October 2016 - Boost - lists.boost.org

A GUI Library
by jinhao 09 Nov '17

09 Nov '17

Hi, all I am developing a GUI library, it takes aim at easy-to-use and portable library for modern C++ methods. The project at http://stdex.sourceforge.net A git repository at http://nanapro.codeplex.com A brief at http://nanaproject.wordpress.com/2011/12/16/preliminary-study-of-nana-c-lib… Is there any interest in this library? Regards Jinhao

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Re: [boost] Boost CRC maintainer (Daryle Walker) missing in action?
by Olaf van der Spek 19 Jun '17

19 Jun '17

Hi Daryle, Any luck on your new setup? Gr, Olaf On Mon, Nov 28, 2011 at 1:11 AM, Daryle Walker <darylew(a)gmail.com> wrote: > I can look at it once I've finished my new setup. > > I had to reset my computer after a partial crash years ago. I never > got around to recreating my programming setup. My computer had been > at its maximum Operating System level back then, which is now 3 > versions behind. For the past few months, I've had my sister's old > laptop, with Windows Vista, and am trying to add a programming setup > to it now. > > > On Tue, Nov 22, 2011 at 7:18 AM, Beman Dawes <bdawes(a)acm.org> wrote: >> Hi Daryle, >> >> This guy has volunteered to take over maintenance of Boost CRC. Should >> we take him up on his offer? > >> ---------- Forwarded message ---------- >> From: >> Date: Wed, Nov 2, 2011 at 7:51 AM >> Subject: [boost] Boost CRC maintainer (Daryle Walker) missing in action? >> To: boost(a)lists.boost.org >> >> >> Hi, >> >> It looks like the Boost CRC maintainer (Daryle Walker) is missing in action? >> >> No response to tickets from the past 3 years. What's the procedure in this case? >> >> https://svn.boost.org/trac/boost/ticket/2492 >> https://svn.boost.org/trac/boost/query?component=crc&col=id&col=summary&col… > > -- > Daryle Walker > Mac, Internet, and Video Game Junkie > darylew AT gmail DOT com -- Olaf

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[beast] Request for Discussion
by Vinnie Falco 12 Jun '17

12 Jun '17

Beast provides low level HTTP and WebSocket interfaces built on Boost.Asio, the project is here: https://github.com/vinniefalco/Beast The plan is to solicit feedback from the Boost community before submitting a request for a formal review. First a brief update: I have attended CppCon 2016 and provided a 15 minute Lightning Talk on the library. There should be a video up at some point with all the talks, including mine. I spread the word about Beast and discovered that there are several folks in the wild already using the library and happy with it. There are also a couple of commercial products that are using it. One point brought up during the conference is that Beast does not offer sufficient higher level HTTP functionality. This omission is intentional. It is my idea to offer the building blocks (serializing and deserializing HTTP/1 messages, in synchronous and asynchronous flavors, and a universal HTTP message model), upon which other developers more knowledgeable than me could build those interfaces. The higher level pubic operations requested were: 1. Perform HTTP GET or POST and receive the response. Presumably this would handle both plain and TLS connections, handle redirects, and handle HEAD requests. Not sure about traversing proxies. 2. Expose an asynchronous HTTP server class which callers can instantiate with some sort of handler that returns the HTTP response given a request. It should be possible, in a minimal number of lines, to quickly get a server up and running. The requestor informed me that this functionality did not need to provide every possible feature or handle every use case. It just needed to handle the common use-cases. For the record, I am against this higher level functionality for a number of reasons. The higher the level of functionality, the more contentious the feature becomes, and the harder it is to satisfy a quorum of reviewers. No one would dispute that we need the ability to read a complete HTTP message from a socket. But not everyone will agree that a HTTP server needs an option to allow multiple listening sockets with different level of permissions. Another problem with offering higher level functionality is that it could be less likely to be approved for standardization in the C++ standard library. For example, the attributes of ease of use and fully functional oppose each other. If the functionality offered by a hypothetical std::http::client is not sufficient, a developer would be forced to write their own with little possibility to reuse parts of the implementation from the stdlib. I doubt the committee would approve of such a thing. I know I wouldn't. Admittedly I have little experience or knowledge on what would or would not get approved. A point was raised that a low-level-only HTTP implementation in Boost has the potential to discourage new users that need to perform simple operations like HTTP GET from using Boost in the future, given that robustly handling such operations would require the developer to write a significant amount of code. I can see some validity here. On the other hand, if Boost.Asio was submitted for a formal review today, would those same points be raised? Would Asio get rejected because it doesn't offer public interfaces for doing simple tasks like requesting an object from a web server? I wonder if perhaps the Boost formal review process has become defective. For reference here is what the current API offers: Example program that performs HTTP GET, then receives and prints the response: https://github.com/vinniefalco/Beast/blob/master/examples/http_example.cpp This is a high performance asynchronous HTTP server that serves local files as static pages. It is not an official API, it is part of the examples. Users who want a server need to copy the source code and modify it to suit their needs: https://github.com/vinniefalco/Beast/blob/master/examples/http_async_server… My initial purpose for requesting this discussion is two-fold: 1. Determine the level of consensus on the issue that Beast needs to do more for HTTP than the lowest level of functionality (reading and writing messages). I'm open to hearing all arguments for and against. 2. Get feedback on what official public interfaces to higher level functionality might look like. Specifically, a client that handles GET and POST, and a generic asynchronous server. And what features those interfaces would support. For example, is traversing a proxy a necessary feature for an official client interface? The best answers would provide function signatures or class declarations using the existing Beast HTTP types. In case its not clear, I am asking stakeholders and reviewers to help design the library. I'll open a discourse on the HTTP client to illustrate the proposed style of discussion: We want to provide a HTTP client implementation that lets users perform simple tasks like fetch a resource from a remote host. Calling code should be compact, letting people get their job done without getting mired in boilerplate. Here's a possible signature with example use: response_v1<string_body> get(std::string const& url, error_code& ec); error_code ec; auto res = get("http://boost.org", ec); if(! ec) std::cout << res; else std::cerr << ec.message() << '\n'; The get function would automatically perform the name resolution, connect the socket, request the resource with uri "/", and return the result. There's a problem here though, the caller is forced to use a message with std::string as the container for the body. An obvious fix is to add a template parameter: template<class Body = string_body> response_v1<Body> get(std::string const& url, error_code& ec); Better, but what if the body is not DefaultConstructible? We can add some parameters to forward to the Body constructor: template<class Body = string_body, Args&&... args> response_v1<Body> get(std::string const& url, error_code& ec, Args&&... args); We're getting somewhere now. Most users will use the default body, while an option exists for advanced users. But the implementation of get now has a complication. If an error occurs, it still has to construct a return value. This problem is likely surmountable but lets table it and start a new line of reasoning. What if the URI indicates https, e.g. "https://boost.org"? We can hide that under the hood by using a separate code path that uses asio::ssl::stream instead of ip::tcp::socket. But how does the caller provide the root CA certificates? How does the caller provide a client certificate? We are left with a client that satisfies two thirds of users but is unusable for the remaining one third. Is this Boost worthy? Is this std-lib worthy? I think not. Lets revisit the SSL issues later and think about a new problem. What happens to the socket when the request is done? In the proposed interface, the socket is destroyed. This means you can only make one request on a connection. At this point, I think its clear that the current interface is a non-starter. Here's a better idea. Lets define a class called client and make get a member function. Now we can have state, including configurable settings with reasonable defaults. class client { public: template<class Option> void set_option(Option&&); template<class Body = string_body, Args&&... args> response_v1<Body> get(std::string const& url, error_code& ec, Args&&... args); }; client c; error_code ec; auto res = c.get("http://boost.org", ec); if(! ec) std::cout << res; else std::cerr << ec.message() << '\n'; We still have some of the original problems, but other problems are solved. The class can keep the socket around, so that a subsequent call to get with the same server will use the already-open socket. The caller can set options on the client object instance before invoking get, such as any TLS certificates. Unfortunately we have new problems. Where is the io_service? If the class creates it for you, how many threads? How do I use my existing io_service, or is that even necessary? The class interface allows the connection to be kept alive but what if now the caller wants to close it (i.e. specify "Connection: close" in the request)? And there are some problems which are applicable to any interface. How does the caller adjust the parser options, for example change the limit on the size of the body? What if the caller wants the request made using a specific HTTP version? How does this handle basic authentication? How can the caller adjust the headers in the request? etc... This is why I think that offering a HTTP client is a rabbit hole which can only lead to a rejected formal review. Or maybe I am overthinking this? I'd love to hear proposed solutions to the issues (which could be just to say "forget about those features"). Despite my objection I have started work on these features anyway. Here are the beginnings of a HTTP client: https://github.com/vinniefalco/Beast/blob/88b485df7e6216282842f40cf99cc75de… Here is some work on a generic server: https://github.com/vinniefalco/Beast/blob/server/extras/beast/http/async_se… Please reply to this thread instead of starting a new thread, and keep the subject line prefix (e.g. "Re: [boost] [beast] ...") Thank you

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[msm] [statechart] unmerged PRs
by András Kucsma 23 May '17

23 May '17

Hi Everyone, There are a couple of PRs for msm and statechart by me and others, which didn't get any attention for many months now. Can the maintainers please take a look at them? https://github.com/boostorg/msm/pulls https://github.com/boostorg/statechart/pulls Thank you, Andras

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[clang] clang-cl expansion of macros
by Edward Diener 29 Apr '17

29 Apr '17

You can get clang-cl ( clang-win ) to show its VC++ emulated expansion of macros somewhat by passing the c++ option '-fmacro-backtrace-limit=0' to the compiler. It is still blessedly difficult to see the what and the why of clang's error messages when expanding macro using clang-cl, but at least it gives you a better chance of understanding where clang's emulation of VC++ has gone wrong. I have posted bug 27380 to the llvm/clang bug tracker at https://llvm.org/bugs/show_bug.cgi?id=27380 showing the main failure in VC++ emulation which I see when testing Boost PP with clang-cl.

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[container] moving a pre-built vector into a flat_set
by Sam Kellett 12 Mar '17

12 Mar '17

a common problem i encounter is that i have two stage's w/r/t to a large collection of data: building and querying. vector is obviously the king of building. flat_set is the king of querying. so what i often tend to do is build up a very large vector, sort it then create a flat_set using the flat_set(ordered_unique_t) constructor. however this still copies the entire vector into the flat_set, right? what i would like to be able to do is move the vector straight into the flat_set, something like: std::vector<T> data; flat_set data_set1(std::move(data)) // move vector in and sort it // or: std::sort(data.begin(), data.end()); // sort vector flat_set data_set2(ordered_unique_t, std::move(data)) // and move it in is this doable (am i just being blind?) or is there plans/interest for this?

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[nowide] Library Updates
by Artyom Beilis 04 Mar '17

04 Mar '17

Hello, Disclaimer: --------------- I recently discovered that virtually all e-mails sent from Yahoo account to any mailing lists go to user's spam due to recent Yahoo's DMARC policy. So I'm sending some important stuff from GMail account that almost certainly was missed: What is Boost.Nowide: -------------------------------- Boost.Nowide is a library that make cross platform Unicode aware programming easier. The library provides an implementation of standard C and C++ library functions, such that their inputs are UTF-8 aware on Windows without requiring to use Wide API. It was inspiration and inspired by http://utf8everywhere.org/ development ideas and policy. Some updates regarding Boost.Nowide ------------------------------- 1. Library moved to github and its format is converted to modular boost layout: https://github.com/artyom-beilis/nowide 2. Fixed unsupported std::ios::ate flag by boost::nowide::fstream 3. Added some C++11 interfaces to boost::nowide::fstream 4. Added integration functionality with boost::filesystem: https://github.com/artyom-beilis/nowide/blob/master/include/boost/nowide/in… Note: that the links to the source code on review schedule aren't relevant, it should be: - Code: https://github.com/artyom-beilis/nowide - Documentation: http://cppcms.com/files/nowide/html/ Also the library is still looking for review manager. Artyom Beilis P.S.: I'm sorry if you are getting this as "duplicate"

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[teeks] Missing winerror.h for MSVC-9
by Andrey Semashev 17 Feb '17

17 Feb '17

Hi, I see lots of tests failing on teeks99-09b-win2012R2-64on64, MSVC-9.0 because winerror.h is missing. Here's an example: http://www.boost.org/development/tests/develop/developer/output/teeks99-09b… I can see that the file is present in Windows SDK 6.0A, which is supposed to be used with this compiler. The tests are passing on my machine. Could this be a tester configuration issue? Also, all MSVC-15 tests are failing on teeks99-09o-win2012R2-64on64 with the error of 'cl' not being found.

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Why is this message in Spam?
by Olaf van der Spek 26 Jan '17

26 Jan '17

Hi, > Why is this message in Spam? It has a from address in microsoft.com but has failed microsoft.com's required tests for authentication. Learn more I think this list isn't configured properly.. and this causes some messages to end up in Spam consistently.. Who's responsible for the mailing list infrastructure? Gr, -- Olaf

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bad include guards
by Steven Watanabe 26 Jan '17

26 Jan '17

AMDG The following pairs of files have identical include guards ./boost/concept_check/general.hpp ./boost/concept/detail/msvc.hpp ./boost/concept_check/msvc.hpp ./boost/concept/detail/msvc.hpp ./boost/filesystem/cerrno.hpp ./boost/cerrno.hpp ./boost/interprocess/containers/tree.hpp ./boost/interprocess/containers/detail/tree.hpp ./boost/mpl/min_max.hpp ./boost/mpl/max.hpp ./boost/mpl/vector/aux_/front.hpp ./boost/mpl/list/aux_/front.hpp ./boost/multi_index/identity_fwd.hpp ./boost/multi_index/identity.hpp ./boost/python/pointee.hpp ./boost/python/detail/pointee.hpp ./boost/spirit/phoenix/closures.hpp ./boost/lambda/closures.hpp ./boost/xpressive/proto/v1_/proto_typeof.hpp ./boost/xpressive/proto/proto_typeof.hpp ./libs/config/test/boost_no_dep_nested_class.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/config/test/boost_no_mem_templates.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/config/test/boost_no_std_allocator.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/conversion/test.hpp ./libs/any/test.hpp ./libs/interprocess/example/print_container.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/interprocess/test/expand_bwd_test_template.hpp ./libs/interprocess/test/allocation_test_template.hpp ./libs/interprocess/test/printcontainer.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/interprocess/test/print_container.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/iostreams/test/detail/utf8_codecvt_facet.hpp ./boost/detail/utf8_codecvt_facet.hpp ./libs/regex/test/regress/test_regex_search.hpp ./libs/regex/test/regress/test_partial_match.hpp ./libs/serialization/test/C.hpp ./libs/serialization/test/A.hpp ./libs/xpressive/perf/regex_comparison.hpp ./libs/regex/performance/regex_comparison.hpp ./tools/inspect/time_string.hpp ./tools/common/time_string.hpp In Christ, Steven Watanabe

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Generating Boost documentation with pandoc
by Vinícius dos Santos Oliveira 18 Jan '17

18 Jan '17

Has anyone tried to generate Boost-styled documentation using pandoc? I never fully liked PDF documentation because I never actually print documentation. However, a few weeks ago I got an ebook reader and I've been fascinated by the ePUB format. I'm using it to read even the IETF's RFCs and it's very pleasant. I'm using ePUB to read files even on my usual laptop. Anyway, I was wondering how nice would be to have an ePUB file containing the whole Boost documentation. pandoc has docbook support as one of its input formats and is capable of generating great ePUB output. -- Vinícius dos Santos Oliveira https://vinipsmaker.github.io/

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Re: [boost] [process] Formal Review starts today, 27 October
by Bjorn Reese 04 Dec '16

04 Dec '16

On 10/27/2016 08:26 AM, Antony Polukhin wrote: > - Whether you believe the library should be accepted into Boost > * Conditions for acceptance I withhold judgement for now to give the author an opportunity to respond. At the moment I am unsure whether to vote for conditional acceptance or rejection. > - Your knowledge of the problem domain Advanced on Unix. > You are strongly encouraged to also provide additional information: > - What is your evaluation of the library's: > * Design I have a couple of serious concerns. My first concern is about the use of tagged arguments, and especially the redirection operators, in constructors. Instead I propose that the library uses the Named Parameter idiom (see [1], not to be confused with what Niall labelled "tagged name parameter" idiom.) The bp::child object should not execute in the constructor, but rather via operator(). That way we can use the named parameter idiom to build up redirections and similar modifications. For example: auto compile = bp::child("c++").output(bp::null); compile("main.cpp"); // Executes My second concern is about deadlocking. The FAQ shows two ways of deadlocking. I would expect the latter (the ls example) to work without further ado because that is how any newcomer would write their code. My third concern is about the chaining of pipes between processes. The tutorial shows an example where the output of the nm command is forwarded to the c++filt command. However, the forwarding is not done directly from the nm process to the c++filt process, but goes via the parent process. This can incur a performance degradation when nm generates much output. Is it possible to chain them directly? Besides "nm myfile | c++filt" that is. I also have the following minor comments / questions. Is it possible to redirect stderr to stdout? (like 2>&1). The reference documentation only mentions this under asynchronous pipe output. The bp::starting_dir should be renamed to bp::current_path to be consistent with Boost.Filesystem. Consider renaming bp::spawn to avoid confusion with boost::asio::spawn which is how you launch coroutines with Boost.Asio. I am missing a this_process::get_id() function to return the current process identifier. > * Implementation My major concern with the implementation is that the library is only header-only, so I cannot compile it as a static library if I wish to. There are several Boost header-only libraries that allows you to do that. The reason why I find this important for Boost.Process is because I want to avoid getting platform-specific C header files included into my project when I include a Boost.Process header. The library should throw its own process_error exception which inherits from system_error, similar to Boost.Filesystem. I did not investigate the implementation in greater detail. > * Documentation The documentation is lacking an entire chapter with an overall description of the library and the concepts used. For instance: * What are processes and pipes? * What are the possible invocation mechanisms? Some of this is mentioned in the Design Rationale, but that is not the place where developers seek their information. * How to set search paths or the current working directory. * How to use environment variables. * this_process Tutorial / Synchronous I/O: What is the default behaviour when I/O redirections are not specified? Tutorial / Asynchronous I/O: Consider including an example with boost::asio::spawn as a way to obtain the yield context. Reference / child: Does not mention how the life-time of the object and the child process are related. For instance, the documentation on the destructor only mentions that it is a destructor. Reference / cmd: bp::cmd will parse the input string as a sequence of space-separated arguments. Is it spaces or whitespaces? Is it possible to have escapes for arguments that do contain spaces? > * Tests Did not investigate. > * Usefulness A process library is a very useful addition to Boost. > - Did you attempt to use the library? If so: > * Which compiler(s) > * What was the experience? Any problems? Did not try. > - How much effort did you put into your evaluation of the review? About 4-5 hours (one of which was gratuitously donated by daylight saving time.) [1] https://en.wikibooks.org/wiki/More_C%2B%2B_Idioms/Named_Parameter

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[MPL] A Proposal
by Bruno Dutra 16 Nov '16

16 Nov '16

Dear Community, About a year ago today, there was a proliferation of threads [1][2][3] in this mailing list concerning the future of Boost.MPL, or even whether it had a future at all, and opinions diverged widely on the matter. Many have expressed concerns about the fact Boost.MPL was long outdated and proposed major changes to open path for modernization, while some others argued against it, fearing unexpected and disastrous side-effects could propagate throughout the rest of Boost. A few questioned if it was worth it at all to spend any further resources on Boost.MPL given the fact new alternatives were coming up, such as Boost.Hana, which departed entirely from template metaprogramming, yet some argued TMP remained a competitive alternative for type computations in C++14 as it has been demonstrated by Peter Dimov in his impressive articles [4] on modern TMP. Amidst all this, a proposal by Robert Ramey [5] caught my attention and inspired me to develop what I call Metal [6], a template metaprogramming library designed on the same core principles as Boost.MPL, but written from the very beginning to take full advantage of C++11. Metal was not designed to be a strict drop in replacement for Boost.MPL though, it was rather meant to be regarded as a modern version of Boost.MPL's original API, diverging only where it could really benefit from modern C++ and that essentially means gains of several orders of magnitude in performance** and lower memory consumption. At this point Metal is very close to where I originally intended to bring it and I think it's time I gauge interest from the community on a modest proposal I've been maturing along the past year. As a modern approach to the same task that Boost.MPL was meant to address, I don't believe Boost would benefit at all from yet another TMP library that would essentially compete with Boost.MPL and even Boost.Hana in some cases, specially as maintainers of older code that depends on Boost.MPL would have to go through major refactoring efforts in order to benefit from such an addition to Boost. I would like to propose something different instead. My proposal is to make Metal officially into a new revision of Boost.MPL's API, essentially MPL2 as the original proposal by Robert Ramey put it, merging both into one single TMP library. The idea would be to provide a thin proxy for the current Boost.MPL API which would have two backends configurable by preprocessor switches: the original implementation and a another one based on Metal. This way older code using Boost.MPL could see immediate gains on performance by selecting the newer backend on supported compilers, while at the same time legacy code maintained on older compilers could still rely on Boost.MPL's impressive ability to run virtually anywhere. On the other hand, newer projects interested on pure type computations would have the newer API entirely available to them. This proposal also overcomes the problem of dealing with the maintainability of Boost.MPL, since it provides a way for smooth transition from legacy hacks required by ancient compilers into a cleaner and easier to maintain C++11 codebase, besides avoiding any breaking changes within existing code in the process. Furthermore, should this proposal make it into Boost, I would be naturally willing to take responsibility for the maintenance of Boost.MPL, which AFAIK has been maintained by the CMT for quite some time now, often with limited resources. Comparing Metal and Boost.MPL there are a few noteworthy differences. Metafunction Classes have proven themselves entirely unnecessary and have thus been removed altogether in favour of pure Lambdas (in the Boost.MPL sense). Moreover, iterators make little sense in a functional world, so these too have been removed despite the fact they may easily be emulated in the new design. Moreover Metal develops the concept of optionals, that is, its metafunctions only have a nested ::type defined when they may be successfully computed, what may be safely tested using metal::is_just and may also be used to SFINAE out of miscomputations. Finally I'd like to point out that Metal was designed to be portable across as many compilers as possible and three of the most popular ones are continuously tested using Travis and Appveyor: Clang 3.5+, GCC 4.8+ and MSVC 14 (2015). I hope this is a reasonable proposal and I look forward into your opinions about it. ** Even though I haven't published any benchmarks yet, an example follows just to back my claims regarding performance (just tested on my personal laptop running linux): //Generate a list containing 10 thousand instances of std::integral_constant, from 0 to 9999 using l = metal::enumerate_t<metal::integer<10000>>; // GCC 5.3 ~0.4 s // Clang 3.7 ~0.5 s //Transform a list containing 5 thousand numbers by squaring each element using l1 = metal::enumerate_t<metal::number<long long, 5000>>; using l2 = metal::transform_t<metal::pow<metal::_1, metal::integer<2>>, l1>; // GCC 5.3 ~5.6 s // Clang 3.7 ~3.0 s [1]: http://thread.gmane.org/gmane.comp.lib.boost.devel/257680 [2]: http://thread.gmane.org/gmane.comp.lib.boost.devel/257983 [3]: http://thread.gmane.org/gmane.comp.lib.boost.devel/258843 [4]: http://pdimov.com/cpp2/simple_cxx11_metaprogramming.html [5]: http://rrsd.com/blincubator.com/bi_suggestion/mpl-lite-or-mpl2/ [6]: http://brunocodutra.github.io/metal/ Regards, Bruno Dutra

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interest in structure of arrays container?
by Michael Marcin 06 Nov '16

06 Nov '16

Structure of arrays is a pretty well known pattern for improving memory density and enabling vectorization in high performance code. Also known as parallel arrays[1]. After hand-rolling yet another of these it occurred to me that you make a reasonable first implementation with a simple alias template. template< typename... Ts > using soa = std::tuple< std::vector<Ts>... >; example: soa<int,float,std::string> data; This is decent start but has several issues including: * nothing to preserve the invariant keeping the arrays the same length * missing coalesced interface for vector methods (size, reserve, etc) * no iterator * wasted storage for duplicated allocators, capacities, sizes * sizeof...(Ts) allocations could be a single large block The work required to address these issues is not too great I think. Potential names: soa<Ts> structure_of_arrays<Ts> parallel_array<Ts> struct_array<Ts> parallel_vector<Ts> struct_vector<Ts> Does this already exist somewhere? Does it seem useful? [1]https://en.wikipedia.org/wiki/Parallel_array

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[process] Formal Review starts today, 27 October
by Antony Polukhin 05 Nov '16

05 Nov '16

Dear Boost community, The formal review of Klemens David Morgenstern's Process library begins today, 27th October and ends on 5th November. Process is a C++11 library to manage system processes. It can be used to: * create child processes * setup streams for child processes * communicate with child processes through streams (synchronously or asynchronously) * wait for processes to exit (synchronously or asynchronously) * terminate processes Full documentation with examples and tutorial is available at http://klemens-morgenstern.github.io/process/index.html Stable source codes for review are available at https://github.com/klemens-morgenstern/boost-process/tree/boost_review Latest source codes available at https://github.com/klemens-morgenstern/boost-process We encourage your participation in this review. At a minimum, kindly state: - Whether you believe the library should be accepted into Boost * Conditions for acceptance - Your knowledge of the problem domain You are strongly encouraged to also provide additional information: - What is your evaluation of the library's: * Design * Implementation * Documentation * Tests * Usefulness - Did you attempt to use the library? If so: * Which compiler(s) * What was the experience? Any problems? - How much effort did you put into your evaluation of the review? We await your feedback! -- Best regards, Antony Polukhin

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Curiousity question
by Edward Diener 01 Nov '16

01 Nov '16

I would like to ask a design question for any Boost developers or anyone on this mailing list who might care to answer. You are designing or working on a library, perhaps for Boost, perhaps for fun, and part of the design of the library has some public functionality taking a shared pointer as input. You: 1) Use boost::shared_ptr 2) Use std::shared_ptr 3) Use both boost::shared_ptr and std::shared_ptr with the same functionality 4) Use neither, you roll your own shared pointer-like functionality 5) You don't lke shared pointers and use raw pointers instead I really am curious about this. I haven't put any limitation on your library or made any presumption on who your library is for, on purpose. Thanks for anyone answering !

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[process] Formal Review starts today, 27 October
by Remi Chateauneu 31 Oct '16

31 Oct '16

Hi All, "Whether you believe the library should be accepted into Boost" It could be, but as some very important features are missinge, the implementation should be prepared from now on. "Your knowledge of the problem domain" About 20 yrs C++ development Linux and Windows. This library has a strong focus on the streaming which is quite rare and interesting. However, other very important features of multi-processing are missing should be planned: At least to ensure that, in the future, they can be added without breaking existing code. Example of these desired fatures are (Taken from my own needs) * List of subprocesses of a given process. * Get its parent pid (Already discussed). * Get the entire process tree of a machine. * It is very useful to be notified when a given process dies (unotify on Linux). * On windows, we have the feature e.startup_info.dwFlags = STARTF_RUNFULLSCREEN, which gives some control on the console, which Is very good. Could we have more documentation about it, and plans to have the same feature on Linux ? Generally speaking have some control on the process terminal if there is one. * Have some knowledge about users and user groups, as strings and integer identifiers: the concept is similar on Windows and Unix. * Have some control on process priority( Unix's nice command ) Indeed, many of these features are not portable, but most of time, developers use only a common core of features, which is quite enough. Maybe take inspiration from portable libraries such as Python psutil, which exposes a common interface for all operating systems. Interoperability: * It might be worth checking portability with other operating systems. BSD ? VMS ??? * Must ensure that this lib is interoperable with boost::interprocess (Concept of permissions might be worth using ?) * Does it build on pre-C++11 compilers ? Many projects are not able to upgrade to C++11 immediately and have to stick to previous C++ standard. Some critics (Nothing is perfect): * The merit of the ">" operator for optional arguments is to be visually similar to an indirection, but in the context of C++ programming, although elegant, it is I think confusing and could be mismatched with <> templates or comparisons. Creating a process is a not-so-frequent operation and we should not be afraid to be verbose and very clear, I believe. * Syntax ‘(bp::std_out & bp::std_err) > "output.txt"’ . Can we explain the exact difference with the syntax: ‘bp::std_out > "output.txt", bp::std_err > "output.txt"’’ * More comments in the code and examples please. * Examples async_io.cpp or arg.cpp do not build with boost 1.62: include\boost\process\detail\windows\compare_handles.hpp(24): error C2039: 'BY_HANDLE_FILE_INFORMATION_': is not a member of 'boost::detail::winapi' * ‘typedef basic_environment<wchar_t> wenvironment;’ : Is It really useful ?? POSIX getenv() only uses char. * Why is the class basic_environment so big, as it is basically a simple std::map< std::string, std::string > ? (Naïve question). Anyway, many congratulations for this very interesting work, which is definitely on the right direction. Regards

2 1

[gil] Some documentation links broken
by Edward Diener 31 Oct '16

31 Oct '16

In the documentation for Gil the links to the video tutorial, as well as the Information links on the left hand side of the initial page, are broken. Does anybody know if these links still exist anywhere ?

1 0

libstdc++ debug mode
by Robert Ramey 31 Oct '16

31 Oct '16

Back on May 2 2016 I made what I thought was an innocuous change to the serialization library build. I then forgot about it. I ran my tests and normal on my OSX set up for the compilers that I use there - clang and g++ 5.1 in various modes 03, 11 etc. Things seemed fine. I uploaded the develop branch as normal. Sometime later I discovered that all the gcc tests on linux platforms were failing with a segfault. Unfortunately time had passed and I couldn't run the tests myself so I never could figure out what the breaking change was. Lately I separated time to get to the bottom of this and in installed via Parallels ubuntu v 14 on my Mac as a guest operating system. After the usual back and forth getting stuff to work I was able to reproduce the problem. Running gdb indicated that things crashed with a call to boost::io::state_saver which led me to investigate THAT library which as it turned out is also failing all it's tests on the plaform. So thought I - no problem - all I have to do is to complain to the author of that library. But this didnt' workout a) I posted message and no one responded. b) I checked trac items and there was what seemed a related item. But it seemed a little hard to understand/fix and in any case, no one addressing it. I looked into just fixing it myself, but it looked to entail delving into the bowels of libstd++. So this dissuaded me as I have my own bowels to delve into. c) So I commented out references to boost::io::state_saver an ran some tests - and damn still failed. d) So I rolled back my source to the master dated 24 April 2016 and incrementally updated and ran some tests until I found the culprit. Needless to say, this is quite a tedious procedure. The issue seems to be that I added the following to the jamfile: <toolset>gcc:<define>_STLP_DEBUG <toolset>gcc:<define>_GLIBCXX_DEBUG The second adds a lot of checking. commenting this permitted tests to pass. Lesson of all this is: a) I'm thinking we should run all tests on the deelop branch with _GLIBCXX_DEBUG defined. That is, our jam files should contain?: <toolset>gcc:<variant>debug><define>_GLIBCXX_DEBUG b) it looks like when an error in libstd++ is encounted - things just segfault. I couldn't find the corresponding source in libstd++. GDB just bailed when I made a call to state_saver. c) boost::io::state_saver should be maintained. d) It would be helpful to be able to roll back the test matrix to any previous git version. That is, the results would be put into a database or datacube and we could scroll back and forth to see track down problems in test results. Robert Ramey

3 3

Review Manager needed for stacktrace library
by Antony Polukhin 27 Oct '16

27 Oct '16

Hello, Stacktrace is a C++98 library for storing and printing backtraces. Supports major platforms, does demangling, has API for accessing individual frames, supports hashing and comparison operators. Library: https://github.com/apolukhin/stacktrace Docs: http://apolukhin.github.io/stacktrace/index.html Anyone wishing to become the Review Manager for the library? -- Best regards, Antony Polukhin

8 21

[preprocessor] PR decision for Intel C++ 17 on up on Windows
by Edward Diener 27 Oct '16

27 Oct '16

I need some guidance from Boost developers in general. A PR has been issued for Boost PP which only affects Intel C++ 17 on up in Windows. I can ascertain that only this compiler in Windows is affectd by the PR. Needless to say I do not test this personally because it costs a decent amount of money to buy a license. Intel does graciously offer free licenses for Intel C++ on Linux for Boost developers and I have used it to test the compiler under Linux. Also there are no regression tests for Intel C++ on Windows in the 'develop' or 'master' regression test matrices. While the person who issued the PR ascertains that it fixes problems for Boost libraries he uses with Intel C++ 17 on Windows the nature of the PR is drastic enough that it could easily break other libraries if the changes in the PR does not correspond to Intel C++ preprocessing in all cases. So my quandary is what to do about the PR. The PR is at https://github.com/boostorg/preprocessor/pull/9#issuecomment-256741882. It is another one of these cases, like clang targeting VC++, where a compiler implementation on Windows wants to emulate the non-standard VC++ preprocessor but can't quite get it right ( as if emulating a broken preprocessor should ever be right ). Thoughts ? Ideas ? Suggestions ?

3 4

Boost odeint 1.62 link broken
by Daniel Duffy 27 Oct '16

27 Oct '16

________________________________________ From: Boost [boost-bounces(a)lists.boost.org] on behalf of Karsten Ahnert [karsten.ahnert(a)googlemail.com] Sent: 16 May 2016 15:08 To: boost(a)lists.boost.org Subject: Re: [boost] Boost 1.61.0 has been released > The Asio link http://www.boost.org/doc/libs/1_61_0/libs/asio/ is broken > (on http://www.boost.org/doc/libs/1_61_0/) I get ERR_TOO_MANY_REDIRECTS > with Chrome. The odeint link is also broken. I get "404 Not Found File "/home/www/live.boost.org/common/code/../../doc/archives/boost_1_61_0/libs/numeric/odeint/doc/html/index.html" not found. Unable to find file." Karsten _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost

2 1

[boost.process] Review
by Klemens Morgenstern 27 Oct '16

27 Oct '16

Boost.Process 0.6, as can be found here (https://github.com/klemens-morgenstern/boost-process) will be in review from October 27 to November 5. The review manager will be Antony Polukhin. Doc (http://klemens-morgenstern.github.io/process/) I really hope this library gets through the review, since boost (or C++ for that matter) really needs a process library. I would be really happy, if some of you could take the time to look into it - if you find any major issues, they might be addressed, before the actualy review. That would then increase the probability of the library getting accepted.

5 13

[release] 1.63.0 now closed for new libraries and breaking changes
by Daniel James 27 Oct '16

27 Oct '16

Hello all, The master branch is now closed for new libraries and breaking changes, and will be closing for major changes in a week (2nd Nov) and closed for the beta in two weeks (9th Nov). Also, if you're ready, you can also add your libraries' changes to the release notes at: https://github.com/boostorg/website/blob/master/feed/history/boost_1_63_0.q… thanks, Daniel

2 3

[fixed_point] First presentation from GSoC 2015 and more
by Christopher Kormanyos 25 Oct '16

25 Oct '16

Hello Boost developers, A partial implementation of fixed-point in a Boost-like style based on proposal N3352 is now available.This work is the result of developments from 2013-2016, including efforts from GSoC 2015. The source code is available at: fixed_point-masterPreliminary docs are available at: fixed_point-docWe are potentially interested in submitting this work for inclusion in Boost. We are now requesting comments and suggestions for improvements, corrections and any further test results if these become available.Some key library features include:* proper C++ header-only implementation * full numeric_limits and <cmath> functions * flexible template choice of split between resolution and range * automatic selection of underlying integral representation * portability and high efficiency for bare metal microcontrollers * interoperation with Boost.Math * seamless extension to high-precision using Boost.Multiprecision * extensive test suite Thank you for your consideration. Best regards,Christopher Kormanyos

7 22

[serialization] 2 blocking bugs
by alainm 25 Oct '16

25 Oct '16

Hi, My Boost.MPI builds are currently failing because of two blocking bugs in serialization (merge request 47 and 46). Could someone have a look please ? Thanks Alain

1 0

boost @ Meeting C++ 2016
by Jens Weller 24 Oct '16

24 Oct '16

Hello boost community, a short and final reminder, that the Meeting C++ conference is just a few weeks away! A few tickets are still available, here is the schedule: https://meetingcpp.com/index.php/schedule16.html The schedule also has the link to the student program and diversity tickets! Also there is still a few places available in the boost workshop with Boris Schäling and Michael Caisse. I plan to have a meetup for boost users in one of the breaks in the upper lounge, so that the boost communtiy is able to actually meet at Meeting C++! thanks, Jens Weller

1 0

Interest in chained relational operations
by Rahman Salim Zengin 24 Oct '16

24 Oct '16

Hi, The code in question is a simple chained comparison implementation. It works with any type If relational operators for that type is defined. https://github.com/rszengin/chain May some people find it useful?

4 4

predef: BOOST_COMP_MSVC defined for Gcc/Linux?
by Oliver Kowalke 24 Oct '16

24 Oct '16

Hi, test '#if defined(BOOST_COMP_MSVC)' evaluates to true with GCC on Linux. what I'm missing? Oliver

2 2

[interprocess] interprocess_condition blocks on notify_all if other process crashes
by Remi Chateauneu 22 Oct '16

22 Oct '16

When two processes share memory, and if one of them dies leaving a mutex in locked state, then the other process blocks on a notify using a interprocess_condition, stored in shared memory. This is described here: http://stackoverflow.com/questions/18240263/boost-interprocess-condition-bl… The reason is that this condition uses in general, a ipcdetail::spin_condition. Here is what it does in boost/interprocess/sync/interprocess_condition.hpp and boost/interprocess/sync/spin/condition.hpp : inline void spin_condition::notify(boost::uint32_t command) { //This mutex guarantees that no other thread can enter to the //do_timed_wait method logic, so that thread count will be //constant until the function writes a NOTIFY_ALL command. //It also guarantees that no other notification can be signaled //on this spin_condition before this one ends m_enter_mut.lock(); It locks an internal mutex, and if it is already locked and not unlocked by the crashed process, we are blocked. A fix is to replace lock() by: if( ! m_enter_mut.timed_lock(delay) ) throw an_exception(); A cleaner fix would be to derive a subclass from spin_condition to implement something like: bool derived_spin_condition::timed_notify(boost::uint32_t, ptime delay) What do you think ? Thanks.

2 1

[config] Changes to reflect Visual C++ "15" preview 5
by Beman Dawes 21 Oct '16

21 Oct '16

Boost.Config is current reporting these macros for msvc 14.0 update 3 and later: BOOST_NO_COMPLETE_VALUE_INITIALIZATION Xiang Fan of the VC++ compiler team kindly tested "15" preview 5 against boost without this macro is still getting errors. So this one is still needed. BOOST_NO_CXX11_HDR_CODECVT That's wrong. <codecvt> has been supplied at least since msvc 10.0. I'll submit a P/R. BOOST_NO_CXX14_AGGREGATE_NSDMI Here is a test program, based on the config docs: #include <cassert> struct Foo { int x, y = 42; }; int main() { Foo foo = { 1234 }; assert(foo.y == 42); assert(foo.x == 1234); } That now passed on "15" preview 5, so I'll summit a P/R. BOOST_NO_CXX14_CONSTEXPR The "15" preview 5 release notes say "The most notable compiler changes include complete support for generalized constexpr" I know from conversations with msft folks that they put a lot of effort into constexpr fixes, and that they would like bug reports if anyone is finds constexpr bugs with "15" preview 5. I'll submit a P/R. BOOST_NO_TWO_PHASE_NAME_LOOKUP This one still applies. The backstory has changed a lot, however. Enough progress has been made on the new parser that two phase name lookup should ship next year, and maybe even early next year. But don't hold your breath quite yet. Thanks to Andrew Pardoe for fact checking a draft of this post. --Beman

9 26

Review Manager needed for the C++14 Reflections Library that works Without Macro nor Markup (ex magic_get)
by Antony Polukhin 20 Oct '16

20 Oct '16

Hello, PFR is a C++14 library that represents POD structures as tuples and provides tuple-like methods for PODs. Library has a set of predefined operators for PODs and useful functions for everyday use. Works with user-defined types without any macro nor boilerplate code. Has additional (theoretical) features for C++17. Library: https://github.com/apolukhin/magic_get Docs: http://apolukhin.github.io/magic_get/ Boost Library Incubator: http://blincubator.com/bi_library/pfr-pod-flat-reflection/?gform_post_id=16… Anyone wishing to become the Review Manager for the library? -- Best regards, Antony Polukhin

3 3

[spirit][qi] How to write a boost::spirit::qi parser to do what '?' does in regex?
by Han Wang 19 Oct '16

19 Oct '16

Let's say we have a regex "start:(?: ([0-9]{1,2}))? ([0-9].*)". It will match std::string string1 = "start: 01 0ab"; and std::string string2 = "start: 0ab"; We can also get the 2 matched string respectively. I try to use boost::spirit::qi parser to parse string2 but it couldn't match. qi::rule<std::string::const_iterator, std::string()> rule1 = qi::repeat(1,2)[qi::digit]; qi::rule<std::string::const_iterator, std::string()> rule2 = qi::digit >> *qi::char_; std::vector<std::string> attr; auto it_begin = string2.begin(); auto it_end = string2.end(); if (qi::parse( it_begin, it_end, qi::lit("start:") >> -(qi::lit(" ") >> rule1) >> qi::lit(" ") >> rule2 >> qi::eoi, attr)) std::cout<<"match"<<std::endl; else std::cout<<"not match"<<std::endl; We can of course use a look-ahead operator to check what's behind rule1, but is there a more generic approach to implement regex operator '?' ? Thanks!

2 1

[container] small_flat_set and small_flat_map
by Sam Kellett 19 Oct '16

19 Oct '16

Given that Boost.Container has a small_vector now, would a piece of work that changed flat_set and flat_map to use small_vector<0> internally be feasible? I ask because I feel like if this was the case it would be almost trivial to expose flat_tree<N> through small_flat_set<N> and small_flat_map<N> types to provide the small size optimisation for these two containers.

5 8

Error in Review Schedule
by Emil Dotchevski 19 Oct '16

19 Oct '16

It seems like the entry for the Callable Traits library in http://www.boost.org/community/review_schedule.html links the PODs Flat Reflection documentation. Emil

2 1

Re: [boost] [fixed_point] First presentation from GSoC 2015 and more
by John McFarlane 19 Oct '16

19 Oct '16

> > Date: Thu, 13 Oct 2016 20:41:27 +0000 (UTC) > From: Christopher Kormanyos <e_float(a)yahoo.com> > > > I discuss P0106R0 (a revision to N3352) in my paper, the latest draft of > > which is always available here: https://github.com/ > > johnmcfarlane/fixed_point/blob/master/doc/p0037.md#p0106 > > I'm honestly not sure which approach is preferable overall. The set of > > features and qualities requested during SG14 and SG6 meetings is large > and > > conflicting. It includes minimal build times, minimal run-time overhead, > > every rounding and overflow strategy listed in P0105, decimal radix and > > support for specialized fixed-point instructions on embedded > architectures. > Hi John. Thanks for visiting this thread. > > My recommendation would be to limit the scope of the proposal > to a realistic level in the SGs so that we can end up with anything > at all within a reasonable time scale. We could consider back porting > some (but probably not all) of SG14's specified interface to Boost > if that helps move anything along. > A second pair of implementor eyes would be a huge help. I should point out that although it hasn't seen much attention lately, P0106 may still be active. (Frankly, the evolution of my design has been largely a process of slowly copying or facilitating all the most popular from Lawrence's proposal!) One problem P0037 faces - even if it were to be standardized - would be that alone, it only provides fixed-point arithmetic. It's designed to work with types that also solve arbitrary width, rounding and overflow but those types are not part of any proposal. In particular, without an arbitrary-width integer type, it's very difficult to use fixed_point<> safely. > > I was also wondering about decimal radix, but I don't know if it > might simply be better to identify those 80% of the most popular use cases and simply specify these. At least it would get the library > moving forward and people could use fixed-point in C++. This is basically what we tried to do with the GSoC project. > That makes sense. I at least want to have a solution which doesn't close the door on decimal in future additions. Here's my current plan: https://github.com/johnmcfarlane/fixed_point/blob/master/doc/p0037.md#non-b… > > >> In your work I've been experiencing some trouble with>> the division > routine. > > Can you elaborate? Was this recently? I've been trying out numerous > > strategies for arithmetic operators. My current preferred approach is to > > pad the left-hand operand before performing the division but that's only > > been checked in for a few months. > > I'm not sure about the design, and error on my side is a likely possibility. But division operator in the master branch seems like it does not pad before divide. This might give the wrong result. > I hope that's not the case but it's a tough operator to get right - especially with 32-bit operands. If you ever find a good example of this happening I'd be very interested in it. At least when using the elastic alias, precision loss should be avoidable (beyond inevitable approximation of rational numbers and x/0). tl;dr: The details of padding in the division operator follow... The padding is done on this line: https://github.com/johnmcfarlane/fixed_point/blob/91c3f2e272f9fd5e33ffb4dc2… It's on display in this test: https://github.com/johnmcfarlane/fixed_point/blob/1cc7ceaaff5422667ae962995… In the above test, the two operands have a single fractional digits. If operator/ did not pad the LHS, then the integer operation would be 126/8 which would lose precision. Instead, the LHS is promoted and shifted left by 8 bits. Then, integer division occurs and the value is stored with (hopefully!) no further shifts. > For division, I have used the following approach. * handle sign * extend n bits to 2n bits > * shift left by radix split plus one round bit * divide 2n / n -> n bits > * handle round and sign > So you're right this requires 64-bit extension for a 32-bit fixed-point unless you tackle the problem of two-component division, which I have done using a simplified version of Knuth long division. At the moment, this is only in develop branch. The compiler switch is BOOST_FIXED_POINT_DISABLE_WIDE_INTEGER_MATH. > This is core to the difference in approach between P0037 and P0106. I guarantee to use built-in integer math for any type specialized on built-in integers. I believe that types with arbitrary width can then be built upon this foundation using novel integer types. Here is an example using Boost.Multiprecision to express a Googol: http://johnmcfarlane.github.io/fixed_point/#boost fixed_point<> uses the same algorithm regardless of whether the `Rep` integer is an uint8_t or a 400-bit custom type. > > >> I also had some problems compiling on VC12 (but you don't target that > >> compiler anyway). So that's no big deal. > > > You will need a C++11-compliant compiler as sg14::fixed_point<> creates > > literal types. Lack of support for features like constexpr constructors > is > > the main obstacle to compiling under VC++ 2013 and earlier. > I actually agree with that approach. Either it uses C++11 or it does not. I don't see the need to cater to a specific older compiler for new library work. > It's a pragmatic choice. Three reasons are: * C++11 has everything I need to implement (with difficulty) a literal type. In particular, I can write most of my unit tests using `static_assert` which is the best thing ever! * Once you start returning novel specializations from your arithmetic operators, `auto` type deduction is essential to usability. * Many of my target users in SG14 are stuck with compilers which are behind the curve. > >> In your work you are using wrapped versions of elementary transcendental > >> functions designed for built-in float. You might appreciate our > hand-crafted > >> functions designed to be highly efficient in several digit ranges. > > > Yes! I would be very interested in seeing if I could adapt those > function. > We worked hard on these. And there are many good algorithms available in boost/fixed_point/fixed_point_negatable_cmath.hpp > > Having spent a non-trivial amount of time writing the simplest sqrt I could find, I appreciate the effort this must have involved. > Mine are placeholders and I've deliberately postponed the non-trivial task > > of adding cmath equivalents. It's come up - maybe a couple of times - > > whether these functions are desired and the response has been to just > keep > > the proposal narrow so they are not included. > > > There are interesting questions regarding how to implement some > functions. > > For example, you surely don't always want the same inputs and outputs > from > > functions involving angles. And hopefully these functions can be > constexpr > > - unlike existing functions. > I agree. > > Also, how have you approached the trade-off between speed and accuracy? I > > went for a very simple sqrt function which is adequate if the value is > > calculated at compile time but is likely not desirable at run-time. This > > isn't a problem that floating-point variants face. > > The elementary transcendental functions use many techniques including polynomial approximation, Pade approximation, Taylor series, > Newton iteration. For low digit counts, mostly polynomial approximation. We > express the coefficients directly as integral values of the fixed_point > representation and avoid as much as possible full division and multiply, > favoring integer div and mul. These functions are quite efficient. We have > not constexpr-ed them. But it looks like there is potential for that. > Writing constexpr functions in C++11 can be a big challenge. > > >> I have also benched our fixed_point on bare-metal embedded systems both > >> 8-bit and 32-bit with very satisfying efficiency results. This is a key > >> feature for our embedded users that might also be interesting for SG14. > > > My current aim is to match integer performance for common arithmetic > > operations when using built-ins. This leads to some situations where > > overflow is a big problem - but no worse than dealing with raw integers. > > I'm curious how you deal with multiplying two int-sized values together > > without resorting to wider, slower types.I was under the impression that > > P0106 types always widen to fit their values. > We have resorted to wider integer for internal mul and div or used higher > level algorithms when the compiler switch BOOST_FIXED_POINT_DISABLE_WIDE_INTEGER_MATH > is activated as mentioned above (develop branch only). > In our approach, full multiplication requires: * sign conversion > * left shift for round bit > * multiply n*n --> 2n bits * right shift and round * sign conversion > On a 32-bit system, a full 32*32 -> 64 mul is required. > This full multiplication approach can not achieve your desired efficiency > goal on 8-bit and 32-bitCPUs. Division uses similar approach. > > Multiplication and division with plain int or unsigned can achieve the > efficiency goal --- if it were not for handling rounding and overflow. > > In my current branch, I'm actually trying to get even closer to integer-level efficiency. No longer does 32-bit multiplication result in 64-bit results on systems with 32-bit integer. This means that overflow on 32-bit arithmetic operations is even more common. The solution is explicit casting to 64-bit or use of an integer type which auto-widens: http://johnmcfarlane.github.io/fixed_point/#elastic This is the toughest design issue I face - especially when combined with division. > > >> Thank you and best regards, Chris > > And thank you. Keep up the good work! > > John > Thanks again and best regards, Chris > > Cheers, John

4 7

[serialization]
by alainm 19 Oct '16

19 Oct '16

Hi, I have a few blocking compilation/link problems on the develop branch for which to fixes are pending (46 (3 lines) & 45(1 line)). 45 is a bug in the code I thin, 46 probably works just fine on most platform, but not on mine (recent Intel compiler on CentOS 6.5, which mean advanced features, but old headers). Boths are breaking are breaking some tests on Boost.MPI. Could someone have a look at it ? Regards Alain

1 0

[Serialization] check failed ???
by alainm 17 Oct '16

17 Oct '16

Hi, If I got on: https://github.com/boostorg/serialization/pull/46 I see a message "All checks have failed". If I follow the link "details" I see stuff regarding rake (?) and unfound "rakefiles", What is this all about ? Regards -- Alain Miniussi Pole Génie Logiciel Scientifique Observatoire de la Côte d'Azur Blv de l'Observatoire, Nice

1 0

Read only attributes in C++ (class proposal)
by Daniel Illescas Romero 17 Oct '16

17 Oct '16

Hello, I wanted to make some read only attributes on C++ so I made a class, named ReadOnly. This class will contain an internal private value, only “friend” classes could change this internally. Description: · A read only object will contains an internal value that can’t be changed outside the class. For example: ReadOnly<string> name = “Daniel”; To access its value: object.name, if you try: object.name = “other”, it won’t change it’s value because it’s a read only variable; you can change it’s value only inside the class the object is declared, you could change it like: name.value = “whatever”; · To set a value (outside the class) to a read only attribute you MUST specify a setter function (which can be static and contained inside the class), like: ReadOnly<int> age {ReadOnly::setAge, 1}; (optionally you can also set a default value to the attribute). Example of setter function: static bool setAge(const int& value) { return (value > 0 && value <= 150); } So if you you have an object and you want to change its value like this: object.age = 100; it will change its internal value only if the setter function (which is called internally) returns true. · The idea of doing all of this instead private variables and getters & setters is because this approach is closer to OOP than what is normally used; I mean if you have an object and you want to get an attribute value, what you need to do in most cases is something like: object.getAttribute(), you are calling a function to just take a look at an attribute, that shouldn’t make sense in OOP, that’s why I made all of this. It’s also similar to how you manage getters and setters in Swift, because they are embedded in the attribute and you don’t need to make other functions. :) I uploaded the project to github so everyone can take a look: https://github.com/illescasDaniel/ReadOnly <https://github.com/illescasDaniel/ReadOnly> — I wanted to know your opinion about the idea of the class and also about the implementation, I’d love to upload it to boost libraries but I want to know people opinion and make the class better. Thank you!

2 1

How can I detect if a template static member function exists?
by Vinnie Falco 16 Oct '16

16 Oct '16

I'd like to write a trait: template<class T> struct has_content_length : std::integral_constant<bool, ...>{}; which detects whether or not a template static member function is present in T. Here's a typical T: struct X { template<bool isRequest, class Body, class Headers> static std::uint64_t content_length( message<isRequest, Body, Headers> const& m); }; How can I detect if X::content_length(m) is callable for any m of type message template?

2 1

Re: [boost] [config] Changes to reflect Visual C++ "15" preview 5
by Tom Kent 15 Oct '16

15 Oct '16

I've now added a runner to the test suite with msvc-15.0 (preview 5 installed), it should show up in a couple hours as "teeks99-09o-win2012R2-64on64" (the far right column). The run only took a few minutes instead of an hour or two, so I'm expecting it to look pretty broken. Just glancing at the logs it looks like the compiler isn't even being found. Does this require b2 updates? Tom

2 1

[algorithm] New search algorithms
by Зайцев Александр 14 Oct '16

14 Oct '16

Hello. Now in Boost. Algorithm there are 3 algorithms for searching: Knuth-Morris-Prata, Boyer-Moore, Boyer-Moore-Horspool. They are good algorithms, but there are other efficient algorithms like Turbo-Boyer-Moore, Quick Search, etc. You can find some more here: http://www-igm.univ-mlv.fr/~lecroq/string/index.html Now i am working on new search algorithms for Boost.Algorithm. Maybe are there anybody,who familiar with string search algorithms? -- Best regards, Alexander Zaitsev

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[program_options] -d directory is falling into positional input-files 1_62_0
by Roger Martin 14 Oct '16

14 Oct '16

Hi, Pulled this from a larger application to isolate to the problem: -d ./tmp or -d "./tmp" doesn't go to directory string but is with the positionals: #include <stdlib.h> #include <iostream> #include <exception> #include <string> #include <cstring> #include <memory> #include <fstream> #include "boost/program_options.hpp" int main(int argc, char** argv) { try { boost::program_options::positional_options_description p; p.add("input-file", -1); std::string directory = "./"; boost::program_options::options_description visible("Allowed options"); visible.add_options() ("input-file", boost::program_options::value<std::vector<std::string>>(), "input files can be *.xml, *.pdb, *.mol2, *.mtz, *.cif, *.csv, and *.sdf. Csv and sdf formats are for NMR calculations. csv lists the atoms for which the shifts will be computed. 1st line containts the Header: \"Chain\",\"Residue ID\",\"Sequence\",\"Atom Name\",\"Unbound ppm\",\"Bound ppm\". Then atoms may be listed i.e \"A\",\"MET\",231,\"CE\",10.30,10.50. sdf file contains the ligands for a CSP calculation. ") ("directory,d", boost::program_options::value<std::string>(&directory)->implicit_value("./"), "Directory for publishing output.") ; boost::program_options::options_description all("Allowed options"); all.add(visible);//.add(hidden); boost::program_options::variables_map vm; boost::program_options::store(boost::program_options::command_line_parser(argc, argv).options(all).positional(p).run(), vm); boost::program_options::notify(vm); std::vector<std::string> fileList = vm["input-file"].as < std::vector < std::string >> (); for (unsigned int fileListIndex = 0; fileListIndex < fileList.size(); fileListIndex++) { std::cout<<" "<<fileList[fileListIndex]<<" "<<std::endl; } } catch (std::exception& e) { std::cout << e.what() << std::endl; } return 0; } Built with g++ 4.9.0 on Linux frodo.quantumbioinc.com 2.6.32-573.7.1.el6.centos.plus.x86_64 #1 SMP Wed Sep 23 03:02:55 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux g++ -fPIE -std=c++11 -I${BOOST_HOME}/include -Wl,--allow-multiple-definition -MT main.o -MMD -MP -O3 -c -o main.o main.cpp g++ -pie -Wl,--allow-multiple-definition -o main main.o -L${BOOST_HOME}/lib -lboost_program_options -lc -lm -lpthread -lz -lstdc++ -ldl -lrt And run as ./main 2-aminoethanol.pdb -d ./tmp which results in 2-aminoethanol.pdb ./tmp This code had been working with 1_57_0. Some change in the API I need to adjust for?

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[algorithm] Longest palindromic substring in Boost.Algorithm
by Зайцев Александр 14 Oct '16

14 Oct '16

Hello I want to add to Boost.Algorithm algorithm for finding all palindromes in a sequence in O(N). https://en.wikipedia.org/wiki/Longest_palindromic_substring Is it useful algorithm for Boost? Have you any suggestions? -- Best regards, Alexander Zaitsev

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Re: [boost] [fixed_point] First presentation from GSoC 2015 and more
by John McFarlane 13 Oct '16

13 Oct '16

Hi Christopher. I'm actually the main culprit behind P0037. :) Date: Wed, 12 Oct 2016 18:32:26 +0000 (UTC) > From: Christopher Kormanyos <e_float(a)yahoo.com> > To: "boost(a)lists.boost.org" <boost(a)lists.boost.org> > Subject: Re: [boost] [fixed_point] First presentation from GSoC 2015 > and more > Message-ID: <1026507022.4306136.1476297146580(a)mail.yahoo.com> > Content-Type: text/plain; charset=UTF-8 > > > I'm a bit surprised I didn't see this work before. > > Are you aware that SG14, the gamedev, real-time simulations, embedded > > software and financing study group for the standard > > is working on fixed point real proposal too? > > Here is a version of the proposal:>http://johnmcfarlane > .github.io/fixed_point/papers/p0037r2.html and>http://johnmcfarlane.githu > b.io/fixed_point/papers/p0381r0.html > > I will notify SG14 in case they missed your work too. > Thanks for the information. > We became aware of your work unfortunately very late inthe project. Much > of our fixed_point work stems from myearly prototyping dating from 2011 - > 2013. > I see a lot of similarities in the two bodies of work.Maybe we could > identify the strengths of each work.I don't know if it makes sense to > combine them,but maybe share some concepts or interface ideaswould make > sense. > I discuss P0106R0 (a revision to N3352) in my paper, the latest draft of which is always available here: https://github.com/ johnmcfarlane/fixed_point/blob/master/doc/p0037.md#p0106 I'm honestly not sure which approach is preferable overall. The set of features and qualities requested during SG14 and SG6 meetings is large and conflicting. It includes minimal build times, minimal run-time overhead, every rounding and overflow strategy listed in P0105, decimal radix and support for specialized fixed-point instructions on embedded architectures. > > In your work I've been experiencing some trouble withthe division routine. Can you elaborate? Was this recently? I've been trying out numerous strategies for arithmetic operators. My current preferred approach is to pad the left-hand operand before performing the division but that's only been checked in for a few months. > I also had some problems compilingon VC12 (but you don't target that > compiler anyway).So that's no big deal. > You will need a C++11-compliant compiler as sg14::fixed_point<> creates literal types. Lack of support for features like constexpr constructors is the main obstacle to compiling under VC++ 2013 and earlier. > In your work you are using wrapped versions of elementarytranscendental > functions designed for built-in float.You might appreciate our hand-crafted > functionsdesigned to be highly efficient in several digit ranges. > Yes! I would be very interested in seeing if I could adapt those function. Mine are placeholders and I've deliberately postponed the non-trivial task of adding cmath equivalents. It's come up - maybe a couple of times - whether these functions are desired and the response has been to just keep the proposal narrow so they are not included. There are interesting questions regarding how to implement some functions. For example, you surely don't always want the same inputs and outputs from functions involving angles. And hopefully these functions can be constexpr - unlike existing functions. Also, how have you approached the trade-off between speed and accuracy? I went for a very simple sqrt function which is adequate if the value is calculated at compile time but is likely not desirable at run-time. This isn't a problem that floating-point variants face. > I have also benched our fixed_point on bare-metalembedded systems both > 8-bit and 32-bit with verysatisfying efficiency results. This is a key > featurefor our embedded users that might also be interestingfor SG14. > My current aim is to match integer performance for common arithmetic operations when using built-ins. This leads to some situations where overflow is a big problem - but no worse than dealing with raw integers. I'm curious how you deal with multiplying two int-sized values together without resorting to wider, slower types.I was under the impression that P0106 types always widen to fit their values. > > Thank you and best regards, Chris > > And thank you. Keep up the good work! John > > On Tuesday, October 11, 2016 11:37 PM, Klaim - Jo?l Lamotte < > mjklaim(a)gmail.com> wrote: > > > On 6 October 2016 at 12:07, Paul A. Bristow <pbristow(a)hetp.u-net.com> > wrote: > > > > -----Original Message----- > > > From: Boost [mailto:boost-bounces@lists.boost.org] On Behalf Of > > Christopher Kormanyos > > > Sent: 05 October 2016 23:07 > > > To: boost(a)lists.boost.org > > > Subject: Re: [boost] [fixed_point] First presentation from GSoC 2015 > and > > more > > > > > > >> A partial implementation of fixed-point in a Boost-like > > > >> style based on proposal N3352 is now available. > > > > > > > ... But your links don't work, > > > > Indeed :-( ( > > > > The correct link to the docs for some years used to be > > > > https://dl.dropboxusercontent.com/u/43940943/modular-boost/ > > libs/fixed_point/doc/html/index.html > > > > but sadly this no longer works for reasons that so far escape me (but I > > suspect some change at Dropbox?). > > > > Meanwhile here is a PDF version to whet your appetite until I get a html > > version publicly available. > > > > https://dl.dropboxusercontent.com/u/43940943/modular-boost/ > > libs/fixed_point/doc/fixed_point.pdf > > > > Boost.Fixed_point ? > > =============== > > > > A partial implementation of fixed-point in a Boost-like style based on > > proposal N3352 is now available. > > > > This work is the result of developments from 2013-2016, including efforts > > from GSoC 2015. > > > > The source code is available at: https://github.com/ > > BoostGSoC15/fixed_point > > > > (The master branch will be stable for a while but the develop branch may > > be updated in the light of your feedback). > > > > Preliminary docs are available at: > > > > https://dl.dropboxusercontent.com/u/43940943/modular-boost/ > > libs/fixed_point/index.html > > > > We are potentially interested in submitting this work for inclusion in > > Boost. > > > > We are now requesting comments and suggestions for improvements, > > corrections and any > > further test results if these become available. > > > > Some key library features include: > > > > * proper C++ header-only implementation > > * full numeric_limits and <cmath> functions > > * flexible template choice of split between resolution and range > > * automatic selection of underlying integral representation > > * portability and high efficiency for bare metal microcontrollers > > * interoperation with Boost.Math > > * seamless extension to high-precision using Boost.Multiprecision > > * extensive test suite > > > > Thank you for your consideration. > > Best regards, > > > > Christopher Kormanyos > > > > And apologies from Paul. > > > > > Hi, > > I'm a bit surprised I didn't see this work before. > Are you aware that SG14, the gamedev, real-time simulations, embedded > software and financing study group for the standard > is working on fixed point real proposal too? > Here is a version of the proposal: > http://johnmcfarlane.github.io/fixed_point/papers/p0037r2.html and > http://johnmcfarlane.github.io/fixed_point/papers/p0381r0.html > I will notify SG14 in case they missed your work too. > > Jo?l Lamotte > > _______________________________________________ > Unsubscribe & other changes: http://lists.boost.org/mailman > /listinfo.cgi/boost > > > >

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Re: [boost] : Curiousity question
by Brian Wood 13 Oct '16

13 Oct '16

Edward Diener writes: > I would like to ask a design question for any Boost developers or anyone > on this mailing list who might care to answer. > > You are designing or working on a library, perhaps for Boost, perhaps > for fun, and part of the design of the library has some public > functionality taking a shared pointer as input. You: > > 1) Use boost::shared_ptr > 2) Use std::shared_ptr > 3) Use both boost::shared_ptr and std::shared_ptr with the same > functionality > 4) Use neither, you roll your own shared pointer-like functionality > 5) You don't lke shared pointers and use raw pointers instead > > I really am curious about this. I haven't put any limitation on your > library or made any presumption on who your library is for, on purpose. > Thanks for anyone answering ! I avoid shared pointers. I'll use a unique_ptr if a raw pointer won't work. -- Brian Ebenezer Enterprises - In G-d we trust. http://webEbenezer.net

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[qvm] Doesn qvm contain any sse/avx etc optimizations?
by Viktor Sehr 12 Oct '16

12 Oct '16

If not, is it planned for utilizing it? /Viktor

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Boost library incubator URL address
by Edward Diener 12 Oct '16

12 Oct '16

Is the Boost Library Incubator web site down or removed ? I cannot get to it anymore via a URL. I have this URL, http://www.rrsd.com/software_development/blincubator/index.htm, but it just hangs on me.

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Announcing version 3 of the cxx_dual library
by Edward Diener 11 Oct '16

11 Oct '16

I have created version 3 of the cxx_dual library. version 3 is a large rewrite of the documentation to simplify the use of the library, as well as a change in the directory structure so that the basic usage of the library is through a single header file and the use of a namespace alias, and not through the macro interface. As in: #include <boost/cxx_dual/regex.hpp> void SomeFunction() { cxxd_regex_ns::regex re("A regular expression etc."); bool result(cxxd_regex_ns::regex_match("Some string...",re)); // etc. } What ! No macros ! Actually a few macros still exist for testing which dual library has been chosen and overriding the dual library chosen, but the basic functionality means almost no macros in user code. The library is available at https://github.com/eldiener/cxx_dual.git. What is it ? The Cxx Dual library, or CXXD for short, is a C++ macro header-only library which chooses between using a Boost library or its C++ standard equivalent library for a number of different C++ implementations, while allowing the end-user to use the same code to program either choice. An implementation is a Boost library which has a C++ standard library equivalent whose public interfaces are nearly the same in both cases. An 'implementation' is called a 'mod' for short and each of the possible Boost or C++ standard implementations for that mod are called a 'dual library'. The Cxx Dual library does this by automatically choosing either the Boost library or the C++ standard library for a particular mod, including the correct header file(s) needed for the dual library chosen, and creating a namespace alias for the namespace of the dual library chosen. CXXD also provides a macro-based solution for distinguishing between the Boost version and the C++ standard version of a dual library so that specific code for a particular dual library choice may be written in those cases where the public interfaces diverge.

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Announcing version 3 of the cxx_dual library
by Edward Diener 11 Oct '16

11 Oct '16

I have created version 3 of the cxx_dual library. version 3 is a large rewrite of the documentation to simplify the use of the library, as well as a change in the directory structure so that the basic usage of the library is through a single header file and the use of a namespace alias, and not through the macro interface. As in: #include <boost/cxx_dual/regex.hpp> void SomeFunction() { cxxd_regex_ns::regex re("A regular expression etc."); bool result(cxxd_regex_ns::regex_match("Some string...",re)); // etc. } What ! No macros ! Actually a few macros still exist for testing which dual library has been chosen and overriding the dual library chosen, but the basic functionality means almost no macros in user code. What is it ?

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