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Turning Boost.Multi-Index ordered_non_unique index into ordered_unique one, with custom comparator
by Dominique Devienne 03 Mar '16

03 Mar '16

I would like to support a slightly unusual use-case. We have a class with a integer member, and a BMI container for instances of this class. That member is supposed to be unique, *except* for a special "invalid" value (-1), which several instances can use. Right now, we use an ordered_non_unique index, because of the -1's, but that leaves the door open for other duplicate "valid" values, which should be forbidden. So my question is whether one can index this member uniquely, thanks to a custom comparator, such that the comparator does not violate the usual strict-weak-ordering requirement of ordered containers? I'm thinking kinda like SQL NULLs, which don't compare equal to each other, i.e. in this case -1 would never equal another -1, and use another arbitrary (but stable) ordering specifically for those -1's. This assumes though I can know which instance the int member is part of, i.e. will the comparator get the integer by value or reference, and if a reference, is that a reference to the "internal" element, such that the arbitrary order can be the address of the element for example? Or to avoid element movement in case of reallocs in the container, can the comparator access an iterator to project it into another random-access index of the same container, to use that index's integer-index as the arbitrary order? I'd appreciate some feedback/insights into the above. Thanks, --DD

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Boost.Spirit Karma: Alternative generator
by Matwey V. Kornilov 03 Mar '16

03 Mar '16

Hello, I am construction karma::rule<OutputIterator, std::string()> which I would like to be either a string or quoted string if the string contains spaces. Now I think that the rule should be something like: rule = (&true[...] << string) | (lit("\"") << string << lit("\"")); but I've failed to write proper semantic action. How could I obtain std::string object reference to write something like: (obj.find(" ") == std::string::npos) ? Or maybe is there a better way to do the same?

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[gsoc16] An update on GSoC 2016 contingency plans
by Niall Douglas 03 Mar '16

03 Mar '16

Dear Boost, We've been collecting a list of veteran Summer of Code students where "veteran" means students whom have previously done a Google Summer of Code for Boost. It /may/ be possible for us to acquire enough funding from a number of contributors to tide over ongoing GSoC projects this summer during our year off from Google funding for veteran students only. The stipend to the student would be the same as with Google, $5,500. The mentor stipend would likely need to be waived under any substitute programme. We would therefore appreciate an update from student and/or mentor as to whether they were intending to submit a continuing GSoC this summer and would be willing to continue work on their Boost library under any funding we find. If we have forgotten any students or projects, please get in touch. Extant ongoing summer of code projects known to us are (please send corrections of any mistakes): * Boost Document, mentored by Antony Polukhin. https://anuragxel.github.io/boost-document/ Student: Anurag Ghosh Status: Not peer reviewed * Boost.Compute, mentored by Kyle Lutz. https://boostorg.github.io/compute/ Student: Jakub Szuppe Status: Official Boost library * Boost.Hana, mentored by Joel Falcou. https://boostorg.github.io/hana/ Student: Louis Dionne Status: Official Boost library * Boost.Http, mentored by Bjorn Reese. https://boostgsoc14.github.io/boost.http/ Student: Vinícius dos Santos Oliveira Status: One peer review held * Boost.Fixed-Point, mentored by Paul Bristow. https://github.com/BoostGSoC15/fixed_point Student: Nikhar Agrawal Status: Not peer reviewed We are aware of the following Boost libraries who have strong but new-to-Boost potential student candidates in the pipeline for summer of code 2016: * Boost.odeint, mentored by Karsten Ahnert and Mario Mulansky There is even less chance we can find funding for these, but if any of the veteran students or mentors has to suddenly pull out before the summer, we would substitute one of these projects instead. Therefore, if mentors had a really excellent student lined up for 2016, please let us know. None of the above should be read that summer of code 2016 is going ahead. We just need some hard numbers with which to lobby for funding. We will get back to the community as soon as we know more. We need all this information requested above back BEFORE this weekend as we will be making use of the Jacksonville ISO WG21 meeting currently happening to grab the right people to ask them for donations from their corporate bodies. If YOUR corporate org would be willing to help sponsor a summer of code student, either partially or in full, PLEASE get in touch. Donations to Boost are tax deductible for US taxpayers. Thank you all very much in advance! Niall --- Boost C++ Libraries Google Summer of Code 2016 admin https://svn.boost.org/trac/boost/wiki/SoC2016

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boost::asio::read_until Segmentation Fault & Third Party Signal Handler
by Craig, Tom 01 Mar '16

01 Mar '16

My Linux application sis using bool::asio::read_until() to read data from a socket. The application also uses commercial, 3rd party hardware. Occasionally my program crashes due to a SIGSEGV violation. The core dump stack trace is shown below. It indicates that the 3rd party signal handler is invoked while my thread is waiting for socket I/O, and that the crash is occurring during signal handler execution. While I recognize that this is an issue with the 3rd party vendor (and I am currently engaged in discussions with them), I'm wondering if my usage of boost is incorrect, or if there is something that I should be doing differently in performing socket I/O? I am using boost v1.43. [cid:image001.png@01D17303.98B2DD10] E. Thomas Craig Principal Software Engineer SWIFT Division KLA-Tencor Corporation 408-875-7909 (work) 650-799-4787 (cell)

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Boost.Spirit. Karma: Kleene star with space separator
by Matwey V. Kornilov 01 Mar '16

01 Mar '16

Hello There is an example of usage Keele star with Karma generator: http://www.boost.org/doc/libs/1_60_0/libs/spirit/doc/html/spirit/karma/refe… std::vector<double> v; v.push_back(1.0); v.push_back(2.0); v.push_back(3.0); test_generator_attr_delim("1.0 2.0 3.0 ", *double_, space, v); How could the remaining space be omitted? Is (double_ % space) supposed to be used instead for such cases?

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Re: [Boost-users] [boost] [Fit] upcoming formal review for Boost.Fit
by Paul Fultz II 29 Feb '16

29 Feb '16

On Sunday, February 28, 2016 at 5:28:39 PM UTC-6, Edward Diener wrote: > > On 2/28/2016 4:23 PM, paul Fultz wrote: > > > > > > > > > > On Sunday, February 28, 2016 12:23 PM, Edward Diener < > eldi...(a)tropicsoft.com <javascript:>> wrote: > > > > > >> > >> > >> On 2/27/2016 11:16 AM, Vicente J. Botet Escriba wrote: > >>> Dear Boost community, > >>> > >>> The formal review of Paul Fultz II's Fit library starts on Wednesday, > 2nd March and ends on 13th March. > >> > >> How do I generate the docs or run the tests for my local copy of Fit ? > > > >> > > > > You can build and run the tests by building the check target. For those > > unfamiliar with cmake, first configure the build directory with cmake: > > > > mkdir build > > cd build > > cmake .. > > cd .. > > > > Next build the check target using the native build system(such as make > or > > msbuild). CMake can call the native build system to build the target > 'check', > > like so: > > > > cmake --build build --config Release --target check > > > > Also, the library can be installed by invoking the 'install' target. > > Why is the CMakeLists.txt not in the 'test' subdirectory, since it > appears from your explanation that the file is used for the tests ? > Its used to install the library as well. > > > > > The documentation needs to be built using mkdocs. You can install mkdocs > and > > the boost theme with pip like this: > > > > pip install mkdocs mkdocs-boost > > > > Then to build the documentation, first `setup.py` must be run to extract > the > > documentation and examples from the source code, then `mkdocs` can be > invoked, > > like this: > > > > python setup.py > > mkdocs build -t boost > > > > And the documentation will be in the 'doc/html' directory. > > Please add these explanations to Fit as you are not using Boost build to > build the doc or run the tests. > I will add them. Also, I tried to add an initial Jamfile to build and run the tests as well. I just modified the Jamfile from other boost libraries. However, I haven't figured out how to run the tests yet using bjam to test my Jamfile. I get "error: Did not find Jamfile.jam or Jamroot.jam in any parent directory". I am not sure how I am supposed to run the tests. > > > _______________________________________________ > Unsubscribe & other changes: > http://lists.boost.org/mailman/listinfo.cgi/boost >

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[gsoc16] Boost rejected as GSoC 2016 org
by Niall Douglas 29 Feb '16

29 Feb '16

Dear Boost, It is with a heavy heart I write to say that Boost was rejected as an org for Google Summer of Code 2016 by Google. We had our application submitted in time, it was reviewed by three members of the Boost leadership, our ideas list had six solid ideas with an especially solid seventh on the way, we were in very good standing with Google and there was no reason to expect rejection. We have asked for clarification as to why we were rejected, and we shall try to improve our application next year to improve our chances. We recognise that many students and mentors will be extremely disappointed by this news. We share in that disappointment, and all we can say is please try again next year. For those students and mentors who are continuing a previous GSoC on an existing Boost library, there may be a possibility that Boost may be able to fund those continuations this year. Each case will be approached by the steering committee on a case by case basis, and be aware that the standard required for funding by Boost is considerably above that of Google's with an accompanying high and detailed standard of funding application to the steering committee. Contact us privately if you want to know more. On other news we had been expecting to announce today that Bryce Adelstein Lelbach has generously agreed to take over as secondary GSoC admin from Boris Schäling who has served Boost GSoC for something like four years now, so he has definitely earned himself a rest! Our thanks to Boris for his service, and welcome Bryce to the team! Finally, I'd like to thank Jon Kalb who moved heaven and earth as he always does to get the GSoC application submitted in time. Yours, Niall Douglas -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

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C++Now Student/Volunteers Call for Applications
by Jon Kalb 29 Feb '16

29 Feb '16

The Call for Applications for Student/Volunteers for C++Now 2016 (AKA BoostCon X) has been released: http://cppnow.org/2016-conference/announcements/2016/02/23/student-volunteer -program-accepting-applications.html The application submission deadline is March 16th. We are looking for students with a strong interest in C++. The opportunity is open to student of any level or any field of study. Jon Kalb Chair, C++Now 2016

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Re: [Boost-users] Boost.Context stack growing inwards
by Thomas Ziegenhagen 29 Feb '16

29 Feb '16

Hi again, just noticed that the make_fcontext() documentation says that it expects the stack pointer to be at the end or at the beginning, depending on the architecture. So please re-read my last mail as a feature request: If Boost.Context is a platform-independent context switching library, please make its stack pointer parameter also platform-independent. Rationale: Booost.Context knows best on which platform it runs. If the API is supposed to work the same on all supported systems, its parameter should do so, too. Other than that: Sorry for wasting your time. Bye, Thomas

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Boost.Context stack growing inwards
by Thomas Ziegenhagen 29 Feb '16

29 Feb '16

Hi there, I get regular crashes when using Boost.Context after just a few calls to make_fcontext(). I built a minimal example as follows: ---- #include <iostream> #include <vector> #include <boost/context/all.hpp> struct Context { boost::context::fcontext_t c_outside, c_inside; }; Context gContext = { nullptr, nullptr }; void DoIt( intptr_t /*pt*/) { uint8_t test[64]; memset( test, 0xaf, sizeof( test)); std::cout << "DoIt(), Point 1" << std::endl; boost::context::jump_fcontext( &gContext.c_inside, gContext.c_outside, 0, true); std::cout << "DoIt(), Point 2" << std::endl; boost::context::jump_fcontext( &gContext.c_inside, gContext.c_outside, 0, true); std::cout << "DoIt(), Point 3" << std::endl; boost::context::jump_fcontext( &gContext.c_inside, gContext.c_outside, 0, true); } int main() { const size_t StackSize = 16384; std::vector<uint8_t> stack( StackSize, 0xf1); gContext.c_inside = boost::context::make_fcontext( stack.data() + 256, stack.size() - 512, DoIt); std::cout << "main(), Point 1" << std::endl; boost::context::jump_fcontext( &gContext.c_outside, gContext.c_inside, 0, true); std::cout << "main(), Point 2" << std::endl; boost::context::jump_fcontext( &gContext.c_outside, gContext.c_inside, 0, true); std::cout << "main(), Point 3" << std::endl; boost::context::jump_fcontext( &gContext.c_outside, gContext.c_inside, 0, true); std::cout << "main(), Point 4" << std::endl; return 0; } ------ This notable thing is that I provide a stack with additional 256 bytes of safety borders. And it turns out: the provided memory is overwritten way beyond the beginning. The actual designated area is not touched at all, but instead the area before the beginning is overwritten. The only thing I found in the documentation is this: "sp Member: Pointer to the beginning of the stack (depending of the architecture the stack grows downwards or upwards)." which hints that on some system the stack might grow to negative addresses. But up to now I thought that boost.context knows which direction is correct, and adjusts the given pointer accordingly. But apparently it doesn't. Or the environment underwent a drastic change. Here it is Windows 10 64bit, Visual Studio 2015. For readers remembering my last mails: I have verified this also with an "classic" boost build using this command line: b2.exe -a --reconfigure variant=debug,release link=static runtime-link=static --with-context So I'm pretty sure it's not a build issue. Question: is this a bug? Probably not, I'm surely not the first to use Boost.Context, so I wonder what the correct way is to handle this issue. So what do I do about this? Thanks in advance Bye, Thomas

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