December 2012 - Boost-users - lists.preview.boost.org

(no subject)
by Rydinare 12 Dec '12

12 Dec '12

http://internetwealthbuilderinstitute.com/wp-content/plugins/akismet/google…

1 0

[Exception] Expected<T> C++03
by Szymon Gatner 12 Dec '12

12 Dec '12

Hi, I trying to implement Andrei's Expected<T> from his "Systematic Error Handling in C++" talk ( http://channel9.msdn.com/Shows/Going+Deep/C-and-Beyond-2012-Andrei-Alexandr…) in C++03 / BOOST In short: Expected<T> holds either T or exception_ptr holding exception that prevented T's creation. Think of single threaded future<T>. One of main purposes of this type is efficiency - code that computes T would normally throw in case of errors but instead it returns exception by value which causes Expected<T> to be initiated with exception type instead of actual value of T. Important part is that no throwing happens in library code (making it fast). As with future<T> throwing of stored exception only happens upon client's request - a call to get() in case of invalid computation (Expected<T>::valid() may be called beforehand to check if computation succeeded). To the point: Andrei's code uses std::make_exception_ptr() which I assume is std version of boost::copy_exception(). Now problem with copy_exception() is that it actually throws! So the whole idea of not throwing is gone by the fact that I don't know how to transform (const Exception&) into boost::exception_ptr (without throwing via copy_exception()). How does std::make_exception_ptr() work (as I assume it does not throw & return current_exception() as boost::copy_exception does)? Any suggestions welcome. Cheers. Szymon Gatner

3 3

boost::fusion::set
by Lukasz K 12 Dec '12

12 Dec '12

Could someone explain to me why the following is a valid definition of a boost::fusion::set? typedef boost::fusion::set<char,char,char> S; S s('a','b','c'); Especially, given that according to description: "set is an Associative Sequence of heteregenous typed data elements. Type identity is used to impose an equivalence relation on keys. The element's type is its key. A set may contain at most one element for each key. Membership testing and element key lookup has constant runtime complexity (see Overloaded Functions). " Src: http://www.boost.org/doc/libs/1_52_0/libs/fusion/doc/html/fusion/container/… Thanks, Lukasz

1 0

Compile boost for Windows Phone 8
by stren tler 12 Dec '12

12 Dec '12

Hi, i need to compile "date_time" and "system" for the windows phone 8 development enviroment. Any advice how setup bjam? thx

1 0

[serialization] performance issue when deserializing long string in a xml file
by jean-charles.quillet＠alyotech.fr 12 Dec '12

12 Dec '12

Hello, Since I discovered the boost serialization library, I'm using it in every single project I'm working on. I just cant figure how I was doing before. Makes life so much easier. I usually serialize all my objects in XML format. On my current project, I have a couple of big 500x500 complex matrices (ublas) that need to be serialized in my files. Serializing the matrices with the default boost functions results quite big files. So I've implemented the following: - I serialize the matrix in memory in binary format - I compress the data with the zlib - I encode the resulting data in base64 then copy it in a string - And I serialize the resulting string in my file It's working great but I've found out that deserializing this long string takes a huge amount of time. It bothers me and I don't really understand why. As I've got a filter reporting the bytes read to watch the progress. It seems that the time is spent after that all data has been read ! It confuses me. Has anybody experienced this or have any idea to solve my problem ? Thanks, Jean-Charles

2 3

Slow build with clang?
by Richard Hadsell 12 Dec '12

12 Dec '12

I have been building the Boost libraries with g++ for many years. Someone recommended trying Clang, so I downloaded 1.52.0 and built it first with g++ 4.5.1 on Fedora 14. Then I started a build with clang 3.3, and it is taking forever. I have not made any measurements, but it must be at least an order of magnitude slower than g++. The math library seems to take the longest, but maybe there are other slow-building libraries yet to come. Am I doing something wrong, or should I expect the clang build to be very slow? In myuser-config I have this: using clang : 3.3 : /directory_where_we_installed_clang/bin/clang :<compileflags>"-fPIC"<linkflags>"-fPIC" ; The command line is this: bin/bjam --user-config=myuser-config threading=multi instruction-set=core2 address-model=64 variant=release link=static,shared --stagedir=stageF14C clean The clang version is: clang version 3.3 (trunk 169541) (llvm/trunk 169537) The OS is Linux Fedora 14. -- Dick Hadsell 203-992-6320 Fax: 203-992-6001 Reply-to: hadsell(a)blueskystudios.com Blue Sky Studios http://www.blueskystudios.com 1 American Lane, Greenwich, CT 06831-2560

3 4

Regular expression problem using literals
by Neil Sutton 11 Dec '12

11 Dec '12

Hello, I am learning the basics of regular expression syntax and have been looking at the following example: #include <iostream> #include <fstream> #include <string> #include <boost/regex.hpp> #include <boost/xpressive/xpressive.hpp> using namespace boost::xpressive; int main() { std::ifstream input("myfile"); if(input) std::cout << "Success\n"; else std::cout << "fail\n"; std::string line; std::string data; while (getline(input, line)) { data += line; } std::string const &ref = data; mark_tag day(1), month(2), year(3), delim(4); sregex date = (month= repeat<1,2>(_d)) // find the month ... >> (delim= (set= '/','-')) // followed by a delimiter ... >> (day= repeat<1,2>(_d)) >> delim // and a day followed by the same >> (year= repeat<1,2>(_d >> _d)); // and the year. smatch what; if( regex_search(ref, what, date ) ) { std::cout << what[0] << '\n'; // whole match std::cout << what[day] << '\n'; // the day std::cout << what[month] << '\n'; // the month std::cout << what[year] << '\n'; // the year std::cout << what[delim] << '\n'; // the delimiter } return 0; } My problem is very simple and I am sorry to be asking about it. I want to include some literal wording in my regular expression. For example, before the program outputs the date it also searches for the words "Football results for" - (then date is output). Please can you show me how to prefix this regular expression with the literal words? My compiler see the 'for' as a c++ keyword, without more. Kind Regards

2 1

Property Tree with boost:any
by Olivier Tristan 11 Dec '12

11 Dec '12

Hello, I'm trying to use a property tree with a boost::any like in custom_data_type.cpp from the examples folder. So far, so good. My only issue arise when I'm trying to use write_json from json_parser. I understand that boost::any do not provide direct conversion to something that can be written into a stream, but I was wondering if there is a way to provide some conversion function just like it's done for get and put inside the property tree itself. Thanks ! -- UVI <http://www.uvi.net/> Olivier Tristan| Research & Development o.tristan(a)uvi.net Facebook <http://www.facebook.com/UVI.Official> Twitter <http://twitter.com/UVIofficial> Youtube <http://www.youtube.com/user/UVIofficial> SoundCloud <http://soundcloud.com/uvi-official> Blog UVI <http://blog.uvi.net/>

2 2

Building Boost for backwards compatibility
by Tim Burgess 11 Dec '12

11 Dec '12

Hi, I'm using Boost to build projects for the Mac. What I don't understand is how to build the libraries to support previous Mac OSX SDK versions. I'm having to build using XCode 4.5 on Mountain Lion (10.8), but want to ensure that my projects will run on 10.7 as a minimum. All advice gratefully accepted. Best wishes. Tim Burgess Raised Bar Ltd. Tel: +44 (0)1827 719822 Web: http://www.raisedbar.net

1 0

Registration for C++Now 2013 is now open
by Boris Kolpackov 11 Dec '12

11 Dec '12

The seventh annual C++Now Conference (formerly BoostCon) will be held at the Aspen Center for Physics in Aspen, Colorado, May 12th to 17th, 2013. "We are thrilled to announce the second annual C++Now conference, the whole-language edition of BoostCon covering all the coolest topics in C++," said Dave Abrahams, Conference Co-Chair. "In 2012, we broadened the conference scope by adding a third track and offering more C++11 coverage than any other event, and the community responded with an unprecedented number of registrations. In 2013, we are going to build on that success with foundational sessions integrating what we've all learned about using C++11 during the past year, while continuing the exploration of cutting-edge topics that BoostCon attendees have come to expect." Early Bird Savings Deadlines! Early Bird conference registration, which ends April 14th, 2013, costs $599. After that date, the registration fee is $699. Register now at our registration page <http://www.eventbrite.com/event/2717332615>. Early Bird hotel registration ends December 31st, 2012 and saves $20 per night. Please reserve your room using the Aspen Meadows online reservation system <https://resweb.passkey.com/go/cplusplusnow2013> Speakers If you are interested in presenting, we are currently accepting proposals <http://cppnow.org/2013-call-for-submissions/>. Registration fee is waived for one speaker of every standard session presentation. Shorter sessions are prorated. Student/Volunteers Registration fees will be waived for a limited number of individuals that wish to attend as volunteers. Volunteer work consists of helping to run the conference and will not prevent volunteers from attending sessions. This is the first year this opportunity is being offered. If you are interested in applying to attend as a volunteer, contact us at <organizers(a)cppnow.org>. Sponsors For a copy of the conference Sponsorship Prospectus contact sponsorship(a)cppnow.org. C++Now is presented by Boost in-cooperation with ACM. Permanent link for this announcement is: http://cppnow.org/2013-registration-announcement/

1 0