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[Boost.Log] Some few newbee questions
by Ovanes Markarian 10 Jul '13

10 Jul '13

Hi *, Thanks for the really great logging library. Just used it a bit and was amazed how useful and easy to use it was. As I start using it more and more I have some questions... 1. In my application I would like to start with the trivial logger and extend this logger with more options, i.e. attributes etc. Currently I see the following input when doing a trace: [2013-07-03 22:17:32.462265] [0x76f73180] [trace] thread_pool: creating 1 threads[2013-07-03 22:17:32.462303] [0x76f73180] [trace] thread_pool: created thread number: 1[2013-07-03 22:17:32.462312] [0x76f73180] [trace] thread_pool: all threads started[2013-07-03 22:17:32.462320] [0x76f73180] [trace] thread_pool: constructor finished My question is what is the second attribute? Thread id? As my code runs on a 64bit machine, that does not seem to be an address... 2. Is it possible to use a scoped logging with the trivial logger? I tried to do it as described in the example but see not output. How can I produce the output from the scoped logger? 3. In my example I wrote thread_pool prefix before each log entry. Can I do it automatically? How would I go on if I only have trivial logging? May be I misunderstand some concepts, like how to use multiple loggers and connect them with each other? Any help is very appreciated. Thanks, Ovanes

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Re: [Boost-users] Mutex synchronised wrapper class for boost::interprocess vector of strings
by Riskybiz 09 Jul '13

09 Jul '13

"It's not an easy task. You should catch the exception and then notify all connected processes that should disconnected from the segment (as only offline growing is supported). After that a process can call "grow" to try extend the segment. Then, all processes can attach to the newly grown segment. Think of that as a complex binary file that must be extended and internal structures changed. All users should close the file, the file should be changed by a process and then all users can start using the file again." OK Ion, thank you for that, I see.... 1. Can I ask what mechanism you would suggest for notifying the other processes to disconnect before the grow() operation? 2. Considering how to deal with the issue of dynamically growing a shared memory vector where there is one producer process and several consumers; I hit upon the notion of having the producer process use a std::vector to conventionally store data and then using a boost shared memory segment to store a pointer to the std::vector. Consumer processes would access the boost shared memory to retrieve the pointer value thus enabling access to the std::vector data store in the producer process. This, I hoped, might remove the complexities associated with dynamically growing a shared memory segment? The big question is: would it work? Would this be a valid means of interprocess communication? Or fraught with complexities? Thanks, Riskybiz.

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[msm] interrupt_state with more then one event that ends interrupt?
by Alexander Mingalev 09 Jul '13

09 Jul '13

Hi, Subj, Is that possible? for example, one event continues processing, the another one finishes the whole state-machine (some clean-up actions etc). I tried struct Interrupt : public msmf::interrupt_state< boost::mpl::vector<Foo, Bar> > {}; and struct Interrupt : public msmf::interrupt_state< msmf::ActionSequence_< boost::mpl::vector<Foo, Bar> > > {}; - has no effect. Is there another way to achieve this?

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[msm] interrupt_state with more then one event that ends interrupt?
by Sam Fisher 09 Jul '13

09 Jul '13

Hi, Subj, Is that possible? for example, one event continues processing, the another one finishes the whole state-machine (some clean-up actions etc). I tried struct Interrupt : public msmf::interrupt_state< boost::mpl::vector<Foo, Bar> > {}; and struct Interrupt : public msmf::interrupt_state< msmf::ActionSequence_< boost::mpl::vector<Foo, Bar> > > {}; - has no effect. Is there another way to achieve this?

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Boost.MultiIndex template substitution failure?
by fredbaba 08 Jul '13

08 Jul '13

I'm attempting to use boost::multi_index_container and it seems to be choking on the template metaprogramming magic somewhere. I'm getting a massive error dump ending in: /opt/local/include/boost/multi_index/hashed_index.hpp:743:9: error: ‘class boost::multi_index::detail::hashed_index, boost::hash, std::equal_to, boost::multi_index::detail::nth_layer<1, boost::intrusive_ptr, boost::multi_index::indexed_by >, boost::multi_index::ordered_non_unique, &md::Order::px> > >, std::allocator > >, boost::mpl::vector0, boost::multi_index::detail::hashed_unique_tag>’ has no member named ‘final_delete_node_’ this->final_delete_node_( I'm using Boost 1.53 (MacPorts) on Mac OS X.8 Mountain Lion. How do I get the following code to compile? Thanks. p.s. I originally posted this question on StackOverflow <http://stackoverflow.com/questions/17536227/boost-multiindex-template-subst…> but thought this might be a better forum. Sorry for the cross-post... #include <boost/multi_index_container.hpp> #include <boost/multi_index/hashed_index.hpp> #include <boost/multi_index/mem_fun.hpp> #include "Product.hpp" #include <iostream> int main(int argc, char* argv[]) { boost::multi_index_container< boost::intrusive_ptr<Product>, boost::multi_index::indexed_by< boost::multi_index::hashed_unique< boost::multi_index::const_mem_fun< Product, id_t, static_cast<id_t (Product::*)() const>(&Product::id) > >, boost::multi_index::ordered_non_unique< boost::multi_index::const_mem_fun< Product, price_t, static_cast<price_t (Product::*)() const>(&Product::price) > > > > cont; auto o = boost::intrusive_ptr<Product>(new Product()); o->id(1).price(price_t(14.75)); cont.insert(o); auto it = cont.get<1>().find(price_t(14.75)); if (it!=cont.get<1>().end()) std::cout << *(it); return 0; } -- View this message in context: http://boost.2283326.n4.nabble.com/Boost-MultiIndex-template-substitution-f… Sent from the Boost - Users mailing list archive at Nabble.com.

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Incorrect result from mcgregor_common_subgraphs. Where can I find more example of this MCS solver?
by dante0125 08 Jul '13

08 Jul '13

Hi, I am a beginner with BGL. Currently I am using mcgregor_common_subgraphs solver to find all the common subgraphs between two graphs. The following link is the only one example showing how to use the library that I can find from the Internet. http://svn.kulitorum.com/RepSnapper/Libraries/Boost1.40/libs/graph/example/… My first question is where can I find more example of this MCS solver? My second question is why some times it can not find maximum common subgraph. By maximum I mean a common subgraph with largest number of vertices which is implemented in the code. Here I provide an example. This code is modified from mcgregor_subgraphs_example, I change the graph to undirected graph and add some vetices and edges. It is obvious that the correct answer should be of size 9. The answer return by the code missing edge 8-5 and 8-3. //======================================================================= // Copyright 2009 Trustees of Indiana University. // Authors: Michael Hansen // // Distributed under the Boost Software License, Version 1.0. (See // accompanying file LICENSE_1_0.txt or copy at // http://www.boost.org/LICENSE_1_0.txt) //======================================================================= #include <fstream> #include <iostream> #include <string> #include <boost/lexical_cast.hpp> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/filtered_graph.hpp> #include <boost/graph/graph_utility.hpp> #include <boost/graph/iteration_macros.hpp> #include <boost/graph/mcgregor_common_subgraphs.hpp> #include <boost/property_map/shared_array_property_map.hpp> using namespace boost; // Callback that looks for the first common subgraph whose size // matches the user's preference. template <typename Graph> struct example_callback { typedef typename graph_traits<Graph>::vertices_size_type VertexSizeFirst; example_callback(const Graph& graph1) : m_graph1(graph1) { } template <typename CorrespondenceMapFirstToSecond, typename CorrespondenceMapSecondToFirst> bool operator()(CorrespondenceMapFirstToSecond correspondence_map_1_to_2, CorrespondenceMapSecondToFirst correspondence_map_2_to_1, VertexSizeFirst subgraph_size) { // Fill membership map for first graph typedef typename property_map<Graph, vertex_index_t>::type VertexIndexMap; typedef shared_array_property_map<bool, VertexIndexMap> MembershipMap; MembershipMap membership_map1(num_vertices(m_graph1), get(vertex_index, m_graph1)); fill_membership_map<Graph>(m_graph1, correspondence_map_1_to_2, membership_map1); // Generate filtered graphs using membership map typedef typename membership_filtered_graph_traits<Graph, MembershipMap>::graph_type MembershipFilteredGraph; MembershipFilteredGraph subgraph1 = make_membership_filtered_graph(m_graph1, membership_map1); // Print the graph out to the console std::cout << "Found common subgraph (size " << subgraph_size << ")" << std::endl; print_graph(subgraph1); std::cout << std::endl; // Explore the entire space return (true); } private: const Graph& m_graph1; VertexSizeFirst m_max_subgraph_size; }; int main (int argc, char *argv[]) { // Using a vecS graph here so that we don't have to mess around with // a vertex index map; it will be implicit. typedef adjacency_list<listS, vecS, undirectedS, property<vertex_name_t, unsigned int, property<vertex_index_t, unsigned int> >, property<edge_name_t, unsigned int> > Graph; typedef graph_traits<Graph>::vertex_descriptor Vertex; typedef graph_traits<Graph>::edge_descriptor Edge; typedef property_map<Graph, vertex_name_t>::type VertexNameMap; typedef property_map<Graph, edge_name_t>::type EdgeNameMap; // Test maximum and unique variants on known graphs Graph graph_simple1, graph_simple2; example_callback<Graph> user_callback(graph_simple1); VertexNameMap vname_map_simple1 = get(vertex_name, graph_simple1); VertexNameMap vname_map_simple2 = get(vertex_name, graph_simple2); // Graph that looks like a triangle put(vname_map_simple1, add_vertex(graph_simple1), 1); put(vname_map_simple1, add_vertex(graph_simple1), 2); put(vname_map_simple1, add_vertex(graph_simple1), 3); put(vname_map_simple1, add_vertex(graph_simple1), 4); put(vname_map_simple1, add_vertex(graph_simple1), 5); put(vname_map_simple1, add_vertex(graph_simple1), 6); put(vname_map_simple1, add_vertex(graph_simple1), 7); put(vname_map_simple1, add_vertex(graph_simple1), 8); put(vname_map_simple1, add_vertex(graph_simple1), 9); add_edge(0, 1, graph_simple1); add_edge(0, 2, graph_simple1); add_edge(0, 4, graph_simple1); add_edge(1, 2, graph_simple1); add_edge(1, 3, graph_simple1); add_edge(1, 6, graph_simple1); add_edge(2, 3, graph_simple1); add_edge(2, 4, graph_simple1); add_edge(3, 5, graph_simple1); add_edge(4, 5, graph_simple1); add_edge(5, 6, graph_simple1); add_edge(7, 8, graph_simple1); add_edge(6, 7, graph_simple1); add_edge(8, 5, graph_simple1); add_edge(8, 3, graph_simple1); std::cout << "First graph:" << std::endl; print_graph(graph_simple1); std::cout << std::endl; // Triangle with an extra vertex put(vname_map_simple2, add_vertex(graph_simple2), 1); put(vname_map_simple2, add_vertex(graph_simple2), 2); put(vname_map_simple2, add_vertex(graph_simple2), 3); put(vname_map_simple2, add_vertex(graph_simple2), 4); put(vname_map_simple2, add_vertex(graph_simple2), 5); put(vname_map_simple2, add_vertex(graph_simple2), 6); put(vname_map_simple2, add_vertex(graph_simple2), 7); put(vname_map_simple2, add_vertex(graph_simple2), 8); put(vname_map_simple2, add_vertex(graph_simple2), 9); add_edge(0, 1, graph_simple2); add_edge(0, 2, graph_simple2); add_edge(0, 4, graph_simple2); add_edge(1, 2, graph_simple2); add_edge(1, 5, graph_simple2); add_edge(2, 4, graph_simple2); add_edge(3, 5, graph_simple2); add_edge(3, 6, graph_simple2); add_edge(7, 8, graph_simple2); add_edge(1, 6, graph_simple2); add_edge(6, 7, graph_simple2); add_edge(8, 5, graph_simple2); add_edge(8, 3, graph_simple2); std::cout << "Second graph:" << std::endl; print_graph(graph_simple2); std::cout << std::endl; // Maximum subgraphs // Maximum, unique subgraphs std::cout << "mcgregor_common_subgraphs_unique:" << std::endl; mcgregor_common_subgraphs_unique (graph_simple1, graph_simple2, true, user_callback, vertices_equivalent(make_property_map_equivalent(vname_map_simple1, vname_map_simple2))); std::cin.get(); return 0; } -- View this message in context: http://boost.2283326.n4.nabble.com/Incorrect-result-from-mcgregor-common-su… Sent from the Boost - Users mailing list archive at Nabble.com.

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Re: [Boost-users] boost::io_service run() never returns
by Marat Abrarov 07 Jul '13

07 Jul '13

Not sure if this can help, but there was a problem with serial port (asynchronous reading, maybe epoll-related) at Ubuntu. That problem wasn't related to Asio, it was an OS bug. Search asio-users mailing list for details. Regards, Marat Abrarov.

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Different behavior of boost::serialization of strings on text archive
by Andrea Ranieri 07 Jul '13

07 Jul '13

Hi all, I'm having some issue serializing a `std::string` with `boost::serialization` on a `text_oarchive`. AFAICT, I have two identical pieces of code that behaves differently in two different programs. This is the program that I believe is behaving correctly: #include <iostream> #include <string> #include <sstream> #include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> template <typename T> void serialize_deserialize(const T & src, T & dst) { std::string serialized_data_str; std::cout << "original data: " << src << std::endl; std::ostringstream archive_ostream; boost::archive::text_oarchive oarchive(archive_ostream); oarchive << src; serialized_data_str = archive_ostream.str(); std::cout << "serialized data: " << serialized_data_str << std::endl; std::istringstream archive_istream(serialized_data_str); boost::archive::text_iarchive iarchive(archive_istream); iarchive >> dst; } int main() { std::string archived_data_str = "abcd"; std::string restored_data_str; serialize_deserialize<std::string>(archived_data_str, restored_data_str); std::cout << "restored data: " << restored_data_str << std::endl; return 0; } And this is its output: original data: abcd serialized data: 22 serialization::archive 10 4 abcd restored data: abcd (You can compile it with: `g++ boost-serialization-string.cpp -o boost-serialization-string -lboost_serialization`) This one, on the other hand, is an excerpt of the program I'm writing (derived from [boost_asio/example/serialization/connection.hpp][1]) that serializes `std::string` data converting each character in its hex representation: /// Asynchronously write a data structure to the socket. template <typename T, typename Handler> void async_write(const T& t, Handler handler) { // Serialize the data first so we know how large it is. std::cout << "original data: " << t << std::endl; std::ostringstream archive_stream; boost::archive::text_oarchive archive(archive_stream); archive << t; outbound_data_ = archive_stream.str(); std::cout << "serialized data: " << outbound_data_ << std::endl; [...] And this is an excerpt of its output: original data: abcd serialized data: 22 serialization::archive 10 5 97 98 99 100 0 The version (`10`) is the same, right? So that should be the proof that I'm using the same serialization library in both programs. However, I really can't figure out what's going on here. I've been trying to solve this puzzle for almost an entire work day now, and I'm out of ideas. For anyone that may want to reproduce this result, it should be sufficient to download the [Boost serialization example][2], add the following line connection_.async_write("abcd", boost::bind(&client::handle_write, this, boost::asio::placeholders::error)); at line 50 of `client.cpp`, add the following member function in client.cpp /// Handle completion of a write operation. void handle_write(const boost::system::error_code& e) { // Nothing to do. The socket will be closed automatically when the last // reference to the connection object goes away. } add this `cout`: std::cout << "serialized data: " << outbound_data_ << std::endl; at `connection.hpp:59` and compile with: g++ -O0 -g3 client.cpp -o client -lboost_serialization -lboost_system g++ -O0 -g3 server.cpp -o server -lboost_serialization -lboost_system I'm using `g++ 4.8.1` under `Ubuntu 13.04 64bit` with `Boost 1.53` Any help would be greatly appreciated. Best regards Avio P.s. I'm posting this because the deserialization of the `std::string`s isn't working at all! :) [1]: http://www.boost.org/doc/libs/1_53_0/doc/html/boost_asio/example/serializat… [2]: http://www.boost.org/doc/libs/1_53_0/doc/html/boost_asio/examples.html#boos…

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boost::io_service run() never returns
by shunguang 06 Jul '13

06 Jul '13

I have the following simplified code to read data from a RS232 port. For some (from beginning) runs, io.run() returns immediately and m_handler() is called which is expected. but sometimes (a fresh run from beginning), io.run() goes into a inside forever loop(stacked inside forever) even for the first time called inside the while loop. And this happens randomly. What's is/are the potential problem(s) at here? Thanks. -shunguang #define BUF_SIZE 512 char data[BUF_SIZE]; void my_handler(const boost::system::error_code& err, std::size_t bytes_transferred) { printf("%d\n", bytes_transferred); if (!err){ process_data(); } } void test_serial_port( int argc, char* argv[] ) { // hard coded parameters const char *PORT = "COM1"; serial_port_base::baud_rate BAUD(9600); serial_port_base::character_size CSIZE( 8 ); serial_port_base::flow_control FLOW( serial_port_base::flow_control::software ); serial_port_base::parity PARITY( serial_port_base::parity::none ); serial_port_base::stop_bits STOP( serial_port_base::stop_bits::one ); io_service io; serial_port port( io, PORT ); // go through and set all the options as we need them // all of them are listed, but the default values work for most cases port.set_option( BAUD ); port.set_option( CSIZE ); port.set_option( FLOW ); port.set_option( PARITY ); port.set_option( STOP ); while( !kbhit() ) { io.reset(); port.async_read_some( boost::asio::buffer(data, BUF_SIZE), boost::bind(&my_handler, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred ) ); io.run(); Sleep(300); } } -- View this message in context: http://boost.2283326.n4.nabble.com/boost-io-service-run-never-returns-tp464… Sent from the Boost - Users mailing list archive at Nabble.com.

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[filesystem] current_path
by Ovanes Markarian 06 Jul '13

06 Jul '13

Hello *, I need to create a relative symlink. To do so I currently use current_path function: auto current_path = fs::current_path(); BOOST_SCOPE_EXIT(&current_path) { fs::current_path(current_path); }BOOST_SCOPE_EXIT_END fs::current_path(some_base_path_here); fs::create_symlink ( fs::path("..")/some_subdirectory/image_name.filename() , original_name.filename() ) ; Is there any better way to create a relative symlink? What happens if I call current_path(whatever) in a multi-threaded environment? Is it thread-safe or should I synchronize the access to it? Many thanks, Ovanes

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