April 2015 - 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] Crashing Issue
by swati upadhyaya 04 Nov '15

04 Nov '15

hi I am using like this where RunningThreads_ is vector containing boost thread object pointer(handler).I am using interrupt() for the interruption of thread interruption_point() catching that interruption then joining.everytime its crashing in join() for me but for others who have the same configuration its working fine all of us has windos 8. For me also it was working last week but this week the same piece of code is crashing. :( RunningThreads_[i].handle->interrupt(); RunningThreads_[i].handle->join(); delete RunningThreads_[i].handle; On Thu, Feb 5, 2015 at 9:31 AM, swati upadhyaya <swatiupadhyaya(a)gmail.com> wrote: > RunningThreads_[i].handle->interrupt(); > LOG4CPLUS_INFO(root, "Thread Interrupted for " << > RunningThreads_[i].app_name << " successful"); > RunningThreads_[i].handle->join(); > LOG4CPLUS_INFO(root, "Waiting for thread to exit " << > RunningThreads_[i].app_name << " successful"); > delete RunningThreads_[i].handle; > LOG4CPLUS_INFO(root, "Thread handle for " << > RunningThreads_[i].app_name << " successfully deleted"); > //RunningThreads_.erase(i); > > On Wed, Feb 4, 2015 at 12:10 AM, Vicente J. Botet Escriba < > vicente.botet(a)wanadoo.fr> wrote: > >> Le 03/02/15 09:10, swati upadhyaya a écrit : >> >> In my code join() timed_joined() is crashing, I am using these API >> after interrupt(),Same piece of code is working for others but in my system >> its crashing, >> Is there some dependency problem I am using >> Boost version: 1.55.0 >> OS: Windows 8 >> IDE: Visual Studio 2010 >> >> Hi, >> >> it could help if you post the example and the backtrace. >> >> Which version/OS/compiler use others for which this works? >> >> Vicente >> >> _______________________________________________ >> Boost-users mailing list >> Boost-users(a)lists.boost.org >> http://lists.boost.org/mailman/listinfo.cgi/boost-users >> > >

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the stability of breadth_first_visit in BGL
by breadbread1984 14 Jul '15

14 Jul '15

I am wondering if breadth_first_visit can always get the same sequence of vertex no matter whether the graph is serialized and deserialized again. Thx

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Re: [Boost-users] [IPC Named Mutex]
by Lorenzo Trivelli 19 Jun '15

19 Jun '15

> >One thing you could try...in interprocess's win32_api.hpp, there is another implementation of get_last_bootup_time() which uses WMI instead of the event log (there were warnings in the source about WMI not supporting hibernation/clock changes correctly, so beware). If you define >BOOST_INTERPROCESS_BOOTSTAMP_IS_LASTBOOTUPTIME >it should use that other version...give that a try. (in visual studio Project Properties -> C/C++ -> Preprocessor -> Preprocessor Definitions: add a semi colon ';' then t Thanks Tom, I'll try to fallback to the "old" WMI version (which BTW worked in the 1.44 version I we used before) I'd also be glad to fix it by myself and so help boost developement, , but I do not completely understand the usage of the system boot time... If boost needs in some way a tmestamp to differentiate things, in my opinion there are plenty of them to use instead of the last boot time. Obviously it has been done for a reason, but I cannot understand why :-D Best regards Lorenzo

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Some strange boost headers errors
by alfonso santimone 15 May '15

15 May '15

Hi guys, i'm a boost newbie. I've got to include boost libraries in the include path of a VisualStudio 2012 project. When i try to compile i have all these errors. Every errors is related to missing headers ( boost ones and even standard Win ones ) and to synthax errors depending on missing headers i guess. Do someone have any idea on what's wrong here? I just post here a few lines of errors, but the other ones are all of the same kind Error 1 error C2061: syntax error : identifier 'boost' C:\boost_1_57_0\boost\core\ checked_delete.hpp 24 1 csound~ Error 2 error C2059: syntax error : ';' C:\boost_1_57_0\boost\core\checked_delete.hpp 24 1 csound~ Error 3 error C2449: found '{' at file scope (missing function header?) C:\boost_1_57_0\boost\core\checked_delete.hpp 25 1 csound~ Error 4 error C2059: syntax error : '}' C:\boost_1_57_0\boost\core\checked_delete.hpp 67 1 csound~ Error 5 error C2054: expected '(' to follow 'using' C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\include\cstddef 19 1 csound~ Error 6 error C2061: syntax error : identifier 'using' C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\include\cstddef 19 1 csound~ Error 7 error C2061: syntax error : identifier 'boost' C:\boost_1_57_0\boost\smart_ptr\detail\sp_nullptr_t.hpp 23 1 csound~ Error 8 error C2059: syntax error : ';' C:\boost_1_57_0\boost\smart_ptr\detail\sp_nullptr_t.hpp 23 1 csound~ Error 9 error C2449: found '{' at file scope (missing function header?) C:\boost_1_57_0\boost\smart_ptr\detail\sp_nullptr_t.hpp 24 1 csound~ Error 10 error C2059: syntax error : '}' C:\boost_1_57_0\boost\smart_ptr\detail\sp_nullptr_t.hpp 41 1 csound~ Error 11 error C2054: expected '(' to follow 'using' C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\include\cstdlib 19 1 csound~ Error 12 error C2061: syntax error : identifier 'using' C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\include\cstdlib 19 1 csound~ Error 13 error C2061: syntax error : identifier 'abort' C:\Program Files (x86)\Microsoft Visual Studio many thanks in advance bests alfonso www.elgallorojorecords.com soundcloud.com/alfonsosantimone www.facebook.com/alfonsosantimone

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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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[serialization] std::shared_ptr with Boost >= 1.53
by Rüdiger Berlich 04 May '15

04 May '15

Hi there, I need to support various versions of Boost, but am in the process of porting our entire code base to C++11. This involves replacing those constructs of Boost that are now in the standard with their C++11-counterparts. A prime example is std::shared_ptr. However, most of our code needs to be serializable. I know that serialization of std::shared_ptr is possible with Boost 1.58. But 1.53 (the oldest version I need to support) cannot serialize std::shared_ptr . Is there any reason not to include the 1.58-Version of #include <boost/serialization/shared_ptr.hpp> instead of the older version, if I detect a Boost-version < 1.58 ? Thanks and Best Regards, Beet

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Boost.Cgi Status
by Michael Ainsworth 01 May '15

01 May '15

What is the status of Boost.Cgi by Darren Garvey? It seems that the library hasn't been accepted and it's now 2015 - at least 7 years after last Boost Users mailing list post regarding its status. Michael

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[gsoc15] This year's GSoC students
by Niall Douglas 27 Apr '15

27 Apr '15

Dear Boost, It is our pleasure to announce this year's winning GSoC students and projects: 1. Damian Vicino Topic: Safe Float (boost::safe_numerics<float>) Mentor: Robert Ramey 2. Rajaditya Mukherjee Topic: Boost uBLAS EigenSolver Mentor: David Bellot 3. Anurag Ghosh Topic: Boost Document Library Mentor: Antony Polukhin 4. Nikhar Agrawal Topic: Boost.Fixed-Point Mentor: Paul A. Bristow 5. Benedek Thaler Topic: Enhanced vector and deque containers Mentor: Thorsten Ottosen 6. Louis Dionne Topic: Improved compile-time associative data structures for Hana Mentor: Joel Falcou 7. Jakub Szuppe Topic: Improving Boost.Compute Mentor: Kyle Lutz Congratulations to these students for passing an exceptionally tough contest this year, and our thanks to the above mentors for making themselves available. Finally, thank you Google for another year of funding and to those open source orgs who released duplicate students to us, we appreciate it! Niall and Boris --- Boost C++ Libraries Google Summer of Code 2015 admin https://svn.boost.org/trac/boost/wiki/SoC2015

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Re: [Boost-users] boost examples
by Max 27 Apr '15

27 Apr '15

----- Original Message ----- From: mloskot <mateusz(a)loskot.net> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] boost examples Date: 2015-04-24 18:01 mloskot wrote > On 23 April 2015 at 11:44, Trek < > trek830@ > > wrote: >> Is there a central link where all official boost examples are hosted? > > No. You may check http://theboostcpplibraries.com/ for unofficial ones. ----- -- Mateusz Loskot, http://mateusz.loskot.net Charter Member of OSGeo, http://osgeo.org Member of ACCU, http://accu.org The book, Beyond the C++ Standard Library, also used to be a very good starting point of my understanding the boost libraries. Max

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[Pyhton] (re)binding class instance in python object
by Tamas.Ruszkai＠leica-geosystems.com 27 Apr '15

27 Apr '15

Hi, I have a plain C++ class which I want to exposed to python. The pyhton object accesses the C++ class via smart pointer. class Sensor : public boost::enable_shared_from_this<Sensor> { public: Sensor(int port); ~Sensor() void Open(); void SendCommand(const std::string& command); void Close(); private: int _port; }; auto sensorClassTypeObject = boost::python::class_<Sensor, boost:: shared_ptr<Sensor>>("Sensor", boost::python::init<int>()) .def("Open", &Sensor::Open) .def("SendCommand", &Sensor::SendCommand) .def("Close", &Sensor::Close); The question is: if I already have one instance of the C++ class (in a dependency injection container) then how can I create in the C++ part an instance of the python wrapper so that it does not create a new instance of Sensor, but uses my existing Sensor instance? Then I would put this instance into one of the python modules (this part would be made in C++) inside the python interpreter to be able to access it via script. Something like that: shared_ptr<Sensor> sensorInstance = DIContainer.Resolve<Sensor>(); boost::object pythonInstance = sensorClassTypeObject(sensorInstance); pythonInterpreterWrapper.AddToModule("__main__", pythonInstance); Best Regards, Tamas

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[msm] Event does not get processed after exiting an interrupt state
by Chrisopher Vogl 27 Apr '15

27 Apr '15

Hi all! I got a state machine with 2 regions. The second region has two states ("Run" and "Interrupt"), one is an interrupt state. The region starts in the non interrupt state, just like in the MSM example "Orthogonal regions, terminate state, event deferring". The event called Ev_Resume leads to a transition from state Interrupt back to state Run. In on_entry() of Run I fire an event which never gets processed. Is at that time the FSM still interrupted, i.e. event processing still blocked? Christopher

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Re: [Boost-users] [boost] [test] boost.test owner unresponsive to persistent problems for multiple years
by Paul A. Bristow 24 Apr '15

24 Apr '15

> -----Original Message----- > From: Boost [mailto:boost-bounces@lists.boost.org] On Behalf Of Richard > Sent: 17 March 2015 17:20 > To: boost(a)lists.boost.org > Subject: Re: [boost] [test] boost.test owner unresponsive to persistent problems for multiple years > > Another quarter has gone by and another Boost release is prepared for beta and I see *no* changes to > Boost.Test listed in the release notes.> > So here we are, waiting another 3 months for *simple* changes to be reflected in this library while the > maintainer insists that the fixes are available, yet they continue not to be deployed into any shipping release. It is indeed really deplorable that we don't have Boost.Test updates in a release. Though in mitigation I note that we are really struggling to get out a GIT-driven release at all, (and some of the new troubles are with asynch-exceptions in Boost.Test. See this thread Re: [boost] Running b2 on develop needs asynch-exceptions=on.) However, Richard's hard work on improved docs have been refined and completed by Raffi Enficiaud. Many bug fixes are in the develop branch (including some very new and prompt bug fixes, for example https://svn.boost.org/trac/boost/ticket/11054) I also understand that the fear of Boost.Test updates causing trouble with other libraries, and worse with users test, is a cause for caution in a release version. So it would be really good if *lots more users could download and use the version in the Boost.Test develop branch* so we can get current user feedback. (My experience is good using this, and the test matrix is also good). You can download just Boost.Test either using GIT or as a zip from https://github.com/boostorg/test/tree/develop and substitute it for the contents of the current release modular-boost/libs/test folder (Don't forget to rebuild the Boost.Test library unless you only use the included version). If nothing else, you will find Raffi's shiny new Boostbook docs finally allow you to find what you want to know without frustration. I'd very much like to see this new docs version in the 1.58 documentation release (despite any new features not being in the code release). Paul --- Paul A. Bristow Prizet Farmhouse Kendal UK LA8 8AB +44 (0) 1539 561830

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[log] Possible to explicitly disable AVX2?
by Jason Roehm 24 Apr '15

24 Apr '15

I am building Boost.Log on a relatively new machine whose compiler and CPU both support the AVX2 instruction set. Boost.Log detects this at build time and configures its compiler flags accordingly to use the AVX2 instruction set. I'd like to use the resulting binaries, however, on older systems that do not have AVX2 support. Is it possible to explicitly disable this at build time? I didn't see any mention of it in the documentation, and my attempts to parse the Jamfile's intentions were not successful. Thank you. Jason

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[nowide] Cannot end input using ^Z/^D on Windows
by Yuan Yao 24 Apr '15

24 Apr '15

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boost examples
by Trek 24 Apr '15

24 Apr '15

Is there a central link where all official boost examples are hosted? thanks,

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Boost.Thread Continuation future with executor blocking in destructor
by Konrad Zemek 23 Apr '15

23 Apr '15

Hi, When creating a continuation future with future<>::then(), and the policy is boost::launch::async, the created future's destructor blocks, like a future created by boost::async, and probably for the same reasons (as outlined by the standardization committee in n3679). The same behavior is coded into continuation futures' destructor when using an executor. Why is it needed here? The situation with executor-run continuations is a little different, as even when the future is destroyed, the lifetime of running job is still bound to the executor. My use case: I've coded a network communication stack that returns to the caller a future<NetworkResponse>. I've previously used std::async(std::launch::deferred, ...) to transform the future's content before returning it to the caller (bytes -> protobuf -> internal object), and I consider such manipulation of a future value to be a very powerful feature. I've used std::launch::deferred to reduce the number of running threads, but the downside is that the client can't wait for the future value with a timeout. On the other side of the spectrum is std::launch::async, which would run a new thread - per pending communication - that would do little more than block. boost::future<>::then is a fantastic fit for my use case, as I can use my boost::asio::io_service as an executor and let my communication stack's threads do the work without having them block on future.get() to first retrieve the result. The caller can then call future<>::wait_for() to wait for the reply with a custom timeout. This being network communication, though, a reply message may never arrive - the corresponding promise will eventually be destroyed by the stack, but I can't have users block on the future's destructor until that happens, after they have already decided that the reply is no longer worth waiting for. Please advise if there's a workaround for this behavior that doesn't involve me distributing a custom version of Boost.Thread with my binaries? :) Konrad

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[asio] What are the enhancements for Asio in 1.58
by Aaron Levy 22 Apr '15

22 Apr '15

I am sorry if this has been already asked. Wanted to get a head start on Asio 1.58, having heard that it's a significantly enhanced library. -- Aaron Levy aaron.levy(a)yandex.com

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[multi_index] Announcing preview of ranked indices
by Joaquin M Lopez Munoz 22 Apr '15

22 Apr '15

Hi, It's been 11 years since first proposed, but here it is at last. I'm releasing a prereview of ranked indices for Boost.MultiIndex: struct person { int age; std::string name; }; typedef multi_index_container< person, indexed_by< ranked_non_unique<member<person,int,&person::age> >, ordered_non_unique<member<person,std::string,&person::name>>>> multi_t; multi_t m={{40,"Joe"},{25,"Jill"},{30,"Kurt"},{32,"Sue"}}; auto it=m.emplace(31,"Maggie").first; std::cout<<m.rank(it)<<" persons younger than "<<it->name<<"\n"; auto n=m.size()/2; std::cout<<n<<" persons are less than "<<m.nth(n)->age<<" years old\n"; Ranked indices add a bunch of extra rank-related capabilities to the interface of ordered indices. The rank of an element is its numerical position in the index. nth(i) returns an iterator to the element with rank i, whereas rank(it) is the inverse operation. Both execute in log(n) time. Additionally, the member functions find_rank lower_bound_rank upper_bound_rank equal_range_rank range_rank behave as their "_rank"-less counterparts except they return ranks rather than iterators. One drawback of ranked indices wrt ordered indices (other than their slower perfomance and higher memory consumption) is that deletion of elements is log(n) (in ordered indices it is constant time). Download lib preview: http://tinyurl.com/kemwk8q Tutorial: http://tinyurl.com/q36c9f7 Reference: http://tinyurl.com/pvoulgr For people interested in this, I'd appreciate if you could download the source, copy it on top of Boost 1.58 (1.57 should work as well), play a bit with the new feature and report your results. Also, opinions on naming are welcome. Target version for releasing is Boost 1.59, so we have plenty of time to discuss the design before it is final. Thank you, Joaquín M López Muñoz Telefónica

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Which is the effective way for data transfer for Interprocess shared memory ?
by Kalyan Chakravarthy Gudimella 22 Apr '15

22 Apr '15

Hi, I am currently evaluating boost interprocess library for using shared memory. I found two ways to transfer complex data structures. 1. Creating data structures directly in shared memory. E.g. http://www.boost.org/doc/libs/1_58_0/doc/html/interprocess/allocators_conta… class complex_data{ int id_; char_string char_string_; int_vector_vector int_vector_vector_; public: //Since void_allocator is convertible to any other allocator<T>, we can simplify //the initialization taking just one allocator for all inner containers. complex_data(int id, const char *name, const void_allocator &void_alloc) : id_(id), char_string_(name, void_alloc), int_vector_vector_(void_alloc) {} //Other members...}; 2. Serializing data into bufferstream and deserializing it. E.g.http://www.boost.org/doc/libs/1_58_0/doc/html/interprocess/streams.html My initial trial shows that streaming to bufferstream took 7 times more time than using direct shared structures. Can you please help me to choose the effective way between these two approaches? thanks, Kalyan

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[MPL][Config] Can no longer pre-generate headers for MPL-containers with more than 50 elements.
by Deniz Bahadir 22 Apr '15

22 Apr '15

Hello everyone, While playing around with the current Boost release-candidate (1.58.0-RC3) I noticed that pre-generating MPL-headers for MPL-containers with more than 50 Elements seems no longer possible. Up till at least Boost 1.55.0 I was able to pre-generate these MPL-headers using the python-scripts from Boost-source ([1]) with the help of a bash-script which I already described here [2]. Internally, these python-scripts seem to use GCC to generate these MPL-headers. They also seem to partially circumvent Boost.Config by using custom user.hpp files located in subdirectories of [3] and defining BOOST_NO_CONFIG and some other macros therein. However, this does not seem to please Boost.Config so that compiler-errors ([4]) occur. Defining the macro BOOST_CONFIG_ALLOW_DEPRECATED as [4] suggests seems not to help. It just silences the warnings but does not generate proper files. (It actually erases the content of almost all header-files in subdirectories of [5].) Does anyone know how to workaround or better fix this? Or does anyone know who to talk to, to get these problems fixed? Also, I would suggest, that documentation for these python-scripts are added to the documentation of Boost.MPL. Best regards, Deniz References: [1] ${BOOST_SOURCE}/libs/mpl/preprocessed/ [2] http://stackoverflow.com/a/20660264/3115457 [3] ${BOOST_SOURCE}/libs/mpl/preprocessed/include/ [4] #error "You are using a compiler which lacks features which are now a minimum requirement in order to use Boost, define BOOST_CONFIG_ALLOW_DEPRECATED if you want to continue at your own risk!!!" [5] ${BOOST_SOURCE}/boost/mpl/aux_/preprocessed/

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[SPAM] from: giridhar
by giridhar 22 Apr '15

22 Apr '15

Greetings boost http://findislamicservices.com/reduce.php?silver=aswydt7xv2r0enm3 giridhar Sent from my iPhone

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sliding window containing n seconds of data
by Lane 22 Apr '15

22 Apr '15

I'm looking for a way to examine an array of object structures for an adjustable window of n seconds. My application reads objects at a high rate (which I'll have to throttle), and I'd then like to put them onto an array. My thinking is to assign a timer on each object that is initialized to n seconds and once the timer expires, the object is removed from the array, but while it's on the array, I'll iterate over the objects looking for the info I need. I put this out on the boost list as I suspect boost has the mechanisms to handle this and someone could suggest a good way of going about it. Any help much appreciated.

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1.58.0 rc3 is now available
by Marshall Clow 22 Apr '15

22 Apr '15

Release candidate files for 1.58.0 are available at: http://boost.cowic.de/rc/ * Since rc1, the changes that were causing the serialization libraries to fail to build on MSVC have been reverted. * Since rc2, the documentation for bind, and mem_fun. No code changes. 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: MD5 (boost_1_58_0_rc3.7z) = f7255aeb692c1c38fe761c32fb0d3ecd MD5 (boost_1_58_0_rc3.tar.bz2) = b8839650e61e9c1c0a89f371dd475546 MD5 (boost_1_58_0_rc3.tar.gz) = 5a5d5614d9a07672e1ab2a250b5defc5 MD5 (boost_1_58_0_rc3.zip) = b0605a9323f1e960f7434dbbd95a7a5c Thanks! -- The release managers P.S. Release notes are here: http://www.boost.org/users/history/version_1_58_0.html

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Re: [Boost-users] [IPC Named Mutex]
by Lorenzo Trivelli 21 Apr '15

21 Apr '15

Hi Tom, I tried your solution and it worked, and I'm stil wondering about the rationale behind the bootup time usage ;-) I also submitted a bug ticket, #11194, but track took a very long time to create it and add the test case, and in the end I found that: 1) a bug with ticket !11195 was also created 2) the test case was attached four times :-( can anyone please clean it up as is is a quite ugly ? ;-) regards Lorenzo

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Re: [Boost-users] [Serialization / 1.58] wrong number of entries in std::vector<boost::tuple<double, double, double> >
by Rüdiger Berlich 21 Apr '15

21 Apr '15

Hi Robert, I have submitted trac item 11214 and attached the test case. The trac web interface somehow froze for me upon submission (Safari / MacOS), and I apparently have pressed the submit button more than once, trying to submit the track item. So it appears as if more than one ticket has been created (11215 - 11218), which I do not seem to be able to delete. Please ignore these -- apologies. Best Regards, Beet > > ouch! - make a trac item for this! > > Robert Ramey > > > > -- > View this message in context: http://boost.2283326.n4.nabble.com/Serialization-1-58-wrong-number-of-entri… > Sent from the Boost - Users mailing list archive at Nabble.com. > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users >

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Web doc 1.58 Categorized error
by Larry 20 Apr '15

20 Apr '15

I tried to look at the 1.58 doc on the website and clicking on Categorized gave me under the headings By Category Unknown category: Data structures Apparently missing something. “All”, “Standard Proposals” etc seem to work. Larry

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[Serialization / 1.58] wrong number of entries in std::vector<boost::tuple<double, double, double> >
by Rüdiger Berlich 20 Apr '15

20 Apr '15

Hi, I’ve just installed Boost 1.58 and ran into the following problem: I have a class with a std::vector<boost::tuple<double, double, double> >, that is supposed to always have at least one entry, but may have more. Hence, in the default constructor, I initialize the std::vector with one entry. The class is also serializable. Up until Boost 1.57, a de-serialized object always had the correct number of entries in the vector. As of 1.58, I am getting one entry too much, which probably means that Boost.Serialization simply attaches entries to the vector of a default-constructed class, but doesn’t clear it first. This happens in C++11-Mode, both on Ubuntu 14.10 (gcc 4.9.1) as well as on MacOS X Yosemite . It DOES NOT happen with a std::vector<double> . Below is a full test case that replicates the problem in a simplified environment. For Boost 1.57 the program returns: t_vec.size() = 1 t_vec2.size() = 1 For Boost 1.58 the answer is t_vec.size() = 1 t_vec2.size() = 2 Best Regards, Beet /******************************************************/ #include <boost/archive/xml_oarchive.hpp> #include <boost/archive/xml_iarchive.hpp> #include <boost/serialization/nvp.hpp> #include <boost/serialization/vector.hpp> #include <boost/tuple/tuple.hpp> #include <iostream> #include <vector> #include <sstream> namespace boost { namespace serialization { template<typename archive, typename T0, typename T1, typename T2> void serialize(archive & ar, boost::tuple<T0, T1, T2> & tpl, unsigned int) { using namespace boost; using boost::serialization::make_nvp; ar & make_nvp("tpl_0", boost::get<0>(tpl)) & make_nvp("tpl_1", boost::get<1>(tpl)) & make_nvp("tpl_2", boost::get<2>(tpl)); } } /* namespace serialization */ } /* namespace boost */ int main() { std::vector<boost::tuple<double, double, double> > t_vec, t_vec2(1); std::ostringstream oss; t_vec.push_back(boost::tuple<double, double, double>(1.,2.,3.)); std::cout << "t_vec.size() = " << t_vec.size() << std::endl; // save data to archive { boost::archive::xml_oarchive oa(oss); // write class instance to archive oa & BOOST_SERIALIZATION_NVP(t_vec); // archive and stream closed when destructors are called // Data is now in oss } // load data from archive { std::istringstream iss(oss.str()); boost::archive::xml_iarchive ia(iss); // read class state from archive ia & BOOST_SERIALIZATION_NVP(t_vec2); // archive and stream closed when destructors are called } std::cout << "t_vec2.size() = " << t_vec2.size() << std::endl; }

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Compile errors in pointer_traits.hpp after upgrade to 1_58_0
by James Walker 20 Apr '15

20 Apr '15

After switching from Boost 1_57_0 to 1_58_0, I get various compile errors in pointer_traits.hpp, where it uses the macro BOOST_INTRUSIVE_HAS_STATIC_MEMBER_FUNC_SIGNATURE: warning: declaration does not declare anything error: use of undeclared identifier 'check' error: 'U' does not refer to a value This is with Xcode 4.6.3 and the Apple LLVM 4.2 compiler.

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Boost Spirit Karma - convert character to hex representation
by Ernest Zaslavsky 20 Apr '15

20 Apr '15

There is karma::hex formatter and I need somehow to add zero padding to get “0a” instead of just “a”. in addition it would be lovely to have some king of control over hex letter case. It sounds like a policies for real or Boolean formatters but I didn’t find one for hex. Is it possible to achieve the above without policy? [Read More]<http://feeds.feedburner.com/~r/sizmek-blog/~6/1> [http://www.sizmek.com/Sizmek.png]<http://www.sizmek.com/>

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Re: [Boost-users] Boost 1.58.0 has been released
by Florent Guiliani 20 Apr '15

20 Apr '15

On 4/18/15 6:00 PM, boost-users-request(a)lists.boost.org wrote: > On Fri, Apr 17, 2015 at 8:59 PM, Tom Kent<lists(a)teeks99.com> wrote: >> > >> >On Fri, Apr 17, 2015 at 3:58 PM, Marshall Clow<mclow.lists(a)gmail.com> >> >wrote: >>> >> >>> >>Release 1.58.0 of the Boost C++ Libraries is now available. > You sure about that? > Did you forget to push the release tag on Github? https://github.com/boostorg/boost/releases The release tag boost-1.58.0 is missing on Github. -- Florent

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Compile error with boost::factory after upgrade to 1.58.0
by Bitar Fadi 18 Apr '15

18 Apr '15

Hi, I installed Boost 1.58.0 today, having been using 1.57.0 previously, and noticed that a part of my code that uses boost::factory doesn't compile anymore. Here's briefly what I'm doing, followed by the error message I'm getting: typedef boost::function<Apollo::ReportGenerator*(Apollo::ApolloBaseModel*)> reportFactory; struct reportListing { std::string displayName; reportFactory factory; reportListing(std::string name, reportFactory f) : displayName(name), factory(f) { } }; std::vector<reportListing> reportFactories; reportFactories.push_back(reportListing("Scenario Analyzer", boost::factory<Apollo::ScenarioAnalyzer*>())); // Apollo::ReportGenerator being the base class from which Apollo::ScenarioAnalyzer is derived ... The constructor for ScenarioAnalyzer is: ScenarioAnalyzer(Apollo::ApolloBaseModel* model) This fails to compile with the following error (on Windows 7 using Visual C++ 12): error C2664: 'Apollo::ScenarioAnalyzer *boost::factory<Pointer,void,factory_alloc_for_pointee_and_deleter>::operator ()(void) const' : cannot convert argument 1 from 'Apollo::ApolloBaseModel *' to 'Apollo::ApolloBaseModel *&' I'm just wondering if that is caused by an intentional change or not, because according to the change log to boost::factory no significant changes with implications to backward compatibility have been made. Also, I'm not sure I know how to get rid of this error. Thanks for the help! /Fadi ________________________________ Fadi Bitar Modeling and simulation specialist Energy Markets Telephone direct +46 (0)8 695 64 05 Mobile +46 725 40 64 05 fadi.bitar(a)sweco.se<mailto:fadi.bitar@sweco.se> Sweco Energuide AB Gjörwellsgatan 22 P.O. Box 34044 SE-100 26 Stockholm Telephone +46 8 695 60 00 www.sweco.se<http://www.sweco.se/> [cid:image001.jpg@01CECF3E.855DC4C0] Please consider the environment before printing this e-mail.

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Boost 1.58.0 has been released
by Marshall Clow 18 Apr '15

18 Apr '15

Release 1.58.0 of the Boost C++ Libraries is now available. These open-source libraries work well with the C++ Standard Library, and are usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use. This release contains two new libraries and numerous enhancements and bug fixes for existing libraries. New Libraries * Endian: Types and conversion functions for correct byte ordering and more regardless of processor endianness. * Sort: Includes spreadsort, a general-case hybrid radix sort that is faster than O(n*log(n)) For details, including download links, see http://www.boost.org/users/news/version_1.58.0 You can also download directly from SourceForge: http://sourceforge.net/projects/boost/files/boost/1.58.0/ To install this release on your system, see http://www.boost.org/doc/libs/release/more/getting_started/index.html Thanks, --The Boost release team Vladimir Prus Rene Rivera Marshall Clow Eric Niebler Daniel James Beman Dawes

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How to suppress warnings from boost headers
by avib369 . 17 Apr '15

17 Apr '15

Is there any way using boost to suppress warning messages issued from the boost headers ? Is there a way to replace -I with -isystem ? Ta, Avi

1 0

multiprecision -- eigen matrices using dynamically allocated variable-precision mpfr_float
by Daniel Brake 17 Apr '15

17 Apr '15

I'd like to use the variable-precision mpfr_float type offered by the Boost.Multiprecision library, with the templated Eigen linear algebra library. I observe that if I make an identity matrix created with dynamically-allocated variable-precision mpfr_floats, and multiply it against itself, every other row is populated with nan's. Here is some code: int main(){ int size = 9; typedef boost::multiprecision::mpfr_float_backend<0, boost::multiprecision::allocate_dynamic> mybackend; typedef boost::multiprecision::number<mybackend, boost::multiprecision::et_on> mynumtype; typedef Eigen::Matrix<mynumtype, Eigen::Dynamic, Eigen::Dynamic> mp_matrix; mp_matrix A = mp_matrix::Identity(size, size); mp_matrix B = A*A; std::cout << B << std::endl; return 0; } output: 1 0 0 0 0 0 0 0 0 nan nan nan nan nan nan nan nan nan 0 0 1 0 0 0 0 0 0 nan nan nan nan nan nan nan nan nan 0 0 0 0 1 0 0 0 0 nan nan nan nan nan nan nan nan nan 0 0 0 0 0 0 1 0 0 nan nan nan nan nan nan nan nan nan nan nan nan nan nan nan nan nan nan I have been able to pin it down to the allocate_dynamic switch; if I select allocate_stack, the product computes correctly; allocate_dynamic reliably generates nans. Fixed-precision numbers work just fine, and expression templates on/off make no difference. I'd like to use the dynamic allocation, as I expect to use thousands of digits at times. I am using clang++, with c++11, on OSX, Boost 1.57.0, Eigen 3.2.4. Same behaviour in 1.56 / 3.2.3. It seems like maybe an offset issue, but I just can't get there by myself. I've also played with defining the NumTraits in Eigen various ways, but nothing affects the nan behaviour. Does anyone have any ideas? Daniel Brake Postdoctoral Research Scholar University of Notre Dame

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[boost][thread] thread_local vs boost::thread_specific vs ::pthread_key_t
by chilabot＠gmail.com 16 Apr '15

16 Apr '15

I have a program that dlopens some libraries (all C++), that use TLS for a variable (which passed to all libraries). With the keyword 'thread_local' and with 'boost::thread_specific', the storage of the variable is different for every thread AND for every shared library. With 'pthread_key_t' it's only different for every thread, it behaves as expected. I guess 'boost::thread_specific' uses 'thread_local' and that's why it behaves like it. Why does 'thread_local' behave like this? $ clang --version Ubuntu clang version 3.5.0-4ubuntu2~trusty2 (tags/RELEASE_350/final) (based on LLVM 3.5.0) Target: x86_64-pc-linux-gnu Thread model: posix $ uname -a Linux robert-y510p 3.13.0-49-generic #81-Ubuntu SMP Tue Mar 24 19:29:48 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux ref http://stackoverflow.com/questions/29656089/ thread-local-vs-boostthread-specific-vs-pthread-key-t

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[IPC Named Mutex]
by Lorenzo Trivelli 16 Apr '15

16 Apr '15

Hi to everyone, I'm experiencing a strange behaviour of named mutex on a windows 2008 machine. symptoms: when the system event log is empty, creation of named mutex fails with a boost::interprocess::interprocess:exception with msg boost::interprocess_exception::library_error. Now some data: 1) Boost 1.57.0 + stlport 5.2 2) VS 2005 3) Target Environment: Win 2008/32 3) after a night of code digging I managed to crete a small sample which raises the exception: #include <boost/shared_ptr.hpp> #include <boost/interprocess/sync/named_mutex.hpp> #include <boost/interprocess/sync/scoped_lock.hpp> #include <iostream> typedef boost::shared_ptr<boost::interprocess::named_mutex> safe_ipc_mx; static safe_ipc_mx __mx; int main(void) { system("pause"); try { __mx = safe_ipc_mx(new boost::interprocess::named_mutex(boost::interprocess::open_or_create_t(),"JAEGER")); std::cout << std::endl << "Mutex created !" << std::endl; } catch(boost::interprocess::interprocess_exception const& e) { std::cout << std::endl << "Mutex creation error " << e.what() << " /" << e.get_error_code() << " /" << e.get_native_error(); } system("pause"); return 0; } as far as I digged, it seems that the trouble is in the winapi::get_last_bootup_time(stamp) call in shared_dir_helpers.hpp, but up to now I had not been able to reproduce it on a machine with all the debugging tools installed does anyone have a clue on what I am doing wrong ? thanks in advance Lorenzo

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Re: [Boost-users] Project linking problem with boost
by Max 16 Apr '15

16 Apr '15

----- Original Message ----- From: <Mark.Bartosik(a)thomsonreuters.com> To: <boost-users(a)lists.boost.org> Subject: Re: [Boost-users] Project linking problem with boost Date: 2015-04-15 22:59 Try one of the /VERBOSE options on the linker’s command line will get you this information, I cannot remember which is the most painless one though. From the command line: /VERBOSE[:{CLR|ICF|INCR|LIB|REF|SAFESEH|UNUSEDLIBS}] /VERBOSE:LIB You can find this under Properties, Linker, General, Show Progress You can also set directly Properties, Linker, Command Line As I recall just /VERBOSE:LIB should generate a lot of output about which library is pulled in (and hopefully by which other library). Just the /VERBOSE output generate a huge amount of output (minimize the window and open with text editor later or it will be a long wait). - Mark - ------------------------------------------------------ Dear Mark, Thank you very much for your information - I didn't know this technique before. The problem is, though the problem seemed to be related to the linking process, the message as in my previous email was emitted by VS2008 before the linking process begins. So for the time being, I cannot benefit from adding extra switches to the link command. Best regards,Max --------------------------------------------------- From: Boost-users [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Max Sent: Wednesday, April 15, 2015 5:49 AM To: boost-users Subject: [Boost-users] Project linking problem with boost Sent: Wednesday, April 15, 2015 5:49 AM To: boost-users Subject: [Boost-users] Project linking problem with boost Hello, The problem here relates to boost, but I'm aware it may of more general nature rather than boost specific. I had a weird problem with my project. It has a bunch of dependencies including many of the boost libraries. My platform is: Win7SP1 + VS2008SP1 + boost1.39.0. I have properly set the VC++ directories for both include and lib files pointing to the boost folder (1.39.0) and of course those for other dependencies. But I got the following message when I built the project: 1>Linking to GSL lib 1>Linking to lib file: CGAL-vc90-mt.lib 1>Linking to lib file: libboost_date_time-vc80-mt-1_34.lib 1>Linking to lib file: libboost_regex-vc80-mt-1_34.lib I don't know why VS was attempting to link to libs of boost 1.34.0 built with VC80 (I'm using VC 90 - VS2008) Could anybody please give me some hints about this problem or where the message like "Linking to lib file: ..." came from? Thanks. Best regards, Max _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Re: [Boost-users] Project linking problem with boost
by Max 16 Apr '15

16 Apr '15

----- Original Message ----- From: Lorenzo Trivelli <trivelli.lorenzo(a)konvergence.it> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] Project linking problem with boost Date: 2015-04-15 22:32 Sorry, it may sound a dumb question but are you sure that there are no 1.34 includes before the 1.39 or that there is no hardcoded 1.34 include in your code ? regards Lorenzo Dear Lorenzo, Thank you for your hints and sorry for not giving more details.I don't have the 1.34.0 version of boost on my machine and I have no hardcoded dependencies on it in my code. Best regards,Max

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[Build Boost] Failed gcc.archive
by Jan Krämer 16 Apr '15

16 Apr '15

Hi all, I am trying to build boost_1_57 on Windows7 with MinGW64 (tried gcc 4.9 and 4.9.2). Compiling works fine but gcc.archive fails with: gcc.archive bin.v2\libs\atomic\build\gcc\debug\address-model-64\link-static\threading-multi\libboost_atomic-gcc-mt-d-1_57.a '"C:\mingw-w64\mingw64\bin"' is not recognized as an internal or external command, operable program or batch file. '"C:\mingw-w64\mingw64\bin"' is not recognized as an internal or external command, operable program or batch file. It does that on every gcc.archive operation. I read that this can be caused when using a path with spaces inside, which is not the case here. I did not found any other information and I am stuck right now. Full console output can be found at: http://pastebin.com/bWP0WHAA used commands were: > bootstrap.bat mingw > b2 --prefix=C:/Boost toolset=gcc address-model=64 install --debug-configuration >> boost.log Thanks in advance, any help would be appreciated. Cheers, Jan

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Re: [Boost-users] boost vs std atomic sequential consistency semantics
by Isaac To 16 Apr '15

16 Apr '15

On Wed, Apr 15, 2015 at 4:34 PM, Olivier Tristan <o.tristan(a)uvi.net> wrote: Have you tried Boost LockFree ? > http://www.boost.org/doc/libs/1_55_0/doc/html/lockfree.html > which handle multiple producer/Multiple-consumer queue > I know about the lockfree library, I've read the book underlying it (the Art of Multiprocessor Programming), and think I've understood at least 80% of it. My problem is not multiple producer multiple consumer queue, so it doesn't work for me. In particular, although there are multiple log producers, there is no consumer. They log into a ring buffer, and normally nobody would care and the log entries get overwritten by new entries (I want to avoid having to wait when logging). When the reader wants to read, it simply dumps everything in the ring buffer, and won't change the status of the buffer (i.e., it doesn't "consume"). And I don't care if the reader found a few entries are busy being overwritten, it just has to know about that so as to avoid using the data (which leads to wrong output and could lead to crash). The problem is in fact a lot easier than any of the queues / stacks that is implemented by lockfree. I've also inspected the assembly generated by g++ over my code in x86-64, and I think it is okay (i.e., no reordering with non-atomic statement is done by the compiler -- together with the strong consistency guarantee under x86-64 the code should be okay I think). Of course, "okay for one version of a brand of compiler and library under one platform" does not mean my program is correct: a new version of the compiler / library could break it, which is my main worry. But I've got something more fundamental to ask: what the memory model really means, and what to do once we (inevitably) move away from Boost and join the C++1x/y/z family. It seems to me that the C++ standard provides something quite a bit weaker than what Boost promises, and I don't know how to get the Boost promise from the C++ standard. That's the other reason why I ask. > Le 15/04/2015 08:42, Isaac To a ?crit : > > > I'd like to write a C++ object where there are many logger threads > > logging to a large global (non-atomic) ring buffer, with an occasional > > reader thread which wants to read as much data in the buffer as > > possible. I ended up having a global atomic counter where loggers get > > locations to write to, and each logger increments the counter > > atomically before writing. The reader tries to read the buffer and > > per-logger local (atomic) variable to know whether particular buffer > > entries are busy being written by some logger, so as to avoid using them. > Regards, Isaac

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Re: [Boost-users] Possible to use with JNI?
by Lorenzo Trivelli 15 Apr '15

15 Apr '15

At 06:30 13/04/2015, you wrote: >Hi, I really need to use Java with this library. Is it possible to use JNI on this library or do I need to convert this library to Java? I find the latter task is going to be really difficult so I hope that I can use JNI. > >Thank you for your help. Hi, AFAIK it is not easy to do that due to C++ name mangling and the absence of any ABI in C++ itself like C A possible but limited workaround should be to create a DLL with a C interface which uses the boost objects you need. Next, you can call it through JNI, but obviously you can pass only basic data types regardds Lorenzo

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[asio][bind] Access violation with placeholders used by static objects
by Olivier Sauvageau 15 Apr '15

15 Apr '15

Hello, I had an access violation issue using boost::asio::placeholders::error as parameter to boost::bind in a class that was used as type for a static class member object. I realized that the placeholders, both those in Asio and those in Bind (e.g., _1) are themselves static objects, and thus found out that my problem was due to the famous undefined order of initialization of static objects. I was able to fix my problem simply by encapsulating my static object in a function and making sure it's called only after main() has started. However, I'm still wondering, has this issue ever been discussed and any correction or alternative proposed? I couldn't find anything on the topic. On the other hand, I noticed that Asio's placeholders are initialized from functions, e.g. from <boost/asio/placeholders.hpp>: boost::arg<1>& error = boost::asio::placeholders::detail::placeholder<1>::get(); Using that function instead could be an alternative, but since it is not in the "public" namespace and is not in the library documentation, using it would not be a good idea for maintainability. Finally, is there any documentation stating the fact that placeholders such as boost::asio::placeholders::error and _1 are static? I can't find any in the Asio or Bind documentation, and I feel this is a limitation that should at least be documented. Thank you, -- Olivier Sauvageau

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Serialization of boost::shared_ptr - wrong ref. count?
by Josef Uher 15 Apr '15

15 Apr '15

Hi All, I am using serialisation of boost::shared_ptr objects. Saving/loading works fine, except that I found out that all shared_ptr objects have reference count (use_count) minimum of 2 even though they should have 1! Debugging into the boost’s code I found out that the ref. count is increased to value of 2 in “shared_ptr_helper.hpp”, line 181 where the pointer is stored inside map “m_o_sp”. This map however never gets deleted and hence the shared_ptr seems to be stored there for ever. Please, am I doing something wrong or is there a bug? How to fix this? The sample code I use is below. I would like to emphasise that I make sure the archives are deleted after being used. So it should release the resources. I am using Mac OS X 10.10.2, boost version 1.57.0 Thank you for help, Josef **************** #include <boost/iostreams/device/file_descriptor.hpp> #include <boost/iostreams/filtering_stream.hpp> #include <boost/archive/xml_iarchive.hpp> #include <boost/archive/xml_oarchive.hpp> #include <boost/serialization/shared_ptr.hpp> #include <boost/make_shared.hpp> class SOBJ { public: friend class boost::serialization::access; virtual void SerializationHelperFcn() {} SOBJ() { std::cout << "SOBJ Constructor" << std::endl; } virtual ~SOBJ() { std::cout << "SOBJ Destructor" << std::endl; } double value=0.; template<typename Archive> void serialize(Archive &ar, const unsigned int ver) { ar & boost::serialization::make_nvp("value", value); } }; void shared_ptr_serialization_test() { boost::shared_ptr<SOBJ> out=boost::make_shared<SOBJ>(); { boost::iostreams::filtering_ostream ofs; ofs.push(boost::iostreams::file_descriptor_sink("/Users/juhe/stest.xml")); boost::archive::xml_oarchive oa(ofs); oa << boost::serialization::make_nvp("tag", out); } boost::shared_ptr<SOBJ> in=nullptr; { boost::iostreams::filtering_istream ifs; ifs.push(boost::iostreams::file_descriptor_source("/Users/juhe/stest.xml")); boost::archive::xml_iarchive ia(ifs); ia >> boost::serialization::make_nvp("tag", in); } std::cout << "out.use_count()=" << out.use_count() << std::endl; std::cout << "in.use_count() =" << in.use_count() << std::endl; } ****************

2 3

Project linking problem with boost
by Max 15 Apr '15

15 Apr '15

Hello, The problem here relates to boost, but I'm aware it may of more general nature rather than boost specific. I had a weird problem with my project. It has a bunch of dependencies including many of the boost libraries. My platform is: Win7SP1 + VS2008SP1 + boost1.39.0. I have properly set the VC++ directories for both include and lib files pointing to the boost folder (1.39.0) and of course those for other dependencies. But I got the following message when I built the project: 1>Linking to GSL lib1>Linking to lib file: CGAL-vc90-mt.lib1>Linking to lib file: libboost_date_time-vc80-mt-1_34.lib1>Linking to lib file: libboost_regex-vc80-mt-1_34.lib I don't know why VS was attempting to link to libs of boost 1.34.0 built with VC80 (I'm using VC 90 - VS2008) Could anybody please give me some hints about this problem or where the message like "Linking to lib file: ..." came from? Thanks. Best regards, Max

3 2

Possible to use with JNI?
by Yolanda Septiana 15 Apr '15

15 Apr '15

Hi, I really need to use Java with this library. Is it possible to use JNI on this library or do I need to convert this library to Java? I find the latter task is going to be really difficult so I hope that I can use JNI. Thank you for your help.

2 2

boost vs std atomic sequential consistency semantics
by Isaac To 15 Apr '15

15 Apr '15

I've asked the question in stack overflow, but no luck there. I hope I will see some light here. I'd like to write a C++ object where there are many logger threads logging to a large global (non-atomic) ring buffer, with an occasional reader thread which wants to read as much data in the buffer as possible. I ended up having a global atomic counter where loggers get locations to write to, and each logger increments the counter atomically before writing. The reader tries to read the buffer and per-logger local (atomic) variable to know whether particular buffer entries are busy being written by some logger, so as to avoid using them. So I have to do synchronization between a pure reader thread and many writer threads. I sense that the problem can be solved without using locks, and I can rely on "happens after" relation to determine whether my program is correct. I've tried relaxed atomic operation, but it won't work: atomic variable stores are releases and loads are acquires, and the guarantee is that some acquire (and its subsequent work) always "happens after" some release (and its preceding work). That means there is no way for the reader thread (doing no store at all) to guarantee that something "happens after" the time it reads the buffer, which means I don't know whether some logger has overwritten part of the buffer when the thread is reading it. So I turned to sequential consistency. For me, "atomic" means Boost.Atomic, which notion of sequential consistency has a "pattern" documented <http://www.boost.org/doc/libs/1_57_0/doc/html/atomic/thread_coordination.ht…> : The third pattern for coordinating threads via Boost.Atomic uses seq_cst for coordination: If ... 1. thread1 performs an operation A, 2. thread1 subsequently performs any operation with seq_cst, 3. thread1 subsequently performs an operation B, 4. thread2 performs an operation C, 5. thread2 subsequently performs any operation with seq_cst, 6. thread2 subsequently performs an operation D, then either "A happens-before D" or "C happens-before B" holds. Note that the second and fifth lines say "any operation", without saying whether it modify anything, or what it operates on. This provides the guarantee that I wanted. All is happy until I watch the talk of Herb Sutter titled "atomic<> Weapons". What he implied is that seq_cst is just a acq_rel, with the additional guarantee of consistent atomic stores ordering. The suggestion that sequentially consistent atomic operations may be re-ordered with non-atomic operations only adds to my mystery. I turned to the cppreference.com <http://en.cppreference.com/w/cpp/atomic/memory_order>, which have similar descriptions. So my questions: 1. Does C++11 and Boost Atomic implement the same memory model? 2. If (1) is "yes", does it mean the "pattern" described by Boost is somehow implied by the C++11 memory model? How? Or does it mean the documentation of either Boost or C++11 in cppreference is wrong? 3. If (1) is "yes", but (2) is "Boost documentation is incorrect", is there any way to achieve the effect I want, namely to have guarantee that (the work subsequent to) some atomic store happens after (the work preceding) some atomic load? 4. If (1) is "no", is there any way to achieve the effect I want in C++11?

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Re: [Boost-users] Unable to build old project using boost
by Max 13 Apr '15

13 Apr '15

----- Original Message ----- From: John Maddock <jz.maddock(a)googlemail.com> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] Unable to build old project using boost Date: 2015-04-13 00:08 On 12/04/2015 15:24, Juan Ramírez wrote: It seems that boost wasn't compiled with VC++ 9. The macro BOOST_NO_RVALUE_REFERENCES is not defined, which means boost thinks the compiler supports rvalue references. Since the code is header only, how Boost was built is irrelevant - but there must be some mismatch between what Boost.Config is doing and what type_traits expects. The only thing I can think of that would cause that are either: * A really really old version of Boost.Config with a newer version of type_traits - not sure how you would manage that though, or... * You have a custom config (in boost/config/user.hpp) which is setup for a newer MSVC version. If all else fails, try with a fresh boost source tree, HTH, John. ------------------------------------------------------- Thank you very much John. I didn't changed anything of the boost installation whatsoever, except for the build itself, before that problem.I was using exactly the same thing as I did 2 yearly ago, when it worked. Now it works, for boost 1.39.0, 1.49.0 and 1.57.0. But I cannot think of anything that I did made the difference. Best regards,Max On Sat, Apr 11, 2015 at 10:33 AM, Edward Diener <eldiener(a)tropicsoft.com> wrote: On 4/11/2015 6:33 AM, Max wrote: Hi guys, This must be a trivial question, but I just couldn't sort it out. I'm compiling a old project which used to work fine. But now I received a bunch of errors (this is not a surprise because the project have a lot of other dependencies and I'm in the way of setting them up) with the first one as: c:\lib\boost_1_49_0\boost\type_traits\add_lvalue_reference.hpp(19) : error C2143: syntax error : missing ',' before '&&' I'm using Win 7 SP1 + VS 2008 with SP + boost 1.49.0 (I'm using this because I previous used this. If this works fine, I will consider migrating to the latest version) Thanks for any hints. If you are using an older version of Boost and it was working before and now it is not working, something must have changed. Try to determine what might have changed. You also need to show source code you are compiling when the error occurs. _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users -- Juan :wq _______________________________________________ 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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