Mailman 3 February 2007 - Cplusplus-sig

How to import a boost::python dll in windows?
by ichijoji Aug. 5, 2011

Aug. 5, 2011

I'm trying to port some research code that uses boost::python to expose a library to python to windows, but I'm having trouble importing the dll into python. I'm compiling using msvc 2005 and using python 2.5, but when I try to import the module I get this: Traceback (most recent call last): File "main.py", line 1, in <module> import object File "c:\code\sge\code\scripts\object.py", line 1, in <module> import sge ImportError: No module named sge My module is named sge and I'm compiling to sge.dll. Is there some obvious reason why python wouldn't be able to find my dll? When I compile on linux into an so this code works fine. -- View this message in context: http://www.nabble.com/How-to-import-a-boost%3A%3Apython-dll-in-windows--tf3… Sent from the Python - c++-sig mailing list archive at Nabble.com.

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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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'iteritems', 'iterkeys' and 'itervalues' in dict
by Nindi Singh April 11, 2008

April 11, 2008

Apolgies for not putting the subject line in my last email. In the Boost.Python dict class there are methods 'iteritems', 'iterkeys' and 'itervalues' all returning objects. How exactly are you supposed to use these objects (iterators) ? ___________________________________________________________ Inbox full of spam? Get leading spam protection and 1GB storage with All New Yahoo! Mail. http://uk.docs.yahoo.com/nowyoucan.html

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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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Supplying a Python base class when wrapping a C++ class...
by Alex Mohr April 19, 2007

April 19, 2007

I'd like to wrap a C++ class and have the generated python wrapper class derive from a Python class. I know I can use bases<> to have my wrapped class derive from the class objects associated with the C++ types I specify in bases<>, but in this instance, I want to derive my wrapper class from a Python class that was not generated by boost.python. From looking at the code, it seems like it would be some work to add this capability. (Is anyone working on something like this?) As a workaround, does anyone know a way that I could perhaps hack this in after the Python class is created? That is, can I change the Python base classes of a Python class at runtime? Thanks, Alex

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Memory issues
by Paul Guse March 8, 2007

March 8, 2007

Hello. I have a few boost::python issues I need help with . Firstly, I'm getting some memory leaks by just including the boost libraries. (Dynamically linked dll, VS2005. Using boost to embed python in c++) >From what I gather this is still an outstanding issue with no, as of yet, solution? Is that correct? Second, this is also causing some issues as I need to free the resources allocated during the running of scripts. Specifically, I'm using the intrusive_ptr to wrap my own object's reference counting. When these objects are referenced in a python script the reference count is incremented, but not decremented when the script ends. As expected, this is causing some issues. Is there a way to clean up the variables allocated in a namespace? Or to effectively clear the main namespace? Thanks. Paul

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Importing into embedded Python
by Pertti Kellomäki Feb. 28, 2007

Feb. 28, 2007

I'm having problems importing modules containing Boost.Python produced bindings into an embedded Python interpreter. The following compiles into a module that loads fine into a standalone Python: testing.hh: ------------------ class A { }; ------------------ testing.cpp ------------------ #include <boost/python.hpp> #include "testing.hh" using namespace boost::python; BOOST_PYTHON_MODULE(testing) { class_<A>("A", init<>()) ; } ------------------- However, I get problems when I try to import the module into an embedded Python interpreter as follows: Py_Initialize(); PyRun_SimpleString("print 'Running Python'\n" "import testing\n" "print 'imported testing'\n" "a = testing.A() \n" "print 'a=', a \n"); The program outputs: Running Python imported testing Traceback (most recent call last): File "<string>", line 4, in ? AttributeError: 'module' object has no attribute 'A' I've googled around and found several pages describing similar problems, but so far no solutions. My setup is OS X 10.4, Python 2.4.4 and GCC 4.1.1 if that is of any help. -- Pertti

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make tuple of tuples in embedding python?
by ZiZi Zhao Feb. 28, 2007

Feb. 28, 2007

In Python/C API PyTuple can have different types of items. For example, pTuple = PyTuple_New(3); PyTuple_SetItem(pTuple, 0, pString1); PyTuple_SetItem(pTuple, 1, pString2); PyTuple_SetItem(pTuple, 2, pDict); I would like to know if I can make tuple of tuples for embedding Python in C++. For example, pTuple0 = PyTuple_New(3); pTuple1 = PyTuple_New(3); pTuple2 = PyTuple_New(3); pTupleOfTuple = PyTuple_New(3); PyTuple_SetItem(pTupleOfTuple, 0, pTuple0); PyTuple_SetItem(pTupleOfTuple, 1, pTuple1); PyTuple_SetItem(pTupleOfTuple, 2, pTuple2); It seems the code can be compiled. But, it would crash as long as it starts running without any output info. So, I could not know what is wrong. Thanks in Advance, ZZ

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Py++: Memory Ownership Passing
by Anand, Kumar Feb. 23, 2007

Feb. 23, 2007

How can I pass the memory ownership of a Derived class object (created in Python) to C++ though an interface that takes a Base class pointer? Does the function transformer in Py++ tackle this use case? ---------------------------------------------------------- Scenario: There is a class 'Base' and a derived class 'Derived' that extends from 'Base'. Both the classes have been exposed to Python. Class Base {}; Class Derived: public Base {}; bp::class_< Base > ("Base " ) .def( bp::init< >() ); bp::class_< Derived, bp::bases< Base > > ("Derived " ) .def( bp::init< >() ); Now I have a C++ function f that has also been exposed to python: void func (Base class * ptr) { //this function takes memory ownership of the passed object and does say delete ptr; } Assume all the above bindings have been exposed in the Boost_Test module and I have the following python code: import Boost_Test d = Boost_Test.Derived() Boost_Test.func(d); //This finally causes the interpreter to crash because of double deletion of object 'd' --------------------------------------------------------------- Specifying the 'held_type' for Derived class as std::auto_ptr and writing a wrapper function for 'func' that takes a std::auto_ptr<Base> as argument does not work. Thanks Kumar

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Error when importing Boost.Python exposed module into embedded Python
by Pertti Kellomäki Feb. 23, 2007

Feb. 23, 2007

I am trying to import a module containing exposed C++ classes into an embedded Python interpreter as follows: /* Initialize the Python interpreter */ Py_Initialize(); /* Execute some Python statements (in module __main__) */ PyRun_SimpleString("print 'Running Python'\n"); PyRun_SimpleString("import platform\n"); PyRun_SimpleString("print platform.python_version()\n"); PyRun_SimpleString("import TPEF\n"); This results in: Running Python 2.4.4 Fatal Python error: Interpreter not initialized (version mismatch?) The same module imports fine into a standalone Python: Python 2.4.4 (#3, Dec 21 2006, 12:46:16) [GCC 4.1.1] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> import platform >>> print platform.python_version() 2.4.4 >>> import TPEF Any ideas? Is there something simple that I am missing? -- Pertti

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