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[GSoC 2014] Http Server Proposal
by Vinícius dos Santos Oliveira 17 Mar '14

17 Mar '14

Hi guys, I'm interested in develop an asynchronous HTTP server for Boost as part of GSoC. The design would be inspired from Node.js without the facilities or inspirations that were created to overcome JavaScript quirks and limitations. The library would be modular to the point where you can use only small parts of it and you could also replace components that you don't like. The library should have a small overhead to be used on embedded projects, but the modular design will allow you to use higher abstractions when such concerns don't exist. Of course it's difficult to find the "right" answer to the problem, then I'll limit the higher-abstractions to "proven" techniques and avoid controversial features. I hope to give more details in the middle of the next week. The library will not be about writing template-driven web pages, but it will be about HTTP and you will be able to do things like video live stream via HTTP (try to do that with Django or PHP). I also intend to allow a efficient use in multithreaded environment with high-load of data (although network applications are usually I/O bound and not CPU bound). Of course it'll be possible to use WebSocket with this library too. Another thing I want to allow is to mock HTTP requests and transparently replace parts of the stack without affecting already written code. The purpose of this feature is to allow other transport mechanism such as FastCGI and also provide a future-proof approach by better allowing HTTP/2.0 when released. I would implement such library on top of Boost ASIO and I'd include facilities that I'm sure would work on long-term. Because the success of such project is very sensible to the chosen design, I'd limit its scope to things that I know it will work long-term. If the implementation project end up being too small, I can also implement WebSocket support (I had implemented it before and it wouldn't be such challenge for me), where the implementation effort is higher than the interface effort. I'm not sure about the deliverables (yet!), but I hope to give more details soon, once I have written nice texts. I'm particularly interested in an elegant way to represent some data structures, but I'll detail the plans soon (lots of text to write, ideas to explain and references to convince, among other). The text was a bit long, but it's because I already have something in mind. I hope to deliver a proposal explaining all the design, why I think it would work and other matters in the middle of the next week. I'm also open to suggestions and modifications in the not-yet-presented-proposal. I can provide background about my experiences later, but for now I want to know what do you guys think about the idea. TL;DR: For now I want to know what do you guys think about having a core HTTP server library in Boost. -- Vinícius dos Santos Oliveira https://about.me/vinipsmaker

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Library metadata
by Daniel James 17 Mar '14

17 Mar '14

Hi, I'm starting to add metadata to modules for updating the website, and hopefully other uses in the future. I added the metadata to Boost.Unordered and Boost.Functional to give you an idea of what this will look like: https://github.com/boostorg/functional/tree/develop/meta https://github.com/boostorg/unordered/tree/develop/meta You can see several libraries listed in the Boost.Functional file. I'll write some documentation soon, but it should be fairly easy to understand. I basically took what was in the website library list and split it up into modules. Quick summary of the fields: key - Used to be the website to identify each library. Don't change it, or the website will think it's a new library. boost-version - The version in which the library was released. name - The name of the library. authors - The authors of the library - will probably add a 'maintainers' field later. description - Library description - this is used in the library list, so keep it short. std-proposal - Is the library proposed for the standard. std-tr1 - Is the library part of TR1. category - The categories the library belongs to. one element for each category. The documentation will include a list of available categories. documentation - Path to the documentation. The documentation field is optional. If it isn't included, it'll use the default path: /libs/module-name/. If it is included, relative paths are resolved relative to the module directory, absolute paths from boost root - although I'd suggest you always use a path within the module, and if there's only a single library in a module, use the default path. This isn't the final format - I think the standards status fields could do with an overhaul to support C++11 etc. You also don't need to write the initial files yourself, I'll generate them and create pull requests once this is settled. Let me know what you think. thanks, Daniel

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Submitting Proposal
by Pulkit Mendiratta 17 Mar '14

17 Mar '14

Hello! I am not able to find a link to submit my proposal. After logging in to google-melange, and requesting a role from boost community, i am not able to find a link to submit it. -- Cheers, Pulkit Mendiratta

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Possible problem in boost::enable_if_c or MSVC 11
by Emil Dotchevski 17 Mar '14

17 Mar '14

I've noticed that for some reason some of the tests of the QVM library (which is in the queue for Boost review) are failing on MSVC 11. The tests that fail use boost::enable_if_c. Before I investigate further, I'm wondering if anyone else has had problems with enable_if_c and MSVC 11 (this code works with earlier versions of MSVC and with GCC.) Thanks, Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode

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Boost.odeint Applicant Test
by Zeshawn Shaheen 16 Mar '14

16 Mar '14

Hi, I am Zeshawn Shaheen, a junior at the University of the Pacific in Stockton, CA, US. I am a double major in computer science and mathematics and was interested in partaking in developing implicit routines for Boost.odeint. I've read in the Boost Developers Archive that a small test is given regarding the applicant's coding skills and the odeint library. I would appreciate it if I could be given the test. Thank you. Sincerely, Zeshawn Shaheen

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[GSoC 2014] [Computation of generalized hypergeometric functions]
by Cosmin Boaca 16 Mar '14

16 Mar '14

Hello, I am Cosmin Boaca, and I want to contribute to boost during GSoC 2014. Here is my proposal [0] . Please give me some feedback about it. [0] https://www.google-melange.com/gsoc/proposal/review/student/google/gsoc2014… Thank you, Cosmin Boaca

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Re: [boost] [GSoC] Boost.Thread executors proposal
by Ian Forbes 15 Mar '14

15 Mar '14

>First provide in addition a static polymorphic interface. The template >functions submit_at and submit_after would accept any chrono >`time_point` and `duration`. Is this with respect to the granularity of the time point? e.g. nano/micro/mille etc? If it is I'm assuming this would take an executor and then convert the time point to the desired granularity (nanoseconds by default) then add it to the executor. >Second, provide an adaptor that wraps an scheduled executor and makes it >a polymorphic one. Polymorphic with respect to what? >Third, provide an adaptor that wraps an executor, manage the time based >operations using a specific thread and forward all the operations to the >wrapped executor. So this would take a reference to an executor or a shared_ptr then spawn a single thread that would loop and add the submitted closures at the desired time to the given executor? Ian, ________________________________________ From: Boost [boost-bounces(a)lists.boost.org] on behalf of Vicente J. Botet Escriba [vicente.botet(a)wanadoo.fr] Sent: Friday, March 14, 2014 3:34 AM To: boost(a)lists.boost.org Subject: Re: [boost] [Boost.Thread][GSoC] Boost.Thread executors proposal Le 13/03/14 04:59, Ian Forbes a écrit : > Hi, > > Here is my GSoC proposal for working on the scheduled executors classes. It can be found here: www.cs.mcgill.ca/~iforbe/ > > This proposal mainly deals with the implementation of classes extending the `scheduled_executor` interface. I have already written thread pool implementations with very similar functionality to the ones proposed. > > I feel that the current proposal could use a little bit of touching up so please feel free to leave comments/criticisms. > > I would also be willing to take on any other work related to executors such the the dynamic/work-stealing thread pool implementation or the parallel algorithms library and add it into my proposal. > > Hi, I like your proposal on scheduled_executor and possibly extend it to a priority thread pool. I would let the work-stealing outside the proposal. Just to note that the closure would not be a std::function<void()> as this class doesn't accept a movable only function. Boost.Thread would include (version 1.56) a boost::executors::work as a type-erased class for closures. I'm looking for a different approach respect to scheduled work of the N3785 proposal. First provide in addition a static polymorphic interface. The template functions submit_at and submit_after would accept any chrono `time_point` and `duration`. Second, provide an adaptor that wraps an scheduled executor and makes it a polymorphic one. Third, provide an adaptor that wraps an executor, manage the time based operations using a specific thread and forward all the operations to the wrapped executor. What do you think of this approach? Best, Vicente _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost

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Re: [boost] [GSoC] pipelines questions
by Thaler Benedek 14 Mar '14

14 Mar '14

> I'm interested in the Boost.Pipelines proposal of GSoC 2014. [snip] Hi, I created a preview [0] with a working example. Please see the readme file and example/hello.cpp. This demo does not have parallel abilities and supports only 1-to-1 transformations in the pipeline. The purpose of this is to showcase my programming abilities and ask your opinions regarding the design and implementation. I intend to have this repository as a supplement of my proposal. Thanks, Benedek [0]: https://github.com/erenon/pipeline

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Permissions in boost::iostreams::mapped_file output
by Patrick Reynolds 14 Mar '14

14 Mar '14

Boost folks, Working with mapped_files in a project, I recently discovered that the files were being written to disk with unexpected permissions on the linux systems. I discussed this further in a pull request here: https://github.com/boostorg/iostreams/pull/2 Is this the proper avenue for making such a contribution? If not, where can I go to get started. Thanks, Patrick

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[modular-boost] Errors on submodule update
by Marcel Raad 14 Mar '14

14 Mar '14

Hi, I'm using TortoiseGit 1.8.7 with msysgit 1.8.5.2 on Windows and have checked out the develop branch of the boost repository. On every submodule update, I get the following errors. Is the submodule configuration corrupt? Git seems to believe that there are msm and polygon submodules which are not in the libs directory: ... git.exe submodule update -- "libs/msm" ... git.exe submodule update -- "libs/polygon" ... git.exe submodule update -- "msm" error: pathspec 'msm' did not match any file(s) known to git. Did you forget to 'git add'? git.exe submodule update -- "polygon" error: pathspec 'polygon' did not match any file(s) known to git. Did you forget to 'git add'? ...

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[Boost.Thread][GSoC] Boost.Thread executors proposal
by Ian Forbes 14 Mar '14

14 Mar '14

Hi, Here is my GSoC proposal for working on the scheduled executors classes. It can be found here: www.cs.mcgill.ca/~iforbe/ This proposal mainly deals with the implementation of classes extending the `scheduled_executor` interface. I have already written thread pool implementations with very similar functionality to the ones proposed. I feel that the current proposal could use a little bit of touching up so please feel free to leave comments/criticisms. I would also be willing to take on any other work related to executors such the the dynamic/work-stealing thread pool implementation or the parallel algorithms library and add it into my proposal. Thank, Ian

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[GSoC] [RFC] Proposal: A C++11 enabled TMP library
by Louis Dionne 14 Mar '14

14 Mar '14

Hi, As suggested earlier on this list, I am posting my GSoC proposal here in an attempt to gather comments and to improve the proposal. Basically, if you would not give the proposal 10/10, then I would like to know the reason so I can change it accordingly. I am strongly motivated with this project and I want to maximize my chances of getting in. The proposal is written in Markdown because that's easier to read than plain text; it is available here (secret gists are just hidden from search engines): http://gist.github.com/ldionne/d05528280db79105e30d Please post all constructive comments that come to your mind. Thank you, Louis Dionne

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GSoC Proposal for Boost.numeric.uBLAS (Review Request)
by Ganesh Prasad 13 Mar '14

13 Mar '14

Hi I have tried to write a feasible proposal for uBLAS, but I am not exactly sure about the time line I have proposed. I have considered my own efficiency and estimated the time considering the dependencies among the proposed algorithms. I will be glad to receive some advice regarding this project. Best Wishes Ganesh Prasad

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[atomic] gcc-atomic.hpp errors with Clang 3.4
by Richard Hadsell 12 Mar '14

12 Mar '14

I am trying to build Boost 1.55 libraries with Clang 3.4 using g++ 4.8.2 as the toolchain on CentOS 6.5. I think these errors arise from trying to initialize 128-bit integers with 0: clang-linux.compile.c++.without-pth bin.v2/libs/atomic/build/clang-linux-3.4/release/address-model-64/instruction-set-core2/link-static/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) ^ ~ ./boost/atomic/detail/gcc-atomic.hpp:932:28: note: candidate constructor (the implicit copy constructor) not viable: no known conversion from 'int' to 'const boost::atomics::detail::storage128_type' for 1st argument struct BOOST_ALIGNMENT(16) storage128_type ^ ./boost/atomic/detail/gcc-atomic.hpp:932:28: note: candidate constructor (the implicit default constructor) not viable: requires 0 arguments, but 1 was provided ./boost/atomic/detail/gcc-atomic.hpp:968:22: error: no viable conversion from 'int' to 'storage_type' (aka 'boost::atomics::detail::storage128_type') storage_type tmp = 0; ^ ~ ./boost/atomic/detail/gcc-atomic.hpp:932:28: note: candidate constructor (the implicit copy constructor) not viable: no known conversion from 'int' to 'const boost::atomics::detail::storage128_type &' for 1st argument struct BOOST_ALIGNMENT(16) storage128_type ^ Similar errors follow these. I think the initializations to 0 are superfluous, because they are followed by memcpy calls that overwrite them. I will try that fix myself, but I am looking for an official fix that will get into the next release. -- Dick Hadsell 203-992-6320 Fax: 203-992-6001 Reply-to: hadsell(a)blueskystudios.com Blue Sky Studioshttp://www.blueskystudios.com 1 American Lane, Greenwich, CT 06831-2560 Follow Blue Sky Studios on Facebook <http://www.facebook.com/BlueSkyStudios> and Twitter <http://twitter.com/#%21/blueskystudios>

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[1.55.0] link.jam: No such file or directory
by Richard Hadsell 12 Mar '14

12 Mar '14

I am trying to build Boost 1.55 libraries with Clang 3.4 using g++ 4.8.2 as the toolchain on CentOS 6.5. When I run the command that I used for building 1.52.0, I get a message that seems to be harmless but indicates something has changed in the bjam options: bin/bjam --user-config=user-config.LINUX_C65 threading=multi instruction-set=core2 address-model=64 variant=release link=static,shared --stagedir=stageC65 stage link.jam: No such file or directory ... What's up with that? -- Dick Hadsell 203-992-6320 Fax: 203-992-6001 Reply-to: hadsell(a)blueskystudios.com Blue Sky Studioshttp://www.blueskystudios.com 1 American Lane, Greenwich, CT 06831-2560 Follow Blue Sky Studios on Facebook <http://www.facebook.com/BlueSkyStudios> and Twitter <http://twitter.com/#%21/blueskystudios>

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[function] Multi-signature function?
by TONGARI J 12 Mar '14

12 Mar '14

Hi folks, I know it'd be better to say "overload", but I choose the word carefully because I'm aware of Boost.OverloadedFunction, which is not what I'm talking here (it's complementary, though). What I want is to have std/boost::function support multi-signature itself, instead of relying on some external wrapper which is less efficient. For example: struct A { int operator()() const; int operator()(int val) const; }; function<int(), int(int)> f(A{...}); f can store one instance of A internally, compared to the external approach, in which case each overload holds a standalone instance, plus the control data. I know Boost.Function has its baggage from C++98/03, so changing the interface may not be appropriate, in that case a new library can be considered (Boost.Overload?). A sample C++11 implementation can be found here: https://gist.github.com/jamboree/9489193 What do you think?

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[type_erasure] any_cast to a base class?
by Phil Endecott 12 Mar '14

12 Mar '14

Dear Experts, Can boost::type_erasure::any_cast cast to a base class? For example: class Base {}; class Derived: public Base {}; Derived d; any< ??? > a (d); Base* b = any_cast<Base*>(&a); assert(b); I know that this isn't possible with Boost.Any, but was hoping that Boost.TypeErasure would include some "magic" to make it possible. Failing that, are there any other options? (What I'd really like to do is to store a weak_ptr<Derived> and retrieve a shared_ptr<Base>, and other similar combinations, but I get stuck before I get that far.) Thanks, Phil.

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[spirit] hold_any missing assignment operator?
by Robert Carlsen 12 Mar '14

12 Mar '14

I ran into trouble when trying to do assignments between hold_any objects. The problem seems to be fixed by adding a missing assignment operator to basic_hold_any: basic_hold_any& operator=(basic_hold_any const& x) { return assign(x); } Here is some code that demonstrates the problem: int main(int argc, char* argv[]) { boost::spirit::hold_any v1 = std::string("val1"); { boost::spirit::hold_any v2 = std::string("val2"); v1 = v2; } return 0; } When executing that function, I get: *** Error in `./foo': double free or corruption (fasttop): 0x0000000001a50040 *** ======= Backtrace: ========= /usr/lib/libc.so.6(+0x731ff)[0x7f4800a331ff] /usr/lib/libc.so.6(+0x789ae)[0x7f4800a389ae] /usr/lib/libc.so.6(+0x796b6)[0x7f4800a396b6] /usr/lib/libstdc++.so.6(_ZNSsD1Ev+0x1f)[0x7f480133956f] ./foo[0x400e74] ./foo[0x400e10] ./foo[0x400cb7] /usr/lib/libc.so.6(__libc_start_main+0xf5)[0x7f48009e1b05] ./foo[0x400b04] ======= Memory map: ======== 00400000-00402000 r-xp 00000000 08:01 16813021 /home/robert/foo 00402000-00403000 rw-p 00001000 08:01 16813021 /home/robert/foo 01a50000-01a71000 rw-p 00000000 00:00 0 [heap] 7f48009c0000-7f4800b5e000 r-xp 00000000 08:01 6163783 /usr/lib/libc-2.19.so 7f4800b5e000-7f4800d5e000 ---p 0019e000 08:01 6163783 /usr/lib/libc-2.19.so 7f4800d5e000-7f4800d62000 r--p 0019e000 08:01 6163783 /usr/lib/libc-2.19.so 7f4800d62000-7f4800d64000 rw-p 001a2000 08:01 6163783 /usr/lib/libc-2.19.so 7f4800d64000-7f4800d68000 rw-p 00000000 00:00 0 7f4800d68000-7f4800d7d000 r-xp 00000000 08:01 6191352 /usr/lib/libgcc_s.so.1 7f4800d7d000-7f4800f7d000 ---p 00015000 08:01 6191352 /usr/lib/libgcc_s.so.1 7f4800f7d000-7f4800f7e000 rw-p 00015000 08:01 6191352 /usr/lib/libgcc_s.so.1 7f4800f7e000-7f480107e000 r-xp 00000000 08:01 6163651 /usr/lib/libm-2.19.so 7f480107e000-7f480127d000 ---p 00100000 08:01 6163651 /usr/lib/libm-2.19.so 7f480127d000-7f480127e000 r--p 000ff000 08:01 6163651 /usr/lib/libm-2.19.so 7f480127e000-7f480127f000 rw-p 00100000 08:01 6163651 /usr/lib/libm-2.19.so 7f480127f000-7f4801365000 r-xp 00000000 08:01 6191360 /usr/lib/libstdc++.so.6.0.19 7f4801365000-7f4801564000 ---p 000e6000 08:01 6191360 /usr/lib/libstdc++.so.6.0.19 7f4801564000-7f480156c000 r--p 000e5000 08:01 6191360 /usr/lib/libstdc++.so.6.0.19 7f480156c000-7f480156e000 rw-p 000ed000 08:01 6191360 /usr/lib/libstdc++.so.6.0.19 7f480156e000-7f4801583000 rw-p 00000000 00:00 0 7f4801583000-7f48015a3000 r-xp 00000000 08:01 6163762 /usr/lib/ld-2.19.so 7f4801778000-7f480177e000 rw-p 00000000 00:00 0 7f48017a1000-7f48017a3000 rw-p 00000000 00:00 0 7f48017a3000-7f48017a4000 r--p 00020000 08:01 6163762 /usr/lib/ld-2.19.so 7f48017a4000-7f48017a5000 rw-p 00021000 08:01 6163762 /usr/lib/ld-2.19.so 7f48017a5000-7f48017a6000 rw-p 00000000 00:00 0 7fff64671000-7fff64692000 rw-p 00000000 00:00 0 [stack] 7fff646a2000-7fff646a4000 r-xp 00000000 00:00 0 [vdso] ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall] Aborted (core dumped)

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Boost summer of formal reviews
by Borislav Stanimirov 12 Mar '14

12 Mar '14

Hello, This is a (half-)joke suggestion. There are currently 19 libraries in the review schedule ( http://www.boost.org/community/review_schedule.html ) which need a review manager (yes, including mine). Some of them have been there for years. Instead of focusing on getting people to write new libraries, which could potentially end up stuck in the review schedule (like AFIO), why don't we focus on getting the reviews for the ones that are already there. Or at least revising the review process. For example, I would be willing to review some of these libraries, but I am not qualified to be a review manager (since I am not very active in the community). I am not saying that most (or any) of the libraries stuck in review limbo, should pass the process, but some of them at least deserve a look (again, like AFIO). -- Borislav

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[GSoC 2014] [ Hypergeometric functions ] [ Complex Numbers Calculations ]
by Cosmin Boaca 11 Mar '14

11 Mar '14

Hello, I am Cosmin Boaca and I want to work during GSoC 2014 at the hypergeometric functions project. The project aims to approximate some hypergeometric functions for real values of their parameters. Even though the final result of the computation will be a real floating point number, some intermediate results would require complex numbers calculations such as the real power of a negative number, the square root of a negative number and also basic operations with complex numbers. My first question is : is there a way to do this operations using boost::multiprecision types such as cpp_dec_float and cpp_bin_float in order to store the real and the imaginary part of the complex number ? The second question is : Can I use the complex functions from the cstdfloat branch of Boost.math ? Thank you, Cosmin Boaca

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Boost.Align review manager approved
by Glen Fernandes 11 Mar '14

11 Mar '14

On February 25, 2014 Glen Fernandes wrote: >Ahmed, many thanks. :-) > >Some information about the role of a review manager: >http://www.boost.org/community/reviews.html#Review_Manager > >The next step, after you verify the submission code/documentation is >complete, would be to get in touch with the review wizard, Ron, > and finalize a date for the review. Ahmed, Ron just listed you as the review manager for Align. :-) Thanks again for volunteering. Glen

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Fwd: Regarding GSoc'14 Boost.odeint idea
by Rishav Agrawal 11 Mar '14

11 Mar '14

Sir/Mam, I, Rishav Agarwal, am a sophomore studing at the Indian Institute of Technology, Kanpur, India. I am interested in the working on implementing implicit routine for solving ODEs. I have done a semeser long on Numerical Methods in my third semester and am quite familiar with the algorithms used. Although I do not have much experience working with the Boost library, I am well aquaited with C++ and Python and can pick up the libraries easily. I would appreciate if the probable mentor could guide me through the application process and tell me about any pre-requisite/tests that I need to clear which could strengthen my proposal. A list of my previous projects can be found here <http://github.com/rra94>. Sincerely, Rishav Raj Agarwal I.I.T.Kanpur

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Standard C++ [Boost.Document] API
by pritesh vikram 11 Mar '14

11 Mar '14

Hello guys, As of having interested in Participating this year's Google Summer of Code Program. I am interested in developing Library which allow integration with spreadsheet application. Situation: As there is need for an API which understands all currently available formats of office applications running in different platforms. So API has to be aware of all formats available to all the platforms. There will be support for interconversion between these document formats.As well as classes and functions supporting to these operations.Conversion to portable formats like PDF. Proposed Solution: Separate components withing the library would be needed for Word processor, Spreadsheet, Presentation application.And also conversion code for each of these components with respect to different formats. Steps Involved: 1. Design all necessary components needed for the proposed solution. 2. Keeping informed to the mentor for the proposed design. 3. Implement using C/C++ as a language for the integration with the existing boost library. 4. Testing the Implemented model. 5. Getting the implemented code approved with the mentor. 6. Proceeding with the full implementation of the API. Benefits: 1. Help existing boost library users to take advantage of the creation, modification,conversion features for office documents. 2. No need for the users to look for another API for getting support for manipulation with office documents. As there is no existing work going on relating to this API.I am aware that all the libraries and components must be developed from scratch. I will move foreword with my above specified proposal for the project. If there is any more details to be included in the API i would like to informed for the additional details needed for this project to be fully integrated with all necessary components. If my proposal is effective then i would like to be appreciated that i am good to go for proposed layout with google summer of code program. Thanks, Pritesh Vikram

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boost::iterator_range does not work in boost::variant in boost 1.55
by Jon Biggar 11 Mar '14

11 Mar '14

If I try to put a boost::iterator_range into a boost::variant, it breaks the variant, because something in boost::iterator_range doesn't allow variant to use SFINAE deduction. My best guess at the problem is the declarations in boost/range/iterator_range_core.hpp that have a 'class ForwardRange' template argument are insufficiently constrained and accept almost anything as a possible ForwardRange type. I'm guessing that putting the correct enable_if<> template constraints on the templates that use 'ForwardRange' will fix the issue, but I'm having trouble identifing the correct metafunction test to use, since concept FowardRange concept doesn't have too many good targets. I'd like to test a candidate FowardRange type to see if boost::begin() and boost::end() can be successfully called on it, but I haven't figured out how to do that yet. Any suggestions? Known fixes or workarounds? I know about the has_range_iterator metafunction, but it can't be used here due to circular definition issues... Exmaple: #include <boost/variant.hpp> #include <boost/range.hpp> #include <boost/mpl/vector.hpp> using namespace boost; enum E { e1, e2, e3 }; typedef mpl::vector<E, std::string > args; typedef boost::make_variant_over<args>::type OkVariant; typedef mpl::vector<boost::iterator_range<std::string::iterator>, args> args1; typedef boost::make_variant_over<args1>::type BrokenVariant; int main(int argc, char **argv) { OkVariant ok; ok = e1; ok = ""; BrokenVariant broken; std::string s; broken = boost::iterator_range<std::string::iterator>(s.begin(), s.end()); broken = e2; broken = ""; } Yields errors on the last two assignments to 'broken' in g++4.8.2: test.cpp:27:12: required from here ./boost/mpl/eval_if.hpp:60:31: error: no type named 'type' in 'boost::mpl::eval_if_c<true, boost::range_const_iterator<E>, boost::range_mutable_iterator<const E> >::f_ {aka struct boost::range_const_iterator<E>}' typedef typename f_::type type; I've attached the full error log and my project-config.jam. -- Jon Biggar jon(a)floorboard.com jon(a)biggar.org jonbiggar(a)gmail.com

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Boost.Thread project for GSoC 2014
by Haoyue Wang 11 Mar '14

11 Mar '14

Hi, I am Haoyue, a PhD student in geophysics at MIT. I used C++11 to write parallel finite element codes in my research and had some coursework on concurrent programming. Boost is such a powerful and efficient library. I sincerely hope I could contribute to it this summer and beyond. I am interested in the standalone GSoC Projects under Boost.Thread. Particularly, the Work-Stealing-Thread-Pool project is a great one that I expect to learn a lot from. I understand that there could be much more to discuss once I have a preliminary proposal. Here I just want to ask if I am heading in the right direction. I think a good point to start is chapter 6, 7, and 9 of the book C++ Concurrency in Action: Practical Multithreading and the Executors and Schedulers revision 3 from http://www.open-std.org/. I haven't used Executor before but I am ware of its existence in Java for a while. Maybe I could go through some Executor and fork/join Java examples to see how they are used in practice. Finally, I will read and understand the executors codes on GitHub. I hope I could put up a good first draft proposal next Monday. If there is any advice, please let me know. Haoyue Wang

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