March 2014 - Boost - lists.preview.boost.org

[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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