \ return_value_policy (return_opaque_pointer) mb.build_code_creator( module_name='test_opaque' ) mb.split_module( '.' ) ---8><---><8--- Cheers, Gottfried > > > > -- > > Roman Yakovenko > > C++ Python language binding > > http://www.language-binding.net/ > > _______________________________________________ > > C++-sig mailing list > > C++-sig(a)python.org > > http://mail.python.org/mailman/listinfo/c++-sig > > >

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to Philip Austin:Re: Stuck on accessing numpy.ndarray in c extension
by Qinfeng(Javen) Shi Sept. 26, 2006

Sept. 26, 2006

Hi Philip Austin, Thanks! I added following lines as you told me to hello.cpp file. It didn't crash but still had error. The interesting thing is that now running it twice would get two different error informations. /************hello.cpp**************/ namespace ar=boost::python::numeric; namespace bp=boost::python; import_array(); ar::array::set_module_and_type("numpy", "ndarray"); ########## error report########## >>> import hello >>> import numpy >>> a = numpy.arange(25).reshape((5,5)); >>> hello.testArray(a) // first time SystemError: new style getargs format but argument is not a tuple >>> hello.testArray(a) // second time args is array type! //it means PyArray_Check(args) successed this time. getting input failed! //PyArg_ParseTuple() failed but not crashed Any idea? -- Qinfeng(Javen) Shi Research School of Information Sciences and Engineering Australian National University Locked Bag 8001 Canberra ACT 2601

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Re: [C++-sig] numpy.ndarray did not match PyArrayObject *
by Qinfeng(Javen) Shi Sept. 26, 2006

Sept. 26, 2006

Hi David, I did what you told me. But it reported that PyArrayObject_Type undeclared though I included "arrayobject.h". Any important trick I missed? -- Qinfeng(Javen) Shi Research School of Information Sciences and Engineering Australian National University Locked Bag 8001 Canberra ACT 2601

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return PyObject* failed.
by Qinfeng(Javen) Shi Sept. 26, 2006

Sept. 26, 2006

Dear all, I write a c extension function to access python list. I can visit the list by PyObject* a, but failed when I tried to return PyObject* to python. Any suggestion will be appreciated. >>> list1 = range(5); >>> rlist = hello.testList(list1) 4 3 2 1 0 size:5 b is list type! # seems right now. >>> rlist # but actually it crashed when display the returned rlist Segmentation fault /**************c extension************/ static PyObject * testList(PyObject* a) { if(!(PyList_Check(a))) { printf("not list type!\n"); return NULL; } int num = PyList_Size(a); PyList_Reverse(a); // modify a. for(int i=0;i<num;i++) { printf("%d ",PyInt_AsLong(PyList_GetItem(a,i))); // print it out } printf("size:%d\n",num); PyObject * b = PyList_New(10); // create a new list b if (b == NULL) return NULL; if(!(PyList_Check(b))) // check b { printf("b is not list type!\n"); return NULL; } else { printf("b is list type!\n"); } /**********************works untill now******************/ return (PyObject *)b; /***********failed**/ // return b. in fact,if return a, it also crashed } // Boost Includes ============================================================== #include <boost/python.hpp> #include <boost/cstdint.hpp> // Includes ==================================================================== #include <hello.c> // Using ======================================================================= using namespace boost::python; // Declarations ================================================================ BOOST_PYTHON_OPAQUE_SPECIALIZED_TYPE_ID(PyObject) // Module ====================================================================== BOOST_PYTHON_MODULE(hello) { def("main", &main); def("testList", &testList, return_value_policy< return_opaque_pointer >()); } -- Qinfeng(Javen) Shi Research School of Information Sciences and Engineering Australian National University Locked Bag 8001 Canberra ACT 2601

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Re: [C++-sig] Stuck on accessing numpy.ndarray in c extension
by Qinfeng(Javen) Shi Sept. 25, 2006

Sept. 25, 2006

My boost::python exporting code is as following: // Boost Includes ============================================================== #include <boost/python.hpp> #include <boost/cstdint.hpp> // Includes ==================================================================== #include "hello.c" // Using ======================================================================= using namespace boost::python; // Declarations ================================================================ // Module ====================================================================== BOOST_PYTHON_MODULE(hello) { def("main", &main); def("testArray", &testArray); } -- Qinfeng(Javen) Shi Research School of Information Sciences and Engineering Australian National University Locked Bag 8001 Canberra ACT 2601

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