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

Some questions about vertex removal in subgraph
by Nicholas Mario Wardhana 29 Mar '13

29 Mar '13

Hi all, In the last few days I have been implementing partial I/O for a subgraph by saving and loading a subgraph (although actually it is only partial if we see it from the parent graph's point of view). So far, by modifying some code in Boost, I managed to save a child graph to a file, and also load two subgraphs which share a vertex without having that vertex duplicated. However, in addition to save and load, I also need to clear (i.e. remove all nodes and edges from) a subgraph, and I found that remove_vertex is not implemented; only remove_edge is. I noticed that as of now (March 2013) there is no plan to implement it [1]. I cannot use Jeremiah's suggestion there (and also in [2]) to use filtered_graph, because I need to physically remove the nodes and edges from memory, so I am thinking to implement it myself. I have a few questions about this. 1) Jeremiah said that "In particular, local vertex descriptors in subgraphs are indices into an std::vector, and so removing a vertex would invalidate many other vertex descriptors." [1] Am I right to assume that this statement is about m_global_vertex, which is of std::vector<vertex_descriptor> type? 2) Removing a vertex from a regular graph involves calling g.m_vertices.erase(..) (adjacency_list.hpp, line 1951). I found that m_vertices is also of type std::vector. So why does vertex removal work for regular graph, but supposedly not for subgraph? I use Boost version 1.53.0, and my subgraph configuration is typedef adjacency_list<vecS, vecS, undirectedS, property<vertex_index_t, int, VertexProperty>, property<edge_index_t, int, EdgeProperty> > RegularGraph; typedef subgraph<RegularGraph> Subgraph; where VertexProperty and EdgeProperty are respectively bundled properties for vertex and edge. Thank you very much! Best regards, Nicholas Mario Wardhana References: [1] https://svn.boost.org/trac/boost/ticket/4752 [2] http://boost.2283326.n4.nabble.com/Can-t-link-subgraphs-because-remove-vert…

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Re: [Boost-users] header-only libraries
by dib 27 Mar '13

27 Mar '13

> > >> I'd like to use the program_options library, but am reluctant to > >> require my users to build parts of Boost. Is there a strong > >> reason that this library cannot be header-only? > > You can build the necessary Boost CPP files as part of your own > build. > Asio (which is header-only) offers the possibility for "optional separate compilation" by including some ".../impl/src.hpp" in a source file and defining either "BOOST_ASIO_SEPARATE_COMPILATION" or "BOOST_ASIO_DYN_LINK", which very nicely lets the user choose which one suits best for his needs. Is there a reason why this isn't done for other libs like program_options, regex, etc., or has it (at least sometimes) just not been done because nobody wanted to do this extra-work? It is a very frequently asked question if/why not there is a header-only version, and although it is sometimes really not possible to make it header-only, most libs should work that way. Furthermore, in my experience specially commercial projects are reluctant to use libraries that have to be shipped with the own product, whereas it is no problem as long as they are "hidden" inside the binary.. Of course there are some disadvantages as shown in the discussion on stackoverflow, but giving the user a choice where possible should hugely increase acceptance and usage of those libraries. Greetings, dib PS: I just tried it with program_options and at least with my programs on linux it works fine, don't know how it is on other platforms or if I was just lucky: copy the src-files from libs/program_options/src to the include/boost/program_options/impl and do it "the asio-way", including the source files in a separate .cpp in my projects.. works fine and no linking is required any more.

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header-only libraries
by ilya shlyakhter 26 Mar '13

26 Mar '13

Dear Boost experts, I'd like to use the program_options library, but am reluctant to require my users to build parts of Boost. Is there a strong reason that this library cannot be header-only? Or perhaps, it's possible to create a header-only version of this library? I have the same question for regex. Thanks, ilya

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[MSM] "favor_compile_time" policy disables "kleene" events. (Bug?)
by Deniz Bahadir 25 Mar '13

25 Mar '13

Hi everyone, Hi Christophe, While trying to speedup compilation of my MSM/eUML-based state machine, I seem to have found a bug. I added the "favor_compile_time" policy to the type-definition of my state-machine as the documentation suggests. I did not use the macro "BOOST_MSM_BACK_GENERATE_PROCESS_EVENT" because I do not have any sub-statemachines. This did speed up compilation, however obviously by changing my transition-table: All "kleene"-events in my transition-table are ignored, when defining the state-machine with the "favor_compile_time" policy. Can anyone confirm this or am I using it wrong? (Was this policy supposed to work with eUML in the first place?) Thanks, Deniz PS: I am using GCC 4.7.2 with Boost 1.53.

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Broken Links?
by Hei Chan 25 Mar '13

25 Mar '13

Hi, On http://www.boost.org/doc/libs/1_53_0/libs/pool/doc/html/boost_pool/pool/poo…, all the graphs there seem broken. Anyone fixing it? Thanks in advance. Cheers, Hei

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[boost::Statechart] posting a "serial timeout" event
by Andre de Jong 25 Mar '13

25 Mar '13

I've been using boost's asynchronous statechart to write a program. In this program I communicate with another device using an asynchronous serial port. I have a state that waits for a confirmation from the device over the serial port and then posts a "confirmation received" event. This works well but, I would also like to implement a "timeout" event. In previous programs I had been using switch case statements for my state machines where I had code that could be run each time the loop was run. This meant I could run code and check if I should change state due to something timing out. Like this: while(1){ switch (state){ case 0:{ sendMessage(); state = 1; sendTime = boost::chrono::steady_clock::now(); } break; case 1:{ if (isConfirmationReceived()){ // do something state = 2; } else if (boost::chrono::steady_clock::now() > start + boost::chrono::duration<double>(WAIT_LENGTH)){ //do something state = 3; } } break; // etc etc } } How would I implement something like this using boost::StateChart? Or, should i be thinking about this a completely different way?

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Re: [Boost-users] Broken Links?
by Boost_mailinglist＠gmx.de 25 Mar '13

25 Mar '13

Hello, you can see the directory listing of the pictures under http://www.boost.org/doc/libs/1_53_0/libs/pool/doc/images/ -----Ursprüngliche Nachricht----- Gesendet: Montag, 25 März 2013 um 06:32:27 Uhr Von: "Hei Chan" <structurechart(a)yahoo.com> An: "boost-users(a)lists.boost.org" <boost-users(a)lists.boost.org> Betreff: [Boost-users] Broken Links? Hi, On�http://www.boost.org/doc/libs/1_53_0/libs/pool/doc/html/boost_pool/pool/…, all the graphs there seem broken. Anyone fixing it? Thanks in advance. Cheers, Hei _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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bad reloc address when compiling with mingw
by Leonardo Sá 24 Mar '13

24 Mar '13

Hi all, I have been trying to create an .exe that links to several boost libraries (date-time, python, etc.) using MinGW, cross compiling for windows on linux. I compiled boost using mingw without problems. When linking the exe, I am receiving the following error: CMakeFiles/fp_core_test.dir/objects.a(MockEnvironment.cpp.obj):MockEnvironment.cpp:(.text+0x381): undefined reference to `fp_core::Window::init(int, int, boost::shared_ptr<fp_core::Renderer>)' /usr/bin/i686-w64-mingw32-ld: CMakeFiles/fp_core_test.dir/objects.a(MockEnvironment.cpp.obj): bad reloc address 0x8 in section `.text$_ZN5boost6detail15sp_counted_baseC2Ev[boost::detail::sp_counted_base::sp_counted_base()] I have no idea what "bad reloc address" means. Googling wasn't much help. Anyone can give me a pointer in the right direction? Thanks!

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newbie problem with Program Option string value
by Neil Sutton 24 Mar '13

24 Mar '13

I am having problems getting a program option to work. The option should enable a user to enter a location when they select the '--location' option. so, if you type --location canada, the code should store the supplied string - canada and pass it on to the program. This is a typical program option with nothing special. But I cannot seem to get it to work! Please look at this: ---------------------------------------------------- std::string place_option; // a global variable po::options_description general("General options"); general.add_options() ("location", po::value<std::string>(), "location of your home"); // there are other non string options po::variables_map vm; po::store(po::parse_command_line(ac,av, general),vm); po::notify(vm); if(vm.count("help")) { std::cout << general << "\n"; return 0; } if(vm.count("version, v")) { std::cout << "version aplha\n"; } if(vm.count("location")) { place_option = vm["location"].as<std::string>(); // should pass the string value entered at command line to std::string place. } If i run my program with eg 'myprogram --location disney' I get: terminate called after throwing an instance of 'std::logic_error' what(): basic_string::_S_construct NULL not valid Aborted ------------------------------ Now I have tried a few variations of the code. The examples show where an int value is supplied and retrieved. I cannot work out how to do - what should be very trivial. I simply want to recover the value associated with 'location' i.e a std::string entered at the command line. I then want to pass that value on to my program to do something with it. I do not understand the error. Can someone kindly show me the correct syntax to accomplish this please? Kind regards.

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[iostreams] mapped_file path issue
by Alexandre 24 Mar '13

24 Mar '13

Hello, After reading through all the documentation and examples I could read, I still can't get the following piece of code to work . I assume that when you pass a new_file_size and a path to the mapped_file_params class , it will then open the file at the location desired when I call the constructor of mapped_file with the mapped_file_params object in parameter. But the only thing it does is to create a file with a weird name , like "%F8/134" in the project working directory, not where I told it to. Maybe I'm wrong and one should create file before specifying it to the mapped_file? After reading the doc, I was under the assumption that it created a new file when you fill in the new_file_size param. and specifies the filename. Anyone experienced this before? Any advice on how to resolve this? Here's the code: boost::iostreams::mapped_file_params param(filename); // filename is a std::string with the correct path param.flags = boost::iostreams::mapped_file::mapmode::readwrite; param.new_file_size = sizeNeeded; // sizeNeeded is the size of the data param.length = sizeNeeded; boost::iostreams::mapped_file fileMap(param); // at this point the file is created … Thanks for your time, Alexandre

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[BGL] boost::disjoint_set getting new representative after link()
by Adi Shavit 23 Mar '13

23 Mar '13

Hi, I'm using boost::disjoint_sets_with_storage<>. After calling link(rep1, rep2), I want to know the new rep - the representative of the merged set. Obviously, I can call find_set(rep1) to find it. I assume that the extra call to find_set incurs an additional run-time cost per call to link. Is this true or is the call immediate (as in returning the immediate parent of rep1)? If it does incur a run-time cost, then we know that the new-rep is *either *rep1 or rep2. Is there some other way to know which one it is? On a related matter, I am also tracking the *size *of the sets for each link(). Does knowing the size of the rep set before the link help in determining which of rep1 or rep2 will be the new rep? Is there a simple way to extend boost::disjoint_sets_with_storage<> to do the size tracking internally (currenlty I keep an external size vector per rep to keep track of the link()s). Thanks, Adi

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erase and put methods in property tree lib of boost
by Sashidhar Guntury 23 Mar '13

23 Mar '13

I have been trying to use the put and erase methods in boost's property tree library with very limited success. I have tried to go through the documentation but it seems really esoteric with no real example to demonstrate. This is what I would like to do - I have a json object. I look for a particular key (call it "title") and extract the corresponding value (call it "Eric Clapton"), do something with "Eric Clapton" (say change it to "ec") insert it in the place of the old value. Now, should I do an "erase" to remove the previous entry and then "put" the new pair? Will "put" replace the old value? void doSomething(const ptree& node) { ... BOOST_FOREACH(const ptree::value_type& child, node.get_child("artists")) { string text = child.second.get<string>("title"); // do something to the text to give text2 child.second.put("title", text2); } ... } The above code gives an error which is equally hard to understand. I was hoping someone would shed some light. thanks Sashidhar

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[BGL] Error C2679 when inserting edge property to subgraph
by Nicholas Mario Wardhana 22 Mar '13

22 Mar '13

Hi all, Could somebody tell me how to add a bundled edge property for subgraph, please? The code, based on [1], is as follows. // code starts #include <boost/config.hpp> #include <boost/graph/subgraph.hpp> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/graph_utility.hpp> using namespace std; using namespace boost; struct VertexProperty { int intValue; }; struct EdgeProperty { std::size_t biconnected_component; int intValue; }; typedef adjacency_list<vecS, vecS, undirectedS, VertexProperty, property<edge_index_t, int, EdgeProperty> > PlainGraph; typedef subgraph<PlainGraph> Graph; int main(int argc, char* argv[]) { PlainGraph g1; Graph g(2); VertexProperty v0; v0.intValue = 1; VertexProperty v1; v0.intValue = 1; EdgeProperty e; e.biconnected_component = 0; e.intValue = 0; add_edge(0, 1, g); put(get(vertex_bundle,g), 0, v0); // OK put(get(vertex_bundle,g), 1, v1); // OK put(get(edge_bundle,g), 0, e); // error here return 0; } // code ends The error is as follows: // error starts 1>D:\API\boost_1_53_0\boost/property_map/property_map.hpp(361): error C2679: binary '[' : no operator found which takes a right-hand operand of type 'int' (or there is no acceptable conversion) 1> D:\API\boost_1_53_0\boost/graph/subgraph.hpp(797): could be 'EdgeProperty &boost::subgraph_global_property_map<GraphPtr,PropertyMap,Tag>::operator [](boost::detail::edge_desc_impl<Directed,Vertex>) const' 1> with 1> [ 1> GraphPtr=boost::subgraph<PlainGraph> , 1> PropertyMap=boost::adj_list_edge_property_map<boost::undirected_tag,EdgeProperty,EdgeProperty &,unsigned __int64,boost::property<boost::edge_index_t,int,EdgeProperty>,boost::edge_bundle_t>, 1> Tag=boost::edge_bundle_t, 1> Directed=boost::undirected_tag, 1> Vertex=unsigned __int64 1> ] 1> while trying to match the argument list '(const boost::subgraph_global_property_map<GraphPtr,PropertyMap,Tag>, int)' 1> with 1> [ 1> GraphPtr=boost::subgraph<PlainGraph> , 1> PropertyMap=boost::adj_list_edge_property_map<boost::undirected_tag,EdgeProperty,EdgeProperty &,unsigned __int64,boost::property<boost::edge_index_t,int,EdgeProperty>,boost::edge_bundle_t>, 1> Tag=boost::edge_bundle_t 1> ] 1> main.cpp(74) : see reference to function template instantiation 'void boost::put<boost::subgraph_global_property_map<GraphPtr,PropertyMap,Tag>,EdgeProperty&,int,EdgeProperty>(const boost::put_get_helper<Reference,LvaluePropertyMap> &,K,const V &)' being compiled 1> with 1> [ 1> GraphPtr=boost::subgraph<PlainGraph> , 1> PropertyMap=boost::adj_list_edge_property_map<boost::undirected_tag,EdgeProperty,EdgeProperty &,unsigned __int64,boost::property<boost::edge_index_t,int,EdgeProperty>,boost::edge_bundle_t>, 1> Tag=boost::edge_bundle_t, 1> Reference=EdgeProperty &, 1> LvaluePropertyMap=boost::subgraph_global_property_map<boost::subgraph<PlainGraph> ,boost::adj_list_edge_property_map<boost::undirected_tag,EdgeProperty,EdgeProperty &,unsigned __int64,boost::property<boost::edge_index_t,int,EdgeProperty>,boost::edge_bundle_t>,boost::edge_bundle_t>, 1> K=int, 1> V=EdgeProperty 1> ] 1> // error ends I found a few other threads [2, 3] about this, but their solutions don't solve the problem. BTW I use Visual Studio 2010 on Windows 7 64-bit. The Boost version is 1.53.0. Thank you! Best regards, Nicholas Mario Wardhana References: [1] http://boost.2283326.n4.nabble.com/BGL-Bundled-Properties-in-subgraphs-td25… [2] http://stackoverflow.com/questions/7608031/boost-subgraph-and-bundled-prope… [3] https://groups.google.com/forum/?fromgroups=#!topic/boost-list/5EIkKybaUTY

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[boost][units]: Looking for more elegant ways to define RPM and velocity[km/h]
by Dennis Gertitschke 22 Mar '13

22 Mar '13

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Martin Lester : 3/22/2013 4:03:04 AM
by Martin Lester 22 Mar '13

22 Mar '13

http://www.sanjose-personalinjuryattorney.com/btjh/bdmm.aabn Martin Lester 3/22/2013 4:03:04 AM

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[Thread] Constructing a move-only object asyncronously
by Alexander Lamaison 20 Mar '13

20 Mar '13

I'm trying to create a move-only object asyncronously using Boost.Thread unique_future but I'm running into trouble: error C2248: 'A::A' : cannot access private member declared in class 'A' c:\users\awl03\documents\visual studio 2005\projects\boost_1_51_0\boost\thread\future.hpp 493 I've tried all sorts of ways to work around this but always end up with some variation or other of this error message. What am I doing wrong? The code is below. The setup is: Visual Studio 2005 Boost 1.51 Thanks, Alex #include <boost/noncopyable.hpp> #include <boost/move/move.hpp> #include <boost/thread/future.hpp> #include <boost/thread/thread.hpp> using namespace boost; class A : public noncopyable { BOOST_MOVABLE_BUT_NOT_COPYABLE(A) public: A(int i) {} A(BOOST_RV_REF(A) other) {} A& operator=(BOOST_RV_REF(A) other) {} }; A create_a() { return A(42); } unique_future<A> async_create_a() { packaged_task<A> task(create_a); unique_future<A> result = task.get_future(); thread(move(task)).detach(); return move(result); } int main() { A a = async_create_a().get(); return 0; } -- Swish - Easy SFTP for Windows Explorer (http://www.swish-sftp.org)

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Re: [Boost-users] [graph] problem with weight_map ? (brandes_betweenness_centrality)
by The Maschine 20 Mar '13

20 Mar '13

Hi, ## > EdgeWeightProperty weight = getWeight(a, b); // 0f ... 2.0f Can you just assign a double to a boost::property<...> object? That should probably not be allowed. ## I found the example here and made my code: http://programmingexamples.net/wiki/CPP/Boost/BGL/DijkstraUndirected ### What happens if you write an explicit loop over all of the edges and use put(edge_weight, g, e) directly? Does that change any of the results? -- Jeremiah Willcock ### In not sure what you mean? Im not a super expert, can you please explain your thought more? Best, Tasos

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Boost Geometry Compilation Errors
by Joel Markham 20 Mar '13

20 Mar '13

Trying to use the boost geometry library. Have a very simple example from the boost geometry home page int main(int argc, const char * argv[]) { double points[][2] = {{2.0, 1.3}, {4.1, 3.0}, {5.3, 2.6}, {2.9, 0.7}, {2.0, 1.3}}; bgm::polygon<bgm::d2::point_xy<double> > poly; bg::append(poly, points); boost::tuple<double, double> p = boost::make_tuple(3.7, 2.0); std::cout << "Point p is in polygon? " << std::boolalpha << bg::within(p, poly) << std::endl; … } When trying to build on my Mac I get compiler warnings: point_type.hpp No matching function for call to 'assertion_failed" coordinate_type.hpp No matching function for call to 'assertion_failed" convert_point_to_point.hpp Call to function 'get that is neither visible in the template definition or found… access.hpp Nom member named 'get in boost::geometry::core_dispatch… Is there something wrong with the boost libraries installed via macports?

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[BGL] Dijkstra/A* with large graph
by Nicholas Mario Wardhana 20 Mar '13

20 Mar '13

Hi all, I am wondering if with Boost Graph Library, I can do either of these two things: 1) Merge several small graphs into one large graph 2) Save and load only a portion of a large graph at a time? So the background is as follows. I have a large geometric graph (i.e. a graph with 3D coordinate custom vertex properties), which I want to use for path planning. The graph can be too large to be stored in the memory (if I understand correctly, BGL uses STL data structures, which have limits for the number of elements), so I implement the large graph as multiple small graphs (let's just call them mini-graphs). This way, I can save the mini-graphs to hard-disk, and load only the necessary mini-graphs to plan the path (I have cost function to determine the mini-graphs using Dijkstra). The problem is, this breaks the connectivity of the original graph, and I also have to add some points to two mini-graphs. Running Dijkstra/A* is consequently not straightforward, since the starting and the goal nodes can be in different mini-graphs. The two aforementioned solutions can be used as a workaround. Using approach #1, I can combine the chosen mini-graphs into one, on which I can directly run Dijkstra/A*. In approach #2, I just have one variable of graph, while the mini-graphs can just be implemented as extra properties of the nodes and edges. This way, I can select which nodes and edges to load from the files (e.g. if a node has a mini-graph ID of 1, load the node). Having said that, I don't know how to implement those approaches with BGL. It seems to me that subgraph provides a hierarchically structured graph, but is it possible to just load a subgraph without loading the whole graph? BTW, I am wondering if BGL has an external memory variant, like Parallel BGL for multi-core environment? If not, is anybody aware if there is such library (preferrably free to use for research purpose)? Thank you! Best regards, Nicholas Mario Wardhana

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accessing last element in boost multi-index
by Mahmood Naderan 19 Mar '13

19 Mar '13

Hi Using boost::multiindex, I am looking for a method to retrieve the the last element. Something like rbegin(). As I looked in to the manual page, http://www.boost.org/doc/libs/1_53_0/libs/multi_index/doc/tutorial/basics.h…, I could not find such function. Problem with end() is that it points to the last_element+1 which is null. Regards, Mahmood

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[graph] problem with weight_map ? (brandes_betweenness_centrality)
by The Maschine 19 Mar '13

19 Mar '13

Hi all, I think I've got a problem with the way I use the weight property map in my betweenness_centrality (and maybe other locations too). I've got a graph like that: typedef boost::property<boost::edge_weight_t, double> EdgeWeightProperty; typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, VertexProperties, EdgeWeightProperty> unGraph; And I add edges with weights like that (simplified): EdgeWeightProperty weight = getWeight(a, b); // 0f ... 2.0f std::pair<unGraph::edge_descriptor, bool> e = boost::add_edge(a, b, weight, m_ugraph); Than I try to do the brandes_centrality_betweenness: std::vector< double > v_centrality_vec(boost::num_vertices(m_ugraph), 0.0); boost::brandes_betweenness_centrality(m_ugraph , boost::centrality_map(boost::make_iterator_property_map(v_centrality_vec.begin(),boost::get(boost::vertex_index, m_ugraph),double())).vertex_index_map(get(boost::vertex_index, m_ugraph)).weight_map(get(boost::edge_weight, m_ugraph)) ); But I get crazy results... 1) I have checked by hand that my "getWeight" (my weights) are OK. 2) I have set _ALL_ weights to 1.0 (almost as if brandes was using BFS internally), Again I get the _SAME_ crazy results! So there is something wrong with the way Im using the weight_map. What am I missing?? Best, Tasos

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[regex] using partial_match?
by Armel Asselin 19 Mar '13

19 Mar '13

[boost 1.53.0] Hello, I'd like to find in a stream of text either "abcd" or "ab". The text is not bounded in size, so I think I should use partial_match. However I present it the following text: "hello abc<cut_here>d, how are you?" it reports to find "ab" and does not wait for the second block to be appended. #include "boost/regex.hpp" int main(int argc, char* argv[]) { boost::regex re ("abcd|ab"); std::string str ("hello abc"); boost::match_results<std::string::const_iterator> results; bool found = boost::regex_search (str.cbegin(), str.cend(), results, re, boost::regex_constants::match_partial); if (!found || results[0].matched) printf("problem...\n"); return 0; } Am I doing something wrong? I see in the specification that "Specifies that if no match can be found, then ....", isn't this specification flowed? should not it be "if the regular expression engine needs to check past the end of the block of text, and the start matches partially, ...." ? I hope I am wrong and there are good flags to pass.... Regards Armel

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[range] contiguous iterators
by Stefan Strasser 19 Mar '13

19 Mar '13

Hi everyone, is there any way to generically determine at compiletime whether an iterator or a boost range refers to contiguous memory? i.e. &*(it+1) == (&*it)+1 some type trait like is_contiguous<T *>::value == true is_contiguous<vector<T>::iterator>::value == true is_contiguous<std::list<T>::iterator>::value == false ?

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Android: segfault while writing to archive during Serialization
by wespaugh 18 Mar '13

18 Mar '13

Greetings! New to discussion, apologies in advance for any inadvertent misuse of terminology / standards. (also, I tried e-mailing this post directly last night, but it doesn't appear to have shown up, yet. double-apologies if double-post). I'm trying to port my project, which involves some serialization code, to Android. I followed instructions to build boost 1.49 found here: https://github.com/MysticTreeGames/Boost-for-Android and can successfully compile my application using crystax NDK r7 (gcc 4.5.3) , and link it to the Serialization library. Unfortunately! When my application calls the serialization code to send my object to the archive, it crashes. I've reduced my actual code to try and isolate the crash in a way I can post here. std::ofstream outStream(MAP_SAVE_FILE, std::ios_base::binary); boost::archive::text_oarchive outputArchive(outStream, 1); Classroom *c = new Classroom(); CCLog("Outputting archive"); // outputArchive << mapInstance; outputArchive << c; The crash occurs at outputArchive << c; "Fatal signal 11 (SIGEGV) at 0xdeadbaad (code=1), thread 1870 (Thread-97)" which is a segfault, in Androidvania. Ideally I want to be outputting that mapInstance variable that's commented out to archive, but for sanity's sake I made a silly little Classroom class, which I'll include for sanity's sake: class Classroom { friend class boost::serialization::access; template <class Archive> void serialize( Archive &ar, const unsigned int version ) { ar & studentCount; } int studentCount; public: Classroom() { studentCount = 1; } ~Classroom(){} }; I've run across several red flags about wchar support in Android or on gcc versions, so I'm inclined to think that's related. Then again, it appears as though my boost configuration files were aware of the compiler version when it built (that Mystic Tree link at the top really does seem to be on top of things, if anyone's interested), which is how the program was able to compile and run, at all. I'm almost 100% certain this is related to the Android NDK, either the gcc version or the gnu-stl, because I can compile and run this code on Windows through Visual studio with no problem, but it crashes on Android. I've made sure that my app has write permissions to the internal storage being used. I can even write out text files using basic std::ostreams without a crash. I am not at all familiar with dealing with these sorts of compiler- or platform-specific issues; I have a bachelor's in SE which taught me design patterns, architecture, and project management, but nothing like this. I'd greatly appreciate some direction in learning how to work through these kinds of problems, (although I'd even more greatly appreciate an actual solution to the problem I'm seeing). Thanks in advance for any assistance. -- View this message in context: http://boost.2283326.n4.nabble.com/Android-segfault-while-writing-to-archiv… Sent from the Boost - Users mailing list archive at Nabble.com.

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boost serialization of std::pair
by Andrew Smith 18 Mar '13

18 Mar '13

Hi, Is there any way of customizing the element names given to serialization of std::pair via xml_oarchive. Im think of something like the|||BOOST_SERIALIZATION_NVP mechanism. In particular Im looking to serialize std::map with custom elemnet names to replace '<first>' and '<second>' Thanks Andy |

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