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[type_erasure] Downcasting is now possible
by Steven Watanabe 10 Mar '15

10 Mar '15

AMDG I've been asked about a function for downcasting an any several times, and I finally implemented it. Short story: you can now use dynamic_any_cast to convert between two arbitrary any types. Here's a quick example which tries to cast a boost::any equivalent to a boost::function equivalent. using plain_any = any<mpl::vector< copy_constructible<>, relaxed> >; template<class Sig> using any_function = any<mpl::vector< callable<Sig>, copy_constructible<>, relaxed> >; bool try_call(const plain_any& arg) { try { auto fun = dynamic_any_cast<any_function<void()> >(arg); fun(); } catch(bad_any_cast&) { return false; } return true; } void global_register() { register_binding<copy_constructible<>, void(*)()>(); register_binding<typeid_<>, void(*)()>(); register_binding<callable<void()>, void(*)()>(); } void do_something() { std::cout << 42 << std::endl; } int main() { global_register(); plain_any x = &do_something; if(try_call(x)) { std::cout << "x is a function" << std::endl; } plain_any y = 10; if(!try_call(y)) { std::cout << "y is NOT a function" << std::endl; } } The calls to register_binding are necessary for this to work, unfortunately. I don't think it's possible to implement dynamic_any_cast without some kind of registration, but at least it only needs to be called once for each concept/type combination. If anyone has any better ideas about how to handle this, I'd love to hear it. Comments, questions, and criticism are welcome. In Christ, Steven Watanabe

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Boost GSoC '15. Enchanced Vector and Deque Containers
by Pranav Vaish 10 Mar '15

10 Mar '15

Hello developers, My name is Pranav Vaish. I'm a second year Undergraduate in Computer Science at Indian Institute of Technology, Kanpur. I am extremely interested in doing a GSoC project on Enhanced Vector and Deque Containers. I have used std::vector and std::deque containers (Default C++ containers. Not C++11 ones) several times and am quite familiar with their usages, though not so much with their code . I am strong at programming in C++ but have never written any library code prior to this. I am competent at understanding and working with all algorithms necessary for this project. I have spent some time thinking about the problem for the competency test and I would like know if I am supposed to understand the code of the standard containers and modify the code to suit our purposes or to rewrite it all from scratch in my own way. Also must I have any knowledge about BOOST code? If yes, which part of it? Thank You, ------ Pranav Vaish

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[random][rational] Is there any standard way to generate a random rationals?
by Damian Vicino 10 Mar '15

10 Mar '15

Hi, I’m using Boost.Rational in a simulation program. for some experiment, I want to generate some random values between 2 rational numbers. I’m wondering if someone already worked on this.

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gSoC 2015 - Boost Document Library development Project
by Anurag Ghosh 10 Mar '15

10 Mar '15

Hello I'm Anurag Ghosh, a Computer Science student in 2nd year. I'm interested in working for Boost in GSoC 2015 and found the Boost Document Library development project really interesting. I'm reading the links provided on the page. Any pointers on how should I go about ahead after that ? Thanks Anurag Ghosh

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GSoC 2015 - Boost.uBLAS a library for matrix computations Project
by Yan Ni 10 Mar '15

10 Mar '15

Hello I'm Yan Ni, a CS undergraduate student in 4th year. I am interested in working for Boost in GSoC 2015 and found the uBLAS project very interesting. I've read some the codes on github and has written a little code (including a simple test) of Gaussian Elimination Algorithm as the competency test: https://github.com/leckie-chn/ublas. I've also read about Raj's post about the algorithms need to be implemented. And I think that the focus on this project are both accuracy (using some numerical algorithm instead of classical math methods)and speed (regarding cache & memory utilization). Please let me know your preference. Thank you. -- with kind regards ------------------------------------------------------------------ Yan Ni, undergraduate of Department of Computer Science, School of Electronic Engineering & Computer Science, Peking University

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Library for await and stackless coroutine emulation
by TONGARI J 10 Mar '15

10 Mar '15

Hi there, I just want to announce my recent work on a small library called `CO2`, which intend to emulate await/yield and stackless coroutine. https://github.com/jamboree/co2 This library depends on Boost.Preprocessor, while I'm not proposing this library to Boost at this moment, if there's much interest in this library, I'd think about it. The idea is based on N4286: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4286.pdf The library is still work in progress, but the core features are complete, so if you're interested in the resumable function proposal and don't have a tool to experiment with, this library may serve the purpose. You can find a more detailed description on the github page, if you want to know some number about performance, from a rough test borrowed from Boost.Coroutine (symmetric/performance_switch.cpp), the avg cpu cycles for context-switch are: Boost.Coroutine: 40 cycles CO2: 16 cycles built-in await: 9 cycles (compiled with MSVC14, x64) Feedbacks will be appreciated. Thanks

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Release 1.58. - Permission to merge Boost.Integer
by Vicente J. Botet Escriba 09 Mar '15

09 Mar '15

Hi, I forget to do the merge to master of the last 5 commits in https://github.com/boostorg/integer/commits/develop Please, let me know if I can do the merge? Best, Vicente

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[interprocess] BOOST_NO_SWPRINTF not honored...
by Joseph Van Riper 09 Mar '15

09 Mar '15

This might seem pedantic, but with Microsoft's compilers magnify this issue a bit. boost/interprocess/detail/win32_api.hpp, line 2255 (as of boost 1.57) uses std::sprintf even when BOOST_NO_SWPRINTF is defined. This causes a problem for some folks (like me), as VC++ 2013 (and possibly other Microsoft compilers) have set a pragma deprecating this function, which leads to outright compiler errors when compiled with #pragma strict_gs_check(on), as is required in some environments who are picky about security. I confess, I have not checked to see if interprocess still does this in the latest code, but if it doesn't, I wonder if it could use an alternative (Microsoft recommends sprintf_s, but you might know of something better). - Trey

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[1.58.0] Release Notes
by Daniel James 09 Mar '15

09 Mar '15

Hi, The beta release is coming up soon, so please can you add your release notes as necessary. Easiest way is probably to create a pull request at: https://github.com/boostorg/website/blob/master/feed/history/boost_1_58_0.q… thanks, Daniel

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[gsoc15]Request for feedback: Enhanced vector and deque containers proposal
by Sandilya Jandhyala 08 Mar '15

08 Mar '15

Hello Boost, My name is Sandilya Jandhyala, and I'm interested in the 'Enhanced vector and deque containers' project idea. I've prepared a first draft of my proposal. It can be viewed here: https://github.com/jysandy/boost-gsoc-proposal/blob/master/README.md I haven't included my solution to the programming competency test, since I don't want it to be copied. I'd appreciate feedback/suggestions/criticisms, since I feel that the proposal still has some room for improvement. I'd also appreciate suggestions for additional features. Thanks, Sandilya

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