February 2013 - Boost - lists.preview.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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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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[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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[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]

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[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

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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.

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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

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

[TypeErasure] references
by Chapman, Alec 10 May '13

10 May '13

Hi Steven, I have a somewhat-generic type erasure class that I would like to switch to yours. The main difficulty I can see is in the way capturing by reference is handled. The approach I take in my class is to pass a boost::reference_wrapper to the constructor: typedef mpl::vector<copy_constructible<>, type_id_<>, incrementable<> > requirements; int i = 0; any<requirements> x(boost::ref(i)); // capture i by reference ++x; // i == 1 any<requirements> y(x); // makes a copy of i ++y; // i == 1, any_cast<int>(y) == 2 My motivation is that I have a bunch of template functions already written that I often call directly, but in other cases I need to compile them separately by instantiating them with any<...>: ---------------------- module 1 ------------------------- // some long algorithm that I don't want to modify to be aware of any<...> template<class T> void f(T& t) { ++t; T t2 = t; ++t2; // do something with t2 } // make a type-erased version for separate compilation void any_f(any<requirements>& x) { return f(x); } -------------------- module 2 ---------------------------- // provide a thin wrapper that applies type erasure before calling any_f template<class T> void f_fwd(T& t) { any<requirements> x(boost::ref(t)); any_f(x); } // some function that needs to call f void g(int& i) { // do something with i... // then pass it to f f_fwd(i); } Is something like this possible with your method? Are there advantages that I'm not seeing to having the type signature contain information about whether the object is held by reference? Thanks, Alec

3 6

[GSOC] Are we going to participate?
by Antony Polukhin 02 May '13

02 May '13

Hi all, Today starts Google Summer of Code. Is Boost community will become one of the mentoring organizations? What project ideas are we proposing? (As for me, I'd love to see unique_ptr+unique_array implemented using Boost.Move; C++11 features support for MPL, Fusion, Graph, Bind, Optional; BTree library; library for getting system info) -- Best regards, Antony Polukhin

16 24

What Should we do About Boost.Test?
by Dave Abrahams 16 Apr '13

16 Apr '13

Hi All, I was just going through Boost.Test to try to figure out how to teach it, and while it looks to have substantial value, it is also in quite a mess. It contains loads of features that are exercised in the examples/ directory but neither included in any of the tests nor documented. There are facilities for command-line argument parsing! There are "decorators" that turn on/off features for test cases. There is support for mock objects! These are cool and sometimes necessary features, but who knew? The third tutorial page (http://www.boost.org/doc/libs/1_51_0/libs/test/doc/html/tutorials/new-year-…) has a glaring typo in the code examples: "BOOST_AUTO_EST_CASE". There's no reference manual at all. There are nearly-identical files in the examples/ directory called "est_example1.cpp" and "test_example1.cpp" (Did the "t" key on someone's keyboard break?) I could go on, but where would I stop? I don't know what to do about this. Because of the lack of redundancy (i.e. tests and documentation), it's hard to tell whether this library is correct or even to define what "correct" should mean. It seems like, as long as the code is incompletely / incorrectly documented and tested, it's just someone's personal coding project that we happen to keep shipping with Boost, and not really a library for general use. This situation reflects poorly on Boost as a whole and the fact that it centers around a _testing_ library, which is concerned with robustness... well, let's just say that the irony isn't lost on me. I don't mean this posting as an attack on Gennadiy in any way, but I think the situation is unacceptable and therefore am opening a discussion about what should happen. As a straw man, I'll make this suggestion: - Boost.Test is officially deprecated in the next release - Its documentation, such as it is, is removed from the release after that - Meanwhile, other tests in Boost that use this library are rewritten to use a different mechanism - The code is removed from Boost thereafter I am not at all attached to removing Boost.Test from Boost, but IMO rescuing it would require a significant new investment of time and energy from people who are committed to bringing the library up to par with the rest of what we do. (I seriously thought about volunteering for this myself, but realistically speaking, I don't have the time, and volunteering for something you can't actually do is worse than not volunteering at all.) Even if volunteers show up, I'd suggest proceeding with the plan above, subject to reversal at any time the work actually gets done. Thoughts? -- Dave Abrahams BoostPro Computing Software Development Training http://www.boostpro.com Clang/LLVM/EDG Compilers C++ Boost

34 85

future<>::then() Error returning future<void> (on trunk)
by Fernando Pelliccioni 07 Apr '13

07 Apr '13

Hi Vicente, hi all, I noticed that in the trunk there is a implementation of future<>::then(). Thank you very much for your efforts to implement it! The following example, compiles OK boost::future<int> f1 = boost::async([]() { return 123; }); f1.then([](boost::future<int> const& f) { return std::string(""); }); But this one fails to compile: boost::future<int> f1 = boost::async([]() { return 123; }); f1.then([](boost::future<int> const& f) { }); Here future<>::then() have to returns future<void> like ... boost::async([]() { }); Am I right? On the other hand, have you taken into account the following paper? http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3451.pdf Regards, Fernando Pelliccioni.

3 5

Review managers wanted for augmented data structures
by Vadim Stadnik 06 Apr '13

06 Apr '13

Hi all, At present, neither Boost library nor STL provides containers using augmented data structures. I suggest that the Boost community consider solving the challenging problem – how to extend STL by integrating advanced data structures. Is there an alternative of not integrating advanced data structures into STL? IMO, no, since it is equivalent to “STL must go”. C++ cannot ignore performance benefits provided by these data structures. On the other hand, advanced data structures can be implemented in many programming languages and this will make C++ less competitive. Augmented red-black trees could have been included in the very first version of STL. Why is it difficult and has not been done yet? The major obstacle for the integration is the C++ standard specification of computational complexities of single operations for containers and iterators. Augmented trees are non-standard due to different performance guarantees. At the same these data structures are beneficial for complex algorithms, since they offer a wider set of more efficient operations compared to standard containers. The typical performance improvement for one operation is O(log N) against O(N). For less efficient operations these trees normally provide running time O(log N) against O(1), which is good enough for many applications. The C++ STL will be under pressure as long as there are new data structures that offer better running time for user algorithms. Asymptotically, the main parameter that determines the running time of an algorithm is the total computational cost (to simplify the discussion we omit the effect of locality of reference). By definition, the total computational cost is the sum of costs of single operations multiplied by their frequencies. For a general purpose library, such as STL, it is impossible at the design stage to know frequencies of all container and iterator operations required in all possible user algorithms. A more reasonable and practical approach to STL would be to provide a wide set of interchangeable containers and data structures with different performance guarantees and allow programmers to make decisions about the most suitable containers for specific applications. Relatively small frequencies of inefficient operations do not have significant effect on the total computational cost of an algorithm. Thus, in principle, containers and iterators can provide even inefficient operation in order to support more unified interfaces and to improve the generality. The replacement of interchangeable containers offers the advantage of low development cost solutions to performance bottlenecks that arise due to enhancement requests and/or an increase in the number of elements processed by a user algorithm. Also, I’d like to note that the representation of sequences using augmented trees is a frequent point of confusion and probably the fact that was overlooked in the development of previous versions of STL. The general description of the method of augmenting data structures is given in the section 14.2 of this book T.H. Cormen, C.E. Leiserson, R.L. Rivest and C. Stein, Introduction to Algorithms, 2nd Edition, MIT Press and McGraw-Hill, 2001. The specific application of this method is provided for order statistic trees and interval trees. Unfortunately, there is no example of a sequence that stores unordered elements. Probably for this reason augmented red-black trees are often considered to be an improvement of search trees only. The efficient representation of sequences by the described red-black trees follows from the fact that augmenting by the counter of children nodes supports efficient mapping from non-negative integers into container elements. It works both for ordered and unordered containers with unique and multiple elements or keys. There are two libraries in the Boost review schedule: http://www.boost.org/community/review_schedule.html "STL Extensions" and "Countertree". None of them has as yet a review manager. The order of the reviews may not be significant. It is more important that at least one library pass the review. This would help integrating other advanced data structures. Are there Boost experts who could volunteer to take responsibility of review manager for any of these two libraries? Regards, Vadim Stadnik

2 4

[fusion] What do we do with nil ?
by Joel de Guzman 31 Mar '13

31 Mar '13

Hello, This is a constantly nagging issue. There are a couple of places where nil is a PP define especially on the Mac: - objc.h #ifndef nil #define nil __DARWIN_NULL #endif and - MacTypes.h #ifndef nil #define nil NULL #endif So people complain because fusion uses nil as: namespace boost { namespace fusion { struct nil; }} So, nil is a reserved word in Objective-C. But this is C++! And that define is SUCH A BAD PRACTICE in C++! Some folks, like Paul Mensonides maintains a strong stance against this: I would just use #define nil nil as a sanity check and call it done. If the symbol is already defined, compilation error (or at least warning on overly permissive compilers). The symbol will be need to be undefined in between the inclusion of the two libraries. Workarounds like nil_ and (min)(...) just perpetuate the problem. Fix the root problem rather than treating the symptom indefinitely. Otherwise, where is the line drawn? Even if you can't provide a transparent fix (such as defining nil as a constant and min/max as functions), the backwards compatibility argument fails in the long run. The amount of effort required to make the necessary changes to existing code will eventually be outweighed by the effort to implement workarounds put into new code (as well as educate everyone that they are necessary)--especially in cases like these which can mostly be emulated in a way that causes most existing code to work. As I said over and over again, I'm listening and I would want to "fix" this issue if someone comes up with a reasonable (tested) patch that: 1) Detects the platform 2) Renames fusion::nil to something else (only for the affected platform) Yet, no-one wants to do this. Instead we get nasty remarks such as those found here: https://svn.boost.org/trac/boost/ticket/5010#comment:16 What do we do? I'm seeking for a resolution. Regards, -- Joel de Guzman http://www.boostpro.com http://boost-spirit.com

4 5

[exception] uncaught_exception_count, scope(failure), scope(success)
by Evgeny Panasyuk 31 Mar '13

31 Mar '13

Hello All, There is implementation of uncaught_exception_count - https://github.com/panaseleus/stack_unwinding/blob/master/boost/exception/u… . 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. uncaught_exception_count allow us to implement scope(failure) and scope(success) features from D language in C++. ( previous discussion is at http://boost.2283326.n4.nabble.com/scope-exit-D-style-scope-failure-and-sco… ) Implementation of uncaught_exception_count is tested on {Clang 3.2, GCC 3.4.6, GCC 4.1.2, GCC 4.4.6, GCC 4.4.7, MSVC2005SP1, MSVC2008SP1, MSVC2010SP1, MSVC2012} x {x32, x64}. There are also live stress tests - detection of 500 simultaneous uncaught exceptions: GCC 4.6.3: http://liveworkspace.org/code/2qmSso%240 GCC 4.7.2: http://liveworkspace.org/code/dY0VD%240 Clang 3.2: http://liveworkspace.org/code/49MaPk%240 I think that uncaught_exception_count (and uncaught_exception_count_latch primitive) can be added into Boost.Exception library, at least into "detail" section. After that scope(failure) and scope(success) features can be implemented in Boost.ScopeExit library. Note, approximately 14 of 16 Boost.ScopeExit examples in manual are in fact emulations of scope(failure)/scope(success). So, looks like in first place Boost.ScopeExit was introduced to simplify emulation of scope(failure) and scope(success) features. What do you think? Thank you. Best Regards, Evgeny Panasyuk

5 11

GSOC 2013
by David Bellot 22 Mar '13

22 Mar '13

Only 2 projects have been proposed so far for GSOC 2013: wake up Boost ! https://svn.boost.org/trac/boost/wiki/SoC2013 :-D

7 7

[config] consexpr workaround
by vicente.botet 21 Mar '13

21 Mar '13

Hi, in order to make easier the introduction of constexpr in a portable way I would like we add a Boost Config workarround. We can define some macros depending on whether BOOST_NO_CONSTEXPR is defined or not. #if defined(BOOST_NO_CONSTEXPR) #define BOOST_CONSTEXPR #define BOOST_CONSTEXPR_OR_CONST const #else #define BOOST_CONSTEXPR constexpr #define BOOST_CONSTEXPR_OR_CONST constexpr #endif For most of the constexpr functions or constructors BOOST_CONSTEXPR will work. constexpr tuple(); =versus= BOOST_CONSTEXPR tuple(); When used for static constants BOOST_CONSTEXPR_OR_CONST is needed as we need to preserv the const keyword when consexpr is not available. static constexpr UIntType xor_mask = a; =versus= static BOOST_CONSTEXPR_OR_CONST UIntType xor_mask = a; We could also add a STATIC_CONSTEXPR macro #define BOOST_STATIC_CONSTEXPR static BOOST_CONSTEXPR_OR_CONST static constexpr UIntType xor_mask = a; =versus= BOOST_STATIC_CONSTEXPR UIntType xor_mask = a; For this case the existing macro BOOST_STATIC_CONSTANT could be modified to use BOOST_CONSTEXPR_OR_CONST when static const was used. static constexpr UIntType xor_mask = a; =versus= BOOST_STATIC_CONSTANT(UIntType, xor_mask = a); Can we introduce this workaround? Best regards, Vicente _____________________ Vicente Juan Botet Escribá http://viboes.blogspot.com/

6 17

[math] Support for libquadmath/ __float128
by Claas 19 Mar '13

19 Mar '13

I have experimented with the quadmath library included with gcc and the boost::math::constants library and encountered several problems. - typeid is seemingly not supported for __float128, which requires an overload of nameof<__float128> - the stream extraction operator has to be provided for __float128 for string conversion to work - a specialisation of numeric_limits has to be provided. Is there an interest in incorporating __float128 into boost ? If so, would it be a good idea to specialise constants for __float128 as well, apart from float, double and long double? Regards Claas

6 19

[gil] What is the status of the Gil extension numeric?
by Krzysztof Czainski 18 Mar '13

18 Mar '13

Hello, During my first steps wit Boost.Gil I bumped onto an example [1], that uses the numeric extension. For this extension, the the example [1] and a ling from Boost.Gil docs [4] point to [2], where I couldn't find any Gil extensions to download. Most Google links pointed to the same page, but I finally found [3]. So my questions are: a) Is there a plan to add the extension numeric to Boost? b) Is [3] the newest version? And could the Boost.Gil docs be updated to point to the right place? c) I corrected a few bugs in boost/gil/extension/numeric/sampler.hpp -- is this list the right place to discuss modifications to the numeric extension? Regards, Kris [1] http://www.boost.org/doc/libs/1_53_0/libs/gil/example/resize.cpp [2] http://opensource.adobe.com/gil [3] http://code.google.com/p/gil-contributions/ [4] http://www.boost.org/doc/libs/1_53_0/libs/gil/doc/index.html

1 0

Help in setupping regression tests on ARM
by Antony Polukhin 16 Mar '13

16 Mar '13

I've successfully run nests on x86, but on ARM I've got the following message: # Running Boost.Build tests Traceback (most recent call last): File "run.py", line 60, in <module> runner(root) File "/home/pi/boost_maintain/run_trunk/tools_regression_src/regression.py", line 205, in __init__ self.main() File "/home/pi/boost_maintain/run_trunk/tools_regression_src/regression.py", line 566, in main getattr(self,action_m)() File "/home/pi/boost_maintain/run_trunk/tools_regression_src/regression.py", line 531, in command_regression self.command_test() File "/home/pi/boost_maintain/run_trunk/tools_regression_src/regression.py", line 329, in command_test self.command_test_boost_build() File "/home/pi/boost_maintain/run_trunk/tools_regression_src/regression.py", line 369, in command_test_boost_build "boost/bin.v2/libs/any/test/any_test.test")); OSError: [Errno 2] No such file or directory: '/home/pi/boost_maintain/run_trunk/results/boost/bin.v2/libs/any/test/any_test.test' I try to run tests on RaspberryPi, it is armhf. Compilller is GCC-4.6.3, 25Gb of free space on SD card. It looks strange, that I see only a few folders in /home/pi/boost_maintain/run_trunk/results/boost/bin.v2/libs/ (there are only 6 folders) -- Best regards, Antony Polukhin

2 7

[type_traits] Some traits are missing
by Antony Polukhin 15 Mar '13

15 Mar '13

Hi all, Equivalents of following traits are in C++11 Standard, but missing in Boost.TypeTraits library: has_nothrow_move_assign has_nothrow_move_constructor has_trivial_move_assign has_trivial_move_constructor Extremely naive implementation of those functions exist in Boost.Variant, so as a start we can use them. Or am I missing something and there is a reason, why those traits are not included in Boost.TypeTraits? -- Best regards, Antony Polukhin

3 6

[thread] thread_specific_ptr leaks on VS2012 when using std::async()
by Klaim - Joël Lamotte 05 Mar '13

05 Mar '13

Hi, The title says it all. I think I found a memory leak with the help of boost.log author Andrei Semashev. I was using Boost.Log in Visual Studio 2012 (released one) and tried to use Visual Leak Detector because Visual Studio basic leak detector was reporting leaks. I isolated the leaks to usage of log and switched to VLD to check if the basic detector wasn't giving me false positive. I contacted Andrei to see if he could check it but he don't have VS2012 available so I setup some tests to isolate the problem. In the end of our exchange we concluded it was a false positive (it only leak on end of program). However it is still an annoying noise in the leak report logs, so people not understanding the source of this problem might be interested in this email. I attach the whole email exchange to this email, tell me if leak logs are necessary too. The last version of my test is at the end of the email (first program). Basically, the leak appear only when using std::async() in combination of boost::thread_specific_ptr : - using exclusively boost threading libraries (both with dynamic and static linking) result in no leak - using exclusively std threading libraries but not std::async() result in no leak - using std::async() result in a leak The second test program shows that using Intel Threading Building Blocks, I get leaks only if : - I use std::async() in combination with boost::thread_specific_ptr, as before (I mean I use tbb without a leak, then I add a std::async() call to the same task function and there is a leak) - I don't use std::async() but I don't manage the lifetime of tbb task scheduler We think the threads spawned by both tbb (that is supposed to be a superset of ppl) and std::async() (that is supposed to use ppl/concrt task scheduler) are not ended yet when the program reach the end of main (which seems logical as the task scheduler is then managed as a static global), making boost::thread_specific_ptr not release some data on thread destruction, as it is notified too late and any leak detection tool willl generate noise due to this. A way to fix this is to explicitely end the task scheduler, being tbb or ppl/concrt. I will use tbb task scheduler explicitely initialized/terminated in my project so it will solve the problem on my side. Joel Lamotte ------------------------------------ // this program was used to see the memory leak #define TEST_ASYNC // comment this to make it linear and not leak //#define WITH_BOOST_THREADS #define WITH_STD_ASYNC // uncomment this to leak //#define WITH_BOOST_LOG // boost log also leak if std::async is used #include <boost/thread.hpp> #ifdef WITH_BOOST_THREADS # include <boost/thread/future.hpp> # include <boost/chrono.hpp> # define THIS_THREAD boost::this_thread # define THREAD_LIB boost::thread # define CHRONO_LIB boost::chrono # define MY_FUTURE boost::future #else # include <future> # include <thread> # include <chrono> # define THIS_THREAD std::this_thread # define THREAD_LIB std::thread # define CHRONO_LIB std::chrono # define MY_FUTURE std::future #endif #ifdef WITH_BOOST_LOG # include <boost/log/trivial.hpp> # define MY_LOG BOOST_LOG_TRIVIAL(info) #else # include <iostream> # define MY_LOG std::cout << '\n' #endif #define BASIC_VS_LEAK_DETECTOR 0 #define VISUAL_LEAK_DETECTOR 1 #define LEAK_DETECTOR VISUAL_LEAK_DETECTOR #if LEAK_DETECTOR == BASIC_VS_LEAK_DETECTOR # define _CRTDBG_MAP_ALLOC # include <stdlib.h> # include <crtdbg.h> #else # include "vld.h" #endif struct my_data { char data[1024]; my_data() { MY_LOG << "CONSTRUCTOR my_data - " << THIS_THREAD::get_id(); } ~my_data() { MY_LOG << "DESTRUCTOR my_data - " << THIS_THREAD::get_id(); } }; boost::thread_specific_ptr< my_data > ts_ptr; void my_thread_foo() { ts_ptr.reset(new my_data()); } int work() { for( int i = 0; i < 42; ++i ) { MY_LOG << "THIS IS A MESSAGE - I = " << i; MY_LOG << "ts_ptr = " << ts_ptr.get(); my_thread_foo(); THIS_THREAD::sleep_for( CHRONO_LIB::milliseconds(10) ); } return 0; } int main(int argc, char *argv[]) { #if LEAK_DETECTOR == BASIC_VS_LEAK_DETECTOR // First simple memory leak detection for Visual Studio // use _crtBreakAlloc to put a breakpoint on the provided memory leak id allocation //_crtBreakAlloc = 1149; _CrtSetDbgFlag ( _CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF ); #endif //int* k = new int[42]; // to check that memory leak detection does work MY_LOG << "Hello, World!"; #ifdef TEST_ASYNC # ifndef WITH_BOOST_THREADS std::vector< std::future<int> > work_in_progress(2); # ifdef WITH_STD_ASYNC for( auto& ftr : work_in_progress ) { ftr = std::async( work ); } # else for( auto& ftr : work_in_progress ) { std::packaged_task< int() > task(work); ftr = task.get_future(); std::thread thread( std::move(task) ); thread.detach(); } # endif for( auto& ftr : work_in_progress ) { ftr.get(); } # else std::vector< boost::unique_future<int> > work_in_progress(42); for( auto& ftr : work_in_progress ) { boost::packaged_task<int> task(work); // boost's packaged_task don't take the full signature as parameter, it takes the return type only ftr = task.get_future(); boost::thread thread( boost::move(task) ); thread.detach(); } for( auto& ftr : work_in_progress ) { ftr.get(); } # endif #else for( int i = 0; i < 42; ++i ) { work(); } #endif MY_LOG << "END"; return EXIT_SUCCESS; } -------------------------------------- // this program tests if the memory leaks appear with Threading Building Blocks #define BASIC_VS_LEAK_DETECTOR 0 #define VISUAL_LEAK_DETECTOR 1 #define LEAK_DETECTOR VISUAL_LEAK_DETECTOR #define WITH_ROOT_TASK //#define WITH_BOOST_LOG //#define WITH_STD_ASYNC // uncomment to leak #ifdef WITH_STD_ASYNC # include <future> #endif #include <thread> #include <atomic> #include <boost/thread.hpp> #include <tbb/tbb.h> #include <tbb/task_scheduler_init.h> #ifdef WITH_BOOST_LOG # include <boost/log/trivial.hpp> # define MY_LOG BOOST_LOG_TRIVIAL(info) #else # include <iostream> # define MY_LOG std::cout << '\n' #endif #if LEAK_DETECTOR == BASIC_VS_LEAK_DETECTOR # define _CRTDBG_MAP_ALLOC # include <stdlib.h> # include <crtdbg.h> #else # include "vld.h" #endif namespace test { struct my_data { char data[1024]; }; boost::thread_specific_ptr< my_data > ts_ptr; void my_thread_foo() { ts_ptr.reset(new my_data()); } class UpdateTask : public tbb::task { public: UpdateTask() : idx( s_idx++ ) { MY_LOG << "[UpdateTask " << idx << " ] " << std::endl; } ~UpdateTask() { MY_LOG << "[/UpdateTask " << idx << " ]" << std::endl; } tbb::task* execute() { MY_LOG << "[" << std::this_thread::get_id() << "] Tick "<< m_count <<std::endl; my_thread_foo(); ++m_count; if( m_count < 100 ) { // make sure this is re-executed this->increment_ref_count(); this->recycle_as_safe_continuation(); } return nullptr; } private: static std::atomic<int> s_idx; std::atomic<int> m_count; const int idx; }; std::atomic<int> UpdateTask::s_idx = 0; class TaskScheduler // using TBB { public: #ifdef WITH_ROOT_TASK TaskScheduler() : m_root_task( *new (tbb::task::allocate_root()) tbb::empty_task ) { m_root_task.increment_ref_count(); } ~TaskScheduler() { m_root_task.destroy(m_root_task); } #endif void register_update_task() { #ifdef WITH_ROOT_TASK m_root_task.increment_ref_count(); UpdateTask& updater = *new(m_root_task.allocate_child()) UpdateTask(); #else UpdateTask& updater = *new(tbb::task::allocate_root()) UpdateTask(); #endif m_task_list.push_back( updater ); } void run_and_wait() { #ifdef WITH_ROOT_TASK m_root_task.spawn( m_task_list ); m_root_task.wait_for_all(); #else tbb::task::spawn_root_and_wait( m_task_list ); #endif } private: tbb::task_list m_task_list; // uncomment the following line to not leak tbb //tbb::task_scheduler_init m_engine_instance; // We explicitly create and destroy the TBB task scheduler to avoid memory leak warning noises. #ifdef WITH_ROOT_TASK tbb::task& m_root_task; #endif }; void tbb_test() { TaskScheduler task_scheduler; for( int i = 0; i < 50; ++i ) { task_scheduler.register_update_task(); } task_scheduler.run_and_wait(); } } int main(int argc, char *argv[]) { #if LEAK_DETECTOR == BASIC_VS_LEAK_DETECTOR // First simple memory leak detection for Visual Studio // use _crtBreakAlloc to put a breakpoint on the provided memory leak id allocation //_crtBreakAlloc = 148; _CrtSetDbgFlag ( _CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF ); #endif #ifdef WITH_STD_ASYNC std::atomic<bool> finished = false; std::async( [&]{ while( !finished ) { MY_LOG << "POP"; test::my_thread_foo(); std::this_thread::sleep_for( std::chrono::milliseconds(500) ); } } ); #endif test::tbb_test(); #ifdef WITH_STD_ASYNC finished = true; #endif MY_LOG << "\nEND"; std::this_thread::sleep_for( std::chrono::seconds(4) ); return 0; }

3 5

[thread] C++11 once_flag enabled when constexpr is not available
by Andrey Semashev 05 Mar '13

05 Mar '13

Hi, Vicente! I see you applied my patch for call_once but you seem to forgot to disable the C++11 call_once interface when the compiler does not support constexpr. Was that intentional or you just missed it? Anyway, please find the patch attached.

3 3

[thread] boost::thread and thread safety annotations
by Wladimir 04 Mar '13

04 Mar '13

Hello, The Clang C++ compiler project is currently working on a thread safety analyzer. By making use of so-called thread safety annotations within the source code, several problems with synchronization primitives can be found statically. For example: usage of a data structure without acquiring its guarding lock. See here for an overview of the available attributes: http://clang.llvm.org/docs/LanguageExtensions.html#threadsafety It is customary to use these attributes by defining macros, for compatibility: http://www.mail-archive.com/linuxkernelnewbies@googlegroups.com/msg01455.ht… At one time, it was also supposed to end up in G++, but this was abandoned in favor of clang (see http://gcc.gnu.org/wiki/ThreadSafetyAnnotation) But at least the annotations are fairly standardized. I think it would be useful to add these annotations to boost::thread, so that projects using that library can make use of the static checking. As I understand it, is only a matter of marking data structures that serve as lock/scoped_lock (such as boost::mutex, boost::recursive_mutex, ...), and methods that act upon the lock with the appropriate attributes. Any interest in this? Regards, Wladimir

2 1

[thread] barrier::wait() not marked as interruption_point
by Oliver Kowalke 04 Mar '13

04 Mar '13

In the documentation (1.53 beta) barrier::wait() is not marked as interruption-point nor that it will throw thread_interrupted if thread blocked inside barrier::wait() if it gets interrupted. Because barrier::wait() calls condition_variable::wait() and condition_variable::wait() is a interruption-point barrier::wait() should it be too - or do I miss something? Oliver

2 1

[persistent] Library preview: Persistent
by Stefan Strasser 04 Mar '13

04 Mar '13

Hi everyone, I'm thinking about finishing a library that was proposed a couple of years ago. It was pretty far along, and there is documentation available in the sandbox (somewhat outdated): https://svn.boost.org/svn/boost/sandbox/persistent/libs/persistent/doc/html… It is a library with the goal of storing C++ objects on disk, with an interface that is as close as possible to accessing regular C++ objects in memory. A very simple example could look like this: shared_loc<person> p=...; { transaction tx; p->name="..."; p->address="..."; tx.commit(); } It is based on Boost.Serialization, but automatically maintains a consistent state on disk (ACID transactions), which can be updated incrementally. Part of its code was moved to a library named Transact to work alongside other transactional resources (like memory) and is available in the sandbox: https://svn.boost.org/svn/boost/sandbox/transaction/boost/transact/ I'd like to know whether the boost community is still interested in such a library, and I suppose there are quite a few new people here so your comments are welcome as well. Thank You!

6 9

[type traits] is_literal_type ?
by Robert Ramey 02 Mar '13

02 Mar '13

Any chance of a boost implementation for is_literal_type? Robert Ramey

4 6

Git Conversion Schedule
by Sebastian Redl 02 Mar '13

02 Mar '13

Hi, According to the timeline linked from the svn.boost.org frontpage, we're already using Git: https://svn.boost.org/trac/boost/wiki/ModCvtSchedule But I'm pretty sure that's not the case, right? What is the current schedule? Sebastian

3 2

[tweener] How to copy image files in documentation
by Julien Jorge 01 Mar '13

01 Mar '13

Hi, I wrote the documentation of Boost.Tweener in boostbook format. I have references to some images in the documentation but they are not copied in the target html directory when I type bjam html How can I make the image directory to be automatically copied in the target directory of the generated documentation? Since I am not familiar with the build process of Boost yet, I would accept a reason not to do this as an answer :) Regards, Julien Jorge

2 2

[type_erasure] overloading macro
by Christophe Henry 28 Feb '13

28 Feb '13

Hi all, I played a bit more with overloading and it started being annoying and error-prone to add more overloads of concept_map (with more arguments) so I wrote a small macro to 1) generate my overloads and 2) save myself the time reading compiler errors when I use BOOST_TYPE_ERASURE_MEMBER and make a mistake in the number of arguments. It's for C++11 (argument pack) as it's all I need at the moment but I suppose that with Boost.Preprocessor, it'd be for C++03 doable. Well, in case it'd be of any use to someone, here it is, with a small test (tested with g+ 4.5 with -std=c++0x). #include <boost/type_erasure/concept_interface.hpp> #include <boost/type_erasure/rebind_any.hpp> #include <boost/type_erasure/derived.hpp> #include <boost/type_erasure/is_placeholder.hpp> #include <boost/type_erasure/constructible.hpp> #include <boost/type_erasure/relaxed_match.hpp> #include <boost/type_erasure/any.hpp> #include <boost/type_erasure/builtin.hpp> #include <boost/type_erasure/any_cast.hpp> #include <boost/type_erasure/detail/macro.hpp> #include <boost/mpl/vector.hpp> #include <iostream> #ifndef BOOST_NO_CXX11_VARIADIC_TEMPLATES #define BOOST_TYPE_ERASURE_MEMBER_VARIADIC_I(qualname,concept_name,member) \ BOOST_TYPE_ERASURE_OPEN_NAMESPACE(qualname) \ template <typename T, typename... Args> \ struct concept_name{ \ static void apply(const T& t, const Args... a) { t.member(a...); } }; \ BOOST_TYPE_ERASURE_CLOSE_NAMESPACE(qualname) \ namespace boost { namespace type_erasure { \ template<class T, typename... U, class Base, class Enable> \ struct concept_interface< BOOST_TYPE_ERASURE_QUALIFIED_NAME(qualname)<T, U... >, Base, T, Enable> : Base { \ typedef void _fun_defined; \ void member(typename rebind_any<Base, U>::type... arg)const \ {call(BOOST_TYPE_ERASURE_QUALIFIED_NAME(qualname)<T, U...>(), *this, arg...);} }; \ template<class T, typename... U, class Base> \ struct concept_interface< BOOST_TYPE_ERASURE_QUALIFIED_NAME(qualname)<T, U...>, Base, T, typename Base::_fun_defined> : Base{ \ using Base::member; void member(typename rebind_any<Base, U >::type... arg)const \ {call(BOOST_TYPE_ERASURE_QUALIFIED_NAME(qualname)<T, U...>(), *this, arg...);} }; \ }} #endif #define BOOST_TYPE_ERASURE_MEMBER_VARIADIC(qualified_name,member) \ BOOST_TYPE_ERASURE_MEMBER_VARIADIC_I( \ qualified_name, \ BOOST_PP_SEQ_ELEM(BOOST_PP_DEC(BOOST_PP_SEQ_SIZE(qualified_name)), qualified_name), \ member) // supports overloading, does not require any number of arguments BOOST_TYPE_ERASURE_MEMBER_VARIADIC((n1)(n2)(foo),foo) namespace mpl = boost::mpl; using namespace boost::type_erasure; struct Test { void foo()const { std::cout << "foo() called" << std::endl; } void foo(int i)const { std::cout << "foo(int) called with: " << i << std::endl; } void foo(int i,char c)const { std::cout << "foo(int,char) called with: " << i << "," << c << std::endl; } void foo(double d)const { std::cout << "foo(double) called with: " << d << std::endl; } void foo(int i,double d)const { std::cout << "foo(int,double) called with: " << i << "," << d << std::endl; } void foo(int i,double d,char c)const { std::cout << "foo(int,double,char) called with: " << i << "," << d << "," << c << std::endl; } }; int main() { Test t; any< mpl::vector< n1::n2::foo<_self>, n1::n2::foo<_self, int>, n1::n2::foo<_self, double>, n1::n2::foo<_self, int, double>, n1::n2::foo<_self, int, char>, n1::n2::foo<_self, int, double, char>, copy_constructible<> > > x (t); x.foo(); // calls foo() x.foo(1); // calls foo(int) x.foo(1.0); // calls foo(double) x.foo(1,1.0); // calls foo(int, double) x.foo(1,'a'); // calls foo(int, char) x.foo(1,1.0,'a'); // calls foo(int, double,char) return 0; }

2 21

[ptr_container, crc, format] Open tickets - code patches available
by Joachim Faulhaber 28 Feb '13

28 Feb '13

Hi, there are open tickets: https://svn.boost.org/trac/boost/ticket/7430 (ptr_container: warning fixes) https://svn.boost.org/trac/boost/ticket/7433 (crc: runtime check issue) https://svn.boost.org/trac/boost/ticket/7435 (format: crash) that we have submitted 5 months ago. Along with the bug reports there are code patches for the reported issues, that have been tested and used in production code on different platforms. We would kindly ask the maintainers to look at these issues and to apply the patches to the library code, so they can be integrated in the next release. In case the maintainers do not have time to fix these issues within say the next 2 weeks, I (Joachim) would like to ask for permission to apply the patches. Fixing the issues would be very helpful for us, so we don't have to patch the code locally for every new version. Thanks a lot, Joachim & Franz -- Interval Container Library [Boost.Icl] http://www.joachim-faulhaber.de

3 6

Releasing gil::io
by Christian Henning 28 Feb '13

28 Feb '13

Hi all, I have taken a look at the requirements to release a new library. There is some points I like to discuss. Technically speaking gil::io is a replacement of the older gil io extension. So, it's not really a new library. But of course, I don't mind fulfilling all the requirements. Here are the requirements before merging: * root/libs/libraries.htm entry is OK, both in the alphabetic list and in the category lists. Should I add a gil::io entry? * root/libs/maintainers.txt entry is OK. Should I add a gil::io entry? * The library's root/libs/xxx directory contains an index.html file with either the main docs or a redirection to the main docs. Done * The primary docs pages meet Boost requirements and guidelines. Don't leave this until too late; it has turned up lots of issues in the past. I'm using boostbook and the default templates. * Trunk inspection report is clean. I would need some help here to hook up gil::io test with general boost testing. * Trunk regression tests are reasonably clean or marked up. TODO Thanks, Christian

2 3

Fwd: [Thread] Solution to conflict with MFC?
by Thorsten Ottosen 28 Feb '13

28 Feb '13

Hi Thread maintainers, Anthony speaks about a patch to make this work. Does anyone know where it is? And could it be applied? Thanks -Thorsten -------- Original Meddelelse -------- Subject: [Thread] Solution to conflict with MFC? Date: Tue, 26 Apr 2011 13:28:56 +0200 From: Christian Larsen <contact(a)dword.dk> Reply-To: boost-users(a)lists.boost.org To: boost-users(a)lists.boost.org Newsgroups: gmane.comp.lib.boost.user Hello, I know this has been asked before, but I could not find a good solution. I'm experiencing problems with an application using both MFC and Boost.Thread. Specifically the assertion ASSERT(AfxGetModuleState() != AfxGetAppModuleState()); in AfxCoreInitModule() fails. I link Boost.Thread statically into a DLL in my project. From previous posts to this list and elsewhere, e.g. http://lists.boost.org/boost-users/2009/04/46929.php, I see that the issue is caused by setting _pRawDllMain in tss_pe.cpp. Commenting this line does "solve" the problem, but I would rather not have to hack the Boost source code this way. It seems there is a patch somewhere for this problem (referred to in http://lists.boost.org/boost-users/2009/04/47015.php) but it appears it never made it into the source. Is there any chance of this issue being solved in a better way? Best regards, Christian Larsen

5 9

[Config] N3276 decltype support on VC++ 11
by Michel Morin 28 Feb '13

28 Feb '13

IIRC, Stephan said that VC++ 11 supports N3276 decltype. Shall we "undef" BOOST_NO_CXX11_DECLTYPE_N3276 for VC++ 11? This enables automatic use of decltype-based `boost::result_of`. Trivial patch attached. Regards, Michel

11 79

[multi_index] Move Semantics
by Mark Snelling 27 Feb '13

27 Feb '13

Hi, I've been a user of Boost.MultiIndex for a number of years and think it's a great library. Is there any firm plan to add move semantics? It's been noted under "Future Work" in the docs since Boost 1.32. Regards, Mark

6 10

Proposed interface change to boost::algorithm::copy_while
by Marshall Clow 26 Feb '13

26 Feb '13

In 1.50, I introduced: template<typename InputIterator, typename OutputIterator, typename Predicate> OutputIterator copy_while ( InputIterator first, InputIterator last, OutputIterator result, Predicate p ); (and copy_until), which do pretty much what you would expect: copy items from the input to the output as long as the predicate holds. Sean Parent has convinced me that this is wrong; that I have to return the modified input iterator as well. When I wrote these, I was thinking (if I actually was thinking) of actual input iterators, and since they're all the same, so the caller can pick up on the input sequence after the call returns. However, if you're processing (say) a list, it would be kind of useful to know how far in the list the call advanced. I'm proposing to change the interface to: template<typename InputIterator, typename OutputIterator, typename Predicate> std::pair<InputIterator, OutputIterator> copy_while ( InputIterator first, InputIterator last, OutputIterator result, Predicate p ); i.e, changing the return type to return both iterators. What this means: * If you're not calling copy_while (or copy_until), then this change won't affect you. * If you're not using the return value, then this change won't affect you. * If you are using the return value, then you will have to change your code thus: Old foo = copy_while ( first, last, out, p ); New: foo = copy_while ( first, last, out, p ).second; * if you were not using these calls because they didn't return the input iterator, now you can. Questions? Comments? (Except for the "How could you miss that when you wrote those routines?" - I've already asked myself that) Improvements? -- 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

7 10

[context][iostreams] Cygwin Boost 1.53 error building some libraries.
by Mostafa 26 Feb '13

26 Feb '13

On Windows 7, cygwin 2.7, trying to build Boost 1.53 with the following options fails: ./b2.exe --layout=system --variant=release --link=static,shared --threading=single,multi install -j4 with the following errors: gcc.compile.asm bin.v2/libs/context/build/gcc-4.5.3/release/link-static/threading-multi/asm/make_i386_sysv_elf_gas.o libs/context/src/asm/make_i386_sysv_elf_gas.S: Assembler messages: libs/context/src/asm/make_i386_sysv_elf_gas.S:37: Warning: .type pseudo-op used outside of .def/.endef ignored. libs/context/src/asm/make_i386_sysv_elf_gas.S:37: Error: junk at end of line, first unrecognized character is `m' libs/context/src/asm/make_i386_sysv_elf_gas.S:77: Warning: .size pseudo-op used outside of .def/.endef ignored. libs/context/src/asm/make_i386_sysv_elf_gas.S:77: Error: junk at end of line, first unrecognized character is `m' gcc.archive bin.v2/libs/atomic/build/gcc-4.5.3/release/link-static/threading-multi/libboost_atomic.a "g++" -x assembler-with-cpp -O3 -finline-functions -Wno-inline -Wall -DBOOST_ALL_NO_LIB=1 -DNDEBUG -I"." -c -o "bin.v2/libs/context/build/gcc-4.5.3/release/link-static/threading-multi/asm/make_i386_sysv_elf_gas.o" "libs/context/src/asm/make_i386_sysv_elf_gas.S" ...failed gcc.compile.asm bin.v2/libs/context/build/gcc-4.5.3/release/link-static/threading-multi/asm/make_i386_sysv_elf_gas.o... common.copy /home/HPC/boost/v1_53_0/lib/libboost_atomic.a gcc.archive bin.v2/libs/system/build/gcc-4.5.3/release/link-static/threading-multi/libboost_system.a ... common.mkdir bin.v2/libs/date_time/build/gcc-4.5.3/release/link-static gcc.compile.asm bin.v2/libs/context/build/gcc-4.5.3/release/link-static/threading-multi/asm/jump_i386_sysv_elf_gas.o libs/context/src/asm/jump_i386_sysv_elf_gas.S: Assembler messages: libs/context/src/asm/jump_i386_sysv_elf_gas.S:37: Warning: .type pseudo-op used outside of .def/.endef ignored. libs/context/src/asm/jump_i386_sysv_elf_gas.S:37: Error: junk at end of line, first unrecognized character is `j' libs/context/src/asm/jump_i386_sysv_elf_gas.S:72: Warning: .size pseudo-op used outside of .def/.endef ignored. libs/context/src/asm/jump_i386_sysv_elf_gas.S:72: Error: junk at end of line, first unrecognized character is `j' "g++" -x assembler-with-cpp -O3 -finline-functions -Wno-inline -Wall -DBOOST_ALL_NO_LIB=1 -DNDEBUG -I"." -c -o "bin.v2/libs/context/build/gcc-4.5.3/release/link-static/threading-multi/asm/jump_i386_sysv_elf_gas.o" "libs/context/src/asm/jump_i386_sysv_elf_gas.S" ...failed gcc.compile.asm bin.v2/libs/context/build/gcc-4.5.3/release/link-static/threading-multi/asm/jump_i386_sysv_elf_gas.o... ...skipped <pbin.v2/libs/context/build/gcc-4.5.3/release/link-static/threading-multi>libboost_context.a(clean) for lack of <pbin.v2/libs/context/build/gcc-4.5.3/release/link-static/threading-multi>asm/make_i386_sysv_elf_gas.o... ...skipped <pbin.v2/libs/context/build/gcc-4.5.3/release/link-static/threading-multi>libboost_context.a for lack of <pbin.v2/libs/context/build/gcc-4.5.3/release/link-static/threading-multi>asm/make_i386_sysv_elf_gas.o... ... common.mkdir bin.v2/libs/locale/build/gcc-4.5.3/release/link-static common.mkdir bin.v2/libs/locale/build/gcc-4.5.3/release/link-static/threading-multi gcc.compile.c++ bin.v2/libs/iostreams/build/gcc-4.5.3/release/link-static/threading-multi/bzip2.o libs\iostreams\src\bzip2.cpp:20:56: fatal error: bzlib.h: No such file or directory compilation terminated. "g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -mthreads -DBOOST_ALL_NO_LIB=1 -DBOOST_IOSTREAMS_USE_DEPRECATED -DNDEBUG -I"." -c -o "bin.v2\libs\iostreams\build\gcc-4.5.3\release\link-static\threading-multi\bzip2.o" "libs\iostreams\src\bzip2.cpp" ...failed gcc.compile.c++ bin.v2/libs/iostreams/build/gcc-4.5.3/release/link-static/threading-multi/bzip2.o... ...skipped <pbin.v2/libs/iostreams/build/gcc-4.5.3/release/link-static/threading-multi>libboost_iostreams.a(clean) for lack of <pbin.v2/libs/iostreams/build/gcc-4.5.3/release/link-static/threading-multi>bzip2.o... ...skipped <pbin.v2/libs/iostreams/build/gcc-4.5.3/release/link-static/threading-multi>libboost_iostreams.a for lack of <pbin.v2/libs/iostreams/build/gcc-4.5.3/release/link-static/threading-multi>bzip2.o... ... ...failed updating 6 targets... ...skipped 14 targets... ...updated 3818 targets...

2 2

bjam compiler error
by Christian Henning 26 Feb '13

26 Feb '13

Hi, I'm getting an compiler error when I try to build gil::io documentation. ...patience... ...patience... ...found 1737 targets... ...updating 5 targets... compile-c-c++ ..\..\..\..\bin.v2\tools\quickbook\src\msvc-10.0\release\link-static\threading-multi\values.obj values.cpp C:\boost\tools\quickbook\src\values.cpp(444) : error C2593: 'operator ==' is ambiguous ..\..\..\..\boost/utility/string_ref.hpp(275): could be 'bool boost::operator ==<char,std::char_traits<char>>(boost::basic_string_ref<charT,traits>,boost::basic_string_ref<charT,traits>)' [found using argument-dependent lookup] with [ charT=char, traits=std::char_traits<char> ] ..\..\..\..\boost/utility/string_ref.hpp(270): or 'bool boost::operator ==<char,std::char_traits<char>>(boost::basic_string_ref<charT,traits>,boost::basic_string_ref<charT,traits>)' [found using argument-dependent lookup] with [ charT=char, traits=std::char_traits<char> ] ..\..\..\..\boost/utility/string_ref.hpp(265): or 'bool boost::operator ==<char,std::char_traits<char>>(boost::basic_string_ref<charT,traits>,boost::basic_string_ref<charT,traits>)' [found using argument-dependent lookup] with [ charT=char, traits=std::char_traits<char> ] while trying to match the argument list '(boost::string_ref, boost::string_ref)' C:\boost\tools\quickbook\src\values.cpp(499) : error C2593: 'operator ==' is ambiguous ..\..\..\..\boost/utility/string_ref.hpp(275): could be 'bool boost::operator ==<char,std::char_traits<char>>(boost::basic_string_ref<charT,traits>,boost::basic_string_ref<charT,traits>)' [found using argument-dependent lookup] with [ charT=char, traits=std::char_traits<char> ] ..\..\..\..\boost/utility/string_ref.hpp(270): or 'bool boost::operator ==<char,std::char_traits<char>>(boost::basic_string_ref<charT,traits>,boost::basic_string_ref<charT,traits>)' [found using argument-dependent lookup] with [ charT=char, traits=std::char_traits<char> ] ..\..\..\..\boost/utility/string_ref.hpp(265): or 'bool boost::operator ==<char,std::char_traits<char>>(boost::basic_string_ref<charT,traits>,boost::basic_string_ref<charT,traits>)' [found using argument-dependent lookup] with [ charT=char, traits=std::char_traits<char> ] while trying to match the argument list '(boost::string_ref, boost::string_ref)' call "C:\program files (x86)\microsoft visual studio 10.0\VC\vcvarsall.bat" x86 >nul cl /Zm800 -nologo @"..\..\..\..\bin.v2\tools\quickbook\src\msvc-10.0\release\link-static\threading-multi\values.obj.rsp" ...failed compile-c-c++ ..\..\..\..\bin.v2\tools\quickbook\src\msvc-10.0\release\link-static\threading-multi\values.obj... ...skipped <p..\..\..\..\bin.v2\tools\quickbook\src\msvc-10.0\release\link-static\threading-multi>quickbook.exe for lack of <p..\..\..\..\bin.v2\tools\quickbook\src\msvc-10.0\release\link-static\threading-multi>values.obj... ...skipped <p..\..\..\..\bin.v2\libs\gil\io\doc\msvc-10.0\debug\threading-multi>io.xml for lack of <p..\..\..\..\bin.v2\tools\quickbook\src\msvc-10.0\release\link-static\threading-multi>quickbook.exe... ...skipped <p..\..\..\..\bin.v2\libs\gil\io\doc\msvc-10.0\debug\threading-multi>io.docbook for lack of <p..\..\..\..\bin.v2\libs\gil\io\doc\msvc-10.0\debug\threading-multi-object(xinclude-scanner)@1505>io.xml... ...skipped <phtml>standalone_HTML.manifest for lack of <p..\..\..\..\bin.v2\libs\gil\io\doc\msvc-10.0\debug\threading-multi>io.docbook... ...failed updating 1 target... ...skipped 4 targets... Regards, Christian

5 5

[type_erasure] Some issues
by Fabio Fracassi 25 Feb '13

25 Feb '13

Hi Steven, I recently gave a presentation about type erasure in general, and your library in particular, at our local C++ UG (see here http://prezi.com/kg6d82f-_yky/type-erasure/ or the examples at https://github.com/CppUGBerlin/Talks/tree/master/2013_02_19_TypeErasure if you are interested). During the preparation I discovered some issues I'd like to ask you about. First I think I discovered a bug either in your lib or in clang(with libc++) when compiling one of the documentation examples in C++11 mode. #include <boost/type_erasure/any.hpp> #include <boost/type_erasure/any_cast.hpp> #include <boost/type_erasure/builtin.hpp> #include <boost/type_erasure/operators.hpp> #include <boost/type_erasure/tuple.hpp> #include <iostream> namespace bte = boost::type_erasure; namespace mpl = boost::mpl; int main() { typedef bte::any< mpl::vector< bte::copy_constructible<>, bte::typeid_<>, bte::addable<>, bte::ostreamable<> > > any_type; any_type x(10); any_type y(7); any_type z(x + y); std::cout << z << std::endl; } Compiling this in C++03 mode is fine, in C++11 mode it fails with this error: In file included from te_multi03.cpp:5: ../../Staging/type_erasure/boost/type_erasure/operators.hpp:187:1: error: no matching function for call to 'call' BOOST_TYPE_ERASURE_BINARY_OPERATOR(addable, +) see [1] below for full error. The next are some things which I didn't get to work, and the documentation is silent on any pitfalls. I tried to implement Sean Parent's example from his Value Semantics talk and failed to write a concept that calls free functions instead of members. Here is what I tried (full code and error at [2] below): template<class OBJ, class T> struct drawable { static void apply(const OBJ& obj, T& os, size_t pos) { draw(obj, os, pos); } }; I get an error like: error call to function 'draw' that is neither visible in the template definition nor found by argument-dependent lookup I worked around this problem by defining a concept map, but that is not realy a good solution. On researching a better solution I saw that you already added the convenience macros BOOST_TYPE_ERASURE_MEMBER and BOOST_TYPE_ERASURE_FREE, but didn't have much luck with them. Is there a compileable example where they are used somewhere? Best regards Fabio **** [1] *************************************************************** [1] full error docu example: In file included from te_multi03.cpp:5: ../../Staging/type_erasure/boost/type_erasure/operators.hpp:187:1: error: no matching function for call to 'call' BOOST_TYPE_ERASURE_BINARY_OPERATOR(addable, +) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ../../Staging/type_erasure/boost/type_erasure/operators.hpp:166:20: note: expanded from macro 'BOOST_TYPE_ERASURE_BINARY_OPERATOR' return ::boost::type_erasure::call(name<T, U, R>(), lhs, rhs); \ ^~~~~~~~~~~~~~~~~~~~~~~~~~~ te_multi03.cpp:25:17: note: in instantiation of member function 'boost::type_erasure::operator+' requested here any_type z(x + y); ^ ../../Staging/type_erasure/boost/type_erasure/call.hpp:323:1: note: candidate template ignored: failed template argument deduction call( ^ ../../Staging/type_erasure/boost/type_erasure/call.hpp:356:1: note: candidate template ignored: substitution failure [with Op = boost::type_erasure::addable<boost::type_erasure::_self, boost::type_erasure::_self, boost::type_erasure::_self>, U = <const boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, boost::type_erasure::typeid_<boost::type_erasure::_self>, boost::type_erasure::addable<boost::type_erasure::_self, boost::type_erasure::_self, boost::type_erasure::_self>, boost::type_erasure::ostreamable<std::__1::basic_ostream<char>, boost::type_erasure::_self>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self>, boost::type_erasure::param<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, boost::type_erasure::typeid_<boost::type_erasure::_self>, boost::type_erasure::addable<boost::type_erasure::_self, boost::type_erasure::_self, boost::type_erasure::_self>, boost::type_erasure::ostreamable<std::__1::basic_ostream<char>, boost::type_erasure::_self>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, const boost::type_erasure::_self &>>]: no type named 'type' in 'boost::type_erasure::detail::call_result<boost::type_erasure::addable<boost::type_erasure::_self, boost::type_erasure::_self, boost::type_erasure::_self>, void (const boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, boost::type_erasure::typeid_<boost::type_erasure::_self>, boost::type_erasure::addable<boost::type_erasure::_self, boost::type_erasure::_self, boost::type_erasure::_self>, boost::type_erasure::ostreamable<std::__1::basic_ostream<char>, boost::type_erasure::_self>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self> &, boost::type_erasure::param<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, boost::type_erasure::typeid_<boost::type_erasure::_self>, boost::type_erasure::addable<boost::type_erasure::_self, boost::type_erasure::_self, boost::type_erasure::_self>, boost::type_erasure::ostreamable<std::__1::basic_ostream<char>, boost::type_erasure::_self>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, const boost::type_erasure::_self &> &), void>' call( ^ 1 error generated. **** [2] *************************************************************** [2] Code and error for Value semantic example: #include <boost/type_erasure/any.hpp> #include <boost/type_erasure/concept_interface.hpp> #include <boost/type_erasure/rebind_any.hpp> #include <boost/type_erasure/free.hpp> #include <vector> namespace bte = boost::type_erasure; namespace mpl = boost::mpl; //-------------------------------------------------------------------------------------------------- template<class OBJ, class T> struct drawable { static void apply(const OBJ& obj, T& os, size_t pos) { draw(obj, os, pos); } }; namespace boost { namespace type_erasure { template<class OBJ, class T, class Base> struct concept_interface< ::drawable<OBJ, T>, Base, OBJ> : Base { void draw(typename rebind_any<Base, T&>::type os, size_t pos) const { call(::drawable<OBJ, T>(), *this, os, pos); } }; } } using object_t = bte::any< mpl::vector< bte::copy_constructible<>, drawable<bte::_self, std::ostream> >>; //-------------------------------------------------------------------------------------------------- void draw(const int& value, std::ostream& out, size_t position) { out << std::string(position, ' ') << "int = " << value << std::endl; } void draw(const std::string& value, std::ostream& out, size_t position) { out << std::string(position, ' ') << "string = " << value << std::endl; } struct my_class_t {}; void draw(const my_class_t&, std::ostream& out, size_t position) { out << std::string(position, ' ') << "my_class_t" << std::endl; } //-------------------------------------------------------------------------------------------------- using document_t = std::vector<object_t>; // or std::vector<copy_on_write<object_t>>; void draw(const document_t& x, std::ostream& out, size_t position) { out << std::string(position, ' ') << "<document>" << std::endl; for (auto& e : x) { e.draw(out, position + 2); } out << std::string(position, ' ') << "</document>" << std::endl; } //-------------------------------------------------------------------------------------------------- using history_t = std::vector<document_t>; void commit(history_t& x) { assert(x.size()); x.push_back(x.back()); } void undo(history_t& x) { assert(x.size()); x.pop_back(); } document_t& current(history_t& x) { assert(x.size()); return x.back(); } //-------------------------------------------------------------------------------------------------- int main () { history_t h(1); current(h).emplace_back(0); current(h).emplace_back(std::string("Hello!")); draw(current(h), std::cout, 0); std::cout << "--------------------------" << std::endl; commit(h); current(h).emplace_back(current(h)); current(h).emplace_back(my_class_t()); draw(current(h), std::cout, 0); std::cout << "--------------------------" << std::endl; undo(h); draw(current(h), std::cout, 0); } **** Error: ************************************************************ te_sp_copy.cpp:14:59: error: call to function 'draw' that is neither visible in the template definition nor found by argument-dependent lookup static void apply(const OBJ& obj, T& os, size_t pos) { draw(obj, os, pos); } ^ ../../Staging/type_erasure/boost/type_erasure/detail/instantiate.hpp:91:28: note: in instantiation of member function 'drawable<int, std::__1::basic_ostream<char> >::apply' requested here BOOST_PP_REPEAT(N, BOOST_TYPE_ERASURE_INSTANTIATE_IMPL, concept_sequence) ^ /usr/local/include/boost/preprocessor/repetition/repeat.hpp:38:60: note: expanded from macro 'BOOST_PP_REPEAT_1' # define BOOST_PP_REPEAT_1(c, m, d) BOOST_PP_REPEAT_1_I(c, m, d) ^ /usr/local/include/boost/preprocessor/repetition/repeat.hpp:43:63: note: expanded from macro 'BOOST_PP_REPEAT_1_I' # define BOOST_PP_REPEAT_1_I(c, m, d) BOOST_PP_REPEAT_1_ ## c(m, d) ^ /usr/local/include/boost/preprocessor/repetition/repeat.hpp:54:62: note: expanded from macro 'BOOST_PP_REPEAT_1_3' # define BOOST_PP_REPEAT_1_3(m, d) BOOST_PP_REPEAT_1_2(m, d) m(2, 2, d) ^ ../../Staging/type_erasure/boost/type_erasure/detail/instantiate.hpp:70:47: note: expanded from macro 'BOOST_TYPE_ERASURE_INSTANTIATE_IMPL' (void)&::boost::mpl::at_c<data, n>::type::apply; ^ ../../Staging/type_erasure/boost/type_erasure/any.hpp:182:13: note: in instantiation of function template specialization 'boost::type_erasure::detail::instantiate_concept3::apply<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::mpl::map1<boost::mpl::pair<boost::type_erasure::_self, int> > >' requested here BOOST_TYPE_ERASURE_INSTANTIATE1(Concept, T, U), ^ ../../Staging/type_erasure/boost/type_erasure/detail/instantiate.hpp:51:14: note: expanded from macro 'BOOST_TYPE_ERASURE_INSTANTIATE1' >::type::apply( \ ^ /usr/bin/../lib/c++/v1/memory:1681:31: note: in instantiation of function template specialization 'boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self>::any<int>' requested here ::new((void*)__p) _Up(_VSTD::forward<_Args>(__args)...); ^ /usr/bin/../lib/c++/v1/memory:1608:18: note: in instantiation of function template specialization 'std::__1::allocator<boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self> >::construct<boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self>, int>' requested here {__a.construct(__p, _VSTD::forward<_Args>(__args)...);} ^ /usr/bin/../lib/c++/v1/memory:1492:14: note: in instantiation of function template specialization 'std::__1::allocator_traits<std::__1::allocator<boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self> > >::__construct<boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self>, int>' requested here {__construct(__has_construct<allocator_type, pointer, _Args...>(), ^ /usr/bin/../lib/c++/v1/vector:1519:25: note: in instantiation of function template specialization 'std::__1::allocator_traits<std::__1::allocator<boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self> > >::construct<boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self>, int>' requested here __alloc_traits::construct(this->__alloc(), ^ te_sp_copy.cpp:71:15: note: in instantiation of function template specialization 'std::__1::vector<boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self>, std::__1::allocator<boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self> > >::emplace_back<int>' requested here current(h).emplace_back(0); ^ te_sp_copy.cpp:33:6: note: 'draw' should be declared prior to the call site void draw(const int& value, std::ostream& out, size_t position) { ^ te_sp_copy.cpp:14:59: error: call to function 'draw' that is neither visible in the template definition nor found by argument-dependent lookup static void apply(const OBJ& obj, T& os, size_t pos) { draw(obj, os, pos); } ^ ../../Staging/type_erasure/boost/type_erasure/detail/instantiate.hpp:91:28: note: in instantiation of member function 'drawable<std::__1::basic_string<char>, std::__1::basic_ostream<char> >::apply' requested here BOOST_PP_REPEAT(N, BOOST_TYPE_ERASURE_INSTANTIATE_IMPL, concept_sequence) ^ /usr/local/include/boost/preprocessor/repetition/repeat.hpp:38:60: note: expanded from macro 'BOOST_PP_REPEAT_1' # define BOOST_PP_REPEAT_1(c, m, d) BOOST_PP_REPEAT_1_I(c, m, d) ^ /usr/local/include/boost/preprocessor/repetition/repeat.hpp:43:63: note: expanded from macro 'BOOST_PP_REPEAT_1_I' # define BOOST_PP_REPEAT_1_I(c, m, d) BOOST_PP_REPEAT_1_ ## c(m, d) ^ /usr/local/include/boost/preprocessor/repetition/repeat.hpp:54:62: note: expanded from macro 'BOOST_PP_REPEAT_1_3' # define BOOST_PP_REPEAT_1_3(m, d) BOOST_PP_REPEAT_1_2(m, d) m(2, 2, d) ^ ../../Staging/type_erasure/boost/type_erasure/detail/instantiate.hpp:70:47: note: expanded from macro 'BOOST_TYPE_ERASURE_INSTANTIATE_IMPL' (void)&::boost::mpl::at_c<data, n>::type::apply; ^ ../../Staging/type_erasure/boost/type_erasure/any.hpp:182:13: note: in instantiation of function template specialization 'boost::type_erasure::detail::instantiate_concept3::apply<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::mpl::map1<boost::mpl::pair<boost::type_erasure::_self, std::__1::basic_string<char> > > >' requested here BOOST_TYPE_ERASURE_INSTANTIATE1(Concept, T, U), ^ ../../Staging/type_erasure/boost/type_erasure/detail/instantiate.hpp:51:14: note: expanded from macro 'BOOST_TYPE_ERASURE_INSTANTIATE1' >::type::apply( \ ^ /usr/bin/../lib/c++/v1/memory:1681:31: note: in instantiation of function template specialization 'boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self>::any<std::__1::basic_string<char> >' requested here ::new((void*)__p) _Up(_VSTD::forward<_Args>(__args)...); ^ /usr/bin/../lib/c++/v1/memory:1608:18: note: in instantiation of function template specialization 'std::__1::allocator<boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self> >::construct<boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self>, std::__1::basic_string<char> >' requested here {__a.construct(__p, _VSTD::forward<_Args>(__args)...);} ^ /usr/bin/../lib/c++/v1/memory:1492:14: note: in instantiation of function template specialization 'std::__1::allocator_traits<std::__1::allocator<boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self> > >::__construct<boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self>, std::__1::basic_string<char> >' requested here {__construct(__has_construct<allocator_type, pointer, _Args...>(), ^ /usr/bin/../lib/c++/v1/vector:1519:25: note: in instantiation of function template specialization 'std::__1::allocator_traits<std::__1::allocator<boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self> > >::construct<boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self>, std::__1::basic_string<char> >' requested here __alloc_traits::construct(this->__alloc(), ^ te_sp_copy.cpp:72:15: note: in instantiation of function template specialization 'std::__1::vector<boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self>, std::__1::allocator<boost::type_erasure::any<boost::mpl::vector<boost::type_erasure::copy_constructible<boost::type_erasure::_self>, drawable<boost::type_erasure::_self, std::__1::basic_ostream<char> >, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::type_erasure::_self> > >::emplace_back<std::__1::basic_string<char> >' requested here current(h).emplace_back(std::string("Hello!")); ^ te_sp_copy.cpp:37:6: note: 'draw' should be declared prior to the call site void draw(const std::string& value, std::ostream& out, size_t position) { ^ 2 errors generated.

2 3

[gil::io] Feedback for scanline_read_iterator
by Christian Henning 25 Feb '13

25 Feb '13

Hi all, I'm getting close to finally commit the new io extension for boost::gil. As it was required from the boost review I have implemented a basic image_read_iterator to read large images. I would like to get some feedback on my interface and maybe on the actual implementation, as well. I must admit this is my first iterator that I have designed and implemented from scratch with some help by other people. The latest io code can be found here via svn: http://code.google.com/p/gil-contributions/source/browse/#svn%2Ftrunk%2Fgil… A basic usage of the code is here: http://pastebin.com/3E7KpfwE Thanks! Christian

7 51

[utility]proposal for a small utility of namespace
by law chrono 25 Feb '13

25 Feb '13

I like c++ and boost，but write namespace is a boring work for brace-matching. So I write a small util with boost.preprocessor, like below: #ifndef BOOST_NAMESPACE_UTILITY_HPP_ #define BOOST_NAMESPACE_UTILITY_HPP_ #include <boost/preprocessor/seq/for_each.hpp> #define _PP_NS_BEGIN_FUNC(r,data,elem) namespace elem { #define _PP_NS_END_FUNC(r,data,elem) } #define BOOST_BEGIN_NAMESPACE(SEQ) \ BOOST_PP_SEQ_FOR_EACH(_PP_NS_BEGIN_FUNC, ~, SEQ) #define BOOST_ END_ NAMESPACE (SEQ) \ BOOST_PP_SEQ_FOR_EACH(_PP_NS_END_FUNC, ~, SEQ) #endif //BOOST_NAMESPACE_UTILITY_HPP_ Then the code can be more clear and easy-reading: BOOST_BEGIN_NAMESPACE((boost)(asio)(ip)) //namespace boost{namespace asio{namespace ip{ ... //to something BOOST_END_NAMESPACE((boost)(asio)(ip)) //}}} c++11 inline namespace also can work: inline BOOST_BEGIN_NAMESPACE((detail)) ... //to something BOOST_END_NAMESPACE((detail)) I wander to know whether this util could be a part of boost. Thanks a lot.

3 2

[thread|shared_ptr|atomic] segmentation fault in exception_ptr assignment
by Oliver Kowalke 24 Feb '13

24 Feb '13

I've replaced shared_ptr<> by intrusive_ptr<> + atomic< std::size_t > in boost.thread's future implementation. atomic< std::size_t > use_count; // initialized with '0' in ctor friend inline void intrusive_ptr_add_ref( future_continuation_base * p) BOOST_NOEXCEPT { ++p->use_count; // should be seq_cst } friend inline void intrusive_ptr_release( future_continuation_base * p) { if ( 0 == --p->use_count) // should be seq_cst delete p; } I get an error if I compile the code with gcc-4.7.2 on x86_64: segmentation fault backtrace: 0x0000000000426a96 in boost::detail::atomic_exchange_and_add (pw=0x436a40, dv=-1) at ../../../boost/smart_ptr/detail/sp_counted_base_gcc_x86.hpp:50 50 ); (gdb) bt #0 0x0000000000426a96 in boost::detail::atomic_exchange_and_add (pw=0x436a40, dv=-1) at ../../../boost/smart_ptr/detail/sp_counted_base_gcc_x86.hpp:50 #1 0x0000000000426ba7 in boost::detail::sp_counted_base::release (this=0x436a38) at ../../../boost/smart_ptr/detail/sp_counted_base_gcc_x86.hpp:143 #2 0x0000000000426c57 in boost::detail::shared_count::~shared_count (this=0x7fffffffc868, __in_chrg=<optimized out>) at ../../../boost/smart_ptr/detail/shared_count.hpp:368 #3 0x0000000000427c3e in boost::shared_ptr<boost::exception_detail::clone_base const>::~shared_ptr (this=0x7fffffffc860, __in_chrg=<optimized out>) at ../../../boost/smart_ptr/shared_ptr.hpp:316 #4 0x000000000042b2cd in boost::shared_ptr<boost::exception_detail::clone_base const>::operator= (this=0x75df00, r=...) at ../../../boost/smart_ptr/shared_ptr.hpp:485 #5 0x0000000000427d6f in boost::exception_ptr::operator= (this=0x75df00, other=...) at ../../../boost/exception/detail/exception_ptr.hpp:73 #6 0x0000000000429a2f in boost::fibers::detail::future_object_base::mark_exceptional_finish_internal (this=0x75def0, e=..., lock=...) at ../../../boost/fiber/future.hpp:278 #7 0x000000000043749a in boost::fibers::detail::task_base<int>::owner_destroyed (this=0x75def0) at ../../../boost/fiber/future.hpp:1241 #8 0x000000000042e768 in boost::fibers::packaged_task<int>::~packaged_task (this=0x7fffffffc9b0, __in_chrg=<optimized out>) at ../../../boost/fiber/future.hpp:1341 called funtions: ~packaged_task() -> task_base::owner_destroyed() -> future_object_base::mark_exceptional_finish_internal() -> exception_ptr::operator=(excepton_ptr const&) -> shared_ptr -> shared_count -> sp_counted_base_gcc_x86 -> boost::detail::atomic_exchange_and_add() I'm wondering why a simple assignement of excpetion_ptr causes a segmentation fault if future's implementation uses intrusive_ptr + atomic + sequential - consistent ops instead of shared_ptr. Does someone have an explanation?

2 1

[thread] ~condition_variable_any verifications
by Tim Blechmann 24 Feb '13

24 Feb '13

hi, one of my project uses exit() to terminate the program. this is sometimes called while some threads are waiting on a global condition_variable_any. when calling exit(), this global variable is destroyed while other threads are still waiting on it, which causes BOOST_VERIFY to fire an assertion failure !pthread_cond_destroy(&cond). this scares the hell out of my users. i know that these verifications can be really useful in many case, but in my use case, it makes exit() rather unusable, and i'd have to redesign some of the internal logic to avoid this assertion failure. thoughts? thnx, tim

4 5