December 2011 - Boost-users

[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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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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Recommended mock framework to use with Boost?
by doug livesey 15 Mar '12

15 Mar '12

Hi -- I'm trying to learn to develop properly with C++ and Boost, and to that end am learning along with Boost.Test, as I'm a BDD coder in another language (Ruby) in my day job. I'm at the point, now, where my tests could really benefit from a mocking framework. There doesn't appear to be one in Boost (not documented, at least), so I wondered if anyone on the list could recommend a mocking framework that they use that works well with Boost.Test? Any and all advice gratefully received, Doug.

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Boost.Generic sources?
by Nathan Ridge 05 Mar '12

05 Mar '12

I just read about the Boost.Generic library at https://github.com/boostcon/2011_presentations/raw/master/thu/Boost.Generic…. It looks amazing! I understand it's not fully complete, but are the sources available somewhere? Thanks, Nate.

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[multi_array] How to specify degenerate at runtime?
by Anton Daneyko 29 Feb '12

29 Feb '12

Greetings to Boosters, I have a 3D multi_array and I would like to make 2D slices using dimensions specified at runtime. I know the index of degenerate dimension and an index of slice, that I want to extract in that degenerate dimension. Currently the ugly workaround looks like that: if (0 == degenerate_dimension) { Slice slice = input_array[boost::indices[slice_index][range()][range()]]; } else if (1 == degenerate_dimension) { Slice slice = input_array[boost::indices[range()][slice_index][range()]]; } else if (2 == degenerate_dimension) { Slice slice = input_array[boost::indices[range()][range()][slice_index]]; } Is there a more beautiful way to construct index_gen object? Something like that: var slicer; for(int i = 0; i < 3; ++i) { if (degenerate_dimension == i) slicer = boost::indices[slice_index]; else slicer = boost::indices[range()]; } Slice slice = input_array[slicer]; It seems each subsequent call to boost::indices::operator[] returns a different type depending on the dimensionality, so there's no way to use a single variable, that can hold the temporary index_gen object.

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BGL defining my own iterator?
by Anders Wallin 24 Jan '12

24 Jan '12

Hi all, For traversing the faces of a planar BGL graph I store 'next' pointers in a bundled property for each edge. I can go round a face of the graph like this: BGLGraph g; edge_descriptor current,start; // initialize these! do { // do something with current current=g[current].next; } while(current!=start); Now I was thinking that a lot of 'boilerplate' code would be eliminated if I could do these loops with BOOST_FOREACH. Following the tutorial for iterator_facade I am trying something like this: https://github.com/aewallin/sandbox/blob/master/bgl_iterator/main.cpp However as commented in the code it doesn't quite work. I get either no iterations, one iteration, or all but one edge. Also, holding a pointer to an edge_descriptor in the iterator class doesn't strike me as very elegant, could I store an edge_descriptor directly? suggestions? thanks, AW

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Boost interprocess vector, creating multiple vector pointers
by Prasanth Madhavan 14 Jan '12

14 Jan '12

I want to insert a shared vector into a shared map using the following code: managed_shared_memory segment(create_only ,"MySharedMemory" ,65536); typedef allocator<int, managed_shared_memory::segment_manager> vecAllocator;typedef vector<int, vecAllocator> vec;typedef std::pair<int, vec* > ValueType;typedef allocator<ValueType, managed_shared_memory::segment_manager> ShmemAllocator;typedef multimap<int, vec*, std::less<int>, ShmemAllocator> MyMap; ShmemAllocator alloc_inst (segment.get_segment_manager());vecAllocator vectorallocator (segment.get_segment_manager()); MyMap *mymap = segment.construct<MyMap>("MyMap")(std::less<int>(),alloc_inst);vec *myvec = segment.construct<vec>("myvec")(vectorallocator);vec *myvec1 = segment.construct<vec>("myvec1")(vectorallocator); myvec->push_back(10);myvec->push_back(9);myvec->push_back(8);myvec1->push_back(987);myvec1->push_back(123);myvec1->push_back(456); for(int i = 0; i < 6; ++i){ for(int j = 0; j<6; j++) mymap->insert(std::pair<int, vec*>(i, myvec));}for(int i = 0; i < 6; ++i){ for(int j = 0; j<6; j++) mymap->insert(std::pair<int, vec*>(i, myvec1));}the code works.. but what i want to do is construct a vector without a name. that is do something like this vec *myvec = segment.construct<vec>(vectorallocator);vec *myvec1 = segment.construct<vec>(vectorallocator);so that if i put it inside a loop and there is no problem with naming them differently every loop. Is there a way to do so? Or atleast is there an automatic way to name them differently every loop? -- Prasanth Madhavan

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