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[ASIO] Multicast Regression?
by Aaron_Wright＠selinc.com 14 May '14

14 May '14

I previously used ASIO from Boost 1.49 to send out multicast UDP messages up to 64K bytes in size without a problem. Now with ASIO from Boost 1.55 I can't seem to send out a multicast UDP message greater than 1500 bytes. I get this error: Code=1784 Category=system Message=The supplied user buffer is not valid for the requested operation I've looked at the code between Boost 1.49 and 1.55, (basic_datagram_socket.hpp, datagram_socket_services.hpp, win_iocp_socket_service_base.hpp and ipp) and very little has changed. Am I missing something that changed between the two? I'm using Windows and Microsoft Visual Studio 2010 for both 1.49 and 1.55. Hopefully someone has an idea of where to look. Thanks. --- Aaron Wright

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[Graph] Caching Dijkstra results
by Sensei 14 May '14

14 May '14

Dear all, I need to find the shortest path from a node to another, and this operation will be performed several times with different source/destination nodes. In many cases, I would need the same source, so I was thinking about caching the results from Dijkstra. Sincerely, I don't know what I should cache. My initial thought is creating a hashmap with key being the source node, and value something that allows me to easily retrieve the path. What do you think I need to cache? Does it suffices to have a map from node index (std::size_t) to the node's predecessor map? Thanks & Cheers!

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[thread] pthread/once.cpp doesn't compile for iOS
by Igor R 14 May '14

14 May '14

I'm upgrading Boost in an iOS project form 1.53 to 1.55, and getting the following error: cc1plus: error in backend: Couldn't allocate input reg for constraint 'Q'! cc1plus: error in backend: Couldn't allocate input reg for constraint 'Q'! lipo: can't figure out the architecture type of: /var/folders/j1/9fz1wymd0xs91683nq8gzwhr0000gn/T//ccBue08f.out "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/llvm-g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -pedantic -gdwarf-2 -fexceptions -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.1.sdk -pthread -arch arm -Wextra -Wno-long-long -Wno-variadic-macros -Wunused-function -arch armv7 -arch armv7s -fpermissive -pedantic -DBOOST_ALL_NO_LIB=1 -DBOOST_ATOMIC_STATIC_LINK=1 -DBOOST_SYSTEM_STATIC_LINK=1 -DBOOST_THREAD_BUILD_LIB=1 -DBOOST_THREAD_DONT_USE_CHRONO -DBOOST_THREAD_POSIX -DNDEBUG -D_LITTLE_ENDIAN -I"." -c -o "bin.v2/libs/thread/build/darwin-6.1~iphone/release/architecture-arm/link-static/macosx-version-iphone-6.1/target-os-iphone/threading-multi/pthread/once.o" "libs/thread/src/pthread/once.cpp" Is it a known issue? Is there a workaround? Thanks.

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boost::geometry::model::linestring
by alev mutlu 13 May '14

13 May '14

Hi all, I have the following code. I can correctly print the content of line_smp with boost::geometry::dsv but get strange results when I copy line_smp into a vector and then print the content of the vector. Any ideas on what I am doing wrong? bg::model::d2::point_xy p; while(rs->next()){ bg::set<0>(p, i); bg::set<1>(p, rs->getDouble("num")); i++; line +=p; } boost::geometry::simplify(line, line_smp, 0.3); std::cout<< " original: " << boost::geometry::dsv(line) << std::endl << "simplified: " <<boost::geometry::dsv(line_smp) << std::endl; std::vector<xy> v; v.clear(); std::copy(line_smp.begin(), line_smp.end(), std::back_inserter(v)); stringstream sa, ssa; for(int ia = 0; ia < v.size(); ia++){ sa << bg::get<1>(v[i]); cout << sa; sa.str(""); }

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[boost] [mpl] Hard upper limit for range_c
by Javier Dehesa 13 May '14

13 May '14

I was testing for_each and range_c and I've discovered that there's a hard limit in the range_c template. I'm attaching an example (copied from the for_each docs http://www.boost.org/doc/libs/1_55_0/libs/mpl/doc/refmanual/for-each.html) to illustrate it. This program compiles fine for me (g++ 4.9.0), but if I set NUM to a number over 890, the compilation fails. I receive an error about template instantiation depth, so I guess I could tune it in the compiler to make it work. But, anyway, why is this template recursively defined? Is it on purpose? I get that maybe range_c was intended just for small ranges, but, is it the only way it can work? Also, it only allows for statically defined range limits. Also, whenever it compiles, the bigger the number you put, the longer it takes to compile. Thanks. -- Javier Dehesa

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geomety::within not compiling for model::box
by mark meijer 13 May '14

13 May '14

Is this not supported for box type? NOT_IMPLEMENTED_FOR_THIS_TYPES Thanks for having a look, Mark typedef boost::geometry::model::d2::point_xy<int16_t, boost::geometry::cs::cartesian> FrameCoord_t; typedef boost::geometry::model::box<FrameCoord_t> FrameBox_t; FrameBox_t box1; FrameBox_t box2; boost::geometry::assign_values(box1, 10, 10, 20, 20); boost::geometry::assign_values(box2, 0, 0, 100, 100); bool is_within = boost::geometry::within(box1, box2); 15>ClCompile: 15> Main.cpp 15>G:\work\software-external\libs\Boost\boost_1_51_0\boost/geometry/strategies/within.hpp(57): error C2664: 'boost::mpl::assertion_failed' : cannot convert parameter 1 from 'boost::mpl::failed ************(__thiscall boost::geometry::strategy::within::services::default_strategy<TagContained,TagContaining,CastedTagContained,CastedTagContaining,CsTagContained,CsTagContaining,GeometryContained,GeometryContaining>::NOT_IMPLEMENTED_FOR_THIS_TYPES::* ***********)(boost::mpl::assert_::types<T1,T2>)' to 'boost::mpl::assert<false>::type' 15> with 15> [ 15> TagContained=boost::geometry::box_tag, 15> TagContaining=boost::geometry::box_tag, 15> CastedTagContained=boost::geometry::box_tag, 15> CastedTagContaining=boost::geometry::areal_tag, 15> CsTagContained=boost::geometry::cartesian_tag, 15> CsTagContaining=boost::geometry::cartesian_tag, 15> GeometryContained=Media::DetectionBox_t, 15> GeometryContaining=Media::DetectionBox_t, 15> T1=Media::DetectionBox_t, 15> T2=Media::DetectionBox_t 15> ] 15> No constructor could take the source type, or constructor overload resolution was ambiguous 15> G:\work\software-external\libs\Boost\boost_1_51_0\boost/geometry/algorithms/within.hpp(285) : see reference to class template instantiation 'boost::geometry::strategy::within::services::default_strategy<TagContained,TagContaining,CastedTagContained,CastedTagContaining,CsTagContained,CsTagContaining,GeometryContained,GeometryContaining>' being compiled 15> with 15> [ 15> TagContained=boost::geometry::box_tag, 15> TagContaining=boost::geometry::box_tag, 15> CastedTagContained=boost::geometry::box_tag, 15> CastedTagContaining=boost::geometry::areal_tag, 15> CsTagContained=boost::geometry::cartesian_tag, 15> CsTagContaining=boost::geometry::cartesian_tag, 15> GeometryContained=Media::DetectionBox_t, 15> GeometryContaining=Media::DetectionBox_t 15> ] 15> FrameProcessorVideoIq.cpp(357) : see reference to function template instantiation 'bool boost::geometry::within<Media::DetectionBox_t,Media::DetectionBox_t>(const Geometry1 &,const Geometry2 &)' being compiled 15> with 15> [ 15> Geometry1=Media::DetectionBox_t, 15> Geometry2=Media::DetectionBox_t 15> ] 15>G:\work\software-external\libs\Boost\boost_1_51_0\boost/geometry/strategies/within.hpp(57): error C2866: 'boost::geometry::strategy::within::services::default_strategy<TagContained,TagContaining,CastedTagContained,CastedTagContaining,CsTagContained,CsTagContaining,GeometryContained,GeometryContaining>::mpl_assertion_in_line_40' : a const static data member of a managed type must be initialized at the point of declaration 15> with 15> [ 15> TagContained=boost::geometry::box_tag, 15> TagContaining=boost::geometry::box_tag, 15> CastedTagContained=boost::geometry::box_tag, 15> CastedTagContaining=boost::geometry::areal_tag, 15> CsTagContained=boost::geometry::cartesian_tag, 15> CsTagContaining=boost::geometry::cartesian_tag, 15> GeometryContained=Media::DetectionBox_t, 15> GeometryContaining=Media::DetectionBox_t 15> ] 15>G:\work\software-external\libs\Boost\boost_1_51_0\boost/geometry/algorithms/within.hpp(285): error C2039: 'type' : is not a member of 'boost::geometry::strategy::within::services::default_strategy<TagContained,TagContaining,CastedTagContained,CastedTagContaining,CsTagContained,CsTagContaining,GeometryContained,GeometryContaining>' 15> with 15> [ 15> TagContained=boost::geometry::box_tag, 15> TagContaining=boost::geometry::box_tag, 15> CastedTagContained=boost::geometry::box_tag, 15> CastedTagContaining=boost::geometry::areal_tag, 15> CsTagContained=boost::geometry::cartesian_tag, 15> CsTagContaining=boost::geometry::cartesian_tag, 15> GeometryContained=Media::DetectionBox_t, 15> GeometryContaining=Media::DetectionBox_t 15> ] 15>G:\work\software-external\libs\Boost\boost_1_51_0\boost/geometry/algorithms/within.hpp(291): error C2955: 'boost::type' : use of class template requires template argument list 15> G:\work\software-external\libs\Boost\boost_1_51_0\boost/type.hpp(14) : see declaration of 'boost::type' 15> 15>Build FAILED. 15>

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DateTime library - how to count "working days"?
by qplace 13 May '14

13 May '14

I need to find a day that stands 30 working days from a specific date, ignoring holidays. Currently I am doing it like this: boost::gregorian::date lastdate; int maxdays(30); for (int i = maxdays; i != 0; --i) { // skip weekends gregorian_calendar::day_of_week_type dow = lastdate.day_of_week(); while ( (dow == Sunday ) || (dow == Saturday) ) { lastdate -= boost::gregorian::date_duration(1); dow = lastdate.day_of_week(); } lastdate -= boost::gregorian::date_duration(1); } I did not find the iterator that can do it cleaner, but may be there is one? Thanks.

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date_time output facet question
by Erik Türke 13 May '14

13 May '14

Hi all, i am trying to find out how to use date time output facet on a format like "%m-%d %T [%module:%level] %message" in a way that i get the date_time and the residual format ([%module:%level] %message). At the moment i am just getting the date and time without the rest of the format. Is there any chance to achieve that? Thanks in advance!

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date time output facet question
by Erik Türke 13 May '14

13 May '14

Hi all, i am trying to find out how to use date time output facet on a format like "%m-%d %T [%module:%level] %message" in a way that i get the date_time and the residual format ([%module:%level] %message). At the moment i am just getting the date and time without the rest of the format. Is there any chance to achieve that? Thanks in advance!

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Boost.Log - textual format with severity
by Keith Bennett 12 May '14

12 May '14

Hello! I'm new to boost log (like many others, I imagine since it's only a relatively new library). I'm trying to specify a format textually (eg, keywords::format = "blahblah", instead of using a compiled expression). The idea is that the format can be reconfigured easily either through a command line parameter or through the configuration file without needing to recompile. However, it seems that anything specifying %Severity% when using a custom severity_level enum will simply not be output at all. Take the example from libs/log/example/keywords/main.cpp Simply changing line 86 to be: logging::add_console_log(std::clog, keywords::format = "%Severity% %TimeStamp%: %_%"); will exhibit the problem I believe I am trying to resolve. My suspicion is that the core doesn't know about the custom Severity attribute because it hasn't been registered and so is unable to parse %Severity% to any formatter. In contrast, the add_file_log below that does correctly output the severity level because it uses a compiled expression and is therefore able to deduce what needs to be done (am I correct in that assumption)? I seem to be unable to add an attribute to resolve this without rolling my own attribute class. How do I add an attribute or formatter related to the Severity which was declared with BOOST_LOG_ATTRIBUTE_KEYWORD? I think it's worth noting that if I remove the template parameter to severity_logger on line 123 so that it matches thus: src::severity_logger< > slg; It then devolves into a standard int instead of an enum and the output is "correctly" seen -- as an int and not as a human-readable string. While this is okay for now, I would of course want it to be human-readable if possible. This is as it is in the example in libs/log/example/settings_file/main.cpp. Any help would be appreciated. -- This message contains confidential information and is intended only for the individual named. If you are not the named addressee you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately by e-mail if you have received this e-mail by mistake and delete this e-mail from your system. If you are not the intended recipient you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited.

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Re: [Boost-users] [RFC] Modern CORBA C++ IDL Mapping and implementation
by Felipe Magno de Almeida 12 May '14

12 May '14

Sorry if this ends up duplicate. But I've sent it to the developer's list and it came back. Hello Boosters, Where I work we are implementing an open source, modern, CORBA implementation and IDL mapping. We want it to support C++ and C++11 IDL mapping, but we also want to create another IDL mapping. This new IDL mapping is being experimentated in the following url https://github.com/expertisesolutions/mORBid/tree/concepts It still has some very problematic issues (like compilation-time of generated code) and of course it is still far from completion. But, we would like to hear suggestions about this approach. What we did was that an IDL interface is mapped to a typedef for boost::type_erasure (I found the idea quite cool for the reasons that I'll mention below) with the requirements defined in the IDL, e.g. its operations. The IDL also emits a model for this type_erasure which is the actual stub class and is called remote_reference. It also emits a proxy_reference model for the same type_erasure typedef which receives a std::reference_wrapper and proxies the calls, this is needed because type_erasure can't switch between by-reference and by-value in runtime. Why I believe this approach is better than current IDL to C++11 mapping: Because the IDL to C++11 mapping is too intrusive. You can't really use normal classes you have written for use as servants in CORBA because you have to inherit from Skeletons classes *and* you have to use the *exact* same signature as defined in the mapping. This is *way too restricted*. This is also inerent to the OO paradigm that CORBA uses. But, we can mimic the same features using type-erasure instead of directly using dynamic polymorphism. This gives a much greater freedom to users. It might be that Boost.type_erasure is not the best tool here because of compile-time and compiler memory usage, but the idea surely is. We still haven't seriously profiled boost.type_erasure yet, but we will do so as soon as possible. I think it might be very interesting to experiment with lite concepts and Boost.concept_check as well. Also, we created a EDSL for GIOP and IIOP mapping based on the boost.spirit infrastructure. We use that to treat alignment and endianness automatically and to use the same grammar for generation and parsing of IIOP messages. The message header grammar is defined like this: start = "GIOP" & octet('\1') /* GIOP major version */ & octet('\0') /* GIOP minor version */ & endianness [ octet(MessageType) /* message_type */ & raw_size(ulong_)[body] ] ; Which is compiled to IIOP parser or generator through boost.spirit infrastructure of make_terminal, make_directive and etc. This works splendid well and is really easy to use, extend, is statically checked and has great performance. Whoever feel interested, please take a look and comments are highly appreciated. Regards, -- Felipe Magno de Almeida

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boost 1.55 build / install on OSX - why are aliases used instead of symlinks?
by Colby Boles 08 May '14

08 May '14

I recently installed and built boost 1.55 on an OSX machine of mine. With my current make system for my app (qmake) I needed to specify where the lib and include directories for boost were and thought the best thing to do would be to set them to \usr\local\lib \usr\local\include where I can see in the lib case there are links to the various library modules and in the include case there is a link to the boost include directories. The problem is that the boost installation makes these links using aliases instead of symlinks, so everything appears fine browsing in the Finder, but at the command line, the compiler can't see these directories. I'm able to change the aliases to symlinks, or point to the actual boost directories (e.g. \usr\local\Cellar\boost\1.55.0_1\*) and everything works, but it seems like the intention was to have symlinks at \usr\local\lib and \usr\local\include so that one can just point to these places and be version agnostic? Thanks, Colby

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Check if a type has a member function (inhrited member functions also) with Boost TTI
by Hijok Payne 08 May '14

08 May '14

Boost TTI has very convenient macros for checking if a type has a member function. See http://www.boost.org/doc/libs/1_55_0/libs/tti/doc/html/the_type_traits_intr… If I have not missing something BOOST_TTI_HAS_MEMBER_FUNCTION returns false for inherited member functions. Is there a convenient Boost solution for doing this? There is a SO<http://stackoverflow.com/questions/1966362/sfinae-to-check-for-inherited-me…> solution based on SFINAE. But I would like to avoid that and would prefer a Boost solution, since that way I am more sure it works on more compilers and I want avoid maintaining code for each such specific behavior.

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boost tti has_member_function
by Matei David 08 May '14

08 May '14

I'm trying to use boost tti has_member_function to test if a user-specified allocator has the expected methods. However, this fails with standard allocators. #include <iostream> #include <memory> #include <boost/tti/has_member_function.hpp> BOOST_TTI_HAS_MEMBER_FUNCTION(deallocate) typedef std::allocator< int > T; int main() { std::cout << has_member_function_deallocate< void (T::*) (T::pointer, T::size_type) >::value << "\n"; } I tried gcc-4.8.2 and clang-3.4. I'm compiling with: {g++|clang++} -std=c++11 -I${BOOST}/include -Wall -Wextra -pedantic -Wno-ignored-qualifiers -g3 -O0 In both cases, I get a 0. However, using "-E" and grep-ing for "\<deallocate\>", I see this signature: void deallocate(pointer __p, size_type) Shouldn't I be getting a 1? Am I using it the wrong way? Thanks

2 3

[Asio] async_read_until is passing no error and bytes_transferred of zero to handler
by Marcano, Gabriel E 08 May '14

08 May '14

I wanted to ask on the mailing list about an issue I'm having with Boost.Asio on Windows 7 before making a bug report. System information: Windows 7 64-bit Professional running on an Intel quad-core i7 with 4 GB of RAM, using Visual Studio 2012 for C++ development. Used VS2012 compiler to compile Boost 1.55 libraries by following instructions found in the documentation online. In case it matters, here are the C++ preprocessor defines I'm using: WIN32;_DEBUG;_CRT_SECURE_NO_WARNINGS;NOMINMAX;WIN32_LEAN_AND_MEAN; _WIN32_WINNT=0x0601; The project was compiled with the default debug settings for Visual Studio 2012, meaning no optimizations. The problem: While using Boost.Asio to communicate with a serial device (an Arduino, 250000 baud, 8n1), sometimes async_read_until would pass to the handler both a bytes_transferred of zero and an error condition indicating success. According to http://www.boost.org/doc/libs/1_55_0/doc/html/boost_asio/reference/ async_read_until/overload1.html, this should never occur (if I'm interpreting the documentation correctly). Specifically, under parameters, under handler: // The number of bytes in the streambuf's get // area up to and including the delimiter. // 0 if an error occurred. The odd thing about this problem is that it is not easily reproducible... I think it may be a race condition. The files I'm attaching include the wrapper class I made to access the serial port in Windows, with a small main function at the bottom of the implementation .cpp file. I almost couldn't reproduce the error with this setup-- it took me a few dozen runs to get it to manifest itself. I can guarantee that the problem does not lie with the Arduino or the UART communication-- I have been running USBPcap to make sure that USB communication is taking place. I can see all data travelling to and from the Arduino by analyzing the USBPcap output through Wireshark. The Arduino I have has a set of ASCII serial commands it supports. The only one I use in the included code is "?\r", which makes it return "ACK\r\nArduino\r\n". Based on my searching, the closest bugs to what I'm experiencing seem to be these ones: https://svn.boost.org/trac/boost/ticket/8933 https://svn.boost.org/trac/boost/ticket/8967 I considered disabling IOCP for testing, but serial port communication depends on IOCP in Windows. The original problem is far more reliably reproduced-- using Visual Studio's unit testing framework, I am running essentially the same code included in the main function of the included code. I'd say about one of every three or two runs results in the error using the unit testing framework. Running the code in the actual application I'm developing also reliably reproduces the problem (MFC application). The attached .zip file includes the stripped down version of the project used to reproduce the problem, the stack frame of the error as caught by the assert inside readUntilComplete, and a core dump with the heap for the stripped project when the error occurred. The debugging symbols for the core dump are also included in the top-most directory of the .zip file. I would greatly appreciate any input/suggestions on the issue. If people are having trouble reproducing the problem, I seemingly can occasionally reproduce it so I can do more analysis, if someone were to point me in the right direction. Thank you for your time! Sincerely, Gabriel E. Marcano

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Re: [Boost-users] [Asio] async_read_until is passing no error and bytes_transferred of zero to handler
by Marcano, Gabriel E 07 May '14

07 May '14

> The attached .zip file includes the stripped down version of the project used > to reproduce the problem I'm unsure if my .zip file made it through the mailing list (I don't think so, as best as I can tell). For the time being, I've uploaded the .zip to my Google drive. As a heads up, it's around 15 MB compressed due to the core dump. The link is found here: https://drive.google.com/file/d/0B6KwsUWQzY0NdVhIMDFLUWpPLTg/edit?usp=shari… Let me know if there is anything other information I can provide! Sincerely, Gabriel E. Marcano

2 1

porting boost threads
by Jono Poff 07 May '14

07 May '14

Hi, this is my first post. I'm experimenting with boost 1.55.0 having last used version 1.3.mumble. I'm porting some old classes to see what changes there are and it has been quite smooth, with spirit stuff coming over easily using the classic namespace. One of my old wrapper classes typedefs boost::detail::thread::scoped_lock<boost::recursive_mutex> which seems to be missing from the latest version. Replaced with boost::mutex::scoped_lock perhaps? I expect to find other changes i thread... Can anyone point me to an explanation of changes to Boost thread that would help smooth this transition. Cheers, Jono -- ------------------------------ This email, including any attachments, is only for the intended recipient. It is subject to copyright, is confidential and may be the subject of legal or other privilege, none of which is waived or lost by reason of this transmission. If you are not an intended recipient, you may not use, disseminate, distribute or reproduce such email, any attachments, or any part thereof. If you have received a message in error, please notify the sender immediately and erase all copies of the message and any attachments. Unfortunately, we cannot warrant that the email has not been altered or corrupted during transmission nor can we guarantee that any email or any attachments are free from computer viruses or other conditions which may damage or interfere with recipient data, hardware or software. The recipient relies upon its own procedures and assumes all risk of use and of opening any attachments. ------------------------------

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[PropertyTree] read_json() followed by write_xml produces invalid XML
by Marcel Loose 07 May '14

07 May '14

Hi all, Last week I posted the message below to the Boost Users group. One of the posters suggested that I stumbled upon a bug in Boost.PropertyTree. So, the question is: am I doing something wrong, or is this is a bug in Boost.PropertyTree? Best regards, Marcel Loose. ---- Start of message ---- I was quite surprised and disappointed to find out that I was unable to convert a simple JSON file into XML, using the Boost PropertyTree. As input I used the example JSON file from the documentation (see example.json below). I wrote a small program (see example.cc below) that reads in this JSON file, writes it to disk as XML file, and finally tries to read back this XML file. This last operation fails with an exception (see output below); the XML file that is produced (see example.xml below) is invalid, because it contains empty tags (<>). Am I doing something wrong? Best regards, Marcel Loose. $ cat example.json { "menu": { "foo": true, "bar": "true", "value": 102.3E+06, "popup": [ {"value": "New", "onclick": "CreateNewDoc()"}, {"value": "Open", "onclick": "OpenDoc()"} ] } } $ cat example.cc #include <boost/property_tree/ptree.hpp> #include <boost/property_tree/json_parser.hpp> #include <boost/property_tree/xml_parser.hpp> #include <fstream> using namespace std; using namespace boost::property_tree; int main() { ptree pt; { read_json("example.json", pt); ofstream ofs("example.xml"); write_xml(ofs, pt, xml_writer_make_settings(' ', 2)); } { ifstream ifs("example.xml"); read_xml(ifs, pt); } return 0; } $ ./example terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::property_tree::xml_parser::xml_parser_error> >' what(): <unspecified file>(7): expected element name Aborted $ cat example.xml <?xml version="1.0" encoding="utf-8"?> <menu> <foo>true</foo> <bar>true</bar> <value>102.3E+06</value> <popup> <> <value>New</value> <onclick>CreateNewDoc()</onclick> </> <> <value>Open</value> <onclick>OpenDoc()</onclick> </> </popup> </menu> ---- End of message ----

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Boost PropertyTree: read_json() followed by write_xml() produces invalid XML
by Marcel Loose 07 May '14

07 May '14

Hi all, Last week I posted the message below to the Boost Users group. One of the posters suggested that I stumbled upon a bug in Boost.PropertyTree. So, the question is: am I doing something wrong, or is this is a bug in Boost.PropertyTree? Best regards, Marcel Loose. ---- Start of message ---- I was quite surprised and disappointed to find out that I was unable to convert a simple JSON file into XML, using the Boost PropertyTree. As input I used the example JSON file from the documentation (see example.json below). I wrote a small program (see example.cc below) that reads in this JSON file, writes it to disk as XML file, and finally tries to read back this XML file. This last operation fails with an exception (see output below); the XML file that is produced (see example.xml below) is invalid, because it contains empty tags (<>). Am I doing something wrong? Best regards, Marcel Loose. $ cat example.json { "menu": { "foo": true, "bar": "true", "value": 102.3E+06, "popup": [ {"value": "New", "onclick": "CreateNewDoc()"}, {"value": "Open", "onclick": "OpenDoc()"} ] } } $ cat example.cc #include <boost/property_tree/ptree.hpp> #include <boost/property_tree/json_parser.hpp> #include <boost/property_tree/xml_parser.hpp> #include <fstream> using namespace std; using namespace boost::property_tree; int main() { ptree pt; { read_json("example.json", pt); ofstream ofs("example.xml"); write_xml(ofs, pt, xml_writer_make_settings(' ', 2)); } { ifstream ifs("example.xml"); read_xml(ifs, pt); } return 0; } $ ./example terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::property_tree::xml_parser::xml_parser_error> >' what(): <unspecified file>(7): expected element name Aborted $ cat example.xml <?xml version="1.0" encoding="utf-8"?> <menu> <foo>true</foo> <bar>true</bar> <value>102.3E+06</value> <popup> <> <value>New</value> <onclick>CreateNewDoc()</onclick> </> <> <value>Open</value> <onclick>OpenDoc()</onclick> </> </popup> </menu> ---- End of message ----

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Boost pool and move constructor
by Bruno Sanches 06 May '14

06 May '14

I am trying to create a object using boost object_pool, but trying to use the move constructor of the desired object, but on Visual 2013, I am always getting: error C2664: 'MyObject::MyObject(const MyObject &)' : cannot convert argument 1 from 'MyObject (__cdecl &)(void)' to 'MyObject &&' The error happens because boost pool construct method always assume a const parameter. Sample code: #include <boost/pool/object_pool.hpp> class MyObject{ public: MyObject(): m_iData(0) { } MyObject(MyObject &&other): m_iData(std::move(other.m_iData)) { other.m_iData = 0; } MyObject(const MyObject &rhs) = delete; MyObject &operator=(const MyObject &rhs) = delete; private: int m_iData;}; int main(int, char**){ boost::object_pool<MyObject> pool; MyObject obj; MyObject *pObj = pool.construct(std::move(obj));} Is there any way to invoke the move constructor using boost::object_pool? Thanks Bruno Sanches ======================== http://www.pontov.com.br

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Sequence of boost::logic::tribools - let indeterminate entries inherit from their neighbours
by Jens Müller 06 May '14

06 May '14

Hi, I have a sequence of tribools and I want element with a indeterminate value to inherit from their neighbours. Does such an algorithm exist already in Boost? If not, do you think it would be a useful addition? BR, Jens

1 0

[range] can't use boost::any_range with RTTI disabled due to boost::polymorphic_downcast
by Adam Romanek 06 May '14

06 May '14

Hi! I'd like to draw your attention to an issue with boost::any_range that prevents it from being used with RTTI disabled. The problem is that boost::any_range indirectly uses boost::polymorphic_downcast which in turn uses dynamic_cast. Note that the dynamic_cast is only used to ensure the requested cast is valid and it's done only in non-release builds. It would be great if the check was simply skipped in RTTI-disabled environments, as it is done in release builds. This would result in loss of safety that boost::polymorphic_downcast provides but the pieces that use it would at least compile in RTTI-disabled environments. Would it be possible to fix this problem? If you wish I could create a ticket for this issue. BTW, there's a typo in the documentation of boost::any_range [1]. It mentions boost::forward_pass_traversal_tag, which does not exist. It should rather be boost::forward_traversal_tag. WBR, Adam Romanek [1] http://www.boost.org/doc/libs/1_55_0/libs/range/doc/html/range/reference/ra…

2 1

Boost support of MinGW
by Kosta Zertsekel 05 May '14

05 May '14

Hi guys, It is said that MinGW is not supported by Boost because it is not fully POSIX compatible: http://www.boost.org/doc/libs/1_55_0/more/getting_started/windows.html#pch Excerpt: "A note to Cygwin and MinGW users If you plan to use your tools from the Windows command prompt, you're in the right place. If you plan to build from the Cygwin bash shell, you're actually running on a POSIX platform and should follow the instructions for getting started on Unix variants. Other command shells, such as MinGW's MSYS, are not supported-they may or may not work." Does it mean that is some program that uses Boost was compiled with MinGW, then it can randomly crash or has some stability issues? Thanks in advace, --- Kosta

1 0

[TypeIndex 3.0] Review Manager's Report
by Niall Douglas 04 May '14

04 May '14

Dear Boost, The second round of peer review of proposed Boost.TypeIndex finished on Wed 30th, and here is the review manager's report. My thanks to the five reviewers who took the time and trouble to submit full reviews, plus to everyone else who commented. Votes regarding acceptance: 4 voted to accept TypeIndex into Boost immediately. 1 voted to accept into Boost with conditions. Overall: I recommend immediate acceptance into Boost. Conditions: 1. No one liked the present boost::typeind namespace, almost anything else would be better. I see the namespace has already changed in the develop branch to boost::typeindex, so I think this is already solved. Other common comments: * More than one reviewer mentioned how they liked the docs. * More than one reviewer expressed a desire for an ability to programmatically parse through type specifier strings. I agree with Antony that that is another library which isn't TypeIndex (something Boost.Spirit based which works directly with mangled symbol string representations, representing them as a partial AST - preferably also with a libclang compatible backend - would be great, but that is a totally different library and TypeIndex 3.x provides extensibility for such an additional function). * More than one reviewer sought some method of preventing link if you mix up incompatible uses of TypeIndex and/or with RTTI. Niall -- Currently unemployed and looking for work in Ireland. Work Portfolio: http://careers.stackoverflow.com/nialldouglas/

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What's wrong with my code?
by Bill David 04 May '14

04 May '14

Hi all, I meet a problem with some code with boost and want to ask for some help here. To the following code: #include <list> using namespace std; #include "boost/function.hpp" #include "boost/foreach.hpp" #include "boost/bind.hpp" using namespace boost; void InsertItemHelper(list<int>& inContainer, list<int>::iterator& ioPosition, const list<int>::value_type& inItem) { ioPosition = inContainer.insert(ioPosition, inItem); } void WorkerFunction(const list<int>& inContainer, boost::function<void(int)> const& inAddItemCallback) { BOOST_FOREACH(auto item, inContainer) { inAddItemCallback(item); } } void Print(const list<int>& inContainer) { BOOST_FOREACH(auto item, inContainer) { std::cout << item << endl; } } int main() { list<int> sourceContainer; sourceContainer.push_back(1); sourceContainer.push_back(2); sourceContainer.push_back(3); list<int> targetContainer; list<int>::iterator pos = targetContainer.end(); boost::function<void(int)> addItemCallbackFxn(boost::bind(& InsertItemHelper, targetContainer, pos, _1)); WorkerFunction(sourceContainer, addItemCallbackFxn); return 0; } When I run it on Windows with VS2012, I always get a “list insert iterator outside range” error with: inContainer.insert(ioPosition, inItem); It seems targetContainer I passed to boost::bind is copied so that the following debug error of STL is hit: #if _HAS_ITERATOR_DEBUGGING if (_Where._Mycont != this) _DEBUG_ERROR("list insert iterator outside range"); #endif /* _HAS_ITERATOR_DEBUGGING */ But I am passing targetContainer as a reference and after the error, I can correctly get data in it. Does anybody know what’s wrong behind? Thanks, BD

2 1

[Date Time] time_period has not default constructor
by Pablo Madoery 30 Apr '14

30 Apr '14

I am using the library Date Time, in particular the object time_period. I was wondering why (if there is a good reason) this class has not a default constructor. the default constructor result usefull when using for example a map with the operator [] or when using serialization from Boost. ptime class has default constructor. If a time_period is formed by two ptime objects, why time_period has not its default constructor as well. Thanks

1 0

allocating shared memory fails beyond 8 GB
by vipin sachdeva 30 Apr '14

30 Apr '14

Hi, I am using managed_xsi_shared_memory to allocate memory as below: boost::interprocess::managed_xsi_shared_memory shmem(boost::interprocess::create_only, key, atol(argv[2])); For some reason, I cannot allocate more than 8 GB of memory. Both sysctl and ipcs have limits higher than that set (output below). ------ Shared Memory Limits -------- max number of segments = 1874919423 max seg size (kbytes) = 9765624999999 max total shared memory (kbytes) = 39999999999999996 min seg size (bytes) = 1 kernel.shmmax = 9999999999999999 kernel.shmall = 9999999999999999 kernel.shmmni = 1874919423 vm.hugetlb_shm_group = 0 Is there any reason why this allocation should fail ?

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[typeindex v3.0] Peer review begins Mon 21st ends Wed 30th
by Niall Douglas 30 Apr '14

30 Apr '14

Dear Boost, A second round of community review begins for proposed Boost.TypeIndex on Mon 21st, lasting ten days. I should apologise as it's my fault for starting another peer review straight after Boost.Align ends, however I was busy as Google Summer of Code admin until today, and I will be preparing to talk at C++ Now straight after this review ends. I hope that this doesn't affect the community's willingness to contribute to the review. Reminder of the report from the last TypeIndex v2.1 review: https://groups.google.com/forum/#!topic/boost-list/TeiSdkRkUF0 Reminder of the original peer review announcement: http://boost.2283326.n4.nabble.com/TypeIndex-Peer-review-period-for-li brary-acceptance-begins-ending-Thurs-21st-Nov-td4654788.html Source code: https://github.com/apolukhin/type_index/zipball/master Github: https://github.com/apolukhin/type_index Documentation: http://apolukhin.github.com/type_index/index.html Changes in TypeIndex v3.0 since v2.1 (from my own review of it): 1. Documentation is hugely improved over v2.1, lots of side by side examples illustrating the differences and similarities. 2. You can now create your own custom type indices using an extensible framework. 3. boost::typeind::type_info now exports raw_name() and pretty_name() to maximise MSVC-GCC compatibility, and to solve point 1 but not point 2 in the v2.1 report. 4. The undefined behaviour trick used in v2.1 has been replaced with a cast via the placeholder type boost::typeind::detail::ctti_data which can be viewed in https://github.com/apolukhin/type_index/blob/master/include/boost/type _index/ctti_type_index.hpp. There is an explanation in the comments there about this technique's compatibility with the C++ standard. 5. TypeIndex now defines everything in the boost::typeind namespace instead of the boost namespace. So: 1. What is your evaluation of the design? 2. What is your evaluation of the implementation? 3. What is your evaluation of the documentation? 4. What is your evaluation of the potential usefulness of the library? 5. Did you try to use the library? With what compiler? Did you have any problems? 6. How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? 7. Are you knowledgeable about the problem domain? And finally, every review should answer this question: 8. Do you think the library should be accepted as a Boost library? Be sure to say this explicitly so that your other comments don't obscure your overall opinion. Thanks, Niall -- Currently unemployed and looking for work in Ireland. Work Portfolio: http://careers.stackoverflow.com/nialldouglas/

5 7

update cycle
by Philipp Kraus 30 Apr '14

30 Apr '14

Hello, I try to compile Boost myself under OSX and the thread library runs into compiler errors. I have seen that the fix is inserted into the repo, so I would like to wait to a new Boost release. The last Boost version (1.55.0) was released on November 2013, so my question is in which cycles are new releases created (half a year)? Thanks Phil

1 0

Boost::Interprocess - using variadic template args with managed_shared_memory::construct()
by james 28 Apr '14

28 Apr '14

Hi, I'm trying to write a wrapper over some of boost::interprocess and I want to have a function like this: template <typename T, typename... Args> T* Wrapper::createStruct(const std::string& name, Args&&... args) { return m_shm->construct<T>(name.c_str())(std::forward<Args>(args)...); } This fails to compile as it seems boost::interprocess uses its own varargs scheme when I try to create the following struct in the SHM through this wrapper function: struct Custom { Custom(int a, int b) : m_a(a), m_b(b) { } int a; int b; } int main() { ... Custom* c = shm->createStruct("Custom", 1, 2); } The error message: /usr/include/boost/interprocess/detail/named_proxy.hpp:79:7: error: no matching function for call to ‘test_sharedmemory::sharedmemory_custom::test_method()::Custom::Custom()’ { new((void*)mem)T(boost::forward<Args>(get<IdxPack>(args_))...); } ^ /usr/include/boost/interprocess/detail/named_proxy.hpp:79:7: note: candidates are: /home/james/dev/infinityplus/test/common/shm/sharedmemory/main.cpp:136:7: note: test_sharedmemory::sharedmemory_custom::test_method()::Custom::Custom(int, int) Custom(int one, int two) ^ /home/james/dev/infinityplus/test/common/shm/sharedmemory/main.cpp:136:7: note: candidate expects 2 arguments, 0 provided Is there any way I can get this to work? I'd rather my wrapper's interface used std only. boost 1.55 c++11 g++ 4.8.2 TIA, James

2 1

Announcing the student program for Meeting C++ 2014
by Jens Weller 28 Apr '14

28 Apr '14

Hello C++ and Boost Community, today I have the honor to announce the student program for Meeting C++ 2014: > The Meeting C++ Student program will enable 50 students to attend Meeting C++ 2014 plus 3 exclusive workshops organized by think-cell one day before the conference on December 4th. So, for students this will be a 3 day conference! After the workshops you will be invited to the student dinner by think-cell. Further details at http://meetingcpp.com/index.php/newsreader/items/meeting-cpp-2014-the-stude… kind regards, Jens Weller

1 0

[Coroutine 1.54] Compile error with bool return from coroutine-function
by Rob Desbois 27 Apr '14

27 Apr '14

(Caveat: I've been unable to find anything about this; hopefully haven't missed anything obvious.) (Apology: I'm aware Coroutine has a new interface as of 1.55; I haven't determined whether it is also affected.) Given the following code: #include <cassert> #include <boost/bind.hpp> #include <boost/coroutine/coroutine.hpp> using coro_t = boost::coroutines::coroutine< bool() >; void get_a_bool( coro_t::caller_type& yield ) { while (true) yield(true); } int main() { coro_t producer( boost::bind(&get_a_bool, _1) ); assert( producer ); } I get this error on compilation (g++ 4.8.2, Boost 1.54): rob{code 0} 839# clear && g++ boost-coroutine-bool-return.cpp -g -W -Wall --std=c++11 -L. -lboost_context -lboost_coroutine -o boost-coroutine-bool-return In file included from /usr/include/boost/coroutine/v1/detail/coroutine_base_resume.hpp:26:0, from /usr/include/boost/coroutine/v1/detail/coroutine_base.hpp:21, from /usr/include/boost/coroutine/v1/coroutine.hpp:30, from /usr/include/boost/coroutine/coroutine.hpp:13, from boost-coroutine-bool-return.cpp:11: /usr/include/boost/coroutine/detail/holder.hpp: In instantiation of ‘struct boost::coroutines::detail::holder<bool>’: /usr/include/boost/coroutine/v1/detail/coroutine_base_resume.hpp:103:28: required from ‘void boost::coroutines::detail::coroutine_base_resume<Signature, D, void, 1>::resume(boost::coroutines::detail::coroutine_base_resume<Signature, D, void, 1>::arg_type) [with Signature = void(bool); D = boost::coroutines::detail::coroutine_base<void(bool)>; boost::coroutines::detail::coroutine_base_resume<Signature, D, void, 1>::arg_type = bool]’ /usr/include/boost/coroutine/v1/detail/coroutine_op.hpp:268:9: required from ‘D& boost::coroutines::detail::coroutine_op<Signature, D, void, 1>::operator()(boost::coroutines::detail::coroutine_op<Signature, D, void, 1>::arg_type) [with Signature = void(bool); D = boost::coroutines::coroutine<void(bool), 1>; boost::coroutines::detail::coroutine_op<Signature, D, void, 1>::arg_type = bool]’ boost-coroutine-bool-return.cpp:29:13: required from here /usr/include/boost/coroutine/detail/holder.hpp:39:14: error: ‘boost::coroutines::detail::holder<Data>::holder(boost::coroutines::detail::coroutine_context*, bool) [with Data = bool]’ cannot be overloaded explicit holder( coroutine_context * ctx_, bool force_unwind_) : ^ /usr/include/boost/coroutine/detail/holder.hpp:35:14: error: with ‘boost::coroutines::detail::holder<Data>::holder(boost::coroutines::detail::coroutine_context*, Data) [with Data = bool]’ explicit holder( coroutine_context * ctx_, Data data_) : At a glance it looks like there's no way a coroutine-function could possibly return bool due to the overload collision. Is this right? Did I miss something completely obvious in the docs? It's easy enough to work around with a transparent bool wrapper, I just want to be sure I'm not being a muppet :-D TIA -- rob -- Rob Desbois http://theotherbranch.wordpress.com/

2 1

Boost PropertyTree: read_json() followed by write_xml produces invalid XML
by Marcel Loose 27 Apr '14

27 Apr '14

Hi all, I was quite surprised and disappointed to find out that I was unable to convert a simple JSON file into XML, using the Boost PropertyTree. As input I used the example JSON file from the documentation (see example.json below). I wrote a small program (see example.cc below) that reads in this JSON file, writes it to disk as XML file, and finally tries to read back this XML file. This last operation fails with an exception (see output below); the XML file that is produced (see example.xml below) is invalid, because it contains empty tags (<>). Am I doing something wrong? Best regards, Marcel Loose. $ cat example.json { "menu": { "foo": true, "bar": "true", "value": 102.3E+06, "popup": [ {"value": "New", "onclick": "CreateNewDoc()"}, {"value": "Open", "onclick": "OpenDoc()"} ] } } $ cat example.cc #include <boost/property_tree/ptree.hpp> #include <boost/property_tree/json_parser.hpp> #include <boost/property_tree/xml_parser.hpp> #include <fstream> using namespace std; using namespace boost::property_tree; int main() { ptree pt; { read_json("example.json", pt); ofstream ofs("example.xml"); write_xml(ofs, pt, xml_writer_make_settings(' ', 2)); } { ifstream ifs("example.xml"); read_xml(ifs, pt); } return 0; } $ ./example terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::property_tree::xml_parser::xml_parser_error> >' what(): <unspecified file>(7): expected element name Aborted $ cat example.xml <?xml version="1.0" encoding="utf-8"?> <menu> <foo>true</foo> <bar>true</bar> <value>102.3E+06</value> <popup> <> <value>New</value> <onclick>CreateNewDoc()</onclick> </> <> <value>Open</value> <onclick>OpenDoc()</onclick> </> </popup> </menu>

3 3

Library advice
by Mathew Benson 27 Apr '14

27 Apr '14

Is there a boost library that I can use to dynamically deserialize structures from untyped buffers? I need to write code that receives a buffer of data from another computer, with some data serialized with bitfield structs. Yes, I do understand the difficulty of doing this and that it would have been easier if the data was serialized properly before transmission. I have no control over the transmitted data, but I can get the data format defined accurately. I fully understand the numerous edge cases and pitfalls with doing this and don't take the task lightly. Therefore, I'm looking for libs and open source code to make it easier. The incoming data format can and frequently does change so I can't hard code the format, but the format is defined in an XML file. I wrote an internal database containing field type, offset, and bit lengths, and populated via the XML file. My XML file is auto generated to match the as built interface definition, bit for bit. I wrote code that deserializes most of the data, but I need to rewrite it as a general purpose function to work for all cases, including bitfield structs. For now, I can assume same CPU (little endian) and the same compiler (gcc). However, both source and destination CPUs and OS's might be 32 bit or 64 bit. In future versions, I would like to add support for endian conversion and differing compiler packing. Does boost have something that would help? Sent from my Packard Bell 386

3 3

[Range] Extending the library for a base class and all its derived - enable_if
by Albert Yiamakis 26 Apr '14

26 Apr '14

Hello, I am looking to make a class, whose definition I cannot touch, model a Range concept. To that end I use method 2, http://www.boost.org/doc/libs/1_55_0/libs/range/doc/html/range/reference/ex… However, I am unable to specialize the relevant metafunctions (range_const_iterator, range_mutable_iterator, range_iterator) since they do not have an additional template parameter that would permit me to employ enable_if. I have found this impossible without touching either the class' definition or the metafunctions. Perhaps there is some other trick I am not aware of, in which case I would greatly appreciate hearing about it. If such a trick does not exist, then should these metafunctions feature an additional template parameter? Given that this is one of the methods to extend the library, it would make sense that one wishes to do so on conditions that enable_if can check. Albert

4 9

[Interprocess] Named objects with 'Managed External Buffer' (newbie)
by Jorge Bellon 25 Apr '14

25 Apr '14

Good afternoon, First, I apologize if I'm asking something obvious or outside the acceptable topics. I'm starting to use Boost so I'm quite newbie. I'm interested in using the managed_external_buffer in order to perform buffer copies into a created buffer that was created previously. Therefore, I will be storing mostly raw data into that buffer. Basically, I'm trying to do the following: Suppose a program uses the following int array: int numbers[10] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }; Eventually, I have to copy a chunk of that array into a pre-allocated buffer (i.e. the managed_external_buffer). Let the chunk be defined with: typedef struct { void* addr; size_t size; } chunk_t; However, these chunks can overlap, so I will sometimes merge two overlapping chunks into a bigger one. Example: // Chunk 1 chunk1_addr = (void*)&numbers[3]; chunk1_size = 3 * sizeof(int); // Chunk 2 chunk2_addr = (void*) &numbers[4]; chunk2_size = 4 * sizeof(int); The desired result is a single chunk containing {3, 4, 5, 6, 7}. The proposed problem is the merge, but how to find those chunks in the managed_external_buffer, so my question is the following: - Would it be possible to use named objects with another data type other than CharType and use managed_external_buffer::find to look for them? The thing is I could generate a hash or a numerical ID to identify the chunk. Generating a string using that number could be done but it would not be efficient. Otherwise, I guess I would have to keep a map (or other collection) with the <chunk ID, chunk pointer> pairs, define the managed_external_buffer with boost::interprocess::null_index (since I won't be using named objects) and use it through allocate and deallocate. Is this correct? Thanks in advance, Jorge WARNING / LEGAL TEXT: This message is intended only for the use of the individual or entity to which it is addressed and may contain information which is privileged, confidential, proprietary, or exempt from disclosure under applicable law. If you are not the intended recipient or the person responsible for delivering the message to the intended recipient, you are strictly prohibited from disclosing, distributing, copying, or in any way using this message. If you have received this communication in error, please notify the sender and destroy and delete any copies you may have received. http://www.bsc.es/disclaimer

2 1

[msm] compilation warning with boost-1.55.0
by samriti katoch 25 Apr '14

25 Apr '14

Hi, With boost-1.55.0 I see this warning from msm code: In file included from /build/boost/fusion/include/make_map.hpp:10, from /build/boost/msm/front/euml/common.hpp:40, from /build/boost/msm/front/euml/operator.hpp:15, from /build/abc.cc:15: cc1plus: warnings being treated as errors /build/boost/msm/back/fold_to_list.hpp:35: warning: 'boost::msm::back::states_' defined but not used What is a good way to remove this warning? Thanks! Samriti

2 2

Free Workshop: Test-Driven Development in C++ (Salt Lake City, UT)
by legalize+jeeves＠mail.xmission.com 25 Apr '14

25 Apr '14

[Please do not mail me a copy of your followup] This will be a practice run of my presentation for C++ Now! 2014. Workshop announcement: <http://bit.ly/RQgOtQ> Excerpt from the announcement: Test-Driven Development in C++, Wednesday, April 30, 2014 Have you heard about that new thing the kids are doing called test-driven development and wondered what it's all about? Is it about testing? Is it about design? Is it good or is it bad? Come join me for an evening workshop where I will show you what it's all about and you'll have a chance to try it out for yourself on a problem large enough to be interesting, but small enough that you can make progress on it during the workshop. The workshop will use the Boost.Test and Turtle libraries. Thanks to Fusion-io for the meeting facilities, WiFi access, food (pizza from The Pie) and refreshments. -- "The Direct3D Graphics Pipeline" free book <http://tinyurl.com/d3d-pipeline> The Computer Graphics Museum <http://computergraphicsmuseum.org> The Terminals Wiki <http://terminals.classiccmp.org> Legalize Adulthood! (my blog) <http://legalizeadulthood.wordpress.com>

1 0

circular buffer in a multithreaded program
by Sebastian Gesemann 24 Apr '14

24 Apr '14

Hello! I had some troubles with using boost::circular_buffer in a multithreaded application and I'm not really sure whether I actually ran into a bug or wether I expected just too much that wasn't promised in the thread-safety section. Anyhow, I wanted to share my story and a theory of what possibly went wrong. Maybe this posting even contains some ideas of how circular_buffer could be made a little more thread-safe without ading any mutex- or atomics-based synchronization. What I tried to do: I tried to grant one thread write access to a sub-range in a circular_buffer while another thread had read-access to a non-overlapping sub-range. At no time any capacity change was needed. Occasionally, in a reader thread I would "consume" some of the values that were already "committed" by a writer and make more room for the writer to store new data by - locking a mutex - calling cb.erase_first(n); - calling cb.resize(cb.capacity()); - notify writer that there is new free space to write stuff into - unlocking the mutex As for iterator invalidation, erase_first just invalidates iterators to the elements being removed. And resize in this case just increases the size again to the capacity which should not invalidate any iterators If I understand correctly. But the program did not work. The first thing that came to my attention was that the checked iterators of circular_buffer don't support this kind of multithreading as they register and unregister themselves into a linked list without any synchronization. But even after disabling the checked iterators via BOOST_CB_DISABLE_DEBUG, the program still did not work. I could not figure out why (with enough certainty) and eventually replaced circular_buffer with a custom vector-based data structure. My guess is that the iterators of a circular_buffer somehow depend on some part of the state of the buffer that is modifed by erase_first. Then, I would have a data race. But such a dependency does not really have to be there. In my own implementation, an iterator is "self-sufficient" in the sense that it does not need to access any of the buffer's state (indices, counters and whatnot) to access the right elements. And this way, erasing some unneeded elements from the buffer while some other thread still works on other values in the buffer via iterators does not cause a data race. In my opinion, it's reasonable to expect something like this to work using a circular_buffer. Maybe someone knows more about how circular_buffer iterators are implemented and/or wants to improve the circular_buffer implementation w.r.t. thread-safety to support this kind of use. Since I switched to a custom data structure that is able to deal with this situation, I did not investiage this issue with circular_buffer any further. I already lost about a day because of this. I hope, this is of interest to somebody who wants to avoid exessive copying in the standard "producer-consumer / bounded-buffer pattern". Cheers! Sebastian

5 10

Memory leak in boost::filesystems::parent_path()?
by B.W.H. van Beest 24 Apr '14

24 Apr '14

Hi, The following minimal program (only 7 lines) causes valgrind to report 2 errors, in line6: Some somebody point me to why it is wrong? a.cpp: 1 #include <boost/filesystem.hpp> 2 3 int main( int, char** ) 4 { 5 boost::filesystem::path path0( "/a/b/c" ); 6 boost::filesystem::path path1 = path0.parent_path(); 7 } Compiling and running with valgrind: g++ -g -lboost_system -lboost_filesystem a.cpp -o a.exe valgrind ./a.exe This gives the following output. Note the errors. ==13303== Memcheck, a memory error detector ==13303== Copyright (C) 2002-2012, and GNU GPL'd, by Julian Seward et al. ==13303== Using Valgrind-3.8.1 and LibVEX; rerun with -h for copyright info ==13303== Command: ./a.exe ==13303== ==13303== Invalid read of size 8 ==13303== at 0x5B0A5C8: wcscmp (in /lib64/libc-2.18.so) ==13303== by 0x52CA5C4: std::moneypunct<wchar_t, false>::~moneypunct() (in /usr/lib64/libstdc++.so.6.0.18) ==13303== by 0x52CA638: std::moneypunct<wchar_t, false>::~moneypunct() (in /usr/lib64/libstdc++.so.6.0.18) ==13303== by 0x52C1304: std::locale::_Impl::~_Impl() (in /usr/lib64/libstdc++.so.6.0.18) ==13303== by 0x52C143C: std::locale::~locale() (in /usr/lib64/libstdc++.so.6.0.18) ==13303== by 0x5AA775E: __cxa_finalize (in /lib64/libc-2.18.so) ==13303== by 0x503DD72: ??? (in /usr/lib64/libboost_filesystem.so.1.53.0) ==13303== by 0x400EE69: _dl_fini (in /lib64/ld-2.18.so) ==13303== by 0x5AA73D8: __run_exit_handlers (in /lib64/libc-2.18.so) ==13303== by 0x5AA7424: exit (in /lib64/libc-2.18.so) ==13303== by 0x5A90BEB: (below main) (in /lib64/libc-2.18.so) ==13303== Address 0x604c038 is 0 bytes after a block of size 8 alloc'd ==13303== at 0x4C284B7: operator new[](unsigned long) (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so) ==13303== by 0x52CBC81: std::moneypunct<wchar_t, false>::_M_initialize_moneypunct(__locale_struct*, char const*) (in /usr/lib64/libstdc++.so.6 .0.18) ==13303== by 0x52C3807: std::locale::_Impl::_Impl(char const*, unsigned long) (in /usr/lib64/libstdc++.so.6.0.18) ==13303== by 0x52C42D1: std::locale::locale(char const*) (in /usr/lib64/libstdc++.so.6.0.18) ==13303== by 0x50451B1: boost::filesystem::path::codecvt() (in /usr/lib64/libboost_filesystem.so.1.53.0) ==13303== by 0x5046C7E: boost::filesystem::path::parent_path() const (in /usr/lib64/libboost_filesystem.so.1.53.0) ==13303== by 0x401843: main (a.cpp:6) ==13303== ==13303== Invalid read of size 8 ==13303== at 0x5B0A5C8: wcscmp (in /lib64/libc-2.18.so) ==13303== by 0x52CA4D4: std::moneypunct<wchar_t, true>::~moneypunct() (in /usr/lib64/libstdc++.so.6.0.18) ==13303== by 0x52CA548: std::moneypunct<wchar_t, true>::~moneypunct() (in /usr/lib64/libstdc++.so.6.0.18) ==13303== by 0x52C1304: std::locale::_Impl::~_Impl() (in /usr/lib64/libstdc++.so.6.0.18) ==13303== by 0x52C143C: std::locale::~locale() (in /usr/lib64/libstdc++.so.6.0.18) ==13303== by 0x5AA775E: __cxa_finalize (in /lib64/libc-2.18.so) ==13303== by 0x503DD72: ??? (in /usr/lib64/libboost_filesystem.so.1.53.0) ==13303== by 0x400EE69: _dl_fini (in /lib64/ld-2.18.so) ==13303== by 0x5AA73D8: __run_exit_handlers (in /lib64/libc-2.18.so) ==13303== by 0x5AA7424: exit (in /lib64/libc-2.18.so) ==13303== by 0x5A90BEB: (below main) (in /lib64/libc-2.18.so) ==13303== Address 0x604c268 is 0 bytes after a block of size 8 alloc'd ==13303== at 0x4C284B7: operator new[](unsigned long) (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so) ==13303== by 0x52CB6B1: std::moneypunct<wchar_t, true>::_M_initialize_moneypunct(__locale_struct*, char const*) (in /usr/lib64/libstdc++.so.6. 0.18) ==13303== by 0x52C3854: std::locale::_Impl::_Impl(char const*, unsigned long) (in /usr/lib64/libstdc++.so.6.0.18) ==13303== by 0x52C42D1: std::locale::locale(char const*) (in /usr/lib64/libstdc++.so.6.0.18) ==13303== by 0x50451B1: boost::filesystem::path::codecvt() (in /usr/lib64/libboost_filesystem.so.1.53.0) ==13303== by 0x5046C7E: boost::filesystem::path::parent_path() const (in /usr/lib64/libboost_filesystem.so.1.53.0) ==13303== by 0x401843: main (a.cpp:6) ==13303== ==13303== ==13303== HEAP SUMMARY: ==13303== in use at exit: 0 bytes in 0 blocks ==13303== total heap usage: 483 allocs, 483 frees, 34,115 bytes allocated ==13303== ==13303== All heap blocks were freed -- no leaks are possible ==13303== ==13303== For counts of detected and suppressed errors, rerun with: -v ==13303== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 2 from 2)

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cmake + CUDA 6 + clang + boost errors on OS X Mavericks
by John Owens 24 Apr '14

24 Apr '14

Greetings, I’m using boost (1.55) (installed via macports) on: - OS X Mavericks - using clang (5.1, the Xcode default version, LLVM 3.4) - with CUDA 6 - and cmake (2.8.12.2). It has a large number of compile errors, shown here: http://pastebin.com/Qg2V0UwM that begin with: /opt/local/include/boost/type_traits/is_abstract.hpp(72): error: identifier "__is_abstract" is undefined I’d be delighted to have any advice on how to do cmake + CUDA 6 + clang + boost on OS X! JDO

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include error in OS X 10.9.2
by Freddy Martinez Garcia 22 Apr '14

22 Apr '14

Hi guys I’m trying to use mongodb in my develop. MongoDB use Boost library in its implementation… I had installed boost 1.55 with macport… the problem is when the mongo c++ driver import son files like: #include <boost/function.hpp> and this file does not exists in my system… How can I fix this in Mac ?? I’m new in os x, because in linux I don’t have this error… best regards freddy

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[Boost][Graph] vf2 implementation question
by Marc Viala 20 Apr '14

20 Apr '14

Hi, Recently,I tried to use Boost.Graph's VF2 implementation and after having played few days with this module, I was wondering if this implementation supports "adjacency_matrix" model as explained by the documentation (cf. http://www.boost.org/doc/libs/1_55_0/libs/graph/doc/vf2_sub_graph_iso.html) To demonstrate my point, you will find hereafter an C++ example extracted from the Boost.Graph's documentation. If the macro "ADJACENCY_LIST_STRUCT" is commented out, this code can't be compiled w/ VS2012 aka VC11 because the static assertion @line 837 of "boost/graph/vf2_sub_graph_iso.hpp" is triggered. My questions are: - Does this VF2 implementation supports "adjacency_matrix" model? - Is there any patch for supporting this model of graph? FYI: If I comment two static assertations in file "boost/graph/vf2_sub_graph_iso.hpp", at line 837 and line 843, the code compiles and runs correctly for "adjacency_matrix" model. #include <boost/graph/adjacency_list.hpp> #include <boost/graph/adjacency_matrix.hpp> #include <boost/graph/vf2_sub_graph_iso.hpp> using namespace boost; //#define ADJACENCY_LIST_STRUCT int main() { #ifdef ADJACENCY_LIST_STRUCT typedef adjacency_list<vecS, vecS, undirectedS> graph_type; #else typedef adjacency_matrix<undirectedS> graph_type; #endif // Build graph1. const int num_vertices1 = 8; graph_type graph1(num_vertices1); add_edge(0, 6, graph1); add_edge(0, 7, graph1); add_edge(1, 5, graph1); add_edge(1, 7, graph1); add_edge(2, 4, graph1); add_edge(2, 5, graph1); add_edge(2, 6, graph1); add_edge(3, 4, graph1); // Build graph2. const int num_vertices2 = 9; graph_type graph2(num_vertices2); add_edge(0, 6, graph2); add_edge(0, 8, graph2); add_edge(1, 5, graph2); add_edge(1, 7, graph2); add_edge(2, 4, graph2); add_edge(2, 7, graph2); add_edge(2, 8, graph2); add_edge(3, 4, graph2); add_edge(3, 5, graph2); add_edge(3, 6, graph2); // Compute de subgraph isomorphing. vf2_print_callback<graph_type, graph_type> cb(graph1, graph2); vf2_subgraph_iso(graph1, graph2, cb); } Best regards, Marc

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[Iostream] how to build iostream with zlib on windows
by Pritesh Acharya 18 Apr '14

18 Apr '14

Boost version: 1.55.0 OS: Windows 8 IDE: Visual Studio 2010 Is there a good tutorial on building boost iostream with zlib on windows. I looked over reference manual but with no solution. I did download zlib dll and source code and made reference in visual studio. I have link error on gzip_decompressor();

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Using metric_tsp_approx with bundled properties
by Alexis Praga 18 Apr '14

18 Apr '14

Hi, I am trying to use metric_tsp_approx on a graph defined as : typedef adjacency_list<vecS, vecS, undirectedS, City, Road> Graph; City contains the vertex id and Road the edge weight. After reading the documentation, I arrived to : metric_tsp_approx(g_init, weight_map(get(&Road::length, g_init)). vertex_index_map(get(&City::id, g_init)), make_tsp_tour_visitor(back_inserter(c))); I have compilation errors however. The relevant part seems to be : /usr/include/boost/property_map/property_map.hpp:382:58: error: no type named ‘key_type’ in ‘struct boost::property_traits<boost::bgl_named_params<boost::bundle_property_map<boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, City, Road>, long unsigned int, City, int>, boost::vertex_index_t, boost::no_property> >’ Any help appreciated, thanks. -- Alexis Praga, PhD Student (CERFACS) GPG key : AD4A AF6D BB5C 042F 9422 1223 06E1 C1BF E287 65D0

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[asio]Does the function of async_read can find the tcp connection has closed?
by lx 18 Apr '14

18 Apr '14

hi all: I want to know async_read or async_write can detect the tcp connection has closed, or not? thank you

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[container] header reference for most containers is unavailable in Boost 1.55
by Adam Romanek 17 Apr '14

17 Apr '14

Hi! there's a problem with the documentation of most containers from Boost.Container in Boost 1.55. The problem is that hyper-links seem to be missing, i.e. I can't click on deque, list or map. However, the links to the reference of vector or string are fine... WBR, Adam Romanek [1] http://www.boost.org/doc/libs/1_55_0/doc/html/boost_container_header_refere…

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boost serialize issue when compile 64 bit application
by gary jiang 17 Apr '14

17 Apr '14

Hi all, I am compiling 64 bit application, and got lots of errors about boost serializer, but I don't have any issue when compile 32 bit application. Is there some attention when transform from 32 bit boost to 64 bit boost? Any advice would be appreciate, thanks in advance! PS: We used intel toolchain to compile boost, and tried with different boost version, still got same errors. Regards, Gary Main.o: In function `boost::archive::detail::iserializer<CMyText_iarchive, AtworkPathInfo>::load_object_data(boost::archive::detail::basic_iarchive&, void*, unsigned int) const': Main.cpp:(.text._ZNK5boost7archive6detail11iserializerI16CMyText_iarchive15AtworkPathInfoE16load_object_dataERNS1_14basic_iarchiveEPvj[_ZNK5boost7archive6detail11iserializerI16CMyText_iarchive15AtworkPathInfoE16load_object_dataERNS1_14basic_iarchiveEPvj]+0x4b): undefined reference to `void AtworkPathInfo::serialize<CMyText_iarchive>(CMyText_iarchive&, unsigned int)' Schedule.o: In function `boost::archive::detail::iserializer<CMyText_iarchive, GERINFO>::load_object_data(boost::archive::detail::basic_iarchive&, void*, unsigned int) const': Schedule.cpp:(.text._ZNK5boost7archive6detail11iserializerI16CMyText_iarchive11GERINFOE16load_object_dataERNS1_14basic_iarchiveEPvj[_ZNK5boost7archive6detail11iserializerI16CMyText_iarchive11GERINFOE16load_object_dataERNS1_14basic_iarchiveEPvj]+0x4b): undefined reference to `void GERINFO::serialize<CMyText_iarchive>(CMyText_iarchive&, unsigned int)' Images.o: In function `boost::archive::detail::iserializer<CMyText_iarchive, MNTINFO>::load_object_data(boost::archive::detail::basic_iarchive&, void*, unsigned int) const': Images.cpp:(.text._ZNK5boost7archive6detail11iserializerI16CMyText_iarchive9MNTINFOE16load_object_dataERNS1_14basic_iarchiveEPvj[_ZNK5boost7archive6detail11iserializerI16CMyText_iarchive9MNTINFOE16load_object_dataERNS1_14basic_iarchiveEPvj]+0x4b): undefined reference to `void MNTINFO::serialize<CMyText_iarchive>(CMyText_iarchive&, unsigned int)' Images.o: In function `boost::archive::detail::iserializer<CMyText_iarchive, VOLUMEINFO>::load_object_data(boost::archive::detail::basic_iarchive&, void*, unsigned int) const': Images.cpp:(.text._ZNK5boost7archive6detail11iserializerI16CMyText_iarchive13VOLUMEINFOE16load_object_dataERNS1_14basic_iarchiveEPvj[_ZNK5boost7archive6detail11iserializerI16CMyText_iarchive13VOLUMEINFOE16load_object_dataERNS1_14basic_iarchiveEPvj]+0x4b): undefined reference to `void VOLUMEINFO::serialize<CMyText_iarchive>(CMyText_iarchive&, unsigned int)' Info.o: In function `boost::archive::detail::oserializer<CMyText_oarchive, MAPPINGINFO>::save_object_data(boost::archive::detail::basic_oarchive&, void const*) const': Info.cpp:(.text._ZNK5boost7archive6detail11oserializerI16CMyText_oarchive14MAPPINGINFOE16save_object_dataERNS1_14basic_oarchiveEPKv[_ZNK5boost7archive6detail11oserializerI16CMyText_oarchive14MAPPINGINFOE16save_object_dataERNS1_14basic_oarchiveEPKv]+0x5a): undefined reference to `void MAPPINGINFO::serialize<CMyText_oarchive>(CMyText_oarchive&, unsigned int)' Info.o: In function `boost::archive::detail::iserializer<CMyText_iarchive, MAPPINGINFO>::load_object_data(boost::archive::detail::basic_iarchive&, void*, unsigned int) const': Info.cpp:(.text._ZNK5boost7archive6detail11iserializerI16CMyText_iarchive14MAPPINGINFOE16load_object_dataERNS1_14basic_iarchiveEPvj[_ZNK5boost7archive6detail11iserializerI16CMyText_iarchive14MAPPINGINFOE16load_object_dataERNS1_14basic_iarchiveEPvj]+0x4b): undefined reference to `void MAPPINGINFO::serialize<CMyText_iarchive>(CMyText_iarchive&, unsigned int)' make[1]: *** [service] Error 1 make[1]: Leaving directory `/home/gary/product_100/CoreService' make: *** [all] Error 1

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[container] vector::resize() - value-initialization vs default-initialization
by Adam Romanek 16 Apr '14

16 Apr '14

Hi! first, I'd like to focus on Boost 1.54. The documentation of boost::container::vector::resize(size_type) says the elements are *default constructed* [1]. The same applies to the respective constructor: boost::container::vector(size_type n). This is a significant deviation from what C++11 std::vector::resize(size_type) does as it *value-initializes* the new elements. Is the documentation of Boost.Container wrong in this case? Or the behavior of the container differs from the one defined by the standard? On the other hand in Boost 1.55 I see some changes related to the way elements are constructed (not mentioned in the release note). A new constructor and resize() method were added taking default_init_t to indicate default construction of new elements is desired. However, the documentation of boost::container::resize(size_type new_size, default_init_t) says the new elements are value initialized [2]. Note that the documentation of the respective constructor is correct and says the elements are default constructed. I also assume that the addition of the new constructor/resize method changed the behavior of the original constructor/resize method to be compliant with std::vector. Finally, @Ion: thanks for your good work on this library. I use it more and more often as it provides great features, useful especially in C++03 environments. If you want me to file any tickets on the above-mentioned issues please just say so. WBR, Adam Romanek [1] http://www.boost.org/doc/libs/1_54_0/doc/html/boost/container/vector.html#i… [2] http://www.boost.org/doc/libs/1_55_0/doc/html/vector.html#idp20954152-bb

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Build boost on OSX 10.9 with GCC 4.8
by Jürgen Simon 16 Apr '14

16 Apr '14

Hello, I have a somewhat specific problem. I need to build Boost 1.55 with the GCC 4.8 compiler on the mac. I have installed gcc-4.8 using homebrew. Using the GCC compiler instead of clang is non-negotiable in my case, because I require OpenMP which is not implemented in clang yet. Given that, I tried to build boost this way: export CC=/usr/local/Cellar/gcc48/4.8.2/bin/gcc-4.8 export CXX=/usr/local/Cellar/gcc48/4.8.2/bin/g++-4.8 export LD=/usr/local/Cellar/gcc48/4.8.2/bin/g++-4.8 ./bootstrap.sh —with-toolset=gcc-4.8 gives an error: Building Boost.Build engine with toolset gcc-4.8... Failed to build Boost.Build build engine Consult 'bootstrap.log' for more details apparently it does not recognize the gcc-4.8 toolkit. Using gcc instead does create the b2 script, but running the script as is also created trouble: ./bootstrap.sh —with-toolset=gcc ./b2 common.mkdir bin.v2/libs/atomic/build/gcc-4.2.1 common.mkdir bin.v2/libs/atomic/build/gcc-4.2.1/release common.mkdir bin.v2/libs/atomic/build/gcc-4.2.1/release/threading-multi gcc.compile.c++ bin.v2/libs/atomic/build/gcc-4.2.1/release/threading-multi/lockpool.o In file included from libs/atomic/src/lockpool.cpp:3: In file included from ./boost/atomic.hpp:12: In file included from ./boost/atomic/atomic.hpp:17: In file included from ./boost/atomic/detail/platform.hpp:22: ./boost/atomic/detail/gcc-atomic.hpp:961:64: error: no matching constructor for initialization of 'storage_type' (aka 'boost::atomics::detail::storage128_type') explicit base_atomic(value_type const& v) BOOST_NOEXCEPT : v_(0) specifying the toolkit gcc-4.8 here does actually do something: ./bootstrap.sh —with-toolset=gcc ./b2 -d 2 toolset=gcc-4.8 but it results in linker errors, like the following two examples: "g++-4.8" -Wl,-R -Wl,"/System/Library/Frameworks/Python.framework/Versions/2.7/lib" -Wl,-R -Wl,"/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/config" -o "stage/lib/libboost_iostreams.dylib" -Wl,-h -Wl,libboost_iostreams.dylib -shared -Wl,--start-group "bin.v2/libs/iostreams/build/gcc-4.8/release/threading-multi/file_descriptor.o" "bin.v2/libs/iostreams/build/gcc-4.8/release/threading-multi/mapped_file.o" "bin.v2/libs/iostreams/build/gcc-4.8/release/threading-multi/bzip2.o" -Wl,-Bstatic -Wl,-Bdynamic -lbz2 -Wl,--end-group ld: unknown option: -R "g++-4.8" -o "bin.v2/libs/atomic/build/gcc-4.8/release/threading-multi/libboost_atomic.dylib" -Wl,-h -Wl,libboost_atomic.dylib -shared -Wl,--start-group "bin.v2/libs/atomic/build/gcc-4.8/release/threading-multi/lockpool.o" -Wl,-Bstatic -Wl,-Bdynamic -Wl,--end-group ld: unknown option: -h I tried for two days without success to get GCC-4.8 and Boost to play ball together on the Mac. What am I missing? Kind Regards, Jürgen

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