March 2014 - Boost-users - lists.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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Fix for annoying bug / library maintenance
by Filip Konvička 30 May '14

30 May '14

Hi, https://svn.boost.org/trac/boost/ticket/4964 This is out there for years. To me this seems to be clearly explained and a fix is provided, but apparently all bugs assigned to 'bgubenko' aren't monitored (for years there has been no reaction). So is there a way of getting the fix ever applied? Or are such unmaintained libraries just doomed to eventually die, despite the efforts of the people reporting bugs and posting patches? Thanks, Filip

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Boost test and openmpi
by Martin Vymazal 21 May '14

21 May '14

Hello, I have the following code: #define BOOST_TEST_DYN_LINK #define BOOST_TEST_MODULE mpi_functionality #include <boost/test/unit_test.hpp> #include "mpi.h" struct MPI_Functionality_Fixture { MPI_Functionality_Fixture() { m_argc = boost::unit_test::framework::master_test_suite().argc; m_argv = boost::unit_test::framework::master_test_suite().argv; } int m_argc; char** m_argv; }; BOOST_FIXTURE_TEST_SUITE( MPI_Functionality_TestSuite, MPI_Functionality_Fixture ) BOOST_AUTO_TEST_CASE( mpi_functionality_parenv_init ) { MPI_Init(&m_argc,&m_argv); } BOOST_AUTO_TEST_CASE( mpi_functionality_parenv_finalize ) { MPI_Finalize(); } BOOST_AUTO_TEST_SUITE_END() The code compiles fine, but I have the following problem when I try to run it. When I run as 'mpirun ./my_executable' or 'mpirun -np 3 ./my_executable' everything goes fine. On the other hand, when I run as ./my_executable I get the following error: unknown location(0): fatal error in "mpi_functionality_parenv_finalize": unrecognized signal Outside of Boost, it is perfectly possible to write a program which calls MPI_Init and MPI_Finalize and it does not have to be used with mpirun. I wonder if this (different) behavior of Boost test is normal. I did not find any remarks regarding Boost test and mpi in the tutorial. Best regards, Martin Vymazal

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"Trac thinks your submission might be Spam. To prove otherwise please provide a response to the following."
by Nico Schlömer 16 May '14

16 May '14

Hi all, I would like to make contributions to Boost on trac <https://svn.boost.org/trac/boost>, but whenever I would like to make comment a bug report, it gets recognized as spam, and I'm redirected to a captcha-page that I think should contain a captcha, but does _not_ <https://svn.boost.org/trac/boost/captcha#trac-add-comment>. Any hints? Cheers, Nico

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conflicting intmax_t definitions - Boost 1.53 and gcc 4.8 incompatibility?
by Nate Finch 09 Apr '14

09 Apr '14

I recently upgraded to Ubuntu Trusty Tehr, and now the C++ project I'm working on won't build. It looks like the stdlib and Boost aren't working nicely together for some reason. A bunch of typedefs are conflicting between the two, below is one of the errors, where intmax_t is getting defined in two places. I'm not sure what changed, but I now have gcc (Ubuntu/Linaro 4.8.2-14ubuntu2) 4.8.2 and boost Version: 1.53.0.0ubuntu2 Here's an example error message: /usr/include/inttypes.h:290:8: error: reference to ‘intmax_t’ is ambiguous extern intmax_t imaxabs (intmax_t __n) __THROW __attribute__ ((__const__)); ^ In file included from /usr/lib/gcc/x86_64-linux-gnu/4.8/include/stdint.h:9:0, from /usr/include/inttypes.h:27, from src/uint256.h:11, from src/key.h:12, from src/crypter.h:8, from src/keystore.h:8, from src/script.h:14, from src/script.cpp:11: /usr/include/stdint.h:134:19: note: candidates are: typedef long int intmax_t typedef long int intmax_t; ^ In file included from /usr/include/boost/math_fwd.hpp:12:0, from /usr/include/boost/math/common_factor_ct.hpp:13, from /usr/include/boost/variant/variant.hpp:44, from /usr/include/boost/variant.hpp:17, from src/script.h:12, from src/script.cpp:11: /usr/include/boost/cstdint.hpp:306:50: note: typedef boost::long_long_type boost::intmax_t typedef ::boost::long_long_type intmax_t; Any help would be much appreciated. I'm fine with downgrading something, I'm just not sure what to downgrade.... or if there's an actual fix, that's cool too. -- View this message in context: http://boost.2283326.n4.nabble.com/conflicting-intmax-t-definitions-Boost-1… Sent from the Boost - Users mailing list archive at Nabble.com.

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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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[wave] fail to parse variadics macro
by gag maker 03 Apr '14

03 Apr '14

Hi, I'm using wave library from boost 1.53.0. Library compiled with default settings, meaning BOOST_WAVE_SUPPORT_VARIADICS_PLACEMARKERS is set to 1 in wave_config.cpp Wave driver is also compiled to support variadics. However, when I try to feed translation unit to wave driver it reports following error: .../compiler.h:32:1: error: ill formed preprocessor directive: #define __builtin_warning(x, y...) (1) And btw, wave driver was called with --variadics option What went wrong here? Thank you, --Alex

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boost asio synchronous vs asynchronous operations performance
by Donald Alan 31 Mar '14

31 Mar '14

Hi, I'm trying to compare the performance of boost::asio asynchronous vs synchronous IO operations for a single client. Below, I've sample synchronous and asynchronous server applications, which send 25 byte message to the client in a loop continuously. On the client side, I'm checking at what rate it is able to receive the messages. The sample setup is pretty simple. In synchronous server case, it spawns a new thread per client connection and the thread keeps sending the 25-byte message in a loop. In asynchronous server case as well it spawns a new thread per client connection and the thread keeps sending the 25-byte message in a loop, using asynchronous write (main thread is the one which calls ioservice.run()). For the performance testing I'm using only one client. *Synchronous server code* #include <iostream> #include <boost/bind.hpp> #include <boost/shared_ptr.hpp> #include <boost/enable_shared_from_this.hpp> #include <boost/asio.hpp> #include <boost/thread.hpp> using boost::asio::ip::tcp; class tcp_connection : public boost::enable_shared_from_this<tcp_connection> { public: typedef boost::shared_ptr<tcp_connection> pointer; static pointer create(boost::asio::io_service& io_service) { return pointer(new tcp_connection(io_service)); } tcp::socket& socket() { return socket_; } void start() { for (;;) { try { ssize_t len = boost::asio::write(socket_, boost::asio::buffer(message_)); if (len != message_.length()) { std::cerr<<"Unable to write all the bytes"<<std::endl; break; } if (len == -1) { std::cerr<<"Remote end closed the connection"<<std::endl; break; } } catch (std::exception& e) { std::cerr<<"Error while sending data"<<std::endl; break; } } } private: tcp_connection(boost::asio::io_service& io_service) : socket_(io_service), message_(25, 'A') { } tcp::socket socket_; std::string message_; }; class tcp_server { public: tcp_server(boost::asio::io_service& io_service) : acceptor_(io_service, tcp::endpoint(tcp::v4(), 1234)) { start_accept(); } private: void start_accept() { for (;;) { tcp_connection::pointer new_connection = tcp_connection::create(acceptor_.get_io_service()); acceptor_.accept(new_connection->socket()); boost::thread(boost::bind(&tcp_connection::start, new_connection)); } } tcp::acceptor acceptor_; }; int main() { try { boost::asio::io_service io_service; tcp_server server(io_service); } catch (std::exception& e) { std::cerr << e.what() << std::endl; } return 0; } *ASynchronous server code:* #include <iostream> #include <string> #include <boost/bind.hpp> #include <boost/shared_ptr.hpp> #include <boost/enable_shared_from_this.hpp> #include <boost/asio.hpp> #include <boost/thread.hpp> using boost::asio::ip::tcp; class tcp_connection : public boost::enable_shared_from_this<tcp_connection> { public: typedef boost::shared_ptr<tcp_connection> pointer; static pointer create(boost::asio::io_service& io_service) { return pointer(new tcp_connection(io_service)); } tcp::socket& socket() { return socket_; } void start() { while (socket_.is_open()) { boost::asio::async_write(socket_, boost::asio::buffer(message_), boost::bind(&tcp_connection::handle_write, shared_from_this(), boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); } } private: tcp_connection(boost::asio::io_service& io_service) : socket_(io_service), message_(25, 'A') { } void handle_write(const boost::system::error_code& error, size_t bytes_transferred) { if (error) { if (socket_.is_open()) { std::cout<<"Error while sending data asynchronously"<<std::endl; socket_.close(); } } } tcp::socket socket_; std::string message_; }; class tcp_server { public: tcp_server(boost::asio::io_service& io_service) : acceptor_(io_service, tcp::endpoint(tcp::v4(), 1234)) { start_accept(); } private: void start_accept() { tcp_connection::pointer new_connection = tcp_connection::create(acceptor_.get_io_service()); acceptor_.async_accept(new_connection->socket(), boost::bind(&tcp_server::handle_accept, this, new_connection, boost::asio::placeholders::error)); } void handle_accept(tcp_connection::pointer new_connection, const boost::system::error_code& error) { if (!error) { boost::thread(boost::bind(&tcp_connection::start, new_connection)); } start_accept(); } tcp::acceptor acceptor_; }; int main() { try { boost::asio::io_service io_service; tcp_server server(io_service); io_service.run(); } catch (std::exception& e) { std::cerr << e.what() << std::endl; } return 0; } *Client code* #include <iostream> #include <boost/asio.hpp> #include <boost/array.hpp> int main(int argc, char* argv[]) { if (argc != 3) { std::cerr<<"Usage: client <server-host> <server-port>"<<std::endl; return 1; } boost::asio::io_service io_service; boost::asio::ip::tcp::resolver resolver(io_service); boost::asio::ip::tcp::resolver::query query(argv[1], argv[2]); boost::asio::ip::tcp::resolver::iterator it = resolver.resolve(query); boost::asio::ip::tcp::resolver::iterator end; boost::asio::ip::tcp::socket socket(io_service); boost::asio::connect(socket, it); // Statscollector to periodically print received messages stats // sample::myboost::StatsCollector stats_collector(5); // sample::myboost::StatsCollectorScheduler statsScheduler(stats_collector); // statsScheduler.start(); for (;;) { boost::array<char, 25> buf; boost::system::error_code error; size_t len = socket.read_some(boost::asio::buffer(buf), error); // size_t len = boost::asio::read(socket, boost::asio::buffer(buf)); if (len != buf.size()) { std::cerr<<"Length is not "<< buf.size() << " but "<<len<<std::endl; } // stats_collector.incr_msgs_received(); } } <b>Question:* When the client is running against synchronous server it is able to receive around 700K msgs/sec but when it is running against asynchronous server the performance is dropped to around 100K-120K msgs/sec. I know that one should use asynchronous IO for scalability when we have more number of clients and in the above case as I'm using only a single client, the obvious advantage of asynchronous IO is not evident. But the question is, is asynchronous IO expected to effect the performance so badly for a single client case or am I missing some obvious best practices to follow with asynchronous IO? Is the significant drop in the performance is because of the thread switch between ioservice thread (which is main thread in the above case) and connection thread? *Setup:* I'm using BOOST 1.47 on Linux machine. -- View this message in context: http://boost.2283326.n4.nabble.com/boost-asio-synchronous-vs-asynchronous-o… Sent from the Boost - Users mailing list archive at Nabble.com.

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[fusion 1.55.0] fusion::map avoid copy construction for elements
by Frank Bergemann 30 Mar '14

30 Mar '14

3 2

[Thread] why isn't it possible to acquire 2 different upgrade_lock from 2 different threads?
by Elad Moshe 30 Mar '14

30 Mar '14

Hi, this is my first post here so please bare with me :) . I recently used upgrade_lock to try access a shared resource from 2 different threads. I noticed that once the first thread acquired its upgrade_lock the second thread was blacked until the first thread unlock it. can someone please explain me the logic behind this behavior? isn't an upgrade lock just a shared_lock that can be upgraded to unique_lock? why not let both threads acquire it just like shared_lock until, and if, they decide to upgrade it to unique_lock? Thanks a lot, Elad.

4 6

cross compiling boost python (64->32bits)
by Stéphane ANCELOT 30 Mar '14

30 Mar '14

Hi, I need to compile boost python from my linux system. the host system is a 64bits , and the target a 32 bit one. when I try using it on the target system, I have this message, ImportError: ./libboost_python.so.1.55.0: undefined symbol: Py_InitModule4_64 So, I suppose it is not compiled for 32bits system . I have tried many things, what is the right way to compile a 32 bits boost python lib, from a linux 64 bits system ? Regards, Steph

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cygwin 64 boost install
by jfrm.maurel＠gmail.com 29 Mar '14

29 Mar '14

Hi, Trying to install boost 1_54 (I had the same problem with 1.55) on my laptop Windows 7 (64bits RAM 6 Go), I have following failure (details in attached file): common.mkdir bin.v2/libs/context/build common.mkdir bin.v2/libs/context/build/gcc-4.8.2 common.mkdir bin.v2/libs/context/build/gcc-4.8.2/release common.mkdir bin.v2/libs/context/build/gcc-4.8.2/release/address-model-64 common.mkdir bin.v2/libs/context/build/gcc-4.8.2/release/address-model-64/link-static common.mkdir bin.v2/libs/context/build/gcc-4.8.2/release/address-model-64/link-static/asm gcc.compile.asm bin.v2/libs/context/build/gcc-4.8.2/release/address-model-64/link-static/asm/make_x86_64_sysv_elf_gas.o libs/context/src/asm/make_x86_64_sysv_elf_gas.S: Messages de l'assembleur: libs/context/src/asm/make_x86_64_sysv_elf_gas.S:43: Avertissement: .type pseudo opérateur utilisé à l'extérieur de .def/.endef ignoré. libs/context/src/asm/make_x86_64_sysv_elf_gas.S:43: Erreur: rebut à la fin de la ligne, premier caractère non reconnu est « m » libs/context/src/asm/make_x86_64_sysv_elf_gas.S:73: Avertissement: .size pseudo opérateur utilisé à l'extérieur de .def/.endef ignoré. libs/context/src/asm/make_x86_64_sysv_elf_gas.S:73: Erreur: rebut à la fin de la ligne, premier caractère non reconnu est « m » "g++" -x assembler-with-cpp -O3 -finline-functions -Wno-inline -Wall -m64 -DBOOST_ALL_NO_LIB=1 -DNDEBUG -I"." -c -o "bin.v2/libs/context/build/gcc-4.8.2/release/address-model-64/link-static/asm/make_x86_64_sysv_elf_gas.o" "libs/context/src/asm/make_x86_64_sysv_elf_gas.S" ...failed gcc.compile.asm bin.v2/libs/context/build/gcc-4.8.2/release/address-model-64/link-static/asm/make_x86_64_sysv_elf_gas.o... gcc.compile.asm bin.v2/libs/context/build/gcc-4.8.2/release/address-model-64/link-static/asm/jump_x86_64_sysv_elf_gas.o The process I followed after fresh cygwin 64 install: tar --bzip2 -xf boost_1_54_0.tar.bz2 cd boost_1_54_0/ ./bootstrap.sh #./b2 -j8 --prefix=$PWD --libdir=$PWD/lib64 --layout=tagged link=static threading=multi,single install || echo FAILURE ./b2 --prefix=$PWD --libdir=$PWD/lib64 --layout=tagged link=static threading=single address-model=64 install >build.log Could you please tell me what I am doing wrong ? I have read https://groups.google.com/forum/#!msg/boost-devel-archive/vqK2MXdmUZ0/cvhmd… but don't know if this is related. Regards -- Jean-François MAUREL PIMECA http://www.pimeca.com

2 2

[BOOST Users] serialize a pointer
by Andy Sardina 29 Mar '14

29 Mar '14

Hello, I would like to just serialize a pointer value. I have understood that boost save the pointer value, and serialize the object it points. How can I do?

2 1

[serialization] serialization of an ifstream/ofstream class member
by Pablo Madoery 28 Mar '14

28 Mar '14

Hi. Do You know if there is a way to serialize an ifstream/ofstream class member. I have this class for example class Object { public: Object(); Object(string name); virtual ~Object(); string getName() const; private: string name_; ifstream file_; friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & name_; ar & file_; } }; when I try to serialize it throw compilation error : error: 'struct std::basic_ifstream<char>' has no member named 'serialize'. Is there a specific header i must include ?

3 3

[serialization] of nested stl containers
by Pablo Madoery 27 Mar '14

27 Mar '14

I have the following code: #include <list> #include <utility> #include <vector> #include <string> #include <fstream> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/serialization/access.hpp> #include <boost/serialization/string.hpp> #include <boost/serialization/vector.hpp> #include <boost/serialization/utility.hpp> #include <boost/serialization/map.hpp> #include <boost/serialization/base_object.hpp> using namespace std; int main() { list< pair<string, string> > stlStr; pair<string, string> par1("aaa", "bbb"); stlStr.push_back(make_pair("key", par1)); std::ofstream ofs("filename"); { boost::archive::text_oarchive serial(ofs); serial << stlStr; } std::ifstream ifs("filename"); boost::archive::text_iarchive serial2(ifs); list<pair<string, string> > lst; serial2 >> lst; return 0; } that throw the following compilation error: error: 'class std::list<std::pair<std::basic_string<char>, std::basic_string<char> > >' has no member named 'serialize'. I'd like to know if I have to manually implement the serialization of this nested list. Because for example I haven't problems with maps that have inside a pair : map<string, pair<string, string> >. Thanks !

3 4

boost::future and when_all => compile error "call to deleted constructor"
by Tobias Oberstein 26 Mar '14

26 Mar '14

Hello, I am trying to use boost::future with continuations, in particular when_all/when_any. I am using Boost trunk from GitHub (since only that has when_all etc). This is what I want to compile: === #include <iostream> #define BOOST_THREAD_PROVIDES_FUTURE #define BOOST_THREAD_PROVIDES_FUTURE_CONTINUATION #define BOOST_THREAD_PROVIDES_FUTURE_WHEN_ALL_WHEN_ANY #include <boost/thread/future.hpp> using namespace boost; int main() { future<int> f1 = async([]() { return 1; }); future<int> f2 = async([]() { return 2; }); auto f3 = when_all(f1, f2); f3.then([](decltype(f3)) { std::cout << "done" << std::endl; }); f3.get(); } === https://gist.github.com/oberstet/9783359 This bails out with /usr/include/c++/v1/memory:1685:31: error: call to deleted constructor of 'boost::future<int>' https://gist.github.com/oberstet/9783364 Am I doing it wrong? Thanks! /Tobias

2 2

[msm] handle errors and no_transition
by Sam Fisher 25 Mar '14

25 Mar '14

Hi, I have root fsm which has a sub-fsm. In the sub-fsm there are some useful actions that can throw exceptions. For that case any fsm has its own exception handler that translates exception into a generic error event: template <typename Event, typename OtherFSM> void exception_caught(Event&, OtherFSM& fsm, std::exception& e) { fsm.process_event(error()); } I faced a strange problem: if an exception occurs, the sub successfully goes to Error state, the root has no_transition I use boost 1.55 and VS2013 there are transition tables: Sub: Error & Finish - exit points A_Exception action generates exception typedef ::boost::mpl::vector<Empty, AllOk> initial_state; struct /*sub*/ transition_table : public ::boost::mpl::vector < // Start Event Next Action Guard // +----------------+---------------+------------------+----------------------+--------------------------+ Row < Empty , none , Waiting , none , none >, Row < Waiting , process , Process , A_Exception , none >, Row < Process , none , Finish , none , none >, // +----------------+---------------+------------------+----------------------+--------------------------+ Row < AllOk , error , Error , none , none > // +----------------+---------------+------------------+----------------------+--------------------------+ > {}; Root: struct S { typedef SubFsm::exit_pt<SubFsm_::Error> Error; typedef SubFsm::exit_pt<SubFsm_::Finish> Finish; }; struct /*root*/ transition_table : public ::boost::mpl::vector < // Start Event Next Action Guard // +----------------+---------------+------------------+----------------------+--------------------------+ Row < Empty , init , Initial , none , none >, Row < Initial , sub , SubFsm , none , none >, // +----------------+---------------+------------------+----------------------+--------------------------+ Row < S::Error , error , Error , none , none >, Row < S::Finish , none , Initial , none , none > // +----------------+---------------+------------------+----------------------+--------------------------+ > {}; the control flow: Root root; root.start(); root.process_event(init()); root.process_event(sub()); root.process_event(process()); output log: =============> start Root_::InitEvent: Enter to Root_ state. Root_::InitEvent: Enter to Root_::Empty state. =============> init Exit from Root_::Empty state. init: Enter to Root_::Initial state. =============> sub Exit from Root_::Initial state. sub: Enter to Root_::SubFsm_ state. sub: Enter to SubFsm_::Empty state. sub: Enter to SubFsm_::AllOk state. Exit from SubFsm_::Empty state. front::none: Enter to SubFsm_::Waiting state. =============> process Exit from SubFsm_::Waiting state. SubFsm_::A_Exception() State machine produces an exception on event process Current state: SubFsm_::Waiting Message: A_Process exception Exit from SubFsm_::AllOk state. error: Enter to SubFsm_::Error state. No transition from state Root_::SubFsm_ on event process Exit from SubFsm_::Waiting state. Exit from SubFsm_::Error state. Exit from Root_::SubFsm_ state. error: Enter to Root_::Error state. A I understood, after exception comes, the "process" event now in kind of "unhandled" state. So it rises up to the root fsm that doesn't have any suitable transition How to make the root or sub to "forget" about unhandled event?

3 4