January 2013 - Boost-users - lists.preview.boost.org

boost::range vs && (rvalue ref)
by Neal Becker 11 Jan '13

11 Jan '13

Passing range by ref (&) is fine, but using (&&) results in and error. Any ideas? #include <boost/range.hpp> #include <vector> template<typename out_t> void F (out_t && o) { typedef typename boost::range_value<out_t>::type T; } void G() { std::vector<int> v; F (v); } usr/local/src/boost_1_52_0/boost/mpl/eval_if.hpp:60:31: error: no type named ‘type’ in ‘boost::mpl::eval_if_c<false, boost::range_const_iterator<std::vector<int>&>, boost::range_mutable_iterator<std::vector<int>&> >::f_ {aka struct boost::range_mutable_iterator<std::vector<int>&>}’ bug.cc: In instantiation of ‘void F(out_t&&) [with out_t = std::vector<int>&]’: bug.cc:12:7: required from here bug.cc:6:52: error: no type named ‘type’ in ‘struct boost::range_value<std::vector<int>&>’

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Re: [Boost-users] mixed 32bit and 64bit shared memory
by Dave Dyer 11 Jan '13

11 Jan '13

I see notes about boost supporting "customizing offset_ptr" to support shared memory where both 64 bit and 32 bit processes are sharing the memory, but I don't see a specific example of how to do that. It seems that "out of box" it doesn't work.

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Re: [Boost-users] mixed 32bit and 64bit shared memory
by Dave Dyer 11 Jan '13

11 Jan '13

I see notes about boost supporting "customizing offset_ptr" to support shared memory where both 64 bit and 32 bit processes are sharing the memory, but I don't see a specific example of how to do that. It seems that "out of box" it doesn't work.

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[1.53.0] Beta release candidates available
by Marshall Clow 10 Jan '13

10 Jan '13

Release candidate files for 1.53.0 beta 1 are available at http://boost.cowic.de/rc/ As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. This helps ensure the candidates build OK before we push them out to SourceForge. The files (and associated md5s) are: d5a45d0e08a14d5fb0965fe675d76ac6 *boost_1_53_0_beta1_rc1.tar.gz 89a6084458cd9f0e136c4b5292265461 *boost_1_53_0_beta1_rc1.tar.bz2 2a8897e04c59ccaf39189568f6966d60 *boost_1_53_0_beta1_rc1.zip 4cdf5a71d46e1115ca0c413f5b139a54 *boost_1_53_0_beta1_rc1.7z Thanks, --The release managers

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build without python
by Philipp Kraus 10 Jan '13

10 Jan '13

Hello, I try to build Boost with MPI on a system and I get errors, because Boost try to build python also. I run b2 and I build with the --with option the following libraries Performing configuration checks - gcc visibility : yes - long double support : yes - has_icu builds : no Component configuration: - chrono : not building - context : not building - date_time : building - exception : building - filesystem : building - graph : not building - graph_parallel : not building - iostreams : building - locale : not building - math : building - mpi : building - program_options : building - python : not building - random : building - regex : building - serialization : building - signals : not building - system : building - test : not building - thread : building - timer : not building - wave : not building The b2 command is: --with-exception --with-math --with-system --with-iostreams --layout=system link=shared runtime-link=shared threading=multi variant=release install --prefix=../build_release/boost/1.52.0 --with-regex --with-random --with-thread --with-date_time --with-program_options --with-filesystem --with-mpi --with-serialization The build process breaks with the error eg: ...failed gcc.compile.c++ bin.v2/libs/python/build/gcc-4.6/release/threading-multi/long.o... gcc.compile.c++ bin.v2/libs/python/build/gcc-4.6/release/threading-multi/dict.o In file included from ./boost/python/detail/prefix.hpp:13:0, from ./boost/python/dict.hpp:8, from libs/python/src/dict.cpp:4: ./boost/python/detail/wrap_python.hpp:75:24: fatal error: patchlevel.h: No such file or directory compilation terminated. If I mix --with and --without option on the b2 command I get the error: error: both --with-<library> and --without-<library> specified How can I disable any Python builds? Thanks Phil

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build without python
by Philipp Kraus 10 Jan '13

10 Jan '13

Hello, I try to build Boost with MPI on a system and I get errors, because Boost try to build python also. I run b2 and I build with the --with option the following libraries Performing configuration checks - gcc visibility : yes - long double support : yes - has_icu builds : no Component configuration: - chrono : not building - context : not building - date_time : building - exception : building - filesystem : building - graph : not building - graph_parallel : not building - iostreams : building - locale : not building - math : building - mpi : building - program_options : building - python : not building - random : building - regex : building - serialization : building - signals : not building - system : building - test : not building - thread : building - timer : not building - wave : not building The b2 command is: --with-exception --with-math --with-system --with-iostreams --layout=system link=shared runtime-link=shared threading=multi variant=release install --prefix=../build_release/boost/1.52.0 --with-regex --with-random --with-thread --with-date_time --with-program_options --with-filesystem --with-mpi --with-serialization The build process breaks with the error eg: ...failed gcc.compile.c++ bin.v2/libs/python/build/gcc-4.6/release/threading-multi/long.o... gcc.compile.c++ bin.v2/libs/python/build/gcc-4.6/release/threading-multi/dict.o In file included from ./boost/python/detail/prefix.hpp:13:0, from ./boost/python/dict.hpp:8, from libs/python/src/dict.cpp:4: ./boost/python/detail/wrap_python.hpp:75:24: fatal error: patchlevel.h: No such file or directory compilation terminated. If I mix --with and --without option on the b2 command I get the error: error: both --with-<library> and --without-<library> specified How can I disable any Python builds? Thanks Phil

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Building boost with custom gcc/g++
by arjun 10 Jan '13

10 Jan '13

Hi, I have issues in getting boost to build with a custom gcc installation in a separate folder, with default gcc in /usr/bin/. Describing the problem, and issues I am facing below. I would love to have a foolproof and right way to do this. I hope I can get some help here. Building boost with a custom compiler : Problem : 1. I have gcc/g++ in /usr/bin, and I have gcc 4.7.2 in /shared/tools/rtf/bin/gcc & /shared/tools/rtf/bin/g++ 2. I want to compile boost libraries using gcc 4.7.2 ONLY. Solutions : 1. If I export PATH as /shared/tools/rtf/bin:$PATH, so that "which gcc" picks the 4.7.2 one, then I run ./bootstrap.sh and ./b2 install, is that a correct way to do it? 2. Alternatively, would I have to change some .jam files like user-config.jam to point out gcc with using gcc : gcc-4.4 : /shared/tools/... gcc and then compile using Boost.build? Is this the recommended way? Issues/Confusions : 1. If I try to build using Boost.build way I first go to the directory tools/build/v2. Now 1st step to bootstrap, how to bootstrap it with /shared/tools/...gcc compiler? The only way I saw for that was to do like CC=/shared/tools/..gcc ./bootstrap.sh --with-toolset=cc as this actually picks from CC environment variable. Is this correct? 2. The subsequent step ./b2 install --prefix=INSTALL_PATH to build Boost.build fails saying cc.jam not present. How to get that jam file to be present? Should that be created manually? 3. I had also changed user-config.jam to have gcc-4.7 (using gcc : 4.7 : /shared/tools/..gcc). CC=/shared/tools/..gcc ./bootstrap.sh --with-toolset=cc toolset=gcc-4.7 Is this used during bootstrap.sh step? Or only when we give the actual boost build (running b2) 4. Another issue was when I run the bootstrap.sh inside tools/build/v2 (to get Boost.build built), If I give a --with-toolset option, I get the b2 and bjam executables in the current directory. If I do not give a with-toolset option, it automatically defaults to cc, in which case the b2,bjam are inside engine/bin.linux86_64 folder. Not able to understand this. Thanks, Arjun

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Pushing iterators to far?
by Simon Knapp 10 Jan '13

10 Jan '13

Hi All, I'm trying to do some slightly hooky stuff with the iterators library and cannot get the following code to compile. When the second last line of main is uncommented ("ZIter iter(b);"), compilation fails. The error mesages suggest this is a problem with determining the appropriate traversal category of "ZIter". Can anyone advise if this is problem with my code, a bug, am I asking too much of the library, ...? Cheers, Simon Knapp. compiler: Visual Studio 2008 - version 9.0.30729.1 SP //---------------------------------------------------------------------------------------------------------------------------- // begin iterator_tests.cpp //---------------------------------------------------------------------------------------------------------------------------- #include <vector> #include <boost/iterator/filter_iterator.hpp> #include <boost/iterator/zip_iterator.hpp> #include <boost/tuple/tuple.hpp> typedef std::vector<long long> LLGrid; typedef std::vector<float> FloatGrid; typedef LLGrid::const_iterator LLGridIter; typedef FloatGrid::const_iterator FloatGridIter; typedef boost::tuples::tuple<LLGridIter, FloatGridIter> IDAndAreaTuple; typedef boost::zip_iterator<IDAndAreaTuple> IDAndAreaIterator; typedef std::iterator_traits<IDAndAreaIterator>::reference IDAndAreaRef; struct Fnctr { bool operator()(const IDAndAreaRef ref) const { return true; } }; typedef boost::filter_iterator<Fnctr, IDAndAreaIterator> FIter; typedef boost::tuples::tuple<FloatGridIter, FIter> ZIterTuple; typedef boost::zip_iterator<ZIterTuple> ZIter; static ZIterTuple makeZIterTuple( Fnctr const& fnctr, LLGridIter const& beginIdGrid, LLGridIter const& endIdGrid, FloatGridIter const& beginAreaGrid, FloatGridIter const& endAreaGrid, FloatGridIter const& gtgdIter ) { return boost::make_tuple( gtgdIter, boost::make_filter_iterator( fnctr, boost::make_zip_iterator(boost::make_tuple(beginIdGrid, beginAreaGrid)), boost::make_zip_iterator(boost::make_tuple(endIdGrid, endAreaGrid)) ) ); } int main(int argc, char* argv[]) { FloatGrid areaMask, regionStat; LLGrid regionMask; ZIterTuple b(makeZIterTuple(Fnctr(), regionMask.begin(), regionMask.end(), areaMask.begin(), areaMask.end(), regionStat.begin())); //ZIter iter(b); return 0; } //---------------------------------------------------------------------------------------------------------------------------- // end iterator_tests.cpp //----------------------------------------------------------------------------------------------------------------------------

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[units]
by geocentrix 10 Jan '13

10 Jan '13

I am attempting to replace my own Quantity class with boost::units. One thing that is easy in my existing code is to convert a quantity from any unit of pressure into a specific unit, e.g. GPa (gigapascals), using a function ConvertedTo(). For example: Pressure converted_value = existing_value.ConvertedTo(GPa); How do you do this with boost:units.? I have the following things defined: typedef boost::units::quantity<boost::units::si::pressure> Pressure; static const Pressure Pa = 1.0 * boost::units::si::pascals; static const Pressure GPa = 1e9 * Pa; Pressure value(1.0^9 * Pa); How do I display value in GPa? I am missing something very simple and wondered if someone could advise, please? Thanks in advance. Andrew -- View this message in context: http://boost.2283326.n4.nabble.com/units-tp4641179.html Sent from the Boost - Users mailing list archive at Nabble.com.

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[locale] how to sort utf8 std::string?
by Frédéric Bron 09 Jan '13

09 Jan '13

I read std::string from a file encoded in UTF-8. I would like to sort the strings. I think I have to first convert them to wide characters and then sort the resulting output. I have tried to do that with boost::local::conv::to_utf(utf8string, "UTF-8"); But it seems that all non ASCII characters are replaced by the question mark. Here is my program: #include <iostream> #include <fstream> #include <string> #include <boost/locale/encoding.hpp> int main(int argc, char **argv) { if (argc<2) return 0; std::ifstream is(argv[1], std::ios::binary); while (is) { std::string line; std::getline(is, line); if (not line.empty()) { try { std::wstring ws=boost::locale::conv::to_utf<wchar_t>(line, "UTF-8", boost::locale::conv::stop); std::wcout<<ws; } catch (...) { std::cout<<"exception\n"; } } } is.close(); return 0; } Frédéric

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[astar search] Computation time for large graph
by Yann-Hervé Hellouvry 09 Jan '13

09 Jan '13

Hi, I try to use the "astar-cities" example but for graph of about 10000 nodes and edges (which are weighted) in order to find the fastest path between two random nodes... and I want to do it several times. I encountered very large computation time : about 4 min to perform 100 searches. Is it supposed to be slow for large graph? My machine is not very powerful but I think I've missed something...Is there ways to optimize? Can it be a problem from the weighted edges or from the heuristic distance ? my astar_search function call is : boost::astar_search(m_g, vertexStart, heuristicDistance, boost::predecessor_map(&p[0]) .distance_map(&d[0]) .visitor(astarVisitor) ); with m_g my graph which is a: typedef boost::adjacency_list<boost::listS, boost::vecS, boost::bidirectionalS, VertexProperties, boost::property<boost::edge_weight_t, float> > my_graph; heuristicDistance : same as the example (a simple euclidian distance) astarVisitor : same as the example any help is appreciated ! Thanks, Happy new year btw, YH

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[Locale] as::ftime formatting
by Szymon Gatner 09 Jan '13

09 Jan '13

Hey, docs say: "There is a list of supported strftime flags by ICU backend:". I didn't build my boost/locale with ICU but still tried what happens when I try as::ftime("%A") an to my surprise I got correctly localized day of the week. My questions are: is it correct that it works without ICU? will it work on other machines (Win 32 bit)? What is the encoding of output string? I am seeing it correctly displayed as utf-8 but would like to know what is happening. Can I ensure utf-8 output? My test code: using namespace boost::locale; generator gen; locale loc=gen(""); std::ostringstream ostr; ostr.imbue(loc); ostr << as::datetime << as::ftime("%A") << info.time; std::String timeStr = ostr.str(); Cheers, Simon -- Szymon Gatner The Lordz Games Studio www.thelordzgamesstudio.com

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boost serialization: can't deserialize pointer to abstract base class where derived classes overload load_construct_data
by Rebecca Lehman 09 Jan '13

09 Jan '13

I have some pointers to instances of an abstract base class. Some of the derived classes have no default constructors. I can serialize instances of these derived classes by overloading load_construct_data and save_construct_data, but I always get segmentation faults when I try to serialize the base class pointers. Saving works fine, and loading will correctly load the instances of the derived classes, but it segfaults before initializing the pointers. It doesn't seem to matter whether I overload the load_construct_data and save_construct_data of the base class, or how I register my classes and the base/derived relationship, or whether the pointers are ordinary pointers or boost::shared_ptrs. (The details of the segfault messages vary, but it always segfaults). Does anyone have an example of how to serialize such pointers? Here's a trivial example of what I'm trying to do: class Base { Base() {} public: virtual int Apply()=0 const; protected: friend class boost::serialization::access; template<class Archive> void serialize(Archive &ar, const unsigned int version){ } }; BOOST_ASSUME_ABSTRACT(Base); class D1 { public: D1( int der_input): der_int(der_input){} int Apply() const { return der_int; } protected: const int & der_int; friend class boost::serialization::access; template<class Archive> void serialize(Archive &ar, const unsigned int version){ ar & boost::serialization::base_object<Base>(*this); // or boost::serialization::void_cast_register<D1, Base>( // static_cast<D1 *>(NULL), // static_cast<Base *>(NULL) // ) } }; BOOST_CLASS_EXPORT_GUID(D1, "D1"); class D2 { public: D2( int der_input): der_int(der_input){} int Apply() const { return 2*der_int; } protected: const int der_int; friend class boost::serialization::access; template<class Archive> void serialize(Archive &ar, const unsigned int version){ ar & boost::serialization::base_object<base_class_of_T>(*this); // save/load class member variables } }; BOOST_CLASS_EXPORT_GUID(D1, "D1"); namespace boost { namespace serialization { template<class Archive> inline void save_construct_data( Archive & ar, const D1* t, const unsigned int file_version ){ // save data required to construct instance ar << t->der_int; } template<class Archive> inline void load_construct_data( Archive & ar, D1 * t, const unsigned int file_version ){ // retrieve data from archive required to construct new instance int attribute; ar >> attribute; // invoke inplace constructor to initialize instance of my_class ::new(t)D1(attribute); } template<class Archive> inline void save_construct_data( Archive & ar, const D2* t, const unsigned int file_version ){ // save data required to construct instance ar << t->der_int; } template<class Archive> inline void load_construct_data( Archive & ar, D2 * t, const unsigned int file_version ){ // retrieve data from archive required to construct new instance int attribute; ar >> attribute; // invoke inplace constructor to initialize instance of my_class ::new(t)D2(attribute); } }} main(){ ... ar.template register_type<D1>(); ar.template register_type<D2>(); std::vector<Base *> b; ... ar & b; }

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Boost.MSM: Executable size
by RaRi 08 Jan '13

08 Jan '13

Hi all, I'm using boost.MSM for a productive embedded system. My concern is, that my compiler produces a executable size of all most 2MB for a state machine consisting of 4 sub-machine and nearly 40 transition for the complete state machine, but with no action and guard code. My compilation system is as follows: - eclipse juno - mingw 4.7.0 - Compiler settings for the release of the binary are: "-O3 -Wall -c -fmessage-length=0" Is this a good size or should I be worried about this nearly 2 MB for the release executable? I'm asking as like stated in http://www.boost.org/doc/libs/1_52_0/libs/msm/doc/HTML/ch04s02.html <http://www.boost.org/doc/libs/1_52_0/libs/msm/doc/HTML/ch04s02.html> the executable size for a good sized state machine could reach a size of almost 600kB, and my state machine is still not finished (50 % more code has to be added for further submachine...) Using the "-Os" produces a executable size which is almost 20% smaller as with the "-O3". In case I compile the state machine with the default debug level (-g) the binary is allmost 35MB big.... The compilation takes around 1m:30sec ( using the *favor_compile_time* policy)... Best regard, RaRi -- View this message in context: http://boost.2283326.n4.nabble.com/Boost-MSM-Executable-size-tp4641132.html Sent from the Boost - Users mailing list archive at Nabble.com.

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Problem with installation
by Evan Driscoll 08 Jan '13

08 Jan '13

Hi, I'm having problems with the installation procedure. I'm using the 1.53 beta. I have run the following: ./bootstrap.sh --prefix=/unsup/boost-1.53.0/beta/common --exec-prefix=/unsup/boost-1.53.0/beta/amd64_rhel6 ./b2 --prefix=/unsup/boost-1.53.0/beta/common --exec-prefix=/unsup/boost-1.53.0/beta/amd64_rhel6 -j12 ./b2 --prefix=/unsup/boost-1.53.0/beta/common --exec-prefix=/unsup/boost-1.53.0/beta/amd64_rhel6 -j12 install however it is ignoring my --exec-prefix and installing everything to /unsup/boost-1.53.0/beta/common. I actually haven't really used --exec-prefix before I think, and have just manually moved stuff around post-installation instead. But I figured I'd try to do it "right" this time and actually use the tools I've been given. :-) What am I doing wrong? [Disclaimer: I made a typo originally and ran both bootstrap.sh and b2 with both --prefix and --exec-prefix set to ..../common. I did run './b2 clean' after that though.] Evan

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How to use geometry::within with a polygon that encompasses a pole
by Cameron Sabol 08 Jan '13

08 Jan '13

Hi, I'm have an issue with polygons from the geometry library using the spherical_equatorial coordinates when the polygon is meant to wrap a pole. e.g. namespace bg = boost::geometry; typedef bg::model::point < double, 2, bg::cs::spherical_equatorial<bg::degree> > LonLatPoint; bg::model::polygon < LonLatPoint> northPoleBoundary; double lon = -180; while (lon <= 180) { bg::append(northPoleBoundary, LonLatPoint(lon, 88)); lon += 5; } LonLatPoint northPole(90, 0); bool isInNorthPole = bg::within(northPole, northPoleBoundary); This code is giving me isInNorthPole == false. Am I constructing my polygon incorrectly? Is this a bug? Or is this behavior simply not implemented? Thanks for your help!

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[MultiArray, Intrusive] Instantiating a multi_array of intrusive lists as a class member
by Jiri Vyskocil 08 Jan '13

08 Jan '13

Hello, I want to try Boost Intrusive list instead of std::list in a performance and memory critical part of code. I have a Domain object, which contains a boost::multi_array of cells. each cell contains a list of particles std::list<Particle>. This sample code works as expected (std::list): #include <list> #include <iostream> #include <boost/multi_array.hpp> struct Particle { unsigned number; Particle(unsigned n){ number = n; } }; typedef std::list<Particle> ParticleList; typedef boost::multi_array<ParticleList, 3> ParticleArray; class Domain { public: ParticleArray particles; Domain(int x, int y, int z) : particles(boost::extents[x][y][z]) { } }; int main(){ Domain* dom = new Domain(10,10,10); dom->particles[5][5][5].push_back(Particle(1)); std::cout << dom->particles[5][5][5].front().number << std::endl; return 0; } When I try to swap the std::list for an intrusive list, I get a compile error on Domain instantiation. Minimal code leading to the error: #include <boost/intrusive/list.hpp> #include <boost/multi_array.hpp> typedef boost::intrusive::list_base_hook<> BaseHook; struct Particle : BaseHook { unsigned number; }; typedef boost::intrusive::list<Particle> ParticleList; typedef boost::multi_array<ParticleList, 3> ParticleArray; class Domain { public: ParticleArray particles; Domain(int x, int y, int z) : particles(boost::extents[x][y][z]) { } }; int main(){ Domain* dom = new Domain(10,10,10); return 0; } When I try to compile the above code, gcc tells me: In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/4.6.3/include/g++-v4/bits/stl_tempbuf.h:61:0, from /usr/lib/gcc/x86_64-pc-linux-gnu/4.6.3/include/g++-v4/bits/stl_algo.h:64, from /usr/lib/gcc/x86_64-pc-linux-gnu/4.6.3/include/g++-v4/algorithm:63, from /usr/include/boost/move/move.hpp:37, from /usr/include/boost/intrusive/detail/has_member_function_callable_with.hpp:22, from /usr/include/boost/intrusive/detail/memory_util.hpp:112, from /usr/include/boost/intrusive/pointer_traits.hpp:26, from /usr/include/boost/intrusive/detail/utilities.hpp:17, from /usr/include/boost/intrusive/list_hook.hpp:19, from /usr/include/boost/intrusive/list.hpp:20, from intrusive.cc:1: /usr/lib/gcc/x86_64-pc-linux-gnu/4.6.3/include/g++-v4/bits/stl_construct.h: In function ‘void std::_Construct(_T1*, const _T2&) [with _T1 = boost::intrusive::list<Particle>, _T2 = boost::intrusive::list<Particle>]’: /usr/lib/gcc/x86_64-pc-linux-gnu/4.6.3/include/g++-v4/bits/stl_uninitialized.h:189:3: instantiated from ‘static void std::__uninitialized_fill_n<_TrivialValueType>::__uninit_fill_n(_ForwardIterator, _Size, const _Tp&) [with _ForwardIterator = boost::intrusive::list<Particle>*, _Size = long unsigned int, _Tp = boost::intrusive::list<Particle>, bool _TrivialValueType = false]’ /usr/lib/gcc/x86_64-pc-linux-gnu/4.6.3/include/g++-v4/bits/stl_uninitialized.h:225:7: instantiated from ‘void std::uninitialized_fill_n(_ForwardIterator, _Size, const _Tp&) [with _ForwardIterator = boost::intrusive::list<Particle>*, _Size = long unsigned int, _Tp = boost::intrusive::list<Particle>]’ /usr/include/boost/multi_array.hpp:477:5: instantiated from ‘void boost::multi_array<T, NumDims, Allocator>::allocate_space() [with T = boost::intrusive::list<Particle>, long unsigned int NumDims = 3ul, Allocator = std::allocator<boost::intrusive::list<Particle> >]’ /usr/include/boost/multi_array.hpp:186:5: instantiated from ‘boost::multi_array<T, NumDims, Allocator>::multi_array(const boost::detail::multi_array::extent_gen<NumDims>&) [with T = boost::intrusive::list<Particle>, long unsigned int NumDims = 3ul, Allocator = std::allocator<boost::intrusive::list<Particle> >]’ intrusive.cc:18:49: instantiated from here /usr/lib/gcc/x86_64-pc-linux-gnu/4.6.3/include/g++-v4/bits/stl_construct.h:84:7: error: passing ‘const boost::intrusive::list<Particle>’ as ‘this’ argument of ‘boost::intrusive::list<T, O1, O2, O3>::operator boost::rv<boost::intrusive::list<T, O1, O2, O3> >&() [with T = Particle, O1 = boost::intrusive::none, O2 = boost::intrusive::none, O3 = boost::intrusive::none]’ discards qualifiers [-fpermissive] This is just a minimal sample code to trigger an error. In the actual code, both Domain and Particle objects are more complicated. The last line of error output is sligtly different: /usr/lib/gcc/x86_64-pc-linux-gnu/4.6.3/include/g++-v4/bits/stl_construct.h:84:7: error: no matching function for call to ‘boost::intrusive::list<Particle>::list(const boost::intrusive::list<Particle>&)’ followed by a note with a list of candidate functions. If I define the multi_array so that it contains pointers to ParticleArray, i.e.: typedef boost::multi_array<ParticleList*, 3> ParticleArray; there seems to be no benefit over the std::list approach, since I have to hold the additional pointer. In a test simulation, this variant eats about 10% more RAM, which is of concern in our situation. Any ideas how to replace std::list with boost::intrusive::list in a multi_array in a way which wouldn't consume more memory than the std::list approach? (I would want to see if it also brings the much needed performance benefit) Jiri Vyskocil

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[Iterator] filter_iterator over greedy?
by Robert Jones 07 Jan '13

07 Jan '13

Hi Folks, Somewhat to my surprise this code, simply creating a filter_iterator, evaluates the predicate until an element satisfying the predicate is found. This seems wrong to me. Shouldn't evaluation of the predicate be delayed until the filter_iterator is dereferenced? Thx, Rob. #include <iostream> #include <boost/range.hpp> #include <boost/iterator/filter_iterator.hpp> bool predicate( int i ) { std::cout << "predicate(" << i << ")" << std::endl; return true; } int main( ) { int array[] = { 0, 1 }; boost::make_filter_iterator( predicate, boost::begin( array ), boost::end( array ) ); } > [Run] predicate(0) >

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Using OvenToBoost 'taken'.
by Robert Jones 07 Jan '13

07 Jan '13

Hi Folks This question is about using the OvenToBoost port, not currently part of Boost, but likely to be soon, I understand. The code below evaluates the predicate for the first and second elements of the array. The evaluation of the second element seems to me to be unnecessary and wrong, since the 'taken' adaptor knows the range is ended after the first element is taken. Thoughts? Thx, Rob. #include <boost/range/adaptor/filtered.hpp> #include <boost/range/adaptor/taken.hpp> #include <boost/range/algorithm/for_each.hpp> #include <iostream> bool predicate( int i ) { std::cout << "predicate(" << i << ")" << std::endl; return true; } void doNothing( int ) { } int main( ) { int array[ ] = { 0, 1, 2, 3, 4, 5 }; for_each( array | boost::adaptors::filtered( predicate ) | boost::adaptors::taken( 1 ), doNothing ); }

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[Property Tree] Complexity of find and get methods
by Elizabeta 07 Jan '13

07 Jan '13

Hi I want to know the complexity of boost property tree find and get methods. I tried the following link http://www.boost.org/doc/libs/1_41_0/doc/html/boost/property_tree/basic_ptr… but it seems that the complexity is not specified. Also can find function accept string paths or it just finds immediate childs? Thank you

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Problem finally found!
by Gonzalo Garramuno 06 Jan '13

06 Jan '13

My problem was that acceptor_ was called twice and two sessions were created. The first session was used properly while the second session missed the socket setup. class server { public: server(boost::asio::io_service& io_service, const tcp::endpoint& listen_endpoint, mrv::ViewerUI* v) : io_service_(io_service), acceptor_(io_service, listen_endpoint), ui_( v ) { start_accept(); } void start_accept() { tcp_session_ptr new_session( boost::make_shared<tcp_session>( boost::ref( io_service_ ), boost::ref(ui_) ) ); std::cerr << "******** TCP SESSION " << new_session << std::endl; acceptor_.async_accept(new_session->socket(), boost::bind(&server::handle_accept, this, new_session, _1)); } void handle_accept(tcp_session_ptr session, const boost::system::error_code& ec) { if (!ec) { session->start(); } start_accept(); // BAD } Changed to: void handle_accept(tcp_session_ptr session, const boost::system::error_code& ec) { if (!ec) { session->start(); } else { start_accept(); } } I still don't know why this is so and the problem is not fully resolved, as only the server change in the timeline works only once, but at least the server now works.

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[interprocess] (OS X) waiting on condition variable = CPU 100% + fans running loud
by Francisco Lopes 06 Jan '13

06 Jan '13

Hi, I was implementing a kind of server using shared memory. The server should keep idle, waiting for a request and I do this by waiting on a condition variable, of course. I then noticed my fans running high when I let the server waiting a little longer while testing and discovered this happens simply because of some busy loop implementation for condition waiting. Is there any reason for that? Given the interprocess library age, no way for implementing a non-busy interprocess condition variable waiting is available? https://svn.boost.org/trac/boost/ticket/6108 Regards, Francisco Lopes

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MPL vs. Proto for EDSL dev?
by Chris Russell 05 Jan '13

05 Jan '13

Hello, all. I'm reading the MPL book (again) and tinkering with some ideas for a new library for building complex FSM hierarchies [1]. I've got a minimal runtime library written that codifies the important concepts but now want to try to make it a native C++ EDSL and am wondering if it makes more sense to concentrate on MPL, Proto (or both)? For pure education on the subject of C++ template metaprogramming the MPL and the amazing Abrahams/Gurtovoy book seems like the right starting place but would appreciate any advice you folks are willing to share with me. Thanks, Chris [1] I am aware of other FSM libs (e.g. StateChart, MSM) and likely some of what I'm planning is redundant. That's okay: my goal is to gain deeper understanding of C++ template metaprogramming by working through a non-trivial problem.

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boost-mpi assertion during recv fails
by Kyle Joseph Berger 04 Jan '13

04 Jan '13

Hello, I am using boost-mpi and I am getting an error that I am having a hard time figuring out. I am using a recv call and an assertion in the boost code fails: void boost::mpi::binary_buffer_iprimitive::load_impl(void *, int): Assertion `position+l<=static_cast<int>(buffer_.size())' This is from the file binary_bffer_iprimitive.hpp located in boost/mpi/detail/. This does not occur the first time I am receiving so I know it's not a general error with every send/recv call I make. I think this assertion is checking whether the buffer is large enough to accommodate the data being received, but I'm not even sure about that. If that is the case, what could cause the buffer to not be large enough? Shouldn't that be taken care of by the underlying boost? Thanks, Kyle

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[Locale] Security bug announcement - UTF-8 validation
by Artyom Beilis 04 Jan '13

04 Jan '13

Hello, Boost.Locale library in Boost 1.48 to 1.52 including has a security flow. boost::locale::utf::utf_traits accepted some invalid UTF-8 sequences. Applications that used these functions for UTF-8 input validation could expose themself to security threats as invalid UTF-8 sequece would be considered as valid. This bug is fixed in upcoming Boost 1.53. For more details see: https://svn.boost.org/trac/boost/ticket/7743 Users who can't upgrade to the latest versions may apply the following patch to fix the problem. http://cppcms.com/files/locale/boost_locale_utf.patch Regards, Artyom Beilis -------------- CppCMS - C++ Web Framework: http://cppcms.com/ CppDB - C++ SQL Connectivity: http://cppcms.com/sql/cppdb/

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