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[GIL] gil/metafunctions.hpp broken in 1.49?
by Andrew Hundt 12 Mar '12

12 Mar '12

I may be mistaken, but it looks like boost::mpl::vector_c may have been moved from <boost/mpl/vector.hpp> to <boost/mpl/vector_c.hpp> and it appears <boost/gil/metafunctions.hpp> has not been updated to reflect this change. Cheers! Andrew Hundt

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[fusion] Fusion using varidiac templates
by paul Fultz 12 Mar '12

12 Mar '12

hi, I remember seeing that there was an initial port of fusion to use variadiac templates a while back. Is that code available somewhere? If so, where could a find that? Thanks, Paul

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Using an element of a class A in a constructor of a class B (reflection with boost::python)
by christophe jean-joseph 12 Mar '12

12 Mar '12

Hello The situation is as follow. I have a C++ code that I haven't written and that I barely can modified. I am supposed to reflect this code in Python with boost. In the code, I have something looking like this: Class A_Base { A_Base(){}; ~A_Base(){}; Whatever virtual and pure virtual functions; } Class A_Derived{ A_Derived(Type1 arg1,...){whatever instructions;} ~A_Derived(){}; Whatever functions; } Class B { B(A_Base& aBase, double& x){}; ~B(){}; Whatever functions; } In the C++ main, at some point aDerived A_Derived is set, and then B(aDerived, x). I need to reflect that under python. Until now, I have been able, with a simple example, to reflect a function f, which is not a ctor, from a class B using A_Base& as argument type, but I can't figure out how to deal with it for a constructor. Based on: http://wiki.python.org/moin/boost.python/ExportingClasses I am declaring f under both its class B and A_Base as follow: .def("f", &B::f) But when I try this for a constructor as f, it refuse to compile. Anyone got a clue? Thank you very much in advance for any further help.

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Keynotes for C++ Now!
by Jon Kalb 12 Mar '12

12 Mar '12

C++ Now! (formerly BoostCon) is pleased to announce its lineup of keynote speakers for the 2012 conference: Howard Hinnant, Sean Parent, and Daveed Vandevoorde. Howard Hinnant is the principal author of libc++, the standard C++ library implementation used by the Clang compiler. During the development of C++11, Howard served as chairman of the C++ Standards Committee¹s Library Working Group, and is largely responsible for the design of what Scott Meyers has called the language¹s ³flagship new feature:² rvalue references. His keynote will demonstrate how rvalue references are used in move semantics and perfect forwarding. Sean Parent is a principal scientist and software architect for Adobe¹s mobile digital imaging group and formerly managed Adobe¹s Software Technology Lab. He was also the keynote speaker for the very first BoostCon, where he gave one of the most inspiring and memorable talks we¹ve ever had. We¹re very pleased to welcome him back for an encore. He will be speaking on what¹s next for C++ programmers: how do we write beautiful code that truly exploits today¹s hardware and infrastructure? Daveed Vandevoorde is a compiler developer with Edison Design Group, the author (with Nicolai Josuttis) of ³C++ Templates: The Complete Guide,² a co-founder of comp.lang.c++.moderated, and one of the few C++ Committee Members who is equally comfortable working on library design, language evolution, or the arcana of core language issues. Daveed is currently a leader in the effort to add true modules to the C++ language. He¹ll be talking about the design of the C++ modules feature and what it would mean for the future of the language. ³We are thrilled to have such a powerhouse lineup in the first year of the new language standard,² said Dave Abrahams the conference founder and co-chair. ³C++Now! 2012 is truly shaping up to be a feast for the C++ enthusiast.² C++ Now! 2012 will be held May 13-18 in Aspen Colorado. Registration is now open at http://cppnow.org/registration/. Keynote details at http://cppnow.org/overview/. Jon

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boost::algorithm::trim_copy() behaves like "strdup" in normal C, does it allocate a new string ?
by g.fanini＠gmail.com 11 Mar '12

11 Mar '12

Could I ask for a clarification whether boost::algorithm::trim_copy() behaves like "strdup" in normal C, i.e. does it allocate a new string ? or does it modify the passed string without allocating a new string ? It is not entirely clear from the documentation : http://www.boost.org/doc/libs/1_34_0/doc/html/boost/algorithm/trim_copy.html Because the argument passed has the modifier "const" I am led to believe it would leave the passed string unchanged, and return a newly allocated string. Possibly would you consider kindly updating the documentation reflecting the returned string is newly allocated.I am asking this becauseI am trying to work with preexisting boost code which uses boost::algorithm::trim_copy() profusely and I have severe leakage problems.Thank you for any information.

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[bgl] Update on maximum adjacency search
by Fernando Vilas 11 Mar '12

11 Mar '12

Hi, Since the last round of feedback, I think the implementation is at least closer to being releasable. This is not quite a re-send because I attached the wrong patch last time, but I also forgot the subject tags to get the attention of the BGL folks. Changes: - All parameters other than the graph itself are available as named parameters - Visitor is not pass-by-value like other search algorithms - Documentation created Still potential todo: - Update documentation with graphical walkthrough on a small graph - Find a way to make the priority queue work without unwrap_ref() - Do not depend on one_bit_color_map internals in min_cut_mas_visitor - Other suggestions from Boost community -- Thanks, Fernando Vilas fvilas(a)iname.com

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Re: [boost] Boost.ntree_container (bi_tree, quad_tree, oct_tree, etc ptr containers) Is there any interest in this?
by Dan Walters 11 Mar '12

11 Mar '12

Hi all, This is my current implementation of an oct tree that I am using on a project I am working on. It is a templated oct tree which serves as a pointer container. There is usage shown in the main() function at the bottom of the sample. http://codepad.org/yIAblSDN Please bear in mind it is not fully optimized or std compliant, just put together for a project but shows the intended basic functionality and method. Compatibility with boost geometry is a great suggestion. Again, I am mindful of defining the boundaries of this library, but if it makes sense then template specialization or utility code could be provided to use the libraries together easily and elegantly. k-d trees are very interesting, and if discussion found these potentially useful enough, they would certainly belong in the same library. I think, in any context, this should be thought of as a container library above all else and would be potentially useful not just in game or geometry programming, but open to use where ever useful, including as a memory efficient pointer container for sparsely populated multidimensional arrays. Best wishes, Dan On 10 March 2012 20:04, Daniel F. Savarese <dfs(a)savarese.org> wrote: > > In message <848178090.20120310163009(a)gmail.com>, pavel writes: > >by the way i have a ready implementation of kd trees (if anyone is > >interested): > > > > > http://programmizm.sourceforge.net/blog/2011/a-practical-implementation-of-… > >trees > > That's not exactly a generic implementation, nor one that is STL-friendly > (e.g., no iterators). For a more generic implementation that aims for STL > interoperability where possible, see the header-only libssrckdtree library: > http://www.savarese.com/software/libssrckdtree/ > > But this is off-topic for the thread, which--as I understand it--is > concerned > with fixed-size multidimensional spatial pointer containers oriented toward > 3D applications, not variable-sized multidimensional spatial value > containers > applicable to arbitrary domains. > > daniel > > > _______________________________________________ > Unsubscribe & other changes: > http://lists.boost.org/mailman/listinfo.cgi/boost >

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Re: [boost] Boost.ntree_container (bi_tree, quad_tree, oct_tree, etc ptr containers) Is there any interest in this?
by pavel 11 Mar '12

11 Mar '12

Daniel wrote on Sunday, March 11, 2012 at 0:04:28: > That's not exactly a generic implementation, nor one that is STL-friendly > (e.g., no iterators). you are perfectly right but i believe that this implementation can be almost trivially integrated with a generic (read: template) interface besides, i hardly see a kd tree or an octree as a (associative) container -- Pavel P.S. if you notice a grammar mistake or weird phrasing in my message please point it out

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[filesystem.v3] v1.49 Path constructor issue in VS Debug configuration
by Fraser Hutchison 11 Mar '12

11 Mar '12

Hello, The changes made to filesystem/v3/src/path.cpp between v1.48 and v1.49 seem to be causing a crash if I initialise a path as e.g. a global variable or as a static class member, but only for a Debug build. (I'm using VS10 on 64-bit Win 7). The following program exhibits this behaviour: |#include "boost/filesystem/v3/path.hpp" boost::filesystem::path p("p"); int main() { return 0; } | In Debug, I can see that the third path constructor calls |codecvt()|, which calls |wchar_t_codecvt_facet()|, which returns |codecvt_facet|. However, |codecvt_facet| hasn't been initialised at this point. This appears to only be the case for Debug builds though. I'm unclear as to whether this is an MSVC bug though. I thought that the Standard required |codecvt_facet| to have been initialised before |wchar_t_codecvt_facet()| since it comes earlier in the same translation unit. Could someone please clarify whether I should file a bug report with boost please? Thanks, Fraser.

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[range] MFC/ATL select_first / select_second specializations for map_keys and map_values adaptors
by Adam Walling 11 Mar '12

11 Mar '12

I enjoy using the range library, and also foreach. When dealing with legacy code, the MFC / ATL range adaptors are wonderful. Unfortunately, the CMap and CMapStringToString iterators return CPair objects rather than std::pair, hence causing the select_first / select_second_mutable / select_second_const metafunctions to fail. I added these specializations to allow them to work with the map_keys and map_values adaptors. Hopefully they will be of use to someone in the future or adapted to be included with the other MFC / ATL code. Would it be worthwhile to format this as a patch to the library? namespace boost { namespace range_detail { // CMap and CMapStringToString range iterators return CPair, // which has a key and value member. Other MFC range iterators // already return adapted std::pair objects. This allows usage // of the map_keys and map_values range adaptors with CMap // and CMapStringToString // specialization for CMap template<class KEY, class ARG_KEY, class VALUE, class ARG_VALUE> struct select_first<CMap<KEY, ARG_KEY, VALUE, ARG_VALUE>> { typedef BOOST_DEDUCED_TYPENAME CMap<KEY, ARG_KEY, VALUE, ARG_VALUE> map_type; typedef BOOST_DEDUCED_TYPENAME range_reference<const map_type>::type argument_type; typedef BOOST_DEDUCED_TYPENAME const KEY& result_type; result_type operator()( argument_type r ) const { return r.key; } }; template<class KEY, class ARG_KEY, class VALUE, class ARG_VALUE> struct select_second_mutable<CMap<KEY, ARG_KEY, VALUE, ARG_VALUE>> { typedef BOOST_DEDUCED_TYPENAME CMap<KEY, ARG_KEY, VALUE, ARG_VALUE> map_type; typedef BOOST_DEDUCED_TYPENAME range_reference<map_type>::type argument_type; typedef BOOST_DEDUCED_TYPENAME VALUE& result_type; result_type operator()( argument_type r ) const { return r.value; } }; template<class KEY, class ARG_KEY, class VALUE, class ARG_VALUE> struct select_second_const<CMap<KEY, ARG_KEY, VALUE, ARG_VALUE>> { typedef BOOST_DEDUCED_TYPENAME CMap<KEY, ARG_KEY, VALUE, ARG_VALUE> map_type; typedef BOOST_DEDUCED_TYPENAME range_reference<const map_type>::type argument_type; typedef BOOST_DEDUCED_TYPENAME const VALUE& result_type; result_type operator()( argument_type r ) const { return r.value; } }; // specialization for CMapStringToString template<> struct select_first<CMapStringToString> { typedef range_reference<const CMapStringToString>::type argument_type; typedef const CString& result_type; result_type operator()( argument_type r ) const { return r.key; } }; template<> struct select_second_mutable<CMapStringToString> { typedef range_reference<CMapStringToString>::type argument_type; typedef CString& result_type; result_type operator()( argument_type r ) const { return r.value; } }; template<> struct select_second_const<CMapStringToString> { typedef range_reference<const CMapStringToString>::type argument_type; typedef const CString& result_type; result_type operator()( argument_type r ) const { return r.value; } }; } } -- - Adam D. Walling

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