April 2010 - Boost-users - lists.preview.boost.org

[Graph] Problem trying to delete vertices from a graph using named vertices, please help!
by Camillo Anania 02 Apr '10

02 Apr '10

Hi guys, I have a graph so defined: typedef boost::adjacency_list<boost::listS, boost::listS, boost::bidirectionalS, Osm::VertexProperties, EdgeProperties> Graph; Graph osmGraph; I'm trying to delete some vertices from osmGraph using the usual remove_vertex(Vertex, Graph) but I get the following error from Visual Studio 2008 when compiling: boost_1_40_0\boost/graph/named_graph.hpp(349) : error C2664: 'boost::multi_index::detail::hashed_index_iterator<Node,BucketArray> boost::multi_index::detail::hashed_index<KeyFromValue,Hash,Pred,SuperMeta,TagList,Category>::erase(boost::multi_index::detail::hashed_index_iterator<Node,BucketArray>)' : cannot convert parameter 1 from 'void *' to 'boost::multi_index::detail::hashed_index_iterator<Node,BucketArray>' the code I use is: { vector<int> component(num_vertices(osmGraph)); int num = strong_components(osmGraph, make_iterator_property_map(&component[0], get(&Osm::VertexProperties::id, osmGraph)), vertex_index_map(get(&Osm::VertexProperties::id, osmGraph))); int main_comp = component[depotID]; for (int i = 0; i != component.size(); i++){ if (component[i] == main_comp) continue; if (is_incident_to_required_edge(osmGraph, i)){ cerr << "Required components on input topology are not strongly connected. Check the input .osm file" << endl; return 1; } else { clear_vertex(osm_get_vertex(i, osmGraph), osmGraph); Osm::Vertex osm_v = osm_get_vertex(i, osmGraph); cout << "id=" << osmGraph[osm_v].id << endl; remove_vertex(osm_v, osmGraph); } } } why it doesnt work? why the same code with the graph defined in the following way works? typedef adjacency_list < listS, listS, bidirectionalS, property < vertex_name_t, std::string, //vertex property property < vertex_unique_id_t, int, property < vertex_color_t, boost::default_color_type> ............. >, //edge property property < edge_index_t, int, property < edge_num_bins_t, int, property < edge_unique_id_t, int, property < edge_name_t, std::string> ..............> > Graph; PLEASE help. Camillo Ciao

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Release 1.12 of the C++ Middleware Writer on line
by Brian Wood 01 Apr '10

01 Apr '10

B"H Release 1.12 of the C++ Middleware Writer is now on line. This release fixes several bugs and adds support for the following: 1. Multiple inheritance, but we don't support virtual inheritance yet. G-d willing, we'll add that later. 2. boost::scoped_ptr, auto_ptr/unique_ptr. 3. Accounts An account is now needed to use the command line interface of the C++ Middleware Writer. When an account is created, a directory will be associated with the account. That directory is reused with each request and only the input files that have changed since your last request are transmitted. The command line interface config file, direct.cfg, refers to an Account-Number. That file has to be updated after you set up an account. Use this page -- http://webEbenezer.net/cgi-bin/account.cgi -- to set up an account. Setting up an account is currently trivial -- no questions asked -- just click the button. There's an example of the multiple inheritance and scoped_ptr support here -- http://webEbenezer.net/release/112.example . Cheers, Brian Wood http://www.webEbenezer.net (651) 251-9384

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trying to build custom property_map
by Sandeep Gupta 01 Apr '10

01 Apr '10

Hi, I created a simple property_map as follows: struct VecMap { typedef int value_type; typedef int key_type; typedef read_write_property_map_tag category; typedef int* reference; std::vector<int> vec_store; }; void put(VecMap& rmap, int key, int val) { rmap.vec_store[key] = val; } int get(VecMap& rmap, int key) { return rmap.vec_store[key]; } /// End code The compiler gcc-4.4.1 against latest boost-trunk gives errorerror: no type named value_type in struct boost::property_traits<VecMap> The code however compiles fine with boost_1_40. Please take a look. The full code is available here http://codepad.org/KtmbXkLa Thanks Sandeep

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[Boost-build] Bjam flags
by Carlos 01 Apr '10

01 Apr '10

Hi, I need to use the "whole-archive" flag to force an executable to link some static objects. I know how to do it with autotools, but it is possible to do using boost-build system? Thanks

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Cross compiling boost 1.33.1
by srinath duraisamy 01 Apr '10

01 Apr '10

Hi all, I have to cross compile the boost 1.33.1 for my development board. I downloaded boost_1_33_1 from the sourceforge download page and I followed the steps provided as per this link ( http://www.boost.org/doc/tools/build/doc/html/bbv2/tasks/crosscompile.html ) 1. specify your cross compiler in user-config.jam using gcc : arm : arm-none-linux-gnueabi-g++ ; 2. bjam toolset=gcc-arm It needs bjam, so I download and installed the bjam from boost download page. when I run bjam toolset=gcc-arm, I am getting the following error: don't know how to make toolset=gcc-arm ...found 1 target... ...can't find 1 target... It will be very helpful, if someone guide me with the steps to cross compile boost1.33.1 version. Thanks in advance.

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Help for using interprocess::managed_mapped_file
by Kanthimathi Kalyanamandapam 01 Apr '10

01 Apr '10

Hi: I am experimenting with managed_mapped_file to store a vector of a complex_data encapsulating a string and an array quite like the provided "containers of containers" example. However, the program behaves in a rather erratic manner , throwing up boost::interprocess_exception::library_error quite randomly after inserting a few elements. I am including the program below , any help on this will be highly appreciated, With Regards, Kanthi K ///////////////////////// // Compile with: g++ -ansi -Wall -O2 -lrt -o output progname.cc #include <iostream> #include <string> #include <map> #include <list> #include <boost/tuple/tuple.hpp> #include <boost/interprocess/managed_mapped_file.hpp> #include <boost/interprocess/allocators/allocator.hpp> #include <boost/interprocess/containers/string.hpp> #include <boost/interprocess/containers/vector.hpp> #include <boost/interprocess/exceptions.hpp> #define MEGABYTE 1048576L /** * Class for storing data in a mmap file */ class memmapfile { private: typedef boost::interprocess::managed_mapped_file managed_mapped_file_t; typedef managed_mapped_file_t::segment_manager segment_manager_t; typedef boost::interprocess::allocator<void, segment_manager_t> void_alloc; typedef boost::interprocess::allocator<int, segment_manager_t> int_alloc; typedef boost::interprocess::allocator<char, segment_manager_t> char_alloc; typedef boost::interprocess::vector<int, int_alloc> mm_int_vector; typedef boost::interprocess::basic_string<char, std::char_traits<char>, char_alloc> mm_string; typedef std::list<int> std_int_list; /* holder */ struct holder { holder(mm_string mstr, mm_int_vector mintvec) : mstr_(boost::interprocess::move(mstr)), mintvec_(boost::interprocess::move(mintvec)) { } ~holder() {} private: mm_string mstr_; mm_int_vector mintvec_; }; typedef boost::interprocess::allocator<holder, segment_manager_t> holder_alloc; typedef boost::interprocess::vector<holder, holder_alloc> mm_holder_vector; /** functions */ /** segment functions */ void open_file() { segment = managed_mapped_file_t(boost::interprocess::open_or_create, file_location_.c_str(), file_size_); void_alloc alloc_inst(segment.get_segment_manager()); mm_holder_vector *usevec; usevec = segment.find_or_construct<mm_holder_vector> (boost::interprocess::unique_instance) (alloc_inst); std::cerr << "Vec Size at open : " << usevec->size() << std::endl; } void grow_file(std::size_t ExtraBytes) { if (ExtraBytes <= 0) ExtraBytes=file_incr_unit; std::cerr << "Growing file : " << file_size_ << " + " << ExtraBytes << " = "; segment.grow(file_location_.c_str(),ExtraBytes); segment = managed_mapped_file_t(boost::interprocess::open_only, file_location_.c_str()); file_size_ = segment.get_size(); std::cerr << file_size_ << std::endl; } void init_usevec(bool clear) { void_alloc alloc_inst(segment.get_segment_manager()); mm_holder_vector *usevec; std::size_t count=0; boost::tie(usevec,count) = segment.find<mm_holder_vector> (boost::interprocess::unique_instance); if (count==0) { std::cerr << "Cannot find vector" << std::endl; exit(1); } if (clear) { std::cerr << "Clearing vector" << std::endl; segment.destroy<mm_holder_vector>(boost::interprocess::unique_instance); usevec = segment.construct<mm_holder_vector> (boost::interprocess::unique_instance) (alloc_inst); } } /* variables */ std::string file_location_; std::size_t file_size_; const std::size_t file_incr_unit; managed_mapped_file_t segment; public: memmapfile(const std::string file_location, const std::size_t file_size, bool clear) : file_location_(file_location), file_size_(file_size), file_incr_unit(file_size) { try { open_file(); if (file_size_ > segment.get_size()) grow_file(file_size_ - segment.get_size()); init_usevec(clear); } catch (...) { std::cerr << " Cannot init mmapfile " << std::endl; exit(1); } } virtual ~memmapfile() {} /** * add: add an entry */ template<class T> std::size_t add(const std::string& in_str, const T& in_list) { std::size_t ret=0; try { std::size_t min_space_need = (in_str.length() * sizeof(char)) + (in_list.size() * sizeof(typename T::value_type)); while ( min_space_need*4 > segment.get_free_memory() ) { grow_file(file_incr_unit); } void_alloc alloc_inst(segment.get_segment_manager()); mm_holder_vector *usevec; std::size_t count=0; boost::tie(usevec,count) = segment.find<mm_holder_vector> (boost::interprocess::unique_instance); if (count==0) { std::cerr << "Cannot find vector" << std::endl; exit(1); } mm_string move_mstr(alloc_inst); mm_int_vector move_mintvec(alloc_inst); move_mstr = in_str.c_str(); for (typename T::const_iterator it = in_list.begin() ; it!= in_list.end() ; ++it) { move_mintvec.push_back(*it); } usevec->push_back(holder(move_mstr,move_mintvec)); ret = usevec->size(); std::cerr << "Added, Vec size: " << usevec->size() << "/" << usevec->max_size() << ", "; std::cerr << "Memory free: " << segment.get_free_memory() << "/" << segment.get_size() << ", "; double f = ((double)segment.get_free_memory()/(double)segment.get_size()) * 100; std::cerr << "% : " << f << std::endl; } catch (boost::interprocess::interprocess_exception e) { std::cerr << "Cannot add: " << e.what() << std::endl; exit(1); } return ret; } }; int main() { typedef std::list<int> std_int_list; std::string in_str = "abcdefghijklmnopqrstuvwxyz"; std_int_list in_list; for (int i=0; i<1024*8; ++i) { in_list.push_back(i) ; } std::size_t min_space_need = (in_str.length() * sizeof(char)) + (in_list.size() * sizeof(std_int_list::value_type)); std::cerr << "#### min space needed: " << min_space_need << std::endl; memmapfile* m = new memmapfile("test.bin",MEGABYTE,false); int i=0; while (++i<100) { std::size_t sz = m->add<std_int_list>(in_str,in_list); std::cerr << "Added in main loop: " << sz << std::endl; } } Your Mail works best with the New Yahoo Optimized IE8. 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inappropriate ADL
by Volker Schöch 01 Apr '10

01 Apr '10

Hi all, given this code... #include <deque> #include <boost/algorithm/string/find.hpp> #include <boost/operators.hpp> template< class Rng, class T > typename boost::range_iterator<Rng>::type find( Rng& rng, T const& t ) { return std::find( boost::begin(rng), boost::end(rng), t ); } struct STest : boost::equality_comparable<STest> { bool operator==(STest const& test) const { return true; } }; void main() { std::deque<STest> deq; find( deq, STest() ); } ...the VS9 compiler fails with "error C2668: 'find' : ambiguous call to overloaded function". This is due to the fact that STest inherits from a type that is defined in boost namespace which triggers the compiler to try ADL which finds boost::algorithm::find(RangeT& Input, const FinderT& Finder). An obvious solution is to prefix the call to find(...) with ::, but this feels wrong: It does not make sense that the compiler does ADL in this case. There is nothing special about boost::equality_comparable<...> that would make it a more natural argument for boost::algorithm::find(RangeT& Input, const FinderT& Finder) than any other type, and there is nothing special about boost::algorithm::find(RangeT& Input, const FinderT& Finder) that would make it a more natural find implementation for boost::equality_comparable<...> than my find(Rng& rng, T const& t). Maybe the function and the type should not be in the same namespace in the first place. Currently, the mere presence of the specific implementation boost::algorithm::find(RangeT& Input, const FinderT& Finder) disallows the implementation of the canonical find(Rng& rng, T const& t). Opinions? Suggestions? Thanks a lot, Volker -- Volker Schöch · vschoech(a)think-cell.com Senior Software Engineer think-cell Software GmbH · Chausseestr. 8/E · 10115 Berlin, Germany http://www.think-cell.com · phone +49 30 666473-10 · toll-free (US) +1 800 891 8091 Directors: Dr. Markus Hannebauer, Dr. Arno Schoedl · Amtsgericht Berlin-Charlottenburg, HRB 85229

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[serialization] baffled by very long archive load time
by Martin Weinberg 01 Apr '10

01 Apr '10

I have been developing and maintaining a large computatation statistics package (http://www.astro.umass.edu/BIE) It is an MPI application that uses boost::sersialization to implement persistence. After recently adding a new class, I notice that the archive load times have gone from seconds to over an hour!! The binary archive size is 30MB. Regression tests suggest that the resumed state is correct albeit the very long load time. The package is implemented in multiple shared libraries and classes are exported as suggested in the documentation. I have noticed that I need to compile with "-Ox -fno-inline-small-functions" when x=2,3. I'm not sure if this is significant. The system is Debian/GNU Linux, 2.2Ghz 0pteron 64bit. The behavior is the same with Boost 1.37, 1.38 and 1.42. The new class has many nested STL container instances e.g. vector< vector<float> > . . . but very few archived pointers. I've not been able to isolate the cause in test cases (e.g. making very large instances of STL nested containers; these are deserialized in under a second). Any thoughts on things to track down? Thanks! -- Martin Weinberg Phone: (413) 545-3821 Dept. of Astronomy FAX: (413) 545-4223 530 Graduate Research Tower weinberg(a)astro.umass.edu University of Massachusetts Amherst, MA 01003-4525

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[Iostreams] How to check whether file has ben opened?
by Daniel Eiband 01 Apr '10

01 Apr '10

Hi, I'm using Boost 1.42.0 and I have the same problem like vandamme described in this post at the end: http://groups.google.com/group/boost-list/browse_thread/thread/c290c987bf1f… The following code will assert if the file "test" does not exist: std::string filename("test"); boost::iostreams::stream<boost::iostreams::file_source> file; file.open(filename.c_str()); if (file.is_open()) { // assert fires if file "test" does not exist assert(boost::filesystem::exists(filename)); } The indirect_streambuf doesn't check the device and just returns true if open has been called (independent of whether open has been successful). If I use the std::ifstream supplied with MSVC 9.0 is_open() returns false if the file does not exits. Checked by replacing file declaration with: std::ifstream file; Is this a bug? If not how can I test whether opening the stream succeeds? Thanks, Daniel

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boost::thread destructor and detach()
by Eric J. Holtman 01 Apr '10

01 Apr '10

It looks like the new C++ standard threading library is going to call terminate() on a thread if it's being destructed, and has not been detached or joined. Is boost::thread going to change to emulate that behavior? (Currently, it calls detach(), not terminate()). I hadn't been calling detach () in my programs when I was spinning off a thread that I didn't care about joining later. Should I be doing that, just so my code works with either library?

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