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Re: [boost] Interest in a container which can hold multiple data types?
by James Armstrong 05 May '15

05 May '15

On 5/5/2015 7:49 PM, Joaquin M Lopez Munoz wrote: > TONGARI J <tongari95 <at> gmail.com> writes: > >> If the data sequence shows some affinity, I guess an ordered >> tuple_vector-based sequence can provide some performance benefit in >> traversal (with some crafted for_each method). >> >> That is, a sequence of [AAABBB] may be traversed faster than [ABABAB] for >> such a container, and I believe in the later case such that the types are >> uniformly distributed, vector<variant> will perform better. > I wrote something on this some time ago, maybe worth having a look at: > > http://bannalia.blogspot.com/2014/05/fast-polymorphic-collections.html > http://bannalia.blogspot.com/2014/05/fast-polymorphic-collections-with.html > Nice analysis. If we can identify different use cases, we may be able to come up with several implementations of heterogeneous containers which balance efficiency and flexibility. I think it would be an interesting project to work on and surely useful if the containers all the a similar 'feel' -- James Armstrong

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[filesystem] copy_file compilation error
by Rob Conde 05 May '15

05 May '15

In boost 1.55 the following code compiled file on visual studio 2013 and g++ 4.4.7: #include "boost/filesystem/operations.hpp" void myFunc() { using namespace boost::filesystem; copy_option opt(copy_option::overwrite_if_exists); copy_file(path("p1"),path("p2"),opt); } in boost 1.58 I get the following error on g++ 4.4.7 (Visual Studio 2013 continues to work): test.cpp: In function 'void myFunc()': test.cpp:9: error: no matching function for call to 'copy_file(boost::filesystem::path, boost::filesystem::path, boost::filesystem::copy_option&)' boost/filesystem/operations.hpp:494: note: candidates are: void boost::filesystem::copy_file(const boost::filesystem::path&, const boost::filesystem::path&, boost::filesystem::copy_option::enum_type) boost/filesystem/operations.hpp:500: note: void boost::filesystem::copy_file(const boost::filesystem::path&, const boost::filesystem::path&) boost/filesystem/operations.hpp:505: note: void boost::filesystem::copy_file(const boost::filesystem::path&, const boost::filesystem::path&, boost::filesystem::copy_option::enum_type, boost::system::error_code&) boost/filesystem/operations.hpp:511: note: void boost::filesystem::copy_file(const boost::filesystem::path&, const boost::filesystem::path&, boost::system::error_code&) is this a bug in filesystem on gcc, a bug in gcc, a non-standard behavior in visual studio 2013, or an intended change? Rob Conde

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Re: [boost] Description of pre-requisites for building Boost 1.58.0?
by Marko Asplund 05 May '15

05 May '15

On 2015-04-24 22:17:55 Ben Pope wrote: > This doesn't really answer the question, but as a practical note, you > can do: > sudo apt-get build-dep libboost* > Which will install the build dependencies for the version of Boost in > your repository, rather than the version you're trying to build, but it > should get you where you want to be most of the time. FYI, I submitted a documentation pull request for adding a short section about pre-requisite software installation: https://github.com/boostorg/boost/pull/78 marko

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Another variant type (was: [peer review queue tardiness] [was Cleaning out the Boost review queue] Review Queue member requirements)
by Nevin Liber 05 May '15

05 May '15

On 2 April 2015 at 08:13, Niall Douglas <s_sourceforge(a)nedprod.com> wrote: > I > was recently working with eggs.variant for example, and that is Boost > quality written to Boost guidelines and yet I understand there is > zero interest in it entering Boost, despite it being superior to > Boost.Variant in almost every way. I don't remember anyone asking if they'd like to see this in Boost. Could you point to a thread? Even though you claim it is superior in almost every way, if I'm reading it correctly it has one fundamental difference in that it models "at-most-one-of" vs. Boost.Variant which models "exactly-one-of". And yes, I would like to see it in Boost, because as variant gets proposed for the standard, it would be better to have a lot more user experience to help us decide that fundamental question. That certainly fits the current mission in that "We aim to establish 'existing practice' and provide reference implementations so that Boost libraries are suitable for eventual standardization." -- Nevin ":-)" Liber <mailto:nevin@eviloverlord.com> (847) 691-1404

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Interested in contributing
by suryansh tiwari 05 May '15

05 May '15

Hey I'm new, but I'd like to contribute to your organisation, can someone please guide me along? I have done some good amount of competetive programming in c++ and I am completely new to open source.

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Re: [boost] Interest in a container which can hold multiple data types?
by James Armstrong 05 May '15

05 May '15

So, as it is currently implemented, it doesn't actually make use of boost::any or boost::variants. I used a deque<void*> to store addresses of the data, and deque<boost::core::typeinfo> to store the data types. Therefore, iterating through the container to get the data for datatype T simply involves iterating through the deque<boost::core::typeinfo> until a type match is found, then casting the void* to a T* for the corresponding index. There are definitely different ways to take the idea, and maybe there is use for multiple types of heterogeneous containers. The way this container is setup has the advantage (depending on your viewpoint) that you do not have to explicit declare what data types the container will store up front. This could be useful in some context where, for instance, you are pulling information from a database where you don't quite know up front whether certain fields will be numeric or character data until you've queried the db. This container can allow you to pop in whatever data-type the result is, without having to explicitly list out every possibility up front. -- James Armstrong

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[predef] Boost build errors using predef-check
by Edward Diener 04 May '15

04 May '15

In my jam file I have: import ../../predef/check/predef : check require : predef-check predef-require ; and in the requirments section of various Boost Build built-in rules I have: [ predef-check "BOOST_COMP_GNUC >= 4.3" : <cxxflags>-std=c++0x ] When I try to process my jamfile I get numerous warnings along the line of: > C:/Programming/VersionControl/modular-boost/libs/vmd/test\../../predef/check/pre > def.jam:61: in predef-check > warning: object is empty > Jamfile.v2:51: in modules.load > C:/Programming/VersionControl/modular-boost/tools/build/src/build\project.jam:32 > 5: in load-jamfile > C:/Programming/VersionControl/modular-boost/tools/build/src/build\project.jam:64 > : in load > C:/Programming/VersionControl/modular-boost/tools/build/src/build\project.jam:14 > 5: in project.find > C:/Programming/VersionControl/modular-boost/tools/build/src\build-system.jam:535 > : in load > C:\Programming\VersionControl\modular-boost\tools\build\src/kernel\modules.jam:2 > 89: in import > C:\Programming\VersionControl\modular-boost\tools\build\src/kernel/bootstrap.jam > :139: in boost-build > C:\Programming\VersionControl\modular-boost\boost-build.jam:17: in module scope > C:/Programming/VersionControl/modular-boost/libs/vmd/test\../../predef/check/pre > def.jam:61: in predef-check > warning: object is empty > Jamfile.v2:52: in modules.load followed eventually by: > C:\Programming\VersionControl\modular-boost\boost-build.jam:17: in module scope > Performing configuration checks > > - 32-bit : yes (cached) > - arm : no (cached) > - mips1 : no (cached) > - power : no (cached) > - sparc : no (cached) > - x86 : yes (cached) > - symlinks supported : yes > C:/Programming/VersionControl/modular-boost/tools/build/src/kernel\modules.jam:1 > 07: in modules.call-in > *** argument error > * rule ../../predef/check/predef.predef_check_action ( targets + : sources + : p > rops * ) > * called with: ( <p..\..\..\bin.v2\check\predef\gcc-mingw-4.9.2\debug\address-mo > del-32\architecture-x86>8bab483dffdbedc6438ba8af0f25a37e.txt : : <abi>ms <actio > n>@../../predef/check/predef%../../predef/check/predef.predef_check_action <addr > ess-model>32 <architecture>x86 <asynch-exceptions>off <auto-index-internal>off < > auto-index-no-duplicates>off <auto-index-section-names>on <auto-index-verbose>of > f <auto-index>off <binary-format>pe <debug-store>object <debug-symbols>on <doxyg > en.doxproc.index>no <doxygen.processor>xsltproc <embed-manifest>on <exception-ha > ndling>on <extern-c-nothrow>off <format>html <hardcode-dll-paths>true <host-os>w > indows <inlining>off <install-dependencies>off <link>shared <log-api>generic <mi > dl-robust>yes <midl-stubless-proxy>yes <optimization>off <os>NT <pch>on <predef- > expression>BOOST_COMP_GNUC >= 4.3 <preserve-test-targets>on <profiling>off <pyth > on-debugging>off <python.interpreter>C:/Utilities/Python278_32\python <python>2. > 7 <rtti>on <runtime-debugging>on <runtime-link>shared <stdlib>native <strip>off > <suppress-import-lib>false <symlink-location>project-relative <target-os>windows > <testing.execute>on <threadapi>win32 <threading>single <toolset-gcc:flavor>ming > w <toolset-gcc:version>4.9.2 <toolset>gcc <user-interface>console <variant>debug > <warnings-as-errors>off <warnings>on <windows-api>desktop : : : : : : : > : : : : : : : : ) > * missing argument sources > C:/Programming/VersionControl/modular-boost/libs/vmd/test\../../predef/check/pre > def.jam:99:see definition of rule '../../predef/check/predef.predef_check_action > ' being called > C:/Programming/VersionControl/modular-boost/tools/build/src/util\indirect.jam:98 > : in indirect.call > C:/Programming/VersionControl/modular-boost/tools/build/src/build\virtual-target > .jam:798: in class(a)action.actualize > C:/Programming/VersionControl/modular-boost/tools/build/src/build\virtual-target > .jam:311: in actualize-action etc. Any ideas of what is wrong ? Without the use of predef-check everything is OK. I have the latest 'develop' for predef and Boost build. I am trying to set gcc in c++11 mode for gcc 4.3 on up in my VMD tests.

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[predef] Using predef-require with OR conditions
by Edward Diener 04 May '15

04 May '15

In a jamfile I would like to use predef-require in OR situatuations so that if any particular predef-definition is true my unit testing rule occurs, else it does not occur: import ../libs/predef/check/predef : require : predef-require ; run some_test.cpp : : : BOOST_COMP_SOME_COMPILER >= n.n.n || other_predef_definiion ; The typical use case for this is to have a unit test for particular version(s) of a compiler or for all other versions of other compilers. Is this possible ?

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[afio] Trouble with examples
by Brian Ravnsgaard Riis 03 May '15

03 May '15

Hi, The first two examples for the AFIO library do not work as written. The "Hello World" example is missing a file_flag::Create[OnlyIfNotExist] flag on the "example_file.txt" op. Otherwise it never creates the file and the rest of the example becomes garbage. The "less toy" example has a bug in the parsing of the input files. It loops, incrementing argc instead of n, as it should. Even after that I cannot get the program to work, and I am unsure exactly what is wrong. The output file for the concatenated inputs is created and "truncated" to the correct size, but no data ever gets written to this file. If I use large files I have seen std::invalid_argument exceptions and even segfaults. I *think* the problem may be related to the buffers; I have tried using a simple std::vector<char> for the file_buffer_type, but this makes no difference. I have not looked at any other examples yet; I think I should get these two working correctly first... Regards, Brian

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Guidance on contributing to BOOST
by Rohith R 03 May '15

03 May '15

Hey All I am Rohith R, a budding developer from BITS Pilani University in India. Having used a lot of libraries from the STL and BOOST of C++ for my work as an application programmer and some data science projects, i wanted to contribute to BOOST by writing some code for it. I also have experience in writing low-level code for Operating Systems and I have written some basic drivers for raspberry pi as well. I want some guidance on this as to where should i start from and on what area should I focus my library on. This is a small implementation of vector i made just for fun. https://github.com/MadaraUchiha-314/Data-Structures-Library/blob/master/Vec… Any kind of help would be appreciated. Thanks A Lot Rohith R

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