September 2019 - Boost - lists.preview.boost.org

CMake Announcement from Boost Steering Committee
by Jon Kalb 13 Aug '24

13 Aug '24

The libraries produced by the Boost community have had a greater impact on the way that the C++ community writes code than any other library implementation. The focus of the Boost community will always be on the libraries, but it is undeniable that we are dependent on and often limited by the infrastructure of our trade. Years ago, the move to Git was contentious; yet, it was required to improve development. In a similar vein our build system has become an impediment for many developers and users, existing and prospective. Therefore, we, the Steering Committee, announce to the Boost community our desire and intent to move Boost’s build system to CMake for users and developers alike. We are soliciting comments and proposals from the community to guide the process and the goals. Our desire is that the community can come to consensus by the end of the calendar year with a vision of supporting users and developers. We understand that the actual process of achieving the end goal will be long, time consuming, and not without its share of conflict. We also recognize that the Boost community is comprised of bright and passionate individuals that are eager to get involved and help get work done. The members of the Steering Committee have been encouraged by the discussions and activity surrounding CMake on the mailing lists over the years and know that many people have voiced visions. We hope that each of you rejoins the discussion to support this initiative and contributes to the common goal of improving Boost’s integration into the broader C++ ecosystem. For the Boost Steering Committee, Jon Kalb, Chair jonkalb(a)boost.org

49 199

[container] static_string ?
by Vinnie Falco 09 Nov '19

09 Nov '19

Beast has static_string which someone has asked to be move, is there any interest in moving this to Boost.Container? See: <https://github.com/boostorg/beast/issues/1691> <https://github.com/boostorg/beast/blob/b7230f12f16fe7a9f7a1ece5be1f607c8552…> -- Regards, Vinnie Follow me on GitHub: https://github.com/vinniefalco

19 50

New JSON library from the maker of Beast!
by Vinnie Falco 23 Oct '19

23 Oct '19

I've been working on a massively-multiplayer online blackjack casino server, called Beast Lounge [1]. The server and client communicate using JSON-RPC over WebSocket. I have developed a brand-new JSON library for this project, in accordance with the following design goals: * Robust support for custom allocators throughout. * Array and object interfaces closely track their corresponding C++20 container equivalents. * Use `std::basic_string` for strings. * Minimize use of templates for reduced compilation times. * Parsers and serializers work incrementally (['online algorithms]). * Elements in objects may also be iterated in insertion order. You can see the JSON library in development here: https://github.com/vinniefalco/json Is there any interest in proposing this for Boost? I'm happy to hear feedback or answer questions about this library. Feel free to open an issue on the repository, or reply here. Thanks [1] <https://github.com/vinniefalco/BeastLounge>

21 68

A solution to return dynamic strings without heap allocation. Any interest?
by Roberto Hinz 09 Oct '19

09 Oct '19

Hi all, I haven't been succesful at attracting interest in a formatting library [1] I've been working lately. But recently I realized that part of it could be isolated as a small standalone library that could solve an old common troublesome situation in C++: Suppose you need to create a function that returns/provides a string whose content and size is unknown at compilation time. The first approach is to make it return a `std::string`. But if it need to be usable in environments like bare-metal real-time system, then one usually makes it take a raw string as an output argument, more or less like this: struct result{ char* it; bool truncated; }; result get_message(char* dest, std::size_t dest_len); But this is clearly not a perfect solution since there's nothing really effective the caller can do when get_mesage fails because of the destination string being is too small. So I present the `outbut` abstract class. It somehow resembles `std::streambuf`, but with a simpler and lower level design, which is the result of many attempts looking for the best performance [2] and usability in my formatting library. Afaics, it does not require a hosted C++ implementation, though I would like someone else to confirm that. Now the caller of `get_message` has to choose or create a suitable class type deriving from outbuf, that dictates where the message is written to. For example, if the user wants to get a `std::string`, then `string_maker` will do the job: #include <boost/outbuf/string.hpp> // ... boost::outbuf::string_maker<false> msg; get_message(msg) std::string str = msg.finish(); Or, if one wants it to write into a raw string, then use `cstr_writer` char buff[buff_size]; boost::outbuf::cstr_writer csw(buff, buff_size); get_message(csw); auto result = csw.finish(); if (result.truncated) { // ... Those `finish` functions above do not belong to `outbuf`. They are defined in the concrete derived types only. It's solely by convention that they share the same name. Yes, using `string_maker` still leads to heap allocation and `cstr_writer` to string truncation. The problem isn't solved by these. However, a string object is never the final destination. So the user could rather use another class that writes the message directly into the final destination ( output console, a log file, an LCD display or whatever ). It is not difficult to implement concrete subtypes of `outbuf`. `outbuf` is actually a type alias: template <bool NoExcept, typename CharT> class basic_outbuf; using outbuf = basic_outbuf<false, char>; using outbuf_noexcept = basic_outbuf<true, char>; That `NoExcept` template parameter is perhaps the controversial part. It is not present originally in my formatting library. Besides the destructor, `basic_outbuf` has only one virtual function: `recycle()`, and it is declared as `noexcept(NoExcept)`. This is the only effect the `NoExcept` template parameter has. All other functions are guaranteed not to throw. Hence, by taking a `outbuf_noexcept&` parameter, a function states that the destination must not throw. That might be particularly good if such object comes from another module and we must avoid exceptions crossing modules boundaries. On the other hand, if a function takes an `outbuf&`, then it also accepts `outbuf_noexcept&`, because `basic_outbuf<true, CharT>&` derives from `basic_outbuf<false, CharT>`. When using `string_maker` you can choose between the two kinds. `string_maker<true>` derives from `basic_outbuf<true, char>&`. So if any exception raises from its internal `std::string`, then it is caught by a try/catch(...) block, stored as an `exception_ptr` and rethrown by `finish()`. This has the undesirable effect of delaying its proper handling ( after all, we rather stop what's being doing as soon as possible when an error appears ). So I think the recommendation would be to use `string_maker<false>&` if possible, and `string_maker<true>&` only if necessary. The reason why I think it's controversial is that it makes `recycle()` violates the Lakos Rule. And although the Lakos Rule is not a requirement in boost (afaik), I was wondering whether this library could interest LEWG in future as well. Anyway, this whole noexcept idea is not a central part of this library and can it be removed. Now, the other topic is how to implement that `get_message` function, i.e., how to write into an `outbuf` object. One can use `puts` and `putc` functions to insert string and chars. One can also use `fmtlib` through an output iterator adapter. Or one can write directly in the buffer. But I will ask you to read the doc [3] for that. It's a quick read, quicker than this email. The repository is: https://github.com/robhz786/outbuf I would prefer it to be part of Boost.Core instead of being a standalone library, and also to remove the `outbuf` namespace. But that is up to you. Best regards, Roberto [1] The Stringify library: https://github.com/robhz786/stringify [2] The great performance of Stringify is mainly thanks to the design of outbuf ( named there as `output_buffer` ): https://robhz786.github.io/stringify/doc/html/benchmarks/benchmarks.html#be… [3] "Writing into and outbuf object" https://robhz786.github.io/outbuf/doc/html/index.html#boost_outbuf.overview…

5 13

[Boost.MSM] Please, update master with changes from develop
by Deniz Bahadir 08 Oct '19

08 Oct '19

Hello world, I just stumbled across a compilation-error with the latest Boost release (1.71) of Boost.MSM for which I already provided a merge-request [1] a year ago, and which was merged to "develop" branch at that time, too. Still, the "master" branch lags this merge-request (and a lot more [2] from former years which are in "develop") but has some other unrelated merge-requests [3] merged in which are not in "develop". I would love seeing "develop" being merged into "master" (and maybe vise-versa) so that bugs for which fixes already exist will no longer be present in the next Boost release. Thanks for taking care of. Deniz [1] https://github.com/boostorg/msm/pull/15 [2] https://github.com/boostorg/msm/compare/master...develop [3] https://github.com/boostorg/msm/compare/develop...master

3 2

Re: [boost] New JSON library from the maker of Beast!
by Bjorn Reese 30 Sep '19

30 Sep '19

On 9/30/19 12:14 PM, julien.blanc(a)tgcm.eu wrote: > Do you have an example of an efficient implementation of a pull parser on top of async io ? I find push parsers really more straightforward in that case. Vinicius has an HTTP pull parser here: https://github.com/BoostGSoC14/boost.http > Pull parsers can also be built on top of push parsers, although it is less easy. Indeed, that is how we implemented XmlTextReader in libxml2, and it was a rather painful experience. Coroutines can help, as Phil pointed out, but pull parser are also a natural fit for parser combinators (e.g. HTTP contains a partial URL syntax, so it could be created combining HTTP and URL pull parsers.) I am not sure how well coroutines would handle this case.

1 0

Who is maintaining Boost.Random?
by Christoph Conrads 29 Sep '19

29 Sep '19

Last Tuesday I submitted a feature request for Boost.Random and received absolutely no feedback which seems to be unusual judging by last week's discussions (e.g. secure-by-default networking with Boost.Asio). Is anybody maintaining Boost.Random currently and if not, how can I proceed with my feature request? Christoph Conrads

2 3

How to handle contributions from anonymous?
by Hans Dembinski 27 Sep '19

27 Sep '19

Hi all, I got a PR from a contributor who prefers to remain anonymous. The person created new files and instead of putting a real name, the person added just initials. I am talking to the person to see whether they can be convinced to give a real name. Any advice on how to handle this? My feeling is that a copyright notice without a real name is illegal. I could publish the code in my name, but then a documented transfer of copyright from the contributor to me is missing, which then puts me in a vulnerable position. Any thoughts? Best regards, Hans

5 6

MS STL now open source (and using Boost)
by John Maddock 26 Sep '19

26 Sep '19

Microsoft's standard library is now in the process of going open source (the code is there, but not the tests yet), see : https://devblogs.microsoft.com/cppblog/open-sourcing-msvcs-stl/ Interestingly they're using the Math library's special functions en-mass for enhanced <cmath> support, and a quick grep of the code turns up other references to Boost, though I haven't identified the libraries they've borrowed from yet. Hopefully this means that in the long turn we'll see patches and enhancements flowing in both directions for the benefit of all. John. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

11 14

more (hyper)complex types
by Gero Peterhoff 26 Sep '19

26 Sep '19

Hallo Developers, Hello John, I'm missing the (hyper)complex types in boost::math: - dual, i²=0 https://en.wikipedia.org/wiki/Dual_number - acomplex (anormal complex), i²=1 https://en.wikipedia.org/wiki/Split-complex_number - sedenion, https://en.wikipedia.org/wiki/Sedenion and the arithmetic functions for this types. Can you provide it? That would be great! thx Gero

3 2

Memory leak in add_options
by Vinitha Anish(UST,IN) 24 Sep '19

24 Sep '19

Hi , Our static analyzer report an memory leak with add_options . We use namespace po = boost::program_options; po::options_description desc("Options"); desc.add_options() ("name", po::value<std::string>(), ...) // add option ; The issue reported in boost library file value_semantic.hpp:199 template<class T> typed_value<T>* value(T* v) { typed_value<T>* r = new typed_value<T>(v); return r; } memory is dynamically allocated here and return at line 201. Can anyone suggest how do we handle this memory leak.

1 0

How to bind boost::asio::ip::tcp::socket to a local endpoint with a sperific local IP address?
by JH 24 Sep '19

24 Sep '19

Hi, I have searched the documents, but still could not clarify how to bind the socket to a local IP address, which API could I add my local IP address to it? socket.bind(boost::asio::ip::tcp::endpoint(boost::asio::ip::tcp::v4(), 12345)); ....... boost::asio::ip::tcp::resolver::query query(remoteServerIPAddress, portNumber); Thank you. Kind regards, - jh

3 3

Source code of boost-commitbot git user
by LE GARREC Vincent 24 Sep '19

24 Sep '19

Hi, I work on a company where the architecture of the software is closed to boost : one super project and lots of submodules. We are spending lots of time with the superproject by doing "fetch/merge/checkout" every time because someone else updated a submodule just 15 minutes ago. In boost, it looks like the superproject is updated by Travis (or maybe a git post hook ?). Does this script is available somewhere? It will really help us and improved your time. I took a look but I didn't find anywhere the source code. Thanks for your help, Best regard, Vincent

1 0

clang-9 on travis?
by John Maddock 23 Sep '19

23 Sep '19

Has anyone figured out how to install clang-9 on travis? I'm seeing: Adding APT Sources Disallowing sources: llvm-toolchain-xenial-9 See https://travis-ci.org/boostorg/multiprecision/jobs/588146074 With .travis.yml containing: - os: linux env: TOOLSET=clang COMPILER=clang++-9 CXXSTD=c++17 TEST_SUITE=misc addons: apt: packages: - clang-9 - libgmp-dev - libmpfr-dev - libmpc-dev - libmpfi-dev sources: - ubuntu-toolchain-r-test - llvm-toolchain-xenial-9 Which works fine for clang-8. Any ideas anyone? Thanks! John. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

2 2

Call for Papers - ICITST-2019 - London, UK
by Galina Akmayeva, ICITST 20 Sep '19

20 Sep '19

CALL FOR PAPERS! ************************************************************ The 14th International Conference for Internet Technology and Secured Transactions (ICITST-2019) Venue: CCT Venues-Docklands London, UK December 9-11, 2019 www.icitst.org ************************************************************ The ICITST is an international refereed conference dedicated to the advancement of the theory and practical implementation of secured Internet transactions and to fostering discussions on information technology evolution. The ICITST aims to provide a highly professional and comparative academic research forum that promotes collaborative excellence between academia and industry. The ICITST-2019 invites research papers that encompass conceptual analysis, design implementation and performance evaluation. The topics in ICITST-2019 include but are not confined to the following areas: Internet Applications and Technology: * Internet Architecture * Internet of things * Broadband Access Technologies * Application Agents * Boundary Issues of Internet Security * Database Management * Data Models for Production Systems and Services * Artificial Intelligence and Expert Systems * IPSec Quality of Service * Knowledge Management * Embedded Systems * Defence Systems Ubi/Cloud Computing: * Authentication and Access Control for Data Protection in Ubi/Cloud Computing * Context-Awareness and its Data Mining for UbiCom * Data Grids * Distributed Information Systems * Human-Computer Interface and Interaction for UbiCom * Ubiquitous Systems * USN/RFID Service * Smart Homes and its Business Model for UbiCom Service * Security and its Data Management for UbiCom * Peer to Peer Data Management * New Novel Mechanism and Application for Ubi/Cloud Computing Information Security: * Trust, Privacy and Data Security * Network Security Issues and Protocols * Security Challenges and Content Authoring * Cryptography * Secure Communications * Authentication Techniques * Chaos-based Data Security * MANET Security * Wireless Sensor Network Security * Organization Considerations in Security Policy Formulation and Implementations * Digital Forensics and Crimes * Biometrics * Cyber Security Multimedia and Web Services: * Intelligent Multimedia and its Data Management * Multimedia Information Systems * Multimedia Security * Web Databases * Web Metrics and its Applications * Web Mining including Web Intelligence and Web 3.0. * Web Services * XML and other extensible languages * Semantic Web and Ontology Bitcoin *Challenges and its Roadmap *Crypto-Assets *Current State of Privacy in Bitcoin *Decentralised Technology *Data Licensing *Digital Currencies *Fintechs *Future Payment Implications *Standardisation-Related Issues *Technical, Business and Regulatory Aspects *Technology-based Risks Infonomics and e-Technology: * Infonomics * Information Visualization * Information Management * Information Quality * Technology-Enabled Information * e-Learning * e-Commerce * e-Business * e-Government * e-Society * System Design and Security for e-Services * Synchronizing e-Security Submissions: *You can submit your abstract via email at abstract(a)icitst.org *You can submit your extended abstract or paper online at http://icitst.org/paper-submission/ or email it to extendedabstract(a)icitst.org or papers(a)icitst.org *You can submit your poster via email at posters(a)icitst.org *You can submit your workshop or tutorial proposal via email at workshop-tutorial(a)icitst.org *You can submit your speaker's proposal online at https://icitst.org/call-for-speakers/ or via email at speakers(a)icitst.org Submission Dates: *Abstract and Extended Abstract Submission Date: September 20, 2019 *Notification of Abstract and Extended Abstract Acceptance/Rejection: September 25, 2019 *Proposal for Industrial Presentation: September 20, 2019 *Notification of Industrial Presentation Acceptance: September 25, 2019 *Full Paper Submission Date: September 27, 2019 *Notification of Paper Acceptance/Rejection: October 10, 2019 *Workshops and Tutorials Submission Date: September 20, 2019 *Notification of Workshop and Tutorial Acceptance: September 25, 2019 *Special Track Submission Date: September 20, 2019 *Notification of Special Track Acceptance: September 25, 2019 *Poster/Demo Submission Date: September 20, 2019 *Notification of Poster/Demo Acceptance: September 25, 2019 *Camera Ready Paper Due: November 15, 2019 *Early Registration Deadline: October 25, 2019 *Late Registration Deadline: November 25, 2019 *Conference Dates: December 9-11, 2019 For more details, please contact [1]info(a)icitst.org References 1. mailto:info@icitst.org

1 0

[multiprecision] how to catch both underflow and overflow
by blacksmith＠peerfreedom.org 20 Sep '19

20 Sep '19

Hello, when using boost multiprecision [1] to execute even simple math operations like addition x = x+1 or x-1 it seems on mathematical error it might throw either std::range_error or std::overflow_error or std::underflow_error . Sadly it seems that it's not the case that overflow and underflow are child classes of range_error. So, in more complex math expression to detect any math error you must write catch(....) for all 3 of them (because just catching common std::runtime_error would be too broad and might hide some unrelated error). Is there some better way for this? Perhaps boost should introduce a common type for math error and throw own under/over/range errors that inherit from std's one (for compatibility) and also inherit from boost::math_range_error to allow catch (boost::math_range_error) // either over/under flow or other math [1] for example using type like: boost::multiprecision::number< boost::multiprecision::cpp_int_backend< 64-1, 64-1, boost::multiprecision::signed_magnitude, boost::multiprecision::checked, void> > -- GPG: 31A8 55AA 07BE 5145 65EB 2292 65A6 1F7A 9781 DF89

3 2

Requesting endorsements of Boost.STLInterfaces for review
by Zach Laine 20 Sep '19

20 Sep '19

As mentioned a couple of weeks ago, I started a small library that was an updated iterator_facade. It is now a still-smallish library called stl_interfaces that includes a pre-C++20 implementation of view_interface, and analogous templates iterator_interface (a cross between Boost.Iterator's iterator_facade and iterator_adaptor), and container_interface. Each of these makes it easier to write a view, iterator, or container, respectively. Using container_interface, I was able to write a version of static_vector in which I implemented only 21 member functions, and the template provided the other 40(!) functions. The library is C++14 and later. There is an inline v1 namespace for the C++14 implementations, and an experimental non-inline v2 namespace with implementations using C++20 standard concepts. The part using C++20 concepts requires GCC 8 or 9, and cmcstl2 (more info on that on the Github page). Github page: https://github.com/tzlaine/stl_interfaces Online docs: https://tzlaine.github.io/stl_inteTherfaces/doc/html/index.html <https://tzlaine.github.io/stl_interfaces/doc/html/index.html> Oh, and if you're willing to act as review manager, please let me know. Zach

9 17

[GitHub] Checks not listed for Travis CI
by Mateusz Loskot 18 Sep '19

18 Sep '19

Hi, GitHub offers the Checks tab [1] which displays CI checks based on Travis CI, Azure Pipelines, etc. I can't find out why the Travis CI ones are not displayed for any of repositories under github.com/boostorg/ I checked Histogram, Beast, and a few others and ffor GIL only Azure Pipelines is displayed (I integrated AzP there from the marketplace fairly recently). I suspect, that is due to the fact Travis CI integration was installed long time ago, using an old way, so it does not 'recognise' new features. For example, using the old webhooks/services method now deprecated which then was automatically ported to new marketplace-based integrations. Does anyone know how to add the Checks feature to boostorg/ repos? One of interesting feature of it is that it can display "a specific line in a commit causes a check to fail" [1] [1] https://help.github.com/en/articles/about-status-checks#checks Here is example of the Checks in full: https://github.com/OSGeo/gdal/pull/1776/checks I can confirm enabling the Checks has nothing to do with the branch protection feature and enabling required statuses of PRs. Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

2 2

Details of environment building release docs and website
by Mateusz Loskot 18 Sep '19

18 Sep '19

Hi, Where can I find details about the environment used to build the website and the documentation for the releases? For example, - What is the OS? (i.e. system packages can be identified then) - What is toolset and compiler version used? GCC 4.8? - What is the version of Python, Doxygen, AsciiDoc, Sphinx? I looked at these places, but it's still unclear to me https://www.boost.org/development/website_updating.html https://github.com/boostorg/website/blob/master/.travis.yml Or was I supposed to derive the answer from the Travis CI's image php:'5.3'? Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

1 0

[Quickbook] VSCode Extension for syntax colouring & simple preview
by Jan Bouwer 18 Sep '19

18 Sep '19

I've built a Visual Studio Code <https://code.visualstudio.com/> extension to provide simple syntax colouring & preview generation for Boost.Quickbook source files. It is available from within the VSCode extension marketplace or at https://marketplace.visualstudio.com/items?itemName=JBouwer.boost-quickbook… - from where the GitHub repos/issue tracker can be accessed too. Perhaps somebody else may find this useful too - like I have. Regards Jan Bouwer

2 1

[program_options] Proposal: self-contained, header-only port of Boost Program Options library
by Vicram Rajagopalan 17 Sep '19

17 Sep '19

I am interested in creating a header-only implementation of the Boost Program Options library that only depends on the C++ standard library. Program Options uses several other Boost libraries, so I would have to re-implement some of it using standard library constructs. I have 2 questions for the community: 1. Would you use something like this if it were available? 2. Do you know of any implementation details of Program Options which might make some part of this difficult or impossible? To be clear, I do not intend for this to be merged into Boost in any form. Rationale: There is no portable command-line argument-parsing capability in the C++ standard library. There's getopt, but that's in unistd.h which is only available on Unix-based systems. The only widely-used C++ command-line parsing library I am aware of is Program Options, but that requires adding a dependency on Boost to your project, which seems like overkill to me. I would like to be able to simply add a project as a submodule in my Git repo and #include it without even having to add anything to my build files. The goal is to ensure that the library is as portable and easy to include as possible, because it shouldn't be difficult to parse command-line options. I appreciate any thoughts, comments, or criticisms! -Vicram Rajagopalan

9 14

[Boost.numeric.ublas] Compiler warnings when building with O2 optimizations and NDEBUG defined
by Albert Perlman 17 Sep '19

17 Sep '19

I am using boost v1.69, compiling with g++-7 for an x86 target. If I build with -O2 optimization flags when NDEBUG is defined, I get the following compiler warning: ./../boost/numeric/ublas/matrix_expression.hpp:59:20: error: ‘*((void*)&<anonymous> +8)’ is used uninitialized in this function [-Werror=uninitialized] return e_.size2 (); If I add -fno-partial-inling to the compiler flags, this makes the warning go away. This warning does not appear if NDEBUG is not defined, regardless of optimization flags. This behavior is the same with boost v1.71. I would like to build with the -fpartial-inling optimization when NDEBUG is defined. Is there a workaround to fix this warning? -- Albert -- IMPORTANT: The information contained in this transmission may be privileged, proprietary and confidential and protected from disclosure. It is intended only for the intended recipient. If you are not the intended recipient or a person responsible for delivering this transmission to the intended recipient, you may not disclose, copy or distribute this transmission or take any action in reliance on it. If you received this transmission in error, please notify us immediately by replying to this message and please dispose of and delete this transmission. Thank you. Yaskawa America, Inc.

1 0

Write data to NAND flash file system
by JH 13 Sep '19

13 Sep '19

Hi, I am using boost::filesystem to write / remove files to NAND flash file system where it writes by pages, the system can cache and pack data upon write back to avoid segmentation if fsync(), fdatasync(), O_SYNC or a sync mounted filesystem are not used to force write. Will the boost::filesystem::ofstream and operator<< involve any of sync call? Which IO library is not using sync call? Thank you. Kind regards, - jupiter

1 0

math
by Gero Peterhoff 12 Sep '19

12 Sep '19

Hello Developers, Hello John, thanks for making the float128_t features I missed available in boost 1.71. But: - I miss in boost::math::constants log2_e (M_LOG2E); You have written in the documentation that all constants are now available; are there any other constants missing? - in boost/multiprecision/float128.hpp, the value in numeric_limits<float128_t>::is_bounded must be true Thanks and Greetings Gero

2 1

Secure-by-default networking
by Alex Christensen 11 Sep '19

11 Sep '19

At https://github.com/boostorg/asio/pull/283 <https://github.com/boostorg/asio/pull/283> I’ve attached a proof-of-concept which explores making ASIO secure by default. The C++ committee is discussing what secure-by-default networking would look like in the soon to be published papers P1860 and P1861. Since the C++ Networking TS is based on ASIO, this seems like a good place to try things out. The implementation uses BoringSSL for its crypto and Security.framework to evaluate certificates against the root certificates trusted by the system. I've implemented enough to see what the API shape would need to be, and it works with basic client and server programs. I’d love to get your feedback on this initial work, including any implementation concerns you have and suggestions on portability. I don’t think the patch is ready to commit as-is.

3 2

Re: [boost] Secure-by-default networking
by Bjorn Reese 11 Sep '19

11 Sep '19

On 9/11/19 1:35 AM, Alex Christensen via Boost wrote: > At https://github.com/boostorg/asio/pull/283 <https://github.com/boostorg/asio/pull/283> I’ve attached a proof-of-concept which explores making ASIO secure by default. The C++ committee is discussing what secure-by-default networking would look like in the soon to be published papers P1860 and P1861. Since the C++ Networking TS is based on ASIO, this seems like a good place to try things out. Please don't. There are plenty of networking applications that do not use SSL. Use ssl::stream if you want secure-by-default.

1 0

Re: [boost] Requesting opinions on CECS (C/C++ Error Control) library for possible boost implementation.
by Bjorn Reese 11 Sep '19

11 Sep '19

On 9/8/19 3:17 PM, Terablade via Boost wrote: > I have also released the library on github:https://github.com/terablade2001/CECS This library is described as handling "textual informative error control" using severity levels, so the first question that comes to mind is how this differs from Boost.Log? PS: The standard as reserved all symbol names starting with an underscore followed by a capital letter.

2 1

[Random] Proposal: Faster RANLUX engines
by Christoph Conrads 10 Sep '19

10 Sep '19

Boost.Random and the C++11 standard library ship with a 24- and a 48-bit RANLUX pseudo-random number generator (PRNG). I propose to add 32- and 64-bit RANLUX PRNGs because they are at least 40% faster. Additionally, the 32-bit RANLUX PRNG can be implemented as follows: #include <boost/cstdint.hpp> #include <boost/random.hpp> namespace br = boost::random; typedef br::subtract_with_carry_engine<boost::uint32_t,32,3,17> ranlux32_base; typedef br::discard_block_engine<ranlux32_base, 389, 16> ranlux32; There is C++98 benchmark code at the end of this e-mail requiring only Boost and a C++ compiler. Below I will briefly discuss the theory behind RANLUX PRNGs, where the new generators are coming from, and why the 64-bit RANLUX PRNG requires (a few lines of) new code. Drawing from RANLUX PRNGs is a two-step process. In the first step a value is drawn from a "subtract-with-borrow" (SWB) generator implementing b-bit modular arithmetic [1]. Then, values are generously discarded yielding uniformly distributed values (uniform in a dynamical systems model) [2]. The RANLUX PRNGs using 24- and 48-bit arithmetic always gave me an itch so I looked into the motivation behind this. It turns out [3] that this restriction arose likely from a) computational limitations in the 1990s and b) Lüscher's interest in the generation of floating-point numbers (single-precision floating-point numbers have 24-bit significand). SWB PRNGs come in two flavors (Type I, Type II) and they make use of three parameters called base b, short lag s, and long lag r. Using modern prime factorization methods, one can quickly come up with the 32-bit PRNG above, a Type I SWB generator with b=2^32, r=17, and s=3. This one can be implemented as shown above. To generate 64-bit values, one should use a Type II SWB with b=2^64, r=62, and s=5 (all other 64-bit generators with b=2^64 and r < 100 will be awfully slow). What distinguishes the different types of SWBs is the recurrence for the computation of variates. For Type I it is x_n := (x_{n-s} - x_{n-r} + c_n) mod b, where c_n is a carry bit. For Type II it is x_n := (x_{n-r} - x_{n-s} + c_n) mod b. (Observe the order of long lang and short lag in these formulas.) Type II SWBs are not difficult to implement but it requires either a modification of `subtract_with_carry_engine` or a new class. Let me know what you think about this proposal. Christoph Conrads [1] G. Marsaglia, A. Zaman: "A New Class of Random Number Generators". 1991. URL: https://www.jstor.org/stable/2959748 [2] Martin Lüscher: "A Portable High-Quality Random Number Generator for Lattice Field Theory Simulations". 1994. URL: https://arxiv.org/abs/hep-lat/9309020 [3] Christoph Conrads: "Faster RANLUX Pseudo-Random Number Generators". 2019. URL: https://christoph-conrads.name/faster-ranlux-pseudo-random-number-generators // Build with: // c++ -Wextra -Wall -std=c++98 -pedantic benchmark.cpp -O3 \ // -march=native -DNDEBUG -lboost_chrono -lboost_system #include <boost/chrono.hpp> #include <boost/cstdint.hpp> #include <boost/random.hpp> #include <cassert> #include <cstdio> #include <limits> #include <string> namespace chrono = boost::chrono; typedef chrono::milliseconds milliseconds; typedef chrono::process_cpu_clock my_clock; namespace br = boost::random; typedef br::subtract_with_carry_engine<boost::uint32_t,32,3,17> ranlux32_base; typedef br::discard_block_engine<ranlux32_base, 389, 16> ranlux32; struct dummy_engine { typedef boost::uint32_t result_type; static result_type max() { return std::numeric_limits<result_type>::max(); } static result_type min() { return std::numeric_limits<result_type>::min(); } result_type operator() (); result_type state_; }; dummy_engine::result_type dummy_engine::operator() () { return state_++; } std::string get_name(const dummy_engine&) { return "dummy-prng"; } std::string get_name(const br::ranlux24&) { return "ranlux24"; } std::string get_name(const br::ranlux48&) { return "ranlux48"; } std::string get_name(const ranlux32&) { return "ranlux32";} template<typename Generator> typename Generator::result_type draw(Generator& gen) __attribute__((noinline)); template<typename Generator> typename Generator::result_type draw(Generator& gen) { return gen(); } template<typename Generator> void run(boost::uintmax_t num_draws) { assert(Generator::min() == 0); unsigned w = Generator::max() == std::numeric_limits<boost::uint64_t>::max()?8u: Generator::max() == (UINTMAX_C(1)<<48) - 1u ?6u: Generator::max() == std::numeric_limits<boost::uint32_t>::max()?4u: Generator::max() == (UINTMAX_C(1)<<24) - 1u ?3u: Generator::max() == std::numeric_limits<boost::uint16_t>::max()?2u: Generator::max() == std::numeric_limits<boost::uint8_t>::max() ?1u: 0u ; Generator gen; my_clock::time_point t_0 = my_clock::now(); for(uintmax_t i = 0; i < num_draws; ++i) draw(gen); my_clock::time_point t_1 = my_clock::now(); milliseconds t_ms = chrono::duration_cast<milliseconds>(t_1 - t_0); double bytes_per_sec = w * num_draws * 1000u/double(t_ms.count()); std::string name = get_name(gen); boost::uint16_t dummy = boost::uint16_t(gen()); std::printf( "%-26s | %10lu | %20.2e | %hu\n", name.c_str(), t_ms.count(), bytes_per_sec, dummy ); } int main() { boost::uintmax_t num_draws = UINTMAX_C(100000000); run<dummy_engine>(num_draws); run<br::ranlux24>(num_draws); run<ranlux32>(num_draws); run<br::ranlux48>(num_draws); }

1 0

Interest in circular span?
by Bjorn Reese 10 Sep '19

10 Sep '19

I am working on a circular queue library that contains a non-owning circular span, a fixed-sized circular array, and a dynamically resizable circular vector. Would you be interested in adding such a library to Boost? The design is inspired by Boost.CircularBuffer, std::span, and P0059R4 std::experimental::ring_span. The code can be found at: https://github.com/breese/trial.circular The documentation can be found at: https://github.com/breese/trial.circular/tree/develop/doc circular::span can be used to implement the P0059R4 ring_span, as shown in one of the example: https://github.com/breese/trial.circular/blob/develop/example/p0059/ring_sp… circular::span can also be used to implement most parts of boost::circular_buffer; all except insertions and erasure at arbitrary positions.

7 10

[Intrusive] Movable intrusive container elements?
by Phil Endecott 09 Sep '19

09 Sep '19

Dear Experts, Is it possible to make intrusive container elements movable? Here's the scenario. Say I have struct Thing { int id, string name }; and I want a container of those indexed by both the id and the name. Using Boost.Intrusive I can add two hooks to the struct and have two intrusive::sets, one using id as the key and the other using name. All good. But say my ids are a contiguous range of integers starting at zero. It would be much better to store the Things in a vector (or similar), indexed by the id, and use Intrusive only for the name index. Or if my ids are not contiguous, I might still prefer to keep the things in a vector sorted by id and do id lookup by binary search (i.e. a flat_set). In both cases, the issue is that when the vector expands or is sorted the elements are moved, and this will invalidate the pointers used for the name index. Is is possible to fix this using move constructors and move assignment for the hooks? I.e. those operations could adjust the pointers pointing to the element's old location to point to its new location. (This has some similarities to how auto-unlink hooks already fix pointers to remove the being-deleted item.) Maybe there is some complication that makes this impossible. Or maybe this is already possible?? Any thoughts anyone? Regards, Phil.

2 2

Requesting opinions on CECS (C/C++ Error Control) library for possible boost implementation.
by Terablade 08 Sep '19

08 Sep '19

Hi all. Recently I focused on completing and releasing a public a C/C++ library for C/C++ Error Control System. I've exposed the library to public via two articles in Linked In, and especially in the "C++ Developers Groups" were I got some positive feedback (a few comments and likes). A "Senior Architect at Apple" left the following comment: "Man that’s error traceability for a lot of readability". This made me wonder if this library deserves to be exposed more to C/C++ developers, and led me to think of boost library. Personally I'm testing the library by integrating it in different projects, and I'm quite happy from the outcome. With very few code (increased readability) and a specific design approach for capturing and handling possible errors, it does provide a lot of customized error traceability - a feature which for me is quite important on complex projects and especially when multiple libraries mix up and need integrated error tracking through all of them. Reading the boost guidelines I joined this mailing list to request review and opinions.As my free time is a a bit limited to convert and test the library to be supported by boost, I'd like some comments and review first.Do you believe that CECS could be a useful util for Boost? Should I go for it? The two articles in that group (requires membership) is at:https://www.linkedin.com/feed/update/urn:li:activity:6568218380594098176… articles are also in my profile:https://www.linkedin.com/pulse/cecs-cc-error-control-system-vasilei… I have also released the library on github:https://github.com/terablade2001/CECS I'd like to note that the library has been favored till now by 7 accounts in github (8 including me) which, for me, is also a positive feedback. Thanks for your time,V. Pothos

1 0

[GSOC19] Congrats to all students and mentors
by Damian Vicino 06 Sep '19

06 Sep '19

Hi, GSOC finished for 2019. We had 11 students this year and all of them survived the summer and contributed a lot of good stuff. Hopefully, most of it will be merged in the next few weeks. Thanks to all students and mentors, and to Boost community for supporting the program. Special thanks to David Bellot that worked as org admin and dealed with the logistics in addition to mentor. Cheers, Damian

2 1

[bimap] Maintaining library
by Edward Diener 04 Sep '19

04 Sep '19

Could someone please take a look at bimap in order to maintain the library. I have had a simple PR since last December, simply to remove executable permissions from some files, which has been ignored and no one appears to be maintaining the library.

1 0

boost::asio::deadline_timer and boost::asio::io_service
by JH 02 Sep '19

02 Sep '19

Hi, I use a single thread to run 3 classes using boost::asio::deadline_timer, the timers are managed by boost::asio::io_service. I deliberately use a single thread to avoid mutex, I believe those 3 timers are called exclusively by boost::asio::io_service in a single thread, there won't be race condition to share the objects among them, is it correct? Thank you. Kind regards, - jupiter

2 7

Re: [boost] A solution to return dynamic strings without heap allocation. Any interest?
by Bjorn Reese 01 Sep '19

01 Sep '19

On 8/29/19 3:24 PM, Roberto Hinz via Boost wrote: > auto result = csw.finish(); > if (result.truncated) { > // ... I suggest that you change the return type of finish() to contain the number of element written instead of the truncated boolean. This would make outbuf extensible to binary data as well where you cannot rely on a terminating zero to tell you how much data has been written. The return type could also have begin()/end() member functions, which makes it directly usable with STL algorithms. In that case it would also make sense to have data()/size().

2 3