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[boost][units] reciprocal conversion / inter unit conversion
by Matthias Wohlgemuth 02 Apr '15

02 Apr '15

Dear users, I just started to use boost::units for some simulations. However, I have some problems with unit conversions and I hope someone can help me. Let's say I have a quantity given in terms of energy in "electron volts" (eV) with the unit "energy". I defined the unit the following: BOOST_UNITS_DEFINE_BASE_UNIT_WITH_CONVERSIONS(si, electron_volts, "electron volts", "eV", PHYSICAL_CONSTANT_DVALUE(e), si::energy, 5000); namespace si { typedef make_system<electron_volts_base_unit>::type electron_volt_system; typedef unit<energy_dimension,si::electron_volt_system> electron_volt_type; BOOST_UNITS_STATIC_CONSTANT(eV,electron_volt_type); } where PHYSICAL_CONSTANT_DVALUE(e) gives me the double representation of si::constants::codata::e.value(). This works fine, for conversions like eV=>Joule etc. (By the way, is there a more straight forward way, to define non-rational scaled units, than defining a new unit sytem?) Now I want to convert eV to nanometers (wavelength) This is defined as: wavelength = c/frequency = h*c/energy (c=speed of light, h = Planck's constant) I would again define a system with the base unit of wavelength and the unit wavelength_type initialized e.g. with wavelength_nanometer. First Problem: What would be the derived dimension/unit: energy, length or a new dimension like wavelength_dimenson? If I would define it as something else than energy, I will have problems when using quantity<si::electron_volt_type>(x*si::wavelength_nanometer) or quantity<si::nanometer_type>(x*si::eV) Second problem: The relationship is reciprocal: wavelength ~ 1/energy. How do I define a proper conversion? Thanks for your help! Cheers, Matthias

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Cross compiling boost 1.55 static libs
by Pham Ngoc Hai 01 Apr '15

01 Apr '15

Hi guys, I'm trying to cross compile boost for armhf but some of the functions seem to be missed.I'm using croos-tool ng, gcc-4.8 =================================For example in file system, boost::filesystem::detail::status is not there: nm stage/lib/linux_armv7/libboost_filesystem.a | grep status [returns nothing] ================================= I take a look on an existing ubuntu.14.04 armhf nm libboost_filesystem.a | grep status 00000048 t _ZN12_GLOBAL__N_113dir_itr_firstERPvS1_PKcRSsRN5boost10filesystem11file_statusES8_.isra.29.constprop.49 00001cf4 T _ZN5boost10filesystem6detail14symlink_statusERKNS0_4pathEPNS_6system10error_codeE 000019c0 T _ZN5boost10filesystem6detail6statusERKNS0_4pathEPNS_6system10error_codeE 00001b54 T _ZNK5boost10filesystem15directory_entry12m_get_statusEPNS_6system10error_codeE 00001e98 T _ZNK5boost10filesystem15directory_entry20m_get_symlink_statusEPNS_6system10error_codeE ================================= my project-config.jam: # Boost.Build Configuration # Automatically generated by bootstrap.sh import option ; import feature ; # Compiler configuration. This definition will be used unless # you already have defined some toolsets in your user-config.jam # file. #if ! gcc in [ feature.values <toolset> ] #{ using gcc : armhf : arm-unknown-linux-gnueabi-g++ : <compileflags>-fexpensive-optimizations <compileflags>-O3 <compileflags>-march=armv7-a <compileflags>-mtune=cortex-a9 <compileflags>-mfpu=neon <compileflags>-mfloat-abi=hard <compileflags>-ftree-vectorize <compileflags>-ffast-math <compileflags>-funsafe-math-optimizations <compileflags>-pipe <compileflags>-fwhole-program <compileflags>-fpermissive <compileflags>-fPIC ; #} project : default-build <toolset>gcc ; # Python configuration using python : 2.7 : ; # List of --with-<library> and --without-<library> # options. If left empty, all libraries will be built. # Options specified on the command line completely # override this variable. libraries = ; # These settings are equivivalent to corresponding command-line # options. option.set prefix : /usr/local ; option.set exec-prefix : /usr/local ; option.set libdir : /usr/local/lib ; option.set includedir : /usr/local/include ; # Stop on first error option.set keep-going : false ; ================================= I use this patch to fix the zlib problem in boost_1.55 cat no_zlib.diff Index: libs/iostreams/build/Jamfile.v2 --- libs/iostreams/build/Jamfile.v2 (revision 6521) +++ libs/iostreams/build/Jamfile.v2 (working copy) @@ -159,8 +159,6 @@ : $(sources) : <link>shared:<define>BOOST_IOSTREAMS_DYN_LINK=1 <define>BOOST_IOSTREAMS_USE_DEPRECATED - [ ac.check-library /zlib//zlib : <library>/zlib//zlib - <source>zlib.cpp <source>gzip.cpp ] : : <link>shared:<define>BOOST_IOSTREAMS_DYN_LINK=1 ; ================================= my b2 command: ./b2 link=static threading=multi --tool-set=gcc-armhf --without-python -sNO_COMPRESSION=1

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[Graph] Reserving graph memory (again)
by Sensei 01 Apr '15

01 Apr '15

Dear all, Reading all the documentation online about memory reservation in a graph, I am still wondering if it would be possible to reserve memory in advance. With a vecS container it would be quite an advantage to reserve memory, but let me be clear, I am not saying that I know the number of edges in advance, so CRS isn't an option. Until now I know of two ways to do this. The first is to add & remove an edge: add_edge(0, num_vertices(g) + list.size() - 1, g); remove_edge(0, num_vertices(g) + list.size() - 1, g); however, it won't work in my context since I could (as you see from the code) add edges to an existing graph, and I am getting weird results. I am sure this is due to my code, however, add/remove isn't really a neat solution. The second option is weird: g.m_vertices.resize(list.size() - 1); This could be used, but m_* members should, as far as I understand, be private or protected. Is there any other nice possibility? For instance, a static function in the traits that reserves memory? In case, why this cannot be done by BGL APIs? Thanks!

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[asio]
by georg＠schorsch-tech.de 31 Mar '15

31 Mar '15

Hi all, currently i try to understand boost asio a little better. Right now, i just had a very simple asio program and started 2 timers asyncronously. i expected the timer t to complete after the timer i. //-------<----------------- Current output: 10 s. 1 s. //-------<----------------- Expected output: 1 s. 10 s. //-------<----------------- Shouldn't complete the async_wait with 1 sec complete prior the 10 sec async_wait? I am on Windows 7 x64/ MSVC 2013(VS12) / Boost 1.57.0. Regards Georg //-------<----------------- #include <boost/asio.hpp> #include <boost/system/error_code.hpp> #include <iostream> void wait_handler(const boost::system::error_code &ec) { if (!ec) std::cout << "10 s." << std::endl; } void irq_handler(const boost::system::error_code &ec) { if (!ec) std::cout << "1 s." << std::endl; } int main() { boost::asio::io_service io_service; boost::asio::deadline_timer t(io_service, boost::posix_time::seconds(10)); boost::asio::deadline_timer i(io_service, boost::posix_time::seconds(1)); t.async_wait(&wait_handler); t.async_wait(&irq_handler); io_service.run(); } //-------<-----------------

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Serialization cumulatively.
by Tony Camuso 30 Mar '15

30 Mar '15

I'm trying to serialize the data from multiple passes of an app on various files. Each pass generates data that must be serialized. If I simply append each serialization, then deserialization will only occur for the first instance, since the number of records read by the deserialization will only be for the first instance. What I'm doing is deserializing on each new pass, deleting the original file, and then serializing everything again with the new information. If there were only a few files to process, this would not be a problem. However there are thousands of files. Additionally, on each new pass, I am checking to see if a certain type of record has already been saved. So, with every pass, I must look up in a deeper and deeper database. Currently, it's taking almost an hour to process about 3000 files, with an average of 55,000 lines per file. It is a huge amount of data. However, I'm looking for a way to reduce the length of time it takes to do this processing. Does anybody have a better idea than to cycle through the serialize-deserialize-lookup-serialize sequence for each file?

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gicatena
by gicatena 29 Mar '15

29 Mar '15

Wei zio!, http://dronepromocodes.com/rwyw/nbfqqnawiivmwaqogeijytr.dkroguozxdavjgpqlor… 3/29/2015 3:11:42 AM

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[gsoc15] Please help rank GSoC 2015 student projects
by Niall Douglas 27 Mar '15

27 Mar '15

Dear Boost Community, The Google Summer of Code 2015 proposals for Boost are in, and we would deeply appreciate the community's help in ranking the proposals according to merit before the 6th of April. To vote, the process is easy: 1. Go to this page https://www.google-melange.com/gsoc/homepage/google/gsoc2015 and click the "Log in" button under Mentors and Administrators. 2. Now click "Create Profile" on the same page. Note that even if you registered last year, you must register again in 2015. Fill in the form. Note that after submitting it drops you at "Edit Profile", which is confusing. 3. Click "My Dashboard", then "Connect with organisations". 4. Choose "Boost C++ Libraries". 5. In the message box, write this: "I am a member of the Boost community and the email(s) I normally post to boost mailing lists with is <email>" filling in the email address(es) you normally use to post to boost mailing lists. This lets us verify that you are indeed a long standing member of the Boost community. 6. Once we approve your request, you will get an email with the subject "Welcome as organisation member". You can now return to the Dashboard on the GSoC website where there will be a new item "Proposals". 7. Work your way through as many of the 33 proposals as you can. You can score them using the stars at the bottom of each proposal page, taking care to read any comments by the mentors and students if present. PLEASE try to rank some of the lowest scored proposals, every year we get a lot of people who only rank the top five and don't bother with the rest. Try to score on the priority basis of: (i) ability to write quality C++, using the programming competency test or samples of programming the student supplied. (ii) proposal quality and your best estimate of the student's understanding of how best to solve the problem at hand. Bear in mind a gifted programmer with a strong work ethic but poor English may appear to not understand the problem as well as native English speakers, this is why we have asked for examples of their programming competency. (iii) if the student came early to the mailing lists to ask for help writing the proposal (the mentors who helped them with their proposals have usually indicated this in the private comments). (iv) usefulness/appropriateness of the feature or work being proposed. Remember a good GSoC is more about getting promising new engineers into Boost and C++ than necessarily getting code to pass Boost peer review in a single summer. 8. Optional: If a proposal looks especially great to you and you feel able to mentor a student this year, please slide the "wish to mentor" button. Just because a proposal already has willing mentors does NOT mean you should not add yourself - if you can substitute for an existing mentor, that may mean we use that mentor for another proposal. As you know, Google Summer of Code is usually worth $42,000 - $48,000 to Boost each year, and a successful GSoC raises our visibility and reputation in the wider open source community. Our thanks to you in advance for taking the time to vote. Niall Douglas Boris Schäling --- Boost C++ Libraries Google Summer of Code 2015 admin https://svn.boost.org/trac/boost/wiki/SoC2015

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problems using boost::polygon::get_rectangles
by TomDrummond 27 Mar '15

27 Mar '15

Hello I'm trying to use the function get_rectangles to return a list of rectangles however I can' get the code to compile. code #include <boost/polygon/polygon.hpp> std::vector< boost::polygon::rectangle_data<int> > rects; typedef boost::polygon::polygon_90_with_holes_data<int> Polygon90; Polygon90 poly; typedef boost::polygon::polygon_traits<Polygon90>::point_type MyPoint; MyPoint pts[] = { boost::polygon::construct<MyPoint>(0, 0), boost::polygon::construct<MyPoint>(0, 10), boost::polygon::construct<MyPoint>(30, 10), boost::polygon::construct<MyPoint>(30, 20), boost::polygon::construct<MyPoint>(10, 20), boost::polygon::construct<MyPoint>(10, 0) }; boost::polygon::set_points(poly, pts, pts + 6); boost::polygon::get_rectangles(rects, poly ); which gives the error 1>c:\lib\boost\1.57.0\boost\polygon\detail/rectangle_formation.hpp(261): error C2784: 'boost::rational<IntType> boost::abs(const boost::rational<IntType> &)' : could not deduce template argument for 'const boost::rational<IntType> &' from 'int' 1> C:\lib\boost\1.57.0\boost/rational.hpp(104) : see declaration of 'boost::abs' 1> c:\lib\boost\1.57.0\boost\polygon\polygon_90_set_data.hpp(180) : see reference to function template instantiation 'void boost::polygon::form_rectangles<output_container,std::_Vector_iterator<std::_Vector_val<std::_Simple_types<std::pair<int,std::pair<int,int>>>>>,boost::polygon::rectangle_concept>(output_container &,iterator_type,iterator_type,boost::polygon::orientation_2d,rectangle_concept)' being compiled 1> with 1> [ 1> output_container=std::vector<boost::polygon::rectangle_data<int>,std::allocator<boost::polygon::rectangle_data<int>>> 1> , iterator_type=std::_Vector_iterator<std::_Vector_val<std::_Simple_types<std::pair<int,std::pair<int,int>>>>> 1> , rectangle_concept=boost::polygon::rectangle_concept 1> ] 1> c:\lib\boost\1.57.0\boost\polygon\polygon_90_set_concept.hpp(86) : see reference to function template instantiation 'void boost::polygon::polygon_90_set_data<int>::get_rectangles<output_container_type>(output_container &) const' being compiled 1> with 1> [ 1> output_container_type=std::vector<boost::polygon::rectangle_data<int>,std::allocator<boost::polygon::rectangle_data<int>>> 1> , output_container=std::vector<boost::polygon::rectangle_data<int>,std::allocator<boost::polygon::rectangle_data<int>>> 1> ] 1> c:\lib\boost\1.57.0\boost\polygon\polygon_90_set_concept.hpp(86) : see reference to function template instantiation 'void boost::polygon::polygon_90_set_data<int>::get_rectangles<output_container_type>(output_container &) const' being compiled 1> with 1> [ 1> output_container_type=std::vector<boost::polygon::rectangle_data<int>,std::allocator<boost::polygon::rectangle_data<int>>> 1> , output_container=std::vector<boost::polygon::rectangle_data<int>,std::allocator<boost::polygon::rectangle_data<int>>> 1> ] 1> TerrainDispatcher.cpp(185) : see reference to function template instantiation 'void boost::polygon::get_rectangles<std::vector<boost::polygon::rectangle_data<int>,std::allocator<_Ty>>,Polygon90>(output_container_type &,const polygon_set_type &)' being compiled 1> with 1> [ 1> _Ty=boost::polygon::rectangle_data<int> 1> , output_container_type=std::vector<boost::polygon::rectangle_data<int>,std::allocator<boost::polygon::rectangle_data<int>>> 1> , polygon_set_type=Polygon90 1> ] I'm quite new to both boost and templates so any help would be appreciated. -- View this message in context: http://boost.2283326.n4.nabble.com/problems-using-boost-polygon-get-rectang… Sent from the Boost - Users mailing list archive at Nabble.com.

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[geometry] Buffer multi-linestring with different distances
by Renato Silveira 26 Mar '15

26 Mar '15

Is it possible to buffer a multi-linestring where each linestring has his own distance to buffer? Something like this: http://docs.qgis.org/2.2/en/_images/variable_buffer.png Thank you in advance -- *Renato Silveira* Ph. D. Student Informatics Institute - UFRGS Porto Alegre - RS - Brazil http://www.inf.ufrgs.br/~rsilveira

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[Serialization] serialization of shared_ptr with custom deleter
by Elizabeta 26 Mar '15

26 Mar '15

Hi I am using boost 1.49. There is problem with serialization of shared_ptr with custom deleter, it doesnot preserve the deleter. After deserialization of shared_ptr with custom deleter, when using boost::get_deleter on the deserialized shared_ptr it returns null. Here is code example struct DetachTest { ~DetachTest() { int debug =0; } friend class boost::serialization::access; template<class Archive> inline void serialize(Archive & ar, const unsigned int file_version) { } }; { boost::shared_ptr<DetachTest> ss(new DetachTest,SmartDeleter<DetachTest>()); std::ofstream ofs("C:\\detach.xml"); boost::archive::xml_oarchive oa(ofs); oa & boost::serialization::make_nvp("detach",ss); } { DetachTest* test = 0; boost::shared_ptr<DetachTest> ss (test,SmartDeleter<DetachTest>()); //del is nonnul here SmartDeleter<DetachTest>* del = boost::get_deleter<SmartDeleter<DetachTest> , DetachTest>(ss); std::ifstream ifs("C:\\detach.xml"); boost::archive::xml_iarchive ia(ifs); ia & boost::serialization::make_nvp("detach",ss); //de2 is null after deserialization SmartDeleter<DetachTest>* de2 = boost::get_deleter<SmartDeleter<DetachTest> , DetachTest>(ss); } -- View this message in context: http://boost.2283326.n4.nabble.com/Serialization-serialization-of-shared-pt… Sent from the Boost - Users mailing list archive at Nabble.com.

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Cannot build libboost_mpi.so
by Patrick Begou 25 Mar '15

25 Mar '15

Hi, I'm a new user of boost library, as it is requested by fellpp that I'm trying to install. I'm compiling boost 1.57 with the basic commands: tar xvfz boost_1_57_0.tar.gz cd boost_1_57_0 ./bootstrap.sh --prefix=/share/apps/boost_1_57_0-GCC48 ./b2 But I never get the requested libboost_mpi.so ? Even if the begining of the script tells me: Component configuration: - atomic : building - chrono : building - container : building - context : building - coroutine : building - date_time : building - exception : building - filesystem : building - graph : building - graph_parallel : building - iostreams : building - locale : building - log : building - math : building - mpi : building ...... and libboost_mpi.so is requested for Fellpp.... Thanks for your advices. Patrick -- =================================================================== | Equipe M.O.S.T. | | | Patrick BEGOU | mailto:Patrick.Begou@grenoble-inp.fr | | LEGI | | | BP 53 X | Tel 04 76 82 51 35 | | 38041 GRENOBLE CEDEX | Fax 04 76 82 52 71 | ===================================================================

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Re: [Boost-users] [asio] wrap lambda async_receive call
by Cheng Mo 25 Mar '15

25 Mar '15

Hi Gravin: >The compiler will build the code for a lambda only once regardless of >how many times it's called. But it also won't let you create a >recursive lambda, which is what you would need if you wanted to have a >read operation repeat itself when it completes (which is the most common >case). I supposed that which would be built once durning compiling time but multi time in running time, wasn't it ? It will implement every time when async_xxx be invoded. Although I was not do test for proving that. >Well, actually that's not quite true -- you can type-erase a lambda via >std::function or similar and then call it recursively. But AFAIK you >can only do this when capturing by reference, and you can't safely do >that with a locally declared lambda when making async calls. So it's >not really useful in this context. Private member function or std::function type various and transmitted as reference could be better in this case. >> It's better that build a function object in static. What do you think ? >Function objects have a similar lifetime issue, and making one static is >potentially dangerous if you could have multiple operations or >connections running concurrently. It's usually simplest to use a >private method of the containing class, which is what most of the >example code does. You are right, the static is dangerous in multiple op and concurrence, Thanks. (If you really want to hide it from clients of your class, then use the PIMPL idiom.) Cheer~ 程墨 PBI―北京加维通讯电子技术有限公司地址：北京市海淀区西北旺镇丰智东路3号院邮编：100094 Mail: mcheng(a)pbicn.com

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[Boost Graph Library][Serialization] adjacency_list serialization crashes.
by Hardik Soni 23 Mar '15

23 Mar '15

Hi All, I am facing a core dump while serializing adjacency_list class object of BGL. I am using <boost/graph/adj_list_serialize.hpp> file for serialization. Following is the stack trace. I have highlighted the types used for boost::adjacency_list on frame number 19. I am using bundled property method to assign property to nodes and vertices. I tried with no_poperty, the outcome was the same. Does anyone have any idea, why is it crashing? The exception name is "output stream error". #0 0x0000003908e359e9 in raise () from /lib64/libc.so.6 #1 0x0000003908e370f8 in abort () from /lib64/libc.so.6 #2 0x000000390d660565 in __gnu_cxx::__verbose_terminate_handler() () from /lib64/libstdc++.so.6 #3 0x000000390d65e6c6 in ?? () from /lib64/libstdc++.so.6 #4 0x000000390d65e6f3 in std::terminate() () from /lib64/libstdc++.so.6 #5 0x000000390d65e91f in __cxa_throw () from /lib64/libstdc++.so.6 #6 0x000000000040de72 in boost::serialization::throw_exception<boost::archive::archive_exception> (e=...) at /usr/local/include/boost/serialization/throw_exception.hpp:36 #7 0x000000000040dce7 in boost::archive::basic_text_oprimitive<std::ostream>::save_impl<int> (this=0x7fffffffd5b0, t=@0x7fffffffd188: 6) at /usr/local/include/boost/archive/basic_text_oprimitive.hpp:122 #8 0x000000000040dc24 in boost::archive::basic_text_oprimitive<std::ostream>::save<int> (this=0x7fffffffd5b0, t=@0x7fffffffd188: 6) at /usr/local/include/boost/archive/basic_text_oprimitive.hpp:176 #9 0x000000000040db91 in boost::archive::xml_oarchive_impl<boost::archive::xml_oarchive>::save<int> (this=0x7fffffffd580, t=@0x7fffffffd188: 6) at /usr/local/include/boost/archive/xml_oarchive.hpp:75 #10 0x000000000040daeb in boost::archive::save_access::save_primitive<boost::archive::xml_oarchive, int> (ar=..., t=@0x7fffffffd188: 6) at /usr/local/include/boost/archive/detail/oserializer.hpp:88 #11 0x000000000040d9d1 in boost::archive::detail::save_non_pointer_type<boost::archive::xml_oarchive>::save_primitive::invoke<int> (ar=..., t=@0x7fffffffd188: 6) at /usr/local/include/boost/archive/detail/oserializer.hpp:232 #12 0x000000000040d595 in boost::archive::detail::save_non_pointer_type<boost::archive::xml_oarchive>::invoke<int> (ar=..., t=@0x7fffffffd188: 6) at /usr/local/include/boost/archive/detail/oserializer.hpp:308 #13 0x000000000040cccb in boost::archive::save<boost::archive::xml_oarchive, int const> (ar=..., t=@0x7fffffffd188: 6) at /usr/local/include/boost/archive/detail/oserializer.hpp:525 #14 0x000000000040c678 in boost::archive::detail::common_oarchive<boost::archive::xml_oarchive>::save_override<int const> (this=0x7fffffffd580, t=@0x7fffffffd188: 6) at /usr/local/include/boost/archive/detail/common_oarchive.hpp:69 #15 0x000000000040be67 in boost::archive::basic_xml_oarchive<boost::archive::xml_oarchive>::save_override<int> (this=0x7fffffffd580, t=...) at /usr/local/include/boost/archive/basic_xml_oarchive.hpp:112 #16 0x000000000040b5bc in boost::archive::detail::interface_oarchive<boost::archive::xml_oarchive>::operator<< <boost::serialization::nvp<int> const> (this=0x7fffffffd580, t=...) at /usr/local/include/boost/archive/detail/interface_oarchive.hpp:63 #17 0x000000000040b021 in boost::serialization::save<boost::archive::xml_oarchive, boost::vecS, boost::vecS, boost::directedS, std::string, std::string, std::string, boost::listS> (ar=..., graph=...) at /usr/local/include/boost/graph/adj_list_serialize.hpp:48 #18 0x000000000040aa65 in boost::serialization::free_saver<boost::archive::xml_oarchive, boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, std::string, std::string, std::string, boost::listS> >::invoke (ar=..., t=..., file_version=0) at /usr/local/include/boost/serialization/split_free.hpp:45 #19 0x000000000040a6e2 in boost::serialization::split_free<boost::archive::xml_oarchive, boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, std::string, std::string, std::string, boost::listS > > (ar=..., t=..., file_version=0) at /usr/local/include/boost/serialization/split_free.hpp:74 #20 0x000000000040a2cf in boost::serialization::serialize<boost::archive::xml_oarchive, boost::vecS, boost::vecS, boost::directedS, std::string, std::string, std::string, boost::listS> (ar=..., graph=..., file_version=0) at /usr/local/include/boost/graph/adj_list_serialize.hpp:109 Thanks, Hardik Soni

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try_numeric_convert (akin to try_lexical_convert)
by Chris Franz 23 Mar '15

23 Mar '15

We're using the new try_lexical_convert function in our code so we can encapsulate errors in the standard manner used in our project. A counterpart for numeric_cast would be useful. Is any such thing in the works?

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Re: [Boost-users] [range] functor defined result_type with no &, causing temporary variable warnings on VS
by Nick Stokes 23 Mar '15

23 Mar '15

This question is a followup from a multi_index discussion at http://lists.boost.org/boost-users/2015/03/84028.php. Joaquin explained the situation very accurately, so I am including his explanation following my summary below for context (I hope this does not constitute top posting :) In summary the problem is: struct Foo { int i; } struct GetIntMem { typedef int result_type; const int& operator()(const Foo& f) const { return f.i ; } }; aFooRange | boost::adaptors::transformed( GetIntMem() ); yields "warning C4172: returning address of local variable or temporary" in VS 2012 and 2013, with Boost 1.49. There is no warning with Boost 1.56. Is this construct safe with Boost 1.49? In the context of multi_index, the key extractor type is the "GetIntMem". Please see below for details. On Fri, Mar 20, 2015 at 5:33 AM, Joaquin M Lopez Munoz <joaquin(a)tid.es> wrote: > > Please don't top-post: > > http://www.boost.org/community/policy.html#quoting > > Sure. Sorry. Thanks for the link, useful info. > So, to sum up the top-posted chain of posts of yours, > boost::multi_index::member<Class,Type,PtrToMember> publicizes its > result type as > > typedef Type result_type; > > yet its call operator overloads return Type& or const Ttype&, and this > results in some warnings in VS 12 / Boost 1.49 when used in combination > with boost::adaptors::transform. > > So, whatever the problem is, it does not belong in Boost.MultiIndex, > since member merely defines result_type in accordance with the > requirements of the Key Extractor model: > > http://www.boost.org/libs/multi_index/doc/reference/ > key_extraction.html#key_extractors > > I mean, defining result_type in whatever way (or not defining it > at all) is not an error per se; it is Boost.Range assumptions on > this typedef that might be problematic. Unfortunately, the documentation > for boost::adaptors::tranform(rng,fun) > > http://www.boost.org/libs/range/doc/html/range/reference/ > adaptors/reference/transformed.html > > do not mention what the requirements on fun are, whether it is > mandatory that a result_type be present and how this is handled by > Boost.Range. I suggest you initiate a new discussion with [range] > in the subject line showing the problem you found. I suspect this > is related to boost:result_of > > http://www.boost.org/libs/utility/utility.htm#result_of > > which Boost.Range seems to use internally, but only the author can > tell. Also, if the problem does not show in Boost 1.56 you might be > encouraged to simply upgrade and move on. > > Thanks Joaquin. I could not describe the problem any better than what you have above, so I hope you don't mind that I re-purposed this thread. The question is possibly is rather moot at this point, as the issue does not manifest in Boost 1.56 (possibly earlier). However, it'd be interesting to understand why, and at least make sure using 1.49 this way is safe (I am stuck with that version for the time being). Thanks very much if you followed along this far, and sorry as I fear this post ended up more convoluted that it needs to be :P Nick

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Re: [Boost-users] [asio] wrap lambda async_receive call
by Cheng Mo 23 Mar '15

23 Mar '15

Hi Gavin: >Having said this, using lambdas can get tricky in real-world code, as >it's common to want to start the same read operation when the first >completes, and so on. Just like you said, will the code build a lambda expression when async_read() invoked ? So that "[=](const error_code& ec, size_t count" will be built servial times, it is kind of lavish for contructing the lambda expression, isn't ? It's better that build a function object in static. What do you think ? Cheers~ Cheer~ 程墨 PBI―北京加维通讯电子技术有限公司地址：北京市海淀区西北旺镇丰智东路3号院邮编：100094 Mail: mcheng(a)pbicn.com

2 1

New Iterator Concepts deprecated?
by Peter Johansson 22 Mar '15

22 Mar '15

Hi boosters, I've been looking into the New Iterator Concepts http://www.boost.org/doc/libs/1_57_0/libs/iterator/doc/new-iter-concepts.ht… and then I found this comment on boost trac https://svn.boost.org/trac/boost/ticket/1296 where dave seven years ago wrote: "/the new categories are a dead-end as the standard has lifted the reference requirement on forward iterators, so I don't plan to implement anything like this. I actually plan to deprecate the new categories./" This was seven years ago and I can't see anything about that the concepts have been deprecated, so I just wonder if this statement still holds or did the standard take back the reference requirement? Cheers, -- Peter Johansson

3 2

Boost.Locale Examples doesn't runs in VS2010
by Sarvagya Pant 22 Mar '15

22 Mar '15

I have been trying to learn Boost.Locale Module. Consider http://www.boost.org/doc/libs/1_55_0/libs/locale/doc/html/conversions_8cpp-… example. The code gets successfully compiled but when I try to run it, it gives the error Unhandled exception at 0x74d34b32 in LearningCPP.exe: Microsoft C++ exception: std::bad_cast at memory location 0x00a6fa48.. I have attached the stack-trace of the program also. Here it is: KernelBase.dll!74d34b32() [Frames below may be incorrect and/or missing, no symbols loaded for KernelBase.dll] KernelBase.dll!74d34b32() > msvcr100d.dll!_nh_malloc_dbg(unsigned int nSize, int nhFlag, int nBlockUse, const char * szFileName, int nLine) Line 302 + 0x1d bytes C++ msvcr100d.dll!malloc(unsigned int nSize) Line 56 + 0x15 bytes C++ LearningCPP.exe!std::use_facet<boost::locale::converter<char> >(const std::locale & _Loc) Line 526 C++ LearningCPP.exe!boost::locale::to_upper<char>(const char * str, const std::locale & loc) Line 225 + 0x9 bytes C++ LearningCPP.exe!main() Line 170 + 0xc4 bytes C++ LearningCPP.exe!__tmainCRTStartup() Line 555 + 0x19 bytes C LearningCPP.exe!mainCRTStartup() Line 371 C kernel32.dll!75268543() ntdll.dll!776bac69() ntdll.dll!776bac3c() Did anyone faced this issue when using Boost.Locale in Visual Studio 2010? If so, how do I resolve this issue? *PS:* I have used option Use Unicode Character Set under the Character Set option of Visual Studio. I believe the libraries are correctly linked too. -- *sarvagya*

1 0

boost::property_tree::ptree with write_xml
by Uthpal Urubail 21 Mar '15

21 Mar '15

All, I am looking got the help with xml writer using property tree. My requirement is to write a user defined comment (in below example /*comment*/) in every line of XML file. Example: /*comment*/<debug> /*comment*/ <filename>debug.log</filename> /*comment*/ <modules> /*comment*/ <module>Finance</module> /*comment*/ <module>Admin</module> /*comment*/ <module>HR</module> /*comment*/ </modules> /*comment*/ <level>2</level> /*comment*/</debug> Can someone help me in solving the above? Any help on this would be highly appreciated. boost::property_tree::xml_writer_settings<std::string> w(' ', 4); write_xml(os, pt,w); Regards, UJ

3 4

phoenix 1.55 no-arg mem function fails
by MM 20 Mar '15

20 Mar '15

#include <boost/phoenix/phoenix.hpp> struct Foo { const int& bar() const { return i; } int i; }; int main() { Foo f; const int& ir = boost::phoenix::bind(&Foo::bar, f)(); } The above fails to compile. linux g++492 -std=c++11 -c 1.cpp When bar() has a single int arg for e.g., boost::phoenix::bind(&Foo::bar, f, 5)(); succeeds. The error: In file included from /usr/include/boost/phoenix/bind/bind_member_variable.hpp:13:0, from /usr/include/boost/phoenix/bind.hpp:17, from /usr/include/boost/phoenix/phoenix.hpp:17, from 1.cpp:1: /usr/include/boost/phoenix/bind/detail/member_variable.hpp: In instantiation of ‘struct boost::phoenix::detail::member_variable<const int&() const, const int& (Foo::*)() const>’: /usr/include/boost/proto/make_expr.hpp:77:16: required from ‘struct boost::proto::detail::protoify<boost::phoenix::detail::member_variable<const int&() const, const int& (Foo::*)() const>, boost::proto::domainns_::basic_default_domain>’ /usr/include/boost/proto/detail/preprocessed/make_expr_.hpp:70:9: required from ‘struct boost::proto::detail::make_expr_<boost::phoenix::detail::tag::function_eval, boost::proto::domainns_::basic_default_domain, boost::phoenix::detail::member_variable<const int&() const, const int& (Foo::*)() const>, Foo, void, void, void, void, void, void, void, void, void>’ /usr/include/boost/proto/make_expr.hpp:185:13: required from ‘struct boost::proto::result_of::make_expr<boost::phoenix::detail::tag::function_eval, boost::proto::domainns_::basic_default_domain, boost::phoenix::detail::member_variable<const int&() const, const int& (Foo::*)() const>, Foo, void, void, void, void, void, void, void, void, void>’ /usr/include/boost/phoenix/core/preprocessed/expression_10.hpp:84:13: required from ‘struct boost::phoenix::expr_ext<boost::phoenix::actor, boost::phoenix::detail::tag::function_eval, boost::phoenix::detail::member_variable<const int&() const, const int& (Foo::*)() const>, Foo, void, void, void, void, void, void, void, void, void>’ /usr/include/boost/phoenix/core/preprocessed/expression_10.hpp:24:12: required from ‘struct boost::phoenix::expr<boost::phoenix::detail::tag::function_eval, boost::phoenix::detail::member_variable<const int&() const, const int& (Foo::*)() const>, Foo, void, void, void, void, void, void, void, void, void>’ /usr/include/boost/phoenix/core/detail/preprocessed/function_eval_10.hpp:7:561: required from ‘struct boost::phoenix::detail::expression::function_eval<boost::phoenix::detail::member_variable<const int&() const, const int& (Foo::*)() const>, Foo, void, void, void, void, void, void, void, void, void>’ /usr/include/boost/phoenix/bind/bind_member_variable.hpp:37:5: required by substitution of ‘template<class RT, class ClassT> const typename boost::phoenix::detail::expression::function_eval<boost::phoenix::detail::member_variable<RT, RT ClassT::*>, ClassT>::type boost::phoenix::bind(RT ClassT::*, ClassT&) [with RT = const int&() const; ClassT = Foo]’ 1.cpp:11:52: required from here /usr/include/boost/phoenix/bind/detail/member_variable.hpp:50:17: error: forming reference to qualified function type ‘const int&() const’ RT& operator()(Class& obj) const ^ /usr/include/boost/phoenix/bind/detail/member_variable.hpp:59:23: error: forming reference to qualified function type ‘const int&() const’ RT const& operator()(Class const& obj) const ^ /usr/include/boost/phoenix/bind/detail/member_variable.hpp:68:17: error: forming reference to qualified function type ‘const int&() const’ RT& operator()(Class* obj) const ^ /usr/include/boost/phoenix/bind/detail/member_variable.hpp:74:23: error: forming reference to qualified function type ‘const int&() const’ RT const& operator()(Class const* obj) const Rds,

1 0

phoenix: c++11
by MM 20 Mar '15

20 Mar '15

Hello Are there plans to add emplace_back to the stl part of phoenix? MM

1 0

what happens between "fixed in development" and "available in release"?
by oswin krause 20 Mar '15

20 Mar '15

Hi, Question is in the subject. What has to happen after a fix of a bug in development stage before it enters an official release? Do not get me wrong, I like boost and all it does for the community and all the effort people put into it. And i really would like to help to speed up certain...processes, but for this i have to know what can block this step? Apparently a bug in serialisation - which totally breaks my software to the point where it can not be compiled on several linux distributions und MacOsX since release of boost 1.56 - is fixed in development even prior to 1.57 and is still not available in 1.58. And what I hear from several mails across the mailing list, this is not the only change that got stuck. And somehow i have the feeling that the new boost release cycle won't make the situation any better. As I said, do not get me wrong, but this situation becomes unbearable as these boost versions spread more and more through the ecosystem and there is really nothing on my side I can do about it, except rolling my own implementation and maintaining it, until this whole thing is faded out of all major distributions(you might already get the feeling that I am not really happy about doing that). if there is something i can do to help, I will do it. But I now know that "report bugs and investigate possible fixes and send patches" does not necessarily lead to a fast fix and i am pretty frustrated by the situation. Best, Oswin

8 17

[multi_index] iterating over keys and "extracting" key extractors
by Nick Stokes 20 Mar '15

20 Mar '15

Q1: Is there a builtin in way in MI to iterate over keys rather than elements? I.e. the iterator's value type will be that of the key, not the element. Q2: Is there a way to obtain the type of key extractors given a multi index container? (it is related to Q1, as this sort of a thing could be passed to boost::transform iterator to obtain an alternative answer for Q1) An example is in order: struct Foo { int id; sting name; }; using namespace boost::multi_index; typedef multi_index_container< Foo, indexed_by< ordered_unique< member< Foo, int, &Foo::id > >, ordered_unique< member< Foo, string, &Foo::name > > > MFoo; MFoo foos; // .. populate // Now, we want to iterate over sorted name's only, for e.g: auto beg = answer_to_Q1(foos).begin(); auto end = answer_to_Q1(foos).end(); std::copy( beg, end, ostream_iterator<string>(cout, " ") ); // Continuing the example for Q2: auto aFunctorThatExtractsFooName = answer_to_Q2<M>::type(); auto beg = make_transform_iterator( M.get<1>.cbegin(), aFunctorThatExtractsFooName ); auto end = make_transform_iterator( M.get<1>.cend(), aFunctorThatExtractsFooName ); std::copy( beg, end, ostream_iterator<string>(cout, " ") ); Thanks! Nick

2 6

From: giridhar
by giridhar 19 Mar '15

19 Mar '15

Hello boost http://thalbangla.org/business.php?broken=6zpp82zkpkd1 giridhar Sent from my iPhone

1 0

[afio][v1.30 "C++ Now edition" released]
by Niall Douglas 19 Mar '15

19 Mar '15

Dear Boost, I am very pleased to announce the v1.30 release of proposed Boost AFIO, a Boost library implementing asynchronous file input/output which has been in the review queue since 2013. This is the version of AFIO which will be overviewed in my talk at C++ Now 2015. It also demonstrates the validity of the clang AST driven BindLib standalone Boost library conversion technique which will also be overviewed at C++ Now. Source distro: https://github.com/BoostGSoC13/boost.afio/archive/v1.30_Boost_v1.57.zi p Docs and CI dashboard: https://boostgsoc13.github.io/boost.afio/ Major new features in the v1.30 release: * Performance was improved by removing the transactional memory support in the v1.2 engine which is now compile time enabled only. Throughput now reaches up to 85% of raw ASIO and average latencies were reduced by 48%, yielding a 15 microsecond average latency with +/- 0.15 microsecond at a 95% confidence interval. This should enable AFIO to handle the latest generation PCIe SSDs with their 80 microsecond latencies reasonably well. * AFIO is now capable of complete standalone usage no Boost dependencies whatsoever, including for its unit testing via a Boost.Test emulation. * Due to its use of libclang AST generated template aliasing to allow user swapping of STL 11 implementation, minimum compilers required are now VS2013, GCC 4.7 and clang 3.2. All the VS2010 workarounds baggage has been eradicated. * All things related to async_data_op_req are now fully metaprogrammed with automatic generation by the compiler of suitable ASIO scatter-gather buffers from input types and STL containers with correct scatter-gather buffer coalescing where safe to do so. This automatic generation is user customisable via free function specialisation. * Support for relative paths from an open file descriptor was added. This lets you specify a file descriptor as a base from which a path fragment operates with the path resolution atomically performed in the kernel, and therefore the path of the base file descriptor may rapidly change safely. * AFIO is now optimally filing system race condition safe on all supported platforms, with per-API documentation of how much race safety is guaranteed per platform. A soak unit test verifies per commit that perfect race safety under severe and rapid filing system change is maintained. * A new afio::path type which very thinly wraps filesystem::path was added. The new afio specific path type makes the management of NT kernel path to Win32 path transition and conversion explicit, and therefore much harder to accidentally get wrong. A new normalise_path() function can convert a NT kernel path to a traditional Win32 path, complete with drive letter. * New platforms supported: Apple OS X and Android 5.0. * New filing system features support: All platforms: sparse file support, storage extent enumeration, extent deallocation ("hole punching"), volume metadata fetching (statfs), open file handle path discovery, hard link support, atomic relink (rename) support. Windows only: file symlinking, NT lock file performance flags (lock file performance is now not far from POSIX), workaround semantics for all the ways Windows will surprise you on the filing system such as files and directories which won't delete. AFIO now does a fair job of replicating POSIX filing system semantics on Windows (and better than Mingw/Cygwin presently). Linux: symlinks are now opened as file descriptors on kernels supporting that feature. * Doubled the size of the tutorial, with all the new material being non-toy examples. There is a particularly nifty "File locking via only atomic appending and hole punching" algorithm implementation in there, and it holds up surprisingly well compared to traditional file locks except on ZFS. Plus, it's completely portable. * Some utility routines in preparation for AFIO v1.4: a cryptographically strong random filename generator, a hugepage TLB STL allocator useful for efficient file copy buffers, a very highly optimised C++ 14 constexpr constructing arbitrary Hamming code SECDED template class (an amazing 22 cycles per byte for the 32784,32768 code), and secure to-hex and from-hex validating converters. * No shortage of bug fixes, helped hugely by additional unit testing for correct error handling. Detailed changelog can be found at https://boostgsoc13.github.io/boost.afio/doc/html/afio/release_notes.h tml. I'll tag a Boost 1.58 release on github once Boost 1.58 is out. This release took far longer than I originally intended mainly due to the extensive debugging of weird filing system races, and for six weeks now I've been working till 5am every night after my day job. I cannot tell you how glad I am to see this release out! My enormous thanks to my family who have put up with a lot for this release, and to my employer for a fairly dopey employee recently. Bed, here I come! Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

3 2

[Phoenix] Version 1.57 of Phoenix breaks when used with MSVC 2010 compiler?
by Andrew Nordquist 19 Mar '15

19 Mar '15

Hello, folks - I must be doing something wrong, but I can't figure it out. I/we have been using Boost in our 20,000+ lines of C++ code for a few years now. We started with 1.43, went smoothly to 1.53, and although it was bumpy going from MSVC 2008 to MSVC 2010, we are there now. We are now using MSVC 2010 and Boost 1.53. We use many routines, including Phoenix, Spirit, bind, tie, etc. I am attempting to migrate to Boost 1.57. Got clobbered with about 400 lines of unexpected diagnostic in the compiler. That is the attached file. In the file, the lines showing the files named "cutoffitem.cpp" and "densitydelegate.cpp" are ours, but what is between these two lines is coming from Boost. It appears that it could be a C++11 type of problem, but I'm not sure . I read about that potential problem with the [utility] [result_of] class template in the report designated n3276 and in the 1.57 [utility] documentation. I think the major concern with this issue was going to Boost 1.52. In our code, I tried a quick-fix precompiler #define, but it did not work. Got any ideas? I'm about to go back to version 1.53, at least until I upgrade to Visual Studio 2013. Thank you, /Andrew Nordquist Research Analyst Southwest Research Institute San Antonio, TX, USA

1 0

[geometry] Compile error on project_inverse_transformer.hpp
by Jeremy Murphy 19 Mar '15

19 Mar '15

Hi Geometry team, nice to meet some of you (Adam, Barend, Menalaos) at Meeting C++ last year! I started doing projection transformations for the first time recently and found some compilation errors (using gcc or clang) when I include "project_inverse_transformer.hpp". Specifically, this is the amusingly helpful output from clang 3.6: project_inverse_transformer.hpp:63:9: error: no member named 'convert' in namespace 'boost::geometry::detail'; did you mean 'concept'? and project_inverse_transformer.hpp:63:9: error: no template named 'point_to_point' in namespace 'boost::geometry::concept'; did you mean 'detail::conversion::point_to_point'? Are these just known unfinished features? Thanks, cheers. Jeremy

1 0

[asio] wrap lambda async_receive call
by Andrew Hundt 18 Mar '15

18 Mar '15

In C++11 is there an easy way to use boost::asio::io_service::strand::wrap() on a lambda function handling the return of an async_receive call? As noted in the docs (link below it looks like there has to be an implementation of asio_handler_invoke but I'm not sure how that would work for a lambda function. Looking through the C++11 examples I can't find any examples of using a strand. Any help would be greatly appreciated. http://www.boost.org/doc/libs/1_57_0/doc/html/boost_asio/overview/core/stra… Cheers! Andrew Hundt

2 1

Better late than never - command line interface to on line code generator
by Brian Wood 17 Mar '15

17 Mar '15

In 2007 there was some discussion here about on line code generation: http://lists.boost.org/Archives/boost/2007/02/116997.php One thing I said back then was: "There isn't a library to download." That's changed and now there's an archive that can be downloaded: http://webEbenezer.net/build_integration.html Martin Slater, commenting on the fact that the only way to use the code generator was through a web interface, said: "the fact that it cannot be integrated into the build process easily ... would deter many from using it" I agreed with him on that point at the time and have spent a lot of time since then developing a command line interface to make it easy to integrate on line code generation into build processes. The archive mentioned above is the result of that work. So now I would like to ask for further thoughts and feedback. How can it be improved? It has support for some Boost types and I'm open to adding support for more. Tia. -- Brian Ebenezer Enterprises - In G-d we trust. http://webEbenezer.net

1 0

Boost release 1.58.0 beta 1 is now available from SourceForge
by Marshall Clow 17 Mar '15

17 Mar '15

Boost release 1.58.0 beta 1 is now available from SourceForge See http://sourceforge.net/projects/boost/files/boost/1.58.0.beta.1/ <http://sourceforge.net/projects/boost/files/boost/1.58.0.beta.1/> This release contains three new libraries: • Endian: Types and conversion functions for correct byte ordering and more regardless of processor endianness. • Sort: includes spreadsort, a general-case hybrid radix sort that is faster than O(n*log(n)) • WinAPI: For details of what's in the release, see http://www.boost.org/users/history/version_1_58_0.html <http://www.boost.org/users/history/version_1_58_0.html>. Note that the links to files on this web page are for the final release - use the SourceForge link above to get the beta files. Please download the beta, give it a try, and report any problems you encounter. IMPORTANT NOTE: There is a bug with the build scripts; you have to specify the address-mode and architecture to b2. I used: ./b2 address-model=64 architecture=x86 (this will be fixed before the final release) Thanks, -- The Boost Release Team

3 2

Boost::MSM: Transition Priority
by georg＠schorsch-tech.de 17 Mar '15

17 Mar '15

I try to use boost::MSM to implement a simple state machine for testing purpose. There are several events which have to be processed in the right order, so i defer the other events, which are currently not allowed. I try to defer the events in the transition table, to have one place to look for it, despite having all states to look, what events they defer. I tried to change the transition rows to change their priorities, but it didnt help. If i unkomment the anonymous transition from live_got_image to live_wait_for_image, it works as expected, but i want to transition automaticly to repeatedly enter the states live_wait_for_image/live_got_image until the ev_stop_live get sent. I expect the following output: ------------------------------ entering: fsm_master entering: not_ready no transition from state 0 on event struct `anonymous namespace'::ev_stop_live leaving: not_ready starting: live_wait_for_image leaving: live_wait_for_image starting: live_got_image leaving: live_got_image entering: not_ready but actually i get the following output: ---------------------------------------- entering: fsm_master entering: not_ready no transition from state 0 on event struct `anonymous namespace'::ev_stop_live leaving: not_ready starting: live_wait_for_image leaving: live_wait_for_image starting: live_got_image leaving: live_got_image starting: live_wait_for_image I use boost 1.57.0 and MSVC-2013 (VS-12). Could anybody get me a useful hint? Georg Here is the code: #include <iostream> // back-end #include <boost/msm/back/state_machine.hpp> //front-end #include <boost/msm/front/state_machine_def.hpp> #include <boost/msm/front/functor_row.hpp> namespace msm = boost::msm; namespace mpl = boost::mpl; namespace { using namespace boost::msm::front; // events struct ev_start_stop {}; struct ev_start_live {}; struct ev_stop_live {}; struct ev_learn {}; struct ev_load {}; struct ev_got_image { int payload; }; // front end: define the FSM structure struct fsm_master_ : public msm::front::state_machine_def<fsm_master_> { typedef int activate_deferred_events; template <class Event, class FSM> void on_entry(Event const&, FSM&) { std::cout << "entering: fsm_master" << std::endl; } template <class Event, class FSM> void on_exit(Event const&, FSM&) { std::cout << "leaving: fsm_master" << std::endl; } // the fsm states which are not sub state machines struct not_ready : public msm::front::state<> { template <class Event, class FSM> void on_entry(Event const&, FSM&) { std::cout << "entering: not_ready" << std::endl; } template <class Event, class FSM> void on_exit(Event const&, FSM&) { std::cout << "leaving: not_ready" << std::endl; } }; // The list of FSM states struct live_wait_for_image : public msm::front::state<> { template <class Event, class FSM> void on_entry(Event const&, FSM&) { std::cout << "starting: live_wait_for_image" << std::endl; } template <class Event, class FSM> void on_exit(Event const&, FSM&) { std::cout << "leaving: live_wait_for_image" << std::endl; } }; struct live_got_image : public msm::front::state<> { // here we got the image and we can check, if we need to react on an external event // otherwise transit to wait_for_image and fetch the next image template <class Event, class FSM> void on_entry(Event const&, FSM&) { std::cout << "starting: live_got_image" << std::endl; } template <class Event, class FSM> void on_exit(Event const&, FSM&) { std::cout << "leaving: live_got_image" << std::endl; } }; // --------------------------------------------------- // initial state: fsm_master_ typedef not_ready initial_state; typedef fsm_master_ l; struct transition_table : mpl::vector< // Start Event Next Action Guard // +---------------------+----------------+-------------------+-------------------+----------------+ _row < not_ready, ev_start_live, live_wait_for_image >, _row < live_wait_for_image, ev_got_image, live_got_image >, Row < live_wait_for_image, ev_stop_live, none , Defer , none >, _row < live_got_image, none, live_wait_for_image >, _row < live_got_image, ev_stop_live, not_ready > // +---------------------+----------------+-------------------+-------------------+----------------+ > {}; // Replaces the default no-transition response. template <class FSM, class Event> void no_transition(Event const& e, FSM&, int state) { std::cout << "no transition from state " << state << " on event " << typeid(e).name() << std::endl; } }; // back-end: fsm_master typedef msm::back::state_machine<fsm_master_> fsm_master; } void test() { fsm_master s; s.start(); s.process_event(ev_stop_live()); // this gets no transitioned s.process_event(ev_start_live()); // this one enters live s.process_event(ev_stop_live()); // this gets defered s.process_event(ev_got_image()); // this one enters got_image and the stop live should get processed. // now we should be in not ready again, but we are still in live_wait_for_image } int main() { test(); return 0; }

2 3

Re: [Boost-users] [scope_exit] 1.57 MSVC C4003 warning
by Cheng Mo 17 Mar '15

17 Mar '15

Hi, Edward： Thanks a lot.

1 0

How to get Text Archive with CRLF after each record?
by Tony Camuso 16 Mar '15

16 Mar '15

I'm just getting one big line, no CRLF in the archive. Makes it difficult to debug. Interesting thing is that I was seeing CRLF in a previous archive I created in another app. There is no difference I can detect in the way I'm archiving in this app. Tool chain ... g++ (GCC) 4.9.2 20150212 (Red Hat 4.9.2-6) libstdc++-4.9.2-6.fc21.x86_64 libstdc++-devel-4.9.2-6.fc21.x86_64 Code... typedef std::multimap<unsigned, int> cnodemap_t; typedef cnodemap_t::value_type cnpair_t; typedef cnodemap_t::iterator cniterator_t; typedef std::multimap<unsigned, qnode> qnodemap_t; typedef qnodemap_t::value_type qnpair_t; typedef qnodemap_t::iterator qniterator_t; typedef qnodemap_t::reverse_iterator qnriterator_t; struct qnode { qnode(){} enum ctlflags flags; std::string sname; std::string stypnam; std::string sdecl; cnodemap_t parents; cnodemap_t children; template<class Archive> void serialize(Archive &ar, const unsigned int version) { if (version){;} ar & flags & sdecl & sname & parents & children; } }; class Cqnodemap { public: Cqnodemap(){} qnodemap_t qnmap; template<class Archive> void serialize(Archive &ar, const unsigned int version) { if (version){;} ar & qnmap; } }; static inline void write_cqnmap(const char *filename, Cqnodemap& cqnmap) { ofstream ofs(filename, ofstream::out | ofstream::app); if (!ofs.is_open()) { cout << "Cannot open file: " << filename << endl; exit(1); } { boost::archive::text_oarchive oa(ofs); oa << cqnmap; } ofs.close(); }

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Re: [Boost-users] [scope_exit] 1.57 MSVC C4003 warning
by Cheng Mo 16 Mar '15

16 Mar '15

Hi Filip: It is happened on VS 2010 as well. Hi Edward: Excuse me about this question postponed. I have just had this problem and have found this thread. Could you tell me what mean by "BOOST PP level" does ? Thanks. Sincerely Mo.Cheng

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Boost 1_58_0_rc1 is available for testing
by Marshall Clow 16 Mar '15

16 Mar '15

Release candidate files for 1.58.0 beta 1 are available at http://boost.cowic.de/rc/ As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. This helps ensure the candidates build OK before we push them out to SourceForge. IMPORTANT NOTE: There is a bug with the build scripts; you have to specify the address-mode and architecture to b2. I used: ./b2 address-model=64 architecture=x86 to test this. The files (and associated md5s) are: MD5 (boost_1_58_0_b1_rc1.7z) = 302c7dfc917227843d24beed33ccc99c MD5 (boost_1_58_0_b1_rc1.tar.bz2) = d7d030e85bf5534a328c108c62a7fb0e MD5 (boost_1_58_0_b1_rc1.tar.gz) = ec90cd23bdc99c5eaf88245ea94a28e0 MD5 (boost_1_58_0_b1_rc1.zip) = dc8379fb95c84fe2fca53a4b2c96da23 Thanks! -- The release managers

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[Asio] Need help making a custom service
by Kyle Edwards 16 Mar '15

16 Mar '15

Hello everyone, First off, I would like to say that I have been using Boost for the past few years, and have found it very useful. Thanks for all your hard work! Second, I have a question about making a custom service. I would like to make a service that triggers a callback when a GPIO pin changes state and triggers an interrupt (I'm using a Raspberry Pi.) I have (or can obtain) a file descriptor that can be poll()'d, select()'d, or epoll'd and which omits high-priority events (POLLPRI, EPOLLPRI, etc.). This entire use case is pretty Linux-specific, so it doesn't have to be very portable. What I would like to be able to do is something like this: // CODE STARTS HERE #include <iostream> #include <boost/asio.hpp> class gpio_interrupt { public: gpio_interrupt(boost::asio::io_service &io_service, unsigned int number) { // Asio magic goes here } template <typename Callback> void async_wait(Callback c) { // Asio magic goes here } }; static void my_callback(const boost::system::error_code &ec) { if (ec) return; std::cout << "Pin changed state" << std::endl; } int main(int argc, char **argv) { boost::asio::io_service io_service; gpio_interrupt interrupt(io_service, 21); interrupt.async_wait(my_callback); io_service.run(); return 0; } // CODE ENDS HERE I've looked a little bit at the Boost.Asio code (in particular the socket code) to get an idea of how I would do this, but there are so many different classes and inner classes that I'm not sure where to get started. Can someone help me? Thanks in advance! -- Kyle Edwards Software Developer 20 Corporate Circle | Albany, NY 12203 office 888-4BULLEX | 518.689.2023 | fax 518.689.2034 | web: www.bullex.com

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[context] Crash in case of exception from a context
by Tamas.Ruszkai＠leica-geosystems.com 16 Mar '15

16 Mar '15

I use boost::context to implement cooperative multitasking. At the moment I use boost 1.57 on Windows 7 with VisualStudio 2013. Everything works fine until I throw an exception from a context created by "boost::context::make_fcontext(.......)". I have seen someone had the same problem and it was caused by the Windows OS, that checks the exception hierarchy in the stack and if it finds that the starting point is not the one that should come from the OS then it terminates the process. It suspects some malitious code that corrupted the stack. http://www.blinnov.com/en/2013/04/11/english-boostcontext-and-seh/ This guy metioned in his blogpost, that this problem was solved in boost 1.53 ("Boost 1.53 has updated and fixed version of boost::context library that addresses exactly this problem. "), but somehow I still have the same thing in 1.57. Is there some special preprocessor flag (#define) that I have to activate to get this fix? Thanks! Tamas

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Boost forces Cygwin build to be 32-bit, even when it shouldn't
by Chris Taylor 15 Mar '15

15 Mar '15

I'm having trouble building boost under Cygwin. I've installed the 64 bit version of Cygwin and all programs are compiled as 64 bit. Yet, for some reason, the header ./boost/python/detail/wrap_python.hpp defines SIZEOF_LONG to be 4 when __CYGWIN__ is defined, which is only valid for a 32-bit system. This signals an error check in a python header, and the build fails. Why does this #define exist? Can we get rid of it? More info here: http://stackoverflow.com/questions/29004590/compiling-boost-on-cygwin-heade…

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[regex] stuck with expression syntax / exception
by Thomas 15 Mar '15

15 Mar '15

Hi, I am pretty much a complete novice to the boost::regex library, and stuck with the following snippet: std::string String = " (of 1000 elements; 67.10%)"; try { std::cout << boost::regex_match(String, boost::regex("^ (of \\d+ elements; .+%)$")) << std::endl; std::cout << boost::regex_match(String, boost::regex(" (of \\d+ elements;.+")) << std::endl; } catch(boost::regex_error const &) { std::cout << "caught boost::regex_error!"; } Two questions: First, why does the first not match? Second, why does the second throw? The idea of the regex is that the first number is an integer, and for the percentage number the formatting is unspecified but must terminate with '%'; otherwise all characters must match exactly. thanks, Thomas

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[Range] concatenate 2 vectors
by Christophe B. 14 Mar '15

14 Mar '15

Hi all, I want to construct a static const vector being the result of concatenation of two other vectors. I was thinking to use boost::push_back, but it takes a container as a lvalue reference as a 1st argument. I could develop the following piece of code template <typename Container, typename Range> Container concat(Container const &c, Range cont& r) { Container result = c; return boost::push_back(result, r); } static const std::vector<std::string> v = concat(v1, v2); But I wanted to avoid to reinvent the wheel. Currently, I am living with this kind of writing: static const auto v = [&]{ std::vector<std::string> result = v1; return boost::push_back(result, v2); }(); Does boost libraries offer a better alternative to this construct ? Christophe

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Need site-config.jam msvc example for cxxflags
by David Highley 13 Mar '15

13 Mar '15

> We are beating our head on the wall trying to get site-config.jam to add > an include path for the Windows SKD includes. We have tried many flavors > of this: > > using msvc : 12.0 : : <cxxflags>"-IC:\\Program Files (x86)\\Microsoft > SDLs\\Windows\\v7.1A\\Include" ; We found the magic and the file now looks like this. using msvc : 12.0 : : <compileflags>"-I\"C:\\Program Files (x86)\\Microsoft SDKs\\Windows\\v7.1A\\Include\"" ; > > > We need it to only be used with the 12.0 or Studio 2013 version of > Studio. >

1 0

Need site-config.jam msvc example for cxxflags
by David Highley 13 Mar '15

13 Mar '15

We are beating our head on the wall trying to get site-config.jam to add an include path for the Windows SKD includes. We have tried many flavors of this: using msvc : 12.0 : : <cxxflags>"-IC:\\Program Files (x86)\\Microsoft SDLs\\Windows\\v7.1A\\Include" ; We need it to only be used with the 12.0 or Studio 2013 version of Studio.

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Re: [Boost-users] Boost 1_58_0_rc1 is available for testing - coroutine2 missing
by Oliver Kowalke 12 Mar '15

12 Mar '15

boost.coroutine2 is missing in the archive

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Re: [Boost-users] [heap] Mix use of size_t and size_type
by Cheng Mo 12 Mar '15

12 Mar '15

>Hi, >While reading d_ary_heap.hpp from the heap library I was surprised to >see a mix of size_t and size_type variables in an index computation >(https://github.com/boostorg/heap/blob/master/include/boost/heap/d_ary_heap.…) > size_type last_child_index(size_type index) const > { > const size_t first_index = first_child_index(index); > const size_type last_index = (std::min)(first_index + D - 1, >size() - 1); > return last_index; > } >Isn't this a typo? >-- >Matthias Hi Matthias: I am not really reading d_ary_heap.hpp actually. As my experiences the size_type is used as the parameter in template programming. It's not a confirmed type and it is depended on what you transmit the value of type while you build template function. It could be "int, short, unsigned things even the customized type". It seems to be confirmed during compiling. In another hand, size_t is used "typedef", it is as a definition and will be confirmed during preprocessing. It has could be unsigned int, not always, but often. I hope it is helpful. Cheer~ 程墨 PBI―北京加维通讯电子技术有限公司地址：北京市海淀区西北旺镇丰智东路3号院邮编：100094 Mail: mcheng(a)pbicn.com

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[Filesystem] Issue about current_path() function, is it removed ?
by Cheng Mo 12 Mar '15

12 Mar '15

Hi all: I have found there have been no "current_path()" in filesystem scope, isn't ? Is there any other function instead it What if I want to get the current_path value ? current_path() Cheer~ 程墨 PBI―北京加维通讯电子技术有限公司地址：北京市海淀区西北旺镇丰智东路3号院邮编：100094 Mail: mcheng(a)pbicn.com

1 0

Re: [Boost-users] [heap] Mix use of size_t and size_type
by Cheng Mo 12 Mar '15

12 Mar '15

Hi Ben: >> It could be "int, short, unsigned things even the customized type". It >> seems to be confirmed during compiling. >> In another hand, size_t is used "typedef", it is as a definition and >> will be confirmed during preprocessing. > As a typedef, compile time, after the preprocessor. Thanks for that. I had mistake about this before. Cheer~ 程墨 PBI―北京加维通讯电子技术有限公司地址：北京市海淀区西北旺镇丰智东路3号院邮编：100094 Mail: mcheng(a)pbicn.com

1 0

Boost 1.57.0 Message Queue Remove
by SPONZA Cristiano (MM) 11 Mar '15

11 Mar '15

Hi, about this topic I would have two questions. The scenario is simple: 1 sender and 1 receiver sharing a boost message queue. Q1: If the sender removes the queue by the function remove("myQueue") how can the receiver to be aware the queue no longer exists? In my implementation the receiver uses the function timed_receive(...) and if the sender removes the queue the function returns false, since timeout is reached. The problem, in my case, is that the receiver cannot tell if the queue has been deleted or the sender is not sending messages anymore. Q2: I experience a different behavior of the receiver depending on the language, C or C++. Actually I created two receivers: recv.c and recv.cpp. The sender is written in C++. The operations sequence is the following: Sender: - creates the queue "myQueue" - writes some messages - removes the queue - terminates Receiver: - loops reading message on the queue "myQueue", applying timeout Sender: - restarts - creates the queue "myQueue" - ... When the sender terminates, the receiver keeps to try reading. The queue has been removed, so the timed_receive(...) function goes in timeout. When I restart the sender, the C++ receiver properly resumes reading the messages . With the C version, instead, the receiver is not able to resume and the receive function keeps going in timeout. Why the C++ version resumes while the C doesn't? If the sender terminates leaving the queue as it is and then restarts, the C receiver resumes properly. Unfortunately the implementation requires that if the sender has to terminate for any reason, the queue must be removed. I hope I've been clear enough. Thank you very much. ________________________________ VISITA IL NOSTRO NUOVO SITO WEB! - VISIT OUR NEW WEB SITE! www.magnetimarelli.com Confidential Notice: This message - including its attachments - may contain proprietary, confidential and/or legally protected information and is intended solely for the use of the designated addressee(s) above. If you are not the intended recipient be aware that any downloading, copying, disclosure, distribution or use of the contents of the above information is strictly prohibited. If you have received this communication by mistake, please forward the message back to the sender at the email address above, delete the message from all mailboxes and any other electronic storage medium and destroy all copies. Disclaimer Notice: Internet communications cannot be guaranteed to be safe or error-free. Therefore we do not assure that this message is complete or accurate and we do not accept liability for any errors or omissions in the contents of this message.

1 0

[Log] fork safety and core::set_logging_enabled(false)
by Алексей Филиппов 11 Mar '15

11 Mar '15

Hi, I am developing a project which executes some non-trivial code after fork and before exec. This code contains logging statements "BOOST_LOG_TRIVIAL(..)". I know that Boost.Log is not safe to use in child created by fork, but it this particular case it is fine to just disable logging in child process to make it safe. However I would prefer to keep these logging statements and disable logging somehow else, like setting some global flag. There is a boost::log::core::set_logging_enabled() function which seems to be the solution to this problem. Documentation says: "Setting this status to false allows you to completely wipe out any logging activity, including filtering and generation of attribute values." Unfortunately there is no note about fork safety. The question is: Is it safe to use it to disable logging in child process, even if application will try to execute log statements? Below is simple code sample. ---- #include <boost/log/trivial.hpp> #include <sys/wait.h> #include <unistd.h> void f(const char *const key) { BOOST_LOG_TRIVIAL(info) << "Some logic: " << key; } int main() { BOOST_LOG_TRIVIAL(info) << "Begin of app"; f("main"); const pid_t pid = fork(); if (pid < 0) _exit(127); if (pid > 0) { // parent BOOST_LOG_TRIVIAL(info) << "Child: " << pid; f("after-fork main"); } else { // child boost::log::core::get()->set_logging_enabled(false); // logging by other functions, is it safe? f("after-fork child"); _exit(0); } int stat_loc; const pid_t rpid = ::wait(&stat_loc); BOOST_LOG_TRIVIAL(info) << "End of app, reaped " << rpid; } ---- Any help would be greatly appreciated, Aleksey

1 0

Syslog Message Field
by Michael Peters 11 Mar '15

11 Mar '15

A question for those who are familiar with the Logging/Syslog functions in boost. I am currently experimenting with boost 1_57_0. Compiling with MSVC++ 12.0 I am using the example for syslog https://github.com/boostorg/log/blob/master/example/syslog/main.cpp Relevant Example Code Snippet sink->set_formatter ( expr::format("syslog.exe: %1%: %2%") % expr::attr< unsigned int >("RecordID") % expr::smessage ); // We'll have to map our custom levels to the syslog levels sinks::syslog::custom_severity_mapping< severity_levels > mapping("Severity"); mapping[normal] = sinks::syslog::info; mapping[warning] = sinks::syslog::warning; mapping[error] = sinks::syslog::critical; sink->locked_backend()->set_severity_mapper(mapping); // Set the remote address to sent syslog messages to sink->locked_backend()->set_target_address("localhost"); // Add the sink to the core logging::core::get()->add_sink(sink); // Add some attributes too logging::core::get()->add_global_attribute("RecordID", attrs::counter< unsigned int >()); // Do some logging src::severity_logger< severity_levels > lg(keywords::severity = normal); BOOST_LOG_SEV(lg, normal) << "A syslog record with normal level"; BOOST_LOG_SEV(lg, warning) << "A syslog record with warning level"; BOOST_LOG_SEV(lg, error) << "A syslog record with error level"; For some reason the Timestamp and Source machine name is being added to the start of Message field. So the syslog message field looks something like this: Mar 10 23:23:47 pluto syslog.exe: 0: A syslog record with normal level When I would expect the message field to look like this: syslog.exe: 0: A syslog record with normal level I have tested with both Kiwi Syslog and Syslog Watcher software for Windows on different PC’s running different OS’s and both behave in the same way. All other devices that log to the Syslog server correctly format the message field. Is there a hidden attribute (source machine name and timestamp) that I am not aware of that is being added to the message text? Is the Syslog server software perhaps receiving what it considers to be an incorrectly formatted message and is therefore corrupting the message field? Any suggestions / thoughts on what to check would be appreciated. Mike

1 0

[Interprocess] Using existing containers after grow()
by Malko 10 Mar '15

10 Mar '15

Hi, I am having some difficulties understanding the relationship between allocators for containers and grow(). Let's say I create a vector (whatever type) in shmem, then I unmap everything and proceed to grow the shmem from 1MB to 2MB and remap. I can now access my old vector and start adding new entries. What I am unsure about is: would this vector be able to create new entries until the whole 2MB are allocated, or would it stop at 1? I have not seen anywhere in the docs any warning about the need to construct new containers after a grow, so I assume my vector can grow up to to 2MB now. Then my question is: how does it know that now it can grow up to 2MB if the allocator I passed on construction was instantiated from a segment_manager that knew about a shmem of size 1MB? Is there somewhere in shared memory a segment_manager-like object that stores info about the shmem itself (and can I access it in my code)? Any help would be greatly appreciated, Malko

2 1