June 2014 - 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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[Range, Phoenix] What am I missing...
by Robert Jones 25 Apr '17

25 Apr '17

Hi Folks Can anyone explain the output of this program... #include <iostream> #include <boost/range/algorithm/copy.hpp> #include <boost/range/counting_range.hpp> #include <boost/range/adaptor/reversed.hpp> #include <boost/range/adaptor/transformed.hpp> #include <boost/phoenix/bind/bind_function.hpp> #include <boost/phoenix/core/argument.hpp> int f( int i ) { return i * 2; } int main( ) { using boost::adaptors::reversed; using boost::adaptors::transformed; using boost::counting_range; using boost::copy; using boost::phoenix::arg_names::_1; copy( counting_range( 1, 5 ) | reversed | transformed( f ), std::ostream_iterator<int>( std::cout, " " ) ); std::cout << std::endl; copy( counting_range( 1, 5 ) | reversed | transformed( bind( f, _1 ) ), std::ostream_iterator<int>( std::cout, " " ) ); std::cout << std::endl; } Which is... 8 6 4 2 1768406272 1768406272 1768406272 1768406272 I'm using Gcc 4.6.2 & Boost 1.53 Thx All.

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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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Re: [Boost-users] lexical_cast between double and string slow in Visual Studio 2013
by David Roberts 07 May '15

07 May '15

> That issue is unknown. I'd really appreciate the investigation. I have done some more investigation, and there are two factors that only cause the slowness when they both occur together. > Try excluding the lexical_cast from test, I have a feeling that this is only MSVC related issue: > > #include <sstream> > #include <string> > > int main (int, char **) > { > for (double count = 0.0; count < 1000000.0; count += 1.41) > { > std::stringstream ss; > ss << count; > std::string result = std::move(ss.str()); > ss.str(std::string()); > > ss << result; > ss >> count; > } > > return 0; > } > Running your test program does not exhibit the problem. It runs in around 3 seconds on my machine when built with either Visual Studio 2010 or Visual Studio 2013. However, changing it very slightly to match more closely what lexical_cast does internally does recreate the problem: #include <sstream> #include <string> int main (int, char **) { for (double count = 0.0; count < 1000000.0; count += 1.41) { std::stringstream ss; ss.unsetf(std::ios::skipws); ss.precision(17); ss << count; std::string result = std::move(ss.str()); ss.str(std::string()); ss << result; ss >> count; } return 0; } The effect of setting the precision to 17 is that lots of 9s appear in the string representations. (The number 17 is what boost::detail::lcast_get_precision(double*) chooses.) Without the precision call the contents of the string called result start off like this: 0 1.41 2.82 4.23 5.64 7.05 8.46 9.87 11.28 12.69 With precision set to 17 they start off like this: 0 1.4099999999999999 2.8199999999999998 4.2299999999999995 5.6399999999999997 7.0499999999999998 8.4599999999999991 9.8699999999999992 11.279999999999999 12.69 This happens for both Visual Studio 2010 and Visual Studio 2013. Then the next difference is that Visual Studio 2013 spends a lot longer handling all the extra 9s. Changing the program so that the double is converted to a string using std::stringstream without a precision call and then back to double using lexical_cast takes about 3 seconds for both Visual Studio 2010 and Visual Studio 2013. It is the combination of having all the extra 9s to parse and using Visual Studio 2013 that makes the test using lexical_cast to go both ways slow. Both Visual Studio 2010 and Visual Studio 2013 do the conversion by calling std::num_get<char,std::istreambuf_iterator<char,std::char_traits<char> > >::do_get() which then calls a function called _Stodx() which is implemented in xstod.c. This function is very different for the two versions. In Visual Studio 2010 it's a relatively thin wrapper around the C function strtod(). In Visual Studio 2013 _Stodx() has got a completely new implementation that's generated by #including xxstod.h with some macros defined. The original C function strtod() is much faster than the new _Stodx() when there are lots of 9s at the end of the strings being parsed. This modification to the program: #include <sstream> #include <string> #include <stdlib.h> int main (int, char **) { for (double count = 0.0; count < 1000000.0; count += 1.41) { std::stringstream ss; ss.unsetf(std::ios::skipws); ss.precision(17); ss << count; std::string result = std::move(ss.str()); ss.str(std::string()); ss << result; char *endptr; count = strtod(ss.str().c_str(), &endptr); } return 0; } has a runtime of about 3 seconds even though it's got to cope with all the 9s. I guess only someone from Microsoft or Dinkumware could comment on why _Stodx() was reimplemented. But the other thing is that by setting precision to 17 lexical_cast is bloating the string representations of the doubles with lots of 9s in both Visual Studio 2010 and Visual Studio 2013. Setting precision to 15 instead prevents this, and makes the original test run faster even with Visual Studio 2013 (about 4 seconds rather than 10). Regards, David

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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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NT² 3.0 and Boost.SIMD - Stable release
by Joel Falcou 21 Nov '14

21 Nov '14

The first stable release of the 3.x series of MetaScale’s open-source software is available: NT² 3.0. It also includes its spin-off project, Boost.SIMD (not yet a Boost library). Many Issues have been closed since last beta. The main focus of this release cycle was to fix performances issues and to stabilize some parts of the API. Next step will be to separate NT2 and Boost.SIMD into separate repositories, thus making one more step toward Boost.SIMD submission into review. [ http://www.metascale.org/nt%C2%B2-3-0-and-boost-simd ] *Changes & Bug Fixes:* - Major performance improvements in both libraries - Added experimental support for the HPX runtime for parallelization on shared memory systems - Optimizations of many elemental functions, in particuler log/ex, frexp/ldexp and cbrt - More advanced shuffle pattern recognition for SIMD - Fixed issues with Visual Studio 2013 - More functions are force-inlined to ensure good performance - New functions for conversion between types and mixing of vectors of different sizes - Demo applications usable as benchmarks - Better handling of errors when an unsupported function is called - New API for custom memory allocators Full changelog is available at https://github.com/MetaScale/nt2/releases/tag/3.0.0. *How to get it ?* - Source and binary packages can be downloaded here: http://nt2.metascale.org/downloads - The release is also available on Github : https://github.com/MetaScale/nt2/releases - The main master branch is still under development : https://github.com/MetaScale/nt2

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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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[Log] Extract severity value
by Olivier Tournaire 17 Jul '14

17 Jul '14

Hi all, I am trying to extract severity level from a log record, but i seems that I am doing it the wrong way. Here is the code I use: void LogDockWidget::receiveLog(boost::log::record_view const& rec, const std::string& log) { logging::value_ref< logging::trivial::severity_level > level = logging::extract< logging::trivial::severity_level >("Severity", rec); // ... } Here level.get() always returns "info". All my logs are done with the BOOST_LOG_TRIVIAL(...) macro. The formatter whereas displays correctly the severity level. Here is how it is defined: void LogDockWidget::init_logging() { boost::shared_ptr< logging::core > core = logging::core::get(); typedef sinks::synchronous_sink< QTextEditFormattedSinkBackend > sink_t; boost::shared_ptr< sink_t > sink(new sink_t); // ... logging::add_file_log( keywords::file_name = logFilename, keywords::auto_flush = true, keywords::format = ( BUILD_LOG_FORMATTER() ) ); sink->set_formatter( BUILD_LOG_FORMATTER() ); core->add_sink(sink); // Add attributes that we will use logging::add_common_attributes(); core->add_global_attribute( "ThreadID", attrs::current_thread_id()); } #define BUILD_LOG_FORMATTER() \ expr::stream \ << "[" << expr::format_date_time< boost::posix_time::ptime >("TimeStamp", "%Y-%m-%d %H:%M:%S") << "] " \ << expr::attr<unsigned int>("LineID") << " " \ << ": <" << logging::trivial::severity << "> " \ << " [" << expr::attr<attrs::current_thread_id::value_type>("ThreadID") << "] " \ << expr::if_(expr::has_attr(scope_attribute)) \ [ \ expr::stream << "[" << scope_attribute << "] " \ ] \ << expr::message Could you please let me know what I am doing wrong? Regards, Olivier

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[spirit] qi xml parser
by Michael Powell 07 Jul '14

07 Jul '14

Hello, I am building out a general use xml parser including attributes, arbitrary number of elements, and so on. So far so good, makes sense parsing names and so forth. However, how do you handle element content? Which could either be a string, or zero or more other elements (basically of the same rule as the enclosing element rule). It would seem you need a terminus, the empty element tag. In such a way that populates the parent (initial) element, and its children (of the same element kind). I'll be adapting structs to capture the results. I am also using a couple of helpful references, for instance: http://www.w3.org/TR/xml11/ http://stackoverflow.com/questions/9473843/boost-spirit-how-to-extend-xml-p… Also not sure quite how to capture the adapted parts at strategic rule opportunities. My domain model will look something like this, keeping it simple as possible: struct xattribute { std::string name; std::string value; }; typedef std::vector<xattribute> xattribute_vector; struct xelement; typedef std::vector<xelement> xelement_vector; struct xelement { std::string name; std::string content; xattribute_vector attributes; xelement_vector children; }; Thanks... Best regards, Michael Powell

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[Graph] Newbie on A*
by Sensei 04 Jul '14

04 Jul '14

Dear all, I am fiddling with the A* example on cities in order to learn how to use the A* search. Obviously, I cannot make it work :) The main goal is this, but I'm way too far from this: make A* fail when the path is longer, **not costlier**, than a constant. But right now I'd just like to have A* working on a graph. :) In order to see the different results, I've paired it with a Dijkstra search, and my A* heuristics is quite simple: constant. Dijkstra works fine, but A* stops at the first node, and the target isn't reached (but a path is available). What am I doing wrong? Forgive me if I'm making a stupid mistake bu I'm completely a newbie! If you need the graph, here's the link: https://dl.dropboxusercontent.com/u/15635416/g.txt Thanks! #include <cstdio> #include <cstdlib> #include <iostream> #include <utility> #include <algorithm> #include <numeric> #include <deque> #include <unordered_set> #include <vector> #include <fstream> #include <list> #include <boost/graph/graph_traits.hpp> #include <boost/graph/compressed_sparse_row_graph.hpp> #include <boost/graph/dijkstra_shortest_paths.hpp> #include <boost/graph/breadth_first_search.hpp> #include <boost/graph/depth_first_search.hpp> #include <boost/pending/indirect_cmp.hpp> #include <boost/range/irange.hpp> #include <boost/property_map/property_map.hpp> #include <boost/graph/astar_search.hpp> // Properties: weights are int typedef boost::property<boost::edge_weight_t, int> edge_weight; // The graph itself as a compressed sparse row matrix typedef boost::compressed_sparse_row_graph<boost::bidirectionalS, boost::no_property, edge_weight> boost_graph; // Vertex iterator typedef boost::graph_traits<boost_graph>::vertex_iterator vertex_iterator; // Edge iterator typedef boost::graph_traits<boost_graph>::edge_iterator edge_iterator; // Adjacent nodes iterator typedef boost::graph_traits<boost_graph>::adjacency_iterator adjacency_iterator; typedef boost::graph_traits<boost_graph>::out_edge_iterator outward_iterator; typedef boost::graph_traits<boost_graph>::in_edge_iterator inward_iterator; // Property maps typedef boost::property_map<boost_graph, boost::vertex_index_t>::type index_map; //typedef boost::property_map<boost_graph, boost::vertex_name_t> name_map; // Property iterators typedef boost::iterator_property_map<std::size_t*, index_map, std::size_t, std::size_t&> predecessor_map; typedef boost::iterator_property_map<std::size_t*, index_map, std::size_t, std::size_t&> distance_map; bool isValid(std::size_t index) { return (index >= 0) && (index <= 12); } // **************************************************************************** // A* heuristics template <class graph_type> class astar_heuristic : public boost::astar_heuristic<graph_type, std::size_t> { public: typedef typename boost::graph_traits<graph_type>::vertex_descriptor vertex_type; astar_heuristic(vertex_type goal) : goal_(goal) { }; std::size_t operator()(vertex_type u) { return 3; } private: vertex_type goal_; }; // Class to be used to terminate the A* algorithm class exit_astar { public: exit_astar(bool found) { }; }; // A* visitor that terminates when we find the goal template <class vertex_type> class astar_visitor : public boost::default_astar_visitor { public: astar_visitor(vertex_type goal) : goal_(goal) { }; template <class Graph> void examine_vertex(vertex_type u, Graph& g) { //std::cout << "EXAM: " << u << std::endl; if (u == goal_) throw exit_astar(true); } private: vertex_type goal_; }; // **************************************************************************** int main(int argc, const char * argv[]) { std::vector<std::pair<std::size_t, std::size_t>> graph_edges; std::vector<int> edge_weight; int n_nodes; int read_a, read_b, read_w; n_nodes = -1; std::ifstream igraph("/Users/senseiwa/Documents/Projects/scratch/tbb/g.txt"); while(igraph >> read_a >> read_b >> read_w) { if (read_a > n_nodes) n_nodes = read_a; if (read_b > n_nodes) n_nodes = read_b; read_a--; read_b--; graph_edges.push_back(std::make_pair(read_a, read_b)); edge_weight.push_back(read_w); } std::cout << "+++ READ # NODES: " << n_nodes << std::endl; // Create the graph boost_graph graph(boost::edges_are_unsorted_multi_pass, graph_edges.begin(), graph_edges.end(), edge_weight.data(), n_nodes); std::cout << "Graph statistics: " << std::endl; std::cout << "Nodes: " << boost::num_vertices(graph) << std::endl; std::cout << "Edges: " << graph_edges.size() << std::endl; edge_iterator ei, ee; std::size_t source_node = std::stoul(argv[1]); std::size_t destination_node = std::stoul(argv[2]); std::cout << ">> SOURCE NODE " << source_node << std::endl; std::cout << "Degrees in/out: " << source_node << std::endl; std::cout << boost::in_degree(boost::vertex(source_node, graph), graph) << std::endl; std::cout << boost::out_degree(boost::vertex(source_node, graph), graph) << std::endl; std::cout << "Degrees in/out: " << destination_node << std::endl; std::cout << boost::in_degree(boost::vertex(destination_node, graph), graph) << std::endl; std::cout << boost::out_degree(boost::vertex(destination_node, graph), graph) << std::endl; std::vector<std::size_t> preds(boost::num_vertices(graph)); std::vector<std::size_t> dists(boost::num_vertices(graph)); index_map idx_map = boost::get(boost::vertex_index, graph); predecessor_map pred_map(preds.data(), idx_map); distance_map dist_map(dists.data(), idx_map); boost::dijkstra_shortest_paths(graph, source_node, boost::distance_map(dist_map).predecessor_map(pred_map)); typedef std::vector<boost_graph::edge_descriptor> path_type; path_type spath; std::cout << ">> SOURCE NODE " << source_node << std::endl; std::cout << ">> DESTINATION NODE " << destination_node << std::endl; // ******* DIJKSTRA ******************************************************** std::size_t v = destination_node; // We want to start at the destination and work our way back to the source for(std::size_t u = pred_map[v]; // Start by setting 'u' to the destintaion node's predecessor u != v; // Keep tracking the path until we get to the source v = u, u = pred_map[v]) // Set the current vertex to the current predecessor, and the predecessor to one level up { std::pair<boost_graph::edge_descriptor, bool> edgePair = boost::edge(u, v, graph); boost_graph::edge_descriptor edge = edgePair.first; spath.push_back(edge); } // Write shortest path int totalDistance = 0; for(path_type::reverse_iterator pathIterator = spath.rbegin(); pathIterator != spath.rend(); ++pathIterator) { std::cout << boost::source(*pathIterator, graph) << " - " << boost::target(*pathIterator, graph) << " = " << boost::get(boost::edge_weight, graph, *pathIterator) << std::endl; totalDistance += boost::get(boost::edge_weight, graph, *pathIterator); } std::cout << "Shortest Dijkstra path from " << source_node << " to " << destination_node << " cost " << totalDistance << std::endl; // ******* A* ************************************************************** // A* search predecessor and cost std::vector<std::size_t> p(boost::num_vertices(graph)); std::vector<std::size_t> d(boost::num_vertices(graph)); try { // A* parameter interface astar_search(graph, source_node, astar_heuristic<boost_graph>(destination_node), boost::predecessor_map(&p[0]).distance_map(&d[0]).visitor(astar_visitor<std::size_t>(destination_node))); } catch(exit_astar fg) { std::list<std::size_t> shortest_path; for(std::size_t v = source_node; ; v = p[v]) { shortest_path.push_front(v); if(p[v] == v) break; } auto spi = shortest_path.begin(); std::cout << "node " << source_node << std::endl; for(++spi; spi != shortest_path.end(); ++spi) std::cout << "node " << *spi << std::endl; std::cout << "Shortest A* path from " << source_node << " to " << destination_node << " cost " << d[destination_node] << std::endl; std::cout << shortest_path.size() << std::endl; return 0; } std::cout << "Didn't find a path from " << source_node << "to" << destination_node << "!" << std::endl; return 0; } +++ READ # NODES: 200 Graph statistics: Nodes: 200 Edges: 4000 >> SOURCE NODE 1 Degrees in/out: 1 0 35 Degrees in/out: 192 39 1 >> SOURCE NODE 1 >> DESTINATION NODE 192 1 - 47 = 2 47 - 91 = 3 91 - 120 = 1 120 - 175 = 1 175 - 192 = 10 Shortest Dijkstra path from 1 to 192 cost 17 node 1 Shortest A* path from 1 to 192 cost 17 1

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Why does async_connect() call listen()?
by Soren Dreijer 01 Jul '14

01 Jul '14

Hi there, By coincidence, I ended up looking at a stack trace where my application calls async_connect() on a asio::ip::tcp::socket. Two things took me by surprise: 1. Asio calls listen() under the hood. Why does it do that when I'm just trying to make an outbound TCP connection? 2. If the listen() call above is indeed required, why does it happen on the same thread where I call async_connect()? I thought the point of the method was to defer the work to the reactor? (For what it's worth, I've had a case on a customer's machine where the call to listen() would hang for 30 seconds before returning -- probably because of a bad firewall -- causing my entire app to hang since the code assumes async_connect() is indeed async.) I've included the full stack trace below. Thanks, Soren 0:000> k ChildEBP RetAddr 0117db50 0f681c65 WS2_32!listen 0117db70 0f691013 EvoClr!boost::asio::detail::socket_ops::listen+0x35 [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\impl\socket_ops.ipp @ 658] 0117dbd8 0f690e9f EvoClr!boost::asio::detail::socket_select_interrupter::open_descriptors+0x163 [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\impl\socket_select_interrupter.ipp @ 78] 0117dbe4 0f690cc0 EvoClr!boost::asio::detail::socket_select_interrupter::socket_select_interrupter+0xf [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\impl\socket_select_interrupter.ipp @ 42] 0117dc1c 0f690c1e EvoClr!boost::asio::detail::select_reactor::select_reactor+0x70 [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\impl\select_reactor.ipp @ 48] 0117dc44 0f17837e EvoClr!boost::asio::detail::service_registry::create<boost::asio::detail::select_reactor>+0x4e [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\impl\service_registry.hpp @ 81] 0117dc80 0f6909e9 EvoClr!boost::asio::detail::service_registry::do_use_service+0x9e [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\impl\service_registry.ipp @ 123] 0117dca0 0f6908ee EvoClr!boost::asio::detail::service_registry::use_service<boost::asio::detail::select_reactor>+0x39 [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\impl\service_registry.hpp @ 49] 0117dca8 0f68fab0 EvoClr!boost::asio::use_service<boost::asio::detail::select_reactor>+0xe [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\impl\io_service.hpp @ 34] 0117dcbc 0f68f731 EvoClr!boost::asio::detail::win_iocp_socket_service_base::get_reactor+0x30 [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\impl\win_iocp_socket_service_base.ipp @ 620] 0117dce4 0f68f6f1 EvoClr!boost::asio::detail::win_iocp_socket_service_base::start_connect_op+0x11 [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\impl\win_iocp_socket_service_base.ipp @ 550] 0117dd28 0f68ed22 EvoClr!boost::asio::detail::win_iocp_socket_service<boost::asio::ip::tcp>::async_connect<boost::_bi::bind_t<void,boost::_mfi::mf1<void,Swift::BoostConnection,boost::system::error_code const &>,boost::_bi::list2<boost::_bi::value<boost::shared_ptr<Swift::BoostConnection> >,boost::arg<1> > > >+0xc1 [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\win_iocp_socket_service.hpp @ 515] 0117dd68 0f68c41a EvoClr!boost::asio::stream_socket_service<boost::asio::ip::tcp>::async_connect<boost::_bi::bind_t<void,boost::_mfi::mf1<void,Swift::BoostConnection,boost::system::error_code const &>,boost::_bi::list2<boost::_bi::value<boost::shared_ptr<Swift::BoostConnection> >,boost::arg<1> > > >+0x52 [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\stream_socket_service.hpp @ 234] 0117ddec 0f68a32e EvoClr!boost::asio::basic_socket<boost::asio::ip::tcp,boost::asio::stream_socket_service<boost::asio::ip::tcp> >::async_connect<boost::_bi::bind_t<void,boost::_mfi::mf1<void,Swift::BoostConnection,boost::system::error_code const &>,boost::_bi::list2<boost::_bi::value<boost::shared_ptr<Swift::BoostConnection> >,boost::arg<1> > > >+0x11a [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\basic_socket.hpp @ 779] 0117de9c 0f210146 EvoClr!Swift::BoostConnection::connect+0x11e [c:\private\src\vendor\swift\swiften\network\boostconnection.cpp @ 70]

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[atomic] ThreadSanitizer reports a data race when using the code from "reference counting" example
by Adam Romanek 01 Jul '14

01 Jul '14

Hi Boosters! I'd like to draw your attention to an issue with Boost.Atomic that I encountered when using ThreadSanitizer. The problem is that when using the code shown in "reference counting" example [1] from the docs, the ThreadSanitizer reports a data race. Everything is described in detail in a StackOverflow thread [2] so I don't want to repeat all that here. Please help me determine whether it's a false positive, an issue in Boost.Atomic or a wrong usage of the code. Additionally, I don't understand this: Write of size 1 at 0x7d040000f7f0 by thread T2: #0 operator delete(void*) <null>:0 (a.out+0x00000004738b) What kind of write does ThreadSanitizer might refer to? WBR, Adam Romanek [1] http://www.boost.org/doc/libs/1_55_0/doc/html/atomic/usage_examples.html#bo… [2] http://stackoverflow.com/questions/24446561/threadsanitizer-reports-data-ra…

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Oneshot fixture per test suit
by Florian Lindner 30 Jun '14

30 Jun '14

Hello, is it possible to have a test fixture that is created once per test suite and is destroyed after the last test of the test suite has been ran? A test suite level fixture is created before each and every test, a global fixture just once for the entire test programm. Thanks, Florian

1 0

Re: [Boost-users] [fusion] maps and arrays
by Seeger, Steven D. (GSFC-444.0)[Embedded Flight Systems, Inc] 29 Jun '14

29 Jun '14

From: Agust?n K-ballo Berg? Subject: Re: [Boost-users] [fusion] maps and arrays >Not an official answer in any way, but considering it's not explicitly >documented as supported and your test case also fails when replacing >`fusion::map` with `std::tuple` I would consider it just a fluke in the >past. On the other hand, the following code compiles correctly (albeit >with possibly a warning): Hi Agustin thanks for your reply. You are correct that what I'm doing is not documented. In fact, it doesn't really make sense now that I look at it. The for_each should be called on each type. If the type is an array it doesn't make sense for a for_each to break down the array. That said, there should be some way to specialize operator() in the functor passed to it in order to correctly handle array types. > typedef std::tuple<short, > int, > std::array<int, 2>, // note std::array > std::string > test_t; You inspired me with your use of std::array to try it out in my example. I changed "print_me" to use t.second instead of just t (which is correct) and then made a template function to support std::array with std::cout. That did the trick. Of course, the real goal here would be to handle it on the for_each side not the cout side, as outputting the types is not always the goal. > test_t test{1, 2, {}, {"hello"}}; You know one other weird thing, is that with boost 1.53 I could initialize this with std::array<int, 2> as: test_1 test{1,2, {{3,4}}, {"hello"}}; Now with 1.55 it's only working with: test_1 test{1,2,std::int<array, 2>{3, 4}, "hello"}; //missing braces on string correct I'm using both gcc 4.8.3 and clang 3.4.1. Steven

2 1

[thread] mutex is locked
by gast128 29 Jun '14

29 Jun '14

Dear all, does anybody know if there is a possibility to check if a mutex is locked? There is an 'owns_lock' on the lock type but not on the mutex. The main use case for me is debugging (and documentation) purposes: void MyClass::Process() { boost::unique_lock<boost::mutex> lck(m_mtx); ProcessImpl(); } void MyClass::ProcessImpl() { _ASSERT(m_mtx.is_locked()); //does not exist :( }

4 4

Selecting one element per fusion sequence using mpl::int_s
by gsermaid 29 Jun '14

29 Jun '14

Dear all, I am trying to create a fusion sequence whose elements are non-const references to the elements of given set of sequences. In particular, for a given sequence of integral constants, say vector< int_<2>, int_<1> >, and two fusion sequences, say X = vector< X0, X1, X2, X3 > and Y = vector< Y0, Y1, Y2 >, I would like to create the following sequence R = vector< X2&, Y1& >, such that at<0>(R) == at<2>(X) and at<1>(R) == at<1>(Y). I am using fusion::transform to achieve the above but the transform function takes the sequences as const references so I end up with R = vector<const X2&, const Y1&>, which is not what I want. Below is my code; any ideas on how to get a sequence of non-const references would be greatly appreciated. Thanks for reading! #include <boost/fusion/include/vector.hpp> #include <boost/fusion/include/transform.hpp> #include <boost/fusion/sequence/io/out.hpp> #include <boost/fusion/include/at.hpp> #include <boost/mpl/assert.hpp> #include <boost/type_traits.hpp> #include <iostream> using namespace boost::fusion; using boost::mpl::int_; using my_ints = vector< int_<2>, int_<1> >; using my_x = vector<int, double, unsigned, float>; using my_y = vector<unsigned, float, long>; using joined = vector<my_x, my_y>; struct my_functor { template <class I, class Seq> typename result_of::at<Seq, I>::type operator()(I& i, Seq& seq) const { return boost::fusion::at<I>(seq); } }; int main() { my_ints ints; my_x x(-2, 3.5, 15, -1.3); my_y y(4, 10.1, 100); joined jv(x, y); auto tv = transform(ints, jv, my_functor()); std::cout << tv << std::endl; // prints (15 10.1) // these two fail to compile because the first argument is const-qualified BOOST_MPL_ASSERT(( boost::is_same< decltype(at_c<0>(tv)), unsigned& > )); BOOST_MPL_ASSERT(( boost::is_same< decltype(at_c<1>(tv)), float& > )); }

2 1

[fusion] maps and arrays
by Seeger, Steven D. (GSFC-444.0)[Embedded Flight Systems, Inc] 28 Jun '14

28 Jun '14

I've had some code written with boost 1.53 a while ago that uses fusion maps to define at compile-time packet structures. There is then compile time generated code that handles marshaling, unmarshaling, and packet size calculation on these structures. One of the big reasons for going this route was the ability to have arrays contained in the packets. When upgrading from boost 1.53 to 1.55 on my Gentoo box, this all broke. I posted a bug report at https://svn.boost.org/trac/boost/ticket/10133 but it seems fusion bug reports don't get much activity here. I'm contacting the list to ask if the use of arrays in containers was just a fluke or if it should be working and something happened in 1.55 (or possibly 1.54 which I never tried.) If this is not something that should be supported then I will abandon this code and go with something else. It's been really nice to work on some client/server stuff with it because the work that went in to handle the code generation saves a lot of time going forward. Thanks, Steven

2 1

Boost.Coroutine with segmentation fault
by Van Pers 27 Jun '14

27 Jun '14

Hi all, I am writting a code with Coroutines lib, this code uses coroutines in a recursive way but when I create a large number of coroutines the program crashes (segmentation fault). I write a simplified version that reproduces this error: #include<iostream> #include<cstdlib> #include<boost/coroutine/all.hpp> #include <boost/bind.hpp> #include <boost/shared_ptr.hpp> class FClass{ private: int n; public: boost::coroutines::coroutine<void>::pull_type* startResume; FClass(int n) : n(n){ startResume = NULL; } void resume(){ if(startResume && *(startResume)) (*(startResume))(); } void doSomething ( boost::coroutines::coroutine< void >::push_type & fPause){ if (n > 2){ FClass* tc1 = new FClass(--n); tc1->startResume = new boost::coroutines::coroutine<void>::pull_type( boost::bind( &FClass::doSomething, tc1, _1) ); FClass* tc2 = new FClass(--n); tc2->startResume = new boost::coroutines::coroutine<void>::pull_type( boost::bind( &FClass::doSomething, tc2, _1) ); fPause(); tc1->resume(); tc2->resume(); } return; } }; int main(int argc, char** argv){ int max = 10; if (argc > 1){ max = atoi(argv[1]); } FClass* firstObject = new FClass (max) ; firstObject->startResume = new boost::coroutines::coroutine<void>::pull_type( boost::bind(&FClass::doSomething, firstObject, _1) ); firstObject->resume(); } gdb output reports:"memset () at ../sysdeps/x86_64/memset.S:78 ../sysdeps/x86_64/memset.S:No such file or directory." Anybody can help me? Regards, Van

1 0

core when using managed shared memory -- file based
by Sean K 27 Jun '14

27 Jun '14

I have a client and server set up where the client would write to the shared memory via a managed memory vector. And then the server would read that shared memory via the managed mapped file. It works for most situations. However, I just ran into a situation where the client -- writing to the vector, crashes. and I am trying to figure out what caused the crash. Below are the client (writer) and the server (reader) source code.... as close as to the current. Any insights as to why the vector.push_back() crashed? (this is happening on RH 5.9 64 bit OS.. but the code is compiled for 32 bit.) client: #include <iostream> #include <iostream> #include <string> #include <cstdlib> using namespace std; #include "fileheader.h" int main() { std::string data = "Hello"; char myinput[1024]; printf("enter number of count \n"); scanf("%s", &myinput); printf("You entered %s \n", myinput); data = myinput; int count = std::atoi(myinput); for (int counter = 0; counter < count; counter ++) { try { std::string tmpPath = "/var/tmp/log/testfile/ManagedMappedFile";; printf("temp directory: %s \n", tmpPath.c_str()); managed_mapped_file segment(open_or_create, tmpPath.c_str(), SHARED_MEMORY_SIZE); printf("initialized managed shared memory \n"); BString bstrData(segment.get_segment_manager()); bstrData = "hello world"; StrAllocator alloc_init(segment.get_segment_manager()); printf("ALLOCATED memory successfully\n"); BStrVector *myvec = segment.find_or_construct<BStrVector> (SHARED_VECTOR_NAME)(alloc_init); myvec->push_back(bstrData); segment.flush(); printf("inserted mystring into shmvector %d\n", counter); } catch (boost::interprocess::bad_alloc e) { printf("we caught bad alloc\n"); printf("explanation: %s\n", e.what()); printf("error code: %d\n", e.get_error_code()); printf("native: %d\n", e.get_native_error()); break; } catch (...) { printf("caught unknown exception\n"); } } printf("wrote number"); return 0; } contents of fileheader.h #ifndef FILEHEADER_H_ #define FILEHEADER_H_ #include <boost/interprocess/managed_shared_memory.hpp> #include <boost/interprocess/managed_mapped_file.hpp> #include <boost/thread/thread.hpp> #include <boost/interprocess/containers/vector.hpp> #include <boost/interprocess/containers/string.hpp> #include <boost/interprocess/allocators/allocator.hpp> #include <boost/interprocess/detail/tmp_dir_helpers.hpp> using namespace boost::interprocess; typedef boost::interprocess::managed_mapped_file::segment_manager segment_manager_t; typedef boost::interprocess::allocator<char, segment_manager_t> ShmemAllocator; typedef boost::interprocess::basic_string<char, std::char_traits<char>, ShmemAllocator> BString; typedef boost::interprocess::allocator<BString, segment_manager_t> StrAllocator; typedef boost::interprocess::vector<BString, StrAllocator> BStrVector; typedef std::pair<BString *, std::size_t> BStringPair; typedef std::pair<BStrVector *, std::size_t> BStrVectorPair; const char * SHARED_VECTOR_NAME = "MyVector"; const int SHARED_MEMORY_SIZE = 65536; #endif /* FILEHEADER_H_ */ g++ -m32 -fPIC -Xlinker -zmuldefs filewriter.cpp -o writer -I/cots/boost_1_42_0/include -L/cots/boost_1_42_0/lib -lboost_thread -lboost_system -pthread Server: #include <iostream> #include <string> #include <cstdlib> using namespace std; #include "../../filewriter/src/fileheader.h" int main() { int count = 0; std::string tmpPath = "/var/tmp/log/testfile"; //boost::interprocess::detail::get_tmp_base_dir(tmpPath); printf("temp directory: %s \n", tmpPath.c_str()); //boost::interprocess::detail::create_tmp_dir_and_get_filename("ManagedMappedFile", tmpPath); printf("temp file: %s \n", tmpPath.c_str()); // file_mapping::remove(tmpPath.c_str()); while (true) { try { managed_mapped_file segment(open_only, tmpPath.c_str()); if (segment.get_num_named_objects() > 0){ BStrVectorPair message = segment.find<BStrVector> (SHARED_VECTOR_NAME); printf("stuff in memory\n"); int size = message.first->size(); int retcode = 0; bool success=true; printf("PROCESS: Number of messages: %d\n", size); for (int imessage=0; imessage < size ; imessage++){ const char * const buffer = message.first->at(imessage).c_str(); int len = message.first->at(imessage).length(); printf("PROCESS: going to process this message: %s\n" , buffer); } printf("p.second: %d \n", message.second); segment.destroy<BStrVectorPair>(SHARED_VECTOR_NAME); } } catch (exception& e){ printf("exception %s", e.what()); } catch (...){ printf("unexpected exception"); } int msecs = 2000; boost::this_thread::sleep(boost::posix_time::milliseconds(msecs)); printf("sleeping...\n"); } return 0; } g++ -m32 -fPIC -Xlinker -zmuldefs filereader.cpp -o reader -I/cots/boost_1_42_0/include -L/cots/boost_1_42_0/lib -lboost_thread -lboost_system -pthread

1 0

Unexpected behavior when using as::ftime() of Boost Locale library
by Mouse Beer 27 Jun '14

27 Jun '14

Hi all, I see a mismatch when using %Y format specifier with as::ftime. It looks like it outputs the year according to the week of the year. I hope I didn't miss or misunderstand anything... please find my small test program attached for reference. It was compiled as follows: g++ -g -Wall -I /opt/boost/1.55/include -L /opt/boost/1.55/lib -lboost_locale -lboost_thread -lboost_system -licuuc -licui18n -licudata -lpthread -lrt boost_dates_test.cpp I am running on Debian Testing: $ ldd a.out linux-vdso.so.1 (0x00007fffa39fe000) libboost_locale.so.1.55.0 => /opt/boost/1.55/lib/libboost_locale.so.1.55.0 (0x00007fba3335b000) libboost_thread.so.1.55.0 => /opt/boost/1.55/lib/libboost_thread.so.1.55.0 (0x00007fba33142000) libboost_system.so.1.55.0 => /opt/boost/1.55/lib/libboost_system.so.1.55.0 (0x00007fba32f3e000) libicuuc.so.52 => /usr/lib/x86_64-linux-gnu/libicuuc.so.52 (0x00007fba32ba2000) libicui18n.so.52 => /usr/lib/x86_64-linux-gnu/libicui18n.so.52 (0x00007fba3279a000) libicudata.so.52 => /usr/lib/x86_64-linux-gnu/libicudata.so.52 (0x00007fba30f2c000) libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007fba30d0f000) librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007fba30b07000) libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007fba307fb000) libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fba304fa000) libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007fba302e4000) libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fba2ff3a000) libboost_chrono.so.1.55.0 => /opt/boost/1.55/lib/libboost_chrono.so.1.55.0 (0x00007fba2fd34000) libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fba2fb2f000) /lib64/ld-linux-x86-64.so.2 (0x00007fba33642000) The program shows the output of cout<<date_time and cout<<as:ftime("%Y-%m...")<<date_time If a mismatch in the year is detected, a "!" is added at the end of the line. When running with en_US locale, the output is as follows: [ 10:49:40 ] [0] $ export LC_ALL=en_US.utf8 [ 10:50:39 ] [0] $ locale LANG= LANGUAGE= LC_CTYPE="en_US.utf8" LC_NUMERIC="en_US.utf8" LC_TIME="en_US.utf8" LC_COLLATE="en_US.utf8" LC_MONETARY="en_US.utf8" LC_MESSAGES="en_US.utf8" LC_PAPER="en_US.utf8" LC_NAME="en_US.utf8" LC_ADDRESS="en_US.utf8" LC_TELEPHONE="en_US.utf8" LC_MEASUREMENT="en_US.utf8" LC_IDENTIFICATION="en_US.utf8" LC_ALL=en_US.utf8 [ 10:50:41 ] [0] $ ./a.out Dec 27, 2000, 12:00:00 AM ++ 2000-12-27 00:00:00 Dec 28, 2000, 12:00:00 AM ++ 2000-12-28 00:00:00 Dec 29, 2000, 12:00:00 AM ++ 2000-12-29 00:00:00 Dec 30, 2000, 12:00:00 AM ++ 2000-12-30 00:00:00 Dec 31, 2000, 12:00:00 AM ++ 2001-12-31 00:00:00 ! Jan 1, 2001, 12:00:00 AM ++ 2001-01-01 00:00:00 Jan 2, 2001, 12:00:00 AM ++ 2001-01-02 00:00:00 Jan 3, 2001, 12:00:00 AM ++ 2001-01-03 00:00:00 Jan 4, 2001, 12:00:00 AM ++ 2001-01-04 00:00:00 Jan 5, 2001, 12:00:00 AM ++ 2001-01-05 00:00:00 Dec 27, 2001, 12:00:00 AM ++ 2001-12-27 00:00:00 Dec 28, 2001, 12:00:00 AM ++ 2001-12-28 00:00:00 Dec 29, 2001, 12:00:00 AM ++ 2001-12-29 00:00:00 Dec 30, 2001, 12:00:00 AM ++ 2002-12-30 00:00:00 ! Dec 31, 2001, 12:00:00 AM ++ 2002-12-31 00:00:00 ! Jan 1, 2002, 12:00:00 AM ++ 2002-01-01 00:00:00 Jan 2, 2002, 12:00:00 AM ++ 2002-01-02 00:00:00 Jan 3, 2002, 12:00:00 AM ++ 2002-01-03 00:00:00 Jan 4, 2002, 12:00:00 AM ++ 2002-01-04 00:00:00 Jan 5, 2002, 12:00:00 AM ++ 2002-01-05 00:00:00 Dec 27, 2002, 12:00:00 AM ++ 2002-12-27 00:00:00 Dec 28, 2002, 12:00:00 AM ++ 2002-12-28 00:00:00 Dec 29, 2002, 12:00:00 AM ++ 2003-12-29 00:00:00 ! Dec 30, 2002, 12:00:00 AM ++ 2003-12-30 00:00:00 ! Dec 31, 2002, 12:00:00 AM ++ 2003-12-31 00:00:00 ! Jan 1, 2003, 12:00:00 AM ++ 2003-01-01 00:00:00 Jan 2, 2003, 12:00:00 AM ++ 2003-01-02 00:00:00 Jan 3, 2003, 12:00:00 AM ++ 2003-01-03 00:00:00 Jan 4, 2003, 12:00:00 AM ++ 2003-01-04 00:00:00 Jan 5, 2003, 12:00:00 AM ++ 2003-01-05 00:00:00 Dec 27, 2003, 12:00:00 AM ++ 2003-12-27 00:00:00 Dec 28, 2003, 12:00:00 AM ++ 2004-12-28 00:00:00 ! Dec 29, 2003, 12:00:00 AM ++ 2004-12-29 00:00:00 ! Dec 30, 2003, 12:00:00 AM ++ 2004-12-30 00:00:00 ! Dec 31, 2003, 12:00:00 AM ++ 2004-12-31 00:00:00 ! Jan 1, 2004, 12:00:00 AM ++ 2004-01-01 00:00:00 Jan 2, 2004, 12:00:00 AM ++ 2004-01-02 00:00:00 Jan 3, 2004, 12:00:00 AM ++ 2004-01-03 00:00:00 Jan 4, 2004, 12:00:00 AM ++ 2004-01-04 00:00:00 Jan 5, 2004, 12:00:00 AM ++ 2004-01-05 00:00:00 Dec 27, 2004, 12:00:00 AM ++ 2005-12-27 00:00:00 ! Dec 28, 2004, 12:00:00 AM ++ 2005-12-28 00:00:00 ! Dec 29, 2004, 12:00:00 AM ++ 2005-12-29 00:00:00 ! Dec 30, 2004, 12:00:00 AM ++ 2005-12-30 00:00:00 ! Dec 31, 2004, 12:00:00 AM ++ 2005-12-31 00:00:00 ! Jan 1, 2005, 12:00:00 AM ++ 2005-01-01 00:00:00 Jan 2, 2005, 12:00:00 AM ++ 2005-01-02 00:00:00 Jan 3, 2005, 12:00:00 AM ++ 2005-01-03 00:00:00 Jan 4, 2005, 12:00:00 AM ++ 2005-01-04 00:00:00 Jan 5, 2005, 12:00:00 AM ++ 2005-01-05 00:00:00 Dec 27, 2005, 12:00:00 AM ++ 2005-12-27 00:00:00 Dec 28, 2005, 12:00:00 AM ++ 2005-12-28 00:00:00 Dec 29, 2005, 12:00:00 AM ++ 2005-12-29 00:00:00 Dec 30, 2005, 12:00:00 AM ++ 2005-12-30 00:00:00 Dec 31, 2005, 12:00:00 AM ++ 2005-12-31 00:00:00 Jan 1, 2006, 12:00:00 AM ++ 2006-01-01 00:00:00 Jan 2, 2006, 12:00:00 AM ++ 2006-01-02 00:00:00 Jan 3, 2006, 12:00:00 AM ++ 2006-01-03 00:00:00 Jan 4, 2006, 12:00:00 AM ++ 2006-01-04 00:00:00 Jan 5, 2006, 12:00:00 AM ++ 2006-01-05 00:00:00 Dec 27, 2006, 12:00:00 AM ++ 2006-12-27 00:00:00 Dec 28, 2006, 12:00:00 AM ++ 2006-12-28 00:00:00 Dec 29, 2006, 12:00:00 AM ++ 2006-12-29 00:00:00 Dec 30, 2006, 12:00:00 AM ++ 2006-12-30 00:00:00 Dec 31, 2006, 12:00:00 AM ++ 2007-12-31 00:00:00 ! Jan 1, 2007, 12:00:00 AM ++ 2007-01-01 00:00:00 Jan 2, 2007, 12:00:00 AM ++ 2007-01-02 00:00:00 Jan 3, 2007, 12:00:00 AM ++ 2007-01-03 00:00:00 Jan 4, 2007, 12:00:00 AM ++ 2007-01-04 00:00:00 Jan 5, 2007, 12:00:00 AM ++ 2007-01-05 00:00:00 Dec 27, 2007, 12:00:00 AM ++ 2007-12-27 00:00:00 Dec 28, 2007, 12:00:00 AM ++ 2007-12-28 00:00:00 Dec 29, 2007, 12:00:00 AM ++ 2007-12-29 00:00:00 Dec 30, 2007, 12:00:00 AM ++ 2008-12-30 00:00:00 ! Dec 31, 2007, 12:00:00 AM ++ 2008-12-31 00:00:00 ! Jan 1, 2008, 12:00:00 AM ++ 2008-01-01 00:00:00 Jan 2, 2008, 12:00:00 AM ++ 2008-01-02 00:00:00 Jan 3, 2008, 12:00:00 AM ++ 2008-01-03 00:00:00 Jan 4, 2008, 12:00:00 AM ++ 2008-01-04 00:00:00 Jan 5, 2008, 12:00:00 AM ++ 2008-01-05 00:00:00 Dec 27, 2008, 12:00:00 AM ++ 2008-12-27 00:00:00 Dec 28, 2008, 12:00:00 AM ++ 2009-12-28 00:00:00 ! Dec 29, 2008, 12:00:00 AM ++ 2009-12-29 00:00:00 ! Dec 30, 2008, 12:00:00 AM ++ 2009-12-30 00:00:00 ! Dec 31, 2008, 12:00:00 AM ++ 2009-12-31 00:00:00 ! Jan 1, 2009, 12:00:00 AM ++ 2009-01-01 00:00:00 Jan 2, 2009, 12:00:00 AM ++ 2009-01-02 00:00:00 Jan 3, 2009, 12:00:00 AM ++ 2009-01-03 00:00:00 Jan 4, 2009, 12:00:00 AM ++ 2009-01-04 00:00:00 Jan 5, 2009, 12:00:00 AM ++ 2009-01-05 00:00:00 Dec 27, 2009, 12:00:00 AM ++ 2010-12-27 00:00:00 ! Dec 28, 2009, 12:00:00 AM ++ 2010-12-28 00:00:00 ! Dec 29, 2009, 12:00:00 AM ++ 2010-12-29 00:00:00 ! Dec 30, 2009, 12:00:00 AM ++ 2010-12-30 00:00:00 ! Dec 31, 2009, 12:00:00 AM ++ 2010-12-31 00:00:00 ! Jan 1, 2010, 12:00:00 AM ++ 2010-01-01 00:00:00 Jan 2, 2010, 12:00:00 AM ++ 2010-01-02 00:00:00 Jan 3, 2010, 12:00:00 AM ++ 2010-01-03 00:00:00 Jan 4, 2010, 12:00:00 AM ++ 2010-01-04 00:00:00 Jan 5, 2010, 12:00:00 AM ++ 2010-01-05 00:00:00 Dec 27, 2010, 12:00:00 AM ++ 2011-12-27 00:00:00 ! Dec 28, 2010, 12:00:00 AM ++ 2011-12-28 00:00:00 ! Dec 29, 2010, 12:00:00 AM ++ 2011-12-29 00:00:00 ! Dec 30, 2010, 12:00:00 AM ++ 2011-12-30 00:00:00 ! Dec 31, 2010, 12:00:00 AM ++ 2011-12-31 00:00:00 ! Jan 1, 2011, 12:00:00 AM ++ 2011-01-01 00:00:00 Jan 2, 2011, 12:00:00 AM ++ 2011-01-02 00:00:00 Jan 3, 2011, 12:00:00 AM ++ 2011-01-03 00:00:00 Jan 4, 2011, 12:00:00 AM ++ 2011-01-04 00:00:00 Jan 5, 2011, 12:00:00 AM ++ 2011-01-05 00:00:00 Dec 27, 2011, 12:00:00 AM ++ 2011-12-27 00:00:00 Dec 28, 2011, 12:00:00 AM ++ 2011-12-28 00:00:00 Dec 29, 2011, 12:00:00 AM ++ 2011-12-29 00:00:00 Dec 30, 2011, 12:00:00 AM ++ 2011-12-30 00:00:00 Dec 31, 2011, 12:00:00 AM ++ 2011-12-31 00:00:00 Jan 1, 2012, 12:00:00 AM ++ 2012-01-01 00:00:00 Jan 2, 2012, 12:00:00 AM ++ 2012-01-02 00:00:00 Jan 3, 2012, 12:00:00 AM ++ 2012-01-03 00:00:00 Jan 4, 2012, 12:00:00 AM ++ 2012-01-04 00:00:00 Jan 5, 2012, 12:00:00 AM ++ 2012-01-05 00:00:00 Dec 27, 2012, 12:00:00 AM ++ 2012-12-27 00:00:00 Dec 28, 2012, 12:00:00 AM ++ 2012-12-28 00:00:00 Dec 29, 2012, 12:00:00 AM ++ 2012-12-29 00:00:00 Dec 30, 2012, 12:00:00 AM ++ 2013-12-30 00:00:00 ! Dec 31, 2012, 12:00:00 AM ++ 2013-12-31 00:00:00 ! Jan 1, 2013, 12:00:00 AM ++ 2013-01-01 00:00:00 Jan 2, 2013, 12:00:00 AM ++ 2013-01-02 00:00:00 Jan 3, 2013, 12:00:00 AM ++ 2013-01-03 00:00:00 Jan 4, 2013, 12:00:00 AM ++ 2013-01-04 00:00:00 Jan 5, 2013, 12:00:00 AM ++ 2013-01-05 00:00:00 Dec 27, 2013, 12:00:00 AM ++ 2013-12-27 00:00:00 Dec 28, 2013, 12:00:00 AM ++ 2013-12-28 00:00:00 Dec 29, 2013, 12:00:00 AM ++ 2014-12-29 00:00:00 ! Dec 30, 2013, 12:00:00 AM ++ 2014-12-30 00:00:00 ! Dec 31, 2013, 12:00:00 AM ++ 2014-12-31 00:00:00 ! Jan 1, 2014, 12:00:00 AM ++ 2014-01-01 00:00:00 Jan 2, 2014, 12:00:00 AM ++ 2014-01-02 00:00:00 Jan 3, 2014, 12:00:00 AM ++ 2014-01-03 00:00:00 Jan 4, 2014, 12:00:00 AM ++ 2014-01-04 00:00:00 Jan 5, 2014, 12:00:00 AM ++ 2014-01-05 00:00:00 When running with de_DE locale, the output is as follows: [ 10:51:42 ] [0] $ export LC_ALL=de_DE.utf8 [ 10:55:04 ] [0] $ locale LANG= LANGUAGE= LC_CTYPE="de_DE.utf8" LC_NUMERIC="de_DE.utf8" LC_TIME="de_DE.utf8" LC_COLLATE="de_DE.utf8" LC_MONETARY="de_DE.utf8" LC_MESSAGES="de_DE.utf8" LC_PAPER="de_DE.utf8" LC_NAME="de_DE.utf8" LC_ADDRESS="de_DE.utf8" LC_TELEPHONE="de_DE.utf8" LC_MEASUREMENT="de_DE.utf8" LC_IDENTIFICATION="de_DE.utf8" LC_ALL=de_DE.utf8 [ 10:55:05 ] [0] $ ./a.out 27.12.2000 00:00:00 ++ 2000-12-27 00:00:00 28.12.2000 00:00:00 ++ 2000-12-28 00:00:00 29.12.2000 00:00:00 ++ 2000-12-29 00:00:00 30.12.2000 00:00:00 ++ 2000-12-30 00:00:00 31.12.2000 00:00:00 ++ 2000-12-31 00:00:00 01.01.2001 00:00:00 ++ 2001-01-01 00:00:00 02.01.2001 00:00:00 ++ 2001-01-02 00:00:00 03.01.2001 00:00:00 ++ 2001-01-03 00:00:00 04.01.2001 00:00:00 ++ 2001-01-04 00:00:00 05.01.2001 00:00:00 ++ 2001-01-05 00:00:00 27.12.2001 00:00:00 ++ 2001-12-27 00:00:00 28.12.2001 00:00:00 ++ 2001-12-28 00:00:00 29.12.2001 00:00:00 ++ 2001-12-29 00:00:00 30.12.2001 00:00:00 ++ 2001-12-30 00:00:00 31.12.2001 00:00:00 ++ 2002-12-31 00:00:00 ! 01.01.2002 00:00:00 ++ 2002-01-01 00:00:00 02.01.2002 00:00:00 ++ 2002-01-02 00:00:00 03.01.2002 00:00:00 ++ 2002-01-03 00:00:00 04.01.2002 00:00:00 ++ 2002-01-04 00:00:00 05.01.2002 00:00:00 ++ 2002-01-05 00:00:00 27.12.2002 00:00:00 ++ 2002-12-27 00:00:00 28.12.2002 00:00:00 ++ 2002-12-28 00:00:00 29.12.2002 00:00:00 ++ 2002-12-29 00:00:00 30.12.2002 00:00:00 ++ 2003-12-30 00:00:00 ! 31.12.2002 00:00:00 ++ 2003-12-31 00:00:00 ! 01.01.2003 00:00:00 ++ 2003-01-01 00:00:00 02.01.2003 00:00:00 ++ 2003-01-02 00:00:00 03.01.2003 00:00:00 ++ 2003-01-03 00:00:00 04.01.2003 00:00:00 ++ 2003-01-04 00:00:00 05.01.2003 00:00:00 ++ 2003-01-05 00:00:00 27.12.2003 00:00:00 ++ 2003-12-27 00:00:00 28.12.2003 00:00:00 ++ 2003-12-28 00:00:00 29.12.2003 00:00:00 ++ 2004-12-29 00:00:00 ! 30.12.2003 00:00:00 ++ 2004-12-30 00:00:00 ! 31.12.2003 00:00:00 ++ 2004-12-31 00:00:00 ! 01.01.2004 00:00:00 ++ 2004-01-01 00:00:00 02.01.2004 00:00:00 ++ 2004-01-02 00:00:00 03.01.2004 00:00:00 ++ 2004-01-03 00:00:00 04.01.2004 00:00:00 ++ 2004-01-04 00:00:00 05.01.2004 00:00:00 ++ 2004-01-05 00:00:00 27.12.2004 00:00:00 ++ 2004-12-27 00:00:00 28.12.2004 00:00:00 ++ 2004-12-28 00:00:00 29.12.2004 00:00:00 ++ 2004-12-29 00:00:00 30.12.2004 00:00:00 ++ 2004-12-30 00:00:00 31.12.2004 00:00:00 ++ 2004-12-31 00:00:00 01.01.2005 00:00:00 ++ 2004-01-01 00:00:00 ! 02.01.2005 00:00:00 ++ 2004-01-02 00:00:00 ! 03.01.2005 00:00:00 ++ 2005-01-03 00:00:00 04.01.2005 00:00:00 ++ 2005-01-04 00:00:00 05.01.2005 00:00:00 ++ 2005-01-05 00:00:00 27.12.2005 00:00:00 ++ 2005-12-27 00:00:00 28.12.2005 00:00:00 ++ 2005-12-28 00:00:00 29.12.2005 00:00:00 ++ 2005-12-29 00:00:00 30.12.2005 00:00:00 ++ 2005-12-30 00:00:00 31.12.2005 00:00:00 ++ 2005-12-31 00:00:00 01.01.2006 00:00:00 ++ 2005-01-01 00:00:00 ! 02.01.2006 00:00:00 ++ 2006-01-02 00:00:00 03.01.2006 00:00:00 ++ 2006-01-03 00:00:00 04.01.2006 00:00:00 ++ 2006-01-04 00:00:00 05.01.2006 00:00:00 ++ 2006-01-05 00:00:00 27.12.2006 00:00:00 ++ 2006-12-27 00:00:00 28.12.2006 00:00:00 ++ 2006-12-28 00:00:00 29.12.2006 00:00:00 ++ 2006-12-29 00:00:00 30.12.2006 00:00:00 ++ 2006-12-30 00:00:00 31.12.2006 00:00:00 ++ 2006-12-31 00:00:00 01.01.2007 00:00:00 ++ 2007-01-01 00:00:00 02.01.2007 00:00:00 ++ 2007-01-02 00:00:00 03.01.2007 00:00:00 ++ 2007-01-03 00:00:00 04.01.2007 00:00:00 ++ 2007-01-04 00:00:00 05.01.2007 00:00:00 ++ 2007-01-05 00:00:00 27.12.2007 00:00:00 ++ 2007-12-27 00:00:00 28.12.2007 00:00:00 ++ 2007-12-28 00:00:00 29.12.2007 00:00:00 ++ 2007-12-29 00:00:00 30.12.2007 00:00:00 ++ 2007-12-30 00:00:00 31.12.2007 00:00:00 ++ 2008-12-31 00:00:00 ! 01.01.2008 00:00:00 ++ 2008-01-01 00:00:00 02.01.2008 00:00:00 ++ 2008-01-02 00:00:00 03.01.2008 00:00:00 ++ 2008-01-03 00:00:00 04.01.2008 00:00:00 ++ 2008-01-04 00:00:00 05.01.2008 00:00:00 ++ 2008-01-05 00:00:00 27.12.2008 00:00:00 ++ 2008-12-27 00:00:00 28.12.2008 00:00:00 ++ 2008-12-28 00:00:00 29.12.2008 00:00:00 ++ 2009-12-29 00:00:00 ! 30.12.2008 00:00:00 ++ 2009-12-30 00:00:00 ! 31.12.2008 00:00:00 ++ 2009-12-31 00:00:00 ! 01.01.2009 00:00:00 ++ 2009-01-01 00:00:00 02.01.2009 00:00:00 ++ 2009-01-02 00:00:00 03.01.2009 00:00:00 ++ 2009-01-03 00:00:00 04.01.2009 00:00:00 ++ 2009-01-04 00:00:00 05.01.2009 00:00:00 ++ 2009-01-05 00:00:00 27.12.2009 00:00:00 ++ 2009-12-27 00:00:00 28.12.2009 00:00:00 ++ 2009-12-28 00:00:00 29.12.2009 00:00:00 ++ 2009-12-29 00:00:00 30.12.2009 00:00:00 ++ 2009-12-30 00:00:00 31.12.2009 00:00:00 ++ 2009-12-31 00:00:00 01.01.2010 00:00:00 ++ 2009-01-01 00:00:00 ! 02.01.2010 00:00:00 ++ 2009-01-02 00:00:00 ! 03.01.2010 00:00:00 ++ 2009-01-03 00:00:00 ! 04.01.2010 00:00:00 ++ 2010-01-04 00:00:00 05.01.2010 00:00:00 ++ 2010-01-05 00:00:00 27.12.2010 00:00:00 ++ 2010-12-27 00:00:00 28.12.2010 00:00:00 ++ 2010-12-28 00:00:00 29.12.2010 00:00:00 ++ 2010-12-29 00:00:00 30.12.2010 00:00:00 ++ 2010-12-30 00:00:00 31.12.2010 00:00:00 ++ 2010-12-31 00:00:00 01.01.2011 00:00:00 ++ 2010-01-01 00:00:00 ! 02.01.2011 00:00:00 ++ 2010-01-02 00:00:00 ! 03.01.2011 00:00:00 ++ 2011-01-03 00:00:00 04.01.2011 00:00:00 ++ 2011-01-04 00:00:00 05.01.2011 00:00:00 ++ 2011-01-05 00:00:00 27.12.2011 00:00:00 ++ 2011-12-27 00:00:00 28.12.2011 00:00:00 ++ 2011-12-28 00:00:00 29.12.2011 00:00:00 ++ 2011-12-29 00:00:00 30.12.2011 00:00:00 ++ 2011-12-30 00:00:00 31.12.2011 00:00:00 ++ 2011-12-31 00:00:00 01.01.2012 00:00:00 ++ 2011-01-01 00:00:00 ! 02.01.2012 00:00:00 ++ 2012-01-02 00:00:00 03.01.2012 00:00:00 ++ 2012-01-03 00:00:00 04.01.2012 00:00:00 ++ 2012-01-04 00:00:00 05.01.2012 00:00:00 ++ 2012-01-05 00:00:00 27.12.2012 00:00:00 ++ 2012-12-27 00:00:00 28.12.2012 00:00:00 ++ 2012-12-28 00:00:00 29.12.2012 00:00:00 ++ 2012-12-29 00:00:00 30.12.2012 00:00:00 ++ 2012-12-30 00:00:00 31.12.2012 00:00:00 ++ 2013-12-31 00:00:00 ! 01.01.2013 00:00:00 ++ 2013-01-01 00:00:00 02.01.2013 00:00:00 ++ 2013-01-02 00:00:00 03.01.2013 00:00:00 ++ 2013-01-03 00:00:00 04.01.2013 00:00:00 ++ 2013-01-04 00:00:00 05.01.2013 00:00:00 ++ 2013-01-05 00:00:00 27.12.2013 00:00:00 ++ 2013-12-27 00:00:00 28.12.2013 00:00:00 ++ 2013-12-28 00:00:00 29.12.2013 00:00:00 ++ 2013-12-29 00:00:00 30.12.2013 00:00:00 ++ 2014-12-30 00:00:00 ! 31.12.2013 00:00:00 ++ 2014-12-31 00:00:00 ! 01.01.2014 00:00:00 ++ 2014-01-01 00:00:00 02.01.2014 00:00:00 ++ 2014-01-02 00:00:00 03.01.2014 00:00:00 ++ 2014-01-03 00:00:00 04.01.2014 00:00:00 ++ 2014-01-04 00:00:00 05.01.2014 00:00:00 ++ 2014-01-05 00:00:00 Sorry for the long post! Did I make any mistake in my program or is this a bug of as::ftime("%Y") formatting? Thank you yery much for your help! Regards, Holger

1 0

[Boost : icpc assignment operator compiler error with boost filter_iterator and filtered_graph
by Aniket Pugaonkar 26 Jun '14

26 Jun '14

Hello, I have the following filter iterator working perfectly with gcc 4.7 and 4.9 as well (C++11 support) But when I compile my code with intel compiler 13.0.1 version I get the following error error: *implicitly generated assignment operator cannot copy: reference member* "my_func::G" ... Details: I am using a filtered_graph over Boost::adjacency_list as my graph type (Graph_t). The vertex_iterator (from graph_traits<Graph_t> .. provides iterator range to iterate over graph vertices. I have to assign each graph vertex an id (using property_maps) and group them together by applying filter_iterator over vertex iterator. example: suppose I want to create 4 subgroups of vertices. So I create a filter predicate which is passed to filter iterator which gives me iterators <fbegin, fend> satisfying the predicate. For FOUR such groups, I get 4 pairs of filter iterators. A vector stores such filter_iterator pairs. std::vector < pair <filter_iterator_t, filter_iterator_t> > my_vector //stores iterator pair. Here is the code: vertex_iterator vbegin, vend; boost::tie(vbegin, vend) = boost::vertices(G); for (int i=0; i<4; ++i) { //for each i, create a filter_pred object my_filter_pred <Graph> filter_pred(G, i) //now create begin and end filter iterators as follows auto fbegin = boost::make_filter_iterator< my_filter_pred<Graph>, vertex_iterator> (filter_pred, vbegin, vend) auto fend = boost::make_filter_iterator< my_filter_pred<Graph>, vertex_iterator> (filter_pred, vend, vend) //fbegin, fend are of type filter iterator //insert the iterator pair into vector my_vector.push_back( std::make_pair (fbegin, fend) ); } The predicate is below : template<typename Graph> struct my_filter_pred { public: my_filter_pred() { } my_filter_pred(Graph& _G, int _value) : G(_G), value(_value) { } template<typename vertex_t> bool operator() (vertex_t vertex) { //get property "p" of vertex in graph G auto p = get (mypropertytype, vertex, G); return (p.val == value); } private: Graph& G; } ERROR : error: implicitly generated assignment operator cannot copy: reference member "my_filter_pred <Graph>::G [with ... ]" I tried to provide my own assignment operator as below: my_filter_pred& operator=(const my_filter_pred& other) { if (this != &other) G = other.G; return *this; } But it gave the same icpc error for actual typedef graph which is below : error: implicitly generated assignment operator cannot copy: " implicit generation of boost::filtered_graph_base<Graph_t> " .... Please help what should I do in this case to work. main motive : is to have a container which stores <iterator, iterator> pair which satisfies a predicate. Filter iterator was the best choice i could have to apply different filter predicate to same vertex_iterator range vbegin, vend; Thanks Aniket Pugaonkar Aniket Pugaonkar

1 0

[Bimap] Iterator invalidation
by Adam Badura 25 Jun '14

25 Jun '14

What are rules for iterator invalidation in Boost.Bimap? I have looked in documentation (version 1.55) but didn't found anything. I'm particularly interested in the bimap<...>::iterator (or ::const_iterator) invalidation. But the question remains valid for any kind of iterators. Adam Badura

2 2

Autobahn for C++: RPC and PubSub
by Tobias Oberstein 24 Jun '14

24 Jun '14

Hi, I'm happy to anounce Autobahn|Cpp - another subproject of Autobahn (http://autobahn.ws) this time for C++ 11 / Boost. Autobahn|Cpp allows remote procedure calls and publish & subscribe messaging for C++ application components and uses boost::future, continuations and Boost/ASIO as underlying network library. Here is how app code looks like: https://github.com/tavendo/AutobahnCpp/blob/master/README.md#show-me-some-c… Using Autobahn|Cpp, you can e.g. call your C++ code from JavaScript running in a browser. And much more. This is an early alpha version, things aren't fully hashed out, but there are a couple of examples included here: https://github.com/tavendo/AutobahnCpp/blob/master/README.md#examples Cheers, /Tobias

2 3

Boost Social Event at CppCon
by Jon Kalb 24 Jun '14

24 Jun '14

Boosters, Because a lot of Boosters are going to be attending CppCon, we¹d like to arrange a social event for Boosters/C++Now regulars. http://cppcon.org/ If you are planning to attend CppCon or even If you are just going to be in or around Bellevue, Washington between September 7th and 12 and you¹d like to join us for dinner, please let us know so we can get a count. Please send mail to: social(a)boost.org Once we settle on a date, etc, we¹ll let everyone who responded know when and where, so please let us know, even if you are a ³maybe.² This year¹s CppCon program includes sessions from a number of Boosters and C++Now regulars with sessions specifically about Boost Libraries. If you are considering attending, please be aware that the Early Bird registration deadline is just days away. http://cppcon.org/registration/ If you are attending, please make your hotel reservations soon. We are likely to sell out of our room block. http://cppcon.org/lodging/ I hope to see you at CppCon. Jon

1 0

Re: [Boost-users] [Boost.Test] BOOST_CHECK_THROW behaviour
by Ghyslain Leclerc 23 Jun '14

23 Jun '14

On 23/06/2014 17:19:01 +1200, Gavin Lambert wrote >>You could try submitting that as a bug report in Trac (if it's not already there), or waiting for Gennadiy Rozental's response. Done. I hope I did it properly. Never reported a bug on Boost before. Quoted our discussion, so that some more info is available if necessary. >>In the meantime, you'd need to write a more intelligent test yourself. I will do it manually. Found someone on Stack Overflow who wanted the same behavior I expected and did it. In case it helps someone, here is the snippet: try { … code that should throw ... BOOST_ERROR( “<function_name> did not throw anything. Expected a <exception_name>” ); } catch( <exception_name> const& ) { //ok, this is the expected case } catch(…) { BOOST_ERROR( “<function_name> has throw an unknown exception, but a <exception_name> was expected.” ); } and the reference: http://stackoverflow.com/questions/21774387/boost-unit-testing-exceptions Thanks again for your help.

1 0

[Boost.Test] BOOST_CHECK_THROW behaviour
by Ghyslain Leclerc 23 Jun '14

23 Jun '14

Hello, Sorry for the long post! I have a simple class, which I am posting a fraction of here for discussion sake: ------------------------------------------------------ class AsciiTableRow { public: void setCol( std::size_t colIdx, std::string const& newContent ); void setCol( std::size_t colIdx, const char* newContent ); private: void checkIdxBound_( std::size_t colIdx, std::string const& msg ); std::vector< std::string > data_; bool maxColWidthIsValid_; } inline void AsciiTableRow::setCol( std::size_t colIdx, std::string const& newVal ) { checkIdxBound_( colIdx, "setCol" ); maxColWidthIsValid_ = false; data_[colIdx] = newVal; } inline void AsciiTableRow::setCol( std::size_t colIdx, const char* newContent ) { setCol( colIdx, std::string( newContent ) ); } inline void AsciiTableRow::checkIdxBound_( std::size_t colIdx, std::string const& msg ) { if( colIdx > data_.size() ) { throw std::out_of_range( "AsciiTableRow::" + msg + " : colIdx out of range" ); } } ------------------------------------------------------ The code above should be sufficient for the discussion and I don’t think any other code is relevant. Should you need to see my constructor and destructor, nothing is virtual so I just copy every value and set some defaults. Nothing fancy, but I will gladly post the code if need be. What I do then is try and devise a test to see if the exception is indeed thrown and if it is the correct one. Here is the code I use: AsciiTableRow testRow; // empty, so any index will throw BOOST_CHECK_THROW( testRow.setCol( 30, 12 ), std::out_of_range ); BOOST_CHECK_THROW( testRow.setCol( 30, 12l ), std::out_of_range ); This works fine. Then, I had the idea to check what the behaviour would be if the wrong exception is thrown. I simply changed the first call like this : BOOST_CHECK_THROW( testRow.setCol( 30, 12 ), std::runtime_error ); BOOST_CHECK_THROW( testRow.setCol( 30, 12l ), std::out_of_range ); I was under the impression (and I might be wrong here, sorry :-( ) that the Boost.Test library would (the numbers are not to mean that order, simply there for enumeration): 1- output a message saying the test has failed, that an exception was indeed thrown, but it was not a runtime_error 2- continue the rest of the test (single test currently) 3- terminate but I actually never get the message of step 1, the execution of the rest of the test seems never occur (the second BOOST_CHECK_THROW) and the program terminate because of my exception and not very gracefully. I guess my questions to the other users here are: - Was my understanding of what BOOST_CHECK_THROW does flawed ? - Is the behaviour normal ? - Is there an obvious problem I am missing with the design of my simple class ? In case it is useful, I am on OSX 10.9. I have compiled boost myself (sources of version 1.55 downloaded from the Boost site). I compile my work with C++11 enabled. I am using GCC 4.7 installed via Macports. Anyhow, any insight will be appreciated. As everyone is busy, thanks in advance to anybody for any time spent on this. Ghyslain

2 1

[asio] Closing async client socket after writing last message
by Nicholas Yue 23 Jun '14

23 Jun '14

Hi, I have adapted the chat tutorial example to send messages to a similar (chat tutorial based) server. It is currently working fine however due to the async_write(), I can't close the socket until after all the pending data has been processed on the server end. I have google and found discussion and mentioned about async_write() completion handler calling socket.close() however, I was not able to find specific detail as to how that is done. I want to avoid closing the connection prematurely as it is asynchronous writing. My current do_write() looks like this void DisplayChatClient::do_write(DisplayChatMessage msg) { DLOG(INFO) << "DisplayChatClient::do_write()"; bool write_in_progress = !write_msgs_.empty(); write_msgs_.push_back(msg); if (!write_in_progress) { boost::asio::async_write(socket_, boost::asio::buffer(write_msgs_.front().data(), write_msgs_.front().length()), boost::bind(&DisplayChatClient::handle_write, this, boost::asio::placeholders::error)); } } void DisplayChatClient::handle_write(const boost::system::error_code& error) { DLOG(INFO) << "DisplayChatClient::handle_write()"; if (!error) { write_msgs_.pop_front(); if (!write_msgs_.empty()) { boost::asio::async_write(socket_, boost::asio::buffer(write_msgs_.front().data(), write_msgs_.front().length()), boost::bind(&DisplayChatClient::handle_write, this, boost::asio::placeholders::error)); } } else { do_close(); } } Cheers -- Nicholas Yue Graphics - Arnold, Alembic, RenderMan, OpenGL, HDF5 Custom Dev - C++ porting, OSX, Linux, Windows http://au.linkedin.com/in/nicholasyue https://vimeo.com/channels/naiadtools

4 7

Boost Filesystem fails with FreeBSD 10, clang, and boost
by Ricky Huang 21 Jun '14

21 Jun '14

Hello all, I am currently migrating to a FreeBSD 10 system which comes default with clang language. I was able to compile Boost just fine. But when I include filesysstem.hpp to it, I get the following error message: > Linking CXX executable boost_clang_test > /usr/bin/ld: : invalid DSO for symbol `_ZN5boost6system15system_categoryEv' definition > /usr/local/lib/libboost_system.so.1.55.0: could not read symbols: Bad value > CC: error: linker command failed with exit code 1 (use -v to see invocation) > *** Error code 1 > > Stop. I am using cmake as my build system, could it be possible that I need to adjust my cmake variables? I am not sure if I've came to correct forum or should this be on FreeBSD, clang, CMake forum(s)? Please let me know if I am at the wrong place… The minimum amount of code to induce the problem are the following 2 files: CMakeLists.txt: cmake_minimum_required(VERSION 2.8) # Find and include Boost libraries find_package(Boost 1.55 COMPONENTS filesystem REQUIRED) include_directories(${Boost_INCLUDE_DIR}) set(LIBS ${LIBS} ${Boost_LIBRARIES}) set(BOOST_CLANG_TEST_SOURCES ${SOURCES} main.cpp) add_executable(boost_clang_test ${BOOST_CLANG_TEST_SOURCES}) target_link_libraries(boost_clang_test ${LIBS}) main.cpp: #include <stdio.h> #include <iostream> #include <sstream> #include <string> #include <boost/filesystem.hpp> using namespace std; using namespace boost::filesystem; const char *progname; int main(int argc, char **argv){ return 0; } Thanks in advance.

3 4

[graph] kamada_kawai_spring_layout warnings
by Michael Olea 21 Jun '14

21 Jun '14

Hi. I'm getting compiler warnings for subscripts out of range from kamada_kawai_spring_layout.hpp. I'm using boost_55_0, compiled with clang: Apple LLVM version 5.1 (clang-503.0.40) (based on LLVM 3.4svn) Target: x86_64-apple-darwin13.2.0 Thread model: posix ../../../../../include/boost/graph/kamada_kawai_spring_layout.hpp:110:49: warning: array index 2 is past the end of the array (which contains 2 elements) [-Warray-bounds] double denom = mat[0][0] * (mat[1][1] * mat[2][2] - mat[2][1] * mat[1][2]) The offending code is: template <> struct linear_solver<3> { template <typename Vec> static Vec solve(double mat[2][2], Vec rhs) { double denom = mat[0][0] * (mat[1][1] * mat[2][2] - mat[2][1] * mat[1][2]) - mat[1][0] * (mat[0][1] * mat[2][2] - mat[2][1] * mat[0][2]) + mat[2][0] * (mat[0][1] * mat[1][2] - mat[1][1] * mat[0][2]); double x_num = rhs[0] * (mat[1][1] * mat[2][2] - mat[2][1] * mat[1][2]) - rhs[1] * (mat[0][1] * mat[2][2] - mat[2][1] * mat[0][2]) + rhs[2] * (mat[0][1] * mat[1][2] - mat[1][1] * mat[0][2]); double y_num = mat[0][0] * (rhs[1] * mat[2][2] - rhs[2] * mat[1][2]) - mat[1][0] * (rhs[0] * mat[2][2] - rhs[2] * mat[0][2]) + mat[2][0] * (rhs[0] * mat[1][2] - rhs[1] * mat[0][2]); double z_num = mat[0][0] * (mat[1][1] * rhs[2] - mat[2][1] * rhs[1] ) - mat[1][0] * (mat[0][1] * rhs[2] - mat[2][1] * rhs[0] ) + mat[2][0] * (mat[0][1] * rhs[1] - mat[1][1] * rhs[0] ); Vec result; result[0] = x_num / denom; result[1] = y_num / denom; result[2] = z_num / denom; return result; } }; Looks like it should be: static Vec solve(double mat[3][3], Vec rhs) ... No?

1 0

stack unwinding with boost::fcontext
by David Frank 20 Jun '14

20 Jun '14

Context - 1.53.0 beta1 Context - 1.53.0 beta1 Context Struct fcontext_t and related functions Each instance of fcontext_t represents a context (CPU registers and stack space). View on www.boost.org Preview by Yahoo I'm wondering if there is any example showing how to do stack unwinding as described at the bottom of the above link as quoted below: " Stack unwinding Sometimes it is necessary to unwind the stack of an unfinished context to destroy local stack variables so they can release allocated resources (RAII pattern). The user is responsible for this task. " Thanks, Frank

2 1

[coroutine] await_emu example
by bbxiong 20 Jun '14

20 Jun '14

Hi, coroutine listers! The example is very awesome. but after reading though the source, i have a question: Is any limitation makes a push_coroutine must be caller and pull_coroutine must be the coro? This way, we have to yield out at the first line of coroutine function by calling caller(), just like the example showed: typedef coroutines::pull_coroutine<void> coro_pull; typedef coroutines::pull_coroutine<void> coro_push; auto asynchronous(F f) -> future<decltype(f())> { typedef promise<decltype(f())> CoroPromise; CoroPromise coro_promise; auto coro_future = coro_promise.get_future(); CurrentCoro current_coro = { make_shared<coro_pull>(std::bind([f](CoroPromise &coro_promise, coro_push &caller) { caller(); coro_stack.top().caller = &caller; coro_promise.set_value(f()); }, std::move(coro_promise), placeholders::_1); }; coro_stack.push(std::move(current_coro)); (*coro_stack.top().coro)(); coro_stack.pop(); return coro_future; } There is an extra call to caller() in coroutine function to jump out to prepare coro stack. Why not swap coro_pull and coro_push like this: auto asynchronous(F f) -> future<decltype(f())> { typedef promise<decltype(f())> CoroPromise; CoroPromise coro_promise; auto coro_future = coro_promise.get_future(); CurrentCoro current_coro = { make_shared<coro_push>(std::bind([f](CoroPromise &coro_promise, coro_pull &caller) { coro_stack.top().caller = &caller; coro_promise.set_value(f()); }, std::move(coro_promise), placeholders::_1); }; coro_stack.push(std::move(current_coro)); (*coro_stack.top().coro)(); coro_stack.pop(); return coro_future; } This still works on my machine, and has no extra "call to caller()", push_coroutine is not invoked until we explicitly run it (while pull_coroutine is invoked in constructor). So, my question is, s there any bad effects by using coroutines in this way? Thanks in advance!

2 1

How to use vertex mapping parameter in copy_graph
by Christoph Czurda 19 Jun '14

19 Jun '14

Hello! I want to create a straight line drawing of a planar graph that is not maximal planar. So I want to follow the instructions in http://www.boost.org/doc/libs/1_55_0/libs/graph/doc/straight_line_drawing.h… : "If you want to draw a graph g, you can create a copy g' of g, store a mapping m of vertices in g' to vertices in g, triangulate g', and then send g' in as the input to chrobak_payne_straight_line_drawing. The drawing returned can then be applied to g using m to translate vertices from one graph to another." But I'm stuck at the point where I need to make a copy of the graph and store the vertex-to-vertex mapping between the two graphs. I'm not good enough at C++ to understand from the documentation at http://www.boost.org/doc/libs/1_55_0/libs/graph/doc/copy_graph.html how to provide or access the last parameter orig_to_copy(Orig2CopyMap c) If someone could fill in the missing code in this function, I would be most thankful! void doSomething(MyGraph_t& g){ MyGraph_t g_copy; copy_graph(g, g_copy, [...???...]); // here I would like to access the Orig2CopyMap which stores the mapping }

1 0

Prominent Booster makes a big splash
by Robert Ramey 19 Jun '14

19 Jun '14

Notice that our own Matthias Troyer - important boost contributor made a big splash. http://www.theverge.com/2014/6/19/5824336/google-s-quantum-computer-just-fl… Robert Ramey -- View this message in context: http://boost.2283326.n4.nabble.com/Prominent-Booster-makes-a-big-splash-tp4… Sent from the Boost - Users mailing list archive at Nabble.com.

1 0

[archive] binary archive to memory stream
by Michael Powell 19 Jun '14

19 Jun '14

Hello, I am wrapping my head around archive, specifically binary archive. I'd like to serialize a vector of objects in such a way, I need to capture intermediate vector buffers (literally, to vector of uint8_t) so that I can determine their sizes. After which point the parent object(s) can serialize to file using more conventional, built-in file streams and such. It seems that binary_oarchive is helpful, but still requires there be an ostream or streambuf in the mix. Which, as an adapter layer, while helpful, it still leaves the question of extending streambuf to work with ostream to vector<uint8_t> open. I've read some docs on vectors and streambuf, but they all seem to be geared towards a known-size vector, istream and such. I am interested in a vector that can be streamed to, will grow in size, etc. Some clues seem to hint at underflow, overflow type issues? Any helpful pointers how to go about doing this? Thanks... Best regards, Michael Powell

4 5

[Python]compiling python library
by Miklós Tóth 19 Jun '14

19 Jun '14

Hi All, I want to embed python in my c++ code using boost.python library. As far as I understand I need python headers and libs. So my python27.lib is "incompatible". I want to compile it from code but I failed with mingw32. Could you give me some advice, or links to achieve my goal? I'm using gcc4.6.3 and qt 4.8.2 and boost 1.49 on windows 7. Thanks, Miklós

2 9

Possible problem with property tree and ini files
by Tim Burgess 19 Jun '14

19 Jun '14

Hi, I make the following call in my application, based on Boost 1.55.0: property_tree::ini_parser::read_ini(IniFile.GetFullPath().ToStdString(), IniTree); This works fine for .ini files up to 64kb, but throws an exception for larger files. Is this a known limitation and, if so, can anybody suggest an alternative that could cope with larger files, please? Best wishes. Tim Burgess

1 0

Splitting string at whitespace
by Florian Lindner 17 Jun '14

17 Jun '14

Hello, for some time now I've been trying to split a given string at whitespaces: "A B C" -> "A", "B", "C". I want to use boost/algorithm/string #include "boost/algorithm/string/split.hpp" #include "boost/algorithm/string/compare.hpp" std::vector<std::string> tokenize(const std::string& text ) { std::vector<std::string> tokens; boost::algorithm::split(tokens, text, boost::algorithm::is_equal(" ")); return tokens; } but compilation on gcc 4.9.0 / boost 1.55.0 just gives: test.cpp: In function 'std::vector<std::basic_string<char> > tokenize(const string&)': test.cpp:40:71: error: no matching function for call to 'boost::algorithm::is_equal::is_equal(const char [2])' boost::algorithm::split(tokens, text, boost::algorithm::is_equal(" ")); ^ test.cpp:40:71: note: candidates are: In file included from /usr/include/boost/algorithm/string/finder.hpp:24:0, from /usr/include/boost/algorithm/string/split.hpp:17, from test.cpp:7: /usr/include/boost/algorithm/string/compare.hpp:34:16: note: boost::algorithm::is_equal::is_equal() struct is_equal ^ /usr/include/boost/algorithm/string/compare.hpp:34:16: note: candidate expects 0 arguments, 1 provided /usr/include/boost/algorithm/string/compare.hpp:34:16: note: boost::algorithm::is_equal::is_equal(const boost::algorithm::is_equal&) /usr/include/boost/algorithm/string/compare.hpp:34:16: note: no known conversion for argument 1 from 'const char [2]' to 'const boost::algorithm::is_equal&' What is wrong there? Thanks, Florian

2 1

Boost Voronoi: Automate creation of graph for indoor navigation
by Stadin, Benjamin 16 Jun '14

16 Jun '14

Hi all, I’m provided with geometry data for buildings. The data contains info about the „feature“ type of a geometry (floor, room, stairway, elevator). Now I need to automate the creation of an indoor routing graph (room-to-room navigation) to minimize manual works later on. This is not for a robot scenario – the line parts will be shown on a map application. Therefore it should also look good (routing edges should be centered etc). This is new land for me and I’ll will be grateful for advise how to achieve this. My initial thought is that Voronoi may be helpful. But this alone will probably not be sufficient. Any pointers and examples welcome. Thanks Ben

2 1

[numeric conversation] behavior on std::numeric_limits<double>::max() + eps with numeric_cast
by Olaf Peter 16 Jun '14

16 Jun '14

Hello, at this time I play with numeric_cast and struggle with this: first: double z = std::numeric_limits<double>::max(); z += 2*std::numeric_limits<double>::epsilon(); // doesn't matter if 1*eps std::cout << z << std::endl; std::cout << boost::numeric_cast<double>(z) << '\n'; I would expect that an exception is thrown which isn't, the output is 1.79769e+308 1.79769e+308 and as second: If I write my onw UDT as shown in the tutorial like: namespace my { enum range_check_result { cNonFinite = 0, cInRange = 1, cNegOverflow = 2, cPosOverflow = 3 } ; //! Define a custom range checker template<typename Traits, typename OverFlowHandler> struct range_checker { typedef typename Traits::argument_type argument_type; typedef typename Traits::source_type S; typedef typename Traits::target_type T; //! Check range of integral types. static range_check_result out_of_range(argument_type value) { if(!std::isfinite(value.to_builtin())) // Neither infinity nor NaN. return cNonFinite; else if(value > boost::numeric::bounds<T>::highest()) return cPosOverflow; else if(value < boost::numeric::bounds<T>::lowest()) return cNegOverflow; else return cInRange; } static void validate_range(argument_type value) { BOOST_STATIC_ASSERT(std::numeric_limits<T>::is_bounded); OverFlowHandler()(out_of_range(value)); } }; .... struct bad_numeric_cast : virtual boost::exception, virtual std::bad_cast { ... }; struct rounding_error : virtual boost::exception, std::domain_error { rounding_error() : std::domain_error("NaN or Infinity") {} // XXX Better solution? virtual const char * what() const throw() { return "bad numeric conversion: can not be represented in the target integer type"; } }; struct negative_overflow : virtual bad_numeric_cast { .... }; struct positive_overflow : virtual bad_numeric_cast { .... }; struct overflow_handler { void operator()(range_check_result result) { if(result == cNonFinite) BOOST_THROW_EXCEPTION(rounding_error()); else if(result == cNegOverflow) BOOST_THROW_EXCEPTION(negative_overflow()); else if(result == cPosOverflow) BOOST_THROW_EXCEPTION(positive_overflow()); } }; it doesn't change the result - is this the right way? Thanks, Olaf

4 15

[asio]remote_endpoint throws exception
by higashiyama＠ncad.co.jp 16 Jun '14

16 Jun '14

Hi, I wrote TCP client program using boost::asio. OS: Debian GNU/Linux (x86_64) Boost: 1.49 I use asio::ip::tcp::socket::async_conect function and I called ip::tcp::socket::remote_endpoint at async_connect callback. Like this: // async_resolve handler void my_class::handle_resolve(const boost::system::error_code& error, boost::asio::ip::tcp::resolver::iterator endpoint_iterator) { if (!error) { socket_.async_connect(endpoint, strand_.wrap(...)); } } void my_class::handle_connect(const boost::system::error_code& error, boost::asio::ip::tcp::resolver::iterator endpoint_iterator) { if (!error) { // socket_ is my_class member. socket_.remote_endpoint(); // throw exception ! } ... } ip::tcp::socket::remote_endpoint sometime throws boost::system::system_error exception (error message is "remote_endpoint: Transport endpoint is not connected"). But async_connect is successfully completed. Why does remote_endpoint function throw exception? Thank you,

3 3

[boost::filesystem] Improvement/Suggestion for copy()
by Kyle Ketterer 15 Jun '14

15 Jun '14

Hello all, I was curious about the possible implementation of a progress call back for the copy() ( and related functions) in ::filesystem. With WinAPI you can use CopyFileEx with the possibility of a progress call back. It would be nice to have this ability "out of the box" in boost's namespace. This would be especially be useful for transferring larger files. Thoughts? Thanks

1 0

[geometry] how to using UDT
by Olaf Peter 15 Jun '14

15 Jun '14

Hello, I try to catch some failures using an own user defined type (UDT), but it doesn't compile e.g. it's hardcoded to use std::sqrt: boost_1_55_0/boost/geometry/strategies/cartesian/distance_pythagoras.hpp:165:13: error: no matching function for call to 'sqrt(core::my_type<double>)' further, is there a way to adapt templated points? BOOST_GEOMETRY_REGISTER_POINT_2D(point_type, point_type::coordiante_type, bg::cs::cartesian, x, y) got errrors. Thanks, Olaf

2 2

BGL performance: is pool_allocator possible and does it help iteration performance?
by Jeremy Murphy 15 Jun '14

15 Jun '14

Hi, I'm implementing a graph algorithm that requires a lot of repeated iteration over a graph as it builds it. So I wonder about cache misses. Is it possible to use a pooled allocator with the vector/list that gets used in the VertexList and EdgeList properties of adjacency_list? If there are other techniques for improving search/iteration performance (at the cost of insertion), I'd also be interested. Thanks! Jeremy

1 0

Boost Library Incubator recommended by steering committee
by Beman Dawes 14 Jun '14

14 Jun '14

The Boost Library Incubator (www.blincubator.com) is a web site conceived, designed, and implemented to alleviate the log-jam of libraries waiting to be reviewed by Boost. It helps new library submitters through the process, encourages development of an initial user base, and accumulates feedback in the form of comments, test results and Boost style reviews. The Boost Steering Committee has voted to recommend using the Boost Library Incubator as a prelude to getting a library reviewed by Boost. The Steering Committee recommends libraries currently in the Boost review queue be added to the Incubator by their developers. The relationship between Boost and the Incubator is purely informal, but there as several things Boosters can do to help make the Incubator a success. Authors can submit their libraries and respond to feedback. Users can experiment with submitted libraries and provide feedback on their experience. WordPress/php developers can contribute enhancements to the Boost Library Incubator implementation. The steering committee extends its thanks to Robert Ramey for launching the Boost Library Incubator! --The Boost Steering Committee

3 2

[utility] prior(it, n) for n being an unsigned type
by Adam Romanek 13 Jun '14

13 Jun '14

Hi! I've just finished investigating an issue in my code which led it to an assert/abort in certain cases. It turned out it was caused by the use of boost::prior(it, n) where n was unsigned int with some non-zero value. I found a question [1] on the mailing list back in 2004 which describes this issue. Additionally a solution to this problem was also posted in one of the replies [2]. My question is - why hasn't it made into the repository yet? The current behavior of boost::prior(it, n) when n is unsigned type is far from the one expected by its potential users so I think it should either be properly documented (warned) or fixed immediately. Am I not seeing something? WBR, Adam Romanek [1] http://lists.boost.org/Archives/boost/2004/02/61556.php [2] http://lists.boost.org/Archives/boost/2004/02/61578.php

1 0

std::limits compile errors with boost
by David Frank 13 Jun '14

13 Jun '14

Anyone has seen this?: In file included from ../include/boost/lockfree/detail/freelist.hpp:12, from ../include/boost/lockfree/queue.hpp:24, from test.cpp:2: /usr/local/powerpc-linux-gnu/include/c++/4.3.2/limits:287:22: error: macro "min" requires 2 arguments, but only 1 given Thanks

4 3

<boost::wave> Memory issue when using wave to run a file parser service
by Yong Huang 12 Jun '14

12 Jun '14

Hi all, I run into a memory issue when uses boost wave library. My application runs as a *service *that parses c files. In each individual run, it calls in the wave library through a sub-function call to process one file. I noticed that some memory is not released from wave after each run. The consequence is that the memory usage of the application keeps increasing till the system breaks down. I could reproduce the problem with a simple modification of the quick_start sample code shipped with the boost wave library. (attached below). My system is win64 and I see the problem with both 1.49 and 1.55. (built with b2 toolset=msvc-11.0 address-model=64 --build-type=complete) Something I found during the investigation: * The problem is gone if I build the application with link<static>. (Unfortunately, this is not an option for me) * From the memory usage pattern, it seems that there is a memory pool in place that should have been released after each turn. When repeatedly passing a 4MB file, the memory usage (taken from task maneger) is: 99,700K, 198,404K, 395,404K, 395408K, and 789,396K. When running with static link, the memory usage after each run is: 1800K, 2480K, 2480K, .... The maximum usage is 8300K. Is there any workaround with the problem? Thanks, Yong ------------------------------------- begin of the code --------------------------------------------------- #define BOOST_WAVE_SERIALIZATION 0 // enable serialization #define BOOST_WAVE_BINARY_SERIALIZATION 0 // use binary archives #define BOOST_WAVE_XML_SERIALIZATION 1 // use XML archives /////////////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////////////// // Include Wave itself #include <boost/wave.hpp> /////////////////////////////////////////////////////////////////////////////// // Include the lexer stuff #include <boost/wave/cpplexer/cpp_lex_token.hpp> // token class #include <boost/wave/cpplexer/cpp_lex_iterator.hpp> // lexer class // sub-function that calls into wave int do_it(std::string filename) { boost::wave::util::file_position_type current_position; std::ifstream instream(filename); std::string instring; instream.unsetf(std::ios::skipws); instring = std::string(std::istreambuf_iterator<char>(instream.rdbuf()), std::istreambuf_iterator<char>()); typedef boost::wave::cpplexer::lex_token<> token_type; typedef boost::wave::cpplexer::lex_iterator<token_type> lex_iterator_type; typedef boost::wave::context<std::string::iterator, lex_iterator_type> context_type; typedef boost::wave::cpplexer::lex_token<> TokenType; typedef boost::wave::cpplexer::lex_iterator<TokenType> LexIterator; LexIterator aIter(instring.begin(), instring.end(), TokenType::position_type( filename.c_str()), boost::wave::language_support( boost::wave::support_cpp | boost::wave::support_option_long_long ) ); LexIterator endIter; for (; aIter != endIter; ) { (*aIter).get_value(); ++aIter; } return 0; } int main(int argc, char *argv[]) { int aNum = 1; for (;;) { do_it("c:\\memleak.txt"); std::cout << "Process the file again (0/1)? \n"; scanf("%d", &aNum); if (aNum == 0) { printf("\nYou entered zero so we stop!\n"); return 0; } } return 0; }

2 1

[python] TypeError when left side is noncopyable
by Igor R 12 Jun '14

12 Jun '14

I'm trying to expose an operator: struct my_class : boost::noncopyable {}; my_class &operator <<(my_class &e, int i); // in the module definition: class_<my_class, boost::noncopyable>("my_class") .def(self << int()) ; However, an attempt to invoke this operator in python causes the following error: TypeError: No to_python (by-value) converter found for C++ type: my_class I guess this is related to the fact my_class is noncopyable, isn't it? Is there a workaround for this issue? Thanks.

1 0

Meeting C++ Schedule released
by Jens Weller 12 Jun '14

12 Jun '14

Hello C++ & Boost Community, since last week the schedule for Meeting C++ is released: http://meetingcpp.com/index.php/schedule14.html Like last year Meeting C++ will feature 21 Talks in 3 Tracks, the conference will be opened by Scott Meyers, the closing Keynote will be given by Hartmut Kaiser. This years Theme Track is "Scientific Programming with C++". Also, if your are a student, you have the chance to participate in our student program which will give 50 Students access to the conference: http://meetingcpp.com/index.php/newsreader/items/meeting-cpp-2014-the-stude… kind regards, Jens Weller

1 0

pure virtuals on multiple hierarchy levels
by Igor R 12 Jun '14

12 Jun '14

Hello, What's the right way to wrap the following, when exposing this hierarchy to Python: sturct base { virtual void func1() = 0; }; struct intermediate : base { virtual void func2() = 0; }; struct derived : intermediate { void func1(); void func2(); }; Thanks.

1 0

[BGL]
by Pablo Madoery 11 Jun '14

11 Jun '14

Hello, I Have 2 graphs: graph1 and graph2, and two sets of edge descriptors. One set is associated to edges of graph1 and another set associated to edges of graph2. I don't understand why is it possible to access information about edges of graph2 by using graph1 and the edge descriptors of graph2. I realized of that because of an own mistake when using graphs. What I would like to know is why is that possible to do and if it should be an exception that can handle this situation. I send the code I was using to test this: #include <iostream> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/graphviz.hpp> #include <fstream> #include "GraphInfo.h" using namespace std; using namespace boost; typedef adjacency_list<setS, vecS, bidirectionalS, VertexInfo, EdgeInfo> Graph; void printGraph(Graph graph, string file) { ofstream ofs(file.c_str()); dynamic_properties dp; dp.property("node_id", get(vertex_index, graph)); dp.property("label", get(&EdgeInfo::weight, graph)); write_graphviz_dp(ofs, graph, dp); } int main() { Graph graph1; Graph::vertex_descriptor a1 = add_vertex(graph1); Graph::vertex_descriptor b1 = add_vertex(graph1); Graph::vertex_descriptor c1 = add_vertex(graph1); Graph::edge_descriptor e1 = (add_edge(a1, b1, graph1)).first; Graph::edge_descriptor e2 = (add_edge(b1, a1, graph1)).first; graph1[a1].id = 10; graph1[b1].id = 20; graph1[c1].id = 30; graph1[e1].weight = 1; graph1[e2].weight = 2; Graph graph2; Graph::vertex_descriptor a2 = add_vertex(graph2); Graph::vertex_descriptor b2 = add_vertex(graph2); Graph::vertex_descriptor c2 = add_vertex(graph2); Graph::vertex_descriptor d2 = add_vertex(graph2); Graph::edge_descriptor e4 = (add_edge(c2, b2, graph2)).first; Graph::edge_descriptor e5 = (add_edge(b2, c2, graph2)).first; Graph::edge_descriptor e6 = (add_edge(d2, a2, graph2)).first; Graph::edge_descriptor e7 = (add_edge(a2, d2, graph2)).first; graph2[a2].id = 10; graph2[b2].id = 20; graph2[c2].id = 30; graph2[e4].weight = 13; graph2[e5].weight = 14; graph2[e6].weight = 15; graph2[e7].weight = 16; // WHY IS THIS POSSIBLE TO DO // IT IS ASKING FOR AN EDGE OF GRAPH2 BUT USING GRAPH1 ??? double weight = graph1[e7].weight; cout<<"weight: "<<weight<<endl; printGraph(graph1, "graph1.dot"); printGraph(graph2, "graph2.dot"); cout << "end" << endl; return 0; } Thank you very much

2 1

Fwd: Lexical cast between narrow and wide strings
by Andrew Marlow 11 Jun '14

11 Jun '14

I hope this is the right place to post my question. I expected to be able to convert between narrow and wide strings using boost lexical cast but it fails to compile. I suppose that conversion is not supplied or supported. It would be really useful to me if it was. I am developing on win32 for wince and on wince there seeem to be many places where wide strings are required, especially when using the win32 API. Is there any chance this could be added to boost? I checked using boost 1.55.0 -- Regards, Andrew Marlow http://www.andrewpetermarlow.co.uk

5 6

Is boost asio appropriate for this use case ?
by Aaron Boxer 10 Jun '14

10 Jun '14

I am decoding an image file: the file has tagged header info mixed with 4K pixel code blocks. Platform is primarily windows, but could be osx or linux. Once I read in a code block, I can launch (asynchronously) my decode routine on this block, while continuing to read the file for header info and code blocks. Currently, I do synchronous reads using fread(...). Is is worthwhile to switch to boost asio to asynchronously read in the code blocks? The read callback could trigger my decode routine. But I wouldn't have to wait for the read before I carry on to the next code block. If so, can anyone point me to a reference/tutorial covering boost::asio asynch reads from disk?

3 3

[boost] [pimpl] Boost.Pimpl review canceled
by Glen Fernandes 09 Jun '14

09 Jun '14

Hi everyone, Vladimir has elected to withdraw Boost.Pimpl submission and cancel the formal review. On behalf of Vladimir, thank you for the feedback provided in response to the pre-view announcement mail: it was especially useful to him. Best, Glen

1 0

memory mapped file thread safety
by Aaron Boxer 09 Jun '14

09 Jun '14

Simple question: If I call get_address() on a region, can I pass this pointer to another thread and have this thread access the memory ? Thanks!

2 2

Boost Build
by skk 09 Jun '14

09 Jun '14

I am building Boost for MSVS10.0. I have generated the bjam.exe file and run it with the command line: bjam toolset=msvc10.0 variant=debug,release threading=multi link=static Looking at the libraries built, there are no sgd libs and the linker wants: libboost_regex-vc100-mt-sgd-1_55.lib Don't know how to get the sgd libs. Thanks -- View this message in context: http://boost.2283326.n4.nabble.com/Boost-Build-tp4663758.html Sent from the Boost - Users mailing list archive at Nabble.com.

3 2

[Filesystem] remove and recursive_directory_iterator
by gast128 09 Jun '14

09 Jun '14

I couldn't find a description of the iterator stability of recursive_directory_iterator but it gives problems when you remove the directory which is being iterated even when that directory is empty. For example if you want to remove all empty directories, the following code will throw an exception in ++it after the 'remove' call: fs::path pthDirectory = ...; fs::recursive_directory_iterator itEnd; for (fs::recursive_directory_iterator it(pthDirectory); it != itEnd; ++it) { boost::system::error_code ec; const fs::path& rPath = it->path(); if (fs::is_directory(rPath, ec)) { if (fs::is_empty(rPath, ec)) { fs::remove(rPath, ec); } } } It seems solvable with the way one erases a map (i.e. using while (it != itEnd) and using the equivalent of map.erase(it++)). Maybe add a note to the documentation or did I overlook something?

1 0

Writing a dynamic string into a shared memory using Boost Library
by Hany Assasa 09 Jun '14

09 Jun '14

I want to share a dynamic array of characters between two processes using Boost Shared Memory. I use the following two pieces of code to do that: *Producer Process:* char *data;unsigned int share_length;unsigned int offset; std::string data_to_share(data + offset, data + offset + share_length); boost::interprocess::managed_shared_memory managed_shm(boost::interprocess::create_only, "SomeName", 1024*1024);typedef boost::interprocess::allocator<char, boost::interprocess::managed_shared_memory::segment_manager> CharAllocator;typedef boost::interprocess::basic_string<char, std::char_traits<char>, CharAllocator> my_string; managed_shm.construct<my_string>("DataToShare")(data_to_share.c_str(), managed_shm.get_segment_manager()); *Consumer Process:* boost::interprocess::managed_shared_memory managed_shm(boost::interprocess::open_read_only, "SomeName");typedef boost::interprocess::allocator<char, boost::interprocess::managed_shared_memory::segment_manager> CharAllocator;typedef boost::interprocess::basic_string<char, std::char_traits<char>, CharAllocator> my_string; std::pair<my_string *, size_t > data = managed_shm.find<my_string>("DataToShare"); cout << "Data Size=" << data.first->length() << endl; The problem is when I try to print the length of the DataToShare in the Consumer Process it is wrong, so what is the problem in my code, is it in the Producer Part since I am doing data_to_share.c_str()which is a std::string type instead of of my_string type? *Possible Answer:* I believe the answer to my question is, converting std::string into my_string type. so can anyone tell me how to do that?

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[mpl] Cannot open include file
by Christian Henning 09 Jun '14

09 Jun '14

I have the following error when using Visual Studio 2013 on the boost master branch: 1>c:\boost\boost\mpl\vector\aux_\include_preprocessed.hpp(49): fatal error C1083: Cannot open include file: 'boost/mpl/vector/aux_/preprocessed/plain/vector10.hpp': No such file or directory I have run "b2 headers". Here is the code I'm trying to compile: // cpp_test.cpp : Defines the entry point for the console application. // #include "stdafx.h" #include <boost/mpl/vector_c.hpp> int _tmain(int argc, _TCHAR* argv[]) { return 0; } Manually I can find vector10.hpp in C:\boost\boost\mpl\vector but I don't have the folder c:/boost/mpl/vector/aux_/preprocessed/plain/ Any ideas? Thanks, Christian Regards, Christian

2 1

Using a vertex type
by Mads Jensen 09 Jun '14

09 Jun '14

Hi, I'm planning on writing an implementation of the Gomory Hu cut tree algorithm (for learning purposes, and as a side bonus, have some code in open source), but have some initial difficulties. I posted some code at: http://codepad.org/yTt3xNsK I had tried something like: template<class OrdinaryVertex> struct gomory_hu_vertex { std::vector<OrdinaryVertex> vertices; }; and the graph definition: typedef adjacency_list<listS, vecS, undirectedS, GHVertex> GHGraph; but with the insert operation, I get a compiler error. When I get it working, I want to submit it to the boost library. Are there restrictions on what type of features you can use, e.g., anything from C++11 is ruled out? Thank you, Mads

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[serialization] serialize object tree and values
by Daniel Krikun 07 Jun '14

07 Jun '14

Hello, I have an application which creates some objects connected between them using boost::shared_ptr and then executes a main loop. The object graph structure is almost constant over time but primitive member fields of the objects change over time. I would like to serialize the whole object graph *each cycle* saving both the object graph structure and primitive member fields. Currently I don't know how to achieve this: when I try to serialize via pointer only first value is saved. Also, I'm not sure if I should turn object tracking off, because indeed it should be a single instance of each, it just should be modified over time. Thanks!

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Re: [Boost-users] Boost-users Digest, Vol 3819, Issue 2
by David Frank 06 Jun '14

06 Jun '14

Thanks Nat. I'm wondering if there is a powerpc built binary including context to download? On Thursday, June 5, 2014 8:25 AM, "boost-users-request(a)lists.boost.org" <boost-users-request(a)lists.boost.org> wrote: Send Boost-users mailing list submissions to boost-users(a)lists.boost.org To subscribe or unsubscribe via the World Wide Web, visit http://lists.boost.org/mailman/listinfo.cgi/boost-users or, via email, send a message with subject or body 'help' to boost-users-request(a)lists.boost.org You can reach the person managing the list at boost-users-owner(a)lists.boost.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Boost-users digest..." Today's Topics: 1. Re: [Python]compiling python library (Mikl?s T?th) 2. Re: is boost context supported on powerpc?- (Nat Goodspeed) 3. Re: Fwd: Lexical cast between narrow and wide strings (Nat Goodspeed) 4. Re: [Python]compiling python library (Erik H) ---------------------------------------------------------------------- Message: 1 Date: Thu, 5 Jun 2014 13:18:44 +0200 From: Mikl?s T?th <spiralfuzet(a)gmail.com> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] [Python]compiling python library Message-ID: <CAHsDByksou9LpheA6g-Napu6GPKjbAdtYFZeC2psuRhRCUDivQ(a)mail.gmail.com> Content-Type: text/plain; charset="utf-8" Hi Erik, Unfortunatly Visual Studio is not an option for me. I didn't find this page but as I understand it helps to install python libs (extensions) with mingw. What I try to do is build python from src to get an appropriate static library. I can link it with my Qt toolchain (Mingw 4.6.3) and it compiles without error, but it fails to run. I double check it. All of my libs and tools are 32-bit. Thank you very much for your help. Regards, Mikl?s 2014-06-04 18:50 GMT+02:00 Erik H <ice.rikh(a)gmail.com>: > This is educational for me; to minimize pain, I settled on visual studio + > intel compiler long ago whenever I am coerced into windows development. > > You mentioned that did some surfing; did you encounter this page > <http://www.secker.nl/2012/03/08/setup-python-2-7-2-and-mingw-on-windows-xp/>? > Apparently, mingw should be able to link against the standard, visual > studio compiled python lib. Which would be a blessing for you if it > works... Are you trying to build 32-bit binaries linked against 64-bit > python libs by any chance? > > If you don't get any joy, I'll try setting up an official python binaries > + mingw environment on my windwoes system at home after work today or > tomorrow. Are you strictly targeting 2.7? > > -Erik > > > On Wed, Jun 4, 2014 at 3:07 AM, Mikl?s T?th <spiralfuzet(a)gmail.com> wrote: > >> Hi Erik, >> >> Thanks for the response. >> Yes I'm using makefile but I think the problem is different. >> Here is the gcc command that fails: >> gcc -c -fno-strict-aliasing -g -O2 -DNDEBUG -g -fwrapv -O3 -Wall >> -Wstrict-prototypes -I. -IInclude -I./Include -DPy_BUILD_CORE -o >> Python/asdl.o Python/asdl.c >> It has a -I./Include argument. >> >> So, I surf the Internet (a lot) and I found that at initial there were no >> autotool support for installing python from source. >> Later I found a Python 3.4 page were I could download an src setup for >> mingw installation. Unfortunatly that doesn't work either. >> So I reinstalled my Python and somehow I could link the library to my >> project. (I don't know how this possible, but the latest version of 2.7 >> works with my project. Blind luck I guess.) I could use >> PyRun_SimpleString but the PyRun_SimpleFileEx call crashes for some >> reason. >> Than I tried boost::python and it crashes aswell at the first object >> result = eval("5/2"); call. >> (I didn't forget to call Py_Initialize();). >> >> Any suggestions? >> >> Thanks, >> Mikl?s >> >> >> 2014-06-03 23:18 GMT+02:00 Erik H <ice.rikh(a)gmail.com>: >> >> Hi Mikl?s, >>> >>> Are you using a makefile? If so, it looks like you need to >>> add -I/cygdrive/e/INSTALL/python_src/Python-2.7.6/Include to the Makefile's >>> CFLAGS or CC variable, or somehow ensure that >>> -I/cygdrive/e/INSTALL/python_src/Python-2.7.6/Include is passed to the >>> compiler in any case. >>> >>> Regards, >>> Erik >>> >>> >>> On Mon, Jun 2, 2014 at 3:17 AM, Mikl?s T?th <spiralfuzet(a)gmail.com> >>> wrote: >>> >>>> Hi! >>>> >>>> Any updates on this? >>>> I get the following error: >>>> >>>> /cygdrive/e/INSTALL/python_src/Python-2.7.6 >>>> $ mingw32-make >>>> process_begin: CreateProcess(NULL, /usr/bin/mkdir -p Include, ...) failed. >>>> make (e=2): The system cannot find the file specified. >>>> mingw32-make: *** [Include/graminit.h] Error 2 >>>> >>>> but the corresponding file is there: >>>> >>>> /cygdrive/e/INSTALL/python_src/Python-2.7.6 >>>> $ ls Include/g*Include/genobject.h Include/graminit.h Include/grammar.h >>>> >>>> What am I missing? Any thoughts? >>>> >>>> Thanks, >>>> Mikl?s >>>> >>>> >>>> 2014-05-27 14:06 GMT+02:00 Mikl?s T?th <spiralfuzet(a)gmail.com>: >>>> >>>> Hi All, >>>>> I want to embed python in my c++ code using boost.python library. >>>>> As far as I understand I need python headers and libs. >>>>> So my python27.lib is "incompatible". I want to compile it from code >>>>> but I failed with mingw32. >>>>> Could you give me some advice, or links to achieve my goal? >>>>> I'm using gcc4.6.3 and qt 4.8.2 and boost 1.49 on windows 7. >>>>> Thanks, >>>>> Mikl?s >>>>> >>>> >>>> >>>> _______________________________________________ >>>> Boost-users mailing list >>>> Boost-users(a)lists.boost.org >>>> http://lists.boost.org/mailman/listinfo.cgi/boost-users >>>> >>> >>> >>> _______________________________________________ >>> Boost-users mailing list >>> Boost-users(a)lists.boost.org >>> http://lists.boost.org/mailman/listinfo.cgi/boost-users >>> >> >> >> _______________________________________________ >> Boost-users mailing list >> Boost-users(a)lists.boost.org >> http://lists.boost.org/mailman/listinfo.cgi/boost-users >> > > > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users >

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Boost program_options - is there a way to make abbreviations for short options
by tenspd137 . 06 Jun '14

06 Jun '14

Hi all, I was trying to figure out if there is a way to make the short options use more than one letter to create an abbrieviation. For example: desc.add_options() ("resolution","re","Choose resolution") ("raster-level,"rl","Chhose raster mode") .... I know that by convention and definition, short options are just -(letter), so that when you ask to print help, you get something like: -r [--resolution] arg -r [--raster-level] arg but I would like to find a way to have -re [--resolution] arg -rl [--raster-level] arg Point is, I have some options that start with the same letter, so being able to make short abbreivations or acronyms for them would be helpful. If this is possible, it isn't real clear to me how, and I haven't turned up much in google. Any suggestions? Thanks!

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Boost.Pimpl upcoming formal review (June 15 - June 24)
by Glen Fernandes 05 Jun '14

05 Jun '14

The formal review period of Boost.Pimpl by Vladimir Batov is scheduled to begin later this month, on June 15th, and will conclude on June 24th, and we welcome your participation. Vladimir's library provides a mechanism for implementing this popular, and still very relevant, idiom. To borrow his words from the documentation: [quote] In the domain of commercial large-scale software development the following design principles come to the fore: - component-based, modular and API-centered design, - separation of concerns, - implementation hiding, - minimization of compilation and component dependencies, - consistent and recognizable deployment and implementation patterns, multi-platform support. The Pimpl idiom can help great deal achieving those goals. It is a simple yet robust programming technique to minimize coupling via the separation of public interface and private implementation and then implementation hiding. [/quote] Please feel encouraged to browse the source code, documentation, and tests, before the review commences. Any feedback you have prior to the review period is also very appreciated. Source: https://github.com/yet-another-user/boost.pimpl/ Documentation: http://yet-another-user.github.io/boost.pimpl/ Download: https://github.com/yet-another-user/boost.pimpl/archive/master.zip If you would like to submit a review earlier, please provide your thoughts on the following topics: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? As well as information on the following questions: - Did you try to use the library? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? And most importantly: - Do you think the library should be accepted as a Boost library? Best, Glen

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is boost context supported on powerpc?-
by David Frank 05 Jun '14

05 Jun '14

Greetings, If it is supported how do I cross compile it from x86 machine, especially the assembler code part? Thanks, Frank

2 1

Sanity check please?: Boost 1_55_0 and building VS2012 static libs?
by g4＠novadsp.com 04 Jun '14

04 Jun '14

Revisiting Boost after a long absence. Any thoughts on the following problem(s)? W7x64 with VS2008,2010,2012 and 2013 installed. VS2012 preferred for regular use. Built with boostrap and b2 b2 -link=static -runtime-link=static -toolset=msvc-11.0. I compile a debug test app with /MTd and attempt to link with libboost_system-vc110-mt-gd-1_55.lib which is the only library close to matching the ABI tag specified here : http://www.boost.org/doc/libs/1_55_0/more/getting_started/windows.html#id46 Ensuing link errors are: 1>libboost_system-vc110-mt-gd-1_55.lib(error_code.obj) : error LNK2038: mismatch detected for '_ITERATOR_DEBUG_LEVEL': value '2' doesn't match value '0' in tcpproxy_server.obj 1>libboost_system-vc110-mt-gd-1_55.lib(error_code.obj) : error LNK2038: mismatch detected for 'RuntimeLibrary': value 'MDd_DynamicDebug' doesn't match value 'MT_StaticRelease' in tcpproxy_server.obj 1>LINK : warning LNK4098: defaultlib 'MSVCRTD' conflicts with use of other libs; use /NODEFAULTLIB:library Many thanks.

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Re: [Boost-users] [serialization] deserialized instance empty even though proper serialize methods called [Honeywell Internal]
by Hickman, Steve (AdvTech) 03 Jun '14

03 Jun '14

Classification: Honeywell Internal All serialize methods (except the base class serialize method) have as their first three lines code like this (with the appropriate BOOST_LOG_TRIVIAL(trace) << CLASS_METHOD << " called"; boost::serialization::void_cast_register<derived, base>( static_cast<derived *>(nullptr), static_cast<base *>(nullptr) ); ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(base); If that's what you're referring to, it didn't fix the problem --- Steve H. ============================================================================================================================================================================================================ This message classified as Honeywell Internal by Hickman, Steve (AdvTech) on Tuesday, June 03, 2014 at 3:34:21 AM. The above classification labels are in accordance with the Honeywell Corporate Classification Policy. The information contained in this electronic message is confidential and intended only for the use of the individual/entity named above, and the information may be privileged. If you, the reader of this message, are not the intended recipient or an employee or agent responsible to deliver this message to the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please immediately notify the sender and delete the original message. ============================================================================================================================================================================================================ From: Robert Ramey [mailto:robertmacleranramey@gmail.com] Sent: Sunday, June 01, 2014 11:22 AM To: boostusers(a)googlegroups.com Cc: robertmacleranramey(a)gmail.com; boost-users(a)lists.boost.org; Hickman, Steve (AdvTech) Subject: Re: [Boost-users] [serialization] deserialized instance empty even though proper serialize methods called On Saturday, May 31, 2014 2:50:35 PM UTC-7, Robert Ramey wrote: I woke up in the middle of the night. The "registration" base/derived pair is a side effect of class Base { virtual~Base(); template<class Archive); void serialize(Archive ar, const unsigned int version); }; class Derived { virtual~Derived(); template<class Archive); void serialize(Archive ar, const unsigned int version); }; template<class Archive); void Derived::serialize(Archive ar, const unsigned int version){ ar & boost::serialization::base_object<Base &>( *this); // side effect void_cast_register(Base, Derived) which updates the table when DLL is loaded } So I'm guessing that you're not calling the base class serialization so the Base/Derived pair isn't being registered. Solution: explicitly declare, define and call the Base class serialization even though it is empty. or explicitly invoke register void_cast::register base/derived - i forget the exact name. I'll be surprised if that doesn't solve your problem. RObert Ramey

1 0

trouble getting older version of boost to build
by David Toth (dtoth) 03 Jun '14

03 Jun '14

Hi. I am trying to build boost 1.41 (I need some of the libraries from it to compile some 3rd party software) and I am having issues. On CentOS 6.5 with the "Software Developer Workstation" installation (which comes with gcc 4.4.7 and g++ 4.4.7), I can build boost simply by running bootstrap.sh followed by running bjam. That creates all the libraries and then I can compile the other software that requires those libraries. Unfortunately, I can't use CentOS on the systems I am using. I reverted to trying it on CentOS just to see if I could get it to work on one version of Linux, thinking that it would be easy to then get it to work on another version. On Ubuntu, Fedora, and Debian (these are the versions of Linux I can use on the systems), I am unable to build the full set of libraries. After running bootstrap.sh and bjam, I am missing these files that were created on CentOS: libboost_thread.a‎ libboost_thread.so‎ libboost_thread.so.1.41.0‎ Without those files, the 3rd party software won't compile. Ubuntu, Fedora, and Debian come with more updated compilers and I read some place online that gcc 4.8 and g++ 4.8 have some issues with the old versions of boost, so I tried installing gcc 4.4.7 and g++ 4.4.7 and changing the symbolic links for gcc and g++ in /usr/bin/ to point to gcc 4.4.7 and g++ 4.4.7. Unfortunately, I am still unable to get the thread library to get created. I know boost 1.41 is old and I *might* be able to get away with using a version as recent as 1.49, but I have the same problems building that (and every version in between 1.41 and 1.49). Any help would be greatly appreciated. Thanks in advance. Dave

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Convert library review manager result
by Edward Diener 01 Jun '14

01 Jun '14

This is my analysis of the 'convert' library review and the result of whether the convert library should be accepted into Boost. Please read the entire analysis to understand my reasoning before reading the result. I would like to thank all of those who took part in the review and made comments. This includes Julian Gonggrip, Rob Stewart, Andrzej Krzemienski, Matus Chochlik, Jeroen Habraken, Erik Nelson, Hartmut Kaiser, Joel De Guzman, Thijs (M.A.) van den Berg, Roland Bock, Gavin Lambert, feverzsj, Paul Bristow, and alex. If I have missed anybody I do apologize. All comments were taken into account and all comments were intelligent and to the point. Naturally I would also like to than Vladimir Batov for patiently answering all comments and explaining and defending his library and his design decisions. For the most part I am going to focus on general issues rather than on the individuals who made them. Documentation issues: The documentation was too focused on explaining the library as it differed from lexical_cast. Vladimir Batov explained why this is so but I also agree that the documentation can be better by simply focusing on what the library provides in terms of functionality. Comments also mentioned that the current converters are not documented as well as the could be, and some commenters reflected that knowledge of how a particular converter works, including possible failures using that converter, is also needed despite the common library interface. The documentation did not provide enough information about the use of locales in the library. The reference section was very limited with not enough explanation. A reference built from doxygen comments in the source files would be better. A better explanation or example in the documentation for writing one's own converter was suggested. Although the Performance section in the documentation was fairly lengthy some commenters wanted to know why some things could not be tested. Others wanted more information about how convert performance compared to other convert-like implementations. In general I think most reviewers found the documentation adequate for understanding how to use the library but lacking in completeness. Vladimir Batov reflected that if the library were accepted into Boost he would then create more complete documentation and the above issues could be addressed. Implementation issues: As in most reviews most commenters did not look very deeply into the actual code but were happy to know how to use the library, and this is understandable for a review. There were a few pertinent comments however and I am just going to enumerate them. All macros should be prefix with BOOST_. My own addition to that is that all macros should be prefixed with BOOST_CONVERT_ to avoid any conflicts with other libraries. There should be a jamfile for running the tests. Also some full-blown examples of using the library in a simple program, along with the appropriate jamfile, would be helpful. Source code should contain spaces, not tabs. This is an easily fixed minor issue. As mentioned before doxygen comments in the public source are the usual Boost way of doing things. The main header file should be convert.hpp instead of api.h. Some includes were missing from the printf converter. Design issues: In the design of the library is where we have the most varying views. The major issue in discussing the design of the library for those who felt it was inadequate were the comments that using the library was too complicated, that the central function for invoking a conversion should be simpler to use. While all suggestions were well-argued I felt that a number of these differences were merely syntactical issues rather than issues that made the functionality easier to use. The main interface for using the library is: convert<output_type>::from(input_value, converter) Vladimir Batov had asserted during the review that this could be simplified further by removing the need for the 'from::' part of the signature which would make the syntax simpler. Some reviewers did not like the name 'convert' and offered substitutions, others wanted the default value, currently specified as '.value_or(default)', to be specified as a direct input parameter, others wanted the converter itself which is an input parameter to be specified via another syntax. All of these are too me syntactical issues and no resolution could possibly please everybody but it is understandable that different reviewers have different syntactical preferences. More to the point were some changes in actual functionality. The three most important involved the return value, type requirements for the output type, and the use of a default converter. Considering each in its turn: 1) The return value is some form of 'optional', with the idea of using boost::optional if it meets all the requirements needed by the 'convert' library. A number of people wanted the actual value returned without having to append .value() to the convert signature to get it. They were also concerned with the performance overhead of having to create an optional value as the immediate return value. It was also suggested that while the current convert syntax might be fine, some alternatives directly returning the value, for those who like maximum simplicity, might be possible. 2) The type requirements for the output type are default constructible and copy constructible. A number of reviewers felt that if a non-const reference were passed to the convert function as an output instance then the type requirements would not have to be met. However the type requirements of some of the underlying converters might be affected by this and the documentation does explain how to work around the default constructible requirement, but I still do understand the reasoning behind this possibility. 3) A number of reviewers wanted a default converter to be used but there was hardly an agreement on what this default converter should be, some favoring lexical_cast, others favoring stringstream, and no doubt others might want something else. Nevertheless providing a default constructor interface, possible with a macro defined a compile time, seems like it might be doable. There was further discussion about the actual callable signature for a plug-in converter. Here there was less contention about the interface, which is currently a callable with a signature of: template<typename TypeOut, typename TypeIn> bool operator()(TypeIn const& value_in, TypeOut& result_out) const; Vladimir Batov did suggest some possible alternatives and there was a discussion with a number of reviewers about alternatives that seem implementable. This also ties into the concern of some reviewers that it should be straightforward to create one's own converters with minimum restrictions on the input and output types, as well as minimum performance overhead. Votes: A number of reviewers made comments but offered no final vote on whether or not the conversion library should be accepted into Boost. Some reviewers offered a Yes vote, but heavily based on changes they want to see. I will attempt to tabulate them here: YES votes: Christopher Kormanyos Paul Bristow Julian Gonggrip ( with some reservations which Vladimir Batove has met or may easily meet ) Andrzej Krzemienski Matus Chochlik YES, conditionally but otherwise NO if conditions are not met, which the current version does not meet] Jeroen Habraken Roland Bock alex NO Rob Stewart Final Decision: Among those who voted YES conditionally but otherwise NO there was a general consensus including Vladimir Batov, the 'convert' library creator, and some of the others that an attempt could be made to satisfy some of the conditions for simplification and/or functionality they desired. My decision, based on the votes as I interpret them, is that the convert library is ACCEPTED into Boost. While a perfect design is impossible I believe that the design of the library is an adequate starting point for a general-purpose conversion framework and that the design could change incrementally enough to satisfy some of the qualms of those who might not find it as initially useful as they have hoped, while still maintaining the central framework which Vladimir Batov has created. Furthermore I believe that others have reflected that a general-purpose conversion library would be very useful if it were flexible enough to support plug-in converters created by programmers, as the 'convert' library does. I realize that what is essentially a 5 to 4 vote in favor of the library is not an overwhelming consensus by any means but I feel that 3 of those 4 NO votes are predicated on wishes for possible changes to the 'convert' library which may yet be met before the library gets officially added to an upcoming Boost release. Since I have accepted the library based on the votes and my interpretation of the issues I would like to encourage those who feel that some alternate designs could be implemented as part of the 'convert' library to work with Vladimir Batov, if he is agreeable, to add those alternatives to the library. Nonetheless it is his library and he would be the final arbiter of any decisions reached. I would like to encourage the view, however, that the current design is what has been voted in by others as the 'convert' library so that any changes made to it as it is added to Boost should be incremental additions which minimally change what others see as an acceptable library.

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