July 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

3 2

[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.

3 4

[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

5 6

[Interprocess] Communication between x86 and x64 issue
by Toni Neubert 19 Feb '16

19 Feb '16

I want to communicate between different platforms using boost interprocess. I am using vc12 and boost 1.58 on windows 7. My code below is a very simple example, that should work. But it doesn't for communications between different platforms... If I create it in x64 and open in win32, the process stuck at a lock at function try_based_lock in boost/int/sync/detail/common_algorithms.hpp In the other way around: win32 create, x64 open: the process crashes at name_length in segment_manager_helper.hpp while trying to find the name in index (priv_generic_find in segment_manager). #include <iostream> #include <boost/interprocess/managed_shared_memory.hpp> int main() { namespace bip = boost::interprocess; // open in WIN32, create in x64 #ifdef _WIN32 bip::managed_shared_memory msm(bip::open_only, "TestIPC"); #elsif X64 bip::shared_memory_object::remove("TestIPC"); bip::managed_shared_memory msm(bip::create_only, "TestIPC", 4096); msm.construct<uint32_t>("Data")[1](10); #endif // Get Data and print it auto data = msm.find<uint32_t>("Data"); if (data.second == 1) { std::cout << *data.first << std::endl; } std::cin.ignore(); return 0; } Does anybody have experience in this? Thank you in advance!

3 2

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 >> > >

3 2

Query regarding interest in my submitting plf::colony to Boost
by Soul Studios 14 Aug '15

14 Aug '15

Hi all, I've had some expressions of support outside of the Boost community for submission of the plf::colony container and it's associated container plf::stack, mainly from the review judges for my cppcon submission on the same topic (topic didn't make it through to the finals but got a positive response). I'd like to guage reactions here to see whether it is worth spending the time necessary to port it to Boost, with all the associated reviews etc. plf::colony is a container for unordered data, where erasure and addition do not cause iterator/pointer invalidation, with superior performance characteristics to all std:: containers when either (a) Pointers and iterators which point to container elements must stay valid regardless of container additions and deletions and/or (b) Additions to or deletions from the container will be occurring in performance-critical code. Erasure performance in particular can be in advance of 6000x of vectors, while still being faster than lists, maps, deques etc for add and iteration. Full details and benchmarks across four compilers are here: http://www.plflib.org/colony.htm#benchmarks It has been thoroughly tested, including integrating it into the game engine I constructed last year as well as the usual unit tests. It supports both C++0x and C++11, and has been tested on the following compilers so far: Clang 3.4, GCC 4.6, 4.7, 4.8, 4.9 and 5.1 (both 32-bit and 64-bit), MS Visual C++ 2010 & 2013 (2015 supported but untested as yet). Internally a colony is a combination of a linked-list of increasingly-larger memory blocks combined with boolean erasure fields, combined with a custom memory location recycle stack. The most common comment I get is "that sounds kinda like a deque", so to save some time here are the differences (from the FAQ): "A double-ended queue requires a very different internal framework. It may or may not use a linked-list of memory blocks, dependent on the compiler, and has no comparable performance characteristics. Deque element erasure is very slow, similar to a vector, and it does not free unused memory blocks to the OS once they are empty, unlike a colony. In addition a deque invalidates references to subsequent container elements when erasing elements, which a colony does not. A colony never invalidates pointers/iterators to elements unless the element being referred to is erased." The rest of the faq is here and I would appreciate it if people read it before casting judgement: http://www.plflib.org/colony.htm I am aware that it will be a lot of work to port colony to Boost, so I will only undertake this if there is genuine interest. In addition, plf::stack - which colony must use internally - is a std::stack equivalent container but with much better performance characteristics, which can be used outside of plf::colony. Asides from the performance characteristics, colonies have the following positive and negative properties: Positive: Lack of pointer/iterator invalidation makes interrelating between collections of data easier, without the cache misses associated with vectors of pointers to dynamically-allocated objects. Negative: Due to the additional overhead, performance can be worse for scalar types. Thanks in advance- Matt B

5 13

[Boost.Iterator] transform_iterator equivalent for output iterators
by dariomt＠gmail.com 05 Aug '15

05 Aug '15

Here is my problem: for any given algorithm that writes its output into an output iterator, I'd like to apply a transformation *before* writing to the output iterator. e.g. inside the algorithm the output iterator is dereferenced and incremented to write each result, typically like this: *output++ = ith_result; I'd like to wrap the output iterator with a unary function func such that the effect is equivalent to: *output++ = func( ith_result ); I'm looking at the adaptors in Boost.Iterator but I cannot find a suitable one. Am I missing anything? Is there a better approach? Regards

7 8

[graph] Example parallel BGL
by Sensei 03 Aug '15

03 Aug '15

Dear all, I'd like to play with Parallel BGL (with MPI), and I'd like to see some example code. I've followed the Overview and the Adjacency List example, but I cannot compile my code. Right now, I'd like to create a graph, and then fill in with some nodes. Then, access the nodes belonging to a single process, but I wish I had an error there My error concerns the definition of the graph: No template named 'bsp_process_group' in namespace 'boost::parallel'; did you mean 'boost::process_group'? The code follows. What am I doing wrong here? I may have forgotten some header... Is there any distributed (complete) example code that I might read? Thanks & Cheers! #include <iostream> #include <string> #include <vector> #include <boost/mpi.hpp> #include <boost/graph/use_mpi.hpp> #include <boost/graph/distributed/mpi_process_group.hpp> #include <boost/graph/distributed/adjacency_list.hpp> int main(int argc, const char * argv[]) { boost::mpi::environment env; boost::mpi::communicator comm; typedef boost::adjacency_list<boost::vecS, boost::distributedS<boost::parallel::bsp_process_group, boost::vecS>, boost::directedS> graph; typedef boost::erdos_renyi_iterator<boost::minstd_rand, graph> generator; if (comm.rank() == 0) { boost::add_edge(1, 2); boost::add_edge(2, 2); boost::add_edge(2, 3); boost::add_edge(3, 4); boost::add_edge(4, 5); boost::add_edge(5, 1); // access ***only rank 0 nodes*** } return 0; }

2 2

Connected components not working Boost Graph library
by Choppin, Simon 03 Aug '15

03 Aug '15

Hello all, I hope you can help me, I'm trying to group 3D point data in clusters according to the distance between points. I.e. different groups (or components) are separated by a minimum threshold distance. To do this I am creating a boost graph (using the Boost Graph library), adding vertices (with 3D point information) and adding edges between nodes of the graph that are within my threshold distance. However, when I find the connected components on the resulting graph I'm getting an incorrect answer. The vertices of the graph are not grouped correctly. I am comparing my results with a Matlab script (and their proprietary programs) which correctly separates the points. I have a stackoverflow post with more detail (and no answers) http://stackoverflow.com/questions/27001402/connected-components-boost-c. If you are able to help in any way I'd be very appreciative. I really don't want to use compiled Matlab for this solution. Thanks Simon Choppin

3 9

Details of boost parallel graph implementation
by Mayank Bakshi 03 Aug '15

03 Aug '15

3 5

Structure size when compiling with and without -std=c++11
by Miloslav Marik 03 Aug '15

03 Aug '15

Hi, I would like to share my experience with boost when combining with c++11. I hope it might help someone. Suppose a simple program: #include <boost/asio.hpp> #include <iostream> using boost::asio::detail::atomic_count; struct Test { // Whether the task has been interrupted. bool task_interrupted_; // The count of unfinished work. atomic_count outstanding_work_; }; int main () { std::cout << "Size is " << sizeof(Test) << std::endl; return 0; } And here is the story: $ /opt/gcc-4.8.4/bin/g++ -std=c++11 -I /opt/boost-1.58.0/include/ -L /opt/boost-1.58.0/lib -lboost_system b.cpp $ ./a.out Size is 16 $ /opt/gcc-4.8.4/bin/g++ -I /opt/boost-1.58.0/include/ -L /opt/boost-1.58.0/lib -lboost_system b.cpp $ ./a.out Size is 8 It means that c++11 program cannot be linked with boost libraries compiled without "-std=c++11" option. It was asio in my case and the program was linked with libboost_log.so.1.58.0. I would really appreciate a short warning somewhere at "Getting Started on Unix Variants" page. It may safe someone a few hours of life. Best Regards, Slavek

3 2

Boost 1_59_0_b1_rc1 is available for testing
by Marshall Clow 02 Aug '15

02 Aug '15

Release candidate files for 1.59.0 beta 1 are available at http://boost.cowic.de/rc/ As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. This helps ensure the candidates build OK before we push them out to SourceForge. The files (and associated md5s) are: MD5 (boost_1_59_0_b1_rc1.7z) = f54a97e5ee7f8e3d04cd9af8396e30f9 MD5 (boost_1_59_0_b1_rc1.tar.bz2) = 9804305aae0c9de9f8cfc02e3de75167 MD5 (boost_1_59_0_b1_rc1.tar.gz) = e584770bd76885c123a0426d24466fe2 MD5 (boost_1_59_0_b1_rc1.zip) = ee34f223aa789a6b3f727cb9480651ed Thanks! -- The release managers

12 17

Need sample for CMakelist.txt with BOOST.test
by Abhay Mhatre 01 Aug '15

01 Aug '15

Hi, I am newbie, and struggling with testing project that is build in CMakeList.txt for using Boost.Test. project builds successfully and runs too, only problem is when unit test fails BOOST_REQUIRE exits without printing fatal exception message on console. It also doesn't show next failure. I tired compiling same library with g++ command and everything works as expected. however with CMakeList project there is no output I tried setting explicit boost::unit_test::unit_test_log_t::instance().set_threshold_level(boost::unit_test::log_all_errors) also tried with setting # define BOOST_TEST_LOG_LEVEL all but there is no output except fatal error on console. also it doesn't show fatal error for multiple tests/ Can some one please suggest some way to investigate this further/ provide sample CMakeList.txt file that I can compare and see if I am missing anything thanks in advance, Abhay

4 4

Map runtime value to type
by dariomt＠gmail.com 31 Jul '15

31 Jul '15

Hi all, Say I have a compile-time map of <value,type> pairs, and I need to access the correct element given a value at runtime and do something with that type. That something would be the same for any of the mapped types (e.g. calling an overloaded function that would then do the right thing depending on the type). The value would typically be an enum. Is there anything in the Boost libraries to help with this? If I used C++11, would there be a simple solution to this? Regards PS: I cannot use Boost.Variant

6 6

Re: [Boost-users] output boost graph parallel issue
by Mayank Bakshi 31 Jul '15

31 Jul '15

1 0

output boost graph parallel issue
by Mayank Bakshi 31 Jul '15

31 Jul '15

1 0

[Asio] [Boost.ASIO] async_read cannot read full data from client
by Sarvagya Pant 30 Jul '15

30 Jul '15

** I have a server created using Boost.ASIO (thanks to sehe from Stackoverflow). The server is supposed to received message from client, parse it as json and correspondingly send the message back to client. To make life easier, i have considered very simple cases: (i) Client can send {"hello":"client"}, server should send response {"hello":"server"} (ii) Client can send {"message" : "Some Message"}, server should send {"response" : "OK"} The server runs, accepts data from client but cannot call the handler of async_read. The doc states that The asynchronous operation will continue until one of the following conditions is true: 1. The supplied buffers are full. That is, the bytes transferred is equal to the sum of the buffer sizes. 2. An error occurred. I think in my case the buffer is not full, thus the handler function is not getting called. How should I change my code so that server can read the message sent by client, process it and send back correct response.? PS: If the code is not attached, http://pastebin.com/pi192t6i is the link to file. *-- Sarvagya PantKathmandu, Nepal+9779803468257*

2 4

how to know which xml_iarchive is parsing
by breadbread1984 30 Jul '15

30 Jul '15

my program serializing and deserializing an object has some problem. I am debugging it. I found it was so hard to debug the code without knowing which line the xml_iarchive is parsing. Is there any way to know which line the xml_iarchive is working on? Thx!

1 0

unsupported version problem of serialization of graph
by breadbread1984 30 Jul '15

30 Jul '15

I am using boost graph library. I can serialize the graph successfully. But when deserialized a graph from the file, an unsupported version exception was throwed out. I created a minimum runnable example and posted it [here] (http://www.rapidshare.com.cn/Bq95n2v) The serialized graph file is enclosed as well. The file is generated with the same version of graph library. Could anyone help me to find the problem? thx!

2 1

problem of deserializing from a xml file
by breadbread1984 30 Jul '15

30 Jul '15

I am having problem deserializing from a file of a serialized object. An exception of input stream error always occurs. The class of the object is pasted [here] (http://pastebin.com/6XEBybWV) The xml file is pasted [here] (http://pastebin.com/e2Ka2kVH) I tried debugging the program. The top few frames of the back trace of the exception is as follows #0 0x00007f8f9be4c267 in __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:55 #1 0x00007f8f9be4deca in __GI_abort () at abort.c:89 #2 0x00007f8f9c76006d in __gnu_cxx::__verbose_terminate_handler() () from /usr/lib/x86_64-linux- gnu/libstdc++.so.6 #3 0x00007f8f9c75dee6 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 #4 0x00007f8f9c75df31 in std::terminate() () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 #5 0x00007f8f9c75e149 in __cxa_throw () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 #6 0x00007f8f9e661734 in void boost::serialization::throw_exception<boost::archive::archive_exception>(boost::archiv e::archive_exception const&) () from /usr/lib/x86_64-linux- gnu/libboost_serialization.so.1.55.0 #7 0x00007f8f9e67e2f7 in boost::archive::basic_xml_iarchive<boost::archive::xml_iarchive>::load_start(char const*) () from /usr/lib/x86_64-linux-gnu/libboost_serialization.so.1.55.0 #8 0x0000000000486ab4 in boost::archive::basic_xml_iarchive<boost::archive::xml_iarchive>::load_override<std::m ap<int, std::deque<Observation, std::allocator<Observation> >, std::less<int>, std::allocator<std::pair<int const, std::deque<Observation, std::allocator<Observation> > > > > > (this=0x7ffe12327440, t=...) at /usr/include/boost/archive/basic_xml_iarchive.hpp:85 It seems the problem occurs when the std::map<int, std::deque<Observation, std::allocator<Observation> > in Status is loaded. I can't step into frame #7 to checkout the detail of the exception. Could anyone give a hint of the problem. Thanks!

2 1

math.quaternion design issues
by Matwey V. Kornilov 29 Jul '15

29 Jul '15

Hello, I am facing the following performance issues due to internals of quaternion. abs(q) function is quite slow, and most of the time (according to callgrind) is taken to create valarray which is easily unnecessarily here. valarray requires doing malloc and free, because it is dynamic container, at the same time the size of quaternion is 4 and it is fixed. So, was was the purpose to use std::valarray internally?

3 2

input stream error exception during deserializing
by breadbread1984 29 Jul '15

29 Jul '15

I am using xml_oarchive/iarchive to serialize and deserialize a graph. I can serialize successfully but cant deserialize from the output file. An exception of input stream error is throwed out when I deserialize from the file. I paste a small program which can reproduce the problem [here] (http://www.rapidshare.com.cn/jHQIrOv) How could I solve the problem. Thx in advance.

1 0

boost ptree XML parsing for special character
by Uthpal Urubail 29 Jul '15

29 Jul '15

Experts, I am looking for the help in parsing special characters in XML using boost. Original Text: <module>'Admin'</module> Exported Text: <module>'Admin'</module> Using the below code: ptree xmlTree; read_xml("org.txt",xmlTree,boost::property_tree::xml_parser::trim_whitespace); std::string filePath("outFile.txt"); xml_writer_settings<char> settings(' ', 4); boost::property_tree::write_xml(filePath, xmlTree, std::locale(),settings); Any help is highly appreciated Regards, UJ

1 0

building & testing boost with Visual Studio 2015
by Danny K 28 Jul '15

28 Jul '15

I've built boost 1.58 for Visual Studio 2015 RTM. I would like to run the regression tests and submit the results. I am unsure how to do the tests Would someone point me to the documentation about these steps or just let me know what they are? Boost build doesn't know the compiler name. Where do I add that in the bjam scripts? Respectfully, Danny

2 1

Boost.DLL formal review result
by Vladimir Prus 28 Jul '15

28 Jul '15

The Boost.DLL library is accepted. Congratulations to Antony, and thanks for everybody who reviewed the library! The votes were as follows: - Ralf Globisch - Yes - Klaim - Joël Lamotte - Yes - Niall Douglas - Yes, conditionally - John P Fletcher - Yes - Bjorn Reese - Yes - Edward Diener - Yes - Rodrigo Madera - Yes - Richard - Yes I'd like to also thank Thomas Trummer, Rob Stewart and Ion Gaztañaga for their contribution to review. The key suggestions from the review are listed below. None is critical enough to become a formal prerequisite, or require a mini-review. The library can be added when Antony feels its ready. Naming ----------- There was a concern that "DLL" might sound windows specific, and search for best terminology. This does not seem all that important, as soon as documentation introduces the terminology it uses, and is consistent. OSX support ------------------- The library was found not to work on OSX; I believe this issue was already fixed off-list with help from Rodrigo. Documentation ---------------------- Several people requested improvements. Bjorn and John, in particular, pointed out specific issues. This seems to be the post important change prior to adding the library. Dependencies on Boost and system headers ---------------------------------------------------------------- It was suggested that the library does not depend on other Boost C++ Libraries. While it might be helpful to some users, I find it logically impossible for a Boost formal review to request that dependencies on Boost libraries be removed. It was also mentioned that Boost.DLL is header-only library and includes system headers that can bring a lot of symbols and maybe macros. I don't think an actual problem was reported, though, and there is no way to avoid the problem while staying header-only. It's up to the author to consider these suggestions and do something, or don't do anything. Continuous integration -------------------------------- There was a recommendation from Niall to improve CI of the library, including static analysis, valgrind, Windows CI, showing CI status in documentation and so forth. These are good suggestions. At the same time, they are not specific to Boost.DLL, and it's not the goal of a formal review to create new generic development process requirements. Many existing libraries of indisputably high quality do not have these requested mechanisms. Therefore, the author can act on these suggestions as he sees fit. Thanks, -- Vladimir Prus http://vladimirprus.com

4 3