May 2015 - Boost - lists.preview.boost.org

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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[function_types] Pull request for library in 'develop'
by Edward Diener 02 May '15

02 May '15

Is there a maintainer for the function_types library ? Tobias Schwinger is listed as the maintainer but I do not believe he has been active in Boost for a long time. I have a pull request for the library. Can someone who has administrative rights for the library please look at it ?

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Re: [boost] Official JSON Package
by Michael Ainsworth 01 May '15

01 May '15

> Is there an official Boost package for reading and writing JSON data? >> >> Not on Boost, I would suggest you the RapidJSON. >> Do not use boost PropertyTree since you will face incompatibilities mainly >> with arrays. Given that JSON is a de-facto standard (along the lines of INI files and the like) would an official addition as a boost library be considered?

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Official JSON Package
by Michael Ainsworth 01 May '15

01 May '15

Is there an official Boost package for reading and writing JSON data? I know of JSON Spirit, but this is not (to my knowledge) official. I also know the Boost.PropertyTree works, but doesnot have full support. Michael

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