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Exposing static members using boost.python
by sashan 06 Sep '02

06 Sep '02

Hi Is the correct way to expose static members by writing a wrapper function for them? For example void wrap_fn() { Class::fn(); } . . . this_module.def(wrap_fn, "fn"); Thanks in advance Sashan

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array.hpp problem with msvc7 and stlport
by li_lirong 06 Sep '02

06 Sep '02

I got many errors with boost\array.hpp after I chaged to use stlport instead of the one from msvc7. one of these errors is: d:\cpplibs\boost\boost\array.hpp(61) : error C2039: '_Ptrit' : is not a member of '_STL' I have tried to config stlport with STLP_NO_OWN_NAMESPACE and _STLP_DONT_RENAME_STD but the errors still exist. Is it a bug in array.hpp or stlport? Regards, Lirong

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ref. to object functions from threads
by Luis De la Parra 06 Sep '02

06 Sep '02

hi all, is there a way to get a reference to the function object used by a boost::thread object?? when you create a new thread and feed it a function object it copies it and then starts a new thread of execution on this object.. well, I would like to send messages to the object in which the thread is running but I don't know how to do it with boos.threads... is there a way to tell boost:thread not to copy the function object but to use it directly?, or to ask the thread object to give a reference to the object? I am now doing a dirty hack which consists of the object putting itself (a pointer) in a static chained list during construction and remove itself in the destructor, this way I can call a static member function which returns this list to get a hold of the object. There is also a static mutex protecting this list to make sure no other objects are created / destructed while one of them is inserting or removing itself from the list. it is working, but I don't think this is a very "clean" approach.. does anyone have any ideas how it could be done better?? thank you. regards, luis.

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n-ary ordered tree template in boost ??
by Marc Cromme 06 Sep '02

06 Sep '02

Dear Boost Members I was wondering if there is an n-ary ordered tree template in boost, something like template <size_t N, class Type, class Alloc = allocator<Type > > class NTree which is a standard container, and a reversible container, ordered by level. That is, first element is root, next series of elements are childs of roots, next series are grandchilds of root , and so on. This way one could parse level by level like a reversible container. There should be the obvious member functions for inserting/deleting child nodes and subtrees. As far as I can see, there is not such a template in boost, but the question is then: 1) can it be emulated using the grah library ?? or 2) is there already an proposal/prototype for such a thing ?? or 3) would it be interesting to include such a thing in boost ?? your's sincierely, Marc Cromme

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[BGL] 2D/3D layout algorithms
by Andrew Cunningham 06 Sep '02

06 Sep '02

Has anyone adapted any 2D and/or 3D graph layout algorithms to work with Boost ( i.e. minimum crossing etc...). Seems an obvious question, but I did not find anything via searching... Andrew

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RE: [Boost-Users] Re: Is it possible to retrieve blank strings with boost::tokenizer?
by Sean Shubin 05 Sep '02

05 Sep '02

That did it. Thanks. -----Original Message----- From: Markus Schöpflin [mailto:markus.schoepflin@ginit-technology.com] Sent: Thursday, September 05, 2002 1:48 AM To: boost-users(a)yahoogroups.com Subject: [Boost-Users] Re: Is it possible to retrieve blank strings with boost::tokenizer? char_separator<char> sep("\t", "", keep_empty_tokens); should do the trick. HTH, Markus

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Newbie boost::mem_fn problem
by Mark Snelling 05 Sep '02

05 Sep '02

Hello, My problem I think is very simple, I just can't seem to find the solution I have an STL list of object pointers and I want to call a member function on each of the pointers in the list usigng the STL for_each algorithm. This would seem easy if the list contained the actual objects rather than pointers to them, but because they are pointers I can't find a way of doing this. class Block { public: void update(int x); }; void main() { list<Block*> blocks; for_each(blocks.begin(), blocks.end(), *****); // Call update on each item in list } what should I replace the ***** with? Any help appreciated! Mark.

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RE: [Boost-Users] Re: msvc-stlport build problems
by Jim.Hyslop 05 Sep '02

05 Sep '02

David Resnick (dresnick(a)mobilespear.com) wrote: > I've fixed the problem, here's my solution in case anyone > else needs it: Hi, David Would you mind taking a moment to add this to the Boost Users Wiki site? Follow this URL: http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl?CommonBuildPr oblems and edit the page to add a brief description of the problem and how you solved it. Thanks! -- Jim

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Is it possible to retrieve blank strings with boost::tokenizer?
by Sean Shubin 05 Sep '02

05 Sep '02

For example, using the code: string line = "\taaa\t\tbbb\t"; typedef tokenizer<char_separator<char> > tok; char_separator<char> sep("\t"); tok tokens(line, sep); for(tok::iterator i = tokens.begin();i!=tokens.end();++i) { cout << "\t\"" << *i << "\"" << endl; } I get this output: "aaa" "bbb" I want to get this output: "" "aaa" "" "bbb" ""

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boost.python overloading to_python
by dkottowk 04 Sep '02

04 Sep '02

hi, please consider the following example class A { public: A() {} A(const A& a) {} }; class A2 : public A { public: A2() : A() {} A2(const A2& a2) : A(a2) {} }; class B { public: const A& getA(); //returns refs to A or A2 }; now, when exposing this in boost, i would always get A's when calling B::getA() from python, which i understand, since AFAIK the copy Ctors are used to instantiate the python object. to overcome this i wrote: PyObject *to_python(const A &a) { if (dynamic_cast<A2*>(&a)) { return to_python::((const A2 &)a);//done by class_builder<A2> } else { //HOW DO I CALL THE IMPL DONE BY class_builder<A> ? return 0; } } which works fine, except that i dont know how to resort to the automatic implementation for PyObject *to_python(const A& a) provided by the class builder for A. any help is greatly appreciated. greetings, daniel

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