October 2019 - Boost-users - lists.preview.boost.org

Boost.Numeric.Interval: Please specify rounding control mechanism
by Bastien Commelongue 01 Dec '20

01 Dec '20

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

2 1

Building with CMake?
by Robert Dailey 25 Nov '19

25 Nov '19

I see that individual repositories like boostorg/filesystem on Github have a CMakeLists.txt. But the boostorg/boost super repo doesn't have a root CMakeLists.txt. Either this doesn't follow standard CMake structure or there's no way to build with CMake globally instead of bjam. How can I build the boost libraries with CMake?

9 15

[preprocessor] increase tuple size
by pavel b 07 Nov '19

07 Nov '19

Hi, preprocessor/config/limits.hpp limits tuple size to 64 elements. Changing the BOOST_PP_LIMIT_TUPLE in this file seems not to have any effect. Is it possible to increase the maximal tuple size? Are there scripts to update dependent macros like BOOST_PP_TUPLE_ELEM_* in preprocessor/tuple/elem.hpp? Thanks in advance

3 7

Interest in a Unicode library for Boost?
by Zach Laine 04 Nov '19

04 Nov '19

About 14 months ago I posted the same thing. There was significant work that needed to be done to Boost.Text (the proposed library), and I was a bit burned out. Now I've managed to make the necessary changes, and I feel the library is ready for review, if there is interest. This library, in part, is something I want to standardize. It started as a better string library for namespace "std2", with minimal Unicode support. Though "std2" will almost certainly never happen now, those string types are still in there, and the library has grown to also include all the Unicode features most users will ever need. Github: https://github.com/tzlaine/text Online docs: https://tzlaine.github.io/text If you care about portable Unicode support, or even addressing the embarrassment of being the only major production language with next to no Unicode support, please have a look and provide feedback. I gave a talk about this at C++Now in May 2018, and now it's a bit out of date, as the library was not then finished. It's three hours, so, y'know, maybe skip it. For completeness' sake: https://www.youtube.com/watch?v=944GjKxwMBo&index=7&list=PL_AKIMJc4roVSbTTf… https://www.youtube.com/watch?v=GJ2xMAqCZL8&list=PL_AKIMJc4roVSbTTfHReQTl1d… Zach

11 30

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

2 4

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

2 2

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/>

1 0

[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!

1 0

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 _________________________________________________________________________________

2 1

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]

2 1

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

3 7

[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

1 0

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

1 0

[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

3 2

[outcome] Major changes for Boost 1.72 release
by Niall Douglas 10 Oct '19

10 Oct '19

Just as a heads up to those who care, and any pretesting of these changes in advance of the Boost release is welcome. There are two breaking changes: 1. The git submodule mechanism used by standalone Outcome of specifying dependent libraries has been replaced with a cmake superbuild of dependencies mechanism instead. Upon cmake configure, an internal copy of quickcpplib will be git cloned, built and installed into the build directory from where an internal `find_package()` uses it. This breaks the use of the unconfigured Outcome repo as an implementation of Outcome, one must now do one of: 1. Add Outcome as subdirectory to cmake build 2. Use cmake superbuild (i.e. `ExternalProject_Add()`) to build and install Outcome into a local installation. 3. Use one of the single header editions. 2. For standalone Outcome, the current compiler is now checked for whether it will compile code containing C++ Concepts, and if it does, all cmake consumers of Outcome will enable C++ Concepts. Set the cmake variable `CXX_CONCEPTS_FLAGS` to an empty string to prevent auto detection and enabling of C++ Concepts support occurring. There are two new features: - Standalone outcome is now `make install`-able, and cmake `find_package()` can find it. Note that you must separately install and `find_package()` Outcome's dependency, quickcpplib, else `find_package()` of Outcome will fail. - Support for C++ Coroutines has been added. This comes in two parts, firstly there is now an `OUTCOME_CO_TRY()` operation suitable for performing the `TRY` operation from within a C++ Coroutine. Secondly, in the header `outcome/coroutine_support.hpp` there are implementations of `eager<OutcomeType>` and `lazy<OutcomeType>` which let you more naturally and efficiently use `basic_result` or `basic_outcome` from within C++ Coroutines -- specifically, if the result or outcome will construct from an exception pointer, exceptions thrown in the coroutine return an errored or excepted result with the thrown exception instead of throwing the exception through the coroutine machinery (which in current compilers, has a high likelihood of blowing up the program). Both `eager<T>` and `lazy<T>` can accept any `T` as well. Both have been tested and found working on VS2019 and clang 9. More detail can be found at: https://boostorg.github.io/outcome/changelog.html Niall

1 0

Regarding the End of life of Boost version 1.56
by kamallochan Jena 05 Oct '19

05 Oct '19

Hi, In one of our project we are using Boost 1.56 version. And want to upgrade Boost C++ to a version that is not in an end of life state. My queries are: 1> When is the End Of Life of Boost 1.56 version ? 2> What is the latest stable Boost version we can use instead of Boost version 1.56 ? Can someone help on answering those questions. Thank you in advance! Thanks & Regards, Kljena

2 2

boost::geometry: intersection of a point with a linestring
by Giorgino R 04 Oct '19

04 Oct '19

Hi there, Is there any boost functionality to "split" a linestring with an intersecting point? I was expecting that boost::geometry::intersection could return a multi-linestring (of size two) or a vector of linestrings (size two). For example, please see a very simple case below which doesn't compile: point_2d pt(0.5, 0); > linestring_2d ls({ point_2d(0, 0), point_2d(1, 0), point_2d(3, 0), > point_2d(5, 0) }); > std::vector<linestring_2d> inter; > bg::intersection(pt, ls, inter); Is there any way to get inter vector with two linestrings (linestring_2d({point_2d(0, 0), point_2d(0.5, 0) }) and linestring_2d({point_2d(0.5, 0), point_2d(1, 0), point_2d(3, 0), point_2d(5, 0) }) ) or any multi geometry container that will hold the spatial information of two lines connected in this point? Or should I create these two lines myself by working out which points of the linestring are left and right of the intersecting point? Many thanks in advance.

2 3