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Serialization of an instance of a Derived Template Class
by Pritam Gharat 01 Nov '19

01 Nov '19

Hi, I am using Boost to serialize pointers of a base class which points to instances of a derived template class. I am using boost 1.7.0 and running it on Ubuntu 16.04. The source code of the example is available at https://github.com/PritamMG/Boost-Serialization-Example My example has a base class Bar_A (definition available in include/Abstract.hpp) which has a virtual function toStr(). It has two derived classes Bar_B and Bar_C. Bar_B is a template class. I have registered the derived classes in sc/Test.cpp. Class ObjectNew (include/Object.hpp) has a member pointer of type Bar_A which points to instances of classes Bar_B and Bar_C. I get an error as "unregistered class". I am not sure for which class do I get this error message. There is also an issue of non-default. If Bar_B does not have a default constructor, save_construct_data and load_construct_data are over-ridden and there I run into an error "too many template-parameter-lists". How do I define these functions? Thanks, Pritam

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Re: [Boost-users] [boost] Interest in a Unicode library for Boost?
by Zach Laine 30 Oct '19

30 Oct '19

On Wed, Oct 30, 2019 at 9:47 AM Peter Koch Larsen < peter.koch.larsen(a)gmail.com> wrote: > I saw that talk (on video) and was quite impressed but never got to > try your library out. > Would be happy to use a library like this! Can you tell me how it > relates to the proposed std? > There is no relationship yet. Boost.Text is an experiment meant to gather feedback, which will in turn drive the standardization effort. I believe all large libraries should have Boost-equivalent visibility in the C++ community before being standardized. That being said, some of my fellow SG-16 members (that's the committee's Unicode Study Group) have started proposing some actual APIs for standardization. The first of these is the most low-level: transcoding (see http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1629r0.html ). JeanHeyd's approach is more ambitious than mine -- I really only care about Unicode. His proposal covers conversions among all possible encodings, including an API that lets users add implementations for the encodings they care about that are not covered by the standard. There are no other in-flight Unicode API proposals that I'm aware of. Zach

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Boost.Numeric.Interval: Please specify rounding control mechanism Inbox x UVI x
by Bastien Commelongue 29 Oct '19

29 Oct '19

Hello, I am building an app for IOS (ARM) and I had this issue while compiling: *Boost.Numeric.Interval: Please specify rounding control mechanism.* C99 version should be used in this case but __USE_ISOC99 is not defined. Modifying the condition with this code (using __cplusplus) fixed the issue: *boost/numeric/interval/hw_rounding.hpp(36)* *#if defined(BOOST_NUMERIC_INTERVAL_NO_HARDWARE) && (defined(__USE_ISOC99) || defined(__MSL__) || (defined __cplusplus && __cplusplus >= 201103L))# include <boost/numeric/interval/detail/c99_rounding_control.hpp>#endif* Let me know if I missed something or if you plan to integrate this modification in a next version. Cheers, Bastien Commelongue -- [image: UVI] <http://www.uvi.net/> Bastien Commelongue | Software Development A. 159 rue Amelot - 75011 Paris - France T. 0033671833955 • M. b.commelongue(a)uvi.net <email(a)uvi.net> [image: Facebook] <http://www.facebook.com/UVI.Official> [image: Twitter] <http://twitter.com/UVIofficial> [image: Youtube] <http://www.youtube.com/user/UVIofficial> [image: SoundCloud] <http://soundcloud.com/uvi-official> [image: Instagram] <http://instagram.com/weareuvi/>

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[BGL] minimum cut separating two given vertices on undirected graph
by Ziye Tang 18 Oct '19

18 Oct '19

Hi all, This is my first time posting, and I've read the posting guideline. I might still make some mistakes in the posting style. In particular, I am not sure how to insert code snippet into email. Please let me know when I do make such mistakes. I need to find a min-cut separating a given pair of vertices on an undirected graph. Conceptually this is how I would solve it: first I bidirect the graph, treat one vertex as the source and the other as the sink. Then run any max flow algorithm from source to sink. When the algorithm finishes, in the residual graph, identify connected component which contains a given vertex. This gives the min-cut. In order to implement it, I use push_relabel_max_flow. According to the doc I need to augment each edge with a reverse edge. Since I bi-directed the graph already, this would give rise to a multi-graph where each edge, say (i,j) has two copies, with the first copy treated as the `true' edge and the second copy as the reverse edge of arc (j,i). Then I set capacity and residual capacity map accordingly. But now I am getting a segmentation error when calling push_relabel_max_flow. Could you help me understand what is going on? I've attached my code snippet below. Here g is my graph, n is the number of vertices, xval is a 2 by 2 positive matrix where each corresponding entry is the capacity of the edge. for (int i=0; i<n; i++) for (int j=i+1; j<n; j++) { graph_traits<Graph>::out_edge_iterator e_start, e_end, e_start2, e_end2;; boost::tie(e_start, e_end) = boost::edge_range(i,j,g); // check if an edge exists if (e_start == e_end) continue; boost::tie(e_start2, e_end2) = boost::edge_range(j,i,g); // set reverse edge, set its capacity to be zero g[*e_start].rev = *(--e_end2); g[*e_start2].rev = *(--e_end); g[*e_start].capacity = xval[i][j]; g[*e_start].res_capacity = xval[i][j]; g[*e_start2].capacity = xval[i][j]; g[*e_start2].res_capacity = xval[i][j]; // now end points to the second parallel edge g[*e_end].capacity = 0; g[*e_end].res_capacity = 0; g[*e_end2].capacity = 0; g[*e_end2].res_capacity = 0; //g[e].rev = boost::edge(j,i,g).first; std::cout << "(" << i << ", " << j << "): " << g[*e_start].capacity << ", " << g[*e_start2].capacity << endl; } Thanks in advance!

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Re: [Boost-users] Help needed with boost::process::child and mysql cli
by Label 17 Oct '19

17 Oct '19

Hello, > Date: Tue, 15 Oct 2019 07:28:54 +0000 > From: name name <jerry-dev(a)outlook.com> > To: "boost-users(a)lists.boost.org" <boost-users(a)lists.boost.org> > Subject: [Boost-users] Help needed with boost::process::child and > mysql cli > Message-ID: > <MN2PR01MB5710C3F35D092D2FDF0B376DF0930(a)MN2PR01MB5710.prod.exchangelabs.com> > > > Content-Type: text/plain; charset="windows-1252" > > Hi, > > Im use boost::process::child to create a mysql cli child process to > import sql file. > Normally im use this command: > /usr/bin/mysql mysql -h127.0.0.1 -utestuser --password='!@#QWE123qwe' > -P3306 --default-character-set=utf8mb4 --max-allowed-packet=1GB < > /root/create_db.sql > It?s worked well in bash. > > But when use boost::process::child, std_err report ERROR 1045 (28000): > Access denied for user 'testuser'@'localhost' (using password: YES). > Is there any bugs in my code? [...] I have no experience with boost::process, only one idea: Maybe the apostrophs around the password are normally eaten by the Linux shell, and you have to leave them out when building your arguments? // connection info args.push_back("-h127.0.0.1"); args.push_back("-utestuser"); args.push_back("--password=!@#QWE123qwe"); // <= args.push_back("-P3306"); Freundliche Grüße * Best regards * Met vriendelijke groeten * Meilleures salutations Holger Gerth _________________________________________________________________________________ EB-Soft Gesellschaft fuer elektronische Beschriftungs-Software mbH Neckargartacher Str. 114, 74080 Heilbronn, Germany Tel: +49 (0)7131 / 9466-0 Email: info(a)ebsoft.de Fax: +49 (0)7131 / 1099-0 Homepage: www.ebsoft.de Amtsgericht-Registergericht-Stuttgart HRB 102882 Geschaeftsfuehrer: Michael Ehring, Helmut Sigler _________________________________________________________________________________

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Help needed with boost::process::child and mysql cli
by name name 15 Oct '19

15 Oct '19

Hi, Im use boost::process::child to create a mysql cli child process to import sql file. Normally im use this command: /usr/bin/mysql mysql -h127.0.0.1 -utestuser --password='!@#QWE123qwe' -P3306 --default-character-set=utf8mb4 --max-allowed-packet=1GB < /root/create_db.sql It’s worked well in bash. But when use boost::process::child, std_err report ERROR 1045 (28000): Access denied for user 'testuser'@'localhost' (using password: YES). Is there any bugs in my code? Os: ubuntu 18.04 LTS Boost: 1.71.0 MySql:5.7.27 Create_db.sql: DROP DATABASE IF EXISTS test_db; CREATE DATABASE test_db; Thanks [code] #include <iostream> #include <boost/algorithm/string/join.hpp> #include <boost/iostreams/copy.hpp> #include <boost/asio/io_context.hpp> #include <boost/process.hpp> using namespace boost::process; using namespace boost::iostreams; using namespace boost::asio; std::string SearchExecutableInPath(std::string const& filename) { try { return search_path(filename).generic_string(); } catch (...) { return ""; } } int RunProcess( std::string const& executable, std::vector<std::string> const& args, std::string input_file_path ) { io_context ioCtx; auto work = make_work_guard(ioCtx); std::thread ioThread([&ioCtx] { ioCtx.run(); }); std::future<std::string> dataOut, dataErr; child c; if (!input_file_path.empty()) { c = child( boost::filesystem::absolute(executable), boost::process::args(args), std_out > dataOut, std_err > dataErr, std_in < boost::filesystem::absolute(input_file_path), ioCtx ); } else { c = child( boost::filesystem::absolute(executable), boost::process::args(args), std_out > dataOut, std_err > dataErr, std_in.close(), ioCtx ); } c.wait(); int result = c.exit_code(); std::string output = dataOut.get(); std::string error = dataErr.get(); if (!output.empty()) { std::cout << output << std::endl; } if (!error.empty()) { std::cout << error << std::endl; } work.reset(); ioThread.join(); return result; } int main() { // /usr/bin/mysql mysql -h127.0.0.1 -utestuser --password='!@#QWE123qwe' -P3306 --default-character-set=utf8mb4 --max-allowed-packet=1GB < /root/create_db.sql std::vector<std::string> args; args.reserve(8); // mysql cli args.push_back("mysql"); // connection info args.push_back("-h127.0.0.1"); args.push_back("-utestuser"); args.push_back("--password='!@#QWE123qwe'"); args.push_back("-P3306"); // encoding args.push_back("--default-character-set=utf8mb4"); // maybe large sql file args.push_back("--max-allowed-packet=1GB"); int const ret = RunProcess( SearchExecutableInPath("mysql"), args, "/root/create_db.sql"); std::cout << "ret code: " << ret << std::endl; return 0; } [/code]

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bg::cs::geographic and nearest query
by vexakul 14 Oct '19

14 Oct '19

Hi all! I need to store geographic points in rtree and be able to answer nearest query. Can someone provide an example similar to this <https://www.boost.org/doc/libs/1_65_1/libs/geometry/doc/html/geometry/spati…> but with point type bg::model::point<float, 2, bg::cs::geographic<bg::degree>>? Is that supported? For me it fails to compile. -- Kind regards, Sergey. -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Users-f2553780.html

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[gil][docs] Image Processing docs structure based on "Principles of Digital Image Processing" book
by Mateusz Loskot 13 Oct '19

13 Oct '19

Hi, (Copying to boost and boost-users lists) If you are passionate about C++ and image processing and interested in writing documentation about it, here is a good first issue for you if you'd like to start contributing to Boost.GIL. During the course of GSoC 2019 we have received first batch of IP features, there is not great deal of content yet, so shouldn't be overwhelming to get started. It's rather a clean slate under your control. Don't be shy! :-) Regards, Mateusz Loskot ---------- Forwarded message --------- From: Mateusz Loskot <mateusz(a)loskot.net> Date: Sun, 13 Oct 2019 at 20:08 Subject: [GH #396] Image Processing docs structure based on "Principles of Digital Image Processing" book To: <boost-gil(a)lists.boost.org> Hi, Following our successful GSoC 2019, I have started discussion on proposal of improved and future-proof structure of the "Image Processing" chapters of GIL documentation. Here are details: https://github.com/boostorg/gil/issues/396 Please, have a look and share your feedback. If there is anyone experienced in writing docs, a technical write, who is looking for ways to contribute to Boost and Boost.GIL, this is a very good first issue to pick :-) Best regards, -- Mateusz Loskot, http://mateusz.loskot.net -- Mateusz Loskot, http://mateusz.loskot.net

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Attributes of sequence and list operator in boost.spirit qi?
by kila 12 Oct '19

12 Oct '19

I also open the same question on stackoverflow. For better formatting of code, please refer to https://stackoverflow.com/questions/58353782/attributes-of-sequence-and-lis… <https://stackoverflow.com/questions/58353782/attributes-of-sequence-and-lis…> I want to parse something like "{xxxx} {xxxx}" which is separated by eol into a *vector<vector<wchar_t>> *: ({xxxx},{xxxx}) so that "{" and "}" stays with internal characters together. Note there are only two elements on the outer vector. My code is: #define BOOST_SPIRIT_UNICODE #include <iostream> #include<boost/spirit/include/qi.hpp> #include<string> #include<vector> using namespace std; namespace sw=boost::spirit::standard_wide; namespace qi= boost::spirit::qi; using boost::spirit::standard_wide::char_; int main() { wstring s = L"{\"id\":23,\"text\":\"sf\nsf\"}\n{\"id\":23,\"text\":\"sfsf\"}"; qi::rule<wstring::iterator, vector<vector<wchar_t>>(), sw::blank_type> ru; ru = (qi::char_(L"{") >> *(char_-char_(L"}")) >> char_(L"}")) % qi::eol; vector<vector<wchar_t>> result; qi::phrase_parse(s.begin(), s.end(), ru, sw::blank, result); for (auto& v : result) { //cout << "Size of string: " << v.size() << endl; for (auto& s : v) { wcout << s; }; cout << endl; }; std::cout << "Size of result"<<result.size()<<endl ; } However ouput is: { "id":23,"text":"sf sf" } { "id":23,"text":"sfsf" } Size of result6 It looks like that "{" becomes a single element of type vector<wchar_t> for the outer vector. Then consider the rule: *ru = (qi::char_(L"{") >> *(char_-char_(L"}")) >> char_(L"}")) % qi::eol;* According to the documentation, *(char_-char_(L"}")) should be vector . And because *a: A, b: vector --> (a >> b): vector *, then I think that *(qi::char_(L"{") >> *(char_-char_(L"}")) >> char_(L"}"))* should be *vector<wchar_t>*. This is contracdicted to the result. Where I'm wrong? -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Users-f2553780.html

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[interprocess] Determine size of managed_shared_memory
by Kai Benndorf 12 Oct '19

12 Oct '19

Hi all, I want to create a managed_shared_memory in exactly the size I needed. Therefore I do something like this: size = sizeof( common_managed_shared_memory ); size += sizeof( MyClassInSharedMem ); managed_shared_memory segment(create_only, "name", size ); MyClassInSharedMem allocates itself some memory by segment->allocate(). I added this also to the size, but get a boost::interprocess::bad_alloc exception on allocating this additional memory. Are there some magic bytes I forgot to add? Many thanks in advance Kai

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