February 2014 - Boost - lists.boost.org

[Boost-users] User/Owner Information And in Boost File System
by MANTOSH KUMAR 12 Feb '14

12 Feb '14

Hi All, Point::1 ====== boost::filesystem library is great. However I found that boost::filesystem has no interface to fetch about the owner(userid/groupid) of a particular file. "stat()" system call has been provided by POSIX compliance system to fetch this information. I am pretty sure that this must have been thought by boost community while designing boost::filesystem library and there would be valid reason not to provide such interface. However I just wanted to know the thought of boost community. Point::2 ====== The following is the code snippet: std::vector<boost::filesystem::path> vec; boost::filesystem::recursive_directory_iterator rbgnitr(p); boost::filesystem::recursive_directory_iterator renditr; for(boost::filesystem::recursive_directory_iterator itr = rbgnitr; itr != renditr; ++itr) { v.push_back(*itr); } In the above "rbgnitr" does represent the starting node in a directory. However It looked bit strange while "renditr" for end node(one beyond end). The end node renditr" is basically empty instance of class "recursive_directory_iterator"......Just wanted to know why this was designed in this way..... Thanks & Regards, Mantosh Kumar India

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Boost.Log crash - question on consequences of misconfiguration
by Pieter 12 Feb '14

12 Feb '14

LS, My question regarding Boost.Log is the following: could anything been said on what to expect when asking Boost.Log to write to a non-existing directory on a read-only drive? Does it keep trying to write or give up when the directory cannot be created, and would the user be informed in such a case? Background: today I ran into a problem using Boost.Log. I configured both a Console and a TextFile backend (both autoflushing) but happened to configure the latter wrongly- setting the location of the file on a not-existing directory on a read-only drive. This caused a program crash under certain circumstances - but no problems under other circumstances (related to the configuration of the application which should not be relevant here) - when it did crash, this happened after a few messages were logged. Crash happened shortly before program termination but before the main() function was terminated (for a while I thought I was seeing the problem described in the docs regarding the boost.filesystem related problem and it took me a while to learn this was not the case). Pieter

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GSOC 2014
by Petru Trimbitas 12 Feb '14

12 Feb '14

Hello, I saw that boost took part in gsoc 2013, will it take part also in 2014? Thanks

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Boost.Mixin library preliminary reviews
by Borislav Stanimirov 11 Feb '14

11 Feb '14

Hello, Boost.Mixin is a library I'm developing and I intend to submit it for review by the end of the month (most likely on Feb, 23). Source is here: https://github.com/iboB/boost.mixin Docs are here: http://ibob.github.io/boost.mixin/ There have already been two discussion on the subject: here: http://lists.boost.org/Archives/boost/2013/01/200598.php and here: http://lists.boost.org/Archives/boost/2013/07/205184.php They showed at least moderate interest in the library. Also I had a lecture about the library back in November on Open Fest 2013 Bulgaria (Unfortunately it's in Bulgarian. If you understand Bulgarian, you can find it here http://www.youtube.com/watch?v=3sTX8lUdp1c ) The feedback from the lecture has been very positive. I'm going to complete the documentation in the following day or two (it's 90% done as of now) and then focus on docs polish, like typos, structure, etc, and fixing any bugs that might arise. The library is being used in two active closed source projects, so any major bugs are highly unlikely. Currently, apart from jamfiles, there are project files for Visual Studio 2008 and 2012, QtCreator, and Code::Blocks in the repo for your convenience. Before I submit it for a formal review, It would be great if I could have some preliminary ones. Anyone is welcome with questions, suggestions, tips, and comments Thanks, -- Borislav

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[predef] Error in sparc.h
by Adam Wulkiewicz 11 Feb '14

11 Feb '14

Hi, There is an error in predef/architecture/sparc.h (http://github.com/boostorg/predef/blob/develop/include/boost/predef/archite…) in line 40 the operand of && is missing. Should there be something added there or should the operator be deleted? Should I create a ticket? Regards, Adam

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[githelp] git pull --recurse-submodules equivalent?
by Rene Rivera 11 Feb '14

11 Feb '14

In trying to set up my ISP account to do testing report generation I ran into a rather old git version, 1.7.2.5. Which doesn't support the "--recurse-submodules" option of pull. What is the equivalent for a pre 1.7.3 git? -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net -- rrivera/acm.org (msn) - grafikrobot/aim,yahoo,skype,efnet,gmail

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Fwd: possible bug: retrieve data using associative property maps with boost::bimaps - failed
by Aniket Pugaonkar 11 Feb '14

11 Feb '14

Hi, I am not sure whether this email got sent to the list because I received an email that I have to subscribe to the list before asking any question through email. Apologies for sending it again. thanks! I am facing compilation error in the following code. I do understand why the error is, but I could not find a good solution. Here is my code and question explained in detail *What I want to do:* I want to store a key- value pair where both key and its respective values is unique. But After I create a map, I want to use the VALUE and get the corresponding key. Essentially the best way is a bimap. So I do the following using associative property maps. *What I did:* 1. define a bimap (my_bimap ) 2. define associative property map for left view of bimap ( right_asso_bimap ) 3. define associative property map for right view of bimap ( left_asso_bimap ) 4. fill the bimap using *left* view associative property map. i.e. *use boost::put( left_asso_bimap, key, value )* 5. Now using *right* view associative property map, retrieve key for given value i.e. use *boost::get( right_asso_bimap, value )* My main motive is to use GET and PUT helper functions for insertion and retrieval from a bimap. Use PUT to insert in LEFT BIMAP. and Use GET to retrieve from RIGHT BIMAP. I know the error is because of non-const-ness of the iterators because of which I cannot de-reference using iterators. But what would be the alternative to this ? This link here explains how to define parameters for bimap in order for iterators to be mutable. http://www.boost.org/doc/libs/1_55_0/libs/bimap/doc/html/boost_bimap/the_tu… *But I get the error below: * In file included from main.cpp:2:0: /usr/local/include/boost/property_map/property_map.hpp: In instantiation of 'boost::associative_property_map<UniquePairAssociativeContainer>::value_type& boost::associative_property_map<UniquePairAssociativeContainer>::operator[](const key_type&) const [with UniquePairAssociativeContainer = boost::bimaps::views::list_map_view<boost::bimaps::relation::member_at::right, boost::bimaps::detail::bimap_core<int, boost::bimaps::list_of<long unsigned int>, mpl_::na, mpl_::na, mpl_::na> > boost::associative_property_map<UniquePairAssociativeContainer>::reference = const int&; boost::associative_property_map<UniquePairAssociativeContainer>::value_type = const int; boost::associative_property_map<UniquePairAssociativeContainer>::key_type = long unsigned int]': /usr/local/include/boost/property_map/property_map.hpp:357:54: required from 'Reference boost::get(const boost::put_get_helper<Reference, PropertyMap>&, const K&) [with PropertyMap = boost::associative_property_map<boost::bimaps::views::list_map_view<boost::bimaps::relation::member_at::right, boost::bimaps::detail::bimap_core<int, boost::bimaps::list_of<long unsigned int>, mpl_::na, mpl_::na, mpl_::na> > > Reference = const int&; K = int]' main.cpp:41:35: required from here /usr/local/include/boost/property_map/property_map.hpp:502:20: error: no match for 'operator[]' (operand types are 'boost::associative_property_map<boost::bimaps::views::list_map_view<boost::bimaps::relation::member_at::right, boost::bimaps::detail::bimap_core<int, boost::bimaps::list_of<long unsigned int>, mpl_::na, mpl_::na, mpl_::na> > >::C {aka boost::bimaps::views::list_map_view<boost::bimaps::relation::member_at::right, boost::bimaps::detail::bimap_core<int, boost::bimaps::list_of<long unsigned int>, *mpl_::na, mpl_::na, mpl_::na> >}' and 'const key_type {aka const long unsigned int}')* *return (*m_c)[k];* ^ Here my code. You can also see the code here on this website link:* http://coliru.stacked-crooked.com/a/59cbf2c564bf22b2 <http://coliru.stacked-crooked.com/a/59cbf2c564bf22b2>* #include <boost/bimap.hpp> #include <boost/property_map/property_map.hpp> #include <boost/bimap/property_map/set_support.hpp>#include <boost/bimap/list_of.hpp>#include <iostream> using namespace boost; int main() {typedef int vertex_descriptor_t;namespace bm = boost::bimaps;typedef bm::bimap< vertex_descriptor_t, bm::list_of<size_t> > vd_idx_bimap_t;typedef boost::associative_property_map<vd_idx_bimap_t::left_map> Lasso_vd_idx_bimap_t;typedef boost::associative_property_map<vd_idx_bimap_t::right_map> Rasso_vd_idx_bimap_t; // define bimap and assoc prop map for itvd_idx_bimap_t my_bimap;Lasso_vd_idx_bimap_t Lmy_asso_bimap(my_bimap.left );Rasso_vd_idx_bimap_t Rmy_asso_bimap(my_bimap.right); typedef typename vd_idx_bimap_t::value_type value_type; my_bimap.insert( value_type( 1, 100 ) ); my_bimap.insert( value_type( 2, 200 ) ); int z = 1; std::cout << "value = " << get ( my_bimap.left, z ) << std::endl; // prints correctly value = 100 // use left asso bimap for inserting to bimap boost::put( Lmy_asso_bimap, 3, 300 ); // correct // print bimap using *left view*for(auto t = my_bimap.left.begin(); t != my_bimap.left.end(); ++t) std::cout << t->first << " " << t->second << "\n"; int y = 2;*z **= boost::get( Lmy_asso_bimap, y ); // CORRECT OUTPUT for left view * std::cout << "value = " << z << std::endl; // Use right asso bimap to get key based on supplied value y = 100;*z = boost::get( Rmy_asso_bimap, y );* *// -->> ERROR HERE for right view* std::cout << "value = " << z << std::endl; // print map again. (*right view*)for(auto t = my_bimap.right.begin(); t != my_bimap.right.end(); ++t) std::cout << t->first << " " << t->second << "\n"; } Please let me know whether this is a potential bug, or the code semantics is incorrect. Or the current library cannot support this. ? Regards, Aniket Pugaonkar -- Thanks and regards, Aniket Pugaonkar -- Thanks and regards, Aniket Pugaonkar -- Thanks and regards, Aniket Pugaonkar

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[GSOC] Generalized Hypergeometric Functions.
by Anton Bikineev 10 Feb '14

10 Feb '14

Hi all. I just added a quick and naive implementation of Pade approximation for 1f1 and 2f1 hypergeometric functions based on Luke's book. You can find code here: https://github.com/AntonBikineev/math/blob/hypergeometric/ include/boost/math/special_functions/detail/hypergeometric_pfq_pade.hpp I also want to thank Christopher Kormanyos for many advices and help. Best regards, Anton.

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Attn: We need GSoC 2014 mentors for Boost!
by Niall Douglas 10 Feb '14

10 Feb '14

Dear Boost community, We are now just five days away from the closing date for Google Summer of Code 2014 registration. Last year's GSoC was a huge success, with Google funding work on Boost to the tune of $35,000 and paying over $8,000 in costs for three representatives of Boost to attend the GSoC mentor's summit at Google HQ. As part of filling in our application for 2014, we must supply to Google a list of potential GSoC mentors and potential GSoC projects for summer 2014. We do NOT want a repeat of 2012 when our application was rejected due to an insufficiently long list of prospective mentors and projects! At the time of writing, we have just *eight* prospective mentors, and we need more to be sure of being approved by Google! Therefore, if you think yourself able to mentor a student doing some work on Boost this summer, *please* consider adding a description of the proposed work item and your name to the list at https://svn.boost.org/trac/boost/wiki/SoC2014. If you want to know more about mentoring a Google Summer of Code funded student work before you nominate yourself, please feel free to ask on the main Boost developers mailing list boost(a)lists.boost.org. Thank you in advance for your time. Niall Douglas (Boost Google Summer of Code admin) Boris Schäling (Boost Google Summer of Code backup admin)

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[program_options] comma separated options
by Alain Miniussi 10 Feb '14

10 Feb '14

Hi, Someone asked me if it was possible to "easily" specify an option that would allow to specify a vector of values. The first options that came in mind was to use "multitoken". But that solution had to drawback in that situation: - ambiguous with respect to positional parameters - clumsy when you want to allow options to be specified in files, since you have to write: option 12 option 42 ... instead of: option 12 42 19 So I though about using a custom validator, which implies introducing a new type too, if I understand correctly. Something along the lines of: ======================= ... template<typename T> struct option_sequence { std::vector<T> values; }; template<typename T> void validate(boost::any& v, const std::vector<std::string>& values, option_sequence<T>* target_type, int) { namespace po = boost::program_options; namespace alg = boost::algorithm; std::vector<T> result; typedef std::vector<std::string> strings; for ( strings::const_iterator iter = values.begin(); iter != values.end(); ++iter ) { strings tks; alg::split(tks, *iter, alg::is_any_of(":")); for( strings::const_iterator tk = tks.begin(); tk != tks.end(); ++tk) { result.push_back(boost::lexical_cast<T>(*tk)); } } v = option_sequence<T>(); boost::any_cast<option_sequence<T>&>(v).values.swap(result); } int main(int argc, char* argv[]) { .... desc.add_options() ("values,v", po::value<option_sequence<int> >(), "a vector of ':' separated values as in \"12:42:-20\"."); =================== Obviously, one could think that some flexibility could be added (separators for starters) but you get the idea. Is that the right way to go (the intermediate option_sequence template seems clumsy for the user (but you need to distinguish from std::vector's) and if yes, could such a thing be added to the library ? (if yes a could propose a patch for consideration). Cheers -- ===================================== Alain Miniussi DSI/Pôle Génie Logiciel Scientifique Observatoire de la Côte d'Azur

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