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[Promotional] ghournal - a commandline based blog engine for gh-pages
by Ganesh Prasad 05 May '16

05 May '16

***DISCLAIMER*** *This is a self promotional message and quite unrelated to Boost and C++. But I believe, it's something that makes lives of developers easier, in fact I built it to make my life easier. Now, as an OpenSource activity it needs some promotion to attract users and contributors alike. * *Also, I am not good at writing promotional messages, so this mail might look really messy. Hence, apologies in advance.* *********************************************************************************************** git is the lifeline of most of the OpenSource activities around the globe. We all write code, create projects on github and push our changes to the repo and blah blah blah... That's what we all do, git add | commit | merge | push are probably the most used commands on a developer's console, the command pattern is muscle memory. Now with the introduction of github-pages it has been possible to host static websites for your projects on github, most of the serious projects on github already have their static websites there. Sometimes we want to maintain blogs for our projects on the project website. But github-pages being a static platform does not provide backend scripting or database capabilities. So, conventional blogging (like on blogger/wordpress) is not natively possible on github-pages. Sometimes we wish that blogging was possible and conveniently easy to use on github-pages. Also, some of us (like me for instance) sometimes think like, "life would have been easier if blogging was as simple as git init..git commit...git push, maybe something like blog init... blog new... blog publish". *ghournal <https://www.npmjs.com/package/ghournal>* as a tool designed for users of git, makes these above wishes come true. It is a command line based blog management tool for static web hosts, targeted primarily towards the github-pages platform. *ghournal <https://www.npmjs.com/package/ghournal> *exposes a git like command structure for blogging from the terminal. Creating a blog is as easy as 'ghournal init', adding a new post is as simple as 'ghournal new <postID>' etc. The complete command structure is documented in the project README. *ghournal <https://www.npmjs.com/package/ghournal>* is written in javascript and is available on npm. Hence installing and using it can not me easier. In short, it is designed to make the lives of developers who want to blog about their projects easier. So, if this sounds cool, please have a look at https://www.npmjs.com/package/ghournal and thanks :) sincerely Ganesh Prasad

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[config] Checking if put_time is in iomanip
by Edward Diener 04 May '16

04 May '16

Does anybody know of a way to check if the std::put_time functionality is part of iomanip ? It is supposed to be a part of C++11, but Boost.Config does not have any general way to check for C++11 that I know about. Nor do I find anything in SD-6 which would tell me if std::put_time is supported.

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[chrono] Header only library build and boost::system dependency
by Edward Diener 04 May '16

04 May '16

The documentation for chrono says: "How to Build Boost.Chrono as a Header Only Library? When BOOST_CHRONO_HEADER_ONLY is defined the lib is header-only. If in addition BOOST_USE_WINDOWS_H is defined <windows.h> is included, otherwise files in boost/detail/win are used to reduce the impact of including <windows.h>. However, you will either need to define BOOST_CHRONO_DONT_PROVIDE_HYBRID_ERROR_HANDLING or link with Boost.System. " So I have: #define BOOST_CHRONO_HEADER_ONLY #define BOOST_CHRONO_DONT_PROVIDE_HYBRID_ERROR_HANDLING #include <boost/chrono.hpp> followed by some code using chrono, and I still get when linking my exe: gcc.link C:\Programming\VersionControl\modular-boost\build\boost\bin.v2\libs\cxx_dual\test\test_chrono.test\gcc-mingw-5.3\debug\test_chrono.exe C:\Programming\VersionControl\modular-boost\build\boost\bin.v2\libs\cxx_dual\test\test_chrono.test\gcc-mingw-5.3\debug\test_chrono.o: In function `_static_initialization_and_destruction_0': E:\Programming\VersionControl\modular-boost\libs\cxx_dual\test/../../../boost/system/error_code.hpp:221: undefined reference to `boost::system::generic_category()' E:\Programming\VersionControl\modular-boost\libs\cxx_dual\test/../../../boost/system/error_code.hpp:222: undefined reference to `boost::system::generic_category()' E:\Programming\VersionControl\modular-boost\libs\cxx_dual\test/../../../boost/system/error_code.hpp:223: undefined reference to `boost::system::system_category()' collect2.exe: error: ld returned 1 exit status Is there a way to use chrono without having to link boost::system ?

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Naming convention of iterated binary operation
by Jeremy Murphy 03 May '16

03 May '16

Dear list entities, is there such a convention or precedent for naming an iterated binary operation? For example, Boost.Functional/Hash has an iterated hash() called hash_range(). I don't mind the "_range" suffix but I prefer the "iterated_" prefix based on the mathematical definition: https://en.wikipedia.org/wiki/Iterated_binary_operation The case in point is gcd() in Boost.Math: we want to provide an iterated gcd but we can't quite decide how to name it. I like the "iterated_" prefix but I would rather go with whatever might be the convention. Thanks, cheers. Jeremy

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[predef] check and require logical operators and multiple expression questions
by Edward Diener 01 May '16

01 May '16

Is there any difference in the result when you use the 'and' logical operator or simplty specify more than one expression: lib my_special_lib : source.cpp : [ predef-require "BOOST_OS_WINDOWS" and "BOOST_COMP_CLANG"] ; lib my_special_lib : source.cpp : [ predef-require "BOOST_OS_WINDOWS" "BOOST_COMP_CLANG"] ; Are both the above equivalent ? Can I use both 'and' and 'or' in an expression ? If so does 'and' bind before 'or' does, so that 'expression1 and expression2 or expression3' is conceptually '(expression1 and expression2) or expression3' ? Can I use parentheses to bind an expression with 'and' and 'or' ?

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boost chrono bad_cast (gcc > 4.9 on Mac)
by Min Yang Jung 01 May '16

01 May '16

Hi All, I was wondering if Boost.Chrono works with gcc > 4.9 on Mac. When system_clock::now() is called, it throws an std::bad_cast exception. The binary from the same code doesn’t have the issue if compiled with clang on Mac and gcc > 4.9 on Linux. The gcc compilers that I use are macport-installed gcc 4.9 and 5.0 (g++-mp-4.9 and g++-mp-5.0) on Mac. Any help would be appreciated. Thanks. Regards, Min Yang Jung

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Designing a multi-threaded file parser
by Aaron Boxer 30 Apr '16

30 Apr '16

Hello, I hope this is not off-topic, but I am interested in hearing about boost classes that will help me design the following: 1) I am designing a multi-threaded file parser for C++11 threads. The file format I am interested in parsing is a tagged format, with some tags requiring further processing, and others not. My working model right now is to have one thread through the file, and if it hits a tag that requires further processing, to push the file offset of this tag into a queue, to be processed by a thread pool. The read thread will spend a lot of time waiting for file IO to complete. Would it be faster to us the ASIO classes to do the reading? 2) I would like to design the following thread scheduling library to help process the tags: The library would have the following features: 1. smallest unit of work for a thread is a job 2. jobs have dependencies - job FOO cannot complete until job BAR has completed 3. threads are divided into groups 4. groups can be divided into bundles (a bundle can share the same processor affinity, for example) 5. groups are assigned to domains - domains contain jobs with similar characteristics, for example slow I/O activity 6. domains contain queues of jobs 7. threads in a group assigned to a domain can execute any jobs in any of the domain's queues Does boost support this type of thread scheduling framework? Can boost help me manage dependencies between jobs? Sorry for these broad design questions - just hoping for some insight into best design here. Many Thanks, Aaron

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[RFC] CallableTraits: 47 traits and metafunctions for "callable" types
by Barrett Adair 29 Apr '16

29 Apr '16

Hello all, I'm working on a project called CallableTraits [1]. Is there any interest in adding this to Boost? I think it would work well as an extension to Boost.TypeTraits. >From the introduction section: CallableTraits is a C++11/14/17 header-only library for the inspection, synthesis, and decomposition of callable types. Whether it's calling conventions, const volatile &&, or container-like manipulation of parameter lists, CallableTraits provides all the tools you need to completely rid your codebase of function type specializations. This project aims to be the "complete type manipulation facility for function types" mentioned in the last section of C++17 proposal p0172 [2]. CallableTraits currently supports GCC 4.8 and later, Clang 3.5 and later, AppleClang from XCode 6.3 and later, and MSVC 19. Much of the remaining documentation work lies in the reference sections. Many examples are provided, but many more are planned. Test coverage is good, but insufficient. Daily improvements are being made to address these issues. The headers amount to approximately 4200 lines of code, while the tests and examples tally around 6000 lines (excluding comments and blank lines). An "issues" list is maintained on GitHub [3]. Barrett [1]: http://badair.github.io/callable_traits/doc/html/index.html [2]: http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2015/p0172r0.html [3]: https://github.com/badair/callable_traits/issues

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Re: [boost] New Lib "Beast", HTTP + WebSocket protocols
by Vinnie Falco 29 Apr '16

29 Apr '16

On Fri, Apr 22, 2016 at 8:13 PM, David Stone <david(a)doublewise.net> wrote: > How does this compare to www.zaphoyd.com/websocketpp We have experience with websocketpp as it is the solution we have been using in our open source peer to peer software (http://github.com/ripple/rippled) for the last five years. It is that experience that drove the development of this new library as its replacement. Since the WebSocket protocol starts with a HTTP handshake, we also developed Beast.HTTP as an added bonus - think of it as a double feature at the drive-in. Beast.WebSocket has these things going for it: * Construct a stream from a socket or ssl::stream that's already connected or accepted: boost::asio::ip::tcp::socket sock(ios); websocket::stream<boost::asio::ip::tcp::socket> ws(std::move(sock)); * Accept a WebSocket handshake request with bytes that have already been read from the socket: template<class ConstBufferSequence> void websocket::stream::accept(ConstBufferSequence const& buffers); * Accept a WebSocket HTTP request handshake that was already parsed (e.g. from Beast.HTTP): template<class Body, class Headers> void websocket::stream::accept(http::request<Body, Headers> const& request); * Wraps any object meeting these type requirements, use your own type if you want: websocket::stream<YourTypeHere> ws(...); The type requirements (sync, async, or both): http://www.boost.org/doc/libs/1_60_0/doc/html/boost_asio/reference/SyncRead… http://www.boost.org/doc/libs/1_60_0/doc/html/boost_asio/reference/SyncWrit… http://www.boost.org/doc/libs/1_60_0/doc/html/boost_asio/reference/AsyncRea… http://www.boost.org/doc/libs/1_60_0/doc/html/boost_asio/reference/AsyncWri… * Receive functions accept any object meeting the requirements of Streambuf, permitting custom memory management strategies including the use of statically sized buffers. For example games using messages of fixed length. Streambuf type requirements: http://vinniefalco.github.io/beast/beast/types/Streambuf.html * In the Asio doc, Christopher Kohlhoff alludes to alternate implementation strategies for boost::asio::streambuf using multiple discontiguous buffers of varying sizes. We fulfill this idea with an optimized stream buffer that follows the strategy he described, providing a useful building block for sending and receiving variable size data. See: https://github.com/vinniefalco/Beast/blob/master/include/beast/basic_stream… * Interfaces are designed to closely resemble Asio in every possible way. This includes support for the extensible asynchronous model - support for std::future and stackful/stackless coroutines right out of the box. The library is designed to eliminate the learning curve for those familiar with Asio: extern void handle_read(boost::system::error_code ec); websocket::stream<boost::asio::ip::tcp::socket> ws(ios); ... websocket::opcode op; beast::streambuf sb; ws.async_read(op, sb, std::bind(&handle_read, std::placeholders::_1)); * All functions are template driven so everything is transparent to the compiler, including completion handlers passed to asynchronous initiation functions and objects used as buffers. By design, Beast.WebSocket avoids doing these things: * Managing the io_service * Managing a listening socket * Managing threads or a thread pool * Requiring the use of exceptions in certain places * Imposing a particular message buffering strategy * Using std::function for asynchronous callbacks * Requiring callers to know the size of the message in advance. The last point above is especially important for applications that produce data incrementally. For example, a huge JSON reply that comes from a database query. Planned improvements for Beast.WebSocket include: * Explicit proxy support with basic authentication * Tools for parsing subprotocols and message headers * permessage compression: https://tools.ietf.org/html/draft-ietf-hybi-permessage-compression-28 Years of experience working with Asio and and WebSockets have gone into the development of this library. It tries to be a natural extension of Asio, in a manner that is as narrow and lean as possible to provide maximum flexibility and performance.

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New Lib "Beast", HTTP + WebSocket protocols
by Vinnie Falco 28 Apr '16

28 Apr '16

"Beast" This is a new library that implements the HTTP and WebSocket protocols using Boost.Asio and a few other Boost tidbits. Here's a quick synopsis of what's in it: http::message: - class template modeling the HTTP message with customization points to satisfy even the most tough-minded reviewer. http::read http::write http::async_read http::async_write - Free functions to easily send and receive HTTP messages. Modeled to work exactly like boost::asio free functions. Role-agnostic, build clients or servers! websocket::stream - class template wrapping any asio sync or async stream. Implements the WebSocket protocol including the initial handshake. Examples: - websocket echo servers - HTTP servers for simple websites (no cgi) "I've heard enough, show me example code!" http://vinniefalco.github.io/beast/beast/intro/example.html Main page, with links to GitHub repository, HTML documentation and benchmarks: http://vinniefalco.github.io/ Feedback welcome, the author checks email and Issues on the GitHub repository. This project has been submitted to the Boost incubator.

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