May 2013 - 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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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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[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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Problems calling make_reversed_graph in a call to dijkstra from version 1.48
by Berit Dangaard Brouer 08 Apr '14

08 Apr '14

Hi, First of all thank you for providign the boost BGL library. I use it extensively. I am having some problems with some code, that works just fine using boost version 1.46, but cannot compile using version 1.48 and higher. I have a Bidirectional Graph using bundled properties defined as: struct Port { Port(int index=-1, int type=-1, int port_code=0, string UN="NN", string name="NN", int service_id=-1 ): m_index(index), m_type(type), m_port_code( port_code), UNLOCODE(UN), m_name(name), m_service_id(service_id) {} int m_index; int m_type;//0 port, 1 port call int m_port_code; string UNLOCODE; string m_name; int m_service_id; }; struct Edge { Edge( int id=-1, int type=-1, double weight=0.0, double cost=0.0, double dual_cost=0.0, double util=0.0, double cap=0.0, double r_cap=0.0 ) : m_idx(id), m_type(type), m_weight(weight) , m_cost(cost), m_dual_cost(dual_cost), m_utilization(util), m_capacity(cap), m_res_cap(r_cap) {} unsigned int m_idx; int m_type;//0 is load edge, 1 is voyage edge, 2 forfeited edge (commodity link) double m_weight; //distance double m_cost; //cost - only on load/unload/transhipment edges double m_dual_cost; double m_utilization; double m_capacity; double m_res_cap; //residual capacity }; //Graph typedef adjacency_list< vecS , vecS , bidirectionalS, Port, Edge> mcf_graph; I am trying to make a call to dijkstra on a reversed graph as follows: (the reversed graph is also a filtered graph, but I do not think this is an issue: dijkstra_shortest_paths (make_reverse_graph(fg), before_p, predecessor_map ( &p[0] ).distance_map ( &d[0] ).weight_map ( get ( &Edge::m_weight, fg) ).vertex_index_map ( get ( vertex_index,fg ) ) ); which works fine in 1.46, but it seems in 1.48 I can no longer use make_reverse_graph(<mcf_graph&>) (returning a reverse graph) with the bundled properties from fg. and I get the error (compressed summary - full details attached) usr/include/boost/property_map/property_map.hpp:354:56: error: no match for 'operator[]' in '((const boost::bundle_property_map<boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS, Port, Edge>, boost::detail::edge_desc_impl<boost::bidirectional_tag, long unsigned int>, Edge, double>&)pa)[k]' /usr/include/boost/property_map/property_map.hpp:354:56: note: candidate is: In file included from /usr/include/boost/graph/adjacency_list.hpp:44:0, from /home/chrkr/git/lsndp/include/ipheuristic.h:36, from /home/chrkr/git/lsndp/src/ipheuristic.cpp:29: /usr/include/boost/graph/properties.hpp:399:15: note: T& boost::bundle_property_map<Graph, Descriptor, Bundle, T>::operator[](boost::bundle_property_map<Graph, Descriptor, Bundle, T>::key_type) const [with Graph = boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS, Port, Edge>; Descriptor = boost::detail::edge_desc_impl<boost::bidirectional_tag, long unsigned int>; Bundle = Edge; T = double; boost::bundle_property_map<Graph, Descriptor, Bundle, T>::reference = double&; boost::bundle_property_map<Graph, Descriptor, Bundle, T>::key_type = boost::detail::edge_desc_impl<boost::bidirectional_tag, long unsigned int>] /usr/include/boost/graph/properties.hpp:399:15: note: no known conversion for argument 1 from 'const boost::detail::reverse_graph_edge_descriptor<boost::detail::edge_desc_impl<boost::bidirectional_tag, long unsigned int> >' to 'boost::bundle_property_map<boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS, Port, Edge>, boost::detail::edge_desc_impl<boost::bidirectional_tag, long unsigned int>, Edge, double>::key_type {aka boost::detail::edge_desc_impl<boost::bidirectional_tag, long unsigned int>}' From various sources I understand that as of 1.48 reverse graph is no longer an image of the graph, but another object, where I need the actual property maps and the property maps of the reversed graph, but I did not get much wiser on how to call dijkstra with the reversed graph given these new description. I tried defining the reverse graph as a separate object reverse_graph<mcf_graph> r_fg=reverse_graph(fg); dijkstra_shortest_paths (r_fg), before_p, predecessor_map ( &p[0] ).distance_map ( &d[0] ).weight_map ( get ( &Edge::m_weight, r_fg) ).vertex_index_map ( get ( vertex_index, r_fg ) ) ); indicating that I am not getting the right properties for the reverse graph: equired from here /usr/include/boost/graph/properties.hpp:420:44: error: no type named 'vertex_bundled' in 'class boost::reverse_graph<boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS, Port, Edge> >' /usr/include/boost/graph/properties.hpp:421:42: error: no type named 'edge_bundled' in 'class boost::reverse_graph<boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS, Port, Edge> >' /usr/include/boost/graph/properties.hpp:425:7: error: no type named 'vertex_bundled' in 'class boost::reverse_graph<boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS, Port, Edge> >' /usr/include/boost/graph/properties.hpp:429:7: error: no type named 'vertex_bundled' in 'class boost::reverse_graph<boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS, Port, Edge> >' /usr/include/boost/graph/properties.hpp:432:70: error: no type named 'vertex_bundled' in 'class boost::reverse_graph<boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS, Port, Edge> >' /usr/include/boost/graph/properties.hpp:434:7: error: no type named 'vertex_bundled' in 'class boost::reverse_graph<boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS, Port, Edge> >' /home/chrkr/git/lsndp/src/ipheuristic.cpp:939:132: error: no matching function for call to 'get(double Edge::*, boost::reverse_graph<boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS, Port, Edge> >&)' /home/chrkr/git/lsndp/src/ipheuristic.cpp:939:132: note: candidates are: In file included from /usr/include/boost/graph/adjacency_list.hpp:36:0, from /home/chrkr/git/lsndp/include/ipheuristic.h:36, from /home/chrkr/git/lsndp/src/ipheuristic.cpp:29: /usr/include/boost/property_map/property_map.hpp:179:19: note: template<class T> const T& get(const T*, std::ptrdiff_t) /usr/include/boost/property_map/property_map.hpp:179:19: note: template argument deduction/substitution failed: /home/chrkr/git/lsndp/src/ipheuristic.cpp:939:132: note: mismatched types 'const T*' and 'double Edge::*' In file included from /usr/include/boost/graph/graphviz.hpp:25:0, from /home/chrkr/git/lsndp/include/data.h:19, from /home/chrkr/git/lsndp/include/ipheuristic.h:46, from /home/chrkr/git/lsndp/src/ipheuristic.cpp:29: /usr/include/boost/property_map/dynamic_property_map.hpp:322:1: note: template<class Key> std::string boost::get(const string&, const boost::dynamic_properties&, const Key&) /usr/include/boost/property_map/dynamic_property_map.hpp:322:1: note: template argument deduction/substitution failed: Is the problem the bundled properties from the original graph or ? -- Best Regards, Ph.D. Berit Dangaard Brouer Post Doc. DTU Management Engineering, Management Science Technical University of Denmark Department of Management Engineering Produktionstorvet, Bygning 426 2800 Kgs. Lyngby blof(a)dtu.dk <mailto:blof@man.dtu.dk> www.ms.man.dtu.dk <http://www.ms.man.dtu.dk> http://www.maersk.com/innovation/leadingthroughinnovation/enerplan/ Please read about the ENERPLAN project here <http://www.maersk.com/innovation/leadingthroughinnovation/enerplan/>

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[asio] resolver::cancel() problem
by Matthew Edwards 14 Mar '14

14 Mar '14

In my application (and a separate test program) it seems as though the cancel() function on the resolver does not work as intended. For async resolves, the cancel functionality should abort them immediately and pass an 'operation aborted' error code to the callback handler. In my tests, I will resolve an invalid domain (this causes the resolve to take a few seconds, to demonstrate the problem), sleep for 100ms, then call cancel on the resolver object. No cancelling actually occurs, and the callback is simply triggered after a few seconds with a "No host found" error code, not the expected operation aborted. Has anyone experienced this before, or know how I might be using the resolver incorrectly?

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Server failing when BOOST_ASIO_ENABLE_HANDLER_TRACKING is active
by Gonzalo Garramuno 22 Jan '14

22 Jan '14

Trying to track down when the socket closes on my program, I turned on asio debugging. Server fails when BOOST_ASIO_ENABLE_HANDLER_TRACKING is active. Its stack trace is: g Scanning dependencies of target mrViewer [ 9%] Building CXX object mrViewer/src/CMakeFiles/mrViewer.dir/core/mrvServer.o Linking CXX executable ../../../bin/mrViewer [100%] Built target mrViewer # gga@gga-laptop1 /media/Linux/code/applications/mrViewer # mar ene 01 10:04 [8] $ mrViewer /media/Linux/movies/Tangled.mov [opengl] Using hardware shader profile: NVidia NV30 [opengl] mrViewer supports YUV images through shaders. [psql] Connected to database 'assets2d_development'. The code: boost::asio::io_service io_service; tcp::endpoint listen_endpoint(tcp::v4(), s->port); server rp(io_service, listen_endpoint, s->ui); io_service.run(); fails with: @asio|1357088683.200673|0|socket@0x7f303d8d2d00.close Got signal 11, faulty address is 0x1, from 0x4d222a [bt] Execution path: [bt] mrViewer(_ZN5boost4asio6detail15task_io_service16shutdown_serviceEv+0x3a) [0x4d222a] [bt] mrViewer(_ZN5boost4asio6detail15task_io_service16shutdown_serviceEv+0x3a) [0x4d222a] [bt] mrViewer() [0x4dd2c9] [bt] mrViewer(_ZN3mrv13server_threadEPKNS_10ServerDataE+0x408) [0x4e0e58] [bt] /usr/lib/libboost_thread.so.1.48.0(+0xdda9) [0x7f304e191da9] [bt] /lib/x86_64-linux-gnu/libpthread.so.0(+0x7e9a) [0x7f304f7f0e9a] [bt] /lib/x86_64-linux-gnu/libc.so.6(clone+0x6d) [0x7f304da1ccbd] without the #define the code works reliably except sometimes the socket closes unexpectedly.

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Question for Boost.Threads and Boost.Test
by young 20 Jan '14

20 Jan '14

According to Boost document, Boost.Test can only be statically linked. Boost.Threads can only be dynamically linked. Then what boost_unit_test_framework-vc100-mt-1_53.lib for? Is it for dynamically linked dll? what libboost_thread-vc100-mt-1_53.lib for? Is it for static library? -- View this message in context: http://boost.2283326.n4.nabble.com/Question-for-Boost-Threads-and-Boost-Tes… Sent from the Boost - Users mailing list archive at Nabble.com.

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[Test] Where to learn about boost::itest::mock_object?
by Mateusz Loskot 20 Jan '14

20 Jan '14

Hi, I'm looking for a simple mocking library to use together with Boost.Test. There is Turtle (aka Boost.Mock) and googlemock. During retrospection of the big thread on Boost.Test future [1], I found this curious post by Gennadiy [2] about mock_object. I had no idea such facility lives in Boost.Test and it looks it's been there for very long time. I can't find any documentation about mock_oboject, only a couple of examples. So, I have a few questions: Is the mock_object an internal feature or is it dedicated (and ready) to use by Boost.Test users? What are basic features of this mocking facility? How does it compare to Turtle or googlemock? [1] http://thread.gmane.org/gmane.comp.lib.boost.devel/234297 [2] http://thread.gmane.org/gmane.comp.lib.boost.devel/234297/focus=234621 [3] find /home/mloskot/dev/boost/_svn/trunk/libs/test -type f | xargs grep mock_object Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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Does Boost.Test cover 'golden file approach'?
by Journeyer J. Joh 13 Jan '14

13 Jan '14

Hello, I know almost nothing about 'golden file approach'. http://weblogs.java.net/blog/alexeyp/archive/2007/02/testing_command.html >From this blog, you can find the term 'golden file approach'. I want to know if Boost.Test cover this kind of testing. Can I implement 'golden file approach' with Boost.Test? If so please provide me more information about it. Thank you very much. ---------------------------------------- Journeyer J. Joh o o s a p r o g r a m m e r a t g m a i l d o t c o m ----------------------------------------

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[boost.test] How to register custom exception for auto test?
by Jörg Becker 13 Jan '14

13 Jan '14

Hi, I'm using the test library of boost 1.49.0 for my unit tests. It works fine so fare, but if my program throws an error, I get the default error message unknown location(0): fatal error in "excption1_test": unknown type, witch hides the original error message. I tried to register an error translator, but without success. Here is what I tried (modified test/test/custom_exception_test.cpp to use auto test with global fixture): #define BOOST_TEST_MODULE "boost test custom_exception_test" #include <boost/test/unit_test.hpp> #include <boost/test/unit_test_monitor.hpp> using namespace boost::unit_test; BOOST_AUTO_TEST_SUITE( custom_exception_testsuite ) struct my_exception1 { explicit my_exception1( int res_code ) : m_res_code( res_code ) {} int m_res_code; }; void throw_my_exception1() { throw my_exception1( 12 ); } void my_exception1_translator( my_exception1 ) { BOOST_TEST_MESSAGE( "Caught my_exception1" ); } class my_config { public: my_config () { unit_test_monitor.register_exception_translator<my_exception1>( &my_exception1_translator ); } }; BOOST_GLOBAL_FIXTURE( my_config ) BOOST_AUTO_TEST_CASE( excption1_test ) { throw_my_exception1(); } BOOST_AUTO_TEST_SUITE_END() Can anybody tell me what I'm missing? Thanks, Jörg

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using boost with net-snmp
by moshe levi 12 Sep '13

12 Sep '13

I wrote an example on how to integrate net-snmp with boost. please checkout http://blog-moshe.blogspot.co.il/

2 1

[BGL] Having a cost function as weight map
by Maxime van Noppen 06 Sep '13

06 Sep '13

Hi, I can't find how to do this pretty basic thing : having a function instead of a field to compute the cost of edges for various path finding algorithms. I couldn't find the answer in the documentation and Google was of no help. Did I miss something obvious ? Example : ------------------- #include <boost/graph/dijkstra_shortest_paths.hpp> #include <boost/graph/graph_traits.hpp> #include <boost/graph/adjacency_list.hpp> struct my_edge { double cost() const { return cost_ * 2; } double cost_; }; struct my_node { }; int main() { typedef boost::adjacency_list< boost::vecS, boost::vecS, boost::directedS, my_node, my_edge > graph_t; typedef boost::graph_traits<graph_t>::vertex_descriptor vertex_t; graph_t graph; vertex_t v /*= ... */; using boost::weight_map; // Works : boost::dijkstra_shortest_paths(graph, v, weight_map(boost::get(&my_edge::cost_, graph))); // Doesn't compile : //boost::dijkstra_shortest_paths(graph, v, // weight_map(boost::get(&my_edge::cost, graph))); } ------------------- Thanks ! -- Maxime

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Identify cycles in a undirected graph
by NsPx 20 Aug '13

20 Aug '13

Hi all, I use undirected_dfs to detect all cycles in a undirected graph. I detect a cycle with DFSVisitor.back_edge(e,g) but how can I get the list of vertices defining this cycle ? Thanks by advance

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[exception] exception_ptr missing virtual base parameters
by Michael Caisse 13 Jul '13

13 Jul '13

The basic problem I'm experiencing is that getting an exception_ptr results inherited parameters getting lost when virtual inheritance is used. The code below demonstrates a simple example. "bar" is lost in the print. Changing derived_except to be: struct derived_except : base_except { int i; }; will cause the inherited values to be copied into the exception_ptr; however, this has all the standard problems associated that come with not using virtual inheritance. This looks like a bug to me. The C++11 equivalent behaves has expected and inherited values are maintained in the exception_ptr. Any thoughts? michael -------------- boost::exception_ptr version -------------- #include <boost/exception/all.hpp> #include <string> #include <iostream> struct base_except { std::string s; }; struct derived_except : virtual base_except { int i; }; int main() { derived_except e; e.i = 8; e.s = "bar"; boost::exception_ptr ptr = boost::copy_exception(e); try { boost::rethrow_exception(ptr); } catch(derived_except & e) { std::cout << "derived_except: " << e.s << " " << e.i << std::endl; } catch(...) {} return 0; } -------------- c++11 version --------------------- #include <exception> #include <string> #include <iostream> struct base_except { std::string s; }; struct derived_except : virtual base_except { int i; }; int main() { derived_except e; e.i = 8; e.s = "bar"; std::exception_ptr ptr = std::make_exception_ptr(e); try { std::rethrow_exception(ptr); } catch(derived_except & e) { std::cout << "derived_except: " << e.s << " " << e.i << std::endl; } catch(...) {} return 0; } -- Michael Caisse ciere consulting ciere.com

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

09 Jul '13

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

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ASIO: Problem with building boost 1.53 ASIO examples under cygwin
by mschulze＠ivs.cs.ovgu.de 27 Jun '13

27 Jun '13

Hi all, I tried building boost 1.53 ASIO examples under cygwin and it didn't worked with bjam or b2 respectively. Then I used "bjam -n" to get the invoked commands in order to further track down the issue. I end up with the following command to compile an example "g++" -ftemplate-depth-128 -O0 -fno-inline -Wall -g -mthreads -DBOOST_ALL_NO_LIB=1 -DBOOST_CHRONO_DYN_LINK=1 -DBOOST_SYSTEM_DYN_LINK=1 -DBOOST_SYSTEM_NO_DEPRECATED -DBOOST_THREAD_BUILD_DLL=1 -DBOOST_THREAD_POSIX -DBOOST_THREAD_USE_DLL=1 -I"../../../.." -o "blocking_udp_echo_server" "blocking_udp_echo_server.cpp" -D__USE_W32_SOCKETS -D_WIN32_WINNT=0x0501 ../../../../bin.v2/libs/thread/build/gcc-4.5.3/release/link-static/threading-multi/libboost_thread.a ../../../../bin.v2/libs/system/build/gcc-4.5.3/release/link-static/threading-multi/libboost_system.a -lws2_32 -lmswsock and I got the following errors: In file included from ../../../../boost/asio/detail/impl/posix_tss_ptr.ipp:24:0, from ../../../../boost/asio/detail/posix_tss_ptr.hpp:77, from ../../../../boost/asio/detail/tss_ptr.hpp:27, from ../../../../boost/asio/detail/call_stack.hpp:20, from ../../../../boost/asio/impl/handler_alloc_hook.ipp:19, from ../../../../boost/asio/handler_alloc_hook.hpp:80, from ../../../../boost/asio/detail/handler_alloc_helpers.hpp:22, from ../../../../boost/asio/detail/bind_handler.hpp:19, from ../../../../boost/asio/detail/wrapped_handler.hpp:18, from ../../../../boost/asio/io_service.hpp:24, from ../../../../boost/asio/basic_io_object.hpp:19, from ../../../../boost/asio/basic_socket.hpp:19, from ../../../../boost/asio/basic_datagram_socket.hpp:20, from ../../../../boost/asio.hpp:20, from blocking_udp_echo_server.cpp:13: ../../../../boost/asio/error.hpp:77:17: error: a function call cannot appear in a constant-expression ../../../../boost/asio/error.hpp:130:15: error: a function call cannot appear in a constant-expression ../../../../boost/asio/error.hpp:135:19: error: a function call cannot appear in a constant-expression ../../../../boost/asio/error.hpp:149:23: error: a function call cannot appear in a constant-expression ../../../../boost/asio/error.hpp:163:15: error: a function call cannot appear in a constant-expression ../../../../boost/asio/error.hpp:244:45: warning: boost::asio::error::system_category defined but not used ../../../../boost/asio/error.hpp:246:45: warning: boost::asio::error::netdb_category defined but not used ../../../../boost/asio/error.hpp:248:45: warning: boost::asio::error::addrinfo_category defined but not used ../../../../boost/asio/error.hpp:250:45: warning: boost::asio::error::misc_category defined but not used ../../../../boost/asio/detail/winsock_init.hpp:78:30: warning: boost::asio::detail::winsock_init_instance defined but not used The error messages boils down to the use of "__MSABI_LONG(x)" within an enumeration definition. __MSABI_LONG is a macro that has to be resolved during the cpp run but isn't but it seems not to be known at this point. I also tested the boost version 1.52 and there are none of these issues and it worked like it is intended. Best regards, Michael

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Comparison boost spirit and ANTLR
by Olivier Austina 17 Jun '13

17 Jun '13

Hi, I would like to choose a parser. I would like to use a parser for text processing (natural language text). Which parser is suited in this case. In general which are the benefit to use boost spirit instead of ANTLR or ANTLR instead of boost spirit. Thank you. -- Regards Austina

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[thread] synchronized_value: value and move semantics
by Vicente J. Botet Escriba 08 Jun '13

08 Jun '13

Hi, boost::synchronized_value (not released yet [1][2][3]) is based on [4]. See below part of this paper adapted to the Boost.Thread interface. Currently boost::synchronized_value is in addition Copyable and Swappable. I was wondering if it is worth adding value and move semantics to synchronized_value. Making it EqualityComparable, LessThanComparable and Movable if the underlying type satisfy these requirements will allow to store them on a Boost.Container/C++11 container. Do you see something completely wrong with this addition? Has some of you had a need for this? Could you share the context? Best, Vicente [1] https://svn.boost.org/svn/boost/trunk/boost/thread/synchronized_value.hpp [2] https://svn.boost.org/svn/boost/trunk/libs/thread/example/synchronized_valu… [3] https://svn.boost.org/svn/boost/trunk/libs/thread/example/synchronized_pers… [4] "Enforcing Correct Mutex Usage with Synchronized Values" by Anthony Williams http://www.drdobbs.com/cpp/enforcing-correct-mutex-usage-with-synch/2252002… ------------- [section The Problem with Mutexes] The key problem with protecting shared data with a mutex is that there is no easy way to associate the mutex with the data. It is thus relatively easy to accidentally write code that fails to lock the right mutex - or even locks the wrong mutex - and the compiler will not help you. std::mutex m1; int value1; std::mutex m2; int value2; int readValue1() { boost::lock_guard<boost::mutex> lk(m1); return value1; } int readValue2() { boost::lock_guard<boost::mutex> lk(m1); // oops: wrong mutex return value2; } Moreover, managing the mutex lock also clutters the source code, making it harder to see what is really going on. The use of synchronized_value solves both these problems - the mutex is intimately tied to the value, so you cannot access it without a lock, and yet access semantics are still straightforward. For simple accesses, synchronized_value behaves like a pointer-to-T; for example: boost::synchronized_value<std::string> value3; std::string readValue3() { return *value3; } void setValue3(std::string const& newVal) { *value3=newVal; } void appendToValue3(std::string const& extra) { value3->append(extra); } Both forms of pointer dereference return a proxy object rather than a real reference, to ensure that the lock on the mutex is held across the assignment or method call, but this is transparent to the user. [endsect] [/The Problem with Mutexes] [section Beyond Simple Accesses] The pointer-like semantics work very well for simple accesses such as assignment and calls to member functions. However, sometimes you need to perform an operation that requires multiple accesses under protection of the same lock, and that's what the synchronize() method provides. By calling synchronize() you obtain an strict_lock_ptr object that holds a lock on the mutex protecting the data, and which can be used to access the protected data. The lock is held until the strict_lock_ptr object is destroyed, so you can safely perform multi-part operations. The strict_lock_ptr object also acts as a pointer-to-T, just like synchronized_value does, but this time the lock is already held. For example, the following function adds a trailing slash to a path held in a synchronized_value. The use of the strict_lock_ptr object ensures that the string hasn't changed in between the query and the update. void addTrailingSlashIfMissing(boost::synchronized_value<std::string> & path) { boost::strict_lock_ptr<std::string> u=path.synchronize(); if(u->empty() || (*u->rbegin()!='/')) { *u+='/'; } } [endsect] [/Beyond Simple Accesses] [section Operations Across Multiple Objects] Though synchronized_value works very well for protecting a single object of type T, nothing that we've seen so far solves the problem of operations that require atomic access to multiple objects unless those objects can be combined within a single structure protected by a single mutex. One way to protect access to two synchronized_value objects is to construct a strict_lock_ptr for each object and use those to access the respective protected values; for instance: synchronized_value<std::queue<MessageType> > q1,q2; void transferMessage() { strict_lock_ptr<std::queue<MessageType> > u1 = q1.synchronize(); strict_lock_ptr<std::queue<MessageType> > u2 = q2.synchronize(); if(!u1->empty()) { u2->push_back(u1->front()); u1->pop_front(); } } This works well in some scenarios, but not all - if the same two objects are updated together in different sections of code then you need to take care to ensure that the strict_lock_ptr objects are constructed in the same sequence in all cases, otherwise you have the potential for deadlock. This is just the same as when acquiring any two mutexes. In order to be able to use the dead-lock free lock algorithms we need to use instead unique_lock_ptr, which is Lockable. synchronized_value<std::queue<MessageType> > q1,q2; void transferMessage() { unique_lock_ptr<std::queue<MessageType> > u1 = q1.unique_synchronize(boost::defer_lock); unique_lock_ptr<std::queue<MessageType> > u2 = q2.unique_synchronize(boost::defer_lock); boost::lock(u1,u2); // dead-lock free algorithm if(!u1->empty()) { u2->push_back(u1->front()); u1->pop_front(); } } [endsect] [/Operations Across Multiple Objects]

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Using boost from XCODE 4.6.1 - what are the proper build settings?
by B Hart 01 Jun '13

01 Jun '13

I downloaded boost 1.53 and extracted to Users/user/Desktop/boost_1_53_0 I built boost as static libraries following instructions at: http://libcinder.org/docs/v0.8.5/_cinder_boost.html I changed XCODE's "Build Settings" "Header Search Paths" to /Users/user/Desktop/boost_1_53_0 as well as the "Library Search Paths" to Users/user/Desktop/boost_1_53_0/stage/lib Then I build and get errors: The first error I'm getting is "has_binary_operator.hpp" Parse issue Expected member name or ';' after declaration specifiers at the line: template < typename Lhs, typename Rhs > struct operator_exists { ... Does anyone have tips for what the build settings should be? The project contains some files that are cocoa/objective C (.m) and others that are C++(.mm) using boost. I'm completely new to trying to use boost under OSX mountain lion and XCODE 4.6.1.

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[mpl] Using max_element inside a fold while constructing a vector
by Brendon Costa 01 Jun '13

01 Jun '13

Hi, I have been using boost.mpl for the first time recently and have solved a number of tasks with boost.mpl now but have a problem with a bit of code I thought should be working. What is wrong with this bit of code using boost.mpl? typedef vector<int_<0>, int_<3>, int_<2> > v1; // I want to use max_element on a vector I am in the process of constructing using a fold typedef typename fold<v1, vector<int_<0> >, push_back<_1, deref<max_element<_1>::type >::type> >::type v2; // This code below compiles and runs fine to illustrate that max_element on a vector works, but is not what I am after. // I thought _1 in the max_element above would be a vector just as v1 below is, but the one below works and the one above does not. // typedef typename fold<v1, vector<int_<0> >, push_back<_1, deref<max_element<v1>::type >::type> >::type v2; I know this code is only going to create v2 like [0, 0, 0, 0] in this case but this is a smaller part of a larger expression that is failing and I cut it down to the minimum to show the problem at hand. In case it is useful I am using gcc 4.5.3 and boost 1.50

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[Thread] Can't compile package_task code with 1.54
by Szymon Gatner 01 Jun '13

01 Jun '13

Hi, I just tried to compile my 1.52- based code with 1.54 beta and run into package_task compilation issue. In 1.52 I was using BOOST_THREAD_VERSION=3 define but with 1.54 I complied with =4. Test program: #define BOOST_THREAD_VERSION 4 #include <boost/thread/future.hpp> #include <boost/function.hpp> struct MyFunc { void operator()()const {} }; int main() { boost::function<void()> f; MyFunc mf; boost::packaged_task<void()> t1(f); // error 1 boost::packaged_task<void()> t2(mf); // error 2 } error 1 being: d:\devel\boost_1_54_0_beta1\boost\thread\future.hpp(2848): error C2664: 'boost::detail::task_object<F,R>::task_object(boost::detail::task_object<F,R> &)' : cannot convert parameter 1 from 'boost::function<Signature>' to 'boost::detail::task_object<F,R> &' and error 2 similarly: d:\devel\boost_1_54_0_beta1\boost\thread\future.hpp(2848): error C2664: 'boost::detail::task_object<F,R>::task_object(boost::detail::task_object<F,R> &)' : cannot convert parameter 1 from 'MyFunc' to 'boost::detail::task_object<F,R> &' (I tried with custom functor because I thought maybe error was related to boost function) Compiling with Visual Studio 2012 Update 3 Regards, Szymon Gatner

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[1.54.0] Beta Release Candidates available
by Marshall Clow 01 Jun '13

01 Jun '13

Release candidate files for 1.54.0 beta 1 are available at http://boost.cowic.de/rc/ As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. This helps ensure the candidates build OK before we push them out to SourceForge. The files (and associated md5s) are: 31266b7dcc6f557ad839e4e87317cd6e *boost_1_54_0_beta1_rc1.tar.gz fbf7be9cbaf9ea6fb21ae73d0c17100d *boost_1_54_0_beta1_rc1.tar.bz2 7de4299ab69c941e83fe3fc46dddc15f *boost_1_54_0_beta1_rc1.zip c73e5118ff585d9f1d68542f96a0758a *boost_1_54_0_beta1_rc1.7z Thanks, --The release managers

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