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Detecting None in Boost.Python
by ahakim777 31 Jul '03

31 Jul '03

Hi, This is a Boost.Python question. How do I detect that a Python function has passed a 'None' to a wrapped C++ function? Cheers, Ammar

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filesystem::path & wide char strings?
by Cody Batt 30 Jul '03

30 Jul '03

Hello, I want to use the filesystem::path class for a project I'm working on, but I need to support wide character strings in the path names. I might be missing something, but it seems that path only supports std::string. Is this because of a portability issue or what is the rationale for not using something like basic_string<CharType>? Are there any plans to provide support for wide character strings in the future? Thanks, Cody Batt

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howto map c++ namespaces using boost::python?
by cavok＠filibusta.crema.unimi.it 30 Jul '03

30 Jul '03

hi all, i'm a newbie user of Boost. i need some suggestions to expose c++ namespaces in python. in python i use classes as namespaces, but using class_ construct to build python classes seems to not be applicable to c++ namesapces. moreover, i have a global c++ object which i'd like to map onto python. it is not that clear to me how i can achieve this result. thanks domenico -----[ Domenico Andreoli, aka cavok --[ http://filibusta.crema.unimi.it/~cavok/gpgkey.asc ---[ 3A0F 2F80 F79C 678A 8936 4FEE 0677 9033 A20E BC50

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Boost Bind on MSVC 7.1
by Dale Peakall 30 Jul '03

30 Jul '03

The following example is a very simple, and contrived, example that demonstrates the problem I'm seeing. This fails to compile with 'term does not evaluate to a function taking 1 arguments'. Is this a problem with bind on MSVC 7.1, or have I just forgotton how to use it/what it can do. - Dale. #include <iostream> #include <string> #include <boost/bind.hpp> int my_function(std::string const& value) { return static_cast<int>(value.length()); } int main() { std::string my_string("hello world!"); std::cout << boost::bind<int>(_1, my_string)(my_function); }

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boost.python exception
by newwz2003 29 Jul '03

29 Jul '03

Can I raise exception in C++ module can catch it in python ? or where can I get detailed doc about boost.python? Thank you

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Deferred Function Forwarding
by vivek_arora 29 Jul '03

29 Jul '03

I am looking for pointers on how to use boost to implement a set of template classes/helper functions which can be used for deferred function/method call forwarding. Here's an example of illustrating what I wish to accomplish. I can live with restictions on the function argument types. //Define a template type which can capture arguments of any (or most) functions. I believe boost tuple could suit my requirements. //Define a template helper function save_args which constructs a arguments tuple based on the signature of the function passed as the first argument. e.g . R f(T1, T2, T3); boost:tuple<R, T1, T2, T3> args = save_args(f, t1, t2, t3); //Don't want to explicitly specify types like save_args<R,T1,T2,T3> (t1,t2,t3) //Define another template helper function call_with_args which given another function "g" with a signature conforming with "f" and the argument tuple invokes "g" e.g. R g(T1, T2, T3) //This should call g(args.get<0>, args.get<1>, args.get<2>) call_with_args(g, args); Could someone provide ideas, pointers/sample code for implementing save_args, call_with_args helper template functions. Thanks -Vivek Arora

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Feature Suggestion
by everwicked 29 Jul '03

29 Jul '03

Hello guys, I have just been introduced to the library by some people at Efnet's #c++ and I have to say there is quite a lot of useful work in there. I hope boost makes it into the standard. It's about time to get a feature rich std library. Want I wanted to ask you is to provide a few more functions in library interval. I was comparing boost with blitz++ as the parts I need at the moment are mainly of scientific nature. Anyways, I found boost more to my likeness because it has other features I might want to use later, because it supports more compilers and lastly because it's API is better organised in my opinion. The functions that I find that are missing from library 'interval' are the ones listed here: http://www.oonumerics.org/blitz/manual/blitz03.html#l77 Is there any chance you could implement them in boost? I wouldn't ask but I think that they are not a lot of work. Thanks in advance. Kind regards, George

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boost_date_time: ftime ==>gettimeofday for microsec_clock?
by dick.bridges＠tais.com 28 Jul '03

28 Jul '03

I need a microsec_clock on Windows XP. My first impulse is to define gettimeofday() implemented using ftime(). Should this work ok or am I missing something obvious? TIA

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Newbie - stack overflow in connected components
by Frank H 28 Jul '03

28 Jul '03

Hello: Environment: Windows 2K, MSVC 6 SP5, Boost 1.30.0 I'm new to BGL ( 2 days experience ) and am trying to use the connected components graph. My implementation seems to be OK for my small test case ( 10 verticies) but when I run my "real data" through it ( 15000 verticies) I get a stack overflow error. I note that there is a patch in the sourceforge CVS for the dfs algoritm which implements a non-recursive solution from dgregor that I understand will avoid the stack overflow. I naively downloaded the "depth_first_search.hpp" V1.35 from the CVS and of course it doesn't compile. The question: "How can I apply the patch to fix the stack problem( ie how to determine what and where are the other files I need or do I download the entire current version ( ie tag MAIN)?" Thanks for any help Frank

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RE: [Boost-Users] Newbie missing a header for boost_date_time?
by dick.bridges＠tais.com 28 Jul '03

28 Jul '03

<history> <snip/> > ...which refers to lexical_cast.hpp > > template<typename Target, typename Source> > class lexical_stream > { > bool operator<<(const Source &input) > { > here ===> return stream << input; <==== here > } > } <snip/> I'm starting to think this may be related to the 1_30_0 lexical cast problem. Can you upgrade lexical_cast.hpp from cvs? You can download it from here: http://cvs.sourceforge.net/cgi- bin/viewcvs.cgi/boost/boost/boost/lexical_cast.hpp Jeff </history> I downloaded the head this (Monday) morning and replaced the 1_30_0 version. Compile error disappeared. (Sanity check: copied the 'old' version back and compile error re-appears.) Thanks for the help. That was driving me nuts.

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