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

[Sandbox - endian] Why is endian still in sandbox?
by Nathaniel J Fries 07 Oct '12

07 Oct '12

A fairly novel (at least when put up against more intricate labours like asio, filesystem, and their like) project which appears to be finished and would be a very useful companion to existing libraries sits in the sandbox. Is there a reason for this?

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[Range] insert algorithm fails if target is a map
by Robert Jones 11 Sep '12

11 Sep '12

The title says it all really. The failure occurs because the insert algorithm expects the container to provide a 3-arg insert of the form container.insert( position, begin, end ); whereas map's, multimap's and set's insert method only takes two arguments... map.insert( begin, end ); Is this limitation by design? It would be easy to provide specialisations for maps, mmaps and sets, but that would not be a completely general solution. - Rob.

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[Graph] compilation error under Windows but not under Linux
by Gaël de Chalendar 29 Aug '12

29 Aug '12

Hello, I have a compilation error under Windows (Visual C++ 2008) with a code that works well under Linux (gcc 4.6.1 and before). The compilation error is: =========== /FsaAccess16.tcc(833) : error C2784: 'std::pair<graph_traits<G>::in_edge_iterator,graph_traits<G>::in_edge_iterator> boost::in_edges(graph_traits<G>::vertex_descriptor,const boost::subgraph<Graph> &)'ÿ: impossible de d‚duire l'argument modŠle pour 'const boost::subgraph<Graph> &' … partir de 'FrCeaLic2m::Common::FsaAccess::selected_graph_types16::spareGraphType' C:\PROGRA~1\boost\BOOST_~1\boost/graph/subgraph.hpp(432)ÿ: voir la d‚claration de 'boost::in_edges' Z: \Projets\MoteurMultimedia\mm_common\src\common/FsaAccess/FsaAccess16.tcc(778)ÿ: lors de la compilation de la fonction membre '<Inconnu>' de la classe <Inconnu> z: \projets\moteurmultimedia\mm_common\src\common\fsaaccess\FsaAccessReader16.h(118)ÿ: voir la r‚f‚rence … l'instanciation de la classe modŠle 'FrCeaLic2m::Common::FsaAccess::FsaAccess16<graphType>' en cours de compilation with [ graphType=FrCeaLic2m::Common::FsaAccess::selected_graph_types16::spareGraphType ] z: \projets\moteurmultimedia\mm_common\src\common\fsaaccess\FsaAccessSpare16.h(35)ÿ: voir la r‚f‚rence … l'instanciation de la classe modŠle 'FrCeaLic2m::Common::FsaAccess::FsaAccessReader16<graphType>' en cours de compilation with [ graphType=FrCeaLic2m::Common::FsaAccess::selected_graph_types16::spareGraphType ] =========== The line that does not compile is boost::tie(iei,ie_end) = boost::in_edges(commonTarget,m_graph); The function being compiled is declared like that: template <typename graphType > std::pair< const typename boost::graph_traits<graphType>::vertex_descriptor, bool > FsaAccess16<graphType>::findEquivalentInRegister( dicoVertexType tempState ){ ... And here graphType, the type of m_graph is spareGraphType defined by: struct selected_graph_types16 { ... typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, dicoVertexCountProperty> spareGraphType; ... This is a cmake based project that I compile using qtcreator. I'm a Linux developer and I'm a little bit lost with VC outputs and tools under Windows... Regards, Gaêl -- Gael de Chalendar CEA LIST Centre de Fontenay-aux-Roses Laboratoire Vision et Ingénierie des Contenus (Vision and Content Engineering Laboratory) Bat. 38-2 ; 18, rue du Panorama ; BP 6 92265 Fontenay aux Roses Cedex ; France Tél.:01.46.54.80.18 ; Fax.:01.46.54.75.80 Email : Gael.D.O.T.de-Chalendar.A(a)T.cea.D.O.T.fr

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Re: [Boost-users] asio HTTP Server 3 example memory leak
by admin＠thefireflyproject.us 25 Aug '12

25 Aug '12

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[vector, PropertyGraph] Problem declaring a class member of the "vector<int>" type
by Alex Sadovsky 13 Jun '12

13 Jun '12

Hello everyone, > >I am trying to declare, in a header file, a class that has a member of type "vector<double>" (the code is included below). The compiler complains that I haven't included the appropriate namespace (the error message reads, "ISO C++ forbids declaration of ‘vector’ with no type"), and I understand that it is looking for this: > >using namespace boost::numeric::ublas; > >However, I tried putting it in the header file in various places (haven't programmed in C++ in 10 years and couldn't find any online documentation to clarify this specific situation), and still no luck. I am definitely doing something wrong, but cannot reason out the error, as it probably has to do with the specific syntax conventions. Any help is appreciated! > >Thanks, >-Al > >P.S. Code in header file: > >////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// >// File "airspace-graph-rectilinear-edges.h" >typedef char* string; >const int PHYSICAL_SPACE_DIMENSION = 2; >// Information needed about a waypoint used in an airspace: name and physical position >class WaypointConcept{ > private: > using namespace boost::numeric::ublas; > string waypoint_name; > vector<double> waypoint_position_xyh(PHYSICAL_SPACE_DIMENSION); > public: > string GetWaypointName(); > vector<double> GetWaypointPosition(); >} > >class AirspaceGraphConcept PropertyGraphConcept<class Graph, class WaypointConcept, class vertex_index_t>; >typedef Vertex* GraphPathType; >typedef string FlightIDType; >typedef boost::unordered_map<std::FlightIDType, GraphPathType> FlightIDToPathAssignmentType; >////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// > >Code in the .cpp file (which includes the above header file) I am trying to compile: >////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// >#include <boost/lambda/lambda.hpp> >#include <iostream> >#include <iterator> >#include <algorithm> >#include <boost/numeric/ublas/io.hpp> >#include <boost/numeric/ublas/vector.hpp> >#include "airspace-graph-rectilinear-edges.h" > >int main() >{ > using namespace boost::numeric::ublas; > > vector<double> v(3); > for (unsigned i = 0; i < v.size(); ++ i) > v (i) = 2.01*double(i); > > std::cout << v << std::endl; >} >////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// > > > > > > > > > > > > > > > >

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[property_tree] number of sections in an inifile
by Sean Farrow 13 Jun '12

13 Jun '12

Hi: If I have defined: boost::property_tree::ptree IniTree; What is the correct way to determine how many sections there are in an ini file. Should I use count, max_size, m_children or size? Any help appreciated. Cheers Sean.

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accumulator operations
by Olaf Peter 04 Jun '12

04 Jun '12

Hi, I like to collects some stats. There are several data slices where I can partially/separated collect them (each of them). Finaly I like to combine these stats to a single one to get summarized informations. How to? May this work: accumulator_set<..> acc1; accumulator_set<..> acc2; ... accumulator_set<..> acc_all; ... acc1(42); ... acc_all += acc1; ... acc_all += acc2; Because did not found informations about. The same problem woulde be probably for a threaded implementation too. Thanks, Olaf

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[multi_array] operator= requires resize - why?
by Markus Werle 04 Jun '12

04 Jun '12

Hi! IMHO the behaviour of operator= for multi_array is a little bit broken. A lot of preconditions required: template <typename ConstMultiArray> multi_array_ref& operator=(const ConstMultiArray& other) { [...] // make sure the dimensions agree assert(other.num_dimensions() == this->num_dimensions()); assert(std::equal(other.shape(),other.shape()+this->num_dimensions(), this->shape())); Besides the fact that I get mad about asserts instead of exceptions (please change this to a way users may choose) why do we have such an odd behaviour here? >From page 1, line 3 of the docs I cite: "The interface design is in line with the precedent set by the C++ Standard Library containers" - this is not true for operator=, since std::<container>::operator= works fine for me all the time _without_ any resize. Could we please change the behaviour of multi_array::operator= to take care of resize where in need to? IMHO operator= should result in a true copy ignoring previous state. Markus

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offlist - Re: [iterator] Problems with iterator_facade and const-qualification
by Neil Groves 24 May '12

24 May '12

On Sat, May 7, 2011 at 5:52 PM, Dave Abrahams <dave(a)boostpro.com> wrote: > On Fri, May 6, 2011 at 1:51 PM, Evan Driscoll <driscoll(a)cs.wisc.edu> > wrote: > > On 05/06/2011 11:59 AM, Jeff Flinn wrote: > >> > >> You might google any_iterator, and see how other authors have addressed > >> similar problems. > > > > Great! I tried to find someone who had done something similar, figuring I > > couldn't have been the first, but all the search terms I tried were too > > generic. > > > > Thanks, > > Evan > > You can find one in the ASL that's built on iterator_facade. > http://stlab.adobe.com/classadobe_1_1any__iterator.html > > The underlying Boost.Range implementation implements an any_iterator that I believe to be similar to the one in ASL in terms of functionality. I believe that the small-buffer optimization implementation is superior to forcing the definition of a closed-set of possible type as suggested in a TODO within the ASL documentation. During my performance testing I had considerably superior performance than the ASL implementation. I wondered if you disliked my implementation, or had any feedback. Additionally I wondered what you thought about moving the Boost.Range internal any_iterator implementation into Boost.Iterator. I can't honestly imagine a good use-case for using any_iterator in preference to any_range, hence I haven't suggested this previously. This could easily be due to my lack of imagination! Can you think of a time when using an any_iterator on any interface would be superior to using an any_range? Your opinions and guidance would be much appreciated. HTH, > > -- > Dave Abrahams > BoostPro Computing > http://www.boostpro.com Regards, Neil Groves

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C++ Now! Conference Program Highlights C++11
by Jon Kalb 29 Apr '12

29 Apr '12

C++ Now! (formerly BoostCon) is pleased to announce its 2012 program with 35+ inspiring C++ practitioners delivering more than fifty technical sessions. In honor of the release of the new C++11 standard, this May's conference will, for the first time, be offered in three tracks. In addition to the sessions that attendees have come to expecton topics like library design and usage, programming techniques, best practices, academic research, development tools, concurrency, reliability, and performancethis year's program includes a full track devoted to C++11 <http://cppnow.org/locations/c11/> and three keynotes by industry luminaries <http://cppnow.org/overview/> . For those eager to get on board with the new standard, the C++11 content features fifteen hours of tutorial material covering the most important new features and APIs, presented, in many cases, by the language designers themselves. C++ Now! is offering the most complete C++11 tutorial coverage of any conference this year! Conference speakers include book and library authors, academics, C++ Standard Committee members, tool builders, architects, and engineers. With our very high presenter-to-audience ratio, attendees will have ample opportunity for one-on-one interaction with leaders who are currently defining the state of the art in C++. Dave Abrahams, the conference co-chair, writes, "We planned for an expansion, but even I am surprised at the presenter response and the resulting depth of this year's program. I'm preparing for a flood of new attendees." Reserve your place today at http://cppnow.org/registration C++ Now! 2012, held May 13-18 in Aspen Colorado is hosted by Boost in cooperation with ACM. * Complete program: http://cppnow.org/schedule * Speakers: http://cppnow.org/participants * Registration: http://cppnow.org/registration Jon

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