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[asio] global timer cancellation?
by Brian and Victoria 19 Mar '09

19 Mar '09

Hi, I've got various objects that make use of the asio deadline timer to schedule events. The problem is that there isn't a central repository of timer references that I can walk to cancel them when shutting down asio. I'd like to be able to just tell asio to cancel any pending work and have the thread(s) return. Is this possible? I came across the io_service::work class but haven't yet found an example of how it works. Thanks, Brian

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dynamic_bitset count
by Andreas Klein 19 Mar '09

19 Mar '09

Hello. Sorry for multiple posts. Hopplfully I got I now right. ----------------------------------------------------- Dear boost developers, I checked the implementation of boost::dynamic_bitset::count and find that it uses a table look up. This is not optimal. First on 64-bit machines divide-and-conquer algorithms are faster than table look up and save even memory. Second if the bitset contains several words, there are for both 32 and 64 bit machines population count algorithms that are faster than the simple loop over all words used by boost. Together with Y. Edel I developed a new version,which saves 60% against the simple algorithm. We put the code online (http://cage.ugent.be/~klein/popc.html) A disadvantage of our implementation is that we relay on aggressive optimization (-O3) of the compiler. If you are searching a compromise between speed and code complexity. The first iteration of the Harley-Seal-method (25% faster than the simple loop) would be a candidate. You find this and other population count algorithms on our homepage, too. If there is interest I can add one of the advance algorithms in boost. Best wishes Andreas Klein

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[shared_ptr] calling shared_from_this from constructor
by Пюрецкий 18 Mar '09

18 Mar '09

Hi, A have just get latest version from SVN. And now my code does not work. I found problem in a changed version of shared_ptr and shared_from_this (revision 51485). Now calling shared_from_this in constructor throw's boost::bad_weak_ptr exception. -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.

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boost::is_less::result_type
by Arno Schödl 18 Mar '09

18 Mar '09

Shouldn't boost::is_less et. al. define typedef bool result_type; for interoperability with boost::bind? Arno -- Dr. Arno Schoedl · aschoedl(a)think-cell.com Technical Director think-cell Software GmbH · Invalidenstr. 34 · 10115 Berlin, Germany http://www.think-cell.com · phone +49-30-666473-10 · toll-free (US) +1-800-891-8091 Directors: Dr. Markus Hannebauer, Dr. Arno Schoedl · Amtsgericht Charlottenburg, HRB 85229

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Google SOC Mentors?
by John Maddock 18 Mar '09

18 Mar '09

Would folks willing to mentor students for this years GSOC please step forward and make themselves known? We need both people to assist in assessing the student applications, and experienced Boosters to mentor the students themselves. We really need to get some new blood into this if our SOC participation is to continue - we can't rely on the "usual suspects" taking this on year after year - in short, "Your Boost Needs You!". Regards, John Maddock.

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Re: [boost] [lexical_cast] Strange behaviour
by raindog＠macrohmasheen.com 18 Mar '09

18 Mar '09

What exactly do you think -1 is as an unsigned int? ------Original Message------ From: Robert Jones Sender: boost-bounces(a)lists.boost.org To: boost(a)lists.boost.org ReplyTo: boost(a)lists.boost.org Sent: Mar 18, 2009 9:03 AM Subject: [boost] [lexical_cast] Strange behaviour Trying again 'cos I mucked up the code last time! This code #include <iostream> #include <boost/lexical_cast.hpp> int main() { using namespace std; try { unsigned int u=boost::lexical_cast<unsigned int>("-1"); cout << u << '\n'; } catch(const std::exception&) { cout << "Exception" << '\n'; } } produces 4294967295 on MSVC7 & 8 rather than an exception. Is it supposed to do this? Rob. _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost Sent from my Verizon Wireless BlackBerry

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Re: [boost] Range_Ex and Multi-Index: conflicting mpl::begin and boost::begin
by JOAQUIN M. LOPEZ MUÑOZ 18 Mar '09

18 Mar '09

________________________________________ De: boost-bounces(a)lists.boost.org [boost-bounces(a)lists.boost.org] En nombre de Joaquin M Lopez Munoz [joaquin(a)tid.es] Enviado el: miércoles, 18 de marzo de 2009 19:49 Para: boost(a)lists.boost.org Asunto: Re: [boost] Range_Ex and Multi-Index: conflicting mpl::begin and boost::begin > Sandeep Gupta <gupta.sandeep <at> gmail.com> writes: > > > Thanks for looking into this Vicente. I am not directly adding > > boost::mpl to the namespace. Please find attached the code. Below is > > the full error. > > > [...] > > /home/sandeep/Computing/boost_1_38_0/boost/range_ex/./detail/ > > adl_begin_end.hpp:27: > > error: in call to ‘begin’ [...] Adding to my previous post, I found the following in the Boost users list: http://lists.boost.org/boost-users/2006/01/16513.php Seems related, doesn't it? Alas the thread concludes with no satisfactory answer. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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Range_Ex and Multi-Index: conflicting mpl::begin and boost::begin
by Sandeep Gupta 18 Mar '09

18 Mar '09

Hi, I am under-impression that for_each construct of range_ex for all container concepts. However when I tried with multi-index it gave conflicting errors. Attached below is the code and corresponding errors. code: typedef multi_index_container< std::pair<value_type,int>, indexed_by< ordered_unique<member<pair<value_type,int>, value_type, &pair<value_type, int>::first> >, ordered_unique<member<pair<value_type,int>, int, &pair<value_type, int>::second> > > > mic; mic serialStore; for_each(serialStore, std::cout<<boost::lambda::_1<<' '); error: /home/sandeep/Computing/boost_1_38_0/boost/mpl/begin_end_fwd.hpp:22: error: ‘template<class Sequence> struct boost::mpl::begin’ is not a function, /home/sandeep/Computing/boost_1_38_0/boost/range/begin.hpp:96: error: conflict with ‘template<class T> typename boost::range_iterator::type boost::begin(T&)’ /home/sandeep/Computing/boost_1_38_0/boost/range_ex/./detail/adl_begin_end.hpp:27: error: in call to ‘begin’ /home/sandeep/Computing/boost_1_38_0/boost/mpl/begin_end_fwd.hpp:23: error: ‘template<class Sequence> struct boost::mpl::end’ is not a function, /home/sandeep/Computing/boost_1_38_0/boost/range/end.hpp:92: error: conflict with ‘template<class T> typename boost::range_iterator::type boost::end(T&)’ /home/sandeep/Computing/boost_1_38_0/boost/range_ex/./detail/adl_begin_end.hpp:35: error: in call to ‘end’ I apologies in advance if this is due to trivial omission. Thanks -sandeep

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[soc2009] Boost is in summer of code 2009: attention mentors
by troy d. straszheim 18 Mar '09

18 Mar '09

All, We've just been accepted as an organization in Google's Summer of Code 2009. Per this user's guide: http://socghop.appspot.com/document/show/program/google/gsoc2009/userguide those who have volunteered to mentor need to create a site-wide profile, and apply to mentor for Boost, then I'll click you in. Student applications start March 23rd. Until then: - Plan your application. - Brainstorm about project ideas on the mailing lists and IRC. - Familiarize yourself with existing work in the areas you are interested in by reading the mailing list archives and playing with existing Boost libraries. - Make proposals and get feedback. More as I get it. Thanks to Google and their Melange dev team. Looking forward to a good GSOC 2009. -t

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Boost::Format add-on
by Joel Falcou 18 Mar '09

18 Mar '09

Who is in charge of Format maintenance ? I would like to propose a simple patch to add an accessor to the number of arguments expected by the formating : int args() const { return num_args_; } Regards

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[array] change proposal for the c_array() function
by herve martin 18 Mar '09

18 Mar '09

Hi, I'm new in this mailing list .My interest are embedded software and code reuse. I would submit a simple change request in the boost::array library. The boost::c_array() function is expected to cast a boost::array<T,N> into a C-array but actually the returned type is a T* which is not exactly a reference on a C-array. to keep track of the static size and make sizeof( myarray.c_array() ) returning the real size of the C-array, I suggest to change: T* c_array() { return elems; } into T (&c_array())[N] { return *(T(*)[N]) elems; } by the way, I have developed a function helper array_cast<> whose purpose is to: * make a bit more friendly the syntax when casting to a C-array * check consistency between size of the input type and size of the target C-array for example, { long titi; char (&test)[4] = utils::array_cast<char>( titi ); test[0] = 0; } assuming that long is 32 bit long and char is 8 bit long, 'test[0]' is now a reference on the 1st byte of 'titi'. Moreover declaring test as a char(&)[5] would have failed in compiling since size of both types are not suitable (but the function provides some other way to force cast when sizes are not compatible) do you think that there could be any interest to include this function in boost library ? thanks, herve

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Why my subexpression doesn't work in Regex
by Qihong Wang 18 Mar '09

18 Mar '09

Hello, I'm a new boost and regex user. I tried a c++ regex sample as follows regex pattern("banan\\(an\\)*a"); string str = "bananana"; if(regex_match(str, pattern)) cout<<"---- pattern matched ----"<<endl; else cout<<"---- pattern unmatched ----"<<endl; To my surprise, the it printed out pattern unmatched. If I change str to "banan(an)a", the result is pattern matched. Feels like boost.Regex doesn't treat ( ) as subexpression. Any idea? Thanks, Qihong Wang

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[lexical_cast] Strange behaviour
by Robert Jones 18 Mar '09

18 Mar '09

Trying again 'cos I mucked up the code last time! This code #include <iostream> #include <boost/lexical_cast.hpp> int main() { using namespace std; try { unsigned int u=boost::lexical_cast<unsigned int>("-1"); cout << u << '\n'; } catch(const std::exception&) { cout << "Exception" << '\n'; } } produces 4294967295 on MSVC7 & 8 rather than an exception. Is it supposed to do this? Rob.

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[utility] new auto_buffer class --- RFC
by Thorsten Ottosen 18 Mar '09

18 Mar '09

Dear all, For a long time I have been missing this utility in my own work, and in boost related stuff too. I think there are a number of libraries in boost that can benefit from this utility. Libs like boost.format can be quite a bit more effective. So can logging libraries. etc. Basically boost::auto_buffer<T,N> is a C++ version of variable lenght array (from C99). It's based on Matthew Wilson's stlsoft::auto_buffer, which can be found described in his book "Imperfect C++". I have changed a few things though: // - no swap() and resize() provided // - works with allocators from Boost.Interprocess // - do not store T[N] on the stack, as this is bad when the // type has a non-trivial default constructor. // - handless non-pod types in an exception-safe manner // - has a fixed capacity, but a non-fixed size // - provides a non-growing (thus inlineable) push_back() Comments are most welcome. best regards -Thorsten

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reference to ‘_1’ is ambiguous
by Sandeep Gupta 18 Mar '09

18 Mar '09

Hi, This problem has appeared before on the list but in a different context. The following code std::vector<int> myvec; for_each(myvec, std::cout<<_1<<' '); gives the error: Serializer.h:78: error: reference to ‘_1’ is ambiguous /home/sandeep/Computing/boost_1_38_0/boost/lambda/core.hpp:69: error: candidates are: const boost::lambda::placeholder1_type& boost::lambda::<unnamed>::_1 /home/sandeep/Computing/boost_1_38_0/boost/bind/placeholders.hpp:54: error: boost::arg<1> <unnamed>::_1 Serializer.h:78: error: reference to ‘_1’ is ambiguous I believe boost/bind is getting included indirectly via some other library. I have tried several modification but none seem to work as I was quite reluctant to post a third mail on the list. Thanks, sandep

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pointer to member function of multi_index
by Sandeep Gupta 18 Mar '09

18 Mar '09

Hi, I am sure this is due to some trivial mistake; the statement to create a pointer member function insert of multi_index container fails in the following code: typedef multi_index_container< std::pair<int,int>, indexed_by< ordered_unique<member<pair<int,int>, int, &pair<int, int>::first> > > > mic; std::pair<mic_index::iterator, bool> (mic_index::*fn)(pair<int,int>) = &mic_index::insert; //compile error The error is due to mismatch in signature as given in the error: std::pair<boost::multi_index::detail::bidir_node_iterator<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::index_node_base<std::pair<int, int>, ... std::pair<boost::multi_index::detail::bidir_node_iterator<boost::multi_index::detail::ordered_index_node<typename SuperMeta::type::node_type> >, bool>... If need be I can post full error message. Appreciate any suggestions. Thanks sandeep

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correct usage of bind (pls ignore last email)
by Sandeep Gupta 17 Mar '09

17 Mar '09

Hi, The code below tries to chain function ft1 (argument is a pair) with function buildPair (returns a pair). template<typename X, typename Y> std::pair<X, Y> buildPair(X x, Y y) { std::pair<X,Y> apair(x,y); return apair; } int main() { typedef boost::function<void (std::pair<int,int>)> FuncType1_t; std::vector<std::pair<int,int> > myvec; FuncType1_t ft1 = bind(&std::vector<std::pair<int,int> > ::push_back, &myvec, _1); typedef boost::function<void(std::pair<int,int>)> FuncType2_t; FuncType2_t ft2 = bind(ft1, bind(buildPair<int,int>,_1,_2)); //compile fails return 0; } This fails. The problem however vanished if I replace the declaration "FuncType3 ft2..." with bind(ft1, bind(buildPair<int,int>,_1,_2))(3,5); So my question is what is correct type of bind(ft1, bind(buildPair<int,int>,_1,_2)); Thanks sandeep

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correct usage of bind
by Sandeep Gupta 17 Mar '09

17 Mar '09

Hi, Both the statements below bind function buildPair. While the first works the other fails. What could be a possible fix. Thanks in advance. //---- Function to be used by bind ------------------------- template<typename X, typename Y> std::pair<X, Y> buildPair(X x, Y y) { std::pair<X,Y> apair(x,y); return apair; } (std::cout<<buildPair(_1,_2).first<<' ')(1,2); ///--compiles fine--------- (bind(buildPair,_1,_2))(3,5); ///-fails------------ Thanks sandeep

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[Review] Polynomial library review begins today
by John Maddock 17 Mar '09

17 Mar '09

The review of Pawel Kieliszczyk's Polynomial library begins today and ends on Thurs 19th March. Download of the zip file from the vault is here: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=polyno… Otherwise the library is present in the sandbox here: https://svn.boost.org/svn/boost/sandbox/SOC/2008/polynomial/ And the docs can be read online here: https://svn.boost.org/svn/boost/sandbox/SOC/2008/polynomial/libs/docs/index… The polynomial library contains a single class - polynomial<FieldType> - used for the manipulation of polynomials, along with a selection of algorithms which operate upon them. The library is an extension/rewrite of the existing "implementation detail" polynomial class in Boost.Math, and was written as part of last years Google Summer of Code under the mentorship of Fernando Cacciola. What to include in Review Comments ~~~~~~~~~~~~~~~~~~~~~~~~~ Your comments may be brief or lengthy, but basically the Review Manager needs your evaluation of the library. If you identify problems along the way, please note if they are minor, serious, or showstoppers. The goal of a Boost library review is to improve the library through constructive criticism, and at the end a decision must be made: is the library good enough at this point to accept into Boost? If not, we hope to have provided enough constructive criticism for it to be improved and accepted at a later time. The Serialization library is a good example of how constructive criticism resulted in revisions resulting in an excellent library that was accepted in its second review. Here are some questions you might want to answer in your review: * What is your evaluation of the design? * What is your evaluation of the implementation? * What is your evaluation of the documentation? * What is your evaluation of the potential usefulness of the library? * Did you try to use the library? With what compiler? Did you have any problems? * How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? * Are you knowledgeable about the problem domain? And finally, every review should answer this question: * Do you think the library should be accepted as a Boost library? Be sure to say this explicitly so that your other comments don't obscure your overall opinion. Many reviews include questions for library authors. Authors are interested in defending their library against your criticisms; otherwise they would not have brought their library up for review. If you don't get a response to your question quickly, be patient; if it takes too long or you don't get an answer you feel is sufficient, ask again or try to rephrase the question. Do remember that English is not the native language for many Boosters, and that can cause misunderstandings. E-mail is a poor communication medium, and even if messages rarely get lost in transmission, they often get drowned in the deluge of other messages. Don't assume that an unanswered message means you're being ignored. Given constructively, criticism will be taken better and have more positive effects, and you'll get the answers you want. John Maddock. Review Manager for Polynomial Library.

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Re: [boost] [C++-sig] [Python] GSoC and Python 3.0 Support
by Stefan Seefeld 17 Mar '09

17 Mar '09

Niall Douglas wrote: > > I would say that any GSoC project should choose *one* of the above > rather than try combining them. Better to do one thing well and in > stages than many things at once (unless you have loads of spare > time!). > I agree. (I wouldn't mind seeing projects for all of the above, but they definitely shouldn't be combined into one.) >>> Thanks! Seems there's a lot of interesting. So would anyone willing to >>> mentor this? >>> >> Sadly, I suspect that finding a mentor will be difficult (perhaps even more >> difficult than the actual project). Off the top of my head, the following >> folks come to mind: >> - Dave Abrahams >> - Stefan Seefeld >> - Ralf Grosse-Kunstleve >> - Roman Yakovenko >> You might try contacting them off list or on c++-sig (cc'ed on this email). >> I'm willing to participate, in particular, if other folks such as David are part of such a team, too. (While I believe I understand enough of both C++ and Python, lots of boost.python is still very obscure, so having David being part would greatly help. May be we could take the opportunity and collectively work on the (internal) boost.python docs, too. David, I notice you already indicated support. Could we team up for this ? (I will be out on vacation for about two weeks during the summer. Other than that I should be available throughout the summer.) Thanks, Stefan -- ...ich hab' noch einen Koffer in Berlin...

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[fusion] C++0x support?
by Ein Held 17 Mar '09

17 Mar '09

Hello is there any chance for c++0x support (rvalue forwarding for the containers' constructors and operator=s' in particular) for fusion in 1.39? If noone is up to adding support for this to fusion, my collegues and me would love to implement it. Thank you

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Re: [boost] [Review] Polynomial library review begins today
by Chris Card 17 Mar '09

17 Mar '09

On Tue, 10 Mar 2009 12:23:07 -0000, John Maddock <john(a)johnmaddock.co.uk> wrote: > The review of Pawel Kieliszczyk's Polynomial library begins today and > ends on Thurs 19th March. I just saw this and I have a few comments on the interface to the Polynomial class. 1. the name FieldType is mathematically misleading since the instantiating type is very likely not to be a field (e.g. int or a multiple precision integer type). 2. the Polynomial class provides a fairly minimilist set of supported functions. This may well be deliberate (if so, apologies), but I would like to see a richer interface including such things as - content (gcd of coefficients, where that makes sense) - polynomial discriminant - resultant of 2 polynomials - evaluation of homogeneous polynomial ( f(x) = sum c_i x^i, f(a,b) = sum c_i a^i b^(d-i) ) - evaluation at a polynomial (f(g(x))) - Pseudo-division of polynomials - finding roots over C - finding roots over F_p - factorisation over Z - factorisation over F_p Chris

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convert_to: generic conversion between unrelated types
by vicente.botet 16 Mar '09

16 Mar '09

Hi, I need to convert to two unrelated types as chrono::duration and posix_time::time_duration. I have defined a generic function conver_to which use the constructor or conversion operator is the exists. Otherwise the user needs to specialize partially or completly) this function with the unrelated types. This function could be specialized with string and use Boost.StringConvert. In case there is an interest I have attached the files. Best, Vicente

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ASIO certificate help.
by Mohammed Rasmy 16 Mar '09

16 Mar '09

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Boost.Chrono where we are?
by vicente.botet 16 Mar '09

16 Mar '09

Hi, In November 2008, Beman said: "The Chrono library in the sandbox is now more-or-less feature complete." This library is esential to conform some boost libraries implementing standard libraries as Boost.Thread and Boost.Future as much as possible to the standard. It will be used also on the Boost.ThreasPool library and I would like also to use it on my AsynchronousExecutors library. Can we expect to have Boost.Chrono for review soon? Thanks, Vicente

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