March 2011 - Boost-users - lists.boost.org

[asio] recommended way of handling unix signals ?
by Avi Bahra 22 Mar '11

22 Mar '11

I have been looking at the boost asio 1.45 docs but there is no mention of signal handling ? Is this is a known deficiency of asio, or are there any any recommended ways of handling signals in a asio server ? Best regards, Ta, Avi

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boost::asio close TCP connection cleany
by Marco Piacentini 22 Mar '11

22 Mar '11

Hy..I've seen in the tutorial that client side disconnect is called simply by a break in the read loop. I would like to know which is the step-by-step instruction to close correctly a TCP connection (both server and client side) and where I have to put them. I've seen the close and shutdown functions, but I don't know where call them. Finally...what I can do when an EOF error happens?? thank you..

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RegEx - Exception on faulty RE, or other report of failure.
by Kerry, Richard 22 Mar '11

22 Mar '11

Using Boost Regex for the first time I note that if there is an error in the syntax of the RE given then an exception is raised. Is this the only way of checking the RE syntax ? Or is there a function that I can call which can validate it for me without an exception. I don't see anything in the documentation (I'm using Boost 1.4 as I need to use it with Visual C++ 6). Regards, Richard. Richard Kerry BNCS Engineer Siemens IT Solutions and Services Ltd The Business Technologists Room 457 Drama Building, BBC Television Centre, Wood Lane, London, W12 7RJ T: +44 (0)20 82259063 F: +44 (0)20 8576 8182 M: +44 (0)7921 244993 Email: richard.kerry(a)siemens.com<blocked::mailto:richard.kerry@siemens.com> Website: www.siemens.co.uk/it-solutions<blocked::outbind://47/www.siemens.co.uk/it-solutions> This e-mail contains confidential information and is for the exclusive use of the addressee/s. If you are not the addressee, then any distribution, copying or use of this e-mail is prohibited. If received in error, please advise the sender and delete it immediately. We accept no liability for any loss or damage suffered by any person arising from use of this e-mail. Siemens IT Solutions and Services Limited Registered No: 1203466 England Registered Office: Faraday House, Sir William Siemens Square, Frimley, Camberley, GU16 8QD

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Boost - How does VC know what to link ?
by Kerry, Richard 22 Mar '11

22 Mar '11

Can someone explain (*) how Visual Studio gets to know which lib file to link with ? I see an entry (Auto-Linking under point 6 on the Getting Started page) which says that it does this, but I'd like to know how. I want to be sure that once I've started using Boost in a project then any of my colleagues building the same project will get the libraries pice-up properly. (*) or point me to the code that does it. Is is some sort of compiler directive that controls it ? It's Visual Studio 6 that I'm using, but I expect it's the same for others. Richard Kerry BNCS Engineer Siemens IT Solutions and Services Ltd The Business Technologists Room 457 Drama Building, BBC Television Centre, Wood Lane, London, W12 7RJ T: +44 (0)20 82259063 F: +44 (0)20 8576 8182 M: +44 (0)7921 244993 Email: richard.kerry(a)siemens.com<blocked::mailto:richard.kerry@siemens.com> Website: www.siemens.co.uk/it-solutions<blocked::outbind://47/www.siemens.co.uk/it-solutions> This e-mail contains confidential information and is for the exclusive use of the addressee/s. If you are not the addressee, then any distribution, copying or use of this e-mail is prohibited. If received in error, please advise the sender and delete it immediately. We accept no liability for any loss or damage suffered by any person arising from use of this e-mail. Siemens IT Solutions and Services Limited Registered No: 1203466 England Registered Office: Faraday House, Sir William Siemens Square, Frimley, Camberley, GU16 8QD

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[autolink] for gcc?
by alfC 22 Mar '11

22 Mar '11

Hi, I recently discovered boost/auto_link.hpp which besides the comment in the source file doesn't seem to be documented. The question is, can it be used with gcc c++? if not, is there an alternative? Thank you, Alfredo

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[asio] deadline_timer not waiting properly?
by Dylan Klomparens 22 Mar '11

22 Mar '11

Hello, I tried using the boost deadline_timer in this simple test application, but had some trouble. The goal is for the timer to trigger every 45 milliseconds using the "expires_at()" member function of the deadline_timer. (I need an absolute time, so I'm not considering expires_from_now(). I am also not concerned about drift at the moment). When I run the program, wait() does not wait for 45 ms! Yet, no errors are reported. Am I using the library incorrectly somehow? -- Dylan Sample program: #include <boost/asio.hpp> #include <boost/thread.hpp> #include <boost/bind.hpp> #include <boost/date_time/posix_time/posix_time.hpp> #include <iostream> using namespace std; int main() { boost::asio::io_service Service; boost::shared_ptr<boost::thread> Thread; boost::asio::io_service::work RunForever(Service); Thread = boost::shared_ptr<boost::thread>(new boost::thread(boost::bind(&boost::asio::io_service::run, &Service))); boost::shared_ptr<boost::asio::deadline_timer> Timer(new boost::asio::deadline_timer(Service)); while(1) { boost::posix_time::time_duration Duration; Duration = boost::posix_time::microseconds(45000); boost::posix_time::ptime Start = boost::posix_time::microsec_clock::local_time(); boost::posix_time::ptime Deadline = Start + Duration; boost::system::error_code Error; size_t Result = Timer->expires_at(Deadline, Error); cout << Result << ' ' << Error << ' '; Timer->wait(Error); cout << Error << ' '; boost::posix_time::ptime End = boost::posix_time::microsec_clock::local_time(); (cout << "Duration = " << (End - Start).total_milliseconds() << " milliseconds" << endl).flush(); } return 0; }

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boost binary_iarchive compiler error converting from side_t to streamsize
by Liron Kopinsky 21 Mar '11

21 Mar '11

Hi all, I'm having a problem were, when I #include <boost/archive/binary_iarchive.hpp>, it says that there is an error converting from size_t to std::streamsize. This seems to come from basic_binary_iprimitive.hpp line 181 because std::memcpy takes a size_t but it's passing in a std::streamsize. This seems to just be a warning, but even though I added #pragma warning(disable : 4244) and my compiler still isn't happy and gives this output: http://boost.codepad.org/faSZmjNM We seem to only have this problem when we're building in VS2010, but it works fine in 2005. Any help would be appreciated. Thanks, Liron Kopinsky Image Metrics Software Developer liron.kopinsky(a)image-metrics.com

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Boost Concept Library - fusion and other libraries
by Robert Ramey 21 Mar '11

21 Mar '11

Lately I've been exploring boost/fusion for a project which I have been thinking about for 25 years. I believe that this might be the tool to do what I want. In the course of my experiments with this library and it's associated documentation, I've been interested in understanding the libraries "concepts" (e.g. AssociativeSequence, etc) and the relationship if any to the boost concept library. To try to be more clear, when I see something in the documentation like "AssociativeSequence", I'm sort of hoping/expecting to write into my code something like template<typename S> struct my_type { ... BOOST_CONCEPT_ASSERT(( <AssociativeSequence<S> > )); ... }; But it seems that I can't do this. Why is this? a) Can I indeed write something like this if I include some specific headers that I haven't found? b) Should I be using some other concept checker such as something in MPL c) Am I wrong about thinking that it would be useful to have this? That is, is there some reason why I shouldn't expect to find this? In poking around, I don't find a lot I'm expecting to find. For example, I'm sort of expecting to find: boost::std::concepts { ... concept checking classes for STL } and something similar for all or most of the libraries who make extensive usage of "concepts" in their documentation. When I so grep for files which contain BOOST_CONCEPT (to catch BOOST_CONCEPT_ASSERT, etc.. I get the following: bash-3.2$ pwd /cygdrive/c/BoostRelease/boost bash-3.2$ grep -l BOOST_CONCEPT * */*.hpp concept_archetype.hpp concept_check.hpp concept/assert.hpp concept/requires.hpp concept/usage.hpp concept_check/borland.hpp concept_check/general.hpp concept_check/has_constraints.hpp concept_check/msvc.hpp graph/bron_kerbosch_all_cliques.hpp graph/buffer_concepts.hpp graph/graph_concepts.hpp graph/graphviz.hpp graph/metric_tsp_approx.hpp graph/stoer_wagner_min_cut.hpp graph/tiernan_all_cycles.hpp graph/transitive_reduction.hpp icl/closed_interval.hpp icl/continuous_interval.hpp icl/discrete_interval.hpp icl/interval_base_map.hpp icl/left_open_interval.hpp icl/map.hpp icl/open_interval.hpp icl/right_open_interval.hpp iterator/iterator_concepts.hpp range/concepts.hpp bash-3.2$ which suggests to me that this idea is only implemented in graph, icl, iterator and range libraries. Is there a reason for this, or is that it just hasn't been done. If it's the latter, is there a reason I don't see anyone on the requesting that libraries include concept checking classes. Also, reviewers don't seem to mention the lack of these classes in the code - though they complain about it if it's missing from the documentation. After sort of struggling with the whole concept concept, I'm think I'm coming to appreciate it's utility and maybe it's necessity. But given that no one seems to miss it in the boost libraries, I'm concerned that I'm still not getting it. Robert Ramey

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Re: [Boost-users] [boost::thread] interrupt a future get boost::unknown_exception
by 乔志强 21 Mar '11

21 Mar '11

It is only boost::thread int foo() { this_thread::sleep(seconds(1000)); return 0; } int main(int argc, char** argv) { boost::packaged_task<int> pt(&foo); boost::unique_future<int> fi = pt.get_future(); .......................... > > ------------------------------ > > Message: 2 > Date: Fri, 18 Mar 2011 16:43:54 +0100 > From: Viatcheslav.Sysoltsev(a)h-d-gmbh.de > To: boost-users(a)lists.boost.org > Subject: Re: [Boost-users] [boost::thread] interrupt a future get > boost::unknown_exception > Message-ID: <op.vsjpzgww5q4lf0@pc-sysolts-zdmf> > Content-Type: text/plain; charset=utf-8; format=flowed; delsp=yes > > On Fri, 18 Mar 2011 11:30:11 +0100, ??? <qiaozhiqiang(a)leadcoretech.com> > wrote: > > > [Windows XP, VC++ 10, boost 1.46] > > When interrupt a future, the future.get() throw boost::unknown_exception, > > Not boost::thread_interrupted. > > > > Class boost::thread_interrupted should have a base class for > > current_exception_impl() to catch it ? or use BOOST_THROW_EXCEPTION in > > interruptible_wait) ? > > > > > > /////////////// > > namespace boost > > { > > class thread_interrupted > > {}; > > } > > > > > > exception_ptr current_exception_impl() > > { > > try > > { > > throw; > > } > > catch( > > exception_detail::clone_base & e ) > > { > > return exception_ptr(e.clone()); > > } > > ................ > > catch( > > std::exception & e ) > > { > > return > > exception_detail::current_exception_unknown_std_exception(e); > > } > > catch( > > boost::exception & e ) > > { > > return > > exception_detail::current_exception_unknown_boost_exception(e); > > } > > catch( > > ... ) > > { > > return > > exception_detail::current_exception_unknown_exception(); > > } > > > > > > // unknown_exception////////////////// > > ERROR: Throw in function (unknown) > > Dynamic exception type: class boost::exception_detail::clone_impl<class > > boost::unknown_exception> > > std::exception::what: Unknown exception > > > > > > > > //code ///////////////////// > > #include <boost/thread.hpp> > > #include <boost/date_time/posix_time/posix_time_types.hpp> > > #include <boost/thread/future.hpp> > > using namespace boost::posix_time; > > using namespace boost; > > > > int main(int argc, char** argv) > > { > > boost::packaged_task<int> pt( > > [=]()->int > > { > > this_thread::sleep(seconds(1000)); > > return 0; > > } > > ); > > boost::unique_future<int> fi = pt.get_future(); > > boost::thread task(std::move(pt)); // launch task on a thread > > > > task.interrupt(); > > > > try > > { > > int v = fi.get(); > > } > > catch (boost::exception& exc) > > { > > std::cerr << "ERROR: " << boost::diagnostic_information(exc) << > > std::endl; > > } > > } > > Wow, boost-1.46 and lambdas, you're really working on the edge. Just to be > sure it is a boost problem - can you make a classical function instead > lambda and try with it? The test case seems nearly like one from the > futures example - I really doubt it is a boost problem. > I'd be glad to experiment with it yourself but my latest ubuntu has only > gcc 4.4.5 and the lambdas said to be supported first from 4.5, plus I'd > need to build 1.46 first, which takes quite a time on my nearly-netbook.. > > -- Slava > >

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mpl and set of maps
by Peter Foelsche 21 Mar '11

21 Mar '11

It looks like two maps with the same entries but different ordering are considered different. I'm trying to create a set of maps and I'm inserting two maps. Both maps are identical but the order in which the items were inserted into the map is different. I was thinking that an associative sequence like set is using is_same to compare two elements and I tried to overload is_same -- but this did not work. See code below or attached. #include <boost/mpl/set.hpp> #include <boost/mpl/map.hpp> #include <boost/mpl/bool.hpp> #include <boost/mpl/long.hpp> #include <boost/mpl/for_each.hpp> #include <boost/mpl/insert.hpp> #include <iostream> ? struct print { template<typename T> void operator()(const T &_r) const { //std::cout << typeid(T).name() << "\n"; (*this)(_r, typename boost::mpl::is_sequence<T>::type()); } template<typename T> void operator()(const T &, const boost::mpl::true_ &) const { std::cout << "(\n"; boost::mpl::for_each<T>(print()); std::cout << ")\n"; } template<typename T0, typename T1> void operator()(const boost::mpl::pair<T0, T1> &, const boost::mpl::false_ &) const { std::cout << "pair(" << typeid(T0).name() << ", " << typeid(T1).name() << ")" << "\n"; } template<typename T> void operator()(const T &, const boost::mpl::false_ &) const { std::cout << typeid(T).name() << "\n"; } }; namespace boost { //namespace type_traits //{ //template<typename T0, typename T1> //struct is_same; ? using boost::mpl::map; using boost::mpl::true_; using boost::mpl::insert; ? template<typename T0, typename T1> struct is_same<map<T0, T1>, map<T1, T0> > { typedef boost::mpl::true_ type; }; ? template<typename T0, typename T1, typename T2> struct is_same<map<T0, T1, T2>, map<T2, T1, T0> > { typedef boost::mpl::true_ type; }; ? template<typename T0, typename T1, typename T2> struct is_same<map<T0, T1, T2>, map<T1, T2, T0> > { typedef boost::mpl::true_ type; }; ? template<typename T0, typename T1, typename T2> struct is_same<map<T0, T1, T2>, map<T0, T2, T1> > { typedef boost::mpl::true_ type; }; ? template<typename T0, typename T1, typename T2> struct is_same<map<T0, T1, T2>, map<T1, T0, T2> > { typedef boost::mpl::true_ type; }; //} } int main(int argc, char **argv) { using boost::mpl::long_; using boost::mpl::for_each; using boost::mpl::set; using boost::mpl::map; using boost::mpl::pair; using boost::mpl::insert; typedef long_<0> zero; typedef long_<1> one; typedef long_<2> two; typedef pair< zero, one > zero_2_one; typedef pair< one, one > one_2_one; for_each< insert< insert< set<>, insert< insert< map<>, zero_2_one >::type, one_2_one >::type >::type, insert< insert< map<>, one_2_one >::type, zero_2_one >::type >::type >(print()); return 0; }

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