July 2011 - Boost-users - lists.preview.boost.org

More Boostcon videos available
by Marshall Clow 07 Jul '11

07 Jul '11

Monday: Micheal Wong - C++0x Progress and status http://blip.tv/boostcon/c-0x-progress-and-status-5349952 Ruediger Berlich - Distributed parametric optimization with the Geneva library http://blip.tv/boostcon/distributed-parametric-optimization-with-the-geneva… Tuesday: Joel Falcou - Automatic Hybrid MPI+OpenMP Code Generation http://blip.tv/boostcon/automatic-hybrid-mpi-openmp-code-generation-5349961 Sebastian Schaetz - Mastering the Cell Broadband Engine architecture through a Boost based parallel communication library http://blip.tv/boostcon/mastering-the-cell-broadband-engine-architecture-th… Beman Daves -- The proposed Boost B-tree library http://blip.tv/boostcon/the-proposed-boost-b-tree-library-5349968 Boris Kolpackov - Parsing C++ with GCC plugi http://blip.tv/boostcon/parsing-c-with-gcc-plugins-5349971 More next week.... -- Marshall Marshall Clow Idio Software <mailto:mclow.lists@gmail.com> A.D. 1517: Martin Luther nails his 95 Theses to the church door and is promptly moderated down to (-1, Flamebait). -- Yu Suzuki

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xml_oarchive to a iostream
by Sillence, Martin (GE Oil & Gas) 07 Jul '11

07 Jul '11

Hi, Am I missing something or is there no way to serialise to a network stream? Using the blocking method for sending and receiving I have a boost::asio::ip::tcp::iostream and need a boost::archive::xml_oarchive to serialise to/from unfortunately I can't work out how to create a xml_oarchive from the network iostream. I see from the examples most people are serialising to a buffer and then sending that but it would be much neater to be able to use a stream directly. Am I missing something or is this a gap? Thanks, M

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Threads and virtual functions
by Geoffrey 07 Jul '11

07 Jul '11

Hello, here is a simplified code I wrote: class A{ public: A(); ~A(); void Run(); void ThreadA(); virtual void HandleSomething(); }; void A::HandleSomething() { } void A::ThreadA() { if(condition) { HandleSomething(); } } void A::Run() { boost::thread thread(&A::ThreadA,this); } This is my base class. As you can see the thread calls the virtual function when the condition becomes true. I use the virtual function in my derived class so everytime the condition becomes true the function HandleSomething() should do something. So far, so good but when I try to change some variables in the derived class the program crashes without any warning or error message. I use the latest Ubuntu version with GCC 4.5.3 and boost 1.46.1.

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[chrono] Intel Composer XE 2011 unable to compile chrono library
by Edward Rankin 06 Jul '11

06 Jul '11

Hi, The purpose of this email is to get some insight on the problem we faced when trying to compile chrono from the 1.47 Beta 1 package. I have tried both the latest released compiler (2011 Update 4) and the current SP1 beta. There is no issue with VS 2010 SP1's compiler. It was first surfaced here: http://comments.gmane.org/gmane.comp.lib.boost.user/68421. The error received can be seen below: < snip > chrono.cpp .\boost/chrono/duration.hpp(94): error: expected an expression && (boost::is_convertible<Rep2, ^ .\boost/chrono/duration.hpp(124): error: expected an expression && (boost::is_convertible<Rep, ^ < snip > After some discussion with Vicente and some testing by me, it turns out that Intel was not happy with the first operand of the && operator in the following snippet of code: template <class Duration, class Rep2, bool = ( (boost::is_convertible<typename Duration::rep, typename common_type<typename Duration::rep, Rep2>::type>::value) && (boost::is_convertible<Rep2, typename common_type<typename Duration::rep, Rep2>::type>::value) ) > struct duration_divide_imp { }; If we place an additional parenthesis around that first operand like this: template <class Duration, class Rep2, bool = ( ( (boost::is_convertible<typename Duration::rep, typename common_type<typename Duration::rep, Rep2>::type>::value) ) && (boost::is_convertible<Rep2, typename common_type<typename Duration::rep, Rep2>::type>::value) ) > struct duration_divide_imp { }; It will happily compile. It is rather bizarre that this is necessary, which leads Vicente and I to believe that there is a bug in the Intel Compiler. What do you guys think? I have also posted to the Intel forums, the thread can be seen here: http://software.intel.com/en-us/forums/showthread.php?t=84061 Regards, Edward

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[units] combined systems and prefixes and output
by alfC 06 Jul '11

06 Jul '11

Hi, After some effort I managed to add a new system to boost units (namely "atomic"). The system works so far until I start using si prefixes in combination and printing int main(){ clog << 4.*atomic::hbar << endl; // output: 4 hbar clog << 4.*(si::femto*si::second) << endl; // output: 4 fs clog << 4.*(atomic::hbar/si::second) << endl; // output: 4 s^-1 hbar auto a = atomic::hbar/(si::femto*si::second); // ok clog << a << endl; // output: P(s^-1 hbar) auto b = 4.*atomic::hbar/(si::femto*si::second); // ok clog << b << endl; // error!!!! why? return 0; } As you see all lines work as expected except for the last line. Is there a workaround? do I need to define prefixes specific for the other system of units? The error message boils down to: usr/include/boost/units/detail/linear_algebra.hpp:197:48: error: no type named ‘item’ in ‘struct boost::units::list<boost::units::list<boost::units::static_rational<0l, 1l>, boost::units::list<boost::units::static_rational<1l>, boost::units::dimensionless_type> >, boost::units::dimensionless_type>::next’ also I defined hbar as struct reduced_planck_constant_base_unit : base_unit< reduced_planck_constant_base_unit, action_dimension, 3 >{ static string name(){return ("reduced Planck constant");} static string symbol() {return ("hbar");} }; static const action hbar;

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accumulators doc typo?
by Olaf Peter 06 Jul '11

06 Jul '11

Hi, at http://www.boost.org/doc/libs/1_46_1/doc/html/accumulators/user_s_guide.html in the example of section 'Droppable Accumulators' one can read // This will display "6 2 3" std::cout << sum(acc) << ' ' << count(acc) << ' ' << mean(acc); The text below says 'Note that at the point at which mean is dropped, sum is 3, count is 2, and therefore mean is 1.5'. After calculating my result is also 1.5 - the comment in the example isn't correct, isn't it? Probably the typo is in the upcoming release 1.47 too. Regards, Olaf

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[bimap] initializing from range of pair<T&, U&> elements
by Nathan Ridge 06 Jul '11

06 Jul '11

Hello, I am trying to initialize a bimap<T, U> with a vector<pair<T&, U&>> (the "vector" part isn't important, any range with elements of type pair<T&, U&> has the same effect), but I'm getting a rather monstrous compiler error. The same initialization works for std::map<T, U>. Here is the code: #include <boost/bimap.hpp> #include <boost/range/begin.hpp> #include <boost/range/end.hpp> #include <vector> #include <map> #include <utility> int main() { int i1, i2; float f1, f2; std::vector<std::pair<int&, float&>> myvec{{i1, f1}, {i2, f2}}; std::map<int, float> m(boost::begin(myvec), boost::end(myvec)); // WORKS boost::bimap<int, float> b(boost::begin(myvec), boost::end(myvec)); // FAILS } The compiler errors are shown below. It seems to me this should work. As with std::map, the pair-of-iterators constructor should call something like insert(const value_type&) for each element of the range, where value_type is something like pair<const T, U> which should be constructible from pair<T&, U&>, the element type of the range. Why is this not working? Thanks, Nate. P.S. Here are the errors: In file included from B:\Dev\Libraries\boost/boost/bimap/detail/bimap_core.hpp:34:0, from B:\Dev\Libraries\boost/boost/bimap/bimap.hpp:61, from B:\Dev\Libraries\boost/boost/bimap.hpp:13, from test.cpp:1: B:\Dev\Libraries\boost/boost/multi_index_container.hpp: In constructor 'boost::multi_index::multi_index_container<Value, IndexSpecifierList, Allocator>::multi_index_container(InputIterator, InputIterator, boost::multi_index::multi_index_container<Value, IndexSpecifierList, Allocator>::ctor_args_list&, boost::multi_index::multi_index_container<Value, IndexSpecifierList, Allocator>::allocator_type&) [with InputIterator = __gnu_cxx::__normal_iterator<std::pair<int&, float&>*, std::vector<std::pair<int&, float&> > >, Value = boost::bimaps::relation::mutant_relation<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, mpl_::na, true>, IndexSpecifierList = boost::bimaps::detail::bimap_core<int, float, mpl_::na, mpl_::na, mpl_::na>::core_indices, Allocator = std::allocator<boost::bimaps::relation::mutant_relation<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, mpl_::na, true> >, boost::multi_index::multi_index_container<Value, IndexSpecifierList, Allocator>::ctor_args_list = boost::tuples::cons<boost::tuples::tuple<boost::multi_index::member<boost::bimaps::relation::detail::relation_storage<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, true>, float, &boost::bimaps::relation::detail::relation_storage<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, true>::right>, std::less<float>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>, boost::tuples::cons<boost::tuples::tuple<boost::multi_index::member<boost::bimaps::relation::detail::relation_storage<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, true>, int, &boost::bimaps::relation::detail::relation_storage<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, true>::left>, std::less<int>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>, boost::tuples::null_type> >, boost::multi_index::multi_index_container<Value, IndexSpecifierList, Allocator>::allocator_type = std::allocator<boost::bimaps::relation::mutant_relation<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, mpl_::na, true> >]': B:\Dev\Libraries\boost/boost/bimap/bimap.hpp:252:8: instantiated from 'boost::bimaps::bimap<KeyTypeA, KeyTypeB, AP1, AP2, AP3>::bimap(InputIterator, InputIterator, boost::bimaps::bimap<KeyTypeA, KeyTypeB, AP1, AP2, AP3>::allocator_type&) [with InputIterator = __gnu_cxx::__normal_iterator<std::pair<int&, float&>*, std::vector<std::pair<int&, float&> > >, KeyTypeA = int, KeyTypeB = float, AP1 = mpl_::na, AP2 = mpl_::na, AP3 = mpl_::na, boost::bimaps::bimap<KeyTypeA, KeyTypeB, AP1, AP2, AP3>::allocator_type = std::allocator<boost::bimaps::relation::mutant_relation<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, mpl_::na, true> >]' test.cpp:15:70: instantiated from here B:\Dev\Libraries\boost/boost/multi_index_container.hpp:235:9: error: no matching function for call to 'boost::multi_index::multi_index_container<boost::bimaps::relation::mutant_relation<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, mpl_::na, true>, boost::bimaps::detail::bimap_core<int, float, mpl_::na, mpl_::na, mpl_::na>::core_indices, std::allocator<boost::bimaps::relation::mutant_relation<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, mpl_::na, true> > >::insert_(std::pair<int&, float&>&, boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::index_node_base<boost::bimaps::relation::mutant_relation<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, mpl_::na, true>, std::allocator<boost::bimaps::relation::mutant_relation<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, mpl_::na, true> > > > >*)' B:\Dev\Libraries\boost/boost/multi_index_container.hpp:484:30: note: candidates are: std::pair<typename boost::multi_index::detail::multi_index_base_type<Value, IndexSpecifierList, Allocator>::type::node_type*, bool> boost::multi_index::multi_index_container<Value, IndexSpecifierList, Allocator>::insert_(const Value&) [with Value = boost::bimaps::relation::mutant_relation<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, mpl_::na, true>, IndexSpecifierList = boost::bimaps::detail::bimap_core<int, float, mpl_::na, mpl_::na, mpl_::na>::core_indices, Allocator = std::allocator<boost::bimaps::relation::mutant_relation<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, mpl_::na, true> >, typename boost::multi_index::detail::multi_index_base_type<Value, IndexSpecifierList, Allocator>::type::node_type = boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::index_node_base<boost::bimaps::relation::mutant_relation<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, mpl_::na, true>, std::allocator<boost::bimaps::relation::mutant_relation<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, mpl_::na, true> > > > >] B:\Dev\Libraries\boost/boost/multi_index_container.hpp:505:30: note: std::pair<typename boost::multi_index::detail::multi_index_base_type<Value, IndexSpecifierList, Allocator>::type::node_type*, bool> boost::multi_index::multi_index_container<Value, IndexSpecifierList, Allocator>::insert_(const Value&, boost::multi_index::multi_index_container<Value, IndexSpecifierList, Allocator>::node_type*) [with Value = boost::bimaps::relation::mutant_relation<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, mpl_::na, true>, IndexSpecifierList = boost::bimaps::detail::bimap_core<int, float, mpl_::na, mpl_::na, mpl_::na>::core_indices, Allocator = std::allocator<boost::bimaps::relation::mutant_relation<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, mpl_::na, true> >, typename boost::multi_index::detail::multi_index_base_type<Value, IndexSpecifierList, Allocator>::type::node_type = boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::index_node_base<boost::bimaps::relation::mutant_relation<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, mpl_::na, true>, std::allocator<boost::bimaps::relation::mutant_relation<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, mpl_::na, true> > > > >, boost::multi_index::multi_index_container<Value, IndexSpecifierList, Allocator>::node_type = boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::index_node_base<boost::bimaps::relation::mutant_relation<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, mpl_::na, true>, std::allocator<boost::bimaps::relation::mutant_relation<boost::bimaps::tags::tagged<const int, boost::bimaps::relation::member_at::left>, boost::bimaps::tags::tagged<const float, boost::bimaps::relation::member_at::right>, mpl_::na, true> > > > >] mingw32-make: *** [test.exe] Error 1

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[asio] [thread] Code review for correct use of boost sockets and threads
by Konrad Reiche 06 Jul '11

06 Jul '11

Hello everyone, I am using the boost library now for a couple of weeks. Unfortunately I've run into some problems with my C++ code and I would like to make sure that these problems are not caused due to incorrect use of boost. So basically I've written a small class which is suppossed to take messages and send them asynchronously. If there are more messages than can be processed, they queue up. The code is mainly based on the tutorial code provided on the boost website: http://www.boost.org/doc/libs/1_39_0/doc/html/boost_asio/tutorial/tutdaytim… I have 2 questions: 1. The constructor launches the threads, from this point on I want to be able to queue up messages, which are processed afer that by using the function MessageService::write. Is there any possible problem which could occur due to buffer or thread issues? Because sometimes the messages are not processed until the end and when they are processed they are corrupted. 2. Sometimes the messages are not processed when the application would quit. I have to make sure, that the messages are sent at least at the end. Sometimes there are 10.000+ messages queued up, so this might take a bit time. For this I've wrote MessageService::await(). It seems really bogus to me. I am checking the pending messages left for the following reason: When the host I am connecting to does not listen on the port I am connecting to, I don't receive an error by the functions I am using. So the messages are queued up and nothing happens. I don't know why. Have I forgot any checking whether the connection could be established? In the hope my question is not too generic, I would be really grateful for any advice. I am sorry I could not provide any specific errors, but this is due to the reason all the problems evolve on the client side by receiving corrupted messages. - Konrad /* * MessageService.cpp * * Created on: 04.06.2011 * Author: Konrad Johannes Reiche */ #include "MessageService.h" using namespace google::protobuf::io; using boost::asio::ip::tcp; MessageService::MessageService(std::string ip, std::string port) : work(io_service), resolver(io_service), socket(io_service) { messageQueue = new std::deque<AgentMessage>; tcp::resolver::query query(ip, port); endpoint_iterator = resolver.resolve(query); tcp::endpoint endpoint = *endpoint_iterator; socket.async_connect(endpoint, boost::bind(&MessageService::handle_connect, this, boost::asio::placeholders::error, ++endpoint_iterator)); boost::thread t(boost::bind(&boost::asio::io_service::run, &io_service)); } void MessageService::await() { while (!messageQueue->empty()) { signal(SIGINT, exit); int messagesLeft = messageQueue->size(); sleep(3); std::cout << "Pending Profiler Agents Messages: " << messageQueue->size() << std::endl; if (messagesLeft == messageQueue->size()) { std::cout << "Connection Error" << std::endl; break; } } } void MessageService::write(AgentMessage agentMessage, long systemTime, int JVM_ID) { agentMessage.set_timestamp(Agent::Helper::getCurrentClockCycle()); agentMessage.set_jvm_id(JVM_ID); agentMessage.set_systemtime(systemTime); io_service.post(boost::bind(&MessageService::do_write, this, agentMessage)); } void MessageService::do_close() { socket.close(); } void MessageService::transmitMessage(AgentMessage agentMessage) { boost::asio::streambuf b; std::ostream os(&b); ZeroCopyOutputStream *raw_output = new OstreamOutputStream(&os); CodedOutputStream *coded_output = new CodedOutputStream(raw_output); coded_output->WriteVarint32(agentMessage.ByteSize()); agentMessage.SerializeToCodedStream(coded_output); delete coded_output; delete raw_output; boost::system::error_code ignored_error; boost::asio::async_write(socket, b.data(), boost::bind( &MessageService::handle_write, this, boost::asio::placeholders::error)); } void MessageService::do_write(AgentMessage agentMessage) { bool write_in_progress = !messageQueue->empty(); messageQueue->push_back(agentMessage); if (!write_in_progress) { transmitMessage(agentMessage); } } void MessageService::handle_write(const boost::system::error_code &error) { if (!error) { messageQueue->pop_front(); if (!messageQueue->empty()) { transmitMessage(messageQueue->front()); } } else { std::cout << error << std::endl; do_close(); } } void MessageService::handle_connect(const boost::system::error_code &error, tcp::resolver::iterator endpoint_iterator) { // can be used to receive commands from the Java profiler interface } MessageService::~MessageService() { // TODO Auto-generated destructor stub }

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Re: [Boost-users] weird Google page when I try to search boost.org
by Richard L. Aurbach 05 Jul '11

05 Jul '11

I get it too. Simple query using both Safari and FireFox on Mac OS X. And on these browsers at this time (7/5/2011 3pm CDT) adding site:www.boost.org to the query doesn't help either... Cheers, Rick Aurbach, Ph.D. President and Chief Engineer Aurbach & Associates, Inc. 8233 Tulane Avenue, Suite B St. Louis, MO 63132 www: http://www.aurbach.com/ eMail: support(a)aurbach.com [business] rick(a)aurbach.com [personal] Fax: 314/678-0869 Phone: 800/774-7239 314/726-1321 "Elitism is the slur directed at merit by mediocrity." - Sydney J. Harris, journalist (1917-1986) "Life is easy to chronicle, but bewildering to practice." - E.M. Forster (1879-1970) "Cowardice asks the question, 'Is it safe?' Expediency asks the question, 'Is it politic?' Vanity asks the question, 'Is it popular?' But, conscience asks the question, 'Is it right?' And there comes a time when one must take a position that is neither safe, nor politic, nor popular but one must take it because one's conscience tells one that it is right." -Martin Luther King, Jr. (1929-1968) "The saddest aspect of life right now is that science gathers knowledge faster than society gathers wisdom." -Isaac Asimov (1920-1992) "If in the last few years you haven't discarded a major opinion or acquired a new one, check your pulse. You may be dead." - Gelett Burgess (1866-1951) "You can judge your age by the amount of pain you feel when you come in contact with a new idea." - John Nuveen (1896-1968) “The scientific theory I like best is that the rings of Saturn are composed entirely of lost airline luggage.” - Mark Russell (1932- )

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Specifying of the filesystem3::path for custom strings using
by Iurii Gordiienko 05 Jul '11

05 Jul '11

Hi I tried to specify the boost::filesystem3::path to use my custom string (icu based) but in result I have error during my code compiling and I can't solve it... I have this issue under Linux, because under Windows ICU has equal with boost char-representation (wchar_t), but under Linux these values are different. The attach has error-screenshot and part of code which has conversion specification etc... Please, help Thanks -- Iurii Gordiienko

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