Mailman 3 February 2003 - Cplusplus-sig

class scope
by Jochen Heckl Feb. 17, 2003

Feb. 17, 2003

Hello everybody, How can I leave a scope while exporting classes. Entering a scope works fine, but I can't return ro global scope. I'm using MSVC .net eith the latest version of boost_python. I have the following code scope InX = class_< X ..... ; // from now on every declaration is in scope X:: - works fine .... // this should return to global scope - but does not scope(); class_< Y .... ; // Y is still defined in scope X::. What am I doing wrong ? // can somebody help please.... Jochen Heckl NovaTrix GmbH Ettishofer Str. 10C 88250 Weingarten EMail: jochen.heckl(a)novatrix.de <mailto:jochen.heckl@novatrix.de> Phone: 0049 (0) 751 50921- 57 Fax: 0049 (0) 751 50921- 31

2 1

Re: MS Visual C++ integrated environment
by horace(seednet) Feb. 16, 2003

Feb. 16, 2003

Nicolas Lelong wrote : > I believe this should be 'BOOST_PYTHON_MODULE(PyTest)' [ no '_' ] if >python really looks after 'initPyTest'. ------------------------------- Yes, Nicolas, you are absolutely right, thanks alot. Finally, I can enojoy the power of Boost.Python, as well as the comfortableness of MS Visual C++ integrated developing environment. Regards Horace

1 0

Wrong python found
by John J Lee Feb. 15, 2003

Feb. 15, 2003

Would be nice if boost python could find the right python executable on systems like mine -- I have 2.2 installed, but python is a link to 2.1, so unless I hack python.jam to set PYTHON = /usr/bin/python2.2 I get link errors on running the tests. A PYTHON_BIN would do the trick, but I think if PYTHON_VERSION is set, /usr/bin/python2.2 should be preferred over /usr/bin/python. John

2 2

MS Visual C++ integrated environment
by horace(seednet) Feb. 14, 2003

Feb. 14, 2003

I have built one small .pyd file using MS Visual C++ integrated environment, my code snippet looks like this : #include <boost/python.hpp> using namespace boost::python; enum choice { red,green,blue}; BOOST_PYTHON_MODULE(_PyTest) { enum_<choice>("choice") .value("red",red) .value("green",green) .value("blue",blue) ; } However the .pyd file won't work : >>> import PyTest Traceback (most recent call last): File "<pyshell#0>", line 1, in ? import PyTest ImportError: dynamic module does not define init function (initPyTest) >>> What had gone wrong ? Do I have to use bjam to build it ? I have one bigger project suffers the same error message. In the begining I thought it was something wrong inside the code, however, obviously it wasn't. Help ! Comfortable developing environment will always be my first choice, so do others, I believe. Horace

2 1

PyPython
by M. Evans Feb. 13, 2003

Feb. 13, 2003

http://codespeak.net/mailman/listinfo/pypy-dev

1 0

Problem with derivation of abstract class
by Pierre Barbier de Reuille Feb. 13, 2003

Feb. 13, 2003

I'm learning how to wrap C++ classes in python. I'm following the (out of date ?) tutorial and I have this non-working example : I have these very simple C++ class and function : struct Base { virtual int f() = 0; }; int call_f(Base &b) {return b.f();} To wrap it, I have to write a wrapper class deriving from the Base class : struct BaseWrap : Base { BaseWrap(PyObject *self_) : self(self_) {} int f () {return call_method<int>(self,"f");} PyObject *self; }; and I have to define the python binding : BOOST_PYTHON_MODULE(base_abs) { class_<Base, BaseWrap , boost::noncopyable>("Base", no_init); def("call_f",call_f); } When I compile it using bjam, everything goes okay. But now, in the python interpreter, I try to derive the class Base like this : >>> from base_abs import * >>> class Derived(Base): ... def f(self): ... return 42 ... At this point, everything's still okay. But, if I want to instanciate an object of classe Derived, I obtain: >>> d = Derived() Traceback (most recent call last): File "<stdin>", line 1, in ? RuntimeError: This class cannot be instantiated from Python The problem being apparently the __init__ method. Because if I redefine this __init__ method with something that does nothing, I can instanciate a Derived object : >>> def constructor(self): ... pass ... >>> Derived.__init__=constructor >>> d=Derived() >>> d.f() 42 But still, if I now want to use the defined class_f function, I have an error : >>> call_f(d) Traceback (most recent call last): File "<stdin>", line 1, in ? TypeError: bad argument type for built-in operation Although, the derivation tree seems to be correct: >>> issubclass(Derived,Base) 1 So, is there any change in boost.python ? What do I have to do for that example to work ? Thanks, -- Pierre Barbier de Reuille INRA - UMR Cirad/Inra/Cnrs/Univ.MontpellierII AMAP Botanique et Bio-informatique de l'Architecture des Plantes TA40/PSII, Boulevard de la Lironde 34398 MONTPELLIER CEDEX 5, France tel : (33) 4 67 61 65 77 fax : (33) 4 67 61 56 68

2 1

Boost cold feet
by Jonathan Brandmeyer Feb. 11, 2003

Feb. 11, 2003

I have an interest in an old Python extension module that was written in C++. The interface is managed by some old stuff that LLNL built in the late 1990's (97?). Since it predates the C++ standard, it is not standard-compliant and I am looking for a modern replacement. I see that you folks have built up what looks like a much better interface to Python, but I have some basic questions to ask. 1. Is the entire Boost system required to be installed on an end-user's machine to use a C++-based extension module that uses python-boost? 2. What is the bare minimum run-time support that a C++ module requires using your extension system, exempting system libraries and python itself? 3. How painful is it to learn Boost's jam-based build system? 4. Can the python->C++ extension library be built and used the old-fashoned way (i.e. make)? 5. Debian doesn't offer either Boost or python_boost in _any_ distribution. Any ideas why? This is a big source of doubt for me, since I use Debian. 6. Any idea about how significantly boost's jam system clashes with the Debian Way? 7. Do I /have/ to use the jam system to build my module for Python? How badly does Boost pin me into using their build system? Basically, I'm worried about getting locked into a rare build system, and I want to restrict my project's dependant codebase to the standard system libraries to the maximum extent possible. Thanks, Jonathan

4 4

Inheritance with B/P
by Bruce Lowery Feb. 11, 2003

Feb. 11, 2003

The short tutorial section on inheritance seems very clear. However, the following doesn't work for me: struct Base {}; struct Derived : Base {} struct SomeOther { void someFunc( Base* o ); } When wrapped (using bases<..> for Derived), the following gives a type error: > d = mod.Derived() > s = mod.SomeOther() > s.someOther( d ) TypeError: bad argument type for built-in operation > In reality, the wrappers "hold" Base and Derived using auto_ptr: class_< Base, auto_ptr<Base> >(...) ...; class_< Derived, auto_ptr<Derived>, bases<Base> >(...) ...; Any ideas? Bruce Lowery __________________________________________________ Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now. http://mailplus.yahoo.com

3 15

overloaded member functions in boost.python
by Anthony Baxter Feb. 6, 2003

Feb. 6, 2003

[I initially sent this to python-list - I completely forgot about c++-sig. Any help would be greatly appreciated...] Does anyone have any examples using Boost::Python that are more complex than the simple ones in the tutorial? I'm trying to wrap a large class library (OpenH323) and I'm constantly banging my head against weird errors that are more or less trial and error to figure out. The only chunks of code I can find are the bits in the "test" directory of the distribution, and they're all a bit... artificial. The specific case I'm trying to solve at the moment is that I have a class (H323Connection) that defines a number of variants of a member function MakeCall: H323Connection * MakeCall( const PString & remoteParty, /// Remote party to call PString & token, /// String to receive token for connection void * userData = NULL /// user data to pass to CreateConnection ); H323Connection * MakeCall( const PString & remoteParty, /// Remote party to call H323Transport * transport, /// Transport to use for call. PString & token, /// String to receive token for connection void * userData = NULL /// user data to pass to CreateConnection ); PString is the class library's own String class - I've already got functions working that accept them, and return them, fine (using converters). It's really not clear to me how I'm supposed to specify which of these methods I want to call. The BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS macro seems to be more about the numbers of arguments, rather than choosing from methods with different argument types. BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS(makecall_overloads, H323EndPoint::MakeCall, 2, 3); ... class_<H323EndPoint>("H323EndPoint") .def("MakeCall", &H323EndPoint::MakeCall, makecall_overloads(args("remoteParty", "token"))) produces h323.cpp:166: no matching function for call to `boost::python::class_<H323EndPoint, boost::python::detail::not_specified, boost::python::detail::not_specified, boost::python::detail::not_specified>::def(const char[9], <unknown type>, makecall_overloads)' I've tried reading the reference documentation, to no avail. Is there another source of information out there that I'm missing? Thanks, Anthony -- Anthony Baxter <anthony(a)interlink.com.au> It's never too late to have a happy childhood.

2 1

RE: Boost.Python v2: Keywords
by Nikolay Mladenov Feb. 5, 2003

Feb. 5, 2003

3 11