June 2012 - Boost-users - lists.preview.boost.org

mapped_region locks on multithread
by Mikhail Eremin 09 Jun '12

09 Jun '12

Hello, SETTING: - There is an application, written using Boost Template library, meant for QUICK processing of bulk text files (cca 50-100Gb each). - There is a huge, quick and expensive piece of hardware with HUGE amount of RAM and multiple CPU. - There is [theoretically] any possible UNIX-like OS, even Microsoft Windows (R) is considered. - Boost Thread Pool extension is used; previously memory mapped files through memory_segment have been used, now got rid of the entire Boost::interprocess. - There are NO explicit data items in the application's algorithm to be shared by threads, each has its own piece of input file, thus - there is NO explicit concurrency. PROBLEM: - Ensure fast processing without locks and threads sleeping. Currently the threads sleep on some internal mutex. We thought it's been boost::interprocess (specifically - mmap, wrapped by a mutex), but it apparently isn't so. SPECIFIC QUESTION: - How could we get rid of Boost locks? Mike

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[Intrusive][Interprocess] Using Intrusive Containers in Managed Shared Memory
by Hering Cheng 09 Jun '12

09 Jun '12

Hi, Is it possible to use Boost.Intrusive containers in managed shared memory? If so, are there examples that I can learn from? Thanks.

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define multi dimension array at run time
by Moataz Elmasry 08 Jun '12

08 Jun '12

Hello list I'm writing an n-dimensional histogram class and would like to use the boost multidimension array to store the elements of the histogram So the array is defined as a class member but is first initialized through the constructor, but according to boost example page its something like: typedef boost::multi_array<double, 3> array_type; but I'd like: typedef boost::multi_array<std::vector<MyObject>, n> array_type; where n is given through the constructor Is this somehow possible? Regards Moataz

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C++Now! keynote videos are available
by Marshall Clow 08 Jun '12

08 Jun '12

Howard's was not recorded Daveed: http://www.youtube.com/watch?v=8SOCYQ033K8 Sean: http://www.youtube.com/watch?v=iGenpw2NeKQ The full list of videos is at: http://www.youtube.com/user/BoostCon (more will be added soon) -- Marshall Marshall Clow Idio Software <mailto:mclow.lists@gmail.com> A.D. 1517: Martin Luther nails his 95 Theses to the church door and is promptly moderated down to (-1, Flamebait). -- Yu Suzuki

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Building PDF with Open Source Solution
by Christian Henning 08 Jun '12

08 Jun '12

Hi there, This is slightly off topic. I have a question how pdf's are build within the boost build system. As far as I could figure it out the build system uses a proprietary solution called RenderX XEP or so. I'm wondering if there are open source solutions out there that could be used to generate boost's documentation as pdf files? Thanks, Christian

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[serialization] custom allocation/deletion
by Brian Budge 07 Jun '12

07 Jun '12

Hi all - Is there a way to use custom allocation while loading from an archive? I'm thinking like passing an allocator along with the archive during deserialization? Adding to this, is it possible to add a custom deleter to a shared_ptr during deserialization? I am thinking of using this with boost mpi, and if I send a shared_ptr over the wire with some kind of deleter, the same deleter object can't be used on the other side since it's in a different address space. Thanks, Brian

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signal_set_service.ipp(247) error SIG_ERR undeclared
by Christopher Pisz 07 Jun '12

07 Jun '12

signal_set_service.ipp(247) error SIG_ERR undeclared I am getting this error when trying to compile a precompiled header that includes boost\asio.hpp I am using boost version 1.49.0 This did not occur with 1.40.0 Any ideas?

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[pool] Questions about memory pool
by Junchao Zhang 07 Jun '12

07 Jun '12

Hello, I'm new to boost memory pool. I have two questions: 1) My program has multiple iterations. In each iteration, I need to allocate chunks(objects) from a pool. I don't need to allocate array of chunks. I don't free objects until the end of an iteration. Then what is the most efficient way to do that? I wrote the following code, but I'm not sure it is right. boost::pool<> p(sizeof(MyType)); for (...) { ... // many calls to p.malloc(); ... p.release_memory(); // Is it OK??? } Also, I was wondering, to improve locality, how to reuse the memory in the next iteration, instead of deallocating/allocating memory again and again. 2) How to inquiry a pool to know have many objects have been allocated from the pool? For example, if malloc() 2 times, free() 1 time, then the count is 1. Does boost pool have this interface? Thanks! -- Junchao Zhang

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[MSM] cannot use state machine level internal_transition_table within the state machine which has Completion (anonymous) transitions in its transition_table
by James Zhang 06 Jun '12

06 Jun '12

Hi, I'm trying to setup a MSM state machine, according to : https://groups.google.com/group/boost-list/browse_thread/thread/bd9854b58a3… I can setup a state machine level internal_transition_table to handle the state-independent events. but the build failed if the transition_table has Completion (anonymous) transitions. I did following test: 1. if I remove the internal_transition_table, the build succeed. 2. if I give an event to the Rows, then the build succeed tool Row < Initialized , none , Synchronized >, Row < Synchronized , none , WaitResponse , sendPoll >, could anybody give me some clues about this? thanks. following is the code: #include <iostream> // back-end #include <boost/msm/back/state_machine.hpp> //front-end #include <boost/msm/front/state_machine_def.hpp> #include <boost/msm/front/functor_row.hpp> //#include <boost/msm/front/euml/common.hpp> // for And_ operator //#include <boost/msm/front/euml/operator.hpp> using namespace std; namespace msm = boost::msm; using namespace msm::front; namespace mpl = boost::mpl; // for And_ operator //using namespace msm::front::euml; namespace { // events struct evt_empty {}; struct evt_response{}; // front-end: define the FSM structure struct mystatemachine_ : public msm::front::state_machine_def<mystatemachine_> { // The list of FSM states struct Initialized : public msm::front::state<> { // every (optional) entry/exit methods get the event passed. template <class Event,class FSM> void on_entry(Event const&,FSM& ) { std::cout << "entering: Initialized" << std::endl; } template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "leaving: Initialized" << std::endl;} }; struct Synchronized : public msm::front::state<> { // every (optional) entry/exit methods get the event passed. template <class Event,class FSM> void on_entry(Event const&,FSM& ) { std::cout << "entering: Synchronized" << std::endl; } template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "leaving: Synchronized" << std::endl;} }; struct WaitResponse : public msm::front::state<> { // every (optional) entry/exit methods get the event passed. template <class Event,class FSM> void on_entry(Event const&,FSM& ) { std::cout << "entering: WaitBSPResponse" << std::endl; } template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "leaving: WaitBSPResponse" << std::endl;} }; // the initial state of the sas SM. Must be defined typedef Initialized initial_state; // actions struct sendPoll { template <class EVT,class FSM,class SourceState,class TargetState> void operator()(EVT const& ,FSM& ,SourceState& ,TargetState& ) { cout << "send sync poll" << endl; } }; // Transition table for sas struct transition_table : mpl::vector< // Start Event Next Action Guard // +----------------------+--------------------+----------------------+---------------+--------------------+ Row < Initialized , none , Synchronized >, Row < Synchronized , none , WaitResponse , sendPoll >, Row < WaitResponse , evt_response , WaitResponse , sendPoll , none > // +----------------------+--------------------+----------------------+---------------+--------------------+ > {}; struct internal_guard { template <class EVT,class FSM,class SourceState,class TargetState> bool operator()(EVT const& evt ,FSM&fsm,SourceState& ,TargetState& ) { std::cout << "Empty::internal_transition_table guard " <<std::endl; return true; } }; struct internal_action { template <class EVT,class FSM,class SourceState,class TargetState> void operator()(EVT const& ,FSM& fsm,SourceState& ,TargetState& ) { std::cout << "Empty::internal_transition_table action\n" <<std::endl; } }; struct internal_transition_table : mpl::vector< // Start Event Next Action Guard Internal < evt_empty , internal_action ,internal_guard > // +---------+-------------+---------+---------------------+----------------------+ > {}; // Replaces the default no-transition response. template <class FSM,class Event> void no_transition(Event const& e, FSM&,int state) { std::cout << "no transition from state " << state << " on event " << typeid(e).name() << std::endl; } }; // Pick a back-end typedef msm::back::state_machine<mystatemachine_> MyStateMachine; // // Testing utilities. // static char const* const state_names[] = { "initialized", "synchronized", "waitBSPResponse" }; void pstate(MyStateMachine const& p) { std::cout << " -> " << state_names[p.current_state()[0]] << std::endl; } void test() { MyStateMachine sm; sm.start(); sm.process_event(evt_empty()); pstate(sm); } }

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1.50.0 beta 1 Beta release available
by Beman Dawes 06 Jun '12

06 Jun '12

Boost release 1.50.0 beta 1 is now available from SourceForge See http://sourceforge.net/projects/boost/files/ This release contains 4 new libraries (Algorithm, Functional/OverloadedFunction, LocalFunction, Utility/IdentityType) and numerous enhancements and bug fixes for existing libraries. For details of what's in the release, see http://beta.boost.org/users/history/version_1_50_0.html. Note that the links to files on this web page are for the final release - use the SourceForge link above to get the beta files. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

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