Mailman 3 May 2020 - Cplusplus-sig

Beginner How to debug a python class extracted in C++
by Carlos Duran May 16, 2020

May 16, 2020

Hi, I recently started a Boost Python project, https://mail.python.org/pipermail/cplusplus-sig/2020-May/017585.html but I need to debug my python classes extracted in C++ in the main program. The only referece that I find to this topic is in https://www.boost.org/doc/libs/1_73_0/libs/python/doc/html/faq/how_do_i_deb… How can I solve this? I am only using the gdb debugger. Thank you for your attention, Carlos

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Re: [C++-sig] Beginner - How to extract a Python Class that inherits from C++ Class
by Carlos Duran May 16, 2020

May 16, 2020

Hi, I find the solution, first of all I need to add the initializer on the C++ class import: class_<ComponentWrap, boost::shared_ptr<Component>, boost::noncopyable>("Component", init<>()) // I additionally added a Holder, but is not necessary. Then I add the base class initializer on the python class: class Derived(DemiWu.Component): def __init__(self): DemiWu.Component.__init__(self) I only find a problem, if a python class call the print function it doesn't work. Thanks, Carlos

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Re: [C++-sig] Cplusplus-sig Digest, Vol 125, Issue 5
by Carlos Duran May 14, 2020

May 14, 2020

Hi, I tried that solutions but they didn't work, furthermore, I thought that polymorphisim only works on pointers. I also tried changing to reference(Component&) and adding a HeldType in the import module: class_<ComponentWrap, Component* /*Or boost::shared_ptr<Component>*/, boost::noncopyable>("Component", init<>()) but all of this is futile. Thank you Carlos

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Re: [C++-sig] Cplusplus-sig Digest, Vol 125, Issue 5
by Lewis Evans May 14, 2020

May 14, 2020

I suggest (a) renaming as test.test is confusing, eg call the file/module test_file, and the class test_class (b) I think from your previous post that test.test() simply calls the constructor for class test, and this constructor is defined in python, returning an object not a pointer, so perhaps try extract<Component> not extract<Component*> Best Lewis Bayforest Technologies Limited 48 Dover St, Mayfair London W1S 4FF work1: +44 203 968 5167 email: lewis.evans(a)bayforest.ai web: https://bayforest.ai/ On Thu, May 14, 2020 at 5:00 PM <cplusplus-sig-request(a)python.org> wrote: > Send Cplusplus-sig mailing list submissions to > cplusplus-sig(a)python.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://mail.python.org/mailman/listinfo/cplusplus-sig > or, via email, send a message with subject or body 'help' to > cplusplus-sig-request(a)python.org > > You can reach the person managing the list at > cplusplus-sig-owner(a)python.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Cplusplus-sig digest..." > > > Today's Topics: > > 1. Re: Cplusplus-sig Digest, Vol 125, Issue 3 (Carlos Duran) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 13 May 2020 17:50:16 +0200 > From: Carlos Duran <carlos_wurt(a)zohomail.eu> > To: "cplusplus-sig" <cplusplus-sig(a)python.org> > Subject: Re: [C++-sig] Cplusplus-sig Digest, Vol 125, Issue 3 > Message-ID: > <1720ebab660.12aad1dbc94224.6884088036261319526(a)zohomail.eu> > Content-Type: text/plain; charset="utf-8" > > Hello again, > > > > I rewrite part of the code, but I didn't find my error. > > My new code is: > > cat ../src/DemiWu.cpp > > #include <boost/python.hpp> > > > > #include <DemiComponent.hpp> > > #include <DemiWu.hpp> > > #include <iostream> > > #include <string> > > > > using namespace boost::python; > > using namespace DemiWu; > > > > #if PY_MAJOR_VERSION >= 3 > > #?? define INIT_MODULE PyInit_DemiWu > > ??? extern "C" PyObject* INIT_MODULE(); > > #else > > #?? define INIT_MODULE initDemiwu > > ??? extern "C" void INIT_MODULE(); > > #endif > > > > int main() > > { > > ????? PyImport_AppendInittab((char*)"DemiWu", INIT_MODULE); > > ????? Py_Initialize(); > > ????? object main = import("__main__"); > > ????? object global = main.attr("__dict__"); > > ????? PySys_SetPath(L"."); > > ????? global["test"] = import("test"); // How can I check the import? > > > > ????? object funcObj = global["test"].attr("test"); > > ????? std::cout << std::boolalpha; > > ????? std::cout << funcObj.is_none() << "\n"; // funcObj.is_none() == false > > ????? object resultObj = funcObj(); > > ????? std::cout << resultObj.is_none() << "\n"; // resultObj.is_none() == > false > > > > ????? // I suppose that in "real" code I need to check every time I use > attr method. > > ????? extract<std::string> > exclass(funcObj.attr("__class__").attr("__name__")); > > ????? if(exclass.check()) > > ????? ????? std::cout << "test.test.__class__.__name__: " << exclass() << > "\n"; // exclass() == "class" > > ????? extract<std::string> > exclass2(resultObj.attr("__class__").attr("__name__")); > > ????? if(exclass2.check()) > > ????? ????? std::cout << "test.test().__class__.__name__: " << exclass2() > << "\n"; // exclass2() == "test" > > ????? extract<std::string> > exbase(funcObj.attr("__base__").attr("__name__")); > > ????? if(exbase.check()) > > ????? ????? std::cout << "test.test.__base__.__name__: " << exbase() << > "\n"; // exbase() == "Component" > > ????? // It seems that resultObj is correct, I think that I am using > extract<> function wrong. > > ????? extract<Component*> ex(resultObj); > > ????? if(ex.check()){ > > ????? ????? Component * const b=ex(); > > ????? ????? b->on_create(); ? > > ????? ????? std::cout << "SUCCESS\n"; > > ????? ????? return 0; > > ????? } else { > > ????? ????? std::cout << "FAIL\n"; // And again the program jumps here. > > ????? ????? return 1; > > ????? } > > } > > > > And the execution: > > ./DemiWu > > false > > false > > test.test.__class__.__name__: class > > test.test().__class__.__name__: test > > test.test.__base__.__name__: Component > > FAIL > > > > Thank you for your response > > > > Carlos >

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Re: [C++-sig] Cplusplus-sig Digest, Vol 125, Issue 3
by Carlos Duran May 13, 2020

May 13, 2020

Hello again, I rewrite part of the code, but I didn't find my error. My new code is: cat ../src/DemiWu.cpp #include <boost/python.hpp> #include <DemiComponent.hpp> #include <DemiWu.hpp> #include <iostream> #include <string> using namespace boost::python; using namespace DemiWu; #if PY_MAJOR_VERSION >= 3 # define INIT_MODULE PyInit_DemiWu extern "C" PyObject* INIT_MODULE(); #else # define INIT_MODULE initDemiwu extern "C" void INIT_MODULE(); #endif int main() { PyImport_AppendInittab((char*)"DemiWu", INIT_MODULE); Py_Initialize(); object main = import("__main__"); object global = main.attr("__dict__"); PySys_SetPath(L"."); global["test"] = import("test"); // How can I check the import? object funcObj = global["test"].attr("test"); std::cout << std::boolalpha; std::cout << funcObj.is_none() << "\n"; // funcObj.is_none() == false object resultObj = funcObj(); std::cout << resultObj.is_none() << "\n"; // resultObj.is_none() == false // I suppose that in "real" code I need to check every time I use attr method. extract<std::string> exclass(funcObj.attr("__class__").attr("__name__")); if(exclass.check()) std::cout << "test.test.__class__.__name__: " << exclass() << "\n"; // exclass() == "class" extract<std::string> exclass2(resultObj.attr("__class__").attr("__name__")); if(exclass2.check()) std::cout << "test.test().__class__.__name__: " << exclass2() << "\n"; // exclass2() == "test" extract<std::string> exbase(funcObj.attr("__base__").attr("__name__")); if(exbase.check()) std::cout << "test.test.__base__.__name__: " << exbase() << "\n"; // exbase() == "Component" // It seems that resultObj is correct, I think that I am using extract<> function wrong. extract<Component*> ex(resultObj); if(ex.check()){ Component * const b=ex(); b->on_create(); std::cout << "SUCCESS\n"; return 0; } else { std::cout << "FAIL\n"; // And again the program jumps here. return 1; } } And the execution: ./DemiWu false false test.test.__class__.__name__: class test.test().__class__.__name__: test test.test.__base__.__name__: Component FAIL Thank you for your response Carlos

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Re: [C++-sig] Cplusplus-sig Digest, Vol 125, Issue 3
by Lewis Evans May 13, 2020

May 13, 2020

Hello, I suggest to avoid eval, in main() instead, after "import test" in main(): funcObj = global["test"].attr("test") // assuming your global["test"] is a successfully imported module resultObj = funcObj() then check resultObj: as well as extract-and-check, you can query repr/str, and is_none(), and check attributes __class__ and __class__.__name__ in boost-python say someObject.attr("attributeNameHere") Best Lewis Bayforest Technologies Limited 48 Dover St, Mayfair London W1S 4FF work1: +44 203 968 5167 email: lewis.evans(a)bayforest.ai web: https://bayforest.ai/ On Tue, May 12, 2020 at 5:00 PM <cplusplus-sig-request(a)python.org> wrote: > Send Cplusplus-sig mailing list submissions to > cplusplus-sig(a)python.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://mail.python.org/mailman/listinfo/cplusplus-sig > or, via email, send a message with subject or body 'help' to > cplusplus-sig-request(a)python.org > > You can reach the person managing the list at > cplusplus-sig-owner(a)python.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Cplusplus-sig digest..." > > > Today's Topics: > > 1. Beginner - How to extract a Python Class that inherits from > C++ Class (Carlos Duran) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Tue, 12 May 2020 12:11:36 +0200 > From: Carlos Duran <carlos_wurt(a)zohomail.eu> > To: "cplusplus-sig" <cplusplus-sig(a)python.org> > Subject: [C++-sig] Beginner - How to extract a Python Class that > inherits from C++ Class > Message-ID: > <172085e498d.e3349fd230005.5688831514627266454(a)zohomail.eu> > Content-Type: text/plain; charset="utf-8" > > Hi, > > > > I was being researching the Boost.Python library, this archive and > stackoverflow but I couldn't find the correct answer. > > > > I tried the following: > -First: I created the C++ Class. > -------------------------------------------------------------------------- > > user@host ~/ProjectFolder: cat lib/DemiComponent.hpp > > #pragma once > > #include <boost/python.hpp> > > > > namespace DemiWu > > { > > ?? ?class Component > > ?? ?{ > > ?? ??? ?public: > > ?? ??? ?Component(){}; > > ?? ??? ?virtual ~Component(){}; > > ?? ??? ?virtual void on_create(){}; > > ?? ?}; > > > > ?? ?class ComponentWrap : public Component, public > boost::python::wrapper<Component> > > ?? ?{ > > ?? ??? ?public: > > ?? ??? ?void empty(){} > > ?? ??? ?virtual void on_create() > > ?? ??? ?{ > > ?? ??? ??? ?this->get_override("on_create")(); > > ?? ??? ?} > > ?? ?}; > > > > ?? ?void import_component() > > ?? ?{ > > ?? ??? ?using namespace DemiWu; > > ?? ? ?? ?using namespace boost::python; > > ?? ??? ?class_<ComponentWrap, boost::noncopyable>("Component") > > ?? ??? ??? ?.def("on_create", &Component::on_create, > &ComponentWrap::empty); > > > > ?? ?}; > > }; > > -------------------------------------------------------------------------- > > > > -Second: I exported to Python > > -------------------------------------------------------------------------- > > user@host ~/ProjectFolder: cat lib/DemiWu.hpp > > #pragma once > > #include <boost/python.hpp> > > #include <DemiComponent.hpp> > > > > BOOST_PYTHON_MODULE(DemiWu) > > { > > ?? ?DemiWu::import_component(); > > } > > -------------------------------------------------------------------------- > > ?cat lib/DemiWu.cpp > > #include <DemiWu.hpp> > > --------------------------- > > > > -Third: I used Meson to compile, but I think that is not important. The > module works on python3 interpreter. > > -------------------------------------------------------------------------- > > > > -Fourth: I wrote a Python Class that inherit form the C++ Class > DemiWu::Component. > > -------------------------------------------------------------------------- > > user@host ~/ProjectFolder: cat build/test.py > > import DemiWu > > > > class test(DemiWu.Component): > > ??? def __init__(self): > > ??????? self.x = 10; > > ??????? self.y = 20; > > > > ??? def on_create(self): > > ??????? print("(",self.x, ",",self.y,")", sep="") > > ??????? self.x = self.x + 1 > > ??????? self.y = self.y + 1 > > -------------------------------------------------------------------------- > > > > Fifth: I write a program that extracts the test Python Class. > > -------------------------------------------------------------------------- > > user@host ~/ProjectFolder: cat src/DemiWu.cpp > > #include <boost/python.hpp> > > #include <DemiComponent.hpp> > > #include <DemiWu.hpp> > > #include <iostream> > > using namespace boost::python; > > using namespace DemiWu; > > > > int main() > > { > > ?? ?PyImport_AppendInittab("DemiWu", PyInit_DemiWu); > > ?? ?Py_Initialize(); > > ?? ?object main = import("__main__"); > > ?? ??? ?object global = main.attr("__dict__"); > > ?? ?PySys_SetPath(L"."); > > ?? ?global["test"] = import("test"); > > ?? ?object obj = eval("test.test()", global); > > ?? ?extract<Component*> ex(obj); > > ?? ?if(ex.check()){ > > ??? ??? ?Component* b=ex(); > > ????? ?? b->on_create();? > > ?? ??? ? std::cout << "SUCCESS\n"; > > ?? ??? ? return 0; > > ?? ?} else { > > ?? ??? ?std::cout << "FAIL\n"; > > ?? ??? ?return 1; > > ?? ?} > > } > > -------------------------------------------------------------------------- > > > > Sixth: Compile the program successfully. > > -------------------------------------------------------------------------- > > > > Seventh: Execute and... the output is always "FAIL". > > -------------------------------------------------------------------------- > > > > How can I fix it? What did I miss? > > > > Thank you for your attention, > > > > Carlos > > > > PS: Sorry for the format of the mail, but I can't express on English well. >

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Beginner - How to extract a Python Class that inherits from C++ Class
by Carlos Duran May 12, 2020

May 12, 2020

Hi, I was being researching the Boost.Python library, this archive and stackoverflow but I couldn't find the correct answer. I tried the following: -First: I created the C++ Class. -------------------------------------------------------------------------- user@host ~/ProjectFolder: cat lib/DemiComponent.hpp #pragma once #include <boost/python.hpp> namespace DemiWu { class Component { public: Component(){}; virtual ~Component(){}; virtual void on_create(){}; }; class ComponentWrap : public Component, public boost::python::wrapper<Component> { public: void empty(){} virtual void on_create() { this->get_override("on_create")(); } }; void import_component() { using namespace DemiWu; using namespace boost::python; class_<ComponentWrap, boost::noncopyable>("Component") .def("on_create", &Component::on_create, &ComponentWrap::empty); }; }; -------------------------------------------------------------------------- -Second: I exported to Python -------------------------------------------------------------------------- user@host ~/ProjectFolder: cat lib/DemiWu.hpp #pragma once #include <boost/python.hpp> #include <DemiComponent.hpp> BOOST_PYTHON_MODULE(DemiWu) { DemiWu::import_component(); } -------------------------------------------------------------------------- cat lib/DemiWu.cpp #include <DemiWu.hpp> --------------------------- -Third: I used Meson to compile, but I think that is not important. The module works on python3 interpreter. -------------------------------------------------------------------------- -Fourth: I wrote a Python Class that inherit form the C++ Class DemiWu::Component. -------------------------------------------------------------------------- user@host ~/ProjectFolder: cat build/test.py import DemiWu class test(DemiWu.Component): def __init__(self): self.x = 10; self.y = 20; def on_create(self): print("(",self.x, ",",self.y,")", sep="") self.x = self.x + 1 self.y = self.y + 1 -------------------------------------------------------------------------- Fifth: I write a program that extracts the test Python Class. -------------------------------------------------------------------------- user@host ~/ProjectFolder: cat src/DemiWu.cpp #include <boost/python.hpp> #include <DemiComponent.hpp> #include <DemiWu.hpp> #include <iostream> using namespace boost::python; using namespace DemiWu; int main() { PyImport_AppendInittab("DemiWu", PyInit_DemiWu); Py_Initialize(); object main = import("__main__"); object global = main.attr("__dict__"); PySys_SetPath(L"."); global["test"] = import("test"); object obj = eval("test.test()", global); extract<Component*> ex(obj); if(ex.check()){ Component* b=ex(); b->on_create(); std::cout << "SUCCESS\n"; return 0; } else { std::cout << "FAIL\n"; return 1; } } -------------------------------------------------------------------------- Sixth: Compile the program successfully. -------------------------------------------------------------------------- Seventh: Execute and... the output is always "FAIL". -------------------------------------------------------------------------- How can I fix it? What did I miss? Thank you for your attention, Carlos PS: Sorry for the format of the mail, but I can't express on English well.

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Re: [C++-sig] Compiling boost python
by Lewis Evans May 1, 2020

May 1, 2020

We build boost-python using a simple setup: 1. build boost according to its own instructions 2. cmake to build our C++, using find_package for python and boost libraries we use the latest cmake, find_package with exact required components I personally found bjam tricky to use (very few examples or search results for problems), whereas cmake/gnumake are standard and widely used. Lewis Bayforest Technologies Limited 48 Dover St, Mayfair London W1S 4FF work1: +44 203 968 5167 email: lewis.evans(a)bayforest.ai web: https://bayforest.ai/ On Thu, Apr 30, 2020 at 10:27 PM <cplusplus-sig-request(a)python.org> wrote: > Send Cplusplus-sig mailing list submissions to > cplusplus-sig(a)python.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://mail.python.org/mailman/listinfo/cplusplus-sig > or, via email, send a message with subject or body 'help' to > cplusplus-sig-request(a)python.org > > You can reach the person managing the list at > cplusplus-sig-owner(a)python.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Cplusplus-sig digest..." > > > Today's Topics: > > 1. Re: Compiling boost python (Axel Huebl) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 30 Apr 2020 14:21:40 -0700 > From: Axel Huebl <a.huebl(a)hzdr.de> > To: Development of Python/C++ integration <cplusplus-sig(a)python.org> > Subject: Re: [C++-sig] Compiling boost python > Message-ID: <6C53894D-D06A-4F18-AE8E-0C479DA9B201(a)hzdr.de> > Content-Type: text/plain; charset="utf-8" > > Hi, > > Check out the bazel example or the plain build with setuptools: > > https://github.com/pybind/ > https://github.com/pybind/python_example > > Axel > > On April 30, 2020 9:05:39 AM PDT, Andrew Voelkel < > jandyman.voelkel(a)gmail.com> wrote: > >The examples all use cmake, and there is a cmake extension for pybind11 > >that takes care of a number of things for you. From the docs: > > > >For C++ codebases that have an existing CMake-based build system, a > >Python extension module can be created with just a few lines of code: > >cmake_minimum_required(VERSION 2.8.12) > >project(example) > > > >add_subdirectory(pybind11) > >pybind11_add_module(example example.cpp) > > > >More here: > > > > > https://pybind11.readthedocs.io/en/stable/compiling.html#building-with-cmake > > > > > >From: Cplusplus-sig > ><cplusplus-sig-bounces+jandyman.voelkel=gmail.com(a)python.org> on behalf > >of Alain O' Miniussi <alain.miniussi(a)oca.eu> > >Reply-To: Development of Python/C++ integration > ><cplusplus-sig(a)python.org> > >Date: Thursday, April 30, 2020 at 8:30 AM > >To: Development of Python/C++ integration <cplusplus-sig(a)python.org> > >Subject: Re: [C++-sig] Compiling boost python > > > >But having one more lib outside boost means one more dependency. > > > >The sad thing is that dropping support for "the oldest and buggiest of > >compiler specimens" in Boost would be rational to do, there are plenty > >of old Boost releases for those. > >How the cmake support for pybind ? > > > >----- On 29 Avr 20, at 20:09, Andrew Voelkel > ><jandyman.voelkel(a)gmail.com> wrote: > > > >This blurb might help with that question: > > > >The main issue with Boost.Python?and the reason for creating such a > >similar project?is Boost. Boost is an enormously large and complex > >suite of utility libraries that works with almost every C++ compiler in > >existence. This compatibility has its cost: arcane template tricks and > >workarounds are necessary to support the oldest and buggiest of > >compiler specimens. Now that C++11-compatible compilers are widely > >available, this heavy machinery has become an excessively large and > >unnecessary dependency. Think of this library as a tiny self-contained > >version of Boost.Python with everything stripped away that isn?t > >relevant for binding generation. Without comments, the core header > >files only require ~4K lines of code and depend on Python (2.7 or 3.x, > >or PyPy2.7 >= 5.7) and the C++ standard library. This compact > >implementation was possible thanks to some of the new C++11 language > >features (specifically: tuples, lambda functions and variadic > >templates). Since its creation, this library has grown beyond > >Boost.Python in many ways, leading to dramatically simpler binding code > >in many common situations. > > > > > > * Andy > > > >From: Cplusplus-sig > ><cplusplus-sig-bounces+jandyman.voelkel=gmail.com(a)python.org> on behalf > >of Torsten Kn?ppel <brumfessor(a)gmx.net> > >Reply-To: Development of Python/C++ integration > ><cplusplus-sig(a)python.org> > >Date: Wednesday, April 29, 2020 at 8:15 AM > >To: Development of Python/C++ integration <cplusplus-sig(a)python.org> > >Subject: Re: [C++-sig] Re: Compiling boost python > > > >Hi Andy, > > > >thanks for the quick reply. I only came across pybind recently when I > >was encountering some dependency issues with > >boost.python<http://boost.python> and looked for an alternative. It > >looks really useful, but I hesitated to make the switch - but I think I > >will do it sooner or later. Maybe one question regarding pybind - is it > >easy to create bindings for different Python versions? > >Am 29.04.20, 16:42 schrieb Andrew Voelkel <jandyman.voelkel(a)gmail.com>: > >Have you considered using pybind11? It?s the same basic idea as > >boost.python, but it is cleaner, much better supported and documented, > >and has a large user community. I just discovered this lately, have > >been using it, and I?m thrilled with it. The only catch is that you > >need to be compiling with at least a C++11 compiler, but that is a > >pretty low bar these days. > > > > > > * Andy > > > >From: Cplusplus-sig > ><cplusplus-sig-bounces+jandyman.voelkel=gmail.com(a)python.org> on behalf > >of Torsten Kn?ppel <brumfessor(a)gmx.net> > >Reply-To: Development of Python/C++ integration > ><cplusplus-sig(a)python.org> > >Date: Wednesday, April 29, 2020 at 7:34 AM > >To: "cplusplus-sig(a)python.org" <cplusplus-sig(a)python.org> > >Subject: [C++-sig] Compiling boost python > > > >Dear all, > > > >I'm trying to compile boost.python with a version of python, that I've > >downloaded and built myself. > >Is the "No-install quickstart"-page > >( > https://www.boost.org/doc/libs/1_73_0/libs/python/doc/html/building/no_inst… > ) > >still updated, because some of the links are broken and > >I honestly don't understand what is going on there. > >Some questions that I have: > >- What is the bjam "build driver"? When I go to Section 5 of the boost > >Getting Started page - they mention something about an easy install > >option and another one for custom binaries. > > The entire page mentions neither bjam, nor "build driver". > >- I manage to build boost, by first running the bootstrap script and > >then calling b2 - if I select e.g. graph - it is built and copied into > >the correct directory, that I've specified. However, > > it doesn't work with my own Python folder. > > I wrote a small script to automate all steps: > > > >#wget > >https://dl.bintray.com/boostorg/release/1.73.0/source/boost_1_73_0.tar.gz > >#tar -xvf boost_1_73_0.tar.gz > >cd boost_1_73_0 > >./bootstrap.sh --prefix=../build_boost --with-libraries=python > >-with-python-root=../Python-3.6.10 --with-python-version=3.6 > >./b2 install -d+2 > >echo "using python : : ../Python-3.6.10/python ;" > user-config.jam > > > >My folder structure is as follows: > > > >buildBoost.sh (the script above) > >/Python-3.6.10 (contains the python source code and binaries that I've > >build myself) > > /boost_1_73_0 (boost source code as downloaded by the script) > > /build_boost (output folder as specified by prefix) > > > >When do I need to write this user-config.jam file? What are the > >compilation scripts looking for - can this process be debugged? > >I also have boost installed via apt - now I think that everytime I call > >b2 or bjam it uses > >the global versions of these programs, instead of the ones contained in > >the boost-directory I'm compiling - is that an issue? > > > >Thanks in advance. > >torsten > >_______________________________________________ Cplusplus-sig mailing > >list Cplusplus-sig(a)python.org > >https://mail.python.org/mailman/listinfo/cplusplus-sig > > > >_______________________________________________ > >Cplusplus-sig mailing list > >Cplusplus-sig(a)python.org > >https://mail.python.org/mailman/listinfo/cplusplus-sig > > -- > Sent from my smartphone. > Please excuse my brevity. >

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Passing vector as argument to python function using boost python
by deepansh May 1, 2020

May 1, 2020

I followed https://riptutorial.com/boost/example/25280/wrapping-std--vector-in-boost-p… but how to include vector_indexing_suite for passing vector as argument? I am getting the error: No Python class registered for C++ class std::vector > when running the code: BOOST_PYTHON_MODULE(Strat) { bp::class_<std::vector<long> >("Long_vec") .def(bp::vector_indexing_suite<std::vector<long> >()) ; bp::class_<PyStrat, boost::noncopyable>("Strat") .def("gen_fibonacci", &Strat::gen_fibonacci) ; } int main() { try { Py_Initialize(); // register the python module we created, so our script can import it PyImport_AppendInittab("Strat",&initStrat); //PyImport_AppendInittab("StrategyFramework", &initStrategyFramework); // import the __main__ module and obtain the globals dict bp::object main = bp::import("__main__"); bp::object globals = main.attr("__dict__"); // import our strategy.py file bp::object module = import("Strat", "./python_plugins/strat1.py", globals); // obtain the strategy class and instantiate one bp::object Strategy = module.attr("Strategy"); bp::object strategy = Strategy(); std::cout<<"not here"; Helper a; strategy.attr("gen_fibonacci")(boost::ref(a.v),1,100); long ans=a.sum_series(a.v); std::cout<<"done"; return 0; } catch(const bp::error_already_set&) { std::cerr << ">>> Error! Uncaught exception:\n"; PyErr_Print(); return 1; } } what am i doing wrong? strat1.py: from Strat import * class Strategy: def gen_fibonacci(self,l,ind,n): num = 3 t1 = 0 t2 = 1 nextTerm = 0 i=1 if ind==1: l.append(0) l.append(1) i=3 if ind==2: l.append(1) i=2 while i<n: nextTerm=t1+t2 t1=t2 t2=nextTerm if num>=ind: i=i+1 l.append(nextTerm) num=num+1 return 0 -- Sent from: http://boost.2283326.n4.nabble.com/Python-c-sig-f2696818.html

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