June 2013 - Boost - lists.boost.org

A GUI Library
by jinhao 09 Nov '17

09 Nov '17

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

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bad include guards
by Steven Watanabe 26 Jan '17

26 Jan '17

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

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Arguing about names in Boost libraries
by Edward Diener 06 May '15

06 May '15

What is wrong with the people commenting on libraries for Boost who are so concerned about the names being used ? We are talking only about C++ identifiers and yet there are now endless discussions where people disagree on names or argue that some name is not what they want or that they like some other name, with a list of names that they find adequate. This is irrelevant. There is something mentally wrong about all those peoples spending endless amounts of time around this issue. I notice this does not happen nowadays for just one library but for ever single library, or proposed library, which is mentioned on this mailing list. Is this the way all of you people actually work in your daily jobs, or on your own projects, spending hours and days arguing with others about C++ identifiers for every little thing ? Are you not aware of the absurdity of your endless remarks ? Grow up ! Surely there are better things to do than carry on endlessly about some name, that is should be x or y or z or some other inane preferable list. It's time for somebody to say this, so I will do it. A C++ identifier name, as long as it is vaguely about what the functionality entails, is perfectly adequate. It does not have to satisfy everyone in the universe. Period !

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IDE for developing Boost
by Jens Müller 20 Dec '14

20 Dec '14

Hi, I am looking for recommendations for developing Boost, especially code in the graph library. At work, most developers (not for Boost, for some commercial software), most developers are using Eclipse. This works quite fine as soon as it has properly auto-discovered include paths etc. But before fiddling around with Eclipse to get all the settings right, I'd wanted to to ask for your recommendations. And maybe there are already settings available to make it "just work", at least initially. Cheers, Jens

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Is there any interest in a library for actor programming?
by Charousset, Dominik 28 May '14

28 May '14

Hi, is there any interest in a library for actor programming? The library we've developed is a C++11 open source library named "libcppa". It is currently released under LGPL2, but re-releasing the library under the boost license is not an issue. You'll find all important links and ressources either under http://libcppa.org or on the GitHub project page: https://github.com/Neverlord/libcppa, including a user manual as HTML or PDF. We've also submitted a paper to the C++Now conference. What is actor programming? For those of you who aren't yet familiar with the actor model: actors basically represent tasks or services that communicate via message passing. In libcppa, actors are very lightweight (you can spawn literally millions of them) and scheduled cooperatively using a thread pool (although actors are allowed to opt-out of the cooperative scheduling). Some of the main strengths of this programming paradigm are: (1) network transparency, (2) race conditions are avoided by design, (3) a strong failure model that enables developers to build reliable distributed systems, and (4) the actor model addresses both concurrency (multiple actors on one host) and distribution (any number of actors on any number of hosts). Here's the classical hello world example: ---------------------------------------------------------------------------------- #include <string> #include <iostream> #include "cppa/cppa.hpp" using namespace std; using namespace cppa; void mirror() { // wait for messages become ( // invoke this lambda expression if we receive a string on_arg_match >> [](const string& what) { // prints "Hello World!" via aout (thread-safe cout wrapper) aout << what << endl; // replies "!dlroW olleH" reply(string(what.rbegin(), what.rend())); // terminates this actor ('become' otherwise loops forever) self->quit(); } ); } void hello_world(const actor_ptr& buddy) { // send "Hello World!" to our buddy ... sync_send(buddy, "Hello World!").then( // ... and wait for a response on_arg_match >> [](const string& what) { // prints "!dlroW olleH" aout << what << endl; } ); } int main() { // create a new actor that calls 'mirror()' auto mirror_actor = spawn(mirror); // create another actor that calls 'hello_world(mirror_actor)' spawn(hello_world, mirror_actor); // wait until all other actors we have spawned are done await_all_others_done(); // run cleanup code before exiting main shutdown(); } ---------------------------------------------------------------------------------- A message is simply a tuple of values that is pattern matched at the receiver. For example, " on_arg_match >> [](const string& what) {...}" defines a message handler that is called whenever a tuple with one single string element arrives. "on_arg_match" simply defines a pattern that matches the signature of the given lambda. Please have a look at the examples folder on GitHub (https://github.com/Neverlord/libcppa/tree/master/examples) or at the user manual (http://neverlord.github.io/libcppa/manual/) if you want to see more examples. Best regards, Dominik Charousset

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required toolsets
by Steven Watanabe 15 May '14

15 May '14

AMDG The list of required toolsets in explicit-failures-markup.xml is out-dated. Therefore, if no one objects, I propose setting it to the following: msvc-10.0, msvc-11.0, gcc-4.6, gcc-4.7, clang-darwin-11, clang-darwin-4.2.1, clang-linux-3.1, clang-linux-3.2, gcc-mingw-4.7, gcc-mingw-4.6 (two releases of each major compiler that appears in both the trunk and release regression tests) The sole effect of this is to determine which toolsets appear in the issues list: http://www.boost.org/development/tests/trunk/developer/issues.html In Christ, Steven Watanabe

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Why no non-null smart pointers?
by Ross MacGregor 29 Apr '14

29 Apr '14

I just created a very small smart pointer libary for our project. It will contain two types of shared pointers: SharedHandle and NullableSharedHandle. SharedHandle will be a shared pointer that cannot be null by ensuring a non-null construction while NullableSharedHandle will basically be a typedef for boost::shared_ptr. I firmly believe that code can be made more reliable by minimizing the use of nullable pointers. To this end, I think it is important that we start using non-null pointer types. Ideally the compiler would be able to understand a non-null pointer and catch bugs at compile time, but I think we can still improve things with a few runtime checks. If we make sure that a shared pointer is constructed with a non-null pointer and ban any reset() type methods, we guarentee that it points to something. This can be beneficial for the following reasons: 1. Any function that uses this type will no longer be burdened with precondition checks to make sure variables of this type are not null. 2. It's type is simply more explicit and better explains its function. 3. Moving the non-null check to the creation phase will reduce the possibility of encountering null pointer exceptions at runtime (assuming there are many more pointer references than constructor calls). So my little pointer library seems to make a lot of sense, but if so why hasn't this simple smart pointer variation made it into boost yet? Has this been discussed somewhere already? My search on non-null smart pointers is not revealing much discussion on the topic. Regards, Ross

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boost::optional -- updates for C++11 move semantics
by Diggory Hardy 10 Apr '14

10 Apr '14

Dear list, I wanted something like boost::optional, but with support for move- construction/assignment, so I went ahead and had a go at patching it. Attached is based on boost 1.49 (Ubuntu package). Could someone please review? I've not contributed to boost before. The changes at least aren't too complicated, but: 1) I'm not entirely sure if the move constructor (line 636) and swap function (line 1046) are implemented in the best way (also see line 279), 2) and I have no idea how is_[not_]reference_tag (line 486) works. 3) There should maybe also be a unit test. Of course, I am happy for my contributions to be published under the boost licence. Regards, Diggory

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Interest in Base2/16/32/64 Encoding Library?
by Thomas Kemmer 27 Jan '14

27 Jan '14

Dear Boost Developers, I would like to know if there is interest in incorporating a generic Base2/16/32/64 encoding library into Boost. I am the author of such a libray, hosted at http://code.google.com/p/stlencoders/ and would be willing to contribute and make the effort of "Boostifying" it, if the Boost community is interested in such a thing. There have been several suggestions for a Base64 encoding library on this mailing list in the past. Most of them have been dismissed, since Boost already provides a Base64 implementation with Boost.Serialization's "Dataflow Iterators". Though I appreciate the dataflow iterator's design, from personal experience I think that for the basic task of encoding/decoding, a higher-level interface, e.g. one that takes padding and intermittent whitespace (MIME) into account, would benefit many developers. Currently, the stlencoders library - implements the Base16, Base32 and Base64 encoding schemes as defined in RFC 4648. Base2, i.e. binary encoding, is also supported. - implements encoding and decoding operations as generic algorithms that operate on STL-style iterators - supports different encoding alphabets using custom traits classes - supports different character types - lets the user define if/which non-alphabet characters should be ignored via predicates - provides reasonable performance that matches most "plain C" implementations stlencoders is currently designed as a stand-alone library with no dependencies on Boost (or anything but C++03); it would therefore take some effort and guidance from the community to properly integrate it with the rest of Boost. I would therefore appreciate any feedback regarding your interest in this. Kind Regards, Thomas

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C++03 and C++11 ABI compatibility for compiled libraries
by Andrey Semashev 24 Jan '14

24 Jan '14

Hi, I would like to raise the issue of binary compatibility of compiled Boost libraries between C++03 and C++11. I faced this problem with gcc on Linux, but other compilers and platforms may be affected as well. To summarize the problem: * Most, if not all Linux distributions build packages in C++03 mode. This is also the default in gcc. * Some Boost libraries conditionally use C++11 features in their binary interfaces (see [1] as an example). This makes C++03 and C++11 versions of the library binary incompatible. * Given that, users are unable to use C++11 in their code that uses Boost because of linker failures. I don't have the complete list of the offending C++11 features that break ABI, but it would seem that at least scoped enums and rvalue references are among them. Are there any more? I would like to hear opinions on the possible course of action to tackle this problem. Currently, I see 2 choices: 1. Avoid using C++11 features in binary interfaces. This may also mean avoiding STL types in binary interfaces, if they differ between C++03 and C++11 (I didn't verify that). This is my suggested hotfix solution for Boost.Filesystem [1] and the approach I took in Boost.Log. Obviously, this cripples code and error prone, but it keeps a single binary that can be used from any flavor of C++ on the user's side. 2. Compile different versions of Boost libraries, for each supported C++ version. The C++ version should be encoded into the library file names, so that different versions can coexist. This would require changes in Boost.Build and autolinking support code, but I think this would be a better long-term solution. Opinions? [1] https://svn.boost.org/trac/boost/ticket/6779

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[Macro]Test Case grouping using Traits
by Hemanth Choudary M V (RBEI/ETA1) 13 Jan '14

13 Jan '14

Hello, I have observed that in native unit test framework(c++), there is an option to group test cases using attributes which are reflected as traits in the Test Explorer window in MS VS2012. Following is a an example of the same: BEGIN_TEST_METHOD_ATTRIBUTE(TestMethod3) TEST_OWNER(L"SuperMan") TEST_PRIORITY(2) TEST_METHOD_ATTRIBUTE(L"Category",L"Slow") END_TEST_METHOD_ATTRIBUTE() TEST_METHOD(TestMethod3) { Assert::AreEqual(2,6); } How can this be achieved via Boost Unit Test Library? Are there macros to achieve the same? Mit freundlichen Grüßen / Best Regards, Hemanth Choudary MV RBEI/ETA1

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[filesystem] fix recur_dir_itr_imp::increment(system::error_code* ec) in 1.54.0
by claudio.bley＠gmail.com 19 Dec '13

19 Dec '13

Hi. What's happening to the filesystem library? It seems there's no progress on any tickets in the bug tracker? Referring to https://svn.boost.org/trac/boost/ticket/6821#comment:5 Could we get this fix into 1.54.0, please? BTW, sorry for any confusion - I "managed" to comment on the wrong ticket... https://svn.boost.org/trac/boost/ticket/5403 would've been more appropriate, I guess. Claudio -- Claudio

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RFC: edit_distance / edit_alignment library
by Erik Erlandson 18 Dec '13

18 Dec '13

Boost Community, I cooked up a library that provides a pair of functions: edit_distance() and edit_alignment(). The library currently lives here: https://github.com/erikerlandson/edit_distance Some short example programs are here: https://github.com/erikerlandson/edit_distance/tree/master/examples A few example expressions: // the edit distance (aka levenshtein distance) unsigned dist = edit_distance("abc", "bcd"); // using a custom cost function for insertion, deletion, substitution unsigned dist = edit_distance("abc", "bcd", custom_cost_function()); // accepts arbitrary sequences, ranges, range adaptors unsigned dist = edit_distance(as_vector("abc"), as_list("bcd") | boost::adaptors::reversed); // obtain the edit distance and the list of the edit operation codes (in output iterator) unsigned dist = edit_alignment("abc", "bcd", std::ostream_iterator<edit_opcode>(std::cout, "")).second; // adaptors to add edit operation costs and sequence elements to the edit operation output unsigned dist = acquire<elements>(acquire<costs>(edit_alignment))("abc", "bcd", std::ostream_iterator<boost::tuple<edit_opcode, unsigned, char, char> >(std::cout, "")).second; I'm interested in community feedback on whether these would be a useful addition to boost::algorithms. I envision these as the first additions to an eventually-larger library of other kinds of string distances, dynamic programming, and other algorithms for sequence alignment.

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[tweener] Doxygen documentation issues
by Julien Jorge 05 Nov '13

05 Nov '13

Hi, I am writing the documentation of Boost.Tweener and I encounter various difficulties. One of them is the generation of the class documentation with doxygen. It seems that it cannot extract the class and member documentation from .ipp files. I like to document the methods of my classes near the implementation. In Boost.Tweener, most of the class documentation is then in the .ipp files and I have written the following lines in the Jamfile.v2: import quickbook ; using boostbook ; using doxygen ; doxygen reference : [ glob ../../../boost/tweener/*.hpp ] [ glob ../../../boost/tweener/detail/*.hpp ] [ glob ../../../boost/tweener/detail/impl/*.ipp ] [ glob ../../../boost/tweener/detail/impl/easing/*.ipp ] [ glob ../../../boost/tweener/easing/*.hpp ] But when I try to build the documentation, I have the following error: boost_1_52_0/tools/build/v2/build/generators.jam:1085: in ensure-type from module generators error: target { ../../../boost/tweener/detail/impl/tweener_group.ipp. } has no type Moreover, if I remove the ipp files, the generation of the documentation does not fail but the doxygen documentation is not extracted, except for the private members. So, how can I also disable the extraction of the private members in the documentation? You can check the Jamfile.v2 in the git repository of the project: http://libclaw.git.sourceforge.net/git/gitweb.cgi?p=libclaw/boost-tweener;a… Regards, Julien

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[mpl] integral_c [type_traits] integral_constant limits
by vicente.botet 21 Oct '13

21 Oct '13

Hi, I was testing Boost.Ratio with gcc-4.6 c++0x and I get some compile errors when instantiating std::cout << boost::mpl::integral_c< boost::intmax_t, boost::integer_traits<boost::intmax_t>::const_max >::value ; ..\..\..\../boost/mpl/aux_/integral_wrapper.hpp: In instantiation of 'mpl_::integral_c<long long int, 0x7fffffffffffffffll>': ratio_io\ratio_io.pass.cpp:24:6: instantiated from here ..\..\..\../boost/mpl/aux_/integral_wrapper.hpp:72:96: warning: integer overflow in expression [-Woverflow] ..\..\..\../boost/mpl/aux_/integral_wrapper.hpp:72:96: error: '-0x8000000000000000ll' is not a valid template argument for type 'long long int' because it is a non-constant expression ..\..\..\../boost/mpl/aux_/integral_wrapper.hpp:72:96: error: '-0x8000000000000000ll' is not a constant expression integral_wrapper.hpp:72 contains typedef AUX_WRAPPER_INST( BOOST_MPL_AUX_STATIC_CAST(AUX_WRAPPER_VALUE_TYPE, (value + 1)) ) next; The same line pass with gcc-4.6, gcc-4.5 and gcc-4.5 c++0x with just a warning. ..\..\..\../boost/mpl/aux_/integral_wrapper.hpp: In instantiation of 'mpl_::integral_c<long long int, 0x7fffffffffffffffll>': ratio_io\ratio_io.pass.cpp:23:6: instantiated from here ..\..\..\../boost/mpl/aux_/integral_wrapper.hpp:72:96: warning: integer overflow in expression [-Woverflow] integral_c is by integral_constant, but integral_constant doesn't needs next a prior types. This means that with the current implementation we can not use integral_constant with the max value of the type. Do you think this is a bug in integral_constant? Best, _____________________ Vicente Juan Botet Escribá http://viboes.blogspot.com/

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[accumulators] Help understanding implementation of weighted accumulators
by Gabriel Redner 02 Oct '13

02 Oct '13

Hi folks, I am trying to implement a weighted accumulator, but I'm having trouble understanding a few things about the existing ones. Looking at the implementation of weighted_sum, I see (weighted_sum.hpp:37): template<typename Args> weighted_sum_impl(Args const &args) : weighted_sum_( args[parameter::keyword<Tag>::get() | Sample()] * numeric::one<Weight>::value ) { } My questions are: - It's taking the first sample from the args and multiplying it by a weight of 1. Isn't this wrong - ignoring the real weight of this sample? Shouldn't this produce incorrect results? - I've never understood anyways how there can be an initial argument during construction of the accumulator. I haven't found any explanation in the docs beyond "Maybe there is an initial value in the argument pack". Maybe? How? Probably more questions later. Thanks, -Gabe

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[scope_exit] D-style scope(failure) and scope(success) in C++
by Evgeny Panasyuk 30 Sep '13

30 Sep '13

Hello all, D language has scope(exit), scope(success) and scope(failure) features - http://dlang.org/statement.html#ScopeGuardStatement : "... scope(exit) executes NonEmptyOrScopeBlockStatement when the scope exits normally or when it exits due to exception unwinding. scope(failure) executes NonEmptyOrScopeBlockStatement when the scope exits due to exception unwinding. scope(success) executes NonEmptyOrScopeBlockStatement when the scope exits normally. ..." Andrei Alexandrescu describes some of uses cases for scope(exit), scope(success), scope(failure) at his recent talk : http://channel9.msdn.com/Events/Lang-NEXT/Lang-NEXT-2012/Three-Unlikely-Suc… There is Boost.ScopeExit library which emulates D's scope(exit) via BOOST_SCOPE_EXIT macro, but there are no analogues for D's scope(failure) and scope(success). Current alternative for these features is ScopeGuard idiom ( http://en.wikibooks.org/wiki/More_C%2B%2B_Idioms/Scope_Guard , http://www.drdobbs.com/cpp/generic-change-the-way-you-write-excepti/1844037… ). Boost.ScopeExit library itself suggests to use ScopeGuard - http://www.boost.org/doc/libs/1_51_0/libs/scope_exit/doc/html/scope_exit/al… : " Boost.ScopeExit is similar to scope(exit) feature built into the D programming language. A curious reader may notice that the library does not implement scope(success) and scope(failure) of the D language. Unfortunately, these are not possible in C++ because failure or success conditions cannot be determined by calling std::uncaught_exception (see Guru of the Week #47 for details about std::uncaught_exception and if it has any good use at all). However, this is not a big problem because these two D's constructs can be expressed in terms of scope(exit) and a bool commit variable (similarly to some examples presented in the Tutorial section). " I have made small library ( https://github.com/panaseleus/stack_unwinding#d-style-scope-guardsactions ) which supplies primitives (class unwinding_indicator, UNWINDING_AWARE_DESTRUCTOR macro) to determining when object destructor is called due to stack-unwinding or due to normal scope leaving. Currently it is implemented on top of platform-specific implementation of uncaught_exception_count function and tested on: {MSVC2005, MSVC2008, MSVC2010, MSVC2012, GCC4.1.2, GCC4.4.6, Clang3.2}x{x32, x64}x{default settings}. uncaught_exception_count is a function similar to std::uncaught_exception from standard library, but instead of boolean result it returns unsigned int showing current count of uncaught exceptions. Such primitives allow us to implement scope(success) and scope(failure) features in C++. I have made several proof-of-concepts: * https://github.com/panaseleus/stack_unwinding/blob/master/examples/scope_ac… * https://github.com/panaseleus/stack_unwinding/blob/master/examples/example_… * https://github.com/panaseleus/stack_unwinding/blob/master/examples/scope_gu… * https://github.com/panaseleus/stack_unwinding/blob/master/examples/boost_sc… boost_scopes.cpp example shows usage of BOOST_SCOPE_FAILURE and BOOST_SCOPE_SUCCESS: try { cout << "Case #1: stack unwinding" << endl; BOOST_SCOPE_EXIT(void) { cout << "exit" << endl; } BOOST_SCOPE_EXIT_END BOOST_SCOPE_FAILURE(void) { cout << "failure" << endl; } BOOST_SCOPE_FAILURE_END BOOST_SCOPE_SUCCESS(void) { cout << "success" << endl; } BOOST_SCOPE_SUCCESS_END throw 1; } catch(int){} { cout << "Case #2: normal exit" << endl; BOOST_SCOPE_EXIT(void) { cout << "exit" << endl; } BOOST_SCOPE_EXIT_END BOOST_SCOPE_FAILURE(void) { cout << "failure" << endl; } BOOST_SCOPE_FAILURE_END BOOST_SCOPE_SUCCESS(void) { cout << "success" << endl; } BOOST_SCOPE_SUCCESS_END } Output is: " Case #1: stack unwinding failure exit Case #2: normal exit success exit " Currently BOOST_SCOPE_FAILURE and BOOST_SCOPE_SUCCESS are implemented based on boost_1_51_0/boost/scope_exit.hpp by copy-paste and replace (just for proof-or-concept, of course it is possible solution with much less duplication). Semantically meaningful changes can be viewed as diff at https://github.com/panaseleus/stack_unwinding/commit/d5513404323490ea99d9b6… Before posting here, I made posts on several C++ forums, but unfortunately get only a few feedbacks regarding ScopeFailure and ScopeSuccess. What do you think? Thank you. P.S. Related discussion: http://lists.boost.org/Archives/boost/2010/09/171051.php Best Regards, Evgeny Panasyuk

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[thread] synchronized_value: value and move semantics
by Vicente J. Botet Escriba 24 Sep '13

24 Sep '13

Hi, boost::synchronized_value (not released yet [1][2][3]) is based on [4]. See below part of this paper adapted to the Boost.Thread interface. Currently boost::synchronized_value is in addition Copyable and Swappable. I was wondering if it is worth adding value and move semantics to synchronized_value. Making it EqualityComparable, LessThanComparable and Movable if the underlying type satisfy these requirements will allow to store them on a Boost.Container/C++11 container. Do you see something completely wrong with this addition? Has some of you had a need for this? Could you share the context? Best, Vicente [1] https://svn.boost.org/svn/boost/trunk/boost/thread/synchronized_value.hpp [2] https://svn.boost.org/svn/boost/trunk/libs/thread/example/synchronized_valu… [3] https://svn.boost.org/svn/boost/trunk/libs/thread/example/synchronized_pers… [4] "Enforcing Correct Mutex Usage with Synchronized Values" by Anthony Williams http://www.drdobbs.com/cpp/enforcing-correct-mutex-usage-with-synch/2252002… ------------- [section The Problem with Mutexes] The key problem with protecting shared data with a mutex is that there is no easy way to associate the mutex with the data. It is thus relatively easy to accidentally write code that fails to lock the right mutex - or even locks the wrong mutex - and the compiler will not help you. std::mutex m1; int value1; std::mutex m2; int value2; int readValue1() { boost::lock_guard<boost::mutex> lk(m1); return value1; } int readValue2() { boost::lock_guard<boost::mutex> lk(m1); // oops: wrong mutex return value2; } Moreover, managing the mutex lock also clutters the source code, making it harder to see what is really going on. The use of synchronized_value solves both these problems - the mutex is intimately tied to the value, so you cannot access it without a lock, and yet access semantics are still straightforward. For simple accesses, synchronized_value behaves like a pointer-to-T; for example: boost::synchronized_value<std::string> value3; std::string readValue3() { return *value3; } void setValue3(std::string const& newVal) { *value3=newVal; } void appendToValue3(std::string const& extra) { value3->append(extra); } Both forms of pointer dereference return a proxy object rather than a real reference, to ensure that the lock on the mutex is held across the assignment or method call, but this is transparent to the user. [endsect] [/The Problem with Mutexes] [section Beyond Simple Accesses] The pointer-like semantics work very well for simple accesses such as assignment and calls to member functions. However, sometimes you need to perform an operation that requires multiple accesses under protection of the same lock, and that's what the synchronize() method provides. By calling synchronize() you obtain an strict_lock_ptr object that holds a lock on the mutex protecting the data, and which can be used to access the protected data. The lock is held until the strict_lock_ptr object is destroyed, so you can safely perform multi-part operations. The strict_lock_ptr object also acts as a pointer-to-T, just like synchronized_value does, but this time the lock is already held. For example, the following function adds a trailing slash to a path held in a synchronized_value. The use of the strict_lock_ptr object ensures that the string hasn't changed in between the query and the update. void addTrailingSlashIfMissing(boost::synchronized_value<std::string> & path) { boost::strict_lock_ptr<std::string> u=path.synchronize(); if(u->empty() || (*u->rbegin()!='/')) { *u+='/'; } } [endsect] [/Beyond Simple Accesses] [section Operations Across Multiple Objects] Though synchronized_value works very well for protecting a single object of type T, nothing that we've seen so far solves the problem of operations that require atomic access to multiple objects unless those objects can be combined within a single structure protected by a single mutex. One way to protect access to two synchronized_value objects is to construct a strict_lock_ptr for each object and use those to access the respective protected values; for instance: synchronized_value<std::queue<MessageType> > q1,q2; void transferMessage() { strict_lock_ptr<std::queue<MessageType> > u1 = q1.synchronize(); strict_lock_ptr<std::queue<MessageType> > u2 = q2.synchronize(); if(!u1->empty()) { u2->push_back(u1->front()); u1->pop_front(); } } This works well in some scenarios, but not all - if the same two objects are updated together in different sections of code then you need to take care to ensure that the strict_lock_ptr objects are constructed in the same sequence in all cases, otherwise you have the potential for deadlock. This is just the same as when acquiring any two mutexes. In order to be able to use the dead-lock free lock algorithms we need to use instead unique_lock_ptr, which is Lockable. synchronized_value<std::queue<MessageType> > q1,q2; void transferMessage() { unique_lock_ptr<std::queue<MessageType> > u1 = q1.unique_synchronize(boost::defer_lock); unique_lock_ptr<std::queue<MessageType> > u2 = q2.unique_synchronize(boost::defer_lock); boost::lock(u1,u2); // dead-lock free algorithm if(!u1->empty()) { u2->push_back(u1->front()); u1->pop_front(); } } [endsect] [/Operations Across Multiple Objects]

6 19

[asio] Randomly having problems reading from the socket
by Torben Wiggerich 29 Jul '13

29 Jul '13

Hi all, I have some problems using the boost.asio.read for a TCP-socket. So far it works fine, but it randomly stops the transfer for at least 5 seconds. To resolve the error I used a simple synchronous server and client from the boost examples and modified it too send a larger amount of data. (307400 Bytes; this size comes from the program I'm trying to get run). On the client side I also changed the reading from the socket to read the complete data with boost.asio.read and transfer_all as argument. Both, server and client, measure the time for sending and reading to the socket and will give an error if it needs more than 1 second. Here is the sourcecode for the server: #include <iostream> #include <string> #include <boost/asio.hpp> #include <boost/date_time/posix_time/posix_time.hpp> using boost::asio::ip::tcp; using namespace boost::posix_time; int main() { try { boost::asio::io_service io_service; tcp::acceptor acceptor(io_service, tcp::endpoint(tcp::v4(), 8002)); tcp::socket socket(io_service); acceptor.accept(socket); unsigned char * array = new unsigned char[307400]; for (;;) { boost::system::error_code ignored_error; ptime startTime = microsec_clock::universal_time(); boost::asio::write(socket, boost::asio::buffer( array, 307400 ), boost::asio::transfer_all(), ignored_error); time_duration neededTime = microsec_clock::universal_time() - startTime; if ( neededTime.total_milliseconds() > 1000 ) { std::cout << "ERROR needed too much time: " << neededTime.total_milliseconds() << "ms" << std::endl; } } } catch (std::exception& e) { std::cerr << e.what() << std::endl; } return 0; } My client sourcecode: #include <iostream> #include <boost/array.hpp> #include <boost/asio.hpp> #include <boost/date_time/posix_time/posix_time.hpp> using boost::asio::ip::tcp; using namespace boost::posix_time; int main(int argc, char* argv[]) { try { if (argc != 2) { std::cerr << "Usage: client <host>" << std::endl; return 1; } boost::asio::io_service io_service; boost::asio::ip::tcp::endpoint endpoint( boost::asio::ip::address::from_string( argv[1] ), 8002 ); tcp::socket socket(io_service); boost::system::error_code error = boost::asio::error::host_not_found; socket.connect( endpoint, error ); if (error) throw boost::system::system_error(error); int counter = 0; unsigned char* array = new unsigned char[307400]; for (;;) { boost::system::error_code error; ptime startTime = microsec_clock::universal_time(); size_t len = boost::asio::read( socket, boost::asio::buffer( array, 307400 ), boost::asio::transfer_all(), error ); time_duration neededTime = microsec_clock::universal_time() - startTime; if ( error ) { printf( "body read error %s\n", error.message().c_str() ); } if ( counter % 5000 == 0 ) { std::cout << "passed: " << counter << "\r"; } ++counter; if ( neededTime.total_milliseconds() > 1000 ) { std::cout << "ERROR needed too much time: " << neededTime.total_milliseconds() << "ms" << std::endl; } } } catch (std::exception& e) { std::cerr << e.what() << std::endl; } return 0; } To reproduce the error just let it run for a while. It can take up to 30 minutes or even more... After a while it will produce the line: "ERROR needed too much time: 5007ms". Maybe with slightly different times, but all around 5 seconds. I tested it on different machines with Windows Vista and Seven. So am I'm doing sth. wrong? Is the reading from the socket correct? I'm using boost version 1.44. Kind regards Torben Wiggerich

6 12

safe bool not safe enough ?
by John Maddock 28 Jul '13

28 Jul '13

Just discovered (oops!) that the so called safe bool ideom is not as safe as it appears, for example: class Testable { bool ok_; typedef void (Testable::*bool_type)() const; void this_type_does_not_support_comparisons() const {} public: explicit Testable(bool b=true):ok_(b) {} operator bool_type() const { return ok_==true ? &Testable::this_type_does_not_support_comparisons : 0; } }; Testable t(true); bool b = t; // Compiles OK - Ooops! Which is causing multiprecision to misbehave when used in conjunction with uBlas: https://svn.boost.org/trac/boost/ticket/8292#comment:2 I guess making the conversion explicit in C++11 mode would help (I still need to test that), but is there a C++03 solution? Thanks, John.

4 9

Status of various Boost initiatives?
by Robert Ramey 21 Jul '13

21 Jul '13

I'm trying to get a handle on the current state of the various boost migrations which have been underway. a) migration to GIT b) migration to CMake c) status of rypll when I try to track this down I find many dead links, repeated information. I also don't find some blogs I used to be able to find on these subjects. Anyone up to provide an current status snapshot? Robert Ramey

5 14

A more convenient Variant visitation syntax
by Kevin Wu Won 19 Jul '13

19 Jul '13

While Boost Variant is a wonderful library that fills a genuine hole in the C++ language, it is not as nice to use as it could be. The "correct" way to unwrap a variant is to apply a static visitor, but this method carries a high syntactic burden because it needs the user to define a class (probably somewhere far away) just so they can "switch" on the type of the object stored in the variant. I came up with a solution where the handler functions can be specified inline with C++11 lambdas. Here's an example: boost::variant< int, std::string > u("hello world"); int result = match(u, [](int i) -> int { return i; }, [](const std::string & str) -> int { return str.length(); }); The `match` function accepts the variant followed by the handler functions. The functions can be specified in any order. It will fail to compile if the functions do not match the types of the variant, if the return types are not all the same, or if a non-unary function is supplied. This is C++11 only because it's quite pointless without lambda functions. I've tested it with gcc 4.7. It doesn't work on gcc 4.6, which can't handle the variadic templates. Here's the code: https://github.com/exclipy/inline_variant_visitor What do you think? This started out for me as an exercise to learn template metaprogramming and C++11, but hopefully, it can actually evolve into something useful.

7 8

Git Modularization example Boost .gitattributes
by Niall Douglas 16 Jul '13

16 Jul '13

> > Shouldn't the repositories contain a .gitattributes file indicating the > > eol flavor to be used for text files where it has significance? > > Perhaps! I don't know anything about .gitattributes. Where can I find > out more? Dave, I can probably save you some work here with my "perfect" mirror of Boost's EOL and MIME type config into a .gitattributes with which I configured my subgit to mirror my git repo into Boost sandbox. Taken from https://github.com/ned14/TripleGit/blob/master/.gitattributes: * text=auto !eol svneol=native#text/plain *.gitattributes text svneol=native#text/plain # Scriptish formats *.bat text svneol=native#text/plain *.bsh text svneol=native#text/x-beanshell *.cgi text svneol=native#text/plain *.cmd text svneol=native#text/plain *.js text svneol=native#text/javascript *.php text svneol=native#text/x-php *.pl text svneol=native#text/x-perl *.pm text svneol=native#text/x-perl *.py text svneol=native#text/x-python *.sh eol=lf svneol=LF#text/x-sh configure eol=lf svneol=LF#text/x-sh # Image formats *.bmp binary svneol=unset#image/bmp *.gif binary svneol=unset#image/gif *.ico binary svneol=unset#image/ico *.jpeg binary svneol=unset#image/jpeg *.jpg binary svneol=unset#image/jpeg *.png binary svneol=unset#image/png *.tif binary svneol=unset#image/tiff *.tiff binary svneol=unset#image/tiff *.svg text svneol=native#image/svg%2Bxml # Data formats *.pdf binary svneol=unset#application/pdf *.avi binary svneol=unset#video/avi *.doc binary svneol=unset#application/msword *.dsp text svneol=crlf#text/plain *.dsw text svneol=crlf#text/plain *.eps binary svneol=unset#application/postscript *.gz binary svneol=unset#application/gzip *.mov binary svneol=unset#video/quicktime *.mp3 binary svneol=unset#audio/mpeg *.ppt binary svneol=unset#application/vnd.ms-powerpoint *.ps binary svneol=unset#application/postscript *.psd binary svneol=unset#application/photoshop *.rdf binary svneol=unset#text/rdf *.rss text svneol=unset#text/xml *.rtf binary svneol=unset#text/rtf *.sln text svneol=native#text/plain *.swf binary svneol=unset#application/x-shockwave-flash *.tgz binary svneol=unset#application/gzip *.vcproj text svneol=native#text/xml *.vcxproj text svneol=native#text/xml *.vsprops text svneol=native#text/xml *.wav binary svneol=unset#audio/wav *.xls binary svneol=unset#application/vnd.ms-excel *.zip binary svneol=unset#application/zip # Text formats .htaccess text svneol=native#text/plain *.bbk text svneol=native#text/xml *.cmake text svneol=native#text/plain *.css text svneol=native#text/css *.dtd text svneol=native#text/xml *.htm text svneol=native#text/html *.html text svneol=native#text/html *.ini text svneol=native#text/plain *.log text svneol=native#text/plain *.mak text svneol=native#text/plain *.qbk text svneol=native#text/plain *.rst text svneol=native#text/plain *.sql text svneol=native#text/x-sql *.txt text svneol=native#text/plain *.xhtml text svneol=native#text/xhtml%2Bxml *.xml text svneol=native#text/xml *.xsd text svneol=native#text/xml *.xsl text svneol=native#text/xml *.xslt text svneol=native#text/xml *.xul text svneol=native#text/xul *.yml text svneol=native#text/plain boost-no-inspect text svneol=native#text/plain CHANGES text svneol=native#text/plain COPYING text svneol=native#text/plain INSTALL text svneol=native#text/plain Jamfile text svneol=native#text/plain Jamroot text svneol=native#text/plain Jamfile.v2 text svneol=native#text/plain Jamrules text svneol=native#text/plain Makefile* text svneol=native#text/plain README text svneol=native#text/plain TODO text svneol=native#text/plain # Code formats *.c text svneol=native#text/plain *.cpp text svneol=native#text/plain *.h text svneol=native#text/plain *.hpp text svneol=native#text/plain *.ipp text svneol=native#text/plain *.tpp text svneol=native#text/plain *.jam text svneol=native#text/plain *.java text svneol=native#text/plain Hope that's useful. Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

2 4

Git Modularization hiccups
by Beman Dawes 15 Jul '13

15 Jul '13

* "git clone --recursive http://github.com/boostorg/boost modular-boost" is mostly working fine here (on Win7) but is producing one set of error messages: Cloning into 'libs/assign'... fatal: reference is not a tree: 57ec5d1534810090649b18c88e66a46f48cdcf1c ... Unable to checkout '57ec5d1534810090649b18c88e66a46f48cdcf1c' in submodule path 'libs/assign' The remaining hiccups are in the root directory, comparing trunk to master: * boost.css is missing content from revisions 36243 and 53553. * boost-build.jam has different comments and history. Something is totally whacky. * boostcpp.py contents are the same, but the trunk file has Unix line endings, the master file has Windows line endings. * Same problem with bootstrap.sh. IIRC, it is important that the .sh files have the Unix line endings. * c++boost.gif not present in trunk, present in master. * index.html missing in master. * Jamfile.v2 and Jamroot.jam not present in trunk, present in master. * INSTALL missing in master. * LICENSE_1_0.txt has Unix line endings in trunk, Windows line endings in master. * project-config.jam missing in master. * rst.cc missing in master. * README.txt not present in trunk, present in master. HTH, --Beman

9 17

[filesystem] Please take care of #8706
by Antony Polukhin 10 Jul '13

10 Jul '13

Hi, There is a ticket https://svn.boost.org/trac/boost/ticket/8706 and patch in it that fixes compilation of Boost.Filesystem under Android NDK. Tested patch under latest NDK and it works well. Fix is required to start regression tests for droid platform. -- Best regards, Antony Polukhin

4 8

Re: [boost] [utility][thread] result_of - erroneous result type from a C++11 lambda
by Klaim - Joël Lamotte 04 Jul '13

04 Jul '13

On Tue, Apr 2, 2013 at 7:16 PM, Vicente J. Botet Escriba < vicente.botet(a)wanadoo.fr> wrote: > I've started to use C++11 lambda functions with Boost.Thread. > > The following works with clang-3.2 > > boost::future<int> f1 = boost::async( []() -> int {return 123;} ); > > > But it fails with gcc-4.6.2, 4.7.2 and 4.8.0 > > ../example/lambda_future.cpp:**25:91: erreur: conversion from > ‘boost::future<void>’ to non-scalar type ‘boost::future<int>’ requested > boost::future<int> f1 = boost::async( []() -> int {return 123;} ); > > The current implementation of boost::async uses boost::result_of to get > the result type of the callable parameter. > > Is this a know bug on boost::result_of or gcc compiler? > I'm seeing exactly the same behaviour in *VS2012 Update 2*. I'm using Boost 1.54.0 beta *r84748* To be more precise: 1) I first was just using boost::future and tried to use the new .then(), here is a full repro: #include <boost/thread/future.hpp> auto ft = boost::async( []{ return 42; } ).then( []( boost::future<int> r ){ return 666; } ); This fails because boost::async() returned a future<void> instead of a future<int>. I suspect the then() call to have the same problem. I can provide the full error log but I think it's not that useful. 2) Just to be sure I tried this full test: #include <boost/thread/future.hpp> int main() { auto ft = boost::async( []{ return 42; } ); // SUCCEED: static_assert( std::is_same< decltype(ft), boost::future<void> >::value, "WTF???" ); // FAILS: static_assert( std::is_same< decltype(ft), boost::future<int> >::value, "Not the expected type!" ); } Both asserts confirm that I don't get what I want. 3) I remembered that there were some issues from usage of boost::result_of in Boost.Log, so to clarify the situation I setup the following full test: #include <boost/utility/result_of.hpp> #include <type_traits> int top() { return 42; } struct K { int operator()(){ return 42; } typedef int value_type; }; auto F = []{ return 42; }; int main() { // A: ALL SUCCEED static_assert( std::is_same< decltype(K()()), int >::value, "Not the expected type!" ); static_assert( std::is_same< decltype(top()), int >::value, "Not the expected type!" ); static_assert( std::is_same< decltype(F()), int >::value, "Not the expected type!" ); // B: ALL SUCCEED static_assert( std::is_same< std::result_of<K()>::type, int >::value, "Not the expected type!" ); static_assert( std::is_same< std::result_of<decltype(top)>::type, int >::value, "Not the expected type!" ); static_assert( std::is_same< std::result_of<decltype(F)()>::type, int >::value, "Not the expected type!" ); // C: ALL SUCCEED std::result_of<K()>::type a = K()(); std::result_of<decltype(top)>::type b = top(); std::result_of<decltype(F)()>::type c = F(); // D: ALL FAILS static_assert( std::is_same< boost::result_of<K()>::type, int >::value, "Not the expected type!" ); static_assert( std::is_same< boost::result_of<decltype(top)>::type, int >::value, "Not the expected type!" ); static_assert( std::is_same< boost::result_of<decltype(F)()>::type, int >::value, "Not the expected type!" ); // E: ALL FAILS boost::result_of<K()>::type d = K()(); // error C2182: 'd' : illegal use of type 'void' boost::result_of<decltype(top)>::type e = top(); // error C2182: 'e' : illegal use of type 'void' boost::result_of<decltype(F)()>::type f = F(); // error C2182: 'f' : illegal use of type 'void' } This shows clearly that: 1. boost::result_of don't behave like std::result_of on this platform (and from previous discussions, on other platforms too). 2. both std::result_of and decltype() provide the result I expect from reading documentations about these. So far I'm assuming that the problem really is from boost::result_of, but I might be wrong because the differences with std::result_of are not clear to me. ---- Unfortunately this makes future.then() unusable if we expect return types. I don't know if it impacts other libraries (I suspect Boost.Log). Should I report a bug or is it known, already fixed or a misuse? Joel Lamotte

5 12

[result_of] Documentation update for ticket 7753
by Nathan Crookston 03 Jul '13

03 Jul '13

Hi Daniel & all, I'm updating the patch for ticket 7753 ( https://svn.boost.org/trac/boost/ticket/7753) I've made the requested changes to the patch, but I had a question on how to best explain which macro to define if, for example, you want result_of to work with C++11 lambdas. In the past, users with a pre-N3276 decltype have been advised to just #define BOOST_RESULT_OF_USE_DECLTYPE, with the explanation that "it's probably just going to work." While that advice is true, there are cases where this doesn't work; hence the addition of BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK. To explain why you'd define the FALLBACK macro over the USE_DECLTYPE macro, I'm thinking of including a paragraph like the following. "The question naturally arises on why have both BOOST_RESULT_OF_USE_DECLTYPE and BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK. In many situations, BOOST_RESULT_OF_USE_DECLTYPE will work well, even with pre-N3276 decltype. However, there are cases where a post-N3276 decltype is required to correctly deduce the return type of a functor. If a translation unit includes a functor whose return type is only deducible with TR1 or a post-N3276 decltype, using result_of with, e.g. a C++11 lambda function, will fail without BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK. If the macro BOOST_NO_CXX11_DECLTYPE_N3276 is defined and BOOST_NO_CXX11_DECLTYPE is not defined when including result_of.hpp, defining BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK is the safest option that will allow you to deduce C++11 lambda return types." My question is, am I over explaining it? Of course, I'd rather have BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK defined automatically for compilers like VC10, g++4.5, etc., and include text like the following: "If you rely on the result of calling a nullary functor to be void, regardless of the actual return type, or if your code is not written to handle cases other than BOOST_RESULT_OF_USE_TR1 and BOOST_RESULT_OF_USE_DECLTYPE, you may wish to explicitly define one of those symbols prior to including result_of." Either way, comments welcome. Thanks, Nate

3 4

[Serialization] Constructor for polymorphic archives
by Bjorn Reese 03 Jul '13

03 Jul '13

I have a set of my own Boost.Serialization archives (e.g. [1]) that I wish to write polymorphic variants of. I have tried to follow the blueprint from polymorphic_text_iarchive, which inherits from polymorphic_iarchive_route. The problem is that the constructor of my archives takes iterators (begin and end) as arguments, but the polymorphic_iarchive_route constructor expects a std::stream argument. Is there any workaround for this? [1] http://sourceforge.net/p/protoc/code/ci/master/tree/include/protoc/transenc…

3 4

Any interest in bitstream class?
by Paul Long 02 Jul '13

02 Jul '13

Same semantics as, e.g., stringstream, but it operates on binary data. I already have the analogues to istringstream/stringbuf (you can take a look at ibitstream/bitbuf at https://github.com/dplong/bstream) There are some interesting features, but I won't go into them here. If there is interest, I would implement obitstream and bitstream and possibly support Boost::dynamic_bitset. The rationale is _succinct_ expression of predictive parsing of binary data. I've used ibitstream in production code for decoding RTP headers and frames of various video encodings. Below is a simple function that decodes an RTP header using ibitstream; I also have a GitHub repo that contains more complex code for high-level parsing of H.264 frames at https://github.com/dplong/rtspudph264 struct RtpHeader { bool padding, marker; bitset<7> payloadType; WORD sequenceNumber; DWORD timestamp, ssrcIdentifier; vector<DWORD> csrcIdentifier; struct { bool present; WORD identifier; vector<BYTE> contents; } extension; }; bool ParseRtpHeader(const BYTE *buffer, RtpHeader &rtp) { ibitstream bin(buffer); static const bitset<2> version(0x2); bitset<4> csrcCount; WORD extensionLength; bin >> version >> rtp.padding >> rtp.extension.present >> csrcCount >> rtp.marker >> rtp.payloadType >> rtp.sequenceNumber >> rtp.timestamp >> rtp.ssrcIdentifier >> setrepeat(csrcCount.to_ulong()) >> rtp.csrcIdentifier; if (rtp.extension.present) { bin >> rtp.extension.identifier >> extensionLength >> setrepeat(extensionLength * sizeof(DWORD)) >> rtp.extension.contents; } return bin.good(); }

10 47

Static initialization of boost shared objects question
by Juan Carlos Franzoy 02 Jul '13

02 Jul '13

Hello. Thanks for reading my question. I fell into a deadlock in static initialization of boost shared objects. The deadlock occurs in a reentrant call to a function which contains a definition of a static variable. Apparenlty gcc protects the initialization of such variables with a condition variable. Looking at the c++ code nothing at all make anybody suspect about reentrancy. My "interpretation of the fact" may be titled 'something in gcc, ld, ld.so, c++language made the call to be reentrant' - There is a function boost::system::generic_category() that has a static variable V - V type is boost::system::annonymous-namespace::generic_error_category - boost::system::annonymous-namespace::generic_error_category is subclass of boost::system::error_category. - boost::system::annonymous-namespace::generic_error_category has no declared/defined constructor as well as all its superclasses - The compilation process generate the constructor boost::system::error_category::error_category() as a weak symbol inside every shared object that uses it. - There is a static variable boost::system::posix_category in one of the shared objects that is initialized calling boost::system::generic_category(). - when the static initialization of a shared object boost::system::posix_category get initialized - which calls boost::system::generic_category() - Inside boost::system::generic_category() starts the initialization of V which calls boost::system::error_category::error_category() - It may happend that the runtime calls an instance of boost::system::error_category::error_category() that resides in a shared object that is still not loaded - So that .so get loaded and it is called its own static initialization - which can call boost::system::generic_category() - BOOM I would love if you can confirm of refute my humble "interpretation". Details follows ------------------- boost version: 1-52-0 Operating system: uname -a SunOS bcpp-solaris10 5.10 Generic_147441-25 i86pc i386 i86pc $ gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/export/home/local/gcc-4.6.2/libexec/gcc/i386-pc-solaris2.10/4.6.2/lto-wrapper Target: i386-pc-solaris2.10 Configured with: ../src/gcc-4.6.2/configure --prefix=/export/home/local/gcc-4.6.2 --with-gmp=/export/home/local/gcc-4.6.2/gmp-4.3.2 --with-mpfr=/export/home/local/gcc-4.6.2/mpfr-3.0.0 --with-mpc=/export/home/local/gcc-4.6.2/mpc-0.8.2 --with-libelf=/export/home/local/gcc-4.6.2/libelf-0.8.12 --enable-shared --enable-threads=posix --enable-checking=release --with-system-zlib --enable-__cxa_atexit --enable-languages=c,c++ --with-as=/usr/local/bin/as --with-gnu-as --with-ld=/usr/ccs/bin/ld --without-gnu-ld --enable-plugin --enable-multilib --enable-version-specific-runtime-libs --enable-bootstrap --enable-ssp --enable-libssp --with-included-gettext --enable-lto --host=i386-pc-solaris2.10 --build=i386-pc-solaris2.10 Thread model: posix gcc version 4.6.2 (GCC) Callstack backtrace (lines begining with = are my comments): = = deadlock here: the threads is waiting itself = #0 0xfd459019 in __lwp_park () from /lib/libc.so.1 #1 0xfd45365e in cond_sleep_queue () from /lib/libc.so.1 #2 0xfd453817 in cond_wait_queue () from /lib/libc.so.1 #3 0xfd453b94 in cond_wait_common () from /lib/libc.so.1 #4 0xfd453d02 in _cond_wait () from /lib/libc.so.1 #5 0xfd453d2d in cond_wait () from /lib/libc.so.1 #6 0xfd453d66 in pthread_cond_wait () from /lib/libc.so.1 #7 0xfd632898 in __gthread_cond_wait (g=0xfd822ea8) at ...build-gcc/out/i386-pc-solaris2.10/libstdc++-v3/include/i386-pc-solaris2.10/bits/gthr-default.h:846 #8 __gthread_cond_wait_recursive (g=0xfd822ea8) at ...work/build-gcc/out/i386-pc-solaris2.10/libstdc++-v3/include/i386-pc-solaris2.10/bits/gthr-default.h:860 #9 __gnu_cxx::__cond::wait_recursive (g=0xfd822ea8) at ...build-gcc/out/i386-pc-solaris2.10/libstdc++-v3/include/ext/concurrence.h:377 #10 __cxa_guard_acquire (g=0xfd822ea8) at .../src/gcc-4.6.2/libstdc++-v3/libsupc++/guard.cc:289 = = Reentrant call to boost::system::generic_category() = #11 0xfd812313 in boost::system::generic_category () at libs/system/src/error_code.cpp:425 #12 0xfe85cd38 in __static_initialization_and_destruction_0(__initialize_p=1, __priority=65535) at ./boost/system/error_code.hpp:214 #13 0xfe85d05f in _GLOBAL__sub_I_instantiate_re2c_lexer_str.cpp () at libs/wave/src/instantiate_re2c_lexer_str.cpp:56 = = static initization of boost.wave library = #14 0xfe8868fd in __do_global_ctors_aux () from ...boost/lib/libboost_wave-gcc46-mt-d-32-SOLARIS-X86-1_52.so.1.52.0 #15 0xfe88692a in _init () from ...boost/lib/libboost_wave-gcc46-mt-d-32-SOLARIS-X86-1_52.so.1.52.0 #16 0xfefce37e in call_init () from /usr/lib/ld.so.1 #17 0xfefce1cf in is_dep_init () from /usr/lib/ld.so.1 #18 0xfefdaa4b in elf_bndr () from /usr/lib/ld.so.1 #19 0xfefc2ab4 in elf_rtbndr () from /usr/lib/ld.so.1 #20 0xfee60688 in ?? () #21 0xfee0c8f6 in boost::exception_detail::get_static_exception_object<boost::exception_detail::bad_alloc_>() at ./boost/exception/detail/exception_ptr.hpp:119 #22 0xfee0c0d2 in __static_initialization_and_destruction_0(__initialize_p=1, __priority=65535) at ./boost/exception/detail/exception_ptr.hpp:138 #23 0xfee0c271 in _GLOBAL__sub_I_future.cpp () at libs/thread/src/future.cpp:60 = = static initization of boost.thread library = #24 0xfee0d98d in __do_global_ctors_aux () from ...boost/lib/libboost_thread-gcc46-mt-d-32-SOLARIS-X86-1_52.so.1.52.0 #25 0xfee0d9ba in _init () from ...boost/lib/libboost_thread-gcc46-mt-d-32-SOLARIS-X86-1_52.so.1.52.0 #26 0xfefce37e in call_init () from /usr/lib/ld.so.1 #27 0xfefce1cf in is_dep_init () from /usr/lib/ld.so.1 #28 0xfefdaa4b in elf_bndr () from /usr/lib/ld.so.1 #29 0xfefc2ab4 in elf_rtbndr () from /usr/lib/ld.so.1 #30 0xfdce0688 in ?? () = = First calll to boost::system::generic_category() = #31 0xfd81232a in boost::system::generic_category () at libs/system/src/error_code.cpp:425 #32 0xfd812386 in __static_initialization_and_destruction_0(__initialize_p=1, __priority=65535) at ./boost/system/error_code.hpp:214 #33 0xfd8123ed in _GLOBAL__sub_I_error_code.cpp () at libs/system/src/error_code.cpp:430 = = static initialization of boost.system = #34 0xfd8126ed in __do_global_ctors_aux () from ...boost/lib/libboost_system-gcc46-mt-d-32-SOLARIS-X86-1_52.so.1.52.0 #35 0xfd81271a in _init () from ...boost/lib/libboost_system-gcc46-mt-d-32-SOLARIS-X86-1_52.so.1.52.0 #36 0xfefce37e in call_init () from /usr/lib/ld.so.1 #37 0xfefcd7d5 in setup () from /usr/lib/ld.so.1 #38 0xfefdba3e in _setup () from /usr/lib/ld.so.1 #39 0xfefc299c in _rt_boot () from /usr/lib/ld.so.1 #40 0x08047540 in ?? () #41 0x08047670 in ?? () More thanks for reading all.

3 4

[range] Time to merge Oven-to-Boost Extensions?
by Michel Morin 30 Jun '13

30 Jun '13

Hi, IIRC, the formal review is not necessary for the merge of Akira's Oven-to-Boost Extensions; only the range authors' review/permission are necessary. Neil, Nate, could we merge the extensions in the near future? I think everyone wants * `dropped` adaptor * `elements` adaptor * `taken` adaptor * `regular` utility so merging these first (and eventually merging the rest) would make the users happy. Regards, Michel

4 4

Re: [boost] Any interest in bitstream class?
by Brian Wood 30 Jun '13

30 Jun '13

From: Rob Stewart > On Jun 28, 2013, at 6:50 PM, Paul Long <plong(a)packetizer.com> wrote: > >> Correct, but it is important to note that integrals are always encoded big endian in the bitstream. I >>suppose it's possible that someone would want some other endian, but that's got to be an obscure use >>case. > > There are plenty of little endian only contexts that would want to avoid the host->network->host > conversions for all transfers. The C++ Middleware Writer uses a "receiver makes right" approach to support that. There's a SameFormat class here: http://webEbenezer.net/misc/Formatting.hh that's used when both sides have the same endian-ness. -- Brian Ebenezer Enterprises - Was Eisenhower the last decent US President? http://webEbenezer.net

2 1

Re: [boost] [Boost-users] Herb Sutter on C++ Standardization and Visual Studio
by Nathan Ridge 30 Jun '13

30 Jun '13

> Herb Sutter on C++ Standardization at Microsoft. > > http://channel9.msdn.com/Events/Build/2013/2-306 > > SGL Pretty good news, IMO. In addition to the C++11 and C++14 plans, Herb announced that Microsoft would complete the holes in their C++98 standard support by finally fixing their preprocessor and implementing correct two-phase name lookup (39:18 in the video). Perhaps the last discussion about these things [1] helped to tip the scale. In any case, I'm glad to hear it. Regards, Nate [1] http://boost.2283326.n4.nabble.com/C-announcements-coming-tomorrow-td463790…

1 0

boost::thread dependency on boost::chrono (windows implementation)
by Christian Hägele 28 Jun '13

28 Jun '13

Hello, as boost::thread now depends on boost::chrono I have the following questions: In boost::chrono on windows the the steady_clock is implemented via QueryPerformanceCounter. This may lead to wrong results because on some systems QueryPerformanceCounter gives different results on different processors. In our software we encountered theses problems regularly on some customers machines and thus stopped using QueryPerformanceCounter without additional checking. The problem I'm talking about is described as a TODO in boost/chrono/system_clocks.hpp My questions is if functions like boost::thread::timed_join or boost::mutex::timed_wait may have similar problems on hardware where QueryPerformanceCounter gives wrong result. Is there a way (like a preprocessor macro) to have boost::thread use the old implementation independent from boost::chrono? Regards, Christian

8 10

[1.54.0] Release candidates available
by Marshall Clow 28 Jun '13

28 Jun '13

Release candidate files for 1.54.0 are available at http://boost.cowic.de/rc/ 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. This helps ensure the candidates build OK before we push them out to SourceForge. The files (and associated md5s) are: efbfbff5a85a9330951f243d0a46e4b9 *boost_1_54_0_rc1.tar.gz 15cb8c0803064faef0c4ddf5bc5ca279 *boost_1_54_0_rc1.tar.bz2 78a35834c45220a6164310e280abe675 *boost_1_54_0_rc1.zip 89e734ffd2afe0982b2d9fc21d033dba *boost_1_54_0_rc1.7z Thanks! -- The release managers

6 9

Re: [boost] Could the custom allocator for flyweight hashed_factory be the boost::interprocess::allocator?
by JOAQUIN M. LOPEZ MUÑOZ 28 Jun '13

28 Jun '13

H Jin, ________________________________________ De: Boost [boost-bounces(a)lists.boost.org] en nombre de Jin Chen [chenjin92(a)gmail.com] Enviado el: lunes, 24 de junio de 2013 19:56 Para: Boost(a)lists.boost.org Asunto: [boost] Could the custom allocator for flyweight hashed_factory be the boost::interprocess::allocator? > I want to use boost::flyweight to do the dedupilcation of > boost::interprocess::basic_string object. I wrote a small test program for > that. In my program: > The flyweight works fine with the interprocess::basic_string which uses the > interprocess::allocator only with the default hashed_factory. The default > hashed_factory is ideal except that it uses std::allocator instead of > interprocess::allocator. I followed the > http://www.boost.org/doc/libs/1_53_0/libs/flyweight/doc/tutorial/configurat… > specifier > of a custom hash_factory which can change its allocator to the interprocess > one, but then got insanely long compiler error that is super hard to > decode... This is a very interesting exercise! There are several problems with your solution: * First of all, hashed_factory, as Jonathan points out, assumes the allocator is default constructible. As boost::interprocess::allocator needs a segment manager at construction time, you can overcome this by writing a custom interprocess allocator that takes that info statically, i.e., from a type that returns the segment manager: struct memory_dat_segment_manager { typedef ipc::managed_mapped_file::segment_manager type; static type* get() { static ipc::managed_mapped_file* segment= new ipc::managed_mapped_file(ipc::open_or_create,"memory.dat",409600); return segment->get_segment_manager(); } }; template<typename T,typename SegmentManager> struct segment_allocator: boost::interprocess::allocator<T,typename SegmentManager::type> { typedef boost::interprocess::allocator<T,typename SegmentManager::type> super; segment_allocator():super(SegmentManager::get()){} template<typename T2> segment_allocator(const segment_allocator<T2,SegmentManager>& x):super(x){} super& base(){return *this;} template<typename T2> struct rebind{ typedef segment_allocator<T2,SegmentManager> other; }; friend void swap(segment_allocator& x,segment_allocator& y) { swap(x.base(),y.base()); } }; Note that segment_allocator is default constructible: the segment is created on the first call to memory_dat_segment_manager. * Now, the holder class (www.boost.org/libs/flyweight/doc/tutorial/configuration.html#holders ) needs also to place its content in shared memory. As none of the holders provided by Boost.Flyweight does this, we must define our own: template<typename SegmentManager,typename C> struct segment_holder_class:boost::flyweights::holder_marker { static C& get() { static C* pc=SegmentManager::get()-> find_or_construct<C>(typeid(segment_holder_class).name())(); return *pc; } }; template<typename SegmentManager> struct segment_holder:boost::flyweights::holder_marker { template<typename C> struct apply { typedef segment_holder_class<SegmentManager,C> type; }; }; Again, the holder uses a SegmentManager class to get access to the segment manager * Finally, you need an interprocess locking policy (www.boost.org/libs/flyweight/doc/tutorial/configuration.html#locking ), and again this needs to be custom-defined (note that, in order for labeled_recursive_mutex to be default constructible, we get the info needed at construction time (the name of the mutex) from a Name class much in the same way we did with SegmentManager before for the allocator and holder): template<typename Name> struct labeled_recursive_mutex { typedef boost::interprocess::named_recursive_mutex mutex_type; operator mutex_type&() { static mutex_type mutex( boost::interprocess::open_or_create,Name::get()); return mutex; } }; template<typename Name> struct labeled_locking:boost::flyweights::locking_marker { typedef labeled_recursive_mutex<Name> mutex_type; typedef boost::interprocess::scoped_lock< typename labeled_recursive_mutex<Name>::mutex_type> lock_type; }; There's a technical issue here (if you don't get the following explanation you might as well skip it): As the mutex used by Boost.Flyweight is created by the holder class and we are using a shared-memory custom holder, it turns out labeled_recursive_mutex is thus created in shared memory. But boost::interprocess::named_recursive_mutex cannot be created in shared memory: we solve the problem with operator mutex_type&(), which actually creates the real mutex as a static variable in regular memory. And we're done. Find attached a small complete program showing how to put all the pieces together. Best, Joaquín M López Muñoz Telefónica Digital ________________________________ Este mensaje se dirige exclusivamente a su destinatario. Puede consultar nuestra política de envío y recepción de correo electrónico en el enlace situado más abajo. This message is intended exclusively for its addressee. We only send and receive email on the basis of the terms set out at: http://www.tid.es/ES/PAGINAS/disclaimer.aspx

2 1

[Spirit] Retrieve informations out of tokens
by ... ... 27 Jun '13

27 Jun '13

Hi, I want to create a c++ syntax analysor (for creating auto-completion tools), and to help me, I want to use the boost.spirit library. In order to learn the basics of spirit, I executed this exercise. It is now working but I want to display the tokens' characters instead of counting tokens. The problem is I don't know the properties of the argument passed to my functor (the variable "t" in the code below). What is the type of this variable and what are the public method/attributes we can use on ? This is the code of my functor : struct counter{ counter() : j(0) {j = new int();} counter(const counter &model) : j(model.j) {} ~counter() {delete int;} template <typename Token> bool operator()(Token const& t){//I want to know the type of this variable t ++i; ++(*j); std::ostringstream oss; oss << "global : " << i << " membre : " << *j;//typeid(t).name(); printf("%s\n", oss.str().c_str()); return true; } int* j;}; The variable t will be relay to my functor by the following tokenize function : counter* foncteur = new counter();lex::tokenize(first, last, word_count_functor, *foncteur); I still have other questions : I read a consistent part of the documentation but I have not been able to define the type of regex used by boost.spirit. Which type is it ? What is the more appropriate function to use to analyse c++ synthax : tokenize or tokenize _and_parse ? You seems to describe tokenize_and_parse as a more powerful tool, but is it possible to define all the syntax of c++ using a parser ? Could I find an example of c++ syntax analysor using boost.spirit ? Any help would be appreciate,Cordialy,Guillaume Bersac237bis rue de Pessac33000 Bordeaux06.65.30.89.43

6 11

Interest in an 'either' library?
by David Sankel 26 Jun '13

26 Jun '13

**semantics**: template< typename left_type, typename right_type> struct either { // postcondition, is_left() either( left_type ); // postcondition, is_right() either( right_type ); bool is_left() const; bool is_right() const; // postcondition, is_left() either & operator=( left_type ); // postcondition, is_right() either & operator=( right_type ); // precondition, is_left() left_type left(); // precondition, is_right() right_type right(); private: }; **uses**: **Use 1**: Can be used as an alternative to exceptions or the (error codes+set reference idiom): either<error_code, file_id> load_file(...); vs. error_code load_file( file_id &, ... ); or // throws std::exception file_id load_file(...); **Use 2**: A lightweight alternative to boost::variant when only 2 components are required (either relates to variant in a similar way that pair relates to tuple ). variant<A,B> eitherAOrB; if( A * aPtr = boost::get<A>( &eitherAOrB ) ) std::cout << "A: " << *aPtr; else std::cout << "B: " << boost::get<B>( eitherAOrB ); vs. either<A,B> eitherAOrB; if( eitherAOrB.is_left() ) std::cout << "A: " << eitherAOrB.left(); else std::cout << "B: " << eitherAOrB.right(); --David Sankel

12 41

[1.54.0] Release notes
by Daniel James 26 Jun '13

26 Jun '13

Hello everyone, It's time to send me your release notes, or if you're feeling enthusiastic, you can add them yourself at: http://svn.boost.org/svn/boost/website/public_html/live/feed/history/ You see the notes so far at: http://www.boost.org/users/history/version_1_54_0.html And while I'm at it, I've also added the new libraries to: http://www.boost.org/doc/libs/1_54_0/ thank you, Daniel

11 16

[1.54.0][range] add release note
by Akira Takahashi 26 Jun '13

26 Jun '13

Hi, I think missing Boost.Range release note for 1.54.0. https://svn.boost.org/svn/boost/website/public_html/live/feed/history/boost… Please see changeset: https://svn.boost.org/trac/boost/changeset/84823 Changeset 84823 Timestamp:06/17/13 22:22:07 Author:nathanridge Message:[range] Merge Boost.Range bug fixes to release branch (fixes #6944; fixes #7407; fixes #7408; fixes #7731; fixes #7827; fixes #8338; fixes #8453). Thanks, Akira

2 1

[Boost][asio]How add a timeout to asio connection?
by Renato Forti 25 Jun '13

25 Jun '13

Hi All, I have one problem, I have this class to connect to my server app: class session { public: static void init( const std::string& host, const std::string& port, hades::archive::archive& iarch, hades::archive::archive& oarch) { boost::asio::io_service io_service; client client(io_service, host, port, iarch, oarch); io_service.run(); } }; The problem is : if my server is down, my client (session) will block on io_service.run(); the client nerves end. Then I try to add a time out: class client { public: /// Constructor starts the asynchronous connect operation. client(boost::asio::io_service& io_service, const std::string& host, const std::string& port, // service hades::archive::archive& iarch, hades::archive::archive& oarch) : connection_(io_service) , deadline_(io_service) , iarch_(&iarch) , oarch_(&oarch) { deadline_.async_wait(boost::bind(&client::check_deadline, this)); deadline_.expires_from_now(boost::posix_time::seconds(30)); // Resolve the host name into an IP address. boost::asio::ip::tcp::resolver resolver(io_service); boost::asio::ip::tcp::resolver::query query(host, port); boost::asio::ip::tcp::resolver::iterator endpoint_iterator = resolver.resolve(query); // Start an asynchronous connect operation. boost::asio::async_connect(connection_.socket(), endpoint_iterator, boost::bind(&client::handle_connect, this, boost::asio::placeholders::error)); } /// Handle completion of a connect operation. void handle_connect(const boost::system::error_code& e) { if (!e) { // Successfully established connection. Start operation to read the list // of stocks. The connection::async_read() function will automatically // decode the data that is read from the underlying socket. connection_.async_read(*oarch_, boost::bind(&client::handle_read, this, boost::asio::placeholders::error)); connection_.async_write(*iarch_, boost::bind(&client::handle_write, this, boost::asio::placeholders::error)) ; } else { // An error occurred. throw sync_client_exception(e.message()); } } // Handle completion of a write operation. void handle_write(const boost::system::error_code& e) { } // Handle completion of a read operation. void handle_read(const boost::system::error_code& e) { } void check_deadline() { // Check whether the deadline has passed. We compare the deadline against // the current time since a new asynchronous operation may have moved the // deadline before this actor had a chance to run. if (deadline_.expires_at() <= deadline_timer::traits_type::now()) { // The deadline has passed. The socket is closed so that any outstanding // asynchronous operations are cancelled. connection_.socket().close(); // There is no longer an active deadline. The expiry is set to positive // infinity so that the actor takes no action until a new deadline is set. deadline_.expires_at(boost::posix_time::pos_infin); throw sync_client_exception("Time out : deadline on client!"); } // Put the actor back to sleep. deadline_.async_wait(boost::bind(&client::check_deadline, this)); } private: // The connection to the server. dsafe::sync::connection connection_; // The data received from the server. hades::archive::archive *iarch_; hades::archive::archive *oarch_; deadline_timer deadline_; }; The problem is that now the timeout expires even if the connection to the server occurs. What is wrong? My timeout should be disabled when the connection is successful! How do I get it? Only when the connection fails it should be called! Thanks for clarification

3 2

Could the custom allocator for flyweight hashed_factory be the boost::interprocess::allocator?
by Jin Chen 25 Jun '13

25 Jun '13

I want to use boost::flyweight to do the dedupilcation of boost::interprocess::basic_string object. I wrote a small test program for that. In my program: The flyweight works fine with the interprocess::basic_string which uses the interprocess::allocator only with the default hashed_factory. The default hashed_factory is ideal except that it uses std::allocator instead of interprocess::allocator. I followed the http://www.boost.org/doc/libs/1_53_0/libs/flyweight/doc/tutorial/configurat… specifier of a custom hash_factory which can change its allocator to the interprocess one, but then got insanely long compiler error that is super hard to decode... Right now, I don't know if only use interprocess::allocator in interprocess::basic_string alone will make the flyweight object be shared by multiple process, guess probably not... Then wonder whether that I didn't use the right syntax for custom hashed_factory or flyweight is compatible with boost::interprocess at all... If it is compatible, what's the right syntax for that? How shall I change my code? Below is a test program attached. The code could compile now with flyweight's default hashed_factory. The goal is to make it compile with ShmStringHashedFactory which use the interprocess allocator.

2 1

Proposal for a thread "collision" detector
by Gaetano Mendola 24 Jun '13

24 Jun '13

I would like to know if Boost community could be interested in adopting a check mechanism that is able to detect if a not supposed thread safe class is used by multiple threads in unsafe way. This tecnique has saved us a lot of headache especially when code refactoring on old code is performed. Better to explain it, without enter in the detail of the implementation, with some examples: Example: Queue implementation non thread-safe but still usable if clients are synchronized somehow. class NonThreadSafeQueue { public: ... void push(int) { DFAKE_SCOPED_LOCK(push_pop_); ... } int pop() { DFAKE_SCOPED_LOCK(push_pop_); ... } ... private: DFAKE_MUTEX(push_pop_); }; Example: Queue implementation not usable even if clients are synchronized, so only one thread in the class life cycle can use the two members push/pop. In this case the macro DFAKE_SCOPED_LOCK_THREAD_LOCKED pins the specified critical section the first time a thread enters push or pop, from that time on only that thread is allowed to execute push or pop. class NonThreadSafeQueue { public: ... void push(int) { DFAKE_SCOPED_LOCK_THREAD_LOCKED(push_pop_); ... } int pop() { DFAKE_SCOPED_LOCK_THREAD_LOCKED(push_pop_); ... } ... private: DFAKE_MUTEX(push_pop_); }; Example: Class that has to be contructed/destroyed on same thread, it has a "shareable" method (with external syncronization) and a not shareable method (even with external synchronization). In this case 3 Critical sections have to be defined class ExoticClass { public: ExoticClass() { DFAKE_SCOPED_LOCK_THREAD_LOCKED(ctor_dtor_); ... } ~ExoticClass() { DFAKE_SCOPED_LOCK_THREAD_LOCKED(ctor_dtor_); ... } void Shareable() { DFAKE_SCOPED_LOCK(shareable_section_); ... } void NotShareable() { DFAKE_SCOPED_LOCK_THREAD_LOCKED(ctor_dtor_); ... } ... private: DFAKE_MUTEX(ctor_dtor_) DFAKE_MUTEX(shareable_section_) }; DFAKE_SCOPED_LOCK will "throw an exception" or will call an "abort" in case of check failed. This tecnique doesn't involve real lock/unlock but uses atomic operations, also the various macros DFAKE_XXXXXXXXX are defined void when NDEBUG is defined. Any comment is appreciated. Regards Gaetano Mendola

3 3

The release branch is CLOSED - except by specific permission
by Marshall Clow 24 Jun '13

24 Jun '13

We're counting down to release next Monday. -- Marshall Marshall Clow Idio Software <mailto:mclow.lists@gmail.com> A.D. 1517: Martin Luther nails his 95 Theses to the church door and is promptly moderated down to (-1, Flamebait). -- Yu Suzuki

1 0

Heads up - Release branch closed as of tomorrow
by Marshall Clow 24 Jun '13

24 Jun '13

Starting tomorrow (Monday, June 27), the release branch will be closed, except by permission from the release managers. -- Marshall Marshall Clow Idio Software <mailto:mclow.lists@gmail.com> A.D. 1517: Martin Luther nails his 95 Theses to the church door and is promptly moderated down to (-1, Flamebait). -- Yu Suzuki

3 5

[smart_ptr] enable_shared_from_this and shared_ptr to a base class
by Adam Romanek 24 Jun '13

24 Jun '13

Hi, I have a question related to using shared_from_this() and a shared_ptr to a base class. Here's a modified version of the enable_shared_from_this usage example from its documentation web page: #include <boost/enable_shared_from_this.hpp> #include <boost/shared_ptr.hpp> #include <cassert> class X { public: virtual void foo() = 0; }; class Y: public X, public boost::enable_shared_from_this<Y> { virtual void foo() { shared_from_this(); } }; int main() { X* x_ptr = new Y; boost::shared_ptr<X> sp(x_ptr); sp->foo(); } First, class Y is now derived from class X. Secondly, shared_ptr's template argument is now X and the parameter to the shared_ptr's constructor is now a pointer to X. Now, calling shared_from_this() in X and/or Y throws boost::bad_weak_ptr. Is this correct behavior? Is it documented somewhere? I know that the example is a bit unrealistic since most of the time shared_ptr is constructed directly from the pointer returned by 'new Y' or created by make_shared() but still, this is something that bothers me. WBR, Adam Romanek

3 9

Boost.Spirit how to use token in functor
by ... ... 24 Jun '13

24 Jun '13

Hi, I have a functor which is working, but its argument, which I don't know its type, I don't know what to do with it. I want to extract data out of it, I want to know is beginning and its end, I want to display the the content of the string character in my consol... but I can't retrieve this information. How could I archieve it ? What is the type of the argument relay to my function ? Is there a dOxygen like documentation (the one on the Boost site is great but a formal documentaton is also interesting). Where is the description and code source of this type ? Here is the code of my functor : struct counter{ counter() : j(0) {j = new int();} counter(const counter &model) : j(model.j) {} template <typename Token> bool operator()(Token const& t){// t is the argument I want to use ++i; ++(*j); std::ostringstream oss; oss << "global : " << i << " membre : " << *j;//typeid(t).name(); printf("%s\n", oss.str().c_str()); return true; } int* j;}; Thanks every one, cordialy,Guillaume Bersac237bis rue de Pessac33000 Bordeaux06.65.30.89.43

2 1

De Bruijn Bind (alternate bind syntax) Interest?
by David Sankel 24 Jun '13

24 Jun '13

Hello all, I've been working on an alternate bind syntax based on De Bruijn indices[1]. The syntax is very simple, yet the terms are very powerful. Here is an example of a function const that takes in an argument c and returns another function that, for all input, returns c: //λx.λy.x = λλ1 with De Bruijn indices. auto const_ = abs<1>( abs<1>( var<1,0>() ) ); More examples, further explanation, and an implementation are available here[2]. I'm thinking that this library could also be useful as a core for more syntax heavy bind variations. David [1] http://en.wikipedia.org/wiki/De_Bruijn_index [2] http://bitbucket.org/camior/de-bruijn-bind/ -- David Sankel Sankel Software www.sankelsoftware.com 585 617 4748 (Office)

11 73

Error while linking boost. spirit
by ... ... 23 Jun '13

23 Jun '13

Hi, I just downloaded, compiled and install boost.It seems like the installation process worked fine and I successfully compiled a program using boost (boost.log for instance). But when I try to compile an example writed by the developpers of boost.spirit, it fail ! It doesn't seem like it's an inclusion resolution problems, I don't know what to do. Please help me. Here is my code (I paste it from this page) : #include <stdio.h>#include <stdlib.h> #include <boost/spirit/include/lex_lexertl.hpp>#include <boost/spirit/include/phoenix_operator.hpp>#include <boost/spirit/include/phoenix_statement.hpp>#include <boost/spirit/include/phoenix_algorithm.hpp>#include <boost/spirit/include/phoenix_core.hpp>#define BOOST_ALL_DYN_LINK//without it boost.log glitch#include <boost/log/trivial.hpp> int main(){ BOOST_LOG_TRIVIAL(trace) << "boost.log is working !"; typedef lex::lexertl::token<char const*, lex::omit, boost::mpl::false_> token_type; typedef lex::lexertl::actor_lexer<token_type> lexer_type; word_count_tokens<lexer_type> word_count_lexer; std::string str (read_from_file("mainwindow.cpp.txt")); char const* first = str.c_str(); char const* last = &first[str.size()]; lexer_type::iterator_type iter = word_count_lexer.begin(first, last); lexer_type::iterator_type end = word_count_lexer.end(); while (iter != end && token_is_valid(*iter)) ++iter; if (iter == end) { std::cout << "lines: " << word_count_lexer.l << ", words: " << word_count_lexer.w << ", characters: " << word_count_lexer.c << "\n"; } else { std::string rest(first, last); std::cout << "Lexical analysis failed\n" << "stopped at: \"" << rest << "\"\n"; } return 0; }} And here is my error log : 11:32:39 **** Incremental Build of configuration Default for project synthax_analyser ****make all g++ -O2 -g -Wall -fmessage-length=0 -c -o synthax_analyser.o synthax_analyser.cppsynthax_analyser.cpp: In function ‘int main()’:synthax_analyser.cpp:24:4: error: ‘lex’ does not name a typesynthax_analyser.cpp:27:10: error: ‘lex’ does not name a typesynthax_analyser.cpp:29:2: error: ‘word_count_tokens’ was not declared in this scopesynthax_analyser.cpp:29:20: error: ‘lexer_type’ was not declared in this scopesynthax_analyser.cpp:29:20: note: suggested alternative:In file included from /usr/local/include/boost/spirit/home/lex/meta_compiler.hpp:16:0, from /usr/local/include/boost/spirit/home/lex/reference.hpp:14, from /usr/local/include/boost/spirit/home/lex/lexer/token_def.hpp:21, from /usr/local/include/boost/spirit/home/lex/lexer.hpp:14, from /usr/local/include/boost/spirit/home/lex.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:15, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/spirit/home/lex/lexer_type.hpp:20:12: note: ‘boost::spirit::lex::lexer_type’synthax_analyser.cpp:29:32: error: ‘word_count_lexer’ was not declared in this scopesynthax_analyser.cpp:31:54: error: ‘read_from_file’ was not declared in this scopesynthax_analyser.cpp:35:2: error: ‘lexer_type’ is not a class or namespacesynthax_analyser.cpp:35:28: error: expected ‘;’ before ‘iter’synthax_analyser.cpp:36:3: error: ‘lexer_type’ is not a class or namespacesynthax_analyser.cpp:36:29: error: expected ‘;’ before ‘end’synthax_analyser.cpp:38:9: error: ‘iter’ was not declared in this scopesynthax_analyser.cpp:38:17: error: ‘end’ was not declared in this scopesynthax_analyser.cpp:38:17: note: suggested alternatives:In file included from /usr/local/include/boost/range/empty.hpp:20:0, from /usr/local/include/boost/proto/functional/range/empty.hpp:12, from /usr/local/include/boost/proto/functional/range.hpp:13, from /usr/local/include/boost/proto/functional.hpp:14, from /usr/local/include/boost/proto/proto.hpp:16, from /usr/local/include/boost/spirit/home/support/terminal.hpp:18, from /usr/local/include/boost/spirit/home/support/common_terminals.hpp:15, from /usr/local/include/boost/spirit/home/lex/lexer/terminals.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer.hpp:13, from /usr/local/include/boost/spirit/home/lex.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:15, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/range/end.hpp:106:61: note: ‘boost::range_adl_barrier::end’In file included from /usr/local/include/boost/fusion/container/list/cons.hpp:14:0, from /usr/local/include/boost/fusion/iterator/segmented_iterator.hpp:13, from /usr/local/include/boost/fusion/sequence/intrinsic/detail/segmented_begin.hpp:11, from /usr/local/include/boost/fusion/sequence/intrinsic/begin.hpp:17, from /usr/local/include/boost/fusion/container/vector/vector10.hpp:15, from /usr/local/include/boost/fusion/container/vector.hpp:12, from /usr/local/include/boost/fusion/include/vector.hpp:10, from /usr/local/include/boost/spirit/home/phoenix/core/limits.hpp:73, from /usr/local/include/boost/spirit/home/phoenix/core.hpp:11, from /usr/local/include/boost/spirit/include/phoenix_core.hpp:14, from /usr/local/include/boost/spirit/home/support/terminal.hpp:16, from /usr/local/include/boost/spirit/home/support/common_terminals.hpp:15, from /usr/local/include/boost/spirit/home/lex/lexer/terminals.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer.hpp:13, from /usr/local/include/boost/spirit/home/lex.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:15, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/fusion/sequence/intrinsic/end.hpp:89:5: note: ‘boost::fusion::end’In file included from /usr/local/include/boost/fusion/sequence/intrinsic/begin.hpp:13:0, from /usr/local/include/boost/fusion/container/vector/vector10.hpp:15, from /usr/local/include/boost/fusion/container/vector.hpp:12, from /usr/local/include/boost/fusion/include/vector.hpp:10, from /usr/local/include/boost/spirit/home/phoenix/core/limits.hpp:73, from /usr/local/include/boost/spirit/home/phoenix/core.hpp:11, from /usr/local/include/boost/spirit/include/phoenix_core.hpp:14, from /usr/local/include/boost/spirit/home/support/terminal.hpp:16, from /usr/local/include/boost/spirit/home/support/common_terminals.hpp:15, from /usr/local/include/boost/spirit/home/lex/lexer/terminals.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer.hpp:13, from /usr/local/include/boost/spirit/home/lex.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:15, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/fusion/sequence/intrinsic_fwd.hpp:67:16: note: ‘boost::fusion::result_of::end’In file included from /usr/local/include/boost/fusion/support/sequence_base.hpp:11:0, from /usr/local/include/boost/fusion/container/vector/vector10.hpp:11, from /usr/local/include/boost/fusion/container/vector.hpp:12, from /usr/local/include/boost/fusion/include/vector.hpp:10, from /usr/local/include/boost/spirit/home/phoenix/core/limits.hpp:73, from /usr/local/include/boost/spirit/home/phoenix/core.hpp:11, from /usr/local/include/boost/spirit/include/phoenix_core.hpp:14, from /usr/local/include/boost/spirit/home/support/terminal.hpp:16, from /usr/local/include/boost/spirit/home/support/common_terminals.hpp:15, from /usr/local/include/boost/spirit/home/lex/lexer/terminals.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer.hpp:13, from /usr/local/include/boost/spirit/home/lex.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:15, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/mpl/begin_end_fwd.hpp:23:38: note: ‘boost::mpl::end’In file included from /usr/local/include/boost/proto/functional/range.hpp:14:0, from /usr/local/include/boost/proto/functional.hpp:14, from /usr/local/include/boost/proto/proto.hpp:16, from /usr/local/include/boost/spirit/home/support/terminal.hpp:18, from /usr/local/include/boost/spirit/home/support/common_terminals.hpp:15, from /usr/local/include/boost/spirit/home/lex/lexer/terminals.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer.hpp:13, from /usr/local/include/boost/spirit/home/lex.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:15, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/proto/functional/range/end.hpp:19:12: note: ‘boost::proto::functional::end’In file included from /usr/local/include/boost/range/empty.hpp:20:0, from /usr/local/include/boost/proto/functional/range/empty.hpp:12, from /usr/local/include/boost/proto/functional/range.hpp:13, from /usr/local/include/boost/proto/functional.hpp:14, from /usr/local/include/boost/proto/proto.hpp:16, from /usr/local/include/boost/spirit/home/support/terminal.hpp:18, from /usr/local/include/boost/spirit/home/support/common_terminals.hpp:15, from /usr/local/include/boost/spirit/home/lex/lexer/terminals.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer.hpp:13, from /usr/local/include/boost/spirit/home/lex.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:15, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/range/end.hpp:106:61: note: ‘boost::range_adl_barrier::end’In file included from /usr/local/include/boost/spirit/home/support/string_traits.hpp:16:0, from /usr/local/include/boost/spirit/home/support/nonterminal/expand_arg.hpp:20, from /usr/local/include/boost/spirit/home/support/context.hpp:18, from /usr/local/include/boost/spirit/home/qi/domain.hpp:18, from /usr/local/include/boost/spirit/home/qi/parser.hpp:15, from /usr/local/include/boost/spirit/home/lex/lexer/token_def.hpp:17, from /usr/local/include/boost/spirit/home/lex/lexer.hpp:14, from /usr/local/include/boost/spirit/home/lex.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:15, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/spirit/home/support/container.hpp:445:5: note: ‘boost::spirit::traits::end’In file included from /usr/local/include/boost/spirit/home/support/handles_container.hpp:14:0, from /usr/local/include/boost/spirit/home/lex/lexer/token_def.hpp:16, from /usr/local/include/boost/spirit/home/lex/lexer.hpp:14, from /usr/local/include/boost/spirit/home/lex.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:15, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/spirit/home/support/attributes_fwd.hpp:43:12: note: ‘boost::spirit::result_of::end’In file included from /usr/local/include/boost/spirit/home/support/info.hpp:17:0, from /usr/local/include/boost/spirit/home/lex/lexer/token_def.hpp:15, from /usr/local/include/boost/spirit/home/lex/lexer.hpp:14, from /usr/local/include/boost/spirit/home/lex.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:15, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/foreach.hpp:730:1: note: ‘boost::foreach_detail_::end’synthax_analyser.cpp:38:44: error: ‘token_is_valid’ was not declared in this scopesynthax_analyser.cpp:38:44: note: suggested alternatives:In file included from /usr/local/include/boost/spirit/home/lex/lexer/lexertl/lexer.hpp:20:0, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:16, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/spirit/home/lex/lexer/lexertl/token.hpp:415:5: note: ‘boost::spirit::lex::lexertl::token_is_valid’In file included from /usr/local/include/boost/spirit/home/lex/lexer/lexertl/iterator.hpp:18:0, from /usr/local/include/boost/spirit/home/lex/lexer/lexertl/lexer.hpp:23, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:16, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/spirit/home/support/iterators/detail/split_functor_input_policy.hpp:19:21: note: ‘boost::spirit::iterator_policies::split_functor_input_is_valid_test_::token_is_valid’synthax_analyser.cpp:41:7: error: ‘iter’ was not declared in this scopesynthax_analyser.cpp:41:15: error: ‘end’ was not declared in this scopesynthax_analyser.cpp:41:15: note: suggested alternatives:In file included from /usr/local/include/boost/range/empty.hpp:20:0, from /usr/local/include/boost/proto/functional/range/empty.hpp:12, from /usr/local/include/boost/proto/functional/range.hpp:13, from /usr/local/include/boost/proto/functional.hpp:14, from /usr/local/include/boost/proto/proto.hpp:16, from /usr/local/include/boost/spirit/home/support/terminal.hpp:18, from /usr/local/include/boost/spirit/home/support/common_terminals.hpp:15, from /usr/local/include/boost/spirit/home/lex/lexer/terminals.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer.hpp:13, from /usr/local/include/boost/spirit/home/lex.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:15, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/range/end.hpp:106:61: note: ‘boost::range_adl_barrier::end’In file included from /usr/local/include/boost/fusion/container/list/cons.hpp:14:0, from /usr/local/include/boost/fusion/iterator/segmented_iterator.hpp:13, from /usr/local/include/boost/fusion/sequence/intrinsic/detail/segmented_begin.hpp:11, from /usr/local/include/boost/fusion/sequence/intrinsic/begin.hpp:17, from /usr/local/include/boost/fusion/container/vector/vector10.hpp:15, from /usr/local/include/boost/fusion/container/vector.hpp:12, from /usr/local/include/boost/fusion/include/vector.hpp:10, from /usr/local/include/boost/spirit/home/phoenix/core/limits.hpp:73, from /usr/local/include/boost/spirit/home/phoenix/core.hpp:11, from /usr/local/include/boost/spirit/include/phoenix_core.hpp:14, from /usr/local/include/boost/spirit/home/support/terminal.hpp:16, from /usr/local/include/boost/spirit/home/support/common_terminals.hpp:15, from /usr/local/include/boost/spirit/home/lex/lexer/terminals.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer.hpp:13, from /usr/local/include/boost/spirit/home/lex.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:15, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/fusion/sequence/intrinsic/end.hpp:89:5: note: ‘boost::fusion::end’In file included from /usr/local/include/boost/fusion/sequence/intrinsic/begin.hpp:13:0, from /usr/local/include/boost/fusion/container/vector/vector10.hpp:15, from /usr/local/include/boost/fusion/container/vector.hpp:12, from /usr/local/include/boost/fusion/include/vector.hpp:10, from /usr/local/include/boost/spirit/home/phoenix/core/limits.hpp:73, from /usr/local/include/boost/spirit/home/phoenix/core.hpp:11, from /usr/local/include/boost/spirit/include/phoenix_core.hpp:14, from /usr/local/include/boost/spirit/home/support/terminal.hpp:16, from /usr/local/include/boost/spirit/home/support/common_terminals.hpp:15, from /usr/local/include/boost/spirit/home/lex/lexer/terminals.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer.hpp:13, from /usr/local/include/boost/spirit/home/lex.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:15, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/fusion/sequence/intrinsic_fwd.hpp:67:16: note: ‘boost::fusion::result_of::end’In file included from /usr/local/include/boost/fusion/support/sequence_base.hpp:11:0, from /usr/local/include/boost/fusion/container/vector/vector10.hpp:11, from /usr/local/include/boost/fusion/container/vector.hpp:12, from /usr/local/include/boost/fusion/include/vector.hpp:10, from /usr/local/include/boost/spirit/home/phoenix/core/limits.hpp:73, from /usr/local/include/boost/spirit/home/phoenix/core.hpp:11, from /usr/local/include/boost/spirit/include/phoenix_core.hpp:14, from /usr/local/include/boost/spirit/home/support/terminal.hpp:16, from /usr/local/include/boost/spirit/home/support/common_terminals.hpp:15, from /usr/local/include/boost/spirit/home/lex/lexer/terminals.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer.hpp:13, from /usr/local/include/boost/spirit/home/lex.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:15, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/mpl/begin_end_fwd.hpp:23:38: note: ‘boost::mpl::end’In file included from /usr/local/include/boost/proto/functional/range.hpp:14:0, from /usr/local/include/boost/proto/functional.hpp:14, from /usr/local/include/boost/proto/proto.hpp:16, from /usr/local/include/boost/spirit/home/support/terminal.hpp:18, from /usr/local/include/boost/spirit/home/support/common_terminals.hpp:15, from /usr/local/include/boost/spirit/home/lex/lexer/terminals.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer.hpp:13, from /usr/local/include/boost/spirit/home/lex.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:15, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/proto/functional/range/end.hpp:19:12: note: ‘boost::proto::functional::end’In file included from /usr/local/include/boost/range/empty.hpp:20:0, from /usr/local/include/boost/proto/functional/range/empty.hpp:12, from /usr/local/include/boost/proto/functional/range.hpp:13, from /usr/local/include/boost/proto/functional.hpp:14, from /usr/local/include/boost/proto/proto.hpp:16, from /usr/local/include/boost/spirit/home/support/terminal.hpp:18, from /usr/local/include/boost/spirit/home/support/common_terminals.hpp:15, from /usr/local/include/boost/spirit/home/lex/lexer/terminals.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer.hpp:13, from /usr/local/include/boost/spirit/home/lex.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:15, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/range/end.hpp:106:61: note: ‘boost::range_adl_barrier::end’In file included from /usr/local/include/boost/spirit/home/support/string_traits.hpp:16:0, from /usr/local/include/boost/spirit/home/support/nonterminal/expand_arg.hpp:20, from /usr/local/include/boost/spirit/home/support/context.hpp:18, from /usr/local/include/boost/spirit/home/qi/domain.hpp:18, from /usr/local/include/boost/spirit/home/qi/parser.hpp:15, from /usr/local/include/boost/spirit/home/lex/lexer/token_def.hpp:17, from /usr/local/include/boost/spirit/home/lex/lexer.hpp:14, from /usr/local/include/boost/spirit/home/lex.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:15, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/spirit/home/support/container.hpp:445:5: note: ‘boost::spirit::traits::end’In file included from /usr/local/include/boost/spirit/home/support/handles_container.hpp:14:0, from /usr/local/include/boost/spirit/home/lex/lexer/token_def.hpp:16, from /usr/local/include/boost/spirit/home/lex/lexer.hpp:14, from /usr/local/include/boost/spirit/home/lex.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:15, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/spirit/home/support/attributes_fwd.hpp:43:12: note: ‘boost::spirit::result_of::end’In file included from /usr/local/include/boost/spirit/home/support/info.hpp:17:0, from /usr/local/include/boost/spirit/home/lex/lexer/token_def.hpp:15, from /usr/local/include/boost/spirit/home/lex/lexer.hpp:14, from /usr/local/include/boost/spirit/home/lex.hpp:13, from /usr/local/include/boost/spirit/home/lex/lexer_lexertl.hpp:15, from /usr/local/include/boost/spirit/include/lex_lexertl.hpp:16, from synthax_analyser.cpp:12:/usr/local/include/boost/foreach.hpp:730:1: note: ‘boost::foreach_detail_::end’synthax_analyser.cpp: At global scope:synthax_analyser.cpp:54:1: error: expected declaration before ‘}’ tokenmake: *** [synthax_analyser.o] Error 1 Cordialy,Guillaume Bersac237bis rue de Pessac33000 Bordeaux06.65.30.89.43

5 5

concurrent garbage collector
by Taylor Holliday 23 Jun '13

23 Jun '13

Hey Boost, After struggling with breaking shared_ptr cycles in my app, I wrote a little concurrent garbage collector which uses boost::lockfree::queue. Its actually fairly general purpose, and I've released the code here: https://gist.github.com/wtholliday/5793270 Inspired by my question on stack overflow: http://stackoverflow.com/questions/17116189/concurrent-garbage-collection-f… I'm also working on releasing my unit test... its just quite dependent on other code. For the interface: the basic idea is you have a RootPtr<T> used to manage the collector's root set (please forgive my propensity for CamelCase). You have to explicitly manage references between collectable objects (via AddEdge and RemoveEdge functions), but I think that could be made safe using another smart pointer type which knows the collectable object which owns it. At this point I'm not too concerned about performance, as my object graphs aren't that big. I bet a GC guru could implement this without using a queue of events. Anyway, this is the kind of thing I'd love to see in boost someday, so it would be great to read your opinions of it :-) cheers - Taylor W. Taylor Holliday, Owner/Founder Subatomic Software, San Francisco

3 4

Re: [boost] [Multiprecision] Does MP use references internally?
by Daryle Walker 21 Jun '13

21 Jun '13

Nearly all operators, besides assigning and dereferencing ones, are supposed to return by value. Changing that, even with the “innocuous” (unary)+, is surprising. Daryle W. Sent from Windows Mail From: John Maddock Sent: ‎Thursday‎, ‎June‎ ‎20‎, ‎2013 ‎4‎:‎13‎ ‎AM To: boost(a)lists.boost.org > Is Boost.MP giving users references-to-types instead of class types when > requesting a numeric type? Pointers may be objects in and of themselves, > but references aren't; they're just aliases; trying to intentionally use > them as first-class objects is arguably broken. I don't see why this is a problem, but the first error is coming from: auto const aa = +a, bb = +b; Now, in Boost.Multiprecision the unary operator+ is a noop that returns a reference to self, could that be a cause of the issue?

4 3

ptr_map_adapter::insert non const key argument
by Gaetano Mendola 21 Jun '13

21 Jun '13

Hi, it seems that the method: std::pair<iterator,bool> ptr_map_adapter::insert( key_type& key, mapped_type x ) has the key argument non const? Is there a valid reason for it or it's just a mistake? Regards Gaetano Mendola

3 4

How do I specify no padding bytes within a struct/class?
by Daryle Walker 20 Jun '13

20 Jun '13

I've never done this before, so I'm asking first: how do I specify that a struct/class should have no padding at all, at the start, end, or middle? My classes have internal arrays, and specifying no padding lets users use an array of classX<T> as an array of T (just like C++11 std::complex). Complier-specific answers are OK, as long as I can use preprocessor flags to isolate them. I have a preprocessor flag that's currently set to 0 to indicate that there's no packing. I'll change it to 1 whenever I get a compiler's packing support. Daryle W.

5 7

[Multiprecision] Does MP use references internally?
by Daryle Walker 20 Jun '13

20 Jun '13

This may be an artifact of the compiler's error reporting mechanism, but the errors' expansion of the MultiPrecision type I'm using has reference types in it. Types from Boost.MP seem to be a shell class template that wraps an engine and several options. Some of the errors that pop up when using Boost.MP when using Boost.Test with my custom complex-number class: - Boost.MPL calls within Boost.Test complain that it's trying to get a pointer to a reference. - My own code uses arrays everywhere, and I get errors about making arrays to references. I'm not doing anything (too) advanced. Is Boost.MP giving users references-to-types instead of class types when requesting a numeric type? Pointers may be objects in and of themselves, but references aren't; they're just aliases; trying to intentionally use them as first-class objects is arguably broken. Daryle W.

2 2

Re: [boost] [c++11]
by Niall Douglas 19 Jun '13

19 Jun '13

> I wasn't suggesting making the library strictly C++03-compatible. My main > point was that the library has to be compatible with _todays_ and even better > - _yesterdays_ compilers to be actually useful. My choice of "reasonable" time > frame is 3-5 years, as I mentioned. That includes VS 2008 and VS 2010, which > already had some C++11 features, including rvalue references. Making VS 2013 > absolute minimum is a no-go, IMHO. I don't think anyone is making VS2013 an absolute minimum - rather they're making variadic templates an absolute minimum. Something which any other compiler than VS has had for years, and something which unlike many, if not most other C++11 language features is something which lets you write a ton of stuff you simply can't write without them. Now, nothing in proposed Boost.AFIO uses variadic templates in a way not replaceable with preprocessor programming. However it very /nearly/ did: I had this neato bit of evil variadic instantiation which let you convert an unknown set of trailing args into a std::tuple<> for storage, then /unpack/ said std::tuple<> back into an unknown set of trailing args, all with perfect forwarding. Effectively it was a compile-time std::function<> implementation. As proposed Boost.AFIO is also a closure execution engine where that closure can take arbitrary args and return arbitrary returns, that evil variadic template machinery was really useful because it lets you skip using std::function<> with its implied virtual function call. As proposed Boost.AFIO currently nests, in the worst case scenario, a fully bound std::function<> calling a partially bound std::function<> calling a partially bound std::function<>, that's three nested virtual indirect function calls. Recent Intel CPUs can prefetch and branch predict two nesting levels, but they can't cope with three, so performance takes a real nose dive and hence one of the reasons we currently see a peak 80k IOPS. That evil variadic template machinery gets rid of that problem. And its only replacement is std::function<> - you *cannot* implement that functionality (pure compile time std::function<>) without variadic templates because you can't properly unpack them without. None of this matters for proposed Boost.AFIO. But it certainly matters for the forthcoming C++11 only libraries coming soon to Boost, because they make /very/ heavy usage of functionality only possible with variadic templates. That means that they will require, as an absolute minimum for VS, VS2013 or Nov 2012 CTP. Other C++11 features one can make do without without too much cost, but losing variadic templates means a ton of extra source code complexity, much longer compile times and chopping out a lot of what C++11 enables which simply can't be done in C++03. I suspect that those libraries are probably going to force a new "variadic template support is mandatory" category of Boost libraries, probably sooner rather than later. I agree it's going to be frustrating for those stuck with older compilers: I pity those whose employers force MSVC6 on them to this very day. Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

6 15

Can't compile code with BOOST_LOG_TRIVIAL
by ... ... 19 Jun '13

19 Jun '13

Hi, I am trying to compile this code : #include <boost/log/trivial.hpp> int main(void){ BOOST_LOG_TRIVIAL(trace) << "boost log is working"; return EXIT_SUCCESS;} And I get the following error message : g++ -o test Capture.o ffmpegTools.o FluxVideoModifie.o test.o vizILogger.o -lavformat -lavcodec -lavutil -lswscale -lopencv_core -lopencv_highgui -lboost_filesystem -lboost_log_setup -lboost_log -lz -lpthread -ldl -lm test.o: In function `main':/home/exploit/git/VIZIRD-CAPTURE/proj/capture//test.cpp:39: undefined reference to `boost::log::v2s_mt_posix::trivial::logger::get()'/home/exploit/git/VIZIRD-CAPTURE/proj/capture//test.cpp:39: undefined reference to `boost::log::v2s_mt_posix::trivial::logger::get()'test.o: In function `boost::log::v2s_mt_posix::record::reset()':/usr/local/include/boost/log/core/record.hpp:153: undefined reference to `boost::log::v2s_mt_posix::record_view::public_data::destroy(boost::log::v2s_mt_posix::record_view::public_data const*)'test.o: In function `boost::log::v2s_mt_posix::record boost::log::v2s_mt_posix::sources::basic_composite_logger<char, boost::log::v2s_mt_posix::sources::severity_logger_mt<boost::log::v2s_mt_posix::trivial::severity_level>, boost::log::v2s_mt_posix::sources::multi_thread_model<boost::log::v2s_mt_posix::aux::light_rw_mutex>, boost::log::v2s_mt_posix::sources::features<boost::log::v2s_mt_posix::sources::severity<boost::log::v2s_mt_posix::trivial::severity_level>, void, void, void, void, void, void, void, void, void> >::open_record<boost::parameter::aux::tagged_argument<boost::log::v2s_mt_posix::keywords::tag::severity, boost::log::v2s_mt_posix::trivial::severity_level const> >(boost::parameter::aux::tagged_argument<boost::log::v2s_mt_posix::keywords::tag::severity, boost::log::v2s_mt_posix::trivial::severity_level const> const&)':/usr/local/include/boost/log/sources/basic_logger.hpp:457: undefined reference to `boost::log::v2s_mt_posix::core::get_logging_enabled() const'test.o: In function `~record_pump':/usr/local/include/boost/log/sources/record_ostream.hpp:278: undefined reference to `boost::log::v2s_mt_posix::aux::unhandled_exception_count()'test.o: In function `record_pump':/usr/local/include/boost/log/sources/record_ostream.hpp:259: undefined reference to `boost::log::v2s_mt_posix::aux::stream_provider<char>::allocate_compound(boost::log::v2s_mt_posix::record&)'/usr/local/include/boost/log/sources/record_ostream.hpp:259: undefined reference to `boost::log::v2s_mt_posix::aux::unhandled_exception_count()'test.o: In function `~auto_release':/usr/local/include/boost/log/sources/record_ostream.hpp:243: undefined reference to `boost::log::v2s_mt_posix::aux::stream_provider<char>::release_compound(boost::log::v2s_mt_posix::aux::stream_provider<char>::stream_compound*)'test.o: In function `boost::log::v2s_mt_posix::sources::aux::severity_level<boost::log::v2s_mt_posix::trivial::severity_level>::set_value(boost::log::v2s_mt_posix::trivial::severity_level)':/usr/local/include/boost/log/sources/severity_feature.hpp:135: undefined reference to `boost::log::v2s_mt_posix::sources::aux::get_severity_level()'test.o: In function `boost::log::v2s_mt_posix::record boost::log::v2s_mt_posix::sources::basic_logger<char, boost::log::v2s_mt_posix::sources::severity_logger_mt<boost::log::v2s_mt_posix::trivial::severity_level>, boost::log::v2s_mt_posix::sources::multi_thread_model<boost::log::v2s_mt_posix::aux::light_rw_mutex> >::open_record_unlocked<boost::parameter::aux::tagged_argument<boost::log::v2s_mt_posix::keywords::tag::severity, boost::log::v2s_mt_posix::trivial::severity_level const> >(boost::parameter::aux::tagged_argument<boost::log::v2s_mt_posix::keywords::tag::severity, boost::log::v2s_mt_posix::trivial::severity_level const> const&)':/usr/local/include/boost/log/sources/basic_logger.hpp:260: undefined reference to `boost::log::v2s_mt_posix::core::open_record(boost::log::v2s_mt_posix::attribute_set const&)'test.o: In function `boost::log::v2s_mt_posix::core::push_record(boost::rv<boost::log::v2s_mt_posix::record>&)':/usr/local/include/boost/log/core/core.hpp:308: undefined reference to `boost::log::v2s_mt_posix::core::push_record_move(boost::log::v2s_mt_posix::record&)'collect2: ld returned 1 exit statusmake: *** [test] Error 1 In my makefile I added the links :LIBS_boost = -lboost_filesystem -lboost_log_setup -lboost_log And i have my libraries correctly installed because the command : $ sudo ldconfig -p | grep boost_l display :libboost_log_setup.so.1.53.0 (libc6,x86-64) => /usr/local/lib/libboost_log_setup.so.1.53.0libboost_log_setup.so (libc6,x86-64) => /usr/local/lib/libboost_log_setup.solibboost_log.so.1.53.0 (libc6,x86-64) => /usr/local/lib/libboost_log.so.1.53.0libboost_log.so (libc6,x86-64) => /usr/local/lib/libboost_log.solibboost_locale.so.1.53.0 (libc6,x86-64) => /usr/local/lib/libboost_locale.so.1.53.0libboost_locale.so (libc6,x86-64) => /usr/local/lib/libboost_loc Can you help me please ? Thanks,Guillaume Bersac237bis rue de Pessac33000 Bordeaux06.65.30.89.43

2 1

Weirdness in SVN
by Marshall Clow 19 Jun '13

19 Jun '13

Ok, this is quite worrisome to me. This morning, bug #6136 was reopened: https://svn.boost.org/trac/boost/ticket/6136 This is an "unused variable warning" in Boost.DateTime. I fixed this bug in the trunk: https://svn.boost.org/trac/boost/changeset/80699 I merged this bug fix (and several others) to the release branch: https://svn.boost.org/trac/boost/changeset/80797 But the files (both trunk and release) appear not to contain the change. If I do a "svn diff", the changes appear in the diff, but the file doesn't contain the change. I checked the other files referenced in change set 80797, and they appear to be fine - just this one. Any idea what could be happening here? My only explanation at the moment is that "Subversion is lying to me", and that's both (a) a huge potential problem, and (b) doesn't suggest a course of action. $ svn diff trunk/boost/date_time/format_date_parser.hpp -r 80698 Index: trunk/boost/date_time/format_date_parser.hpp =================================================================== --- trunk/boost/date_time/format_date_parser.hpp (revision 80698) +++ trunk/boost/date_time/format_date_parser.hpp (working copy) @@ -256,7 +256,6 @@ // skip leading whitespace while(std::isspace(*sitr) && sitr != stream_end) { ++sitr; } - charT current_char = *sitr; short year(0), month(0), day(0), day_of_year(0);// wkday(0); /* Initialized the following to their minimum values. These intermediate @@ -290,7 +289,6 @@ } wkday = mr.current_match; if (mr.has_remaining()) { - current_char = mr.last_char(); use_current_char = true; } break; @@ -310,7 +308,6 @@ } wkday = mr.current_match; if (mr.has_remaining()) { - current_char = mr.last_char(); use_current_char = true; } break; @@ -326,7 +323,6 @@ } t_month = month_type(mr.current_match); if (mr.has_remaining()) { - current_char = mr.last_char(); use_current_char = true; } break; @@ -342,7 +338,6 @@ } t_month = month_type(mr.current_match); if (mr.has_remaining()) { - current_char = mr.last_char(); use_current_char = true; } break; @@ -438,7 +433,6 @@ itr++; if (use_current_char) { use_current_char = false; - current_char = *sitr; } else { sitr++; $ svn diff trunk/boost/date_time/format_date_parser.hpp -r 80699 $ -- Marshall Marshall Clow Idio Software <mailto:mclow.lists@gmail.com> A.D. 1517: Martin Luther nails his 95 Theses to the church door and is promptly moderated down to (-1, Flamebait). -- Yu Suzuki

2 3

[range] Best way to count the elements in a filtered range?
by Gonzalo Brito Gadeschi 19 Jun '13

19 Jun '13

I wonder what is the recommended way to count the elements in a filtered range. Let range be a random access range, and filter the result of filtered(predicate), auto filtered_range = range | filter; count_if( filtered_range, [](const&){ return true; }); // (& omitted in lambda) counts the elements in a filtered range. _If_ this is the best way to count the elements in a filtered range, what about defining Range boost::count(Range&& r); to count all element in the range? It could call size() if available and count_if otherwise. Bests, Gonzalo BG

4 7

[mailing list] Duplicated thread - Best way to proceed
by Gonzalo Brito Gadeschi 19 Jun '13

19 Jun '13

The thread: [boost] [range] Best way to count the elements in a filtered range? I sent an email with an unregistered email adress to the list. As expected, I did not receive a confirmation about the mail being accepted. I resent the mail with my registered email adress. As expected, the new mail was accepted. However, the unaccepted mail started getting replies. - What is the best way to proceed? - Why did the email sent with the unregistered email address get replies? - Shouldn't it have been rejected right away? Bests, Gonzalo BG

1 0

[range] Best way to count the elements in a filtered range?
by Gonzalo BG 19 Jun '13

19 Jun '13

I wonder what is the recommended way to count the elements in a filtered range. Let range be a random access range, and filter the result of filtered(predicate), auto filtered_range = range | filter; count_if( filtered_range, [](const&){ return true; }); // (& omitted in lambda) counts the elements in a filtered range. _If_ this is the best way to count the elements in a filtered range, what about defining Range boost::count(Range&& r); to count all element in the range? It could call size() if available and count_if otherwise. Bests, Gonzalo BG

3 2

Is anybody working on the Boost Windows installer?
by Antony Maria Sakkariaz 18 Jun '13

18 Jun '13

Hi, Good morning. I am new to Boost and this mailing list. When I visited BoostPro computing in order to download the Windows installer, I did not see any installer beyond version 1.51. Since BoostPro donated the installer source code to the community, I am checking to see if anybody is updating the installer for the newer Boost versions. In case nobody is working on this, then I thought I would try to do it. :-) Thanks, Antony

2 1

Re: [boost] [c++11]
by Niall Douglas 18 Jun '13

18 Jun '13

> > I should quickly explain why rvalue ref support is so important to proposed > > Boost.AFIO: it's a 100% batch API and therefore takes in batches of things > > to do and returns out batches of results. That implies lots of passing > > sequences of things around in STL containers, which without rvalue refs are > > not cheap to copy. Therefore while we could get the library working on > > Maybe BOOST_ASIO_MOVE_ARG (in boost/asio/detail/config.hpp) will work > for you. I don't understand how that makes std::vector<> or any other STL container suddenly magically start not copy constructing its contents on C++03 compilers. struct async_io_op has both rvalue and const lvalue copy and assignment constructors. It's left up to the compiler and STL container implementation to decide when and where to use them. I agree we should be using more std::move() to help the compiler where it needs it, but all performance tuning is being left till after the Boost import. Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

2 1

Re: [boost] [c++11]
by Niall Douglas 18 Jun '13

18 Jun '13

> 2013/6/14 Sid Sacek <ssacek(a)securewatch24.com>: > <...> > > Sounds like it's not really worth the effort and simply just stick to the old style. > > Stick to the old style. Add #ifndef'ed C++11 specific features if they add > functionality or improve performance much. Boost libraries are tested using > C++11 and C++03 on different compilers and works good in all situations. Speaking of which, I was going to ask this list about the minimum compiler requirements for proposed GSoC Boost.AFIO, so now is as good a time as any. The existing code base being prepared for entry into Boost is pure C++11, or at least as much C++11 as is provided by the Nov 2012 CTP experimental MSVC compiler and therefore easily supported by GCC 4.6 and clang 3.x. The variadic templates used probably can be swapped out easily enough with Boost Preprocessor generators. The very extensive use of C++11 only library features could probably be replaced with Boost equivalents in most cases, though we really do need a fully C++11 functional std::exception_ptr rather than Boost's limited boost::exception_ptr. The thing we probably can't replace without major surgery is rvalue reference usage. It's used very extensively. Moreover, performance without rvalues would truly suck. So here's the question: is C++03 compiler and C++03 TR1 standard library support still an absolute, unnegotiable requirement for a library to become an official part of Boost? Or can we at least require rvalue reference support as a minimum? Or do we add a new category to Boost: some bits of C++11 requiring libraries? We're going to have to do this eventually anyway. Niall

12 20

[multiprecision] Are these types suitable as numeric types for unit tests?
by Daryle Walker 18 Jun '13

18 Jun '13

I'm writing new numeric types, and my unit tests use MPL lists of numeric types. I usually use stuff like int, unsigned, and double, but now I'm adding cpp_int and cpp_dec_float_50. Those types were OK when I was just doing type equalities and sizeof checks. Now I'm doing tests that use objects of those types and I'm getting problems. //==== typedef boost::mpl::list<int, unsigned, cpp_int> test_integer_types; typedef boost::mpl::list<double, cpp_dec_float_50> test_floating_types; //... BOOST_AUTO_TEST_CASE_TEMPLATE( test_complex_component_access1, T, test_integer_types ) { typedef complex_it<T, 0> real_type; typedef complex_it<T, 1> complex_type; real_type a; real_type const & aa = a; complex_type b; complex_type const & bb = b; a[ 0 ] = 6; BOOST_CHECK_EQUAL( a[0], T(6) ); BOOST_CHECK_EQUAL( T(6), aa[0] ); b[ 0 ] = 5; b[ 1 ] = 7; BOOST_CHECK_EQUAL( b[0], T(5) ); BOOST_CHECK_EQUAL( T(5), bb[0] ); BOOST_CHECK_EQUAL( b[1], T(7) ); BOOST_CHECK_EQUAL( T(7), bb[1] ); } //==== I'm getting warnings about integer overflow. The problem is at Line 59 of boost/test/tools/detail/print_helper.hpp. It sets an output stream's precision based on the digits given by std::numeric_limits. //==== BOOST_AUTO_TEST_CASE_TEMPLATE( test_complex_component_access2, T, test_floating_types ) { typedef complex_it<T, 0> real_type; typedef complex_it<T, 1> complex_type; real_type a; real_type const & aa = a; complex_type b; complex_type const & bb = b; a[ 0 ] = 6.0; BOOST_CHECK_CLOSE( a[0], T(6.0), 0.1 ); BOOST_CHECK_CLOSE( T(6.0), aa[0], 0.1 ); b[ 0 ] = 5.5; b[ 1 ] = -7.0; BOOST_CHECK_CLOSE( b[0], T(5.5), 0.1 ); BOOST_CHECK_CLOSE( T(5.5), bb[0], 0.1 ); BOOST_CHECK_CLOSE( b[1], T(-7.0), 0.1 ); BOOST_CHECK_CLOSE( T(-7.0), bb[1], 0.1 ); } //==== This time it's an error, at Line 59 of boost/test/tools/floating_point_comparison.hpp. There no (close enough) matching function for "fpt_abs" from some "boost::multiprecision::detail::expression<..." type. (It was truncated by the display. I don't know how to get a clean print-out of errors from Code::Blocks.) I'm guessing the expression template setup is screwing things up. Daryle W.

6 25

Re: [boost] [c++11]
by Niall Douglas 17 Jun '13

17 Jun '13

> > We can work around the lack of variadic templates, and therefore > > support vanilla VS2012 if peer review demands it. Of course VS2012 > > won't make binaries which can run on Windows XP :( so maybe VS2010 > > support will also be demanded by peer review. If it is, we'll do what is required > to meet VS2010. > JFYI: the VS2012 Update 1 can build binaries which can run on WinXP. You just > need to specify the v110_xp toolset in the project options. Apologies, I had skim read the VS2012 update announcement when it happened where it used the phrase "This new platform toolset points to a repackaged version of the Windows 7 SDK shipped in Visual Studio 2010 instead of the Windows 8 SDK" but I had missed the phrase "but uses the same Visual Studio 2012 compiler". As a result, I thought they had basically packed up the VS2010 build environment for VS2012 and that they therefore were equivalent. Mea culpa. BTW, and purely for information, I found that if you build your VS2012 Nov 2012 CTP app as a DLL, and then write a tiny shim program in VS2010 which loads in that DLL, all appeared to work okay on Windows XP. I didn't test that hugely at the time, but it did work for me to get variadic template capable MSVC binaries running on XP. Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

1 0

[New][Multiprecision] Getting errors while writing hypercomplex classes.
by Daryle Walker 17 Jun '13

17 Jun '13

I've banged out (yet another) complex number class at <https://github.com/CTMacUser/Complex>. The current commit has an SHA of "b866cda91ccdb4aa87c199c6d9e7c776fee61bcc." Right now, I'm writing this code on a 32-bit Windows 8 system using Code::Blocks with a packaged MinGW GCC 4.7 by TDM. In many of the incremental changes, I ran into internal compiler errors. I don't know if my code is too unusual or it's the compiler. I'm asking if you guys can check out the code with other compilers (GCC 4.7 besides MinGW/TDM, GCC 4.8, Clang 3.x, non-Windows, etc.) so we can figure out what bug goes where. There are two class templates: - boost::math::complex_it<Number, Rank> - boost::math::complex_rt<Number, Rank> "Number" is a Regular type that supports math operations plus Boolean conversions. "Rank" is the Cayley-Dickson hypercomplex level. Use 0 as a shell for real numbers, 1 for regular complex numbers, 2 for quaternions, 3 for octonions, etc. The "complex_it" class template stores all the components directly in an array with length 1ULL << Rank ("i" is for "iterative"). The "complex_rt" class template stores an array of 2 objects of the previous level ("r" is for "recursive"), except for the partial-specialized base case which stores one component. The two templates support nearly the same interface. - Static interface * using value_type = Number * rank = Rank * static_size = 1ULL << Rank * using barrage_type = complex_?t<Number, Rank - 1> (or self when Rank == 0) - Construction * Complex_type a; // random garbage bits * Complex_type b{}; // zero-fill * Complex_type c{ r }; // real conversion * Complex_type d{ r, i, ... }; // real list * Complex_type e{ Complex_type<ConvertibleNumber, SameOrLowerRank>, ... }; * Complex_type f{ Complex_type<ConvertibleNumber, GreaterRank> }; // explicit * Complex_type g{ Other_complex_type<AnyNumber, AnyRank> }; // explicit * Complex_type h{ Complex_type<AnyNumber, AnyRank> }; // explicit * For [d], the total number components can't exceed static_size. * For [e], the combined number of components from the objects can't exceed static_size. * "ConvertibleNumber" uses implicit conversion, "AnyNumber" static_cast. * Conversions in [g] are both in complex_rt, a constructor and conversion-operator. * For [h], it excludes types in "AnyNumber" that would be covered by [e] and [f]. - Member functions * Boolean conversion operator (explicit) * "real" and "imag," inspector and mutator versions, just like std::complex (Don't use "imag" mutator when Rank == 0!) * "unreal" inspector, like boost::quaternion and octonion; plus a mutator version * Lower- and upper-halves of component list (called barrages) - complex_it uses inspector and mutator, like real/imag/unreal - complex_rt uses by-reference returns, const and mutable * operator [] for direct (by-reference) access to components - External operators * == * != * + (unary) * - (unary) * ~ (new, conjugation) * << (output) - Tuple interface (get, tuple_element, tuple_size) - Object support * begin (non-member, complex_it only) * end (non-member, complex_it only) * swap - Math * conj These spots cause internal-compiler errors: * https://github.com/CTMacUser/Complex/blob/master/include/boost/math/complex_ it.hpp#L753 * https://github.com/CTMacUser/Complex/blob/master/include/boost/math/complex_ rt.hpp#L593 * https://github.com/CTMacUser/Complex/blob/master/include/boost/math/complex_ rt.hpp#L599 use the comments to switch the code back and see if it works on your system. There were also problems using Boost.Multiprecision in the unit tests. I don't know if the problems are in Multiprecison, Test, MPL, or some interaction between them. The spots in "complex_it_test.cpp" and "complex_rt_test.cpp" that use the "test_builtin_types" alias were supposed to use "test_types," but the sample types from Multiprecision had MPL errors. Switch the types and see if they work on your system. Daryle W.

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Re: [boost] [c++11]
by Niall Douglas 17 Jun '13

17 Jun '13

> > Actually it targets three compilers (+clang). I might add that > > Boost.ASIO only officially supports Windows, Linux, Solaris and OS X, > > and only the compilers MSVC7.1 or later and g++ 3.3 or later. Some > > would say that is a fairly narrow set in itself. > > That's not quite what I read here: > > http://www.boost.org/doc/libs/1_53_0/doc/html/boost_asio/overview/implem > entation.html See for yourself at http://www.boost.org/doc/libs/1_53_0/doc/html/boost_asio/using.html. I agree that perhaps that list, given the list you linked to, is now out of date. > And the compilers you mentioned as officially supported by ASIO actually cover > pretty much every compiler out there nowdays. > > Comparing that with your requirement of the compiler that has not even been > released, it doesn't look like AFIO portability level will be even remotely close to > that of ASIO. We can work around the lack of variadic templates, and therefore support vanilla VS2012 if peer review demands it. Of course VS2012 won't make binaries which can run on Windows XP :( so maybe VS2010 support will also be demanded by peer review. If it is, we'll do what is required to meet VS2010. > > Given that we knew that VS2012 would get variadic templates later this > > year (which it will in the form of VS2013), we decided to just go > > ahead with what > > C++11 features will be available to > 90% of C++ users by the end of 2013. > > That surely should satisfy the portability requirement, if not, then > > we'll work backwards until we reach > 95% of C++ users or > 99% if > > Boost peer review really, really wants it. > > I think your estimate of "> 90% of C++ users by the end of 2013" is much too > optimistic. People in corporate sector are very reluctant to update their > toolsets, so expect people trying to use your new library with 3-5 year old > compilers. I used the qualifier "available to" with purpose: I agree that a compiler may be available to > 90% of C++ users but for whatever reason those users do not avail of that compiler. FYI for my other open source I still get regular bug submissions for MSVC6 breakage due to my use of C++98 features, so I'm well aware what corporate is like. That said, this is a new greenfield library, and therefore no legacy compiler technology is inconvenienced by its compiler requirements. I might add that as C++ Now 2013 showed, there are quite a few new Boost libraries on their way which are C++11 only and will only ever be C++11 only: I saw presentations on new C++11 only versions of Boost.Proto and Boost.Spirit for example. > I know, C++11 has many fancy features and all, and I'm all for its adoption too. > But Boost also serves practical purpose, and if people can't use your library then > that just limits its usefulness. So unless you trying to make some academic work > here, the library should be more portable. If a corporate end user really, really wants the library working on their compiler toolset, they are always free to sponsor a port to that toolset. It's all open source. Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

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Re: [boost] [c++11]
by Niall Douglas 17 Jun '13

17 Jun '13

> > The existing code base being prepared for entry into Boost is pure > > C++11, or at least as much C++11 as is provided by the Nov 2012 CTP > > experimental MSVC compiler and therefore easily supported by GCC 4.6 and > clang 3.x. > > I hope that you do realize that the Nov12 CTP does not come with a go-live > license, nor is recommended for any human consumption. Meh. First preview of VS2013 is only a month away. Nov 2012 CTP is usefully broken in ways easy to work around (parser bugs) rather than broken in unhelpful ways (unreliable code generation). It fills a useful slot until VS2013 arrives later this year. > It seems quite odd to me to spend significant GSoC resources on making a library > that targets only two compilers, and assumedly a rather narrow set of OSes. Actually it targets three compilers (+clang). I might add that Boost.ASIO only officially supports Windows, Linux, Solaris and OS X, and only the compilers MSVC7.1 or later and g++ 3.3 or later. Some would say that is a fairly narrow set in itself. We'll be matching Boost.ASIO's official platform support, but adding official support for FreeBSD 10 with clang and libcxx. In truth though it ought to work on any OS providing a POSIX file i/o API with preadv() and pwritev() which is the majority (including Windows via its MSVCRT incidentally). You may find https://github.com/BoostGSoC/boost.afio/wiki/Status-of-proposed-Boost.AFIO of interest. There it tells you how to get started with the proposed library right now. > Was this C++11-only requirement part of the original project plan, and why > didn't anyone object to it then? Yes, it was an original plan requirement. Having full fat C++11 (esp. the C++11 standard library) to hand made the code and design *very* considerably simpler and *much* easier to read (and therefore maintain) - in fact, there is only 670 lines of active code. Judging from the presentations at C++ Now 2013, this simplification experience of pure C++11 is hardly unique: many presenters commented on just how much their pure C++11 new versions of Boost libraries were cleaner, simpler, faster to compile and faster performance, and hugely more maintainable. Given that we knew that VS2012 would get variadic templates later this year (which it will in the form of VS2013), we decided to just go ahead with what C++11 features will be available to > 90% of C++ users by the end of 2013. That surely should satisfy the portability requirement, if not, then we'll work backwards until we reach > 95% of C++ users or > 99% if Boost peer review really, really wants it. Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

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Re: [boost] [c++11]
by Niall Douglas 17 Jun '13

17 Jun '13

> > On 14 June 2013 17:21, Niall Douglas <ndouglas(a)blackberry.com> wrote: > >> So here's the question: is C++03 compiler and C++03 TR1 standard > >> library support still an absolute, unnegotiable requirement for a > >> library to become an official part of Boost? > > > > No. > > > > http://www.boost.org/development/requirements.html#Portability > > I suspect this may come down to the review ultimately: I can imagine that any > library that was C++11 only would have a hard time getting through review "as > is", *unless* there's a really compelling reason for it to be that way (and for > some libraries that may well be the case). However, I can also imagine a library > being developed as a C++11 only lib and only ported back to C++03 and/or less > capable compilers once it's stable (or vice versa). Thanks John: you're the only one who actually answered my question. I should quickly explain why rvalue ref support is so important to proposed Boost.AFIO: it's a 100% batch API and therefore takes in batches of things to do and returns out batches of results. That implies lots of passing sequences of things around in STL containers, which without rvalue refs are not cheap to copy. Therefore while we could get the library working on C++03, I'd imagine max IOPS would be awful as all those container copy constructors fire several times per API invocation. Right now max IOPS is about 80,000 which is awful, and that's *with* C++11. I'd expect that to be an order of magnitude slower without move construction. Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

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Re: [boost] [c++11]
by Niall Douglas 17 Jun '13

17 Jun '13

> I'll be blunt here: taking off my corporate job hat and putting back on my old > consulting hat, I'd say it simply: you'll get ~ 90% of the C++ user base support > from my open source code for free. If you want more for your niche technology > Y, my rates start at $200/hour. I misphrased myself here: nothing in this statement should be taken as meaning that I am available for consulting work at any hourly rate since I began employment at BlackBerry, and my consulting firm is indeed closed for new business with no prospect of reopening in the immediate future. I meant my original statement in the sense that wanting compatibility with some technology Y is something which can't be expected for free in open source. That includes legacy compilers. Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

1 0

Re: [boost] [c++11]
by Niall Douglas 17 Jun '13

17 Jun '13

> That depends on what you consider supported by Boost. A lot of the > courtesy support for the native compilers for many OSes out there seems > to be dying out. If I may be blunt though, if big libraries like Boost don't show up vendor provided compilers as falling short on standards compliance, then there is very little incentive for those vendors to fix their compilers. In other words, it goes both ways. > I used to see Boost as an empowering library, enhancing and evening out > the playing field among the compilers out there. > > Some seem to see it as a playground to gain recognition and fast-track > things into the coming standard libraries, instead of producing > something usable in the real world. > > I guess it's losing the goal and aim I perceived, if it ever had it to > begin with. To me, it feels like a betrayal from the library I have > spent many manhours supporting. > > I've been on this rant before on the lists, in the big sprawling > discussions about the feasibility of a Boost 2.0, but it seems nothing > was learned then, and I don't expect anything to be learned going > forward either. > > As for limiting Boost authors, for leaf libraries that end users can > avoid, sure, there might not be too much harm. It's creeping into the > very core libraries as well, which _does_ bother me, as it can render > whole swaths of the library utterly unusable. > > In the end, we need a definitive statement from whatever cabal is > controlling Boost, so we don't get these kinds of discussion > resurrections every few months. All this causes is a lack of faith in > the project. Equally, it's not like Boost is hugely commercially developed like other open source projects: it's mostly volunteer driven. And it's real tough to come along to people's free time and tell them they have to target compilers written more than a decade ago, and if they don't their commits won't be allowed or will get rolled back. I'll be blunt here: taking off my corporate job hat and putting back on my old consulting hat, I'd say it simply: you'll get ~ 90% of the C++ user base support from my open source code for free. If you want more for your niche technology Y, my rates start at $200/hour. Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

1 0

Migrating www.boost.org to another server
by DongInn Kim 17 Jun '13

17 Jun '13

Hi, The CREST is planning to move all the boost services that OSL/CREST has provided to another server. All the services in the current OSL/CREST server are: - Web services: www.boost.org boostcon.boost.org svn.boost.org/svnmanager svn.boost.org/trac/boost beta.boost.org - Subversion, trac, and SVNManager - Mailinglist mailman hypermail First, we would like to migrate www.boost.org and beta.boost.org which are not dependent on any other services and domains at all. The data of www.boost.org and beta.boost.org can be simply moved but I need someone's help who can switch the domain record to make these two hostnames point to the new server. Who can I talk to about this domain migration? I will setup another schedule for the next migrations and I do not have any particular lists yet but probably the rest of web services and Subversion would be the candidate. We will see. Regards, -- - DongInn

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[phoenix] Using Phoenix lambdas on top of custom Proto expressions
by Denis Demidov 17 Jun '13

17 Jun '13

Hello, I am working on VexCL (https://github.com/ddemidov/vexcl) - a vector expression template library for OpenCL. I have recently added support for automatic generation of OpenCL kernels from generic functors (description of the feature: https://github.com/ddemidov/vexcl#function-generator) In order to implement this, I pass the instances of vex::symbolic<T> class to the given functor. vex::symbolic<T> dumps to output stream any arithmetic operations it is being subjected to, and that's how I am able to construct the OpenCL kernel source. The symbolic<T> class is of course a Boost.Proto terminal. Now, it seems natural to use Boost.Phoenix to provide the generic functors for the function generator. And indeed it is possible with simple expressions (see https://github.com/ddemidov/vexcl/blob/a95dfdd68/tests/generator.cpp#L124) However, if I try to bring cmath functions overloads from <boost/phoenix/stl/cmath.hpp> and use those ( https://github.com/ddemidov/vexcl/commit/b95da14e51) I get compilation errors. The reason apparently is that boost::phoenix_impl::<function>_impl assumes that result of <function>(expr) has the same type as expr itself. This of course is not true if expr is a Boost.Proto expression. Everything works as intended with the following patch: --- a/cmath.hpp +++ b/cmath.hpp @@ -25,11 +25,11 @@ namespace boost { struct result<This(BOOST_PHOENIX_A(n))> \ { \ typedef \ - typename proto::detail::uncvref<A0>::type \ + decltype( name(typename proto::detail::uncvref<A0>::type()) ) \ type; \ }; \ template<BOOST_PHOENIX_typename_A(n)> \ - A0 operator()(BOOST_PHOENIX_A_const_ref_a(n)) const { \ + auto operator()(BOOST_PHOENIX_A_const_ref_a(n)) const -> decltype( name(BOOST_PHOENIX_a(n)) ) { \ using namespace std; \ return name(BOOST_PHOENIX_a(n)); \ } \ I understand this is unacceptable in its current form (because it uses c++11 features), but I could not do this in terms of e.g. boost::result_of. May be someone has a better idea of how to implement this? -- Best regards, Denis

1 0

[thread] Use of synchronized_value<> member in a constructor
by Klaim - Joël Lamotte 17 Jun '13

17 Jun '13

I am using now Boost 1.54.0 Beta (r84749). I am writting code similar to the following (but a bit more complex) : struct SequenceInfo { SequenceId id; ProjectId project_id; std::string name; //.... }; class Sequence { boost::synchronized_value<SequenceInfo> m_info; public: explicit Sequence( SequenceId new_id, SequenceInfo info ) : m_info( std::move(info) ) { m_info->id( new_id ); // mutex lock } // ... }; My current understanding of concurrent access practice is that it is not necessary to use synchronization mechanisms associated to member objects manipulated into a constructor, because it can happen on only one thread. If I am correct, then the lock of the synchronized_value is unnecessary. I suspect that there might be other cases like this one where the object responsable for the synchronized object should be able, rarely, to access the object unsafely. Suggestion: add an unsafe access to the object, in a very visible way. m_info.unsafe_access().id( new_id ); OR m_info.unsafe_access()->id( new_id ); // using a smart pointer which checks if safe accesses have been done inbetween and throw if it is the case? or any other checks detecting potential error It looks like it would allow avoiding cost where it could be avoided using a mutex manipulated manually. Any thoughts on this? Joel Lamotte

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[1.54] [thread] MSVC build broken
by Andrey Semashev 16 Jun '13

16 Jun '13

Hi, I've noticed that my Boost.Log tests on MSVC are failing massively. The build log hints that Boost.Thread might be the culprit, and its tests are also failing on MSVC with the following error: ..\boost/thread/future.hpp(1127) : error C2248: 'boost::unique_lock<Mutex>::operator =' : cannot access private member declared in class 'boost::unique_lock<Mutex>' with [ Mutex=boost::mutex ] ..\boost/thread/lock_types.hpp(110) : see declaration of 'boost::unique_lock<Mutex>::operator =' with [ Mutex=boost::mutex ] This is happening on release branch. Could this be fixed?

4 10

[test] resolution of test time information
by Alexander Kjäll 16 Jun '13

16 Jun '13

Hi I'm new to the boost test library and it seems to fill my needs of a testing framework quite well. One thing that i haven't managed to figure out is if it's possible to increase the resolution of the timekeeping information, it currently seems to be reported with a resolution of 10 milliseconds. Is it possible to reduce that somehow? best regards Alexander Kjäll

1 0

[c++11]
by Sid Sacek 15 Jun '13

15 Jun '13

This was probably discussed many times already, but I seem to not have been paying close enough attention. Maybe someone can point me to the discussions in the archives... With all of the cool new language features of C++11, am I correct in assuming that boost library developers have no real opportunity to use any of it in order to be backwards compliant with all the older standard? I realize there are many boost equivalents already in place, but when would it become permissible to use native C++11 syntax? Thanks, -Sid

7 8

[optional][thread] Returning a future in an optional fails
by Klaim - Joël Lamotte 14 Jun '13

14 Jun '13

I just hit this using VS2012/boost 1.54 beta. #include <boost/optional.hpp> #include <future> boost::optional< std::future<void> > top() { return std::async( []{ int i=0; ++i; } ); } int main() { auto opt = top(); } Error: 1>E:\Projects\SDK\boost\boost\include\boost-1_54\boost/optional/optional.hpp(347): error C2248: 'std::future<void>::future' : cannot access private member declared in class 'std::future<void>' 1> C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\include\future(1238) : see declaration of 'std::future<void>::future' 1> C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\include\future(1200) : see declaration of 'std::future<void>' 1> E:\Projects\SDK\boost\boost\include\boost-1_54\boost/optional/optional.hpp(346) : while compiling class template member function 'void boost::optional_detail::optional_base<T>::construct(const std::future<void> &)' 1> with 1> [ 1> T=std::future<void> 1> ] 1> E:\Projects\SDK\boost\boost\include\boost-1_54\boost/optional/optional.hpp(231) : see reference to function template instantiation 'void boost::optional_detail::optional_base<T>::construct(const std::future<void> &)' being compiled 1> with 1> [ 1> T=std::future<void> 1> ] 1> E:\Projects\SDK\boost\boost\include\boost-1_54\boost/optional/optional.hpp(501) : see reference to class template instantiation 'boost::optional_detail::optional_base<T>' being compiled 1> with 1> [ 1> T=std::future<void> 1> ] 1> E:\Projects\Art_Of_Sequence\repos\aos-all\tool\aosdesigner\backend\test\workspace.cpp(30) : see reference to class template instantiation 'boost::optional<T>' being compiled 1> with 1> [ 1> T=std::future<void> 1> ] I also tried with http://coliru.stacked-crooked.com/ gcc4.8 (but I don't know the boost version) and got a similar error. I first hit this with boost::future but it don't seem to be the problem as it generate the same error. My question is: does std/boost::future don't match the requirements to be an optional value? Or is this an error I should log? Joel Lamotte

2 1

link to old TR1 draft on boost.org
by Jonathan Wakely 14 Jun '13

14 Jun '13

The Boost home page links to http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1745.pdf but that draft was replaced by N1836.

2 1

Future of Boost.Signals
by Marshall Clow 13 Jun '13

13 Jun '13

Doug Gregor has indicated to me that he is not able to continue with the development/maintenance of Boost.Signals. [ This is not a surprise, the last significant change to the library was back in 2004. ] Fortunately, Frank Hess' Signals2 library is going strong, and he has a porting guide for people currently using Boost.Signals at: http://www.boost.org/doc/html/signals2/api_changes.html#signals2.porting For the upcoming 1.54 release, I have added notes to this effect to the Boost.Signals documentation, and added a warning to <boost/signals.hpp>. The warning states: Boost.Signals is no longer being maintained and is now deprecated. Please switch to Boost.Signals2. To disable this warning message, define BOOST_SIGNALS_NO_DEPRECATION_WARNING Note: There have been no code changes to Boost.Signals. All code that uses it will continue to work. -- Marshall Marshall Clow Idio Software <mailto:mclow.lists@gmail.com> A.D. 1517: Martin Luther nails his 95 Theses to the church door and is promptly moderated down to (-1, Flamebait). -- Yu Suzuki

1 0

Tips to fix boost::asio::windows::random_access_handle which is seriously broken
by Niall Douglas 13 Jun '13

13 Jun '13

Dear Boost, The forthcoming GSoC Boost.AFIO library has found a problem with boost::asio::windows::random_access_handle in that it appears to clamp buffer sizes to 64Kb and not increment overlapped offsets during multi-buffer reads and writes, and which is reported at https://svn.boost.org/trac/boost/ticket/8669. These are desirable features for network i/o, not so for file i/o. As my work on the existing code base which Paul is porting to Boost is now complete and purring beautifully on POSIX, I'm thinking I might as well go fix the Boost.ASIO Windows IOCP problem. Before I begin, can I ask here if anyone else has done some work on this topic from which I might be able to borrow? The thread at http://comments.gmane.org/gmane.comp.lib.boost.asio.user/3676 suggests that if I use async_write_some() then I can bypass the 64Kb clamp using "my own completion condition". I'm thinking that boost::asio::windows::random_access_handle really ought to actually implement random access, so rather than hacking around the problem, fixing boost::asio::windows::random_access_handle is better. My thanks in advance, Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

1 0

[Multiprecision] High-performance radix-2 floating-point back-end
by Aditya Jain 13 Jun '13

13 Jun '13

Hi This is my first post on the mailing list , so apologies if it doesn't follow any of the protocols. I was looking at GSoC projects this year for Boost and I am wondering if someone is working on a high-performance radix-2 floating-point back-end for Boost.Multiprecision. If not , I would be interested in doing this project .I am currently a Masters student interning at a tech company in Seattle but I would be able to devote 15-20 hours a week for this project. I have a fairly good background in C++ and numerical programming.So in case no else is working on it (for GSoC or otherwise ) , I would be really interested . If someone is already working on it, I would be interested in some other projects I could potentially work on . Looking forward to a reply. Regards -- Aditya Jain MS Computer Science (Machine Learning Track) Columbia University B.Tech, IIT Roorkee

4 4

ATTN: Boost GSoC mentors and students: Continuous Integration for GSoC thoughts
by Niall Douglas 11 Jun '13

11 Jun '13

Dear Boost, I spent the weekend experimenting with getting CI set up for the async file i/o library which will hopefully become Boost.AFIO through Paul's GSoC. I tried a number of free-for-open-source CI providers which integrate tightly with GitHub, and eventually settled with Travis CI. You can see the last commit CI results at https://travis-ci.org/ned14/TripleGit. As much as Travis CI has a primitive and clunky UI, unlike the other CIs it's based on snapshotting VMs with root privs which gives you unparalleled flexibility for testing config, so I was able to configure this to happen with each and every git push to github: 1. Test that code builds with GCC 4.6 and clang 3.2. 2. Test that unit and functional tests execute without error when built with GCC 4.6 and clang 3.2. 3. Run unit and functional tests with valgrind --tool=memcheck and test that no memory errors nor memory leaks occur with binaries built with GCC 4.6 and clang 3.2. 4. Install GCC 4.8 and compile everything using -fsanitize=thread (i.e. instrument using the port of clang's ThreadSanitizer v2 to GCC), then execute a full set of unit and functional tests looking for race conditions and if any, fail. You'll note I've marked that test as allowed to fail, because Boost v1.53 has a number of known race conditions when used as C++11 which are hopefully fixed in v1.54 :) Personally speaking, I think this depth and degree of CI is *invaluable* to modern software development practice. So the question becomes: are the Boost GSoC mentors and students interested in setting up CI for this year's GSoC projects, or at least the ones hosted on github at https://github.com/BoostGSOC? In case you're wondering how hard it is to set up Travis CI for your github project, you just need one file called .travis.yml. You can see the one I wrote at https://github.com/ned14/TripleGit/blob/master/.travis.yml. Thoughts? Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

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[utility] [assert] Proposal for a new assert macro which stores the failed values ("informative assert")
by Viktor Sehr 11 Jun '13

11 Jun '13

I'd like some opinions about this assert implementation which I'd like to propose as an update of the old BOOST_ASSERT. Basically it stores the failed values next to the expression string, instead of just the expression string: "INFORMATIVE_ASSERT(5*5 < 2*2);" "5*5 < 2*2 | 25 | 4" "INFORMATIVE_ASSERT(std::vector<int>(10).size() == std::vector<int>(12).size());" "std::vector<int>(10).size() > std::vector<int>(12).size() | 10 | 12" Notes - If the class can't be serialized, the byte-data is logged instead. - It writes the values to the expression string in order to be compliant with any assert implementations Easy to read implementation available here: https://docs.google.com/file/d/0B69BCPzak52DcnF5dmhRRno3V2M/edit?usp=sharing Modified version of BOOST_ASSERT available here: https://docs.google.com/file/d/0B69BCPzak52DZW1oX1AtREM4eVU/edit?usp=sharing /Viktor (Reposting this as I posted it without labels one week ago)

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Re: [boost] [1.54.0] Beta 1 Available
by Cromwell Enage 11 Jun '13

11 Jun '13

Hi, all. When calling the merge() member function of a boost::heap::d_ary_heap, is the heap passed in not supposed to be emptied? Here's my test program: ['' #include <boost/heap/d_ary_heap.hpp> #include <boost/heap/binomial_heap.hpp> #include <boost/heap/fibonacci_heap.hpp> #include <boost/heap/pairing_heap.hpp> #include <boost/heap/skew_heap.hpp> #include <boost/test/minimal.hpp> template <typename Heap> void test_heap_merge_memfun() { Heap heap_1, heap_2; heap_1.push(3); heap_1.push(5); heap_1.push(1); heap_2.push(2); heap_2.push(4); heap_2.push(0); heap_1.merge(heap_2); std::cout << " heap_2"; if (!heap_2.empty()) { BOOST_CHECK(4 == heap_2.top()); heap_2.pop(); BOOST_CHECK(2 == heap_2.top()); heap_2.pop(); BOOST_CHECK(0 == heap_2.top()); heap_2.pop(); std::cout << " not"; } std::cout << " emptied." << std::endl; BOOST_CHECK(heap_2.empty()); BOOST_CHECK(5 == heap_1.top()); heap_1.pop(); BOOST_CHECK(4 == heap_1.top()); heap_1.pop(); BOOST_CHECK(3 == heap_1.top()); heap_1.pop(); BOOST_CHECK(2 == heap_1.top()); heap_1.pop(); BOOST_CHECK(1 == heap_1.top()); heap_1.pop(); BOOST_CHECK(0 == heap_1.top()); heap_1.pop(); BOOST_CHECK(heap_1.empty()); } int test_main(int argc, char** argv) { test_heap_merge_memfun< boost::heap::d_ary_heap< int , boost::heap::arity<4> , boost::heap::mutable_<true> > >(); test_heap_merge_memfun<boost::heap::binomial_heap<int> >(); test_heap_merge_memfun<boost::heap::fibonacci_heap<int> >(); test_heap_merge_memfun<boost::heap::pairing_heap<int> >(); test_heap_merge_memfun< boost::heap::skew_heap<int,boost::heap::mutable_<true> > >(); return 0; } ''] When I run this program, I see that all the other heap types empty the heap passed in. I use gcc 4.2.1 with Apple clang version 4.0 on MacOSX 10.8 Cromwell D. Enage

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[parameter] BOOST_PARAMETER_CONSTRUCTOR bug
by James Hirschorn 10 Jun '13

10 Jun '13

I've already submitted a bug report, but I'm also posting it here in case anyone has more info. ------------- The following variation on the example from the boost::parameter tutorial, where the required parameter is changed to optional, fails to compile. myclass_impl is being passed an empty argument list. #include <iostream> #include <boost/parameter.hpp> BOOST_PARAMETER_NAME(name) BOOST_PARAMETER_NAME(index) struct myclass_impl { template <class ArgumentPack> myclass_impl(ArgumentPack const& args) { std::cout << "name = " << args[_name] << "; index = " << args[_index] << std::endl; } }; struct myclass : myclass_impl { BOOST_PARAMETER_CONSTRUCTOR( myclass, (myclass_impl), tag , (optional (name, *) (index, *) ) ) // no semicolon }; int main(int argc, char * argv[]) { myclass C(_name="hello", _index=0); }

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[type_erasure] Compilation time
by Felipe Magno de Almeida 10 Jun '13

10 Jun '13

Hello Steven, Is there anyway to not include some definitions in header to delay instantiation for use with explicit template instantiations in specific translation units with type_erasure? I have a CORBA library which uses type_erasure for each interface defined in IDL. The problem is that if I include too many #include's for the precompiled headers which use type_erasure, then the compiler ends up consuming too much memory (>10GB), which makes it unfit for 32bit compilers which can use at most 3GB. Regards, -- Felipe Magno de Almeida

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Re: [boost] [multiprecision] Are these types suitable as numeric types for unit tests?
by Daryle Walker 09 Jun '13

09 Jun '13

-----Original Message----- From: John Maddock Sent: Saturday, June 08, 2013 4:40 AM >> I'm getting warnings about integer overflow. The problem is at Line >> 59 of boost/test/tools/detail/print_helper.hpp. It sets an output >> stream's precision based on the digits given by std::numeric_limits. > >That's harmless but annoying: it's because std::numeric_limits<cpp_int>::digits is >INT_MAX. The stream precision isn't ever used by integer types anyway... I switched to one of the fixed-sized types (512 bits). >> This time it's an error, at Line 59 of >> boost/test/tools/floating_point_comparison.hpp. There no (close >> enough) matching function for "fpt_abs" from some >> "boost::multiprecision::detail::expression<..." type. (It was >> truncated by the display. I don't know how to get a clean print-out >> of errors from >> Code::Blocks.) I'm guessing the expression template setup is screwing >> things up. > >Yes, it's because Boost.Test can't be used with expression template enabled types. >It's a known issue, and I've added a patch for this: >https://svn.boost.org/trac/boost/ticket/8272, but Genediiy seems to be MIA at present :-( > >Do you particularly want to test with expression-template enabled types (I reaslise >there are cases when you do)? If not then you could use multiprecision types that >have expression templates turned off and that should fix things. I switched to the same type with expression-templates turned off. Daryle W.

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[range] [extensions] Default values for range access adaptors?
by Viktor Sehr 09 Jun '13

09 Jun '13

I'd like to suggest the addition of a default value to the range access adaptors. Either by adding it as an extra, non-necessary parameter for the functions, or by duplicating the functions as "front_or_default(T default value)". For example it would be useful for finding objects which I am not sure exists in a range. std::vector<int> vec = boost::assign::list_of(2)(4)(6); auto first_odd = vec | filtered(is_odd) | front(); // undefined? auto first_odd = vec | filtered(is_odd) | front_or_default(-1); // everything is fine! Another option would be a function which returns the adress, or nullptr if the value does not exist? /Viktor

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boost.range bug in transformed or sliced
by John Reid 09 Jun '13

09 Jun '13

Suppose you wish to transform and slice a random access range. Surprisingly the order in which you apply the operations makes a big difference to performance. I'm guessing this is not desired behaviour, correct me if I'm wrong. AFAICT when transforming happens before slicing the iterators involved in the internals of boost.range are being treated as forward iterators not random access iterators. An advance() operation is made on one of the iterators with a negative number and this advance is O(n) for forward iterators but O(1) for random access. The code below demonstrates (adapted from sliced example code). On an unrelated note the documentation for transformed does not mention that the function is part of the range return type. It is given as: boost::transformed_range<typeof(rng)> Code to demonstrate the transform then slice problem: #include <boost/range/adaptor/transformed.hpp> #include <boost/range/adaptor/sliced.hpp> #include <boost/range/algorithm/copy.hpp> #include <boost/assign.hpp> #include <iterator> #include <iostream> #include <vector> #include <functional> struct identity { typedef int result_type; result_type operator()( int i ) const { return i; } }; int main(int argc, const char* argv[]) { using namespace boost::adaptors; using namespace boost::assign; std::vector< int > input; input += 1,2,3,4,5,6,7,8,9; // slicing then transforming my iterator range std::cout << "Sliced then transformed: "; boost::copy( input | sliced( 2, 8 ) | transformed( identity() ), std::ostream_iterator< int >( std::cout, ",") ); std::cout << "\n"; // transforming then slicing my iterator range - takes a very long time.... std::cout << "Transformed then sliced: "; boost::copy( input | transformed( identity() ) | sliced( 2, 8 ), std::ostream_iterator< int >(std::cout, ",")); std::cout << "\n"; return 0; }

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merge of interface modification?
by Oliver Kowalke 09 Jun '13

09 Jun '13

Do I get permission to merge a change in the interface of boost.coroutine into release?

2 3

[Boost.Test] Error with "putenv" when using (1.53) release branch
by Daryle Walker 07 Jun '13

07 Jun '13

This happened to me a few months ago when trying out a Windows 8 compiling setup with Code::Blocks. I pointed to the release branch of Boost, which should be set to 1.53. I included Boost.Test, I think by #including boost/test/include/unit_test.hpp so everything comes in without linking in the library directly. There was some sort of error involving "putenv," not sure what anymore. I "fixed" it by switching to the trunk branch. Now I'm trying a new setup, with Eclipse. This time I'm adding Boost.Test by adding the files directly to the project list. (I'm experimenting with splitting my tests into 3 files.) I'm referencing the release branch again, which should still be on 1.53. I got "'putenv' was not declared in scope" error. It's at Line 95 of boost/test/utils/runtime/config.hpp. Did a hard error sneak by everyone, or is my setup incomplete? Both IDE setups use G++ on MinGW for the compiler. Is there some #define I'm missing? Should I switch to using the trunk again? Daryle W.

1 0

All talks for Meeting C++ 2013 are online!
by Jens Weller 06 Jun '13

06 Jun '13

Hi boost & C++ Community, to keep this short, all talks are online now, the schedule comes next week: http://meetingcpp.com/index.php/talks.html kind regards, Jens Weller

1 0

merge of bugfixes still possible
by Oliver Kowalke 06 Jun '13

06 Jun '13

Hi, I got a bug-report two days before - I'd like to merge the bugfix into the release. Do I get the permission? Oliver

2 1

[GIL] Can image::recreate reuse the memory?
by TONGARI 06 Jun '13

06 Jun '13

Hi, I'd expect image::recreate to reuse the memory much like std::vector::resize, but looked into the code shows that it creates a new one and swaps... So, is there a way to 'resize' the image without reallocating if the internal memory is sufficient? Thanks

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server and client chat via boost::asio
by Nguyễn Trường Lâm 06 Jun '13

06 Jun '13

Hello everyone. I want to write a program using socket, a client and a server to communicate between each other. But i dont know how write a message to server and display in a IDE terminal. Thank you for your help

2 1

Migrating svn.boost.org
by DongInn Kim 06 Jun '13

06 Jun '13

Hi, This time I would like to setup a schedule to migrate svn.boost.org to the new server (wowbagger.crest.iu.edu) This migration may need some downtime on the subversion, trac, and svnmanager services because we do not want to have any inconsistencies in SVN and or trac database. I have already rsynched the 1) boost SVN repository including its hook script, 2) trac db, and 3) SVNManager and its database. Do you have any hidden processes to manage the subversion repository, trac, or SVNManager? I implemented some simple testings with some SVN activities on the new server and it seems to work fine. Can anyone volunteer to play with the migrated SVN repository, trac, and SVNManager on the new server? I can test the very basic stuff and I may miss some functionalities of the current services. If anyone who actually work on the boost project can check this out, it would be much appreciated. I would feel much safer. 1. The downtime that we may have while migrating svn.boost.org I expect that TTL value be changed to 1hour or so. While the new DNS entries are populated, the current server will NOT service svn.boost.org and the new server will instead. - Date: Wednesday June 5th, 2013 - Time: 11:00am-12:00pm Pacific US time 12:00pm-1:00pm Mountain US time 1:00pm-2:00pm Central US time 2:00pm-3:00pm Eastern US time 6:00pm-7:00pm GMT 2. The unavailable services hosted on svn.boost.org : - Subversion - trac - SVNManager 3. The DNS entries to update: - Make svn.boost.org and wiki.boost.org point to 129.79.13.33 Please let me know if you have any questions or concerns about this migration. Regards, -- - DongInn

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Re: [boost] [circular_buffer] New version of documentation
by Paul A. Bristow 06 Jun '13

06 Jun '13

> -----Original Message----- > From: Boost [mailto:boost-bounces@lists.boost.org] On Behalf Of Marshall Clow > Sent: Thursday, May 23, 2013 8:01 PM > To: boost(a)lists.boost.org > Subject: Re: [boost] [circular_buffer] Volunteer(s) needed After more work than I bargained for (see below for excuses) I have produced a Quickbook, Doxygen, Autoindex version from the existing documentation for Boost.Circular_Buffer at https://svn.boost.org/svn/boost/trunk/libs/circular_buffer/doc/circular_buf… I have made few substantive changes to the text, mainly adding more hyperlinks, (and correcting some that were wrong of missing - using the inspect tool is a really, really good idea!) So that users can comment on this new version, I have put html and pdf versions in my Dropbox. The pdf version is at https://dl.dropboxusercontent.com/u/43940943/circular_buffer.pdf which can of course be viewed by any PDF reader (I have recently moved to using Foxit instead of Adobe Reader). The html Quickbook version is from folder (libs/circular_buffer/doc/html) the at https://dl.dropboxusercontent.com/u/43940943/html/index.html (Sadly some of the icon .png files are inaccessible from the Dropbox version, which mars its beauty but you'll get the idea). This library uses the full automatic indexing of C++ names and hyperlinking to and from the text. The header files have the classes and functions fully documented in Doxygen format, and this is used to create the C++ reference sections: https://dl.dropboxusercontent.com/u/43940943/html/boost_circular_buffer_c__… to that you can see what the classes do and the parameters, template parameters, returns etc for the functions. I believe that these details are essential for Really Useful documentation. The original Doxygen standalone (whose format some users prefer) is at https://dl.dropboxusercontent.com/u/43940943/doxygen/html/index.html So you can see the pros and cons of the same information displayed side by side. The PDF and HTML versions also has an index at the end (this could be improved as it only gives C++ functions etc at present). Enjoy! (?) Comments welcome - praise preferred ;-) Paul PS Implementation notes: To get all the links correct proved *very* tiresome. Much of the trouble was inconsistent layout of existing documentation and files. IMO we need to use the GITMOD project to impose much more order on the file structure. I fear that the modularization changes will invalidate many links in documentation, so much revision will be needed :-( We must be able to predict where index.html etc will be to be able to write links without the current hassle. The Boost inspect tool proved invaluable, and all links are now reported correct. (Lots were wrong - in Doxygen comments in the header files, and in the Quickbook stuff :-( ) Despite this, there are still some sections in red where the html layout is wrong :-( I hope to find all of these in a later revision. --- Paul A. Bristow, Prizet Farmhouse, Kendal LA8 8AB UK +44 1539 561830 07714330204 pbristow(a)hetp.u-net.com

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Ticket spam
by Hartmut Kaiser 06 Jun '13

06 Jun '13

This ticket got some (harmless) spam added: https://svn.boost.org/trac/boost/ticket/6126#comment:21. What can I do to remove that comment? Regards Hartmut --------------- http://boost-spirit.com http://stellar.cct.lsu.edu

2 1

[community] request for revision: generic programming
by Steve Lorimer 06 Jun '13

06 Jun '13

In the light of C++11, the page on generic programming techniques http://www.boost.org/community/generic_programming.html is somewhat outdated. Any chance of a revision?

2 1