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Boost 1.61.0 has been released
by Rene Rivera 19 May '16

19 May '16

Release 1.61.0 of the Boost C++ Libraries is now available. These open-source libraries work well with the C++ Standard Library, and are usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use. This release contains four new libraries and numerous enhancements and bug fixes for existing libraries. New Libraries * Compute: Parallel/GPU-computing library, from Kyle Lutz. * DLL: Library for comfortable work with DLL and DSO, from Renato Tegon Forti and Antony Polukhin * Hana: A modern C++ metaprogramming library, from Louis Dionne. * Metaparse: A library for generating compile time parsers parsing embedded DSL code as part of the C++ compilation process, from Abel Sinkovics. For details, including download links, see http://www.boost.org/users/news/version_1.61.0 You can also download directly from SourceForge: http://sourceforge.net/projects/boost/files/boost/1.61.0/ Tom Kent has made pre-built windows binaries, and they are available at: https://sourceforge.net/projects/boost/files/boost-binaries/1.61.0/ To install this release on your system, see http://www.boost.org/doc/libs/release/more/getting_started/index.html Thanks, --The Boost release team Vladimir Prus Rene Rivera Marshall Clow Eric Niebler Daniel James Beman Dawes

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DMARC and mailman
by James Sharpe 19 May '16

19 May '16

In June 2016 gmail is going to be changing its DMARC policy to reject any unaligned mail. This means that we will be seeing any mailing list responses from a gmail.com address to be considered spam by any mail server that enforces DMARC. For a while now yahoo.com has had this policy turned on which has meant that yahoo.com addresses have been considered spam. Mailman has released a workaround in version 2.1.18: https://www.mail-archive.com/mailman-users@python.org/msg64098.html The boost mailing list is currently on mailman 2.1.15. I'd strongly suggest that this should be updated as a matter of urgency else we'll find a lot of the conversations on this list will end up in the spam folder... Regards, James

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[boost::python] cannot concatenate 'str' and 'property' objects
by sergei nazarenko 19 May '16

19 May '16

Hello! I have just simple question. python code: a = A() bla = "lala" + a.pp *Traceback (most recent call last):TypeError: cannot concatenate 'str' and 'property' objects* Why it is not work? How make it is work? boost c++ code: #include <boost/python/module.hpp> #include <boost/python/def.hpp> #include <boost/python/class.hpp> #include <boost/python/init.hpp> class A { public: std::string pp; A(): pp("babla") {}; }; using namespace boost::python; BOOST_PYTHON_MODULE (test1) { class_<A> ("A") .def(py::init<>()) .add_property ("pp", &A::pp) ; } Thanks, Sergiy

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Documentation for Boost Range
by Christian Aichinger 19 May '16

19 May '16

Boost Range is a cool library, but it's sometimes hard to see how to actually use it: which headers to include, how to call it, what the return types are. To improve this situation, I wrote full, self-contained code examples for each function in Boost Range. They are available at: https://greek0.net/boost-range The examples also include links to the official docs and the into the library's source code, as well as a list of headers that give access to a specific function. I hope it's useful for other people as well. If you have any ideas for improvement, please let me know. Kind regards, Chris

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Blocking sockets on Windows
by William Riancho 18 May '16

18 May '16

Hello all, I try to implement a simple http server with blocking sockets on Windows. Basically, I have a simple server that just write data to a socket when a network connection occurs before exit. The problem is that the last "socket.send" as no effect if I don't delay the process exit. Writing to this socket is supposed to block until all the data as been written. I have tried to use the completion condition of write, to use the non_blocking method of the socket. I still get the same problem. Note that the problem doesn't occur on Linux. Here is the code: ``` #include <boost/asio.hpp> int main(int argc, char *argv[]) { char *address = "0.0.0.0"; char *port = "8180"; boost::asio::io_service io_service; boost::asio::ip::tcp::acceptor acceptor(io_service); boost::asio::ip::tcp::resolver resolver(io_service); boost::asio::ip::tcp::resolver::query query(address, port); boost::asio::ip::tcp::endpoint endpoint = *resolver.resolve(query); acceptor.open(endpoint.protocol()); acceptor.bind(endpoint); acceptor.listen(); boost::asio::ip::tcp::socket sock(io_service); acceptor.accept(sock); std::string body("Hello, World!"); sock.send(boost::asio::buffer(std::string("HTTP/1.1 200 OK\r\n"))); sock.send(boost::asio::buffer(std::string("Content-Length: ") + std::to_string(body.size()) + "\r\n\r\n")); sock.send(boost::asio::buffer(body)); Sleep(1000); // The body would not be sent without this return 0; } ```

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Review Wizard Report for May 2016
by Ronald Garcia 18 May '16

18 May '16

============================================== Review Wizard Status Report for May 2016 ============================================== News ==== 1. Boost 1.58 Released April 2015. New Libraries: Endian, Sort 2. Metaparse Library Accepted 3. Hana Library Accepted 4. DLL Library Accepted 5. Http Library Rejected 6. Boost 1.59 Released August 2015. New Libraries: Coroutine2, Convert 7. AFIO Library Reviewed 8. Fiber Library Conditionally Accepted 9. Boost 1.60 Released December 2015. New Libraries: Variadic Macro Data 10. Quaternions, Vectors, Matrices Accepted 11. Fit Library Rejected 11. Boost 1.61 Released May 2016. New Libraries: Compute, DLL, Metaparse, Hana 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 reviewed and await reports from their review managers: * AFIO - reviewed August 2015; review manager: Ahmed Charles. The following libraries have been accepted to Boost, but have not yet been integrated into Boost Git: * Contract - accepted September 2012; author: Lorenzo Caminiti. * Quaternions,Vectors,Matrices - accepted December 2015; author: Emil Dotchevski The following libraries have been accepted and submitted to Boost Git, but have not yet appeared in a release: * none The following libraries have been accepted provisionally to Boost, but have not been submitted for mini-review and full acceptance: * none 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) * Block Pointer (M) * Singularity (M) * Extended Complex Numbers (M) * Boost.Range Extensions * Nowide (M) * Array (M) * STL Extensions (M) * Countertree (M) * Process (M) * Application (M) * Edit Distance (M) * Mixin (M) * Dependency Injection (M) * Segmented Tree * Fiber ``(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. 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) 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 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) Segmented Tree -------------- :Author: Chris Clearwater :Download: http://rrsd.com/blincubator.com/bi_library/segmentedtreeseq-2/?gform_post_i… :Repository: http://github.com/det/segmented_tree :Documentation: https://det.github.io/segmented_tree :Review Manager: Glen Fernandes :Description: SegmentedTreeSeq is a sequence data structure like vector and deque that supports efficient random access insert and erase. It is implemented using B+Trees and has an emphasis on speed and a low memory overhead. Fiber ----- :Author: Oliver Kowalke :Download: https://github.com/olk/boost-fiber :Documentation: http://olk.github.io/libs/fiber/doc/html/ :Review Manager: Nat Goodspeed :Description: Boost.Fit is a header-only C++11/C++14 library that provides utilities for functions and function objects. Libraries under development =========================== See The Boost Library Incubator Project at http://blincubator.com for discussion of libraries currently under development.

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Memory deallocation concerning boost::bind, boost::asio and shared_ptr
by Norman Kradepohl 17 May '16

17 May '16

Hi there, my code is allocating memory and never freeing it, even though it should (at least in my opinion). The header looks like this: typedef boost::asio::ssl::stream<boost::asio::ip::tcp::socket> sslSocket_t; class Object { boost::asio::io_service ioService_; boost::asio::ip::tcp::acceptor acceptor_; boost::asio::ssl::context context_; void functionOne(); void functionTwo(shared_ptr<sslSocket_t>& sslSocket, const boost::system::error_code& error) } And my source like this: void Object::functionOne() { for (int i = 0; i < 10; i++) { shared_ptr<sslSocket_t> sslSocket(new sslSocket_t(ioService_, context_)); acceptor_.async_accept(sslSocket->lowest_layer(), boost::bind(&Object::functionTwo, this, sslSocket, boost::asio::placeholders::error)); } acceptor_.cancel(); boost::asio::io_service::work work(ioService_); ioService_.run(); } void functionTwo(shared_ptr<sslSocket_t>& sslSocket, const boost::system::error_code& err) { // Do nothing } So when i call *Object.functionOne()*, memory is getting allocated to the *Object.ioService_* object, in order to be able to call the bound asynchronous method. Then after the loop, all pending asynchronous actions on the acceptor are getting canceled. The appropriate handler is getting invoked as soon as *Object.ioService_.run()* is called (i've been testing that). BUT for some reason, the allocated memory does not get freed. I'm stuck on this problem for a while now, any hint or help would be really appreciated. Btw.: I'm working on debian and looking at "/proc/self/status" -> "VmRSS" to whatch the used memory.

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- Units presentation
by Roman Fratczak 17 May '16

17 May '16

Dears, How to "correctly" display an quantity units for "specific energy" in [kJ/kg] - always? Is there a method for preventing units simplification down to [m2/s2]? Regards Roman

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[proto] grammar to match operator in expression
by Igor R 16 May '16

16 May '16

Hi, Why the following grammar doesn't match dereference, and what's the correct way to do this? Thanks! ////////////////// #include <iostream> #include <boost/proto/proto.hpp> namespace proto = boost::proto; using proto::_; struct has_deref : proto::or_< proto::dereference<_>, proto::nary_expr<_, proto::vararg<has_deref>> > {}; template<class Expr> void test_expr(const Expr &e) { proto::display_expr(e); std::cout << "matches? " << std::boolalpha << proto::matches<Expr, has_deref>::value << std::endl; } int main() { test_expr(proto::lit(1) + *proto::lit(2)); }

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qx(3):
by Silviu P 16 May '16

16 May '16

http://www.granfoundation.org/hmmhjhm.php ***********************Neither a wise man or a _brave man lies down on the tracks of history to wait for the train of the future to run over him.Leana Fargo

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[Boost.Container] Problems in Solaris trying to use class flat_set
by dariomt＠gmail.com 12 May '16

12 May '16

Hi all, Trying to compile the following program is problematic with the Solaris compiler. $ cat kk.cpp #include <boost/container/flat_set.hpp> Yes, it is just one line #include'ing flat_set.hpp - with Boost 1.55.0 the compiler ICE's on me :( $ CC -Iboost/1_55_0 -features=extensions -library=stlport4 kk.cpp >> Assertion: (../lnk/v2mangler.cc, line 776) while processing boost/1_55_0/boost/container/detail/utilities.hpp at line 1036. - and with Boost 1.59.0 I have a compile error: $ CC -Iboost/1_59_0 -features=extensions -library=stlport4 kk.cpp "boost/1_59_0/boost/container/throw_exception.hpp", line 112: Error: Cannot cast from const char* to std::out_of_range. "boost/1_59_0/boost/container/throw_exception.hpp", line 128: Error: Cannot cast from const char* to std::length_error. "boost/1_59_0/boost/container/throw_exception.hpp", line 145: Error: Cannot cast from const char* to std::logic_error. "boost/1_59_0/boost/container/throw_exception.hpp", line 161: Error: Cannot cast from const char* to std::runtime_error. "boost/1_59_0/boost/container/detail/copy_move_algo.hpp", line 997: Error: type is not a member of boost::move_detail::enable_if_c<0, void>. 5 Error(s) detected. Compiler version: $ CC -V CC: Sun C++ 5.10 SunOS_i386 Patch 128229-32 2013/12/04 Any clues?

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Shared memory: private node allocator for a boost::unordered_map
by trafdev 12 May '16

12 May '16

Hello. I'm trying to use a private node allocator for an unordered_map placed in the shared memory: #include <boost/interprocess/managed_shared_memory.hpp> #include <boost/interprocess/containers/map.hpp> #include <boost/unordered_map.hpp> #include <boost/interprocess/allocators/allocator.hpp> #include <boost/interprocess/allocators/private_node_allocator.hpp> #include <functional> #include <utility> int main () { using namespace boost::interprocess; struct shm_remove { shm_remove() { shared_memory_object::remove("MySharedMemory"); } ~shm_remove(){ shared_memory_object::remove("MySharedMemory"); } } remover; managed_shared_memory segment (create_only ,"MySharedMemory" //segment name ,65536); //segment size in bytes typedef int KeyType; typedef float MappedType; typedef std::pair<const int, float> ValueType; typedef private_node_allocator<ValueType, managed_shared_memory::segment_manager> ShmemAllocator; typedef boost::unordered_map<KeyType, MappedType, boost::hash<KeyType>, std::equal_to<KeyType>, ShmemAllocator> MyMap; ShmemAllocator alloc_inst (segment.get_segment_manager()); MyMap *mymap = segment.construct<MyMap>("MyMap") //object name (3, boost::hash<KeyType>(), std::equal_to<KeyType>(), alloc_inst); for(int i = 0; i < 100; ++i){ mymap->insert(std::pair<const int, float>(i, (float)i)); } return 0; } It gives a compilation error: /usr/local/include/boost/unordered/detail/unique.hpp:30:43: error: no type named 'pointer' in 'boost::interprocess::private_node_allocator<boost::unordered::detail::unique_node<boost::interprocess::private_node_allocator<std::__1::pair<const int, float>, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0>, 0>, iset_index>, 64>, std::__1::pair<const int, float> >, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0>, 0>, iset_index>, 64>' A, unique_node<A, T> >::type::pointer node_pointer; What am I doing wrong?

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[boost.lockfree][spsc_queue] runtime sizing and producer's thread
by Sampath Tilakumara 12 May '16

12 May '16

Hi, Two questions on lockfree spsc_queue: 1. Can spsc_queue be dynamically (runtime) sized, and if so how do you correctly do it? * Creating a mpmc queue with size 0 (i.e. queue<T>(0)) creates a dynamically sizes mpmc queue, but doing the same for spsc queue doesn't. * creating a spsc queue with size 10 (i.e. queue<T>(10)) seems to create a fixed sized ring buffer since at high transfer rates, push fails, however the constructor code that takes the size asserts that it's runtime sized. explicit spsc_queue(size_type element_count): base_type(element_count) { BOOST_ASSERT(runtime_sized); } * documentation mentions lockfree::fixed_sized<> in policies, and can also be found in (mpmc) queue.hpp, but it doesn't seem to be in spsc_queue.hpp * all examples I could find on the internet (and documentation) was for fixed size or for mpmc dynamic, but not for spsc dynamic. 2. In a normal (spsc using) program the producer will be a single OS thread; however is it still safe to use on something like an actor framework or fiber framework? (i.e. you only have a single producer object, but it can actually be executed in different threads -- though strictly on one thread at any given time). for example in spsc_queue.hpp there's some code such as: bool push(T const & t, T * buffer, size_t max_size) { const size_t write_index = write_index_.load(memory_order_relaxed); // only written from push thread Refs on actors/fibers: https://en.wikipedia.org/wiki/Fiber_%28computer_science%29 https://en.wikipedia.org/wiki/Actor_model Thank you. Sampath Tilakumara

2 1

FindBoost.cmake does not check for include headers
by j.wuttke 11 May '16

11 May '16

As per cmake 3.5.1, FindBoost.cmake does not check for include headers. Therefore it will give false positives - if a Boost project that only consists of a header file is not installed - if only a libboost* is installed, but not the headers from the corresponding *-dev package. I raised this issue long ago on the cmake bug tracker, and recently again on the cmake mailing list, but got no response. Would perhaps somebody from the Boost community volunteer to look into this issue? Or has already looked into it and could tell us what the problem is?

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Fwd: [proto][variant] variant crashes proto expression
by Igor R 11 May '16

11 May '16

The following code is a slightly modified Proto calc2 example. Instead of doubles I use variant<int, double>, and the expression is just _1 = _2. This code triggers assertion in variant/detail/forced_return.hpp, so it looks like some variant instance gets messed up. It happens when the value returned from proto::eval(*this, ctx) is being copied. It can be reproduced both with MSVC and gcc, with Boost 1.60. Is there any workaround for this issue? Thanks. ////////////// #include <iostream> #include <boost/proto/proto_typeof.hpp> #include <boost/proto/core.hpp> #include <boost/proto/context.hpp> #include <boost/variant.hpp> namespace proto = boost::proto; using proto::_; typedef boost::variant<int, double> var_t; template<typename Expr> struct calculator_expression; // Tell proto how to generate expressions in the calculator_domain struct calculator_domain : proto::domain<proto::generator<calculator_expression> > {}; // Will be used to define the placeholders _1 and _2 template<int I> struct placeholder {}; // Define a calculator context, for evaluating arithmetic expressions // (This is as before, in calc1.cpp) struct calculator_context : proto::callable_context< calculator_context const > { // The values bound to the placeholders var_t d[2]; // The result of evaluating arithmetic expressions typedef var_t result_type; explicit calculator_context(const var_t &d1 = var_t(), const var_t &d2 = var_t()) { d[0] = d1; d[1] = d2; } // Handle the evaluation of the placeholder terminals template<int I> result_type operator ()(proto::tag::terminal, placeholder<I>) const { return d[ I - 1 ]; } }; // Wrap all calculator expressions in this type, which defines // operator () to evaluate the expression. template<typename Expr> struct calculator_expression : proto::extends<Expr, calculator_expression<Expr>, calculator_domain> { explicit calculator_expression(Expr const &expr = Expr()) : calculator_expression::proto_extends(expr) {} BOOST_PROTO_EXTENDS_USING_ASSIGN(calculator_expression<Expr>) // Override operator () to evaluate the expression var_t operator ()() const { calculator_context const ctx; return proto::eval(*this, ctx); } var_t operator ()(const var_t &d1) const { calculator_context const ctx(d1); return proto::eval(*this, ctx); } var_t operator ()(const var_t &d1, const var_t &d2) const { calculator_context const ctx(d1, d2); return proto::eval(*this, ctx); } }; // Define some placeholders (notice they're wrapped in calculator_expression<>) calculator_expression<proto::terminal< placeholder< 1 > >::type> const _1; calculator_expression<proto::terminal< placeholder< 2 > >::type> const _2; // Now, our arithmetic expressions are immediately executable function objects: int main() { BOOST_PROTO_AUTO(expr, _1 = _2); var_t a1(1), a2(2.5); expr(a1, a2); return 0; }

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openmpi with boost::log and some late endl
by Peter Vollmer 11 May '16

11 May '16

I'm working on some Linux systems and boost:log. More in detail: After replacing a handmade solution for logging with boost:log and running it with mpi on a single computer I can observe a strange behavior in console. Normally as i understand it, with autoflush turn on, after streaming a message into the logger it follows a flush followed by an endl and flush. At my scenario after streaming messages on different mpi processes, it seem that the system make a thread change right after flushing my message not after the endl flush. The missing automatic endl isn't lost it will be printed directly after or later but it will be printed. One indication that it has to be a thread change of the system is that an increase of the usable mpi processes increases the presents dramatically. For example on 4 core 8 thread system it occurs with 4 mpi processes something around 1 or 2 times, with 8 it occurs more than 20 times. Is there a solution to prevent this? Thanks Peter

1 0

[proto][spirit] parsing into proto expressions
by Igor R 11 May '16

11 May '16

Hi, Long story short: I would like to create proto expressions at run-time using spirit parsers. Would it be possible? More in details: I'd like to parse disassembler output, creating proto expression template for instruction and its operands. Lets assume we define proto expressions that would allow to express the following asm: "lea eax, [ebx + 2 * ecx]" like this: BOOST_PROTO_AUTO(lea_instr, eax = &*(ebx + 2 * ecx)); // registers and immediates are proto terminals Of course, we can't write such an expression in C++ code, because the actual operands get known after the asm string is parsed. So we can express any "lea" in the code (at compile-time) in a more general form, using placeholders: _1 = &_2; Then, when the parser matches "lea", we need to parse and create at run-time the actual operands, i.e. to substitute _1 with eax and _2 with *(ebx + 2 * ecx). I'd appreciate any pointer! Thanks.

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mpfr_float stack allocation
by Daniel Brake 10 May '16

10 May '16

Hi Boost Users, I use Boost.Multiprecision's wrappers for MPFR, particularly the boost::multiprecision::mpfr_float. I've had good success with this library and its types so far, enjoying performance gains because of expression templates, and easy access to mpfr and gmp for floats, ints, and rationals. However, in my complex number type, I am struggling with named real temporaries in arithmetic operators. I am looking for help with multiplication, and I can generalize to all other operations needing a real temporary later. Here's my current code for multiplication, implemented in terms of *=. /** Complex multiplication. uses a single temporary variable 1 temporary, 4 multiplications */ complex& operator*=(const complex & rhs) { mpfr_float re_cache(real_*rhs.real_ - imag_*rhs.imag_); // cache the real part of the result imag_ = real_*rhs.imag_ + imag_*rhs.real_; real_ = re_cache; return *this; } I am using the naive evaluation formula, for better or worse. But the particular method of evaluation doesn't matter to me right now, it's the temporary variable re_cache used to cache the real part is killing me. Profiling using Allinea, gprof, and Callgrind reveals that a significant percentage of time in the program is consumed creating and destroying re_cache, as well as other temporaries scattered throughout my code. In an effort to eliminate heap allocations, I first tried replacing my using mpfr_float = boost::multiprecision::number<boost::multiprecision::mpfr_float_backend<0,boost::multiprecision::allocate_dynamic>, boost::multiprecision::et_off>; with allocate_stack, just for these named temporary variables. However, the documentation <http://www.boost.org/doc/libs/1_60_0/libs/multiprecision/doc/html/boost_mul…> states that allocate_stack only works in fixed precision, so the 0 digits indicating variable precision should cause problems? I expected 0 digits to fail to compile, but compile it does. The conversion from the type with allocate_stack to allocate_dynamic is not provided by the = operator, so I can write re_cache.convert_to<mpfr_float_dynamic>(). But using variable precision with stack allocation appears to cause all sorts of problems. Everything depending on complex multiplication in my program breaks, indicated by massive failures in my test suite. Thus, I currently regard allocate_stack as a non-solution. My question fundamentally regards how to deal with re_cache and the *= operator for complex multiplication. Anyone have ideas on how to get rid of constant heap de/allocation of re_cache without inducing a ton more arithmetic? Using a static for it is not a solution, both because I anticipate multithreading in this application in the future, and the fact that precision will vary though the run, so I'd have to check the precision of re_cache on every evaluation. The C version of the program I am re-implementing used OpenMP for threads, and used a thread-id-indexed global for re_cache. That solution then forces OpenMP onto anyone wanting to use the complex class in multiple threads. Hence, I view this as a non-solution, too. Again, my initial thought was 'heap allocation is the problem here, so I'll use the stack allocated backend'. But variable precision doesn't appear to work with allocate_stack. And statics are no good. Any thoughts? Thanks for your time, Daniel Brake Postdoc University of Notre Dame Applied and Computational Math and Stats

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Re: [Boost-users] [boost] Boost 1.61.0 Release Candidate 2
by Marshall Clow 09 May '16

09 May '16

On Sat, May 7, 2016 at 4:31 AM, Vladimir Prus <vladimir.prus(a)gmail.com> wrote: > > The second release candidates for the 1.61.0 release are now available at: > > http://boost.cowic.de/rc/boost_1_61_0_rc2.zip > http://boost.cowic.de/rc/boost_1_61_0_rc2.7z > http://boost.cowic.de/rc/boost_1_61_0_rc2.tar.bz2 > http://boost.cowic.de/rc/boost_1_61_0_rc2.tar.gz > > The SHA256 checksums are as follows: > > fa1c34862b7ba8674ed6e064a14667a11830c6252f702d9458451834b74f7815 > boost_1_61_0_rc2.7z > a547bd06c2fd9a71ba1d169d9cf0339da7ebf4753849a8f7d6fdb8feee99b640 > boost_1_61_0_rc2.tar.bz2 > a77c7cc660ec02704c6884fbb20c552d52d60a18f26573c9cee0788bf00ed7e6 > boost_1_61_0_rc2.tar.gz > 02d420e6908016d4ac74dfc712eec7d9616a7fc0da78b0a1b5b937536b2e01e8 > boost_1_61_0_rc2.zip > > The changes relative to RC1 are MSVC fixes for signals2 and graph > libraries. > > As always, the release managers would appreciate it if you download > the candidate of your choice and give building it a try. Please report > both success and failure, and anything else that is noteworthy. > > I successfully built the .bz2 release with Apple's clang with C++03/11/14/1z. -- Marshall

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Boost ASIO steady_timer and date change
by Sabino Colonna 09 May '16

09 May '16

Hello, I'm using a steady_timer to perform an asynchronous wait in the following manner: boost::asio::io_service io_service; boost::asio::steady_timer my_timer(io_service); void onTimeout(const boost::system::error_code& e) { // Print something } ... my_timer.expires_from_now(std::chrono::seconds(600)); my_timer.async_wait(onTimeout); io_service.run(); If system 'date' does not change, everything is ok. But if I change 'date' by hand while the timer is running, it expires before 600 seconds (more or less after 5 minutes) and 'onTimeout' is called. With synchronous wait, all is ok. According to documentation, steady_timer should not be affected by time change. Which may be the problem? Thanks, Sabino

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Re: [Boost-users] Compiler limitation (MSVS 2015 update 2) or real error using boost::async?
by James Swift 06 May '16

06 May '16

Hi, in case anyone wants to play with the example I provided but doesn't have access to MSVC you can do so online here. http://rextester.com/BAX37541 kind regards, James

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converting to float128 from double
by Cooper, Bridgette R D 04 May '16

04 May '16

Hi, I have a function that takes as an argument a vector of doubles and tries to convert it to a vector of float128. When I accumulate the values in the float128 vector it looks like it does double additions and only casts up at the last step. The initial vector is defined as const std::vector<double> The float128 vector is defined as std::vector<float128> epoint(num) And I try to do the casting (inside a loop) via: epoint.at(i)=(float128(e8.at(i))); If I do the accumulation on the original vector with no casting into a float128, I get the same as accumulating the vector that should be of float128 type. How should I be doing the casting? Thanks,

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Compiler limitation (MSVS 2015 update 2) or real error using boost::async?
by James Swift 04 May '16

04 May '16

Hi, I'm getting an error with the following code only with Visual C++. (VS 2015 update 2. I also tried preview of VS 15 but it's the same) Clang and GCC are OK with this but perhaps VS is just more strict but correct? The error is deep in boost internals and I can't work out which object is move only and/or has it's copy constructor deleted or if it's true at all! Any help greatly appreciated. kind regards, James Swift --------------------------------- #define BOOST_THREAD_PROVIDES_FUTURE #define BOOST_THREAD_PROVIDES_FUTURE_CONTINUATION #define BOOST_THREAD_PROVIDES_EXECUTORS #include <boost/thread/future.hpp> class TestEx { public: void submit(std::function<void()>) { } bool try_executing_one() { return false; } bool closed() { return false; } void close() { } }; int main() { TestEx tex; boost::async( tex, [](){}); return 0; } ----------------------------------- 1>------ Build started: Project: BoostFuture, Configuration: Debug Win32 ------ 1> BoostFuture.cpp 1>c:\users\james\documents\visual studio 2015\projects\boostfuture\boostfuture\boost_1_60\boost\thread\future.hpp(3801): error C2280: 'boost::detail::invoker<main::<lambda_4383c995bef90b35d4f40a119c795fc2>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>::invoker(const boost::detail::invoker<main::<lambda_4383c995bef90b35d4f40a119c795fc2>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type> &)': attempting to reference a deleted function 1> c:\users\james\documents\visual studio 2015\projects\boostfuture\boostfuture\boost_1_60\boost\thread\detail\invoker.hpp(731): note: compiler has generated 'boost::detail::invoker<main::<lambda_4383c995bef90b35d4f40a119c795fc2>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>::invoker' here 1> c:\users\james\documents\visual studio 2015\projects\boostfuture\boostfuture\boost_1_60\boost\thread\future.hpp(3800): note: while compiling class template member function 'boost::detail::shared_state_nullary_task<Rp,Cont>::shared_state_nullary_task(const boost::detail::shared_state_nullary_task<Rp,Cont> &)' 1> with 1> [ 1> Rp=Rp 1> ] 1> c:\program files (x86)\microsoft visual studio 14.0\vc\include\xutility(287): note: see reference to function template instantiation 'boost::detail::shared_state_nullary_task<Rp,Cont>::shared_state_nullary_task(const boost::detail::shared_state_nullary_task<Rp,Cont> &)' being compiled 1> with 1> [ 1> Rp=Rp 1> ] 1> c:\users\james\documents\visual studio 2015\projects\boostfuture\boostfuture\boost_1_60\boost\thread\future.hpp(3858): note: see reference to class template instantiation 'boost::detail::shared_state_nullary_task<Rp,Cont>' being compiled 1> with 1> [ 1> Rp=Rp 1> ] 1> c:\users\james\documents\visual studio 2015\projects\boostfuture\boostfuture\boost_1_60\boost\thread\future.hpp(3873): note: see reference to function template instantiation 'void boost::detail::future_executor_shared_state<Rp>::init<T,Executor>(Executor &,Fp &&)' being compiled 1> with 1> [ 1> Rp=Rp, 1> T=boost::detail::invoker<main::<lambda_4383c995bef90b35d4f40a119c795fc2>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>, 1> Executor=TestEx, 1> Fp=boost::detail::invoker<main::<lambda_4383c995bef90b35d4f40a119c795fc2>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type> 1> ] 1> c:\users\james\documents\visual studio 2015\projects\boostfuture\boostfuture\boost_1_60\boost\thread\future.hpp(3873): note: see reference to function template instantiation 'void boost::detail::future_executor_shared_state<Rp>::init<T,Executor>(Executor &,Fp &&)' being compiled 1> with 1> [ 1> Rp=Rp, 1> T=boost::detail::invoker<main::<lambda_4383c995bef90b35d4f40a119c795fc2>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>, 1> Executor=TestEx, 1> Fp=boost::detail::invoker<main::<lambda_4383c995bef90b35d4f40a119c795fc2>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type> 1> ] 1> c:\users\james\documents\visual studio 2015\projects\boostfuture\boostfuture\boost_1_60\boost\thread\future.hpp(3964): note: see reference to function template instantiation 'boost::future<void> boost::detail::make_future_executor_shared_state<Rp,boost::detail::invoker<main::<lambda_4383c995bef90b35d4f40a119c795fc2>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>,Executor>(Executor &,Fp &&)' being compiled 1> with 1> [ 1> Executor=TestEx, 1> Fp=boost::detail::invoker<main::<lambda_4383c995bef90b35d4f40a119c795fc2>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type> 1> ] 1> c:\users\james\documents\visual studio 2015\projects\boostfuture\boostfuture\boostfuture.cpp(34): note: see reference to function template instantiation 'boost::future<void> boost::async<TestEx,main::<lambda_4383c995bef90b35d4f40a119c795fc2>>(Executor &,F &&)' being compiled 1> with 1> [ 1> Executor=TestEx, 1> F=main::<lambda_4383c995bef90b35d4f40a119c795fc2> 1> ] ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

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udp::endpoint - port change
by Alexander Carôt 04 May '16

04 May '16

Hello all, probably trivial but I am currently stuck with this: I create a UDP endpoint via udp::resolver::query query(udp::v4(),IP,port); destinationEndpoint = new udp::endpoint(*resolver.resolve(query)); but after the creation I want to change the port without deleting and recreating it with different parameters. How can I do this ? Thanks in advance, best Alex

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Re: [Boost-users] Extending boost graph edge class
by Rafael Gasperetti 03 May '16

03 May '16

Hi, The third option fit in my case. I haver a class that I need to be the edge of the graph, and i have another one that I need to be the vertex. Using this way, My classes Can be used inside the graph to calculate distance, scc, etc. Thanks,Rafael -------- Mensagem original -------- De : Daniel Hofmann <daniel(a)trvx.org> Data: 03/05/2016 19:23 (GMT-03:00) Para: boost-users(a)lists.boost.org Assunto: Re: [Boost-users] Extending boost graph edge class Can you elaborate on "extend the edge class"? Here are some possible interpretations: 1/ You want to optimize the memory consumption for large graphs. The edges and vertices still fit into uint32_t: using graph_t = compressed_sparse_row_graph<directedS, no_property, no_property, no_property, uint32_t /* Vertex */, uint32_t /* EdgeIndex */>; 2/ You want to store arbitrary metadata on your edges and retrieve this edge data based on your graph and a specific edge descriptor: struct edge_data_t { int distance = 0; }; using graph_t = compressed_sparse_row_graph<directedS, no_property, edge_data_t>; // .. auto duration = [&graph](auto edge) { return graph[edge].duration; }; auto total = accumulate(edges(graph) | transformed(duration), 0); This example is using "bundled properties". There is also the possibility to store edge data external to the graph and not couple the edge data's lifetime with the graph (e.g. if you need edge weights for a particular algorithm in your use-case). 3/ You want to provide your own graph representation and make it a model for the BGL graph concepts: http://www.boost.org/doc/libs/1_60_0/libs/graph/doc/leda_conversion.html http://www.boost.org/doc/libs/1_60_0/libs/graph/doc/graph_concepts.html Here are some more BGL examples that should get you started: https://github.com/daniel-j-h/cppnow2016 Cheers, Daniel J H On 05/03/2016 08:37 AM, Rafael Gasperetti wrote: > > > Hi, > My name is Rafael and I need to extend the edge class of de graph part > of the boost lib, but I always find problems trying to do this. Can you > help me with examples and explanations about how to do this? > I read a lotação of places trying to do this but no help was found, > please help me. > > Thanks a lot, > Rafael > > > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users > _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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