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[iostreams] Devices and WOULD_BLOCK
by David Hawkins 30 Jan '15

30 Jan '15

Hi all, Boost newcomer here ... I have an application where I need to encode/decode a serialized data stream. I have used Boost.Iostreams filtering_stream filter to implement encoding and decoding function of each layer. The device interface is via a USB device, eg., think USB-to-Serial device, but without the classic Virtual COM Port or ttyUSB0 layer available. For example, the FTDI FT232H USB-to-MPSSE interface is a suitable cable http://www.ftdichip.com/Products/Cables/USBMPSSE.htm The cable can be used to implement either JTAG or SPI mode access (the mode selection introduces different filters into the filtering_stream stack). I have the filters working, and am working on getting a device working. Rather than deal with the details of the final hardware, I figured I'd simplify the design by creating a client/server design via sockets; the client code matches what I would use with real hardware, while the server code emulates the hardware. I started with this example for a socket device http://stackoverflow.com/questions/12023166/is-there-a-boostiostreams-bidir… The "problem" with the protocol I need to decode (which I have no choice to change) is that the data stream possibly contains escaped characters, so there is no way to know the read data length at the socket layer - its up to the filtering_stream layers to request data from the device layer until a complete packet is decoded. This all sounds good in theory, but in practice the filter layers attempt to read in blocks, and the read size is often larger than the read data that the device layer will supply. This lead to higher-level layers blocking in read(). I figured (perhaps incorrectly) that I could deal with this using non-blocking socket reads. After reading Boost.Iostreams non-blocking support in Section 3.6 http://www.boost.org/doc/libs/1_57_0/libs/iostreams/doc/index.html http://www.boost.org/doc/libs/1_57_0/libs/iostreams/doc/guide/asynchronous.… I modified the socket device example in the link above to; * put the socket in non-blocking mode before constructing the device * change the device 'read' procedure to return WOULD_BLOCK rather than throw an exception This does not work, and its not due to the filter layers. There is an issue with the device layer. Here's the issue ... given a design with a filtering_stream created only with a socket_device and no filters, if I trace the code in a debugger (Boost 1.57.0 source, Visual Studio 2012 under Win7), the socket_device read method call return sequence is boost/iostreams/read.hpp - read_device_impl read template at line 187 - read at line 52 boost/iostreams/detail/adapter/concept_adapter.hpp - device_wrapper_impl read at line 169 - read at line 77 boost/iostreams/detail/streambuf/indirect_streambuf.hpp - line 258 i.e., this source file https://github.com/boostorg/iostreams/blob/master/include/boost/iostreams/d… and this particular block of code // Read from source. std::streamsize chars = obj().read(buf.data() + pback_size_, buf.size() - pback_size_, next_); if (chars == -1) { this->set_true_eof(true); chars = 0; } setg(eback(), gptr(), buf.data() + pback_size_ + chars); The code tests for EOF (-1), but not WOULD_BLOCK (-2), so after this point, since chars is -2, things go bad. So I guess my question now is; Have I just bumped into the as-yet-unsupported part of Boost.Iostreams support for asynchronous I/O? Cheers, Dave PS. I can post example code if anyone wants to trace the code for themselves, I just figured I'd post the question to start with.

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Joining boost::asio::strands
by Cesar Mello 29 Jan '15

29 Jan '15

Hi, After spawning several paralell jobs through calls to boost::asio::spawn inside a loop, is there an easy way to wait for all of them to finish? I would like to join them to aggregate the results. Please can you give me any clue? Thank you a lot! Best regards Cesar

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ProgramOptions: explicit empty string argument
by Akim Demaille 29 Jan '15

29 Jan '15

Hi, I would like to be able to support an empty optional argument for long options. This is something that is supported by gnu getopt_long and argp. Consider for instance a simplified version of the first simple example program: #include <iostream> #include <boost/program_options.hpp> int main(int ac, char* av[]) { namespace po = boost::program_options; using namespace std; po::options_description desc("Allowed options"); desc.add_options() ("help", "produce help message") ("compression", po::value<string>()->implicit_value(""), "set compression level") ; po::variables_map vm; po::store(po::parse_command_line(ac, av, desc), vm); po::notify(vm); if (vm.count("help")) cout << desc << "\n"; else if (vm.count("compression")) cout << "Compression level was set to " << vm["compression"].as<string>() << ".\n"; else cout << "Compression level was not set.\n"; } when I run it, in "typical cases", I have: $ ./a.out Compression level was not set. $ ./a.out --compression=foo Compression level was set to foo. $ ./a.out --compression foo Compression level was set to foo. $ ./a.out --compression Compression level was set to . all of this is fine. However, how can I explicitly pass the empty string? $ ./a.out --compression= libc++abi.dylib: terminating with uncaught exception of type boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::program_options::invalid_command_line_syntax> >: the argument for option '--compression' should follow immediately after the equal sign zsh: abort ./a.out --compression= Of course I could simply to my user that there is a special token, say '-', that means "empty", but it is still more complex than simply accepting the empty string to mean the empty string. Thanks! (There are some stack overflow questions, but they do not address this particular point, --foo='').

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[interprocess] Bizarro File Names (Windows)
by Aaron_Wright＠selinc.com 28 Jan '15

28 Jan '15

I have a service that is running in Windows Server 2008 R2 SP1 that uses shared memory. It runs fine for a month or so, but then stops working correctly. When I check the C:\ProgramData\boost_interprocess\*\ folder, I get a bunch of weird file names, such as: 88C861CD6DE2CF01EBA2F0CC1200D001A4070000EBFFFFFF 88C861CD6DE2CF01EBA2F0CC1200D001A4070000ECFFFFFF 88C861CD6DE2CF01EBA2F0CC1200D001A4070000EDFFFFFF 88C861CD6DE2CF01EBA2F0CC1200D001A4070000EEFFFFFF 88C861CD6DE2CF01EBA2F0CC1200D001A4070000EFFFFFFF 88C861CD6DE2CF01EBA2F0CC1200D001A4070000F0FFFFFF 88C861CD6DE2CF01EBA2F0CC1200D001A4070000F1FFFFFF 88C861CD6DE2CF01EBA2F0CC1200D001A4070000F2FFFFFF 88C861CD6DE2CF014B04F3CC1200D001A40700000AFFFFFF 88C861CD6DE2CF014B04F3CC1200D001A40700000BFFFFFF 88C861CD6DE2CF014B04F3CC1200D001A40700000CFFFFFF 88C861CD6DE2CF014B04F3CC1200D001A40700000DFFFFFF ... (and so on) These are not even close to the names that are supposed to be used. They seem to increment a bit, then shift slightly, and start incrementing again. When I restart the service I get similar named files and patterns, and my services crashes because it can't grow shared memory (presumably because the file names are not correct). I have to restart the box in order to get the correct behavior. Has anyone seen this behavior before? --------------------------------------------------------- Aaron Wright

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[mpl] lazy condition in enable_if
by Sam Fisher 28 Jan '15

28 Jan '15

Hi, I need to run boost::mpl::for_each<> function with template condition, like: boost::mpl::for_each< vector_of_types, boost::mpl::make_identity<boost::mpl::_1> > (Functor< condition >()); I'm trying to implement lazy binding in enable_if. Visual studio fails with error "'X<IsFoo<boost::mpl::_>>::operator ()' : ambiguous call to overloaded function" minimal test code which fail on boost 1.57 #include <boost/mpl/for_each.hpp> #include <boost/mpl/lambda.hpp> #include <boost/mpl/bind.hpp> #include <boost/mpl/vector.hpp> #include <boost/core/enable_if.hpp> #include <iostream> #include <type_traits> template <int> struct dummy { dummy(int) {} }; // from doc struct Foo {}; struct Bar {}; template <typename T> struct IsFoo { typedef typename std::is_same<T, Foo>::type type; }; #define generate_type(_fn) \ typename boost::mpl::apply<boost::mpl::bind< \ boost::mpl::lambda< _fn <boost::mpl::_> >::type, \ boost::mpl::bind<typename boost::mpl::lambda<_Pred>::type, U> \ > >::type #define enable_type generate_type(boost::enable_if) #define disable_type generate_type(boost::disable_if) template <typename _Pred> struct X { template <typename U> enable_type operator()(boost::mpl::identity<U>, dummy<0> = 0) const { std::cout << "enable: " << typeid(U).name() << std::endl; } template <typename U> disable_type operator()(boost::mpl::identity<U>, dummy<1> = 0) const { std::cout << "disable: " << typeid(U).name() << std::endl; } }; int main() { X<IsFoo<boost::mpl::_> > x; x(boost::mpl::identity<Foo>()); x(boost::mpl::identity<Bar>()); return 0; }

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[release] Release schedule changes..
by Rene Rivera 27 Jan '15

27 Jan '15

After some discussion in the Boost Release Team we've decided on an ongoing schedule for releases. Taking into account the realities of how long it takes for authors and the release team to work on a release we've decided to move to *three* releases a year. The targets for the releases will now be: * Spring release on the second Wednesday of April. * Summer release on the second Wednesday of August. * Fall/Winter release on the second Wednesday of December. There will be no January release. This will allow for the fact that most people are on extended holidays during Winter. It will also allow for people to work on larger changes that require more testing time during the longer Winter period. We are also moving to Wednesday release to allow the release managers non-weekend time to work before and after the release. Please consult the Boost calendar for specific dates and merge schedule for the next release. Thanks, the Boost Release Team. -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net -- rrivera/acm.org (msn) - grafikrobot/aim,yahoo,skype,efnet,gmail

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[multi state machine/ MSM] execute_queued_events
by Steve Hickman 26 Jan '15

26 Jan '15

In the MSM doc section "Enqueueing events for later processing", you state that "Calling execute_queued_events() will then process all enqueued events (in FIFO order)." You also said in a previous post that MSM is not thread safe, thus requiring an external mechanism to insure thread safety. I don't see a mechanism to execute a single event at a time, which would be preferable if I have to lock the queue while processing events. Having said that, a cursory examination of the "execute_queued_events" code makes me think it only processes one event per call. Which is correct? Is the documentation correct that it actually processes all queued events? If not, can the documentation be corrected? If so, is there a publicly usable call to process a single queued event? If there is no publicly available call for processing a single queued event, how do you recommend processing queued events in a thread safe manner that won't lock the queue for extended periods of time?

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[multi_index] recursive declaration of MIC with a value which contains references of its kind
by Nick Stokes 26 Jan '15

26 Jan '15

I have a value type (Foo) which is supposed to contain references to some multi_index_container of its type, like so: struct Foo { int property1; int property2; FooMIC* other; // this (the pointer value) may or may not be indexed upon }; typedef multi_index_container< Foo, indexed_by < sequenced<> , ordered_unique< member<Foo, int, &Foo::property1> > , ... >> FooMIC; Due to recursive nature of this, I wasn't able to figure out how do declare such a thing (other than unsafely using void* references in Foo). Any ideas? Thanks many, Nick

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Re: [Boost-users] [boost] [Review] Boost.Endian mini-review
by Beman Dawes 26 Jan '15

26 Jan '15

On Sun, Jan 25, 2015 at 6:12 PM, Jason Newton <nevion(a)gmail.com> wrote: > On Sun, Jan 25, 2015 at 8:21 AM, Beman Dawes <bdawes(a)acm.org> wrote: > >> On Sat, Jan 24, 2015 at 2:25 AM, Jason Newton <nevion(a)gmail.com> wrote: >> > I think the only thing that I have no interest in using - a kind way of >> > saying its probably unneeded bloat IMO is the arithmetic types. I prefer >> > native types and using conversion functions. But maybe they could >> improve >> > my code - its something I toss back and forth a little and haven't >> > attempted embracing. >> >> Because even the endian buffer and arithmetic types that appear most >> expensive generate only short sequences of code, the optimizing >> compilers often generate exactly the same instructions regardless of >> endian approach. On Intel machines, that often distills down to a >> single bswap instruction since the value is already in a register. >> >> That isn't always true, so you do need to measure performance of >> various approaches in the context of your actual application. But if >> use of the buffer or arithmetic types would otherwise improve your >> code, please don't reject them without actually testing performance >> first. >> > > Allow me to clarify: I meant code bloat, not speed. Sorry - your original post was clear, but I misinterpreted. I have not systematically measured code bloat. Maybe I can do that at least for some common use cases. Thanks, --Beman

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Re: [Boost-users] [boost] [Review] Boost.Endian mini-review
by Beman Dawes 25 Jan '15

25 Jan '15

On Sat, Jan 24, 2015 at 2:25 AM, Jason Newton <nevion(a)gmail.com> wrote: ... > As a long time user of the Boost.Endian library (applying patches to the > distribution I maintain), I am happy to see it finally up for uh... > mini-review. Hoping to see it get to formal review and included... further > hoping it makes it into the next C++ standard! The library went through formal review in 2011, so will go into Boost as soon as the mini-review is over. And, yes, I do plan to propose it to the standards committee. > It is ready in my opinion. I've seen it go through some topical changes > over the years but the only thing I've used from it are the conversion > functions which have been great for implementing proper io in the range of > network socket io / serial with various protocols and stored data from > varies devices/sensors) if a specification enforces byte order. It > fullfills my needs and always did fairly well on performance with gcc/clang. Depending on what version you have been using, the performance may now be even better. > I think the only thing that I have no interest in using - a kind way of > saying its probably unneeded bloat IMO is the arithmetic types. I prefer > native types and using conversion functions. But maybe they could improve > my code - its something I toss back and forth a little and haven't > attempted embracing. Because even the endian buffer and arithmetic types that appear most expensive generate only short sequences of code, the optimizing compilers often generate exactly the same instructions regardless of endian approach. On Intel machines, that often distills down to a single bswap instruction since the value is already in a register. That isn't always true, so you do need to measure performance of various approaches in the context of your actual application. But if use of the buffer or arithmetic types would otherwise improve your code, please don't reject them without actually testing performance first. > > This library should not be looked at as fulfilling an uncommon need - and > should even be part of future C++ standards because the usual > macro/functions (e.g. htons) in the in arpa/inet.h are widely used outside > of inet related code (see above examples) and have the types encoded in the > name making them not easily usable/composable in contrast to something > template based which the library offers. Further IEEE 754 support - > especially for double floating point types. The library definitely fills > that gap and has for years IMO. Thanks for the kind words! --Beman

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[thread] await hangs when using boost::promise/future
by TONGARI J 25 Jan '15

25 Jan '15

Hi, The sample code is here: https://gist.github.com/jamboree/3b8716ad1922749e77ae The boost::future adaption code is adapted from N4286. Tested with VS2015 preview. If std::promise is passed, the code works fine. Any clue why it hangs if boost::promise is passed? Thanks.

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[Graph] source vertex colour at start of BFS or DFS
by Jeremy Murphy 24 Jan '15

24 Jan '15

Hi, I'm wondering, why do the BFS and DFS algorithms not inspect the colour of the source vertices given to them? If a source vertex is already black, shouldn't the search effectively be a no-op? Currently the source vertex is 'discovered' and coloured grey regardless of its previous colour. I know it might seem weird to pass a black vertex as the source, but I guess I see it as similar to passing an empty range to an algorithm: it's valid but nothing happens. Thanks, cheers. Jeremy

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Re: [Boost-users] unit test BOOST_CHECK_CLOSE absolute
by Dave Gomboc 24 Jan '15

24 Jan '15

Gennadiy Rozental <rogeeff <at> gmail.com> writes: > > Paul A. Bristow <pbristow <at> hetp.u-net.com> writes: > > FWIW I've also wanted the *values* in a message (rather > > than just a test fail). > > I do not follow this comment. Which message and which tool do you refer to? Perhaps he meant that he'd like the error message when a BOOST_CHECK_CLOSE fails to show the value that was rejected, and also the range of values that would have been accepted? Dave

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[Review] Boost.Endian mini-review
by Joel FALCOU 23 Jan '15

23 Jan '15

The mini-review of Boost.Endian starts today and runs through Sunday, February 1. The library repository is available on GitHub at https://github.com/boostorg/endian The docs for the library can be viewed online at https://boostorg.github.io/endian/ The objective of the mini-review is to verify that the issues raised during the formal review have been addressed. Those issues are documented at https://boostorg.github.io/endian/mini_review_topics.html which also describes the resolution of each issue. Comments and suggestions unrelated to the mini-review issues are also welcome, but the key question the review manager needs your opinion on is this: Is the library ready to be added to Boost releases? -- Joel Falcou, Endian Review Manager

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Review Wizard Status Report for January 2015
by Ron Garcia 23 Jan '15

23 Jan '15

============================================== Review Wizard Status Report for January 2015 ============================================== News ==== 1. Boost 1.56 Released November 2014. New Libraries: none 2. Sort Accepted. November 2014. 3. Compute Accepted. December 2014. Open Issues =========== The following libraries have review managers, but have not yet been scheduled for review: * Range Extensions - added May 2012; review manager: Neil Groves. The following libraries have been accepted to Boost, but have not yet been integrated into Boost Git: * Contract - accepted September 2012; author: Lorenzo Caminiti. * Sort - accepted November 2014: author: . * Compute - accepted December 2014: author: . The following libraries have been accepted and submitted to Boost Git, but have not yet appeared in a release: * Convert - accepted June 2014; author: Vladimir Batov. The following libraries have been accepted provisionally to Boost, but have not been submitted for mini-review and full acceptance: * Endian - accepted provisionally September 2011; author Beman Dawes. * Fiber - accepted provisionally January 2014; author Oliver Kowalke. General Announcements ===================== As always, we need experienced review managers. Please take a look at the list of libraries in need of managers and check out their descriptions. In general review managers are active boost participants, including library contributors, infrastructure contributors, and other mailing list participants with a substantial track record of constructive participation. If you can serve as review manager for any of them, email Ron Garcia or John Phillips, "rxg at cs dot ubc dot ca" and "johnphillipsithica at gmail dot com" respectively. We are also suffering from a lack of reviewers. While we all understand time pressures and the need to complete paying work, the strength of Boost is based on the detailed and informed reviews submitted by you. If you are interested in reviewing a library but won't have time during the review period, you can always prepare your review ahead of time. No rule says you can only work on a review during the review period. A link to this report will be posted to www.boost.org. If you would like us to make any modifications or additions to this report, please email Ron or John. The review schedule is an unordered list of the libraries awaiting review. As such, any library on the schedule can be reviewed once the developer is ready, a review manager has been secured, and the manager, developer, and wizards agree on a date to schedule the review. Review Schedule =============== * Join (M) * Sorting (M) * Quaternions, Vectors, Matrices (M) * Block Pointer (M) * Singularity (M) * Extended Complex Numbers (M) * Metaparse (M) * Boost.Range Extensions * Nowide (M) * Array (M) * STL Extensions (M) * Countertree (M) * Process (M) * Asynchronous File I/O (M) * Application (M) * Edit Distance (M) * Mixin (M) * Dependency Injection (M) * DLL (M) ``(M)`` marks libraries that need review managers. -------------------- Join ---- :Author: Yigong Liu :Review Manager: Needed :Download: http://channel.sourceforge.net/ :Description: Join is an asynchronous, message based C++ concurrency library based on join calculus. It is applicable both to multi-threaded applications and to the orchestration of asynchronous, event-based applications. It follows Comega's design and implementation and builds with Boost facilities. It provides a high level concurrency API with asynchronous methods, synchronous methods, and chords which are "join-patterns" defining the synchronization, asynchrony, and concurrency. Sorting ------- :Author: Steven Ross :Review Manager: Needed :Download: https://github.com/boost-vault/Sorting :Description: A grouping of 3 templated hybrid radix/comparison-based sorting algorithms that provide superior worst-case and average-case performance to std::sort: integer_sort, which sorts fixed-size data types that support a rightshift (default of >>) and a comparison (default of <) operator. float_sort, which sorts standard floating-point numbers by safely casting them to integers. string_sort, which sorts variable-length data types, and is optimized for 8-bit character strings. All 3 algorithms have O(n(k/s + s)) runtime where k is the number of bits in the data type and s is a constant, and limited memory overhead (in the kB for realistic inputs). In testing, integer_sort varies from 35% faster to 2X as fast as std::sort, depending on processor, compiler optimizations, and data distribution. float_sort is roughly 70% faster than std::sort. string_sort is roughly 2X as fast as std::sort. Quaternions, Vectors, Matrices ------------------------------ :Author: Emil Dotchevski :Review Manager: Needed :Download: http://www.revergestudios.com/boost-qvm/ :Description: QVM defines a set of generic functions and operator overloads for working with quaternions, vectors and matrices of static size. The library also defines vector and matrix data types, however it allows users to introduce their own types by specializing the q_traits, v_traits and m_traits templates. Block Pointer ------------- :Author: Phil Bouchard :Review Manager: Needed :Download: https://svn.boost.org/svn/boost/sandbox/block_ptr/ :Description: Deterministic memory manager of constant complexity capable of handling cyclic collections. Singularity ----------- :Author: Ben Robinson :Review Manager: Needed :Download: https://github.com/cppmaven/Singularity :Description: The Singularity Design Pattern allows you to restrict any class to a single instance. Unlike the infamous Singleton, Singularity gives you direct control over the lifetime of the object, does not require you to grant global access to the object, nor does it limit you to the default constructor for that object. Extended Complex Numbers ------------------------ :Author: Matthieu Schaller :Review Manager: Needed :Download: http://code.google.com/p/cpp-imaginary-numbers/ :Description: The library is an extension of the std::complex class addressing two issues: 1. The standard does not guaranty the behaviour of the complex class if instantiated with types other than float/double/long double. 2. Some calculation where pure imaginary numbers (i.e. multiples of sqrt(-1)) appear are unnecessarily slowed down due to the lack of support for these numbers. The code I submit contains two interleaved classes boost::complex and boost::imaginary which can be instantiated with any type T provided T overloads the usual arithmetic operators and some basic (real) mathematical functions depending on which complex function will be used. It is thus an extended version of Thorsten Ottosen's n1869 proposal (http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2005/n1869.html) Metaparse --------- :Author: Abel Sinkovics :Review Manager: Needed :Download: http://abel.web.elte.hu/metaparse/metaparse.zip :Description: Metaparse is a library for constructing parsers parsing at compile-time based on template metaprogramming. The parsers built with the library take boost::mpl::strings as input and can produce - types - objects (types with public static members) - callable C++ functions (types with public static method) - template metafunction classes as output (based on the input being parsed). On compilers supporting constexpr the library provides the following syntactic sugar for writing the input of the parsers: BOOST_STRING("this is a string") The library can be used for implementing DSLs in C++, including DSLs making C++ template metaprogramming easier (see examples). Range Extensions ---------------- :Author: Akira Takahashi :Review Manager: Neil Groves :Download: https://github.com/faithandbrave/OvenToBoost :Description: This project adds some features of the Oven Range Library to Boost.Range. Features: - Additional Range Adaptors (taken, taken_while, dropped, dropped_while, elements, elements_key, memoized, outdirected) - Extensions for using Lambda (regular function, regular operator) - Infinite Range (iteration function) - and additional range utilities. Nowide ------ :Author: Artyom Beilis :Review Manager: Needed :Download: http://cppcms.com/files/nowide/ :Description: This library makes cross platform Unicode aware programming easier. It 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. Array ----- :Author: Brian Smith :Review Manager: Needed :Download: https://github.com/BrianJSmith/Array :Description: The array class is a C++11 compatible implementation of static multidimensional arrays. STL Extensions -------------- :Author: Vadim Stadnik :Review Manager: Needed :Download: https://github.com/vstadnik/stl_ext_adv_review :Description: The proposed library [stl_ext_adv] offers augmented array based B+ trees and STL containers that support the interfaces of the C++03 sequences and associative containers. The library offers a number of extensions and performance improvements that are not available in C++03 and C++11 standard containers. Countertree ----------- :Author: Francisco Jose Tapia :Review Manager: Needed :Download: https://dl.dropbox.com/u/8437476/works/countertree_code_doc.zip :Description: This library is an implementation of a binary red-black counter tree. This tree have an additional counter in each leaf. This permit the access to the elements by the position, like in a vector. It is a random access container with random access iterators. COUNTERTREE This kind of trees have an additional counter in each leaf. This permit the access to the elements by the position, like in a vector. It is a random access container with random access iterators. With unordered information we have a vector with the same speed inserting and deleting in any position (O(log N)). With ordered information, we have the classes set, multiset, map and multimap, with identical interface than the STL classes, with the plus of access to the elements by position, like in a vector. The iterators are random access , and you can subtract them. SUBALLOCATOR The suballocator is a layer between the allocator and the data structures, compatible with any allocator with the STL definition. The suballocator replace to the allocator in the allocation of equal size elements. It provides speed, return the unused memory and decrease the memory used by the program and improve the cache performance due to the data locality improvement ( 30% of improvement of speed respect the std::allocator with GCC 4.7) Process ------- :Author: Boris Schaeling :Review Manager: Needed :Download: http://www.highscore.de/boost/process0.5/process.zip :Description: Boost.Process is a 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 Asynchronous File I/O --------------------- :Author: Niall Douglas and Paul Kirth :Review Manager: Needed :Download: https://github.com/BoostGSoC/boost.afio/archive/boost-peer-review.tar.gz :Description: Boost.AFIO is a linear scalable, batch, chainable, asynchronous closure execution engine with an almost wait free implementation extending Boost.ASIO and Boost.Thread specialised as a portable asynchronous file i/o implementation library. Implementation of this first version has been kept as simple as possible (~ 1000 active LOC) at the cost of some performance, though with a good compiler you can expect 25-50% of the performance of using raw Boost.ASIO. Application ----------- :Author: Renato Tegon Forti :Review Manager: Needed :Download: https://github.com/retf/Boost.Application :Documentation: http://www.dokfile.com/appbeta4/docs/libs/application/doc/html/index.html :Description: Application provides an application environment, or start point to any people that want a basic infrastructure to build an system application on Windows or Unix Variants (e.g. Linux, MacOS). Application uses behaviours modeled using 'aspects' concept proposed by 'Vicente J. Botet Escriba', that allow easy extension and customization of library components. The application modes uses these components internally to achieve the user desirable behaviours. Application provide many useful ready-to-use features, e.g: * Run application as Windows Service; * Run application as UNIX/POSIX Daemon; * Plugin extension system; * Process(executable) Single instance Instantiation support; * Application SIGNAL/Callbacks customization; * Windows Service Setup feature; * And many others. Edit Distance ------------- :Author: Erik Erlandson :Review Manager: Needed :Download: https://github.com/erikerlandson/algorithm/tree/edit_distance/sequence :Description: The edit distance is the length of the shortest (or least-cost) edit script from one sequence to another, where an edit script is defined as a sequence of insertion, deletion and (optionally) substitution operations. The function implementing the edit distance is named edit_distance. This function will return the edit distance between two sequences, where sequences may be any valid range object supporting forward iteration. The edit_distance function will also, if requested, return the edit script. Mixin ----- :Author: Borislav Stanimirov :Download: https://github.com/iboB/boost.mixin :Documentation: http://ibob.github.io/boost.mixin/ :Review Manager: Needed :Description: Boost.Mixin is a library that allows the composition and modifications of polymorphic types at run time. Types and objects are constructed out of building blocks called mixins. The library uses the type boost::mixin::object as a placeholder, whose instances can be extended with existing classes (mixins), thus providing a particular instance with the functionality of all those types. Accessing the newly formed type's interface is made through messages: stand-alone functions generated by the library, which can be thought of as methods. This is given while also having full abstraction between the interface and the definition of types. An existing feature in another language similar to Boost.Mixin and also an inspiration for the library are the mixins in Ruby. The library also has similarities with the pattern entity-component-system. Dependency Injection -------------------- :Author: :Download: https://github.com/krzysztof-jusiak/di :Documentation: http://krzysztof-jusiak.github.io/di/boost/libs/di/doc/html :Incubator: http://rrsd.com/blincubator.com/bi_library/di-dependency-injection/?gform_p… :Review Manager: Needed :Description: Boost.DI is a dependency injection library improving manual dependency injection by simplifying object instantiation with automatic dependencies injection. Using Boost.DI has many advantages over manual dependency injection. * Reduce boilerplate code (No factories, no objects creation in specific order) * Reduce cost of maintenance effort (Constructor signature change won't affect di configuration) * Reduce testing effort * Give better control of what and how is created (Policies, Providers) * Give better understanding about objects hierarchy (UML Dumper) DLL --- :Author: Antony Polukhin :Download: https://github.com/apolukhin/Boost.DLL :Documentation: http://apolukhin.github.io/Boost.DLL/index.html :Review Manager: Needed :Description: This library was designed to simplify plugin development using C++ in a portable cross-platform manner. Library provides a portable across platforms way to: * load libraries * import any native functions and variables * make alias names for C++ mangled functions and symbols * query libraries for sections and exported symbols * self loading and self querying * getting program and module location by exported symbol Libraries under development =========================== See The Boost Library Incubator Project at http://blincubator.com for discussion of libraries currently under development.

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problems building Boost-1.55.0 in 32b machines with c++11
by Patricia Mendez Lorenzo 22 Jan '15

22 Jan '15

Dear Boost experts, since a while I am trying to compile Boost from the source in a 32b linux machine with c++11 enabled. The compiler version used is gcc4.8.1 This is performed through cmake as follows: --> Configuration: bootstrap.sh --with-python=<path to /bin/python> --with-toolset=gcc --> Build: /b2 -j4 variant=release --layout=versioned --debug-configuration --toolset=gcc --user-config=<path to a user-config.jam> Where user-config.jam contains the following information: using gcc : : : <linkflags>-m32 <compileflags>-m32 -std=gnu++0x also tested it with -std=c++11 And finally installed which basically contains the same options as the build adding --prefix=<installation dir> The libraries built following this procedure does not seem to have been created with c++11. If I compare the signatures of the same library build in 64 against 32 the result are In 64: nm --defined-only --demangle libboost_filesystem-gcc48-mt-1_55.so | grep copy_file boost::filesystem::detail::copy_file(boost::filesystem::path const&, boost::filesystem::path const&, boost::filesystem::copy_option, boost::system::error_code*) In 32, the same produces: boost::filesystem::detail::copy_file(boost::filesystem::path const&, boost::filesystem::path const&, boost::filesystem::copy_option::enum_type, boost::system::error_code*) The difference seems to come from wrong i686 build options. Could you please help me to find the good options to build these libs in 32b with c+=11 enabled? Thank you so much,

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Question about subgraph isomorphism function
by Shouwei Li 20 Jan '15

20 Jan '15

Hi Guys, I am using boost graph library in my research project about graph theory. One object is testing whether graph G1 has a subgraph isomorphic to another graph G2. I only care about the result, "yes" or "no", and don't expected to find out a isomorphism pattern. I use the library function vf2_subgraph_iso(), but the third parameter is a callback function which will print out the isomorphic pattern all the time. Is there any way to omit this parameter or eliminate the output pattern. Here is my code snippet: ----------------------------------------------------- vf2_print_callback<Graph, Graph> callback(C4, g); if (!vf2_subgraph_iso(C4, g, callback) { // something; } else { // something; } __________________________________ Thanks for you attention! Best Regards! Shouwei

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How to build modular boost for android?
by Robert Dailey 19 Jan '15

19 Jan '15

How do I build modular boost for android? I have it checked out from github at the 1.57 tag. I don't see a user-config.jam file, except for at "tools/build/example/user-config.jam". The structure is completely changed, where do I need to make changes? What changes do I make? Any guidance is appreciated. I'm no where near an expert here, I just need a quick ad-hoc solution. Thanks.

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[interval] Guaranteed interval arithmetic for "long double"
by Александров Петр 15 Jan '15

15 Jan '15

Hello. Is guaranteed interval arithmetic for "long double" supported by Boost Interval library on x86-64 CPU, Linux, Clang or GCC? Kind regards, Petr.

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[Coroutine] Migrating coroutines between different threads
by lin li 15 Jan '15

15 Jan '15

Hi, people. I have a question about the coroutines in boost (both the normal Coroutine and the asio couroutine). Can I suspend a coroutine in one thread, then later on resume it in another thread? I have been googling about this and found some (outdated) documents saying that this is not possible ( http://www.crystalclearsoftware.com/soc/coroutine/coroutine/coroutine_threa… ). However, I did not find this warning in the document of the current release. Is this limitation still there or not?

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init log with BOOST_LOG_INLINE_GLOBAL_LOGGER_DEFAULT
by Bill Tian 15 Jan '15

15 Jan '15

Hi guys, I want to define a global logger that can be used in other place. The severity level always be "info". I init the log like this: #include <cstdlib> #include <boost/log/trivial.hpp> #include <boost/log/core.hpp> #include <boost/log/sources/global_logger_storage.hpp> #include <boost/log/sources/severity_logger.hpp> #include <boost/log/sources/record_ostream.hpp> #include <boost/log/sources/severity_feature.hpp> // Here we define our application severity levels. enum severity_level { normal, notification, warning, error, critical }; // The formatting logic for the severity level template< typename CharT, typename TraitsT > inline std::basic_ostream< CharT, TraitsT >& operator<< (std::basic_ostream< CharT, TraitsT >& strm, severity_level lvl) { static const char* const str[] = { "normal", "notification", "warning", "error", "critical" }; if (static_cast<std::size_t>(lvl) < (sizeof(str) / sizeof(*str))) strm << str[lvl]; else strm << static_cast<int>(lvl); return strm; } // Global logger declaration BOOST_LOG_INLINE_GLOBAL_LOGGER_DEFAULT(test_lg, boost::log::sources::severity_logger_mt<severity_level>) void try_logging() { boost::log::sources::severity_logger_mt<severity_level>& lg = test_lg::get(); // TODO: // always write "info" record, Unknown reason! BOOST_LOG_SEV(lg, normal) << "This is a normal severity record"; BOOST_LOG_SEV(lg, notification) << "This is a notification severity record"; BOOST_LOG_SEV(lg, warning) << "This is a warning severity record"; BOOST_LOG_SEV(lg, error) << "This is a error severity record"; BOOST_LOG_SEV(lg, critical) << "This is a critical severity record"; } int main(int argc, char* argv[]) { try_logging(); return EXIT_SUCCESS; } In the log i got this: [2015-01-14 19:00:34.800935] [0x40000300] [info] This is a normal severity re cord [2015-01-14 19:00:34.805935] [0x40000300] [info] This is a notification sever ity record [2015-01-14 19:00:34.806935] [0x40000300] [info] This is a warning severity r ecord [2015-01-14 19:00:34.806935] [0x40000300] [info] This is a error severity rec ord [2015-01-14 19:00:34.806935] [0x40000300] [info] This is a critical severity record What do i miss? Thank you! Bill

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Re: [Boost-users] unit test BOOST_CHECK_CLOSE absolute
by lepere renaud 14 Jan '15

14 Jan '15

>> For example, I am comparing coordinates in 2d spaces and the relative >> value is not important, the meaningfull value is the absolute difference >> between coordinates. > > It is almost never true. Related error gives you much better estimate of > closeness. I agree with that most of the time but this is not always true. Just imagine the case you compare lattitude, longitude. In this case, only absolute values make sense. > >> I have seen that I can do a >> BOOST_CHECK_SMALL(fabs(x - expected_x), 1e-3); >> >> but in this can I don't have a good message when the test fails (it does >> not show the value of x and the expected_x). >> >> In fact I would like to have something like BOOST_CHECK_CLOSE_ABSOLUTE ? >> Is there something equivalent or how can I do something like this ? > > Don't. Specify relative tolerance (or percent tolerance) and keep using > BOOST_CHECK_CLOSE. Relative tolerance will give me false bug report, I want a point to be equal to (0, 0) with a small absolute error and I don't care if it is -1e-15 or +1e-10 so BOOST_CHECK_CLOSE is not an option here and I have to use BOOST_CHECK_SMALL with the absolute difference. The problem with BOOST_CHECK_SMALL(fabs(x - expected_x), 1e-3); Is that when it fails with the message that does not print the values "x" and "expected_x" and does not say something like x(2.0) is not equal to "expected_x(0.0)" with an difference of 1e-3. I can probably write my own macro combining BOOST_TEST_MESSAGE() and some glues to obtain what I want but I was wondering if someone had the same problem and a solution. Thanks Renaud

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[Boost.build] Building for ARM64
by mefyl 14 Jan '15

14 Jan '15

Hi, In my quest cross-compiling Boost.Context for ARM64, I encounter the following problem (using develop since ARM64 support is not in 1.57): $ ./bootstrap.sh --with-libraries=context [...] $ ./b2 -d2 -q toolset=clang architecture=arm abi=aapcs address-model=64 binary-format=mach-o [...] "clang++" -o "bin.v2/libs/system/build/clang-darwin-4.2.1/release/abi- aapcs/address-model-64/architecture-arm/threading-multi/libboost_system.dylib" -single_module -dynamiclib -install_name "libboost _system.dylib" "bin.v2/libs/system/build/clang-darwin-4.2.1/release/abi- aapcs/address-model-64/architecture-arm/threading-multi/error_code.o" Despite asking for arm, the "-arch arm64" I would expect is not passed to clang which thus compile to x86_64. However Boost.Context DOES understand I'm targeting arm since it picks the right ASM file: "clang++" -x assembler-with-cpp -O3 -O3 -finline-functions -Wno-inline - Wall -fPIC -DBOOST_ALL_NO_LIB=1 -DBOOST_CHRONO_DYN_LINK=1 - DBOOST_CONTEXT_DYN_LINK=1 -DBOOST_CONTEXT_SOURCE -DBOOST_SYSTEM_DYN_LINK=1 - DBOOST_SYSTEM_NO_DEPRECATED -DBOOST_THREAD_BUILD_DLL=1 -DBOOST_THREAD_POSIX - DBOOST_THREAD_USE_DLL=1 -DNDEBUG -I"." -c -o "bin.v2/libs/context/build/clang- darwin-4.2.1/release/abi-aapcs/address-model-64/architecture-arm/threading- multi/asm/make_arm64_aapcs_macho_gas.o" "libs/context/src/asm/make_arm64_aapcs_macho_gas.S" Which yields assembly errors of course since "-arch arm64" is not passed. Other sources seem to manage to build Boost for ARM64 using darwin toolset forcing clang as the compiler and passing many additional options, but their setup fails to build Boost.Context since it either picks the wrong ASM file, either complains the platform is not supported. Thanks in advance ! -- Quentin "mefyl" Hocquet CTO @ infinit.io

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Ambiguous overload for boost::blank when using optional & variant
by Berteun Damman 14 Jan '15

14 Jan '15

Hi, I'm using boost 1.57 after upgrading from 1.50, and the following innocuous looking program does not compile with either GCC (4.9) or Clang (3.5); tested both on Mac & Linux: #include <boost/optional.hpp> // This header triggers the problem #include <boost/variant.hpp> int main() { boost::variant<boost::blank> a, b; swap(a,b); // a.swap(b) does not make a difference } Both GCC and Clang give the same error: /opt/local/include/boost/variant/detail/move.hpp:60:5: error: call to 'swap' is ambiguous swap(lhs, rhs); [....] /opt/local/include/boost/core/swap.hpp:54:8: note: candidate function [with T1 = boost::blank, T2 = boost::blank] void swap(T1& left, T2& right) ^ /opt/local/include/boost/variant/detail/move.hpp:44:13: note: candidate function [with T1 = boost::blank, T2 =boost::blank] inline void swap(T1& lhs, T2& rhs) In this case one could remove the Optional header, but in a larger project this is of course not a solution; a better solution seems to add an overload for swap taking two boost blanks. I feel this is a bug in Boost, can someone confirm and tell me where I should file the bug request? Finally I noticed due to the above error messages that boost::variant will never use variadic templates when you use Clang. For GCC it uses them (in C++11 mode), but for Clang it refuses. Why is this? Thanks, -Berteun

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[Context] Boost.Context ARM64 support
by mefyl 14 Jan '15

14 Jan '15

Hi, We currently use boost context on iOS, and as you may know Apple is making it mandatory for application to bundle a 64bits version starting February 1 (https://developer.apple.com/news/?id=10202014a) It is thus crucial for us - and anyone using Boost Context on iOS - to get a working ARM64 backend working. Looking at github, I see code has been contributed, but the build system still bounces to unsupported.hh when building with clang for ARM64. Is that code acutally working but not-yet-released, or is it still incomplete ? In the latter case, is anyone still working on it and do we have any rough idea of the delay before a working version get pushed ? Happy to read some ARM64 doc and contribute if it's in a stale state, of course. Cheers, -- Quentin "mefyl" Hocquet CTO @ infinit.io

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