December 2011 - Boost-users - lists.preview.boost.org

[interprocess] Determine size of managed_shared_memory
by Kai Benndorf 12 Oct '19

12 Oct '19

Hi all, I want to create a managed_shared_memory in exactly the size I needed. Therefore I do something like this: size = sizeof( common_managed_shared_memory ); size += sizeof( MyClassInSharedMem ); managed_shared_memory segment(create_only, "name", size ); MyClassInSharedMem allocates itself some memory by segment->allocate(). I added this also to the size, but get a boost::interprocess::bad_alloc exception on allocating this additional memory. Are there some magic bytes I forgot to add? Many thanks in advance Kai

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[statechart] Passing parameters from event to State Local Storage
by Christophe Bourez 16 Nov '16

16 Nov '16

I need to maintain a parameter into the state local storage. This parameter is initially contained in the event that causes the transition to the target state. I give hereafter a small illustrative example. typename sc = boost::statechart; class EvTest : public sc::event<EvTest> { public: EvTest(std::size_t val) : value(val) {} std::size_t getValue() const { return this->value; } private: std::size_t value; }; class MyStateMachine; class StSource; class StTarget; class StSource : public sc::simple_state<StSource, MyStateMachine> { public: typedef sc::custom_reaction<EvTest> reactions; sc::result react(const EvTest &event) { // How to pass event.getValue() to the target state ? transit<StTarget>(); } }; class StTarget : public sc::simple_state<StTarget, MyStateMachine> { public: StTarget(std::size_t val) : val(value) {} private: std::size_t value; }; Thanks, Christophe

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Statechart serialization
by mbrodeur65 04 Mar '15

04 Mar '15

Hi, I'm looking for a solution to serialize boost::statechart objects. I'm aware that this feature is on the statechart library todo list but was wondering if there are any workaround to achieve this with the latest boost release (1.34) ? thanks for your help ! mbrodeur65 -- View this message in context: http://www.nabble.com/Statechart-serialization-tf4131326.html#a11749139 Sent from the Boost - Users mailing list archive at Nabble.com.

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[Thread] Read-write locks
by lfrfly＠icqmail.com 18 Sep '14

18 Sep '14

I'm trying to create a standard read/write lock using Boost Threads, and I'm having a bit of difficulty mapping the Boost concepts onto the usual ones. A read/write lock should have several states: Locked for reading (multiple threads may lock at once), locked for writing (only one thread may lock, and no threads may be locked for reading at the same time), and unlocked. Ideally it would be nice if an RWL which is locked for reading may temporarily upgrade to locked for writing, then return to the locked for reading state. Boost supports several relevant notions of locking: shared locking, upgrade locking, and exclusive locking. This to me is a confusing distinction. In particular, a shared_mutex seems appropriate as the basis for a RWL, but is lock_upgrade() the equivalent of a write lock and lock_shared the equivalent of a read lock? This is unclear. If "upgrade locking" is not the same as "exclusive locking", then is an upgrade lock actually exclusive? Could someone please clarify this.

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[Statechart] How to decide between post_event and process_event atrun time ?
by Philippe DAVID 22 Jul '14

22 Jul '14

Hi, I have a method in which I want to post/process an event. The thing is, this method can be called from outside the state machine (so I need to call process_event), or indirectly by a reaction of the state machine (in this case I must call post_event since process_event is not reentrant). I don't want to write 2 distinct methods to do this (one that calls post, and the other process), I would much rather prefer adding a 'if' in my method that tells me if I have to call process_event or post_event (if I'm being called indirectly by the state machine or not). Is there a way to do this with statechart ? regards, Philippe

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[asio] resolver::cancel() problem
by Matthew Edwards 14 Mar '14

14 Mar '14

In my application (and a separate test program) it seems as though the cancel() function on the resolver does not work as intended. For async resolves, the cancel functionality should abort them immediately and pass an 'operation aborted' error code to the callback handler. In my tests, I will resolve an invalid domain (this causes the resolve to take a few seconds, to demonstrate the problem), sleep for 100ms, then call cancel on the resolver object. No cancelling actually occurs, and the callback is simply triggered after a few seconds with a "No host found" error code, not the expected operation aborted. Has anyone experienced this before, or know how I might be using the resolver incorrectly?

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[BGL] Having a cost function as weight map
by Maxime van Noppen 06 Sep '13

06 Sep '13

Hi, I can't find how to do this pretty basic thing : having a function instead of a field to compute the cost of edges for various path finding algorithms. I couldn't find the answer in the documentation and Google was of no help. Did I miss something obvious ? Example : ------------------- #include <boost/graph/dijkstra_shortest_paths.hpp> #include <boost/graph/graph_traits.hpp> #include <boost/graph/adjacency_list.hpp> struct my_edge { double cost() const { return cost_ * 2; } double cost_; }; struct my_node { }; int main() { typedef boost::adjacency_list< boost::vecS, boost::vecS, boost::directedS, my_node, my_edge > graph_t; typedef boost::graph_traits<graph_t>::vertex_descriptor vertex_t; graph_t graph; vertex_t v /*= ... */; using boost::weight_map; // Works : boost::dijkstra_shortest_paths(graph, v, weight_map(boost::get(&my_edge::cost_, graph))); // Doesn't compile : //boost::dijkstra_shortest_paths(graph, v, // weight_map(boost::get(&my_edge::cost, graph))); } ------------------- Thanks ! -- Maxime

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can't get first example in boost tutorial to work
by 7stud 11 Mar '13

11 Mar '13

I'm trying to install boost on mac osx 10.4.7. I followed the tutorial "Getting Started on Unix Variants" found here: http://www.boost.org/doc/libs/1_35_0/ more/getting_started/unix-variants.html Following the instructions in the tutorial, I installed boost in /usr/local as instructed, so my directory structure is: /usr/local/boost_1_34_1/boost But when I run the first example in the tutorial: #include <boost/lambda/lambda.hpp> #include <iostream> #include <iterator> #include <algorithm> int main() { using namespace boost::lambda; typedef std::istream_iterator<int> in; std::for_each(in(std::cin), in(), std::cout << (_1 * 3) << " " ); } I get the error(among others): error: boost/lambda/lambda.hpp: No such file or directory If I change the include path to: #include </user/local/boost_1_34_1/boost/lambda/lambda.hpp> I get the error(among others): error: boost/lambda/core.hpp: No such file or directory But core.hpp is in the lambda directory: /usr/local/boost_1_34_1/boost/lambda$ ls algorithm.hpp control_structures.hpp lambda.hpp bind.hpp core.hpp loops.hpp casts.hpp detail numeric.hpp closures.hpp exceptions.hpp switch.hpp construct.hpp if.hpp I'm using the Xcode 2.4 IDE to run my C++ programs. I also tried to execute the program from the command line with the original include path: #include <boost/lambda/lambda.hpp> but I get the same error: ~/2testing/dir1$ g++ prog1.cpp prog1.cpp:1:35: error: boost/lambda/lambda.hpp: No such file or directory prog1.cpp: In function 'int main()': prog1.cpp:8: error: 'boost' has not been declared prog1.cpp:8: error: expected namespace-name before ';' token prog1.cpp:8: error: '<type error>' is not a namespace prog1.cpp:11: error: '_1' was not declared in this scope I get the same errors again with the full include path: #include </user/local/boost_1_34_1/boost/lambda/lambda.hpp> $ g++ prog1.cpp In file included from prog1.cpp:1: /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:14:33: error: boost/lambda/core.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:21:52: error: boost/lambda/detail/operator_actions.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:22:61: error: boost/lambda/detail/operator_lambda_func_base.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:23:63: error: boost/lambda/detail/operator_return_type_traits.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:26:45: error: boost/lambda/detail/operators.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:30:46: error: boost/lambda/detail/member_ptr.hpp: No such file or directory prog1.cpp: In function 'int main()': prog1.cpp:8: error: 'boost' has not been declared prog1.cpp:8: error: expected namespace-name before ';' token prog1.cpp:8: error: '<type error>' is not a namespace prog1.cpp:11: error: '_1' was not declared in this scope What path should I be using? Or, should I set an environment variable somewhere?

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[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

2 1

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.

1 1

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 15 Jan '12

15 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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[BGL] getting an edge_descriptor of a reverse_graph
by Alex Hagen-Zanker 06 Jan '12

06 Jan '12

I upgraded from boost 1.45 to 1.48 and there are some breaking changes related to reverse_graph The main problem that I encounter is that boost::edge(u ,v, graph) returns a edge_descriptor to the graph that underlies reverse_graph, rather than reverse_graph itself . The following therefore does not compile: template<typename Graph> void foo(Graph& graph) { boost::graph_traits<Graph>::edge_descriptor e = boost::edge(0, 1, graph).first; } int main() { boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS> graph(2); foo(graph); // this line compiles foo(boost::make_reverse_graph(graph)); // this line does not compile } Do you have suggestions how to rewrite foo(Graph& graph) in order to generically work for both plain and reversed graphs? For now I have rewritten the boost::edge function in reverse_graph.hpp to return a pair<reverse_graph_edge_descriptor, bool> but that does not seem right. Thanks, Alex

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Boost::shared::memory consistency
by Josmon Paul 06 Jan '12

06 Jan '12

4 8

[BGL] Finding the descriptor for a given vertex
by Kelvin Chung 05 Jan '12

05 Jan '12

Suppose I have the following: template <class T> class Graph { // Adapter class that I use for my purposes typedef typename boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, T> innerGraph; typedef typename boost::graph_traits<innerGraph>::vertex_descriptor VertexDescriptor; innerGraph G; public: void addVertex(const T& vertex); bool containsVertex(const T& vertex) const; void addEdge(const T& from, const T& to); // More stuff here }; The intent of this adapter class is to basically abstract out all the mentions of stuff like the descriptors and such. So a good helper function to this end would be a function that retrieves the VertexDescriptor for a given T, if it exists. Is there such a function already in the BGL, or do I have to manage that separately (ie. having an external map)?

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[Phoenix][v3] Argument/State dependent return type of actors?
by Josef Weinbub 05 Jan '12

05 Jan '12

Hi Recently I made myself familiar with Phoenix v3, more specifically with actors. I did a few test implementations, and I wondered if there is a way to access the argument types (nested in the context's environment) and/or the type of the state(s) (nested in the proto expression) for the actor's result type declaration. Have a look at the following actor dummy implementation, especially at the line ''typedef int result_type;'': (for the sake of completeness, the complete actor implementation is provided) ------------------------------------------------------------ BOOST_PHOENIX_DEFINE_EXPRESSION( (boost)(phoenix)(myactor) , (boost::phoenix::meta_grammar) ) struct myactor_eval { // ------------------------ // the result type can not be made dependable from // one of the actors argument types .. it is // typedef int result_type; // ------------------------ template <typename StateExpr, typename Context> result_type operator()(StateExpr const& state_expr, Context & ctx) const { return -1; } }; namespace boost { namespace phoenix { template <> struct default_actions::when< rule::myactor> : boost::phoenix::call< ::myactor_eval> {}; template <typename T> typename expression::myactor<T>::type const inline myactor(T& t) { return expression::myactor<T>::make(t); } }} ------------------------------------------------------------ As I already stated, I wonder if there is a way to have access to the argument and state types for the result type, maybe as it was possible in Phoenix v2 via a nested template struct which got the same template parameters as the functor, like the simple example in the following: ------------------------------------------------------------ struct myactor_eval { template <typename StateExpr, typename Context> struct result { typedef typename result_of::env<Context>::type Environment; typedef typename remove_reference< Environment>::type::args_type Args; typedef typename result_of::value_at_c< Args, 0>::type Parameter; // make the result type argument dependent! typedef typename Parameter::value_type type; }; ... }; ------------------------------------------------------------ I do hope that I haven't overlooked something in the docs, sorry if I did. Thanks for your support! Cheers, Josef Weinbub

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[Container] deque emplace() requirements
by Szymon Gatner 04 Jan '12

04 Jan '12

Hi, question: why container::deque<T>::emplace_back() requires T to be copyable? Shouldn't it just be using placement new operator with passed c-tor params? Unless growing of deque causes elements to be copied which is not what I want at all (hence deque and not vector). Cheers, Simon -- Szymon Gatner The Lordz Games Studio www.thelordzgamesstudio.com

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[phoenix] ambiguity between std::begin/end and phoenix::begin/end due to ADL
by Nathan Ridge 04 Jan '12

04 Jan '12

Hello, I am running into a problem where an unqualified call to begin() on a range type whose template parameters include a Boost.Phoenix type (for examle filtered_range<Pred, R> where Pred is a phoenix function) is ambiguous because, in addition to the intended std::begin, phoenix::begin is being found by ADL. What can be done about this? There exists precedent for placing boost::xxx::begin/end functions in ADL barrier namespaces because C++11 encourages unqualified calls to begin/end (specifically, this was done for boost::range::begin/end). Should the same thing be done for Phoenix? Here is a minimal example that reproduces the problem: #include <iterator> #include <boost/range/adaptor/filtered.hpp> #include <boost/phoenix/phoenix.hpp> using std::begin; int main() { using boost::phoenix::arg_names::arg1; using boost::adaptors::filtered; int v[5]; const auto& f = v | filtered(arg1 < 0); begin(f); } And here are the errors, with GCC 4.7: test.cpp: In function 'int main()': test.cpp:15:12: error: call of overloaded 'begin( const boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less , boost::proto::argsns_::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal , boost::proto::argsns_::term< boost::phoenix::argument<1> >, 0l > >, boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal , boost::proto::argsns_::term<int>, 0l > > >, 2l > >, int [5] > & )' is ambiguous test.cpp:15:12: candidates are: In file included from string:53:0, from c++/4.7.0/bits/locale_classes.h:42, from ios_base.h:43, [STL Decryptor: Suppressed 3 more STL standard header messages] from test.cpp:1: c++/4.7.0/bits/range_access.h:58:5: decltype ( __cont.begin() ) begin( const boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost::proto::argsns_ ::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term< boost::phoenix::argument<1> >, 0l> >, boost ::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term<int>, 0l> > >, 2l> >, int [5]>; decltype (__cont.begin()) = boost::filter_iterator< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost::proto::argsns_ ::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term< boost::phoenix::argument<1> >, 0l> >, boost ::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term<int>, 0l> > >, 2l> >, int *> &) c++/4.7.0/bits/range_access.h:48:5: decltype ( __cont.begin() ) begin( const boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost::proto::argsns_ ::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term< boost::phoenix::argument<1> >, 0l> >, boost ::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term<int>, 0l> > >, 2l> >, int [5]>; decltype (__cont.begin()) = boost::filter_iterator< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost::proto::argsns_ ::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term< boost::phoenix::argument<1> >, 0l> >, boost ::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term<int>, 0l> > >, 2l> >, int *> &) In file included from boost/boost/phoenix/stl/container.hpp:11:0, from boost/boost/phoenix/stl.hpp:16, from boost/boost/phoenix/phoenix.hpp:18, from test.cpp:4: boost/boost/phoenix/stl/container/container.hpp:794:1: const boost ::phoenix::detail::expression::function_eval< boost::phoenix::stl::begin, boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost::proto::argsns_ ::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term< boost::phoenix::argument<1> >, 0l> >, boost ::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term<int>, 0l> > >, 2l> >, int [5]>; boost::phoenix::detail::expression::function_eval< boost::phoenix::stl::begin, A0>::type = boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::phoenix::detail::tag::function_eval, boost::proto ::argsns_::list2< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost::proto ::argsns_::term<boost::phoenix::stl::begin>, 0l>, boost ::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost::proto ::argsns_::term< boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost ::proto::argsns_::list2< boost::phoenix::actor< boost::proto::exprns_ ::basic_expr< boost::proto::tagns_::tag ::terminal, boost::proto ::argsns_::term< boost::phoenix ::argument<1> >, 0l> >, boost::phoenix::actor< boost::proto::exprns_ ::basic_expr< boost::proto::tagns_::tag ::terminal, boost::proto ::argsns_::term<int>, 0l> > >, 2l> >, int [5]> >, 0l> >, 2l> > >::type boost::phoenix::begin( const boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost::proto::argsns_ ::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term< boost::phoenix::argument<1> >, 0l> >, boost ::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term<int>, 0l> > >, 2l> >, int [5]>; boost::phoenix::detail::expression::function_eval< boost::phoenix::stl::begin, A0>::type = boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::phoenix::detail::tag::function_eval, boost::proto ::argsns_::list2< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost::proto ::argsns_::term<boost::phoenix::stl::begin>, 0l>, boost ::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost::proto ::argsns_::term< boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost ::proto::argsns_::list2< boost::phoenix::actor< boost::proto::exprns_ ::basic_expr< boost::proto::tagns_::tag ::terminal, boost::proto ::argsns_::term< boost::phoenix ::argument<1> >, 0l> >, boost::phoenix::actor< boost::proto::exprns_ ::basic_expr< boost::proto::tagns_::tag ::terminal, boost::proto ::argsns_::term<int>, 0l> > >, 2l> >, int [5]> >, 0l> >, 2l> > &) Thanks, Nate

3 2

property type trait
by Amir Yazdanbakhsh 02 Jan '12

02 Jan '12

Hi, I new to boost graph library. The thing that I have in my mind is to find the type of property that passed to a function and execute something based on that. I implemented two bundled properties each for vertex and edge. I want to implement a general function, say print a property, if the passed property is a vertex property the function should iterate over vertices and print out them and if it's edge property it should iterate over edges. Is it any way to do that? Thanks Best Regards, A. Yazdanbakhsh >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> PhD. Student School of Electrical and Computer Engineering University of Wisconsin-Madison E-mail: yazdanbakhsh(a)wisc.edu <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

2 1

[multi_array]bug in strides calculation with some storage orderings
by Larry Evans 02 Jan '12

02 Jan '12

If I understand correctly, the multi_array storage order determines which strides are larger than others. In short: if( order[I]>order[I+1]) then stride[I]>stride[I+1] However, the output from the attached code shows that this is not always true. In the attached code, the mono_tonic_print function tests the conditions and prints out the results. The following partial output: :count=3 :permut_v={ 1, 2, 0} :permut_i={ 2, 0, 1} :ma.ordering(*)==permut_v=1 :multi_array_strides:strides()={ 12, 1, 3} :monotonically increasing={ 0, 0} :is_mono_tonic=0 :expected_strides:{ 4, 8, 1} :monotonically increasing={ 1, 1} :is_mono_tonic=1 :count=4 :permut_v={ 2, 0, 1} :permut_i={ 1, 2, 0} :ma.ordering(*)==permut_v=1 :multi_array_strides:strides()={ 4, 8, 1} :monotonically increasing={ 0, 0} :is_mono_tonic=0 :expected_strides:{ 12, 1, 3} :monotonically increasing={ 1, 1} :is_mono_tonic=1 shows that the multi_array code fails this monotonic constrait when the order is one of: :permut_v={ 1, 2, 0} :permut_v={ 2, 0, 1} The code also shows a possible solution. This possible solution uses the inverse permutation instead of the original permutation to calculate the strides, as shown in the expected_strides function. There's also a macro, NO_INVERT_PERMUT, which, if defined, has expected_strides reproduce the multi_array strides, which may help narrow down the source of the error in multi_array's stride calculation. The output is also attached. If macro INDENT_OUTPUT is defined, the code requires: http://svn.boost.org/svn/boost/sandbox/variadic_templates/boost/iostreams/f… http://svn.boost.org/svn/boost/sandbox/variadic_templates/boost/iostreams/u… http://svn.boost.org/svn/boost/sandbox/variadic_templates/boost/utility/tra… http://svn.boost.org/svn/boost/sandbox/variadic_templates/boost/utility/ind… If you don't want to download those, then the output will not be nicely indented as shown in the attached output. HTH. -regards, Larry

1 1

iterate over vertices with special propoerty
by Amir Yazdanbakhsh 01 Jan '12

01 Jan '12

Hi, I want to write an iterator which returns the vertices with a special property. For example have an functions which takes a graph and a string and returns an iterator over all the vertices that have this string as their name. Thanks Best Regards, A. Yazdanbakhsh >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> PhD. Student School of Electrical and Computer Engineering University of Wisconsin-Madison E-mail: yazdanbakhsh(a)wisc.edu <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

2 1

[inteprocess] timed_lock absolute time
by Edward Diener 01 Jan '12

01 Jan '12

Is the "absolute time" mentioned when using a mutex and timed_lock a local time or a UTC time ? I am guessing a local time but I just want to make sure.

2 5

Re: [Boost-users] Problem with Interpocess offset_ptr
by mike＠tesla.rcub.bg.ac.rs 30 Dec '11

30 Dec '11

Thank you Ion, it solved my problem. Qtree now works good and fast!

1 0

Build error on Solaris 10
by İhsan Doğan 30 Dec '11

30 Dec '11

Hi, I'm new to Boost and while trying to build it on Solaris 10 using the sun Toolset and the and Sun Studio 12.1 compiler I'm running into this issue: sun.archive bin.v2/libs/exception/build/sun/release/link-static/stdlib-sun-stlport/threading-multi/libboost_exception.a "CC" -xar -o "bin.v2/libs/exception/build/sun/release/link-static/stdlib-sun-stlport/threading-multi/libboost_exception.a" "bin.v2/libs/exception/build/sun/release/link-static/stdlib-sun-stlport/threading-multi/clone_current_exception_non_intrusive.o" common.copy stage/lib/libboost_exception.a cp "bin.v2/libs/exception/build/sun/release/link-static/stdlib-sun-stlport/threading-multi/libboost_exception.a" "stage/lib/libboost_exception.a" ...failed updating 4 targets... I'm kinda stuck here. What could be the reason for this error? Ihsan -- ihsan(a)dogan.ch http://blog.dogan.ch/

1 0

tcp error “more data is available”
by herzl&revital sham 29 Dec '11

29 Dec '11

I build a sync udp server via boost::asio follow bellow I bind to interface Socket.open(EndPoint.protocol()); Socket.set_option(boost::asio::ip::udp::socket::reuse_address(true)); Socket.bind(EndPoint); and read char mybuffer[1450]; Socket.async_receive_from( boost::asio::buffer(mybuffer, 1450), senderEndpoint_, boost::bind(&MsgReceiver::HandleReceive, this, boost::asio::placeholders::error, buffer, boost::asio::placeholders::bytes_transferred) ); then i send data to this server like below: yes "AAAAAAAAAAAAAAAAAaaAAAAAAA" | nc -u 172.16.0.12 1234 I get "more data is available" error message in HandleReceive and my system Crashes. I debugger this is all io_services status 0 > 5768 Worker Thread _threadstartex boost::asio::detail::win_iocp_io_service::work_finished Normal 0

1 0

boost::interprocess::string
by Josmon Paul 29 Dec '11

29 Dec '11

2 1

Problem with Interpocess offset_ptr
by mike＠tesla.rcub.bg.ac.rs 29 Dec '11

29 Dec '11

Hi, I need to store in the shared memory structure for Quadtree. It is a class with 4 pointers for tree regions and vector of points: class CNode4 { ... CNode4* node0; CNode4* node1; CNode4* node2; CNode4* node3; vector<vec2> pointArray; }; I have tried with class CNode4 { ... offset_ptr<CSNode4> node0; ... }; and using as: typedef allocator<void, managed_shared_memory::segment_manager> void_allocator; const void_allocator alloc_void(segment.get_segment_manager()); CSNode4* rootNode = segment.construct<CSNode4> (_RootNode) (alloc_void); rootNode->node0 = new CSNode4(alloc_void,...); this works until I try to static_cast node0 offset_ptr<CSNode4> N1 = static_cast<CSNode4*>(rootNode->node0); I get: (MSVC 2010, boost 1.42) error C2440: 'static_cast' : cannot convert from 'boost::interprocess::offset_ptr<PointedType>' to 'CSNode4 *' what am I doing wrong? Thanks, Ivan

2 1

Build boost with Apple's LLVM 3.0
by Daniel Dilts 29 Dec '11

29 Dec '11

I am building boost on OS X 10.7.2. Using ./bootstrap.sh ./b2 sudo ./b2 install it appears to build with the GCC 4.2.1 toolchain. How would I change this so that it builds using the LLVM 3.0 toolchain?

2 2

Using the /RTC option without specifying a debug runtime will lead to linker errors
by Sleat, Ben 28 Dec '11

28 Dec '11

Hi I'm trying to track down a very nasty stack corruption bug in my release code and therefore I would like to enabled the Visual C++ RTCs option to enable runtime stack checks in my release build, however when I try to do this I get an "Incompatible build options" error from the boost libraries. Specifically I get this from boosts AutoLink.hpp: #if defined(__MSVC_RUNTIME_CHECKS) && !defined(_DEBUG) # pragma message("Using the /RTC option without specifying a debug runtime will lead to linker errors") # pragma message("Hint: go to the code generation options and switch to one of the debugging runtimes") # error "Incompatible build options" #endif It seems to be suggesting that in order to use /RTC I need to do a Debug build, buts that's exactly what I don't want to do... I need to enable Runtime Checks in the Release build! Is there any way to get this to work in a release build that uses boost? Does anyone know the details of the incompatibility? Surely /RTC doesn't require all linked in DLLs also to be compiled with /RTC? Thanks in advance. Ben This email is from Verint Systems UK Ltd and is confidential. If you have received it in error, please advise us and then delete the original and any attachments it may have contained. Verint Systems UK Ltd does not accept any responsibility for viruses. Verint Systems UK Ltd is a limited company registered in England and Wales at 241 Brooklands Road, Weybridge, Surrey KT13 0RH ,registration number 2602824. VAT registration number GB566153238.

3 5

boost::asio::buffer + std::wstring
by Luke Walker 28 Dec '11

28 Dec '11

Hi, I'm sending unicode text over a socket using boost::asio::async_write and boost::asio::buffer however only 1/4 of the string ends up at the receiver. What must I do so that all bytes are sent? Thanks!

2 6

[Python] Wrapping Visitor Pattern and Object Slicing
by Alex Olivas 27 Dec '11

27 Dec '11

Hey All, I'm trying to wrap a third party lib that uses the visitor pattern and their own smart pointers ('ref_ptr' below), which manages objects that inherit from 'Referenced'. I've put together a simple example that illustrates the problem. Code for python bindings : http://codepad.org/wq47m5CI Simple test script : http://codepad.org/Jfme3U6U Output for two cases : http://codepad.org/gbFBxy04 Case 1) 'apply' override is commented out in the python class Case 2) 'apply' override exists The problem that I'm having is that the 'apply' method ( lines 83 - 86 ) slices everything to base unless I use boost::ref(). However this only works for wrapped classes and in this lib several classes use derived visitors that are not part of the public API ( which I modeled as HelperVisitor in the above example ). Is there anyway to prevent object slicing for both wrapped and unwrapped objects in this scenario? I'm building against boost 1.47 and if anyone's interested in digging deeper the 3rd party lib is Open Scene Graph 3.0.1. Thanks, Alex.

1 0

Re: [Boost-users] filesystem::path threadsafe ?? (1.48) Options
by Aris Basic 27 Dec '11

27 Dec '11

Here is the sample code that crashes every time i compile project as multibyte and not unicode and ahve user wchar_t as default type #include <boost/thread.hpp> #include <boost/filesystem.hpp> int main(void) { std::string sPath("c:\\Development"); boost::thread_group tg; for(int i = 0; i < 10; i++) { tg.create_thread([&sPath](){ boost::this_thread::sleep(boost::posix_time::milliseconds(10)); boost::filesystem::path p(sPath); boost::filesystem::directory_iterator di(p), end; while(di != end) std::cout << (*di).path().string() << std::endl; }); } tg.join_all(); }

3 3

Boost.Container string operator+ problem
by dave_chp 27 Dec '11

27 Dec '11

Using boost 1.48 and vs2010 gives me an error when trying to use boost::container::string. #include <boost/container/string.hpp> int main( int, char *[] ) { using boost::container::string; string hello = "hello "; string world = "world"; string hello_world = hello + world; } 1>d:\sdk\boost_1_48_0\boost\container\string.hpp(2368): error C2248: 'boost::container::containers_detail::basic_string_base ::alloc' : cannot access protected member declared in class 'boost::container::containers_detail::basic_string_base ' 1> with 1> [ 1> A=std::allocator<char> 1> ] 1> d:\sdk\boost_1_48_0\boost\container\string.hpp(214) : see declaration of 'boost::container::containers_detail::basic_string_base ::alloc' 1> with 1> [ 1> A=std::allocator<char> 1> ] 1> d:\tmp\xxx.cpp(15) : see reference to function template instantiation 'boost::container::basic_string<CharT,Traits,A> boost::container::operator +<char,std::char_traits<char>,std::allocator<_Ty>>(const boost::container::basic_string<CharT,Traits,A> &,const boost::container::basic_string<CharT,Traits,A> &)' being compiled 1> with 1> [ 1> CharT=char, 1> Traits=std::char_traits<char>, 1> A=std::allocator<char>, 1> _Ty=char 1> ] 1> d:\tmp\xxx.cpp(20) : see reference to function template instantiation 'void hello_world_test<boost::container::string>(void)' being compiled 1> template <class CharT, class Traits, class A> inline basic_string<CharT,Traits,A> operator+(const basic_string<CharT,Traits,A>& x, const basic_string<CharT,Traits,A>& y) { ... str_t result(reserve, x.size() + y.size(), x.alloc()); ... } should this maybe be x.get_allocator() instead of x.alloc()? -- View this message in context: http://boost.2283326.n4.nabble.com/Boost-Container-string-operator-problem-… Sent from the Boost - Users mailing list archive at Nabble.com.

2 2

[smart_ptr] Inclusion of unique_ptr
by Szymon Gatner 27 Dec '11

27 Dec '11

Hi, as suggested by Dave Abrahams I am now turning here with proposition of including unique_ptr<> to smart_ptr library. Newly accepted boost.move enables portable implementation and move-aware containers in boost.container allow to take full advantage of this now standard pointer type. Attaching proposed implementation. -- Szymon Gatner The Lordz Games Studio www.thelordzgamesstudio.com

3 2

whitebox testing with boost unit test framework?
by Chris Cleeland 26 Dec '11

26 Dec '11

I'm using the boost unit test framework to implement unit tests for code. I'm wondering if there is a best-practice for doing white-box testing/internal state inspection of types under test. My hack right now is to strip out "protected" and "private" from the header, but I hold my nose as I do that. Thoughts/suggestions? -- Chris Cleeland

7 16

A* heuristic
by giridhar 24 Dec '11

24 Dec '11

Hello All, I have a question about defining A* heuristic. I am trying to implement an algorithm in a paper using BGL. Here authors have used A* Dijkstra's to calculate shortest route with an additional constraint of route length should be no longer than a threshold value t. I think due to this threshold constraint they are using A* instead of normal Dijkstra's algorithm. I came to know A* is already there in Boost Graph Library. I just have a basic knowledge about A* algorithm that it finds the shortest route based on the heuristic H. I tried to look into the example in BGL, but I did not get any hint to define a heuristic. Can anybody give me some hints or some useful links of how can I define a heuristic for this particular scenario of finding the shortest path between nodes that is no longer than threshold t through A* Dijkstra. This would be really helpful for me to proceed further. -- Regards, Giridhar

5 5

Problem with boost ::interprocess::string
by Josmon Paul 23 Dec '11

23 Dec '11

3 2

filesystem::path threadsafe ?? (1.48)
by Aris Basic 22 Dec '11

22 Dec '11

is filesystem::path threadsafe ? i think im seeing issues related to conversion of std::string to std::wstring (that is being used by path on windows) (so thats put blame onto string to wstring conversion) did anyone see anything like that ? if not ill try to create a small sample app that recreates the issue. code portion <similar code run in multiple threads> std::string spath("c:\\somefolder"); fs::path path(spath); // i get crash within this call seems like conversion is using static instance of codecvt and it breaks on call in (do_in) maybe its just windows codecvt issue

1 0

Using boost::uuids::uuid as a map index
by Tim Burgess 22 Dec '11

22 Dec '11

Hi, I'm new to using boost and have hit a problem using UUID. I have a set of classes that have UUID variables to provide unique identifiers. I wish to achieve two things: 1 - Allow objects to reference each other based on their UUID values (imagine the usual databasing student/teacher/course models); 2 - Maintain std::map collections of objects of the same class. Initially, I made the mistake of creating a class instance containing my UUID then inserting it into a map: Std::map <boost::uuid::uid, myClass> myMap; The index of the entry was set as follows: Std::pair <boost::uuids::uuid, myClass> myPair; myPair = std::make_pair( myClassInstance.UUIDField, myClassInstance); myMap.insert( myPair); All look-ups within the map based on the UUID then fail, as adding the object to the map is essentially a copy operation and UUID is non-copyable, so new unique identifiers were generated. I then tried: Std::map <boost::uuids::uuid *, myClass*> myMap; I thought that this should work as the actual UUID value would only ever be held in a single instance of myClass and the relationships between objects could be maintained by following the pointers. Unfortunately, look-ups using this scheme also fail and I can't see where I'm going wrong. Can anybody advise, please? Best wishes. Tim Burgess Raised Bar Ltd Phone: +44 (0)1827 719822 Don't forget to vote for improved access to music and music technology at http://www.raisedbar.net/petition.htm -----Original Message----- From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Cromwell Enage Sent: 10 December 2011 05:42 To: boost-users(a)lists.boost.org Subject: [Boost-users] [boost-users][container] associative placement insertion Hi, all! I'm wondering how placement insertion works for pair-associative Boost.Container types. For example, given: //[ex_code struct D { D(char,char) {} // Insert Boost.Move awareness here... }; boost::container::map<int,D> my_map; //] Will my_map.emplace(0, 't', 'p') call D('t', 'p') and move the object into the map? Will Boost.Unordered work the same way? TIA! Cromwell D. Enage _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

3 4

boost::polygon::polygon_set
by Egon Schaal 22 Dec '11

22 Dec '11

Hello I have a question to use the function template <typename T, typename coord_type> T& simplify(T& polygon_set, distance_type threshold) How must I define the parameter distance_type My typedefs are set to typedef boost::polygon::point_data<double> point; typedef boost::polygon::polygon_set_data<double> polygon_set; typedef boost::polygon::polygon_with_holes_data<double> polygonwh; typedef boost::polygon::polygon_data<double> polygon; I think the distance_type must be a double. Mit freundlichen Grüßen / Best regards Egon Schaal ///////////////////////////////////////////////// Egon Schaal CAD-Consulting, Softwareerstellung Aspacherstr. 15 71522 Backnang Email egon.schaal(a)cad-cons.net Web http://www.cad-cons.com Tel (+49)7191-84498 Fax (+49)7191-71410 SteuerNr: 51336/01006 /////////////////////////////////////////////////

1 0

Please help me to choose a container
by Jayden Shui 21 Dec '11

21 Dec '11

Hi All, I have a number of named objects of type B whose name can be accessed by B::Name(). B is polymorphic. D1, D2 and so on are derived from B. I want to put them in a set or map-like container ordered by their names. They are referenced by other objects, such as of type C. If the objects in the container are changed by its type (from type D1 to D2) or value, their users can know it automatically, i.e. those information is shared among owners and users. To erase an object in the container, first we need to ensure it is not be used by other objects. Please help me on choose a proper container with smart pointers. I am struggling with it by trying multi-index-container, pointer container, standard container, and cannot find a good way. Thanks a lot ! ! Best regards, Jayden

4 5

How to make multi_index_container work with std::unique_ptr?
by Jayden Shui 21 Dec '11

21 Dec '11

Hi All, If the elements of a multi_index_container are std::unique_ptr, it doesn't seem to work because the assignment operator of std::unique_ptr is private. Any way to let it work? If I change unique_ptr to shared_ptr, it works. But I need a good performance. Or is there anyway to work around to get pointer container performance with multi index power? Thanks a lot! Jayden

3 10