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[units] easier scaled units generation
by alfC 04 May '10

04 May '10

scaled units are a great feature of boost.units, however it seems complicated to (explicitly) create variables in such units. This is the way I found to create a variable that stores a quantity like GigaPascals: using boost::units; typedef make_scaled_unit<si::pressure, scale<10, static_rational< 9> > >::type gpa_unit; gpa_unit GPa; quantity<gpa_unit> p(1.*GPa); //or p(1.*si::giga*si::pascal); the question is, is there a simpler way of doing this? for example, just quantity<giga<si::pressure> > p = ...; //values are converted/stored in giga pascals. I could add some "metafunction": template<class Unit> giga{ typedef make_scaled_unit<Unit, scale<10, static_rational< 9> > >::type unit; }; and use it like quantity<giga<si::pressure>::unit> p; and even specialize for femto, atto, mega, kile, etc. I this already implemented in some other way? In this way if I had implemented an electronvolt unit I could have megaelectronvolt for free quantity<mega<electronvolt_unit>::unit> energy = ...; Thank you, Alfredo

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[ASIO] native back into local::stream_protocol
by Etienne Philip Pretorius 04 May '10

04 May '10

Hello List, I just need some guidance here. I have a parent process fork off a child and pass the int value to the child indicating what the native socket file descriptor it should use to receive communication from the parent process. I am just not able to get it placed back into a boost::asio::local::stream_protocol::socket object. Here is the code below, from the child process loaded via execlp: for(int i = 3; i < static_cast<unsigned char>(~0); i++) { if(i == boost::lexical_cast<int>(argv[0])) { continue; } close(i); } boost::asio::io_service io_service; boost::asio::local::stream_protocol::socket parent_(io_service); parent_.assign(boost::asio::local::stream_protocol, boost::lexical_cast<int>(argv[0])); Compiler error: g++ -c -g -MMD -MP -MF build/Debug/GNU-Linux-x86/main.o.d -o build/Debug/GNU-Linux-x86/main.o main.cpp main.cpp: In function ‘int main(int, char**)’: main.cpp:30: error: expected primary-expression before ‘,’ token Thank you, Etienne -- This message has been scanned for viruses and dangerous content by Pinpoint, and is believed to be clean.

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bjam fails on clang in unix
by Christopher Jefferson 04 May '10

04 May '10

It currently is not possible to build bjam with clang on unix, as the bjam files seems to be broken. Is there any change a bjam expert could have a quick look? Hopefully it will not require too major modifications. The darwin one works fine. I get the following output. The '-dumpmachine' flag appears to have been inherited from g++, and does not appear in clang. Even if I remove this, it still doesn't fix the rest of the problems. bash-4.1$ ./bjam clang: error: unsupported option '-dumpmachine' clang: error: no input files /scratch/boost-trunk/tools/build/v2/build/feature.jam:307: in implied-subfeature from module feature error: "unix" is not a known subfeature value of <toolset>clang /scratch/boost-trunk/tools/build/v2/build/feature.jam:491: in feature.validate-value-string from module feature /scratch/boost-trunk/tools/build/v2/build/property.jam:276: in validate1 from module property /scratch/boost-trunk/tools/build/v2/build/property.jam:301: in validate from module property /scratch/boost-trunk/tools/build/v2/build/property.jam:310: in property.validate-property-sets from module property /scratch/boost-trunk/tools/build/v2/build/toolset.jam:151: in toolset.flags from module toolset /scratch/boost-trunk/tools/build/v2/tools/common.jam:430: in common.handle-options from module common /scratch/boost-trunk/tools/build/v2/tools/clang-unix.jam:109: in clang-unix.init from module clang-unix /scratch/boost-trunk/tools/build/v2/build/toolset.jam:38: in toolset.using from module toolset /scratch/boost-trunk/tools/build/v2/tools/clang.jam:25: in clang.init from module clang /scratch/boost-trunk/tools/build/v2/build/toolset.jam:38: in toolset.using from module toolset /scratch/boost-trunk/tools/build/v2/build/project.jam:881: in using from module user-config /home/caj/user-config.jam:1: in modules.load from module user-config /scratch/boost-trunk/tools/build/v2/build-system.jam:257: in load-config from module build-system /scratch/boost-trunk/tools/build/v2/build-system.jam:399: in load-configuration-files from module build-system /scratch/boost-trunk/tools/build/v2/build-system.jam:554: in load from module build-system /scratch/boost-trunk/tools/build/v2/kernel/modules.jam:283: in import from module modules /scratch/boost-trunk/tools/build/v2/kernel/bootstrap.jam:142: in boost-build from module /scratch/boost-trunk/boost-build.jam:17: in module scope from module

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Problems with boost::asio::local::stream_protocol::iostream
by boost＠hannes.oib.com 04 May '10

04 May '10

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Re: [Boost-users] [serialization] void_caster fix ...
by Bogdan 04 May '10

04 May '10

I have created a small project that exhibits consistently the problem. This test comprises of the following components: - BaseDll.dll - TestSer.exe - linked with BaseDll.dll. - ExportDll.dll - linked with BaseDll.dll. There are three classe classes (all serializable): - polymorphic_base implemented inside BaseDll.dll; - polymorphic_derived1 derived from polymorphic_base and implemented inside BaseDll.dll - polymorphic_derived2 derived from polymorphic_base and implemented inside ExportDll.dll TestSer.exe loads ExportDll.dll dynamically via ::LoadLibrary() and calls the the function entry_point() exported by ExportDll.dll using ::GetProcAddress(). Both main() in TestSer.exe and entry_point() in ExportDll.dll create an object polymorphic_derived1 (i.e., the class defined inside BaseDll.dll) and display its address, respectively. Please note, there is no serialization involved. Results: ============================================================= Using boost 1.42 this test fails due to the ASSERT on symbol duplication in basic_serializer_map.cpp. After updating basic_serializer_map.cpp to the version that will eventually go in 1.43, this test fails with the error I described in detail in "[serialization] Potential problems with void_caster". If I change void_cast.cpp to the latest version ( I am afraid that is a post 1.43 version), everything works fine. Setup: ============================================================= I am using a debug build on Visual Studio 2008 Professional with SP1. OS - Windows XP Professional sp 3. The test is run with a version of the boost library built with the following command line bjam -q -a --layout=tagged --build-dir=C:\Downloads\boost_build --prefix=C:\_APP_\boost_1_42_0 --without-python --without-mpi toolset=msvc address-model=32 variant=debug link=static,shared threading=multi runtime-link=shared install In conclusion, if the latest version of void_cast.cpp is not going in boost 1.43, I believe the serialization library will have a problem with this scenario. Thank you, Bogdan

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(program_options) comment lines
by Lukas Diduch 03 May '10

03 May '10

using the config file parser of boost::program_options a line in of an ini file can be commented by using the '#' character, which seems to be a default. Is there a way to specify other comment characters as well (e.g. ';') ? Sincerely Lukas Diduch

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undefined reference to base_object
by John C 03 May '10

03 May '10

I am working with the boost 1.40.0 serialization library and I am having trouble with class registration for polymorphic types. The code I have has worked fine with VS2005 and VS2008 for a long time; however, in linux with gcc (4.4.1-4ubuntu9), I am having issues. I am using the non-intrusive serialization method on a class that resides in a shared object file. I have simplified this down to where the serialization of the object is performed in an executable linking in the shared object file. In Windows I am registering the classes with boost using BOOST_CLASS_EXPORT_GUID. However, in linux, if I register the classes using this macro, the code compiles but does not link and gives an error similar to below for : testConfig.o: In function `boost::archive::detail::iserializer<boost::archive::text_iarchive, MyNamespace::MyDerivedClass>::load_object_data(boost::archive::detail::basic_iarchive&, void*, unsigned int) const': testConfig.cpp:(.text._ZNK5boost7archive6detail11iserializerINS0_13text_iarchiveEN7MoreOfMyClassRelatredDataEE16load_object_dataERNS1_14basic_iarchiveEPvj[boost::archive::detail::iserializer<boost::archive::text_iarchive, MyNamespace::MyDerivedClass>::load_object_data(boost::archive::detail::basic_iarchive&, void*, unsigned int) const]+0x96): undefined reference to `MyNamespace::MyBaseClass& boost::serialization::base_object<MyNamespace::MyBaseClass, MyNamespace::MyDerivedClass>(MyNamespace::MyDerivedClass const&)' The same error also occurs with save_object_data. If I don't register, my test fails with the unregistered class exception. I have tried placing the macros in both a header and a source file and I still get the linker errors following advice from here: http://www.boost.org/doc/libs/1_40_0/libs/serialization/doc/special.html#ex…. I also tried explicitly instantiating the base_object methods, but get an error indicating no matching definition exists, so I am assuming this is related to the issue - I'm just not sure how else to define the function. I am familiar with basic templating, but the serialization library source is beyond me. Any help would be greatly appreciated..... Thanks - John -- View this message in context: http://old.nabble.com/undefined-reference-to-base_object-tp28417529p2841752… Sent from the Boost - Users mailing list archive at Nabble.com.

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boost.log library - backend sink
by junk bbb123 03 May '10

03 May '10

Hi, How can I create a backend sink that does the following: 1. set a backend sink to log into a file named: sample.log 2. once the log file exceeded a maximum limit of 10MB, the backend renames the filename to sample.old, and resumes logging into a new sample.log. the rotation settings as described in the documentation of boost.log don't suit my requirements, so how can I do what I mentioned above? Thanks

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mutable_queue usage
by Ralf Goertz 03 May '10

03 May '10

Hi, I don't seem to understand how to use mutable_queue correctly. The following crashes with *** glibc detected *** ./prior: free(): invalid next size (fast): 0x00000000006038e0 *** I guess that the third template parameter and/or the third constructor parameter cause the problem. #include <boost/pending/mutable_queue.hpp> typedef boost::mutable_queue<unsigned, std::vector<unsigned>, std::greater<unsigned> > Queue; int main() { boost::identity_property_map imap; std::greater<unsigned> comp; std::vector<unsigned> d; d.push_back(47); d.push_back(11); d.push_back(42); Queue q(d.begin(),d.end(),comp,imap); }

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How to use boost::function with boost::phoenix?
by Jens Mueller 03 May '10

03 May '10

Hi, I'm trying out boost:phoenix. Until now I used boost::lambda. I have code written using boost::lambda that returns a boost::function. E.g. boost::function<float(float)> flog() { using namespace boost::lambda; return bind(static_cast<float(*)(float)>(std::log), _1); } And with boost::lambda I can reuse the boost::function like this boost::function<float(float)> func = -bind(flog(), _1); to build bigger blocks. But I cannot make it work with boost::phoenix. boost::function<float(float)> func = -bind(flog(), arg1); does not compile. How do I use a boost::function within phoenix? Or what do I need to return instead of a boost::function to reuse it in phoenix? Basically I want to build more complex functions out of simple ones which are returned by some function to hide the internals of the function. I'm using Boost version 1.41.0 and g++ (Debian 4.3.2-1.1) 4.3.2. Jens

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