Mailman 3 March 2005 - Cplusplus-sig

Sub-modules
by Eric Jardim March 28, 2005

March 28, 2005

Hi, is it possible to define python sub-modules with boost.python? BOOST_PYTHON_MODULE(out) { BOOST_PYTHON_MODULE(in) { def("f", &f) } } --- >>> import out.in >>> out.in.f() Or something like that? What is the correct way of doing that? I thought that if we could do it separate BOOST_PYTHON_MODULE(out) { } (out.cpp -> out.so) BOOST_PYTHON_MODULE(in) { def("f", &f) } (in.cpp -> in.so) and place them like .../site-packages/ out/ __init__.py out.so in/ __init__.py in.so Anyway, what is the "correct" way of doing that? [Eric Jardim]

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Automatically convert Python objects to constant pointer / const struct s *s?
by Daniel Holth March 27, 2005

March 27, 2005

I'm wrapping some functions that look like this: struct data_only { int foo; int bar; int baz[40]; } int use_data(int a, const struct data_only *b) { // ... } I have no trouble converting the struct into Python but I'm unclear how to convert it back. I would like to be able to substitute a dictionary or class with the same properties also, rather than require an instance of that struct. How should I register from-python convertors for this purpose? Thanks, Daniel Holth

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Re: [C++-sig] Python 2.4 timeline?
by Ralf W. Grosse-Kunstleve March 27, 2005

March 27, 2005

--- Clay Culver <clay(a)idleengineer.net> wrote: > Is there any timeline or expected date for Python 2.4 to be officially > supported? I could compile it myself but I would rather wait until it's > supported to upgrade. Boost.Python works with Python 2.4. This was true even before 2.4 was officially released. I've also tested the latest 2.4.1c2 without running into any problems. Cheers, Ralf __________________________________ Do you Yahoo!? Take Yahoo! Mail with you! Get it on your mobile phone. http://mobile.yahoo.com/maildemo

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Python 2.4 timeline?
by Clay Culver March 26, 2005

March 26, 2005

Is there any timeline or expected date for Python 2.4 to be officially supported? I could compile it myself but I would rather wait until it's supported to upgrade. Thanks, Clay

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Wrapping a simple class
by Eric Jardim March 26, 2005

March 26, 2005

Hi, I have read the paper of Boost.Python and the tutorial, and started trying wrapping some handy-made classes to learn how to use Boost.Python with real APIs. My question is simple (I think :) ). Suppose I have this class below: ### a.h ### class A { A* _parent; char* _name; public: A(A* parent=0, const char* name); const char* getName() const; void setName(const char* name); A* getParent() const; }; ### a.cpp ### #include "hello.h" #include <string.h> A::A(A* parent, const char* name) { _parent = parent; setName(name); } const char* A::getName() const { return _name; } void A::setName(const char* name) { strcpy(_name, name); } A* A::getParent() const { return _parent; } --- The example is simple enough, besides that some functions deals with char* and A* pointers. Reading the turorial and paper I've noticed that the arguments and return values are always ints, bools, doubles and even std::strings, but never custom objects references/pointers. I have tried (trivial) examples before (no pointers) and it worked Ok. But trying this example things do not worked as I expected. I tried exposing this class with something like: #include <hello.h> BOOST_PYTHON_MODULE(hello) { class_<A>("A", init<A*, const char*>()) .add_property("name", &A::getName, &A::setName) // readwrite property .add_property("parent", &A::getParent) // readonly property ; } Here is my Python script that uses the wrapper: ### hello.py ### import hello a = hello.A(None, 'a') print a, a.name, a.parent b = hello.A(a, 'b') print b, b.name, b.parent --- The expected behaviour is that the "a" object has no parent, so I pass a None (which I suppose that is converted to 0 in C++), and a "b" object has "a" as its parent. The expected output is: >>> import hello >>> a = hello.A(None, 'a') >>> print a, a.name, a.parent <hello.A object at 0x11111111> a None >>> b = hello.A(a, 'b') >>> print b, b.name, b.parent <hello.A object at 0x22222222> b <hello.A object at 0x11111111> --- Thanks in advance. I think if I understand this example things will be much clearer from here on... [Eric Jardim]

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wrapping class with pure virtual function & non-default constructor
by Faheem Mitha March 26, 2005

March 26, 2005

Hi, Please consider the following variation of the example in the tutorial. The main difference here is that the class that is being wrapped has a non-default destructor. Without a destructor declared in BaseWrap, this gives the error error: base `World' with only non-default constructor in class without a constructor Adding a default constructor to the wrapper class makes the error go away, eg. BaseWrap():Base(0){} I can't find an example of this anywhere. I've looked at the docs, but don't understand what is going on well enough. So, I'm asking here. Is this Ok, and can I use any default constructor for the wrapper class without it making any difference? One other thing. Am I correct in thinking that wrapping the base class in this fashion is necessary if I want to wrap the derived classes? Clarifications appreciated. I'm not subscribed, so please cc me at faheem(a)email.unc.edu if possible. Thanks. Faheem. ************************************************************************* #include <boost/python.hpp> #include <boost/python/module.hpp> #include <boost/python/class.hpp> #include <boost/python/return_value_policy.hpp> #include <boost/python/manage_new_object.hpp> #include <boost/python/reference_existing_object.hpp> #include <boost/python/pure_virtual.hpp> #include <boost/python/wrapper.hpp> #include <boost/python/def.hpp> #include <boost/python/call.hpp> #include <boost/utility.hpp> #include <iostream> #include <string> using namespace boost::python; struct Base { int data; Base(int _data):data(_data){} virtual ~Base() {} virtual int f() = 0; }; struct BaseWrap : Base, wrapper<Base> { BaseWrap():Base(0){} int f() { return this->get_override("f")(); } }; BOOST_PYTHON_MODULE_INIT(polymorphism2_ext) { class_<BaseWrap, boost::noncopyable>("Base") .def("f", pure_virtual(&Base::f)) ; }

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Re: [C++-sig] boost::python (boost-1_32) and gcc 4.0 (compiler error)
by Ralf W. Grosse-Kunstleve March 25, 2005

March 25, 2005

--- Lothar Werzinger <lothar(a)xcerla.com> wrote: > boost::python does not compile with gcc 4.0 (4.0-20050213). > Has anyone successfully used boost::python and gcc 4.0? Are there patches to > make it work? I tried with - the latest boost CVS - gcc version 4.0.0 20050324 (prerelease) Most (i.e. all I tried) Boost.Python tests compile and even run. However, our applications are almost completely broken because of a show-stopper bug in gcc: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19317 Given this bug I am amazed that all Boost.Python tests run. In general I am afraid the current gcc 4.0.0 is unsuitable for real-world applications. :( Ralf __________________________________ Do you Yahoo!? Make Yahoo! your home page http://www.yahoo.com/r/hs

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return_internal_reference or return_value_policy
by chencc＠csie.nctu.edu.tw March 24, 2005

March 24, 2005

Hi all: I have a small C code, and want to extent it using boost.python. This code return pointer and take pointer as argument. I try to use return_internal_reference or return_value_policy with manage_new_object. Then compiler can\'t give me a object code. I can\'t read these message, does any people can help me ??? I use the bjam in example/tutorial/Jamfile with modify in unix #include <boost/python.hpp> using namespace boost::python; typedef unsigned int *Handle; Handle cr(inti, Handle s) { Handle r; r = new unsigned int[i]; for ( int j = 0; j < i; j++) r[j] = s[j]; return r; } void dr(Handle s) { delete [] s; } void set(int i, Handle r) { r[i] = (unsigned int) i; } int get(int i, Handle r) { return r[i]; } BOOST_PYTHON_MODULE(my) { def(\"cr\",cr,return_value_policy< manage_new_object> () ); // def(\"cr\",cr,return_internal_reference<2> () ); def(\"dr\",dr); def(\"set\",set); def(\"get\",get); } }

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Herringshaw??
by Bob Battel March 23, 2005

March 23, 2005

Is this you? If you are the same Chris Herringshaw that I hung around with in Cass City, please reply. If not, I apologize for having wasted your time. Bob Battel Bob Battel Extension Educator, Farm Management Serving Northwest Lower Michigan Osceola MSU Extension 301 W. Upton Ave. Reed City, MI 49677 Phone: 231.832.7342 Please make a note new e-mail address: battelro(a)msu.edu

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boost::python (boost-1_32) and gcc 4.0 (compiler error)
by Lothar Werzinger March 23, 2005

March 23, 2005

Hi, boost::python does not compile with gcc 4.0 (4.0-20050213). Has anyone successfully used boost::python and gcc 4.0? Are there patches to make it work? The error given is: /opt2/boost/include/boost-1_32/boost/mpl/aux_/integral_wrapper.hpp:72: error: template argument 2 is invalid /opt2/boost/include/boost-1_32/boost/mpl/aux_/integral_wrapper.hpp:73: error: template argument 2 is invalid Here's the complete compiler output: /opt2/GNU/bin/g++-4.0-20050213 -O0 -g -D_REENTRANT -DACE_HAS_AIO_CALLS -DACE_USE_RCSID=0 -DACE_HAS_EXCEPTIONS -DOTL_STL -DOTL_ORA10G -DOTL_ORA_TIMESTAMP -DOTL_STREAM_NO_PRIVATE_BOOL_OPERATORS -DOTL_STREAM_NO_PRIVATE_UNSIGNED_LONG_OPERATORS -W -Wall -Wpointer-arith -Wno-uninitialized -Woverloaded-virtual -Wcast-align -Wwrite-strings -Wcomments -march=pentiumpro -DCOVERAGE -fprofile-arcs -ftest-coverage -fPIC -Isrc -I/home/lothar/workspace3/tradescapeAPI -I/opt2/ACE_wrappers -I/opt2/ACE_wrappers/TAO -I/opt2/ACE_wrappers/TAO/orbsvcs -I/opt2/boost/include/boost-1_32 -I/opt2/python-2.4/include/python2.4 -I/opt2/log4cplus/include -I/opt2/otl4/include -I/opt2/oracle/product/10.1.0/client_1/rdbms/public -c -o src/utility/.build/posix/coverage/PythonScriptExecutor.os src/utility/PythonScriptExecutor.cpp In file included from /opt2/log4cplus/include/log4cplus/logger.h:20, from src/utility/PythonInterpreterGuard.h:12, from src/utility/PythonScriptExecutor.cpp:7: /opt2/log4cplus/include/log4cplus/config.h:79:1: warning: "HAVE_STAT" redefined In file included from /opt2/python-2.4/include/python2.4/Python.h:55, from /opt2/boost/include/boost-1_32/boost/python/detail/wrap_python.hpp:121, from /opt2/boost/include/boost-1_32/boost/python/detail/prefix.hpp:13, from /opt2/boost/include/boost-1_32/boost/python/args.hpp:8, from /opt2/boost/include/boost-1_32/boost/python.hpp:11, from src/utility/PythonInterpreterGuard.h:10, from src/utility/PythonScriptExecutor.cpp:7: /opt2/python-2.4/include/python2.4/pyport.h:139:1: warning: this is the location of the previous definition /opt2/boost/include/boost-1_32/boost/mpl/aux_/integral_wrapper.hpp:72: error: template argument 2 is invalid /opt2/boost/include/boost-1_32/boost/mpl/aux_/integral_wrapper.hpp:73: error: template argument 2 is invalid /opt2/boost/include/boost-1_32/boost/python/detail/wrapper_base.hpp:24: warning: unused parameter 'x' /opt2/boost/include/boost-1_32/boost/python/detail/wrapper_base.hpp:82: warning: unused parameter 'self' src/utility/PythonScriptExecutor.cpp: In constructor 'xcerla::utility::PythonScriptExecutor::PythonScriptExecutor()': src/utility/PythonScriptExecutor.cpp:41: warning: deprecated conversion from string constant to 'char*'' Lothar -- Lothar Werzinger Dipl.-Ing. Univ. framework & platform architect Xcerla Corporation 275 Tennant Avenue, Suite 202 Morgan Hill, Ca 95037 email: lothar(a)xcerla.com phone: +1-408-776-9018

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