Mailman 3 March 2005 - Cplusplus-sig

Re: [C++-sig] 'numpy' test broken?
by Ralf W. Grosse-Kunstleve March 23, 2005

March 23, 2005

> Hello, > using fresh CVS state, I get failure of the 'numpy' test. I run: > > bjam -sPYTHON_ROOT=/usr -sPYTHON_VERSION=2.3 numpy > > and get error. The interesting part of the test output is: I just checked in a workaround (numpy.py in test directory): # Unfortunately the doctest module works differently in Python versions # 2.2, 2.3, and 2.4. Newer versions evaluate all docstrings, even that # of objects with names starting with an underscore. To portably disable # tests based on the availability of Numeric and Numpy, the corresponding # test functions are simply deleted below if necessary. It is not a perfect fix since newer versions of Python's doctest module examine functions that we do not want to have examined, leading to spurious output, but that's all I have time for and the nasty long error messages are gone at least. Cheers, Ralf __________________________________ Celebrate Yahoo!'s 10th Birthday! Yahoo! Netrospective: 100 Moments of the Web http://birthday.yahoo.com/netrospective/

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hello.pyd - where did it go?
by Jesper Olsen March 23, 2005

March 23, 2005

Hi, I just installed boost 1.32 on linux - I want to use Boost.Python. The installation seemed to go ok. After that I tried the hello world example http://www.boost.org/libs/python/doc/tutorial/doc/html/python/hello.html % cd boost_1_32_0/libs/python/example/tutorial % bjam -sTOOLS=gcc -a This seems to work also - a hello.so is created and copied to boost_1_32_0/bin/boost/libs/python/example/tutorial/hello.so but where did hello.pyd go? The above hello.html page says it's supposed to be "somewhere in libs\python\example\tutorial\bin" But it's not there. I have not used bjam prior to boost so I'm a little confused - is it possible to see what the commandline eqivalents of what bjam is actually doing? Is boost usable without bjam? Cheers Jesper

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Making copy of function derived from C++ pure virtual function
by Paul F. Kunz March 23, 2005

March 23, 2005

I have a function written in Python derived from C++. Now I want to clone this function in C++. What should I do in the copy constructor of the function wrapper? I have... FunctionWrap:: FunctionWrap ( const FunctionWrap & wrap ) : FunctionBase ( wrap ), m_self ( wrap.m_self ) { // what should be here to create a new PyObject that is copy of old one? } FunctionBase * FunctionWrap:: clone () const { return new FunctionWrap ( *this ); }

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Exposing BOOST_STRONG_TYPEDEF types.
by kalin March 23, 2005

March 23, 2005

Hi all, I have some types that I have created with BOOST_STRONG_TYPEDEF. I want to manipulate these types from Python, but given that they are not built-in data types, Boost.Python cannot implicitly handle them. So what I want to do is, given BOOST_STRONG_TYPEDEF(size_t, ID) for example, expose this as an 'int'. I suppose you would want to do something like: class_<ID, bases<size_t> >("ID"); It seems you can derive from a built-in data type in Python, I'm not sure what this actually does to the class though. (not a python expert :) ) Does anyone know if there is a 'proper' way to do this with Boost.Python? kalin

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Re: [C++-sig] Re: Embedded Python plus module loading
by Yao Heling March 23, 2005

March 23, 2005

I've never used bjam but the following link may be of help. http://www.python.org/moin/boost.python/BuildingExtensions you can try scons as well, which I found to be easier to use. Regards, Joseph H. Yao On Mon, Mar 21, 2005 at 12:35:33PM -0500, Daniel Holth wrote: > My problem means boost.build doesn't know how to properly link my > embedded Python program. I can add that same line "import sha" to > /libs/python/test/embedding.cpp, build it with 'bjam embedding', and the > test fails to run properly. > > According to the ld manual page I need to use --export-dynamic to expose > symbols coming from static parts of my binary (like the static libpython > boost.build likes to link to) to dynamic libraries like imported python > modules. Or I can just dynamically link libpython > > I haven't sufficiently decoded boost.build to figure out how to change > the library search path to prefer the dynamically loaded Python library > xor add the linker option --export-dynamic, I would prefer to just > dynamically link libpython and it would be nice to keep boost's handy > Python version finder. > > Thanks for any help, > > Daniel Holth > _______________________________________________ > C++-sig mailing list > C++-sig(a)python.org > http://mail.python.org/mailman/listinfo/c++-sig > __________________________________ Do you Yahoo!? Yahoo! Small Business - Try our new resources site! http://smallbusiness.yahoo.com/resources/

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cross-module RTTI issues
by Dan Haffey March 21, 2005

March 21, 2005

Hello, I'm not sure if this is even the right place to post this question, but I'm having some trouble with inheritance across shared library boundaries. I've read the CrossExtensionModuleDependencies Wiki node, and I assume that my problem stems from std::type_info comparison problems, so my question is basically: how do I go about making sure my RTTI info is all coming from the same place? I'm specifically referring to this snippet from the Wiki: "The best way to achieve that is to link both extension modules to a common shared library using the global model, and put the RTTI information there." I'm not sure how exactly I get all the relevant RTTI information into that third library. Just incase I'm completely off-course with my diagnosis of the problem, here's an example of what I'm talking about (this breaks in Linux with gcc 3.3.4): --- A.hpp --- struct A { A() {} virtual int foo() = 0; }; struct Factory { Factory() {} virtual A* make() = 0; }; --- A.cpp --- #include "A.hpp" --- B.hpp --- #include "A.hpp" struct B : public A { B() {} virtual int foo(); }; struct DerivedFactory : public Factory { DerivedFactory() {} virtual A* make(); }; --- B.cpp --- #include "B.hpp" int B::foo() { return 42; } A* DerivedFactory::make() { return new B; } --- A.pyste --- A = Class('A', 'A.hpp') Factory = Class('Factory', 'A.hpp') set_policy(Factory.make, return_value_policy(reference_existing_object)) --- B.pyste --- B = Class('B', 'B.hpp') DerivedFactory = Class('DerivedFactory', 'B.hpp') set_policy(DerivedFactory.make, return_value_policy(reference_existing_object)) And in Python: >>> import A, B >>> x = B.DerivedFactory().make() >>> x.foo() Traceback (most recent call last): File "<stdin>", line 1, in ? Boost.Python.ArgumentError: Python argument types in B.foo(B) did not match C++ signature: foo((anonymous namespace)::B_Wrapper {lvalue}) foo(B {lvalue}) >>> x = B.B() >>> x.foo() 42 >>> Is there a way around this behavior, or is there just no hope for this pattern of shared library usage? Any help would be greatly appreciated, -- Dan Haffey

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Problems with dynamic casts
by Aaron Bentley March 21, 2005

March 21, 2005

Hi, I'm having a problem with dynamic casting on an object constructed using Python. It seems as though the type of an owned object is being lost. I have a test as follows: assert (dynamic_cast<element::Comments *>(loc.getElement(elists[0])) !=NULL); When I invoke it from the constructor of the owning object (the object that owns elists), the test passes. But when I construct the owning object and then invoke the test through Python, it fails. I'm using gcc 3.0.4 from Debian stable. This looks ugly to me. So far the only explanation I've been able to come up with is memory corruption. Aaron -- Aaron Bentley Director of Technology Panometrics, Inc.

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Embedded Python plus module loading
by Daniel Holth March 21, 2005

March 21, 2005

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Okay, I've put a minimal example together. http://dingoskidneys.com/~dholth/minimal-embedding-failure.zip It is the embedding example from boost, with an "import sha" statement added inside it. sha depends on some dynamically loaded code. When I try to run it, it says: ImportError: /usr/lib/python2.3/lib-dynload/sha.so: undefined symbol: Py_FindMethod My Jamfile: project-root ; # Include definitions needed for Python modules SEARCH on python.jam = $(BOOST_BUILD_PATH) ; import python ; # The boost-jam embedding example exe embedding ~ : # sources ~ embedding.cpp ~ : # requirements ~ <threading>multi ~ <find-library>boost_python ~ $(PYTHON_PROPERTIES) ~ <library-path>$(PYTHON_LIB_PATH) ~ <find-library>$(PYTHON_EMBEDDED_LIBRARY) ~ ; I'm not sure where I'm going wrong and I'd appreciate some advice. Embedded Python is more useful when you can load dso's. Thanks, Daniel Holth -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFCPfdLVh4W2pVfoMsRAtsdAKC/d+5VZRWW5O1N1TgEKnVKnlZsFgCdEzTI D6y1iipDrSYmFAl36ykgtoE= =NcnH -----END PGP SIGNATURE-----

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Re: [C++-sig] Re: Embedded Python plus module loading
by Yao Heling March 21, 2005

March 21, 2005

if my memory serves me right, I had a similar problem once. One has to include Python.h or Boost.python headers before other headers are included. or change the linking order of shared libs. Hope that helps. Joseph H. Yao On Mon, Mar 21, 2005 at 04:27:34AM -0500, David Abrahams wrote: > Daniel Holth <dholth(a)fastmail.fm> writes: > > > Okay, I've put a minimal example together. > > > > http://dingoskidneys.com/~dholth/minimal-embedding-failure.zip > > > > It is the embedding example from boost, with an "import sha" statement > > added inside it. sha depends on some dynamically loaded code. When I try > > to run it, it says: > > > > ImportError: /usr/lib/python2.3/lib-dynload/sha.so: undefined symbol: > > Py_FindMethod > > You should post this question on comp.lang.python; it's really not a > Boost-related problem. I'm sure someone there knows how to deal with > it. > > -- > Dave Abrahams > Boost Consulting > www.boost-consulting.com > > _______________________________________________ > C++-sig mailing list > C++-sig(a)python.org > http://mail.python.org/mailman/listinfo/c++-sig > __________________________________ Do you Yahoo!? Yahoo! Mail - Helps protect you from nasty viruses. http://promotions.yahoo.com/new_mail

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Boost.Python with MSVC < v7.1
by Clay Culver March 20, 2005

March 20, 2005

This list seems to have fallen out of date: http://boost.org/libs/python/doc/v2/platforms.html I am working on a GUI widget which uses embedded python. Under windows, the GUI system supports MSVC 6.0, 7.0, and 7.1. If I use Boost.Python will this restrict my widget to being MSVC 7.1 only? I have heard that the current Boost.Python only really works under 7.1, but I don't see anything about it in the documentation. Thanks. Clay

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