September 2009 - Boost-users

[Regex] Group of number at line end
by Reiner Hutsch 23 Sep '09

23 Sep '09

Hallo regex gurus, i am looking for a regular expression which extracts a group of number from the end of a line like the following: "This line may contain digits (9) but ends with numbers like 1 2 3 4 5" When using a regex like "^(.+)(\\s+(\\d+))+$" I receive "This line may contain digits (9) but ends with numbers like 1 2 3 4" and "5". Can someone help me? RHutsch

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wget
by Matthew Galati 23 Sep '09

23 Sep '09

Is there a way to get boost libraries with wget via some ftp server? I am on linux and want to write a script to grab the source directly.

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BGL - read_graphviz and subgraph
by Giuseppe Di Guglielmo 22 Sep '09

22 Sep '09

Dear all, I read on the 'read_graphviz()' page in BGL library doc http://www.boost.org/doc/libs/1_40_0/libs/graph/doc/read_graphviz.html * read_graphviz treats subgraphs as syntactic sugar. It does not reflect subgraphs as actual entities in the BGL. Rather, they are used to shorten some edge definitions as well as to give a subset of all nodes or edges certain properties. For example, the DOT graphs digraph { a -> subgraph {b -> c} -> e } and digraph { a -> b -> e ; a -> c -> e ; b -> c} are equivalent. Is this actually true? Can I read sub-graph from DOT description and obtain a subgraph object? http://www.boost.org/doc/libs/1_40_0/libs/graph/doc/subgraph.html Eventually are subgraph supported by 'read_graphml()' function? http://www.boost.org/doc/libs/1_40_0/libs/graph/doc/read_graphml.html Thanks, G.

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Fwd: Sockets & acceptors
by Wes Alvaro 22 Sep '09

22 Sep '09

I've looked at the examples and tutorials and have destroyed my code trying to get this to work: * I want to connect to a server on a shared port and get a new port number and a unique ID. * The server should accept connections on a shared port and then open a new port to continue communication. * This happens synchronously. Currently, I can connect to the server: tcp::resolver resolver(io); tcp::resolver::query query(server, port); tcp::resolver::iterator endpoint_iterator = resolver.resolve(query); tcp::resolver::iterator end; boost::system::error_code error = boost::asio::error::host_not_found; while (error && endpoint_iterator != end) { serverSocket.close(); serverSocket.connect(*endpoint_iterator++, error); } if (error) { throw boost::system::system_error(error); } int messageSize = sizeof(ident) * 2 + sizeof(int); // ID and port void *message = malloc(messageSize); boost::asio::read(serverSocket, boost::asio::buffer((char *) message, messageSize)); The server code, ripped from the example: tcp::endpoint endpoint( tcp::v4(), this->listenPort ); tcp::acceptor a( io, endpoint ); do { boost::shared_ptr<tcp::socket> sock(new tcp::socket( io )); this->listenSocket = sock; a.accept( *this->listenSocket ); } while(true); As you can see, the server does nothing with the client connection. However, the client reads the 12 bytes as requested in the last line with boost::asio::read. The information received here is junk (to my program) and causes it to crash. What am I doing wrong? What should I be doing? Any help is much appreciated! Thanks, Wes

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Re: [Boost-users] boost zlib problem on linux (works fine onwindows)
by ChristinaDRS 22 Sep '09

22 Sep '09

Hey Steven, Can you post example code to do this? I'm very new to boost! Thanks, Christina >>Try calling flush on the streambuf. >>In Christ, >>Steven Watanabe ChristinaDRS wrote: > This code works fine on Windows, but I get the exception when running in > linux.. any ideas why? The code, how its compiled, and error are below: > > #include <iostream> > #include <sstream> > #include <boost/iostreams/copy.hpp> > #include <boost/iostreams/device/back_inserter.hpp> > #include <boost/iostreams/filter/bzip2.hpp> > #include <boost/iostreams/filter/zlib.hpp> > #include <boost/iostreams/filtering_stream.hpp> > using namespace std; > > int main() > { > string message = "this is a test message!"; > cout << "message: " << message << endl; > string compressed; > boost::iostreams::filtering_streambuf<boost::iostreams::output> > out; > out.push(boost::iostreams::zlib_compressor()); > out.push(boost::iostreams::back_inserter(compressed)); > boost::iostreams::copy(boost::make_iterator_range(message), out); > cout << "compressed message: " << compressed << endl; > > boost::iostreams::filtering_streambuf<boost::iostreams::input> in; > in.push(boost::iostreams::zlib_decompressor()); > in.push(boost::make_iterator_range(compressed)); > string decompressed; > boost::iostreams::copy(in, > boost::iostreams::back_inserter(decompressed)); > cout << "decompressed message: " << decompressed << endl; > } > > > # g++ zlib.cpp zlib_test2.cpp -o zlib_test2 -lz > # ./zlib_test2 > message: this is a test message! > compressed message: > terminate called after throwing an instance of > 'boost::iostreams::zlib_error' > what(): zlib error > Aborted > # > Try calling flush on the streambuf. In Christ, Steven Watanabe _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users -- View this message in context: http://www.nabble.com/Re%3A--Boost-users--boost-zlib-problem-on-linux-%28wo… Sent from the Boost - Users mailing list archive at Nabble.com.

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boost zlib problem on linux (works fine on windows)
by ChristinaDRS 22 Sep '09

22 Sep '09

Hello all, This code works fine on Windows, but I get the exception when running in linux.. any ideas why? The code, how its compiled, and error are below: #include <iostream> #include <sstream> #include <boost/iostreams/copy.hpp> #include <boost/iostreams/device/back_inserter.hpp> #include <boost/iostreams/filter/bzip2.hpp> #include <boost/iostreams/filter/zlib.hpp> #include <boost/iostreams/filtering_stream.hpp> using namespace std; int main() { string message = "this is a test message!"; cout << "message: " << message << endl; string compressed; boost::iostreams::filtering_streambuf<boost::iostreams::output> out; out.push(boost::iostreams::zlib_compressor()); out.push(boost::iostreams::back_inserter(compressed)); boost::iostreams::copy(boost::make_iterator_range(message), out); cout << "compressed message: " << compressed << endl; boost::iostreams::filtering_streambuf<boost::iostreams::input> in; in.push(boost::iostreams::zlib_decompressor()); in.push(boost::make_iterator_range(compressed)); string decompressed; boost::iostreams::copy(in, boost::iostreams::back_inserter(decompressed)); cout << "decompressed message: " << decompressed << endl; } # g++ zlib.cpp zlib_test2.cpp -o zlib_test2 -lz # ./zlib_test2 message: this is a test message! compressed message: terminate called after throwing an instance of 'boost::iostreams::zlib_error' what(): zlib error Aborted # Thanks! Christina -- View this message in context: http://www.nabble.com/boost-zlib-problem-on-linux-%28works-fine-on-windows%… Sent from the Boost - Users mailing list archive at Nabble.com.

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Using boost::serialization in real-time without allocating memory
by Peter Soetens 22 Sep '09

22 Sep '09

Hi, I'm trying to find out if boost::serialization can be used in real-time applications to stream data into a fifo to another process. It is mandatory that no memory allocations happen during the serialization. I tested this with a std::vector<double> of 10 elements in combination with the boost::iostreams library. The aim is that all memory allocations happen during construction of the archive object, while the serialisation itself causes none. <code> #include <boost/archive/binary_oarchive.hpp> #include <boost/serialization/vector.hpp> #include <boost/iostreams/stream.hpp> #include <boost/iostreams/device/array.hpp> namespace io = boost::iostreams; int main(int argc, char *argv[]) { vector<double> d(10, 1.1); char sink[1000]; memset( sink, 0, 1000); io::stream<io::array_sink> out(sink,1000); boost::archive::binary_oarchive oa(out); //oa << d; // should not allocate return 0; } </code> The setup code does 10 memory allocations according to valgrind: ==12995== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 8 from 1) ==12995== malloc/free: in use at exit: 0 bytes in 0 blocks. ==12995== malloc/free: 10 allocs, 10 frees, 913 bytes allocated. ==12995== For counts of detected errors, rerun with: -v ==12995== All heap blocks were freed -- no leaks are possible. If we uncomment 'oa << d' we get 2 more (unwanted) allocations: ==13010== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 8 from 1) ==13010== malloc/free: in use at exit: 0 bytes in 0 blocks. ==13010== malloc/free: 12 allocs, 12 frees, 1,001 bytes allocated. ==13010== For counts of detected errors, rerun with: -v ==13010== All heap blocks were freed -- no leaks are possible I'm guessing that the 2 allocations in the serialisation path come from a temporay std::string object, when writing the 'serialization::archive' string into the archive. Wouldn't it be possible to rewrite this library code as such that there are no allocations / strings created ? A similar pattern is observed for deserializing: 2 allocs in the serialisation path. Peter PS: I tried to find out who defines the macro BOOST_ARCHIVE_SIGNATURE() but I couldn't find the definition/#define !?

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typelist using mpl::list
by noman javed 22 Sep '09

22 Sep '09

Hi I want to implement typelist concept through mpl::list or mpl::vector. The idea is that for every call to some functor i want to store its type in a mpl::list e.g suppose we have struct A { }; A callA() {}; struct B {}; B callB() {}; main() { callA(); callB(); } this program should create a compile time mpl::list containing {B,A}. How can I implement this concept using mpl::list or mpl::vector ? Thanks in advance Regards Noman

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[program_options] vector parameters not working.
by aiooua 22 Sep '09

22 Sep '09

hello, I recently picked up boost to make use of the various libraries it includes. Unfortunately, I got stuck with the very first one (program_options) I used in my code. Any help would be appreciated very much. I want an option "bunch" which goes along with a bunch of numbers. I thought the following code would do the job: --------------------------------------------------------------------------------------- #include <iostream> #include <string> #include <vector> #include <boost/program_options.hpp> using namespace std; namespace po = boost::program_options; int main(int argc, char* argv[]) { try { vector<int> numbers; po::options_description params("parameters"); po::variables_map options; params.add_options() ("bunch,b", po::value< vector<int> >(&numbers), "a bunch of numbers"); po::store(po::parse_command_line(argc, argv, params), options); po::notify(options); if(options.count("bunch")!=0) { copy (numbers.begin(), numbers.end(), std::ostream_iterator<int>(cout, "\n")); } } catch(exception & e) { cerr << e.what() << endl; } return 0; }; --------------------------------------------------------------------------------------- However, it doesn't seem to work as it should. When I run this as follows: --------------------------------------------------------------------------------------- > test --bunch 4 2 42 4 --------------------------------------------------------------------------------------- It is just printing the first value - Am I doing something wrong here? I'm using 'boost_1_40_0' which I compiled using MS Visual Studio 2005. thanks,

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Status inquiry on Boost.Move
by Phil Deets 22 Sep '09

22 Sep '09

Hello, I am looking for a way to support move semantics with a few of my classes in a personal project I am working on. As soon as Visual C++ 2010 Express Edition comes out, I plan to convert the code to use R-value references, but I would prefer to have move semantics now so I can avoid needless expensive copies now. The Boost.Move code in the sandbox (http://svn.boost.org/svn/boost/sandbox/move/) seems to meet my needs, but I have not tried it yet; so I do not know whether it is stable or not. Does anyone know the status of this implementation. Is it relatively bug-free or should I not use it right now? If there is another move library that you would recommend, feel free to let me know. Thanks, Phil Deets II -- Using Opera's revolutionary e-mail client: http://www.opera.com/mail/

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