September 2016 - Boost-users - lists.preview.boost.org

[Interprocess]: using condition variables with readers-writer lock (named_sharable_mutex)
by Chris Evans 21 Sep '16

21 Sep '16

Hi, I am trying to use condition variables to signify updated data in a managed_shared_memory segment. I have one "writer" and multiple "readers" of the shared state, so I am using a readers-writer lock as follows: using SharedMutex = bi::named_sharable_mutex; using ReadLock = bi::sharable_lock<SharedMutex>; using WriteLock = bi::scoped_lock<SharedMutex>; using NewEntryCondition = bi::named_condition_any; // With a "writer" block as follows: { WriteLock w_lock( sh_mut_ ); // Update the shared memory object sh_cond_.notify_all(); } // And a "reader" block as follows (many processes call the following simultaneously): { ReadLock r_lock( sh_mut_ ); sh_cond_.wait( r_lock, []() { std::cout << "checking predicate..." << std::endl; // predicate logic goes here... }); // Access object in shared memory here } Unfortunately, although the code compiles, the reader processes are never awakened from wait() and block forever. According to the following thread from 2011: http://lists.boost.org/boost-users/2011/02/66053.php "POSIX does not support condition variables with read-write locks (although I think Windows Vista does) so Interprocess does not offer any support for this." At the time, it appears named_condition_any didn't yet exist. Has the status of this changed in the last 5 years? Is there a suggested way of implementing readers-writer locks with condition variables using boost::interprocess? Thanks! -- Chris Evans Systems Engineer Azure Summit Technology, Inc. 3050 Chain Bridge Road, Suite 600 Fairfax, VA 22030

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[compute] extending meta_kernel functionality
by Oswin Krause 20 Sep '16

20 Sep '16

Hi, I am trying to use boost.compute to extend my linear algebra library to GPUs. so far it helped me a lot with vectors as i can directly use the iterator interface. Matrices are harder. for matrices i need to overload the operator matrix(i,j)-> return the element (i,j). For this i have to return an expression which then offers operator<< with meta_kernel, for example template<class T, class IndexExpr1, class IndexExpr2> inline meta_kernel& operator<<(boost::compute::detail::meta_kernel &kernel, const matrix_element_expr<T, IndexExpr1, IndexExpr2> &expr) { return kernel << kernel.get_buffer_identifier<T>(expr.m_buffer, expr.m_address_space) << '[' << expr.m_expr1 <<"*" <<expr.m_stride1<<"+"<<expr.m_expr2<< "*"<<expr.m_stride2 << ']'; } Unfortunately all of this is in namespace boost::compute::detail, making it a no-go area. Therefore two questions: 1. How stable is i?/can meta_kernel be moved into a normal namespace? 2. Is there a different way to achieve this? (Note that the code above is only an example. I could hack it in this case using the return type of buffer_iterator but not in all cases unfortunately...)

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boost::context "main" stack
by Michael Steinberg 20 Sep '16

20 Sep '16

Hello, is there some way to temporarily run a function on the main stack? I played around a bit, but failed ultimately since the first stub function to be called is getting a "null" context which I assume to be only a valid "return-context". We're facing a problem where a dialog run modally inside a context runs webkit, which triggers garbage collection, which fails miserably since it assumes we're on the "native" stack. If it were possible to run something "on-top" of the main stack, this could maybe be circumvented. Thank you, Michael

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Insertion/Use of boost::multi_index
by Ram 19 Sep '16

19 Sep '16

Hi All , I have created a boost::multi_index container for my use and it compiles successfully. I would like to add my pointer objects to it. boost::multi_index does not seem to have an insert method defined which just takes one arguement which is what I would like the container to store. Maybe I didnt understand how boost::multi_index is meant to be used. Can you please explain to me how to insert an object which I wish the store in the container defined? How is it intended to be used? The container I defined is , typedef boost::multi_index_ClassX< ClassX*, boost::multi_index::indexed_by< boost::multi_index::hashed_unique< boost::multi_index::const_mem_fun<ParentOfClassX, Int64, &ParentOfClassX::getKey1>, boost::multi_index::const_mem_fun<ParentOfClassX, Int64, &ParentOfClassX::getKey2>, > > > MultiIndexedClassX; I would like to do an equivalent of, MultiIndexedClassX sample; ClassX a; sample.insert(&a); <- Since I am interested in storing a *X and I would like it to be indexed by various parameters of X. Also please let me know how to, 1. Insert *X into the container 2. Look up by a) Value of ParentOfClassX::Key1 b) Value of ParentOfClassX::Key2 Please also let me know if I have some basic understanding wrong since I am getting confused a lot in trying to use boost::multi_index. Thanks in advance, Ram

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Help Required, trouble while using boost::multi_index
by Ram 19 Sep '16

19 Sep '16

Hi, I am trying to create a ClassX using "boost::multi_index" and I was successfully able to create a ClassX like, typedef boost::multi_index_ClassX< ClassX*, boost::multi_index::indexed_by< boost::multi_index::hashed_unique< boost::multi_index::const_mem_fun<ParentOfClassX, Int64, &ParentOfClassX::getKey1>, boost::multi_index::const_mem_fun<ParentOfClassX, Int64, &ParentOfClassX::getKey2>, > > > MultiIndexedClassX; This compiles perfectly with no problems. I am writing the code and compiling with Visual Studio 2005 and have included, #include <boost/multi_index_container.hpp> #include "boost/multi_index/hashed_index_fwd.hpp" #include <boost/multi_index/mem_fun.hpp> and have defined namespaces, using namespace boost::multi_index; using boost::multi_index::multi_index_container; using boost::multi_index::hashed_unique; using boost::multi_index::indexed_by; But when I create an object of that type like, MultiIndexedClassX sample; I get a big list compilation errors like, *c:\code\common\lib\boost\boost\multi_index\detail\node_type.hpp(44) : error C2903: 'node_class' : symbol is neither a class template nor a function template* * c:\code\common\lib\boost\boost\mpl\aux_\preprocessed\plain\apply_wrap.hpp(49) : see reference to class template instantiation 'boost::multi_index::detail::index_node_applier::apply<IndexSpecifierIterator,Super>' being compiled* * with* * [* * IndexSpecifierIterator=boost::mpl::v_iter<boost::mpl::vector1<boost::multi_index::hashed_unique<boost::multi_index::const_mem_fun<ParentOfClassX,GKey,ParentOfClassX::getKey1>,boost::multi_index::const_mem_fun<ParentOfClassX,Vs64,ParentOfClassX::getKey2>>>,0>,* * Super=boost::multi_index::detail::index_node_base<ClassX *,std::allocator<ClassX *>>* * ]* * c:\code\common\lib\boost\boost\mpl\aux_\preprocessed\plain\bind.hpp(207) : see reference to class template instantiation 'boost::mpl::apply_wrap2<F,T1,T2>' being compiled* * with* * [* * F=boost::multi_index::detail::index_node_applier,* * T1=boost::mpl::v_iter<boost::mpl::vector1<boost::multi_index::hashed_unique<boost::multi_index::const_mem_fun<ParentOfClassX,GKey,ParentOfClassX::getKey1>,boost::multi_index::const_mem_fun<ParentOfClassX,Vs64,ParentOfClassX::getKey2>>>,0>,* * T2=boost::multi_index::detail::index_node_base<ClassX *,std::allocator<ClassX *>>* * ]* * c:\code\common\lib\boost\boost\mpl\aux_\preprocessed\plain\apply_wrap.hpp(49) : see reference to class template instantiation 'boost::mpl::bind2<F,T1,T2>::apply<U1,U2>' being compiled* * with* * [* * F=boost::multi_index::detail::index_node_applier,* * T1=boost::mpl::_2,* * T2=boost::mpl::_1,* * U1=boost::multi_index::detail::index_node_base<ClassX *,std::allocator<ClassX *>>,* * U2=boost::mpl::v_iter<boost::mpl::vector1<boost::multi_index::hashed_unique<boost::multi_index::const_mem_fun<ParentOfClassX,GKey,ParentOfClassX::getKey1>,boost::multi_index::const_mem_fun<ParentOfClassX,Vs64,ParentOfClassX::getKey2>>>,0>* * ]* * c:\code\common\lib\boost\boost\mpl\aux_\preprocessed\plain\apply.hpp(63) : see reference to class template instantiation 'boost::mpl::apply_wrap2<F,T1,T2>' being compiled* * with* * [* * F=boost::mpl::bind2<boost::multi_index::detail::index_node_applier,boost::mpl::_2,boost::mpl::_1>,* * T1=boost::multi_index::detail::index_node_base<ClassX *,std::allocator<ClassX *>>,* * T2=boost::mpl::v_iter<boost::mpl::vector1<boost::multi_index::hashed_unique<boost::multi_index::const_mem_fun<ParentOfClassX,GKey,ParentOfClassX::getKey1>,boost::multi_index::const_mem_fun<ParentOfClassX,Vs64,ParentOfClassX::getKey2>>>,0>* * ]* * c:\code\common\lib\boost\boost\mpl\aux_\preprocessed\plain\reverse_iter_fold_impl.hpp(58) : see reference to class template instantiation 'boost::mpl::apply2<F,T1,T2>' being compiled* * with* * [* * F=boost::mpl::bind2<boost::multi_index::detail::index_node_applier,boost::mpl::_2,boost::mpl::_1>,* * T1=boost::multi_index::detail::index_node_base<ClassX *,std::allocator<ClassX *>>,* * T2=boost::mpl::v_iter<boost::mpl::vector1<boost::multi_index::hashed_unique<boost::multi_index::const_mem_fun<ParentOfClassX,GKey,ParentOfClassX::getKey1>,boost::multi_index::const_mem_fun<ParentOfClassX,Vs64,ParentOfClassX::getKey2>>>,0>* * ]* Thanks, Ram

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[Graph] Is there an active maintainer for Boost.Graph?
by Rohan Shah 19 Sep '16

19 Sep '16

Hi all. I'm wondering whether Boost.Graph currently has an active maintainer. I only ask because there is a fairly active github repository ( https://github.com/boostorg/graph) but it seems that important commits fail to make it into the main release on the website. For example, I would consider this (https://github.com/boostorg/graph/commit/ 8ece8fac15560cf38cf3ffbb1d56708ef8e586a2) commit to be fairly critical - Without it part of depth_first_search seems to be somewhat broken, and that's a core algorithm. And that commit is from 2014! A conversation on #boost IRC suggested I mention this problem here. Note: I am not volunteering myself to help fix this - I'm simply not qualified for it. Sorry.

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[boost] [bjam] combinations of options
by Lorenzo Caminiti 19 Sep '16

19 Sep '16

Hello all, When I use bjam the following will compile my code with combinations of MSVC, GCC, and CLang for both shared and static linking: $ bjam toolset=msvc,gcc,clang link=shared,static # (1) Is there a way to define a variant, target, or something else in the Jamfiles so that I can shortcut the above by typing just the variant target at the command line: $ bjam all_toolset_link_combinations # equivalent to (1) above I am asking this just for convenience because I have a feature like toolset but with 30+ values so it'd be nice to shortcut it to a single target on the bjam command line. Thank you. --Lorenzo

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[test] Init framework before dataset generation
by Florian Lindner 16 Sep '16

16 Sep '16

Hello, I try to use boost test with data test cases: std::vector<float> fibonacci() { std::cout << "Data Set" << std::endl; [...] } BOOST_DATA_TEST_CASE(datatest, boost::unit_test::data::make(fibonacci()), mapping) { std::cout << "Datatype" << typeid(mapping).name() << std::endl; } The problem of that is, that fibonacci is initialized before anything else. The order of initializations is: Data Set main init_unit_test Global Fixture That works fine here, but my fibonacci uses MPI which needs to initialized by MPI_Init. I want to do that initialization in the global fixture or int main or init_unit_tests, once for the entire test runner. Is there anything I can do about that and belay initialization of Data Set after one of the others? Thanks, Florian

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[release] Boost 1.62.0. Beta 2
by Rene Rivera 14 Sep '16

14 Sep '16

The packages for 1.62.0 beta 2 are now available: <https://sourceforge.net/projects/boost/files/boost/1.62.0.beta.2/> The SHA256 checksums are as follows: 95feae3620b3e604e93f14d97195fc04a4b67063692859af8df19657d41b82d5 boost_1_62_0_b2.7z 27bc9b328ff73d7dbf80cd9d4b5f79b0878221e5d8e4b6c47444b135edc1080a boost_1_62_0_b2.tar.bz2 3939d5efa683449e87b374d7e92e3eeb6490063ddb2877919f0fad26e3a0f53e boost_1_62_0_b2.tar.gz cff9ab5db0928244c4c836cf3da5140e6e93db7756e2791ba99a21104ad3aa72 boost_1_62_0_b2.zip As always, the release managers would appreciate it if you download the archive of your choice and give building and using it a try. Please report both success and failure, and anything else that is noteworthy. Thanks! -- The release managers -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net -- rrivera/acm.org (msn) - grafikrobot/aim,yahoo,skype,efnet,gmail

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[Boost.Graph] Accessing underlying graph of a boost::reverse_graph
by Björn Pollex 13 Sep '16

13 Sep '16

Hello, I am currently trying to find out if there is a way to access the underlying graph of a boost::reverse_graph [1]. There does not seem to be support for this. I want to use this to generically define interior edge-properties for reversed graphs, if the underlying graph has them as well. Currently this does not work, because I cannot access the underlying graph object. Am I overlooking something? If not, where could I request to add this? Cheers, Björn Pollex [1]: http://www.boost.org/doc/libs/release/libs/graph/doc/reverse_graph.html

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[boost][interprocess] named_mutex/named_condition using windows shared memory
by Rob Conde 12 Sep '16

12 Sep '16

For boost interprocess shared memory, I can choose to use windows specific shared memory so that no files are created to emulate the functionality. Is there any way to do this with named_mutexes and named_conditions? Thanks, Rob Conde

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[release] Boost 1.62.0 Beta 1
by Rene Rivera 12 Sep '16

12 Sep '16

The first beta packages for 1.62.0 beta 1 are now available: <https://sourceforge.net/projects/boost/files/boost/1.61.0.beta.1/> The SHA256 checksums are as follows: f7cc83e6a3b03cd7aa8822992aa3e36422cc2214644d69277ef55a4db51f44bd boost_1_62_0_b1.7z 4057993811e40b1fd4719675e44c2550b6c2379546192da2299c17fec9a3dddf boost_1_62_0_b1.tar.bz2 fb0c10b625c5ec47cc837b54740540e400c59571b2eabf427c00f32bffc6ca70 boost_1_62_0_b1.tar.gz b38ef21c43c5ff814a2144bc23871c134164e7f51c71672d0f49a44636fb50b5 boost_1_62_0_b1.zip As always, the release managers would appreciate it if you download the archive of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. Thanks! -- The release managers -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net -- rrivera/acm.org (msn) - grafikrobot/aim,yahoo,skype,efnet,gmail

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"Re: [boost] Boost-1.62: How to get list of all dirs under 'run-tests libs:' target from status/Jamfile?"
by Sergey Sprogis 09 Sep '16

09 Sep '16

This is nice idea, but unfortunately does not work for my purpose of calculatingpass rates for every test suite of regression testing. It would fit perfectly if instead of ---dumptest b2 will also have another option, something like: --dumptestdirs. I mean, the option which generates the whole list of dirs containing all jamfiles executed for full regression testing. Actually, I spent some time trying to generate such list of dirs based on the output produced by 'b2 -n -a -d0 --dump-tests', but was not able to find general algorithm [ wout using specific library names and whout parsing the content of jamfiles ] which transforms list of tests into the list of test dirs from which they are launched [ assuming that each test should be executed only once ]. Here just couple of examples which demonstarte those difficulties: 1. In 'wave' its 'test' subdir does not contain jamfile like many other libsdo, but rather wave's jamfile is located inside internal 'build' subdirectory, and it launches testslocated from 'testlexers' 'testwave' subdirs which are located on the same level as 'build' itself. When my script sees those wave tests from --dumptest output, how should it figure out that jamfile which launches them is located inside 'build' dir? 2. Inside 'unordered' library there are two subdirs with jamfiles: test/exception and test/unordered. All tests for 'unordered' may be run in two similar ways: either by executing both those jamfiles, or by executing jamfile which is located on higher level inside 'test' subdir. But to run every test once the script should choose one or another way. Now, in a similar situation for 'core' library, in order to run all its tests one time my script should run both jamfiles: internal one located inside core/test, and also another one located in core/test/swap. How the script should resolve such ambiguity for 'unordered' and core' libraries? So, I think that list of test dirs which was present in status/Jamfile.v2 in boost-1.61.0 was really useful to me. But, of course if it was created manually, and there is no easy way to do it automatically, then probably, I should also create it manually for Boost-1.62 and all later versions. Sergey > 2016-09-04 11:45:41 Rene Rivera (/grafikrobot_at_[hidden]/) > wrote: > You can get a list of all the tests that get, or will get, run from b2 with the following: > % cd boost-root/status > % b2 -n -a -d0 --dump-tests > That will produce, interspersed with other output, lines like the following: > boost-test(RUN) "accumulators/count" : "libs/accumulators/test/count.cpp" > One of those for each test that is tested. The format is: > boost-test(<TYPE>) "<LIBRARY>/<TEST>" : "<SOURCE>" > Where LIBRARY can be of the form "<library>" or "<library>/<sublibrary>". > That should be sufficient to produce the results you want. And if you use > just the above list of tests it's likely to be more accurate than your > previous method. As the tests runs from the "boost-root/status" dir are not > alway the same as those run from the corresponding library dirs. > -- >-- Rene Rivera >>On Sat, Sep 3, 2016 at 5:09 PM, Sergey Sprogis <sergey.sprogis_at_[hidden]> >> wrote: >> I use latest Boost versions to test new C++ compiler in development stage. >> >> It's important for me to know what would be "pass rate" for every library >> which Boost.org reports on its Regression Testing website. >> To calculate all those pass rates I created script which goes inside every >> library's 'test', 'example' or whatever subdirectory and launches bjam from >> there. >> It creates a separate logfile(s) for every library which I then analyze to >> calculate "pass rate". >> >> But before launching my script I need to know the whole list of dirs which >> Boost.org uses for its Regression testing. >> In the previous Boost-1.61.0 version I was able to easily produce such >> list by extracting it from 'status/Jamfile.v2'. It looked like this: >> >> run-tests libs : >> accumulators/test # test-suite accumulators >> algorithm/test # test-suite algorithm >> algorithm/minmax/test # test-suite algorith/minmax >> ... >> concept_check # test-suite concept_check >> config/test # test-suite config >> container/bench # test-suite container benchmarks >> container/example # test-suite container_example >> ..... >> >> As you may see this list contains not only 'test' subdirs, but also some >> others: 'example', 'bench', etc. >> But now the problem is that in Boost-1.62.0 'status/Jamfile.v2' does not >> have such full list anymore. >> >> Could anyone suggest me some hack how to produce the full list of tested >> libraries for Boost-1.62.0, similar to one which Boost-1.61.0 has? >> >> It would be nice if bjam will eventually have a special option which will >> allow to produce such list, but for now I'd appreciate just a hack which >> will help me to solve this issue. >>

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Preprocessor: Expaning empty VA_ARGS
by Florian Lindner 09 Sep '16

09 Sep '16

Hello, I have this preprocessor macros: ----------- #include <boost/preprocessor/variadic/to_seq.hpp> #include <boost/preprocessor/seq/for_each_i.hpp> #include <boost/preprocessor/stringize.hpp> #include <iostream> #define TRACE(...) \ std::cout << "foo" \ BOOST_PP_SEQ_FOR_EACH_I(LOG_ARGUMENT,, BOOST_PP_VARIADIC_TO_SEQ(__VA_ARGS__)); #define LOG_ARGUMENT(r, data, i, elem) \ << std::endl << " Argument " << i << ": " << BOOST_PP_STRINGIZE(elem) << " == " << elem int main(int argc, char *argv[]) { TRACE(); return 0; } ----------- They compile when TRACE has arguments, but not without. Problem is, that LOG_ARGUMENT is called even when no args are supplied, leading to the expansion: std::cout << "foo" << std::endl << " Argument " << 0 << ": " << "" << " == " << ;; elem is empty, therefore there is no expression after the last << expected primary-expression before »;« token How can I deal with that? Thanks, Florian

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[MultIndex] Iterator/Range validity when modify entries.
by Deniz Bahadir 09 Sep '16

09 Sep '16

Hi guys, While trying to implementing a new feature, I came across a question concerning iterator/range validity of boost::multi_index. To understand the question, here is my setup: <code> // Database entry. struct Entry { int key1; int key2; }; // Access-keys. struct Index1{}; struct Index2{}; using namespace boost::multi_index; using namespace boost; // The multi_index database. using Database = multi_index_container< Entry, indexed_by< hashed_non_unique< tag<Index1>, member<Entry, int, &Entry::key1> >, hashed_non_unique< tag<Index2>, member<Entry, int, &Entry::key2> > > >; Database db; /* ... Here db is getting filled. ... */ </code> I obtain a range of entries from that database with the same value for key1 through the first index and want to modify each single entry of that range. However, I will only modify key2 (which is only used as key in the other index)! My main question is now: Does modifying an entry invalidate my range although I do not modify the member that was used as key for obtaining the range? The code in question would possibly look like this: <code> auto& index1 = db.get<Index1>(); auto range = index1.equal_range(42); for (auto it = range.first; it != range.second; ++it) { index1.modify(it, [](Entry& entry) { entry.key2 = 123; // <---- Does this invalidate my range? // entry.key1 is not getting modified! }); } </code> My follow-up question is then: If the range is indeed invalidated, what would be a working solution for that problem? Incrementing the loop-iterator by hand before modifying the entry (and not letting the loop do it)? So, would the following be a valid solution? <code> auto& index1 = db.get<Index1>(); auto range = index1.equal_range(42); if (range.first != range.second) { auto it = range.first; auto end = --range.second; do { index1.modify(it++, [](Entry& entry) { entry.key2 = 123; // <---- Does this invalidate my range? // entry.key1 is not getting modified! }); while (it != end); } </code> Of course, neither do I want to iterate over an entry twice (and thereby modify it twice) nor do I want miss an entry. And one last question: Does this problem or its solution apply to all index-types or just to hashed indexes? Thanks for the clarification. Deniz PS: Oh and by the way: Boost.MultiIndex is a really cool library. :-)

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[range] const-only UDT works as std algos, but not with boost range.
by John 08 Sep '16

08 Sep '16

A class that exposes a const_iterator, but does not expose a mutable iterator, works with std:: algorithms and range-for() loop, but does not work with boost range. // This works with std algorithms and range-for, but not with boost range. class C { public: typedef blah const_iterator; const_iterator begin() const; const_iterator end() const; }; const C c; for (auto x : c) { } // OK std::for_each(std::begin(c), std::end(c), fn); // OK boost::for_each (c, fn); // ERROR: fails SinglePassRange concept (GCC-6.2) The workaround is to add a non-const iterator type that is the same as the const iterator, and to add two additional non-const begin/end methods. class D { public: typedef blah const_iterator; const_iterator begin() const; const_iterator end() const; // kludge to make it work with boost. typedef const_iterator iterator; iterator begin(); iterator end(); }; const D d; boost::for_each (d, fn); // OK Is there a simpler solution?

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[Boost.Asio] Suggestion to improve the docs
by dariomt＠gmail.com 07 Sep '16

07 Sep '16

Hi, In the Boost.Asio docs (and in the standalone Asio) the io_service docs has a section "Stopping the io_service from running out of work" where it explains "if the application requires that all operations and handlers be allowed to finish normally, the work object may be explicitly destroyed" and then shows some code using an std::auto_ptr<boost::asio::io_service::work> which will keep the work object on the heap. However, in the accepted answer to [1] the same behavior is accomplished with a, IMHO, more elegant solution: with a boost::optional<boost::asio::io_service::work>, which, if I'm correct, will keep the work object on the stack. To destroy the work object the optional is assigned to boost::none. I'd suggest improving the docs with the boost::optional case, which - does not use "ugly" (and deprecated) auto_ptr - keeps the boost::asio::io_service::work object on the stack Regards [1] http://stackoverflow.com/questions/15568100/confused-when-boostasioio-servi…

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[boost][graph] Support for C++11 on adjacency list
by Marco Craveiro 06 Sep '16

06 Sep '16

Hi boost-users, Thanks very much for a great library - Boost in general and Boost Graph in particular . I'm trying to understand the status of a fix on Boost Graph - any pointers are greatly appreciated. My basic problem is that trying to use Boost Graph in C++ 11 (or later) mode seems to break due to a bug in adjacency list. This bug has been reported in Track [1], [2] and elsewhere [3]. Up to now I have been carrying local patches to fix this issue as per tickets [4], but to the untrained eye, it appears this issue has been fixed upstream a while ago [5]. I've read the discussion regarding Boost Graph merges [6] but - apologies - It's still not clear to me where we are. Is it possible to confirm: - that the fix is in develop and will be shipped? - if so, would it be shipped with Boost 1.62 or with a later release? I read the release notes [7] but couldn't see any references to Boost Graph. Many thanks for your time. -- Marco Craveiro MD, Domain Driven Consulting about: http://about.me/marcocraveiro blog: http://mcraveiro.blogspot.co.uk twitter: https://twitter.com/MarcoCraveiro That the Ideas are themselves manifestations (of the Idea-Idea) and that the Idea-Idea is a-kind-of Manifestation-Idea—which is a-kind-of itself, so that the system is completely self-describing— would have been appreciated by Plato as an extremely practical joke [Plato]. -- Alan Key [1] #11164 Graph adjacency_list, add_vertex compile error on clang 3.6 https://svn.boost.org/trac/boost/ticket/11164 [2] #10382 1.56.0 Graph adjacency_list has compile errors on g++ 4.6.4 https://svn.boost.org/trac/boost/ticket/10382 [3] https://lists.debian.org/debian-mentors/2016/01/msg00327.html [4] https://github.com/DomainDrivenConsulting/dogen/blob/master/patches/boost_1… [5] Fix compilation with gcc 4.4 in C++11 mode https://github.com/boostorg/graph/commit/0f4ecbcd4bd13743f74745257b95fabdbd… [6] http://lists.boost.org/Archives/boost/2016/08/230533.php [7] http://www.boost.org/users/history/version_1_62_0.html

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Fwd: Boost.Range: 'Use of deleted function' GCC error when using lambdas
by Remko Tronçon 05 Sep '16

05 Sep '16

Hi, I have the following piece of code: std::vector<std::string> list1; std::vector<std::string> list2; push_back(list2, list1 | transformed([](const auto& w) { return w; }) | sliced(0, 1)); This compiles fine with CLang, but with GCC I get the error: /usr/include/boost/optional/optional.hpp:546:64: error: use of deleted function 'main(int, const char**)::<lambda(const auto:1&)>& main(int, const char**)::<lambda(const auto:1&)>::operator=(const main(int, const char**)::<lambda(const auto:1&)>&)' void assign_value ( rval_reference_type val ) { get_impl() = static_cast<rval_reference_type>(val); } ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:46:19: note: a lambda closure type has a deleted copy assignment operator | transformed([](const auto& w) { return w; }) When I replace the lambda by a regular function, the code compiles; when I don't use 'sliced' (but pipe it to e.g. 'transformed' instead), the code also compiles. Is there a way to make this code compile with a lambda? thanks! Remko PS: I'm using GCC 6.2.0 with Boost 1.61.

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using asio.hpp - boost::system::generic_category()
by Hermann Norpois 04 Sep '16

04 Sep '16

Hello, I just started with boost and it is obvious that I do not understand give my compiler (not mentioning code::blocks) the correct instructions. I installed boost_1_61_0 on Ubuntu 14.04 and followed the instruction. So I did (as root after sudo -i) in the directory of boost_1_61_0. I use g++4.9. It was the same with g++4.8. 1) ./bootstrap.sh prefix=/usr/local 2) ./b2 install So the libs are: /usr/local/lib The headers: /usr/include/boost Actually I was interested in some stuff with asio. So I started with this code from the tutorial. http://www.boost.org/doc/libs/1_61_0/doc/html/boost_asio/tutorial/tutdaytim… g++ -Wall main.cpp -o zclient /tmp/ccxx7PrW.o: In Funktion `__static_initialization_and_destruction_0(int, int)': main.cpp:(.text+0x52e): Nicht definierter Verweis auf `boost::system::generic_category()' main.cpp:(.text+0x53a): Nicht definierter Verweis auf `boost::system::generic_category()' main.cpp:(.text+0x546): Nicht definierter Verweis auf `boost::system::system_category()' /tmp/ccxx7PrW.o: In Funktion `boost::system::error_code::error_code()': main.cpp:(.text._ZN5boost6system10error_codeC2Ev[_ZN5boost6system10error_codeC5Ev]+0x17): Nicht definierter Verweis auf `boost::system::system_category()' /tmp/ccxx7PrW.o: In Funktion `boost::asio::error::get_system_category()': main.cpp:(.text._ZN5boost4asio5error19get_system_categoryEv[_ZN5boost4asio5error19get_system_categoryEv]+0x5): Nicht definierter Verweis auf `boost::system::system_category()' /tmp/ccxx7PrW.o: In Funktion `boost::asio::detail::posix_thread::~posix_thread()': main.cpp:(.text._ZN5boost4asio6detail12posix_threadD2Ev[_ZN5boost4asio6detail12posix_threadD5Ev]+0x26): Nicht definierter Verweis auf `pthread_detach' /tmp/ccxx7PrW.o: In Funktion `boost::asio::detail::posix_thread::join()': main.cpp:(.text._ZN5boost4asio6detail12posix_thread4joinEv[_ZN5boost4asio6detail12posix_thread4joinEv]+0x2b): Nicht definierter Verweis auf `pthread_join' /tmp/ccxx7PrW.o: In Funktion `boost::asio::detail::posix_thread::start_thread(boost::asio::detail::posix_thread::func_base*)': main.cpp:(.text._ZN5boost4asio6detail12posix_thread12start_threadEPNS2_9func_baseE[_ZN5boost4asio6detail12posix_thread12start_threadEPNS2_9func_baseE]+0x29): Nicht definierter Verweis auf `pthread_create' collect2: error: ld returned 1 exit status I have to add that the simple programm in the starting guide worked properly http://www.boost.org/doc/libs/1_61_0/more/getting_started/unix-variants.htm… via g++ -Wall main.cpp -o zu It worked in Code::Blocks as well (without any additional information). Even the second simple programm (same link) I managed to compile giving the full path: g++ -Wall main.cpp -o extractmail /usr/local/lib/libboost_regex.a At no time I had not to instruct the compiler about the headers. I was wondering. So it must have anything to do with the libs. Coming back to my asio- example. Do I need libs for it? I guess is has something to do with the expression -lboost_system. I used it without understanding it. But it did not help. Actually I would appreciate if was able to use Code::Blocks but I did not manage to give Code::Blocks the correct instructions. I found some hints, at least amounts of hints ... But it did not work at all. If somebody is able to explain it (for idiots) ... This would be great. Thanks Hermann

2 1

passing variables into thread
by Alexander Carôt 03 Sep '16

03 Sep '16

Hello all, I have a thrad function like: void sj::eventTrigger(){ boost::mutex::scoped_lock lock(eventTriggerMutex); while (eventTriggerActive){ dFC->eventTriggerLock.wait(lock); /// do something with pointer-variable } } This function is executed by a eventTriggerLock.notify_all() – call from other objects and when I need to pass certain variables into the thread I have been unsing a global pointer variable. Now my question: I wonder if there is a way to get rid of the pointer variable and directly pass variables into the thread such as: eventTriggerLock.notify_all(data1) void sj::eventTrigger(int data1){ boost::mutex::scoped_lock lock(eventTriggerMutex); while (eventTriggerActive){ dFC->eventTriggerLock.wait(lock); /// do something with data1 } } Any hint welcome – thanks in advance Alex

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Priority deque?
by Paolo Bolzoni 01 Sep '16

01 Sep '16

Dear list, I was wondering if there some kind of "priority queue", that is a data structure akin the priority queue, but where you can top and pop from both sides. My use case is that I need to quickly access the maximum, but also not push new elements if they are smaller than the minimum. I am aware I can use a std::set, but in the current implementation where I always push new elements even if they are bad, using a std::set the performance is significantly worse. Yours faithfully, Paolo

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iostreams: ceased devolopment?
by Christian Meesters 01 Sep '16

01 Sep '16

Hi, I noticed that there are numerous issues in the bug list, regarding boost iostreams. However, the current doc states Copyright 2004-2007 and Tickets do not receive responses. (I even read: "(I tried e-mailing Jonathan Turkanis directly, but the e-mail address on the website seems to be not used anymore)" in ticket 7574. So, my question is: I anyone maintaining this library? If not: I doubt that there is a good alternative, because iostreams just is convenient to use and a selling point to for boost. It would be a pitty. Best regards, Christian

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