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

Boost.Thread win32 mutex implementations
by Collin Dauphinee 06 Sep '12

06 Sep '12

I was just looking at the win32 implementations of the various Boost.Thread mutex classes (specifically basic_recursive_mutex). I was surprised to see that they use WaitForSingleObject internally, rather than a CRITICAL_SECTION. I've found mentions that it originally used a CRITICAL_SECTION, but no explanation of why it was changed. It seems to me, personally, that the hybrid locking functionality of the CRITICAL_SECTION implementation would be more desirable than the WaitForSingleObject implementation in most use cases. Is there a reason for this choice? At first glance, it looks like it was just done to re-use code from the timed_mutex, which can't (easily) be implemented with CRITICAL_SECTION. Regards, Collin

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Re: [Boost-users] Accessing MSM attribute under specific conditions causes non-compile
by Chiem Whua Ma 06 Sep '12

06 Sep '12

Thank you for your help! I see now that it's not that that the sub-machine is a state of the main machine, but ANY time you have an entry action performed directly from the machine level the fsm is reported as a state and not as an fsm. This isn't a problem since I know this is happening, but perhaps it might be possible to change this so fsm entry actions put the fsm in the fsm parameter slot? What is fsm equal to when an entry action is performed? Here's some code that shows exactly what can be set where and when for anyone else who is trying to figure this out... #include <vector> #include <iostream> #include <boost/msm/back/state_machine.hpp> #include <boost/msm/front/euml/euml.hpp> using namespace std; using namespace boost::msm::front::euml; namespace msm = boost::msm; namespace MSM_A // Concrete FSM implementation { BOOST_MSM_EUML_DECLARE_ATTRIBUTE(int, borrowedBuffer_attribute); BOOST_MSM_EUML_DECLARE_ATTRIBUTE(int, someother_Attribute); BOOST_MSM_EUML_ACTION(someAction) { template <class Event,class FSM,class STATE> void operator()(Event const& event,FSM& , STATE& state) { std::cout<<"Doing someAction."<<std::endl; state.get_attribute(borrowedBuffer_attribute)=1; } }; BOOST_MSM_EUML_ACTION(someOtherAction) { template <class Event,class FSM ,class STATE> void operator()(Event const& event,FSM& fsm, STATE& state) { std::cout<<"Doing someOtherAction."<<std::endl; fsm.get_attribute(borrowedBuffer_attribute)=1; state.get_attribute(someother_Attribute)=1; } }; BOOST_MSM_EUML_EVENT(someevent) BOOST_MSM_EUML_STATE((someOtherAction, no_action, attributes_<<someother_Attribute), someStateA) BOOST_MSM_EUML_STATE((no_action), someStateB) BOOST_MSM_EUML_TRANSITION_TABLE(( someStateA + someevent == someStateB ),transition_table) BOOST_MSM_EUML_DECLARE_STATE_MACHINE(( transition_table, init_ << someStateA, someAction, // <-------------------- ACTION IS AN ENTRY ACTION no_action, attributes_ << borrowedBuffer_attribute, configure_ << no_configure_ ), MSM_A_frontEnd) //fsm name typedef msm::back::state_machine<MSM_A_frontEnd> MSM_A_player; } namespace MSM_B // Concrete FSM implementation { ::MSM_A::MSM_A_player subMachine; BOOST_MSM_EUML_DECLARE_ATTRIBUTE(int, rootFSM_attribute); BOOST_MSM_EUML_DECLARE_ATTRIBUTE(int, rootstate_attribute); BOOST_MSM_EUML_EVENT(someEvent) BOOST_MSM_EUML_ACTION(rootFSM_action) { template <class Event,class FSM,class STATE> void operator()(Event const& event,FSM& , STATE& state) { std::cout<<"Doing rootFSM_action."<<std::endl; state.get_attribute(rootFSM_attribute)=1; } }; BOOST_MSM_EUML_ACTION(another_rootFSM_action) { template <class Event,class FSM,class STATE> void operator()(Event const& event,FSM& fsm , STATE& state) { std::cout<<"Doing another_rootFSM_action."<<std::endl; fsm.get_attribute(rootFSM_attribute)=1; state.get_attribute(rootstate_attribute)=1; } }; BOOST_MSM_EUML_STATE((another_rootFSM_action, no_action, attributes_<<rootstate_attribute), someState) BOOST_MSM_EUML_TRANSITION_TABLE(( someState + someEvent == someEvent ), transition_table) BOOST_MSM_EUML_DECLARE_STATE_MACHINE(( transition_table, //STT init_ << subMachine << someState, rootFSM_action, // Entry no_action, // Exit attributes_ << rootFSM_attribute, // Attributes configure_ << no_configure_ ), MSM_B_frontEnd) //fsm name typedef msm::back::state_machine<MSM_B_frontEnd> MSM_B_player; } int main() { std::cout<<"Making player."<<std::endl; MSM_B::MSM_B_player player; std::cout<<"Starting player."<<std::endl; player.start(); std::cin.ignore(1); return 0; }

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Why is there so much co-dependency in Boost? Is there anything to be done about it?
by steve＠parisgroup.net 06 Sep '12

06 Sep '12

Greetings, As a veteran C++ programmer, I've been an admirer of the Boost library for many years. I've used it at a number of companies I've worked for, especially the SmartPtr library. Right now I'm working for a company that worries a lot about negative exposure to Open Source software issues such as questions that might arise about authorship, copyright or even patent issues. The company does allow the use of Open Source software, but it requires that each piece of code that is brought in first be justified and vetted. Unfortunately, I'm finding this to be a nearly impossible task when I look at the amount of code that must be compiled to use the Boost modules I'm interested in. I've done a study and written some tools, to determine just how many Boost header files must be included to use some of the Boost modules. The numbers are staggering: Any: 79 FileSystem: 276 Smart Ptr: 382 String Algo: 180 I went on and did a tally of which modules these header files came from. Here are the counts for how many other Boost modules each of these modules depends upon: Any: 8 FileSystem: 13 SmartPtr: 8 String Algo: 15 Given these numbers, I think I have to abandon any thoughts of using Boost within my current company. There's no way I'm going to get approval to bring so much code into our work just to get a SmartPtr or FIleSystem library. This is unfortunate, because due to Boost's existence there doesn't seem to be much work going on out there to offer lighter weight alternatives. I'm writing this request in the hopes that there's something I'm missing here, and that someone can point out my folly. Is there a way to utilize any of these Boost modules in such a way that they do not require the inclusion of so much code? If not, does anyone have any suggestions as to how to make this fly with my boss? Has this issue come up before and been considered by the Boost designers? I find the issue baffling. TIA for any help or insight anyone can provide. Steve

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[mpi] broadcast performance
by Brian Budge 06 Sep '12

06 Sep '12

Hi all - I need some advice for using the broadcast function of boost::mpi. We have a large buffer (sometimes gigabytes) that we need to get to all child nodes. We currently use boost::serialization with a binary archive to write the data into a std::vector<char>. Then we send that data across, and deserialize. The data is sent with MPI_Bcast. I've started testing with similar functionality using boost::mpi::broadcast to handle serialization and deserialization. Tracing through the code, it seems that the data is sent to all the child nodes via isend. Is there something I can do to ensure that Bcast will be used instead? If I only have a couple of nodes, the former is fine, but with more nodes, the MPI implementation of Bcast may do a better job (logarithmic or even constant time with the number of nodes). What are the suggestions for getting fast broadcast in this case? I don't think that using skeletons will help, since each instance of the broadcast will have unique data with potentially different layouts. Thanks, Brian

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serialisation use of asserts versus throw ?
by Avi Bahra 06 Sep '12

06 Sep '12

This is question about use of asserts in boost serialisation. As a program migrates from one release to another the api changes. This is expected. In my case I have client/server that uses boost serialisation. I was expecting an throw due to the incompatibility not a an assert. The assert crashes my client, giving no chance for recovery, and informing the user that they are using previous out of date release/server. In may case: boost_iarchive.cpp inline const basic_pointer_iserializer * 399 basic_iarchive_impl::load_pointer( 400 basic_iarchive &ar, 401 void * & t, 402 const basic_pointer_iserializer * bpis_ptr, 403 const basic_pointer_iserializer * (*finder)( 404 const boost::serialization::extended_type_info & type_ 405 ) 406 407 ){ ..... 436 BOOST_ASSERT(NULL != bpis_ptr); 437 class_id_type new_cid = register_type(bpis_ptr->get_basic_serializer()); 438 int i = cid; 439 cobject_id_vector[i].bpis_ptr = bpis_ptr; 440 BOOST_ASSERT(new_cid == cid); // yikes How do people get round this issue, where old and new release of software need to co-exist ? Would it be possible to use a #define to configure use of asserts or throw ? Any help apperciated . Best regards, Ta, Avi

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Boost.Variant: Infinite recursion in constructor
by Markus Lenger 06 Sep '12

06 Sep '12

Hi! I face a problem using Boost.Variant 1.48 under Windows with Cygwin and g++ (GCC) 4.5.3. The following code crashes due to infinite recursion in the constructor of a_t: #include <boost/variant.hpp> #include <iostream> struct a_t { boost::variant< boost::recursive_wrapper<a_t>,int > child; }; int main() { a_t a; std::cout << "OK" << std::endl; return 0; } If I change the type of "child" to "boost::variant< int, boost::recursive_wrapper<a_t> >" (I just swapped the template parameters) the program prints "OK". Any ideas?

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boost dijkstra : retrieve the whole path
by Viviane Parent 06 Sep '12

06 Sep '12

Hello people I'm stubbling on a very stupid problem I think, but I can't find any hint about it. I'm using the boost algorithm dijkstra_shortest_path and I simply want to know how to retrieve all the steps the algo goes through for the shortest path found. To illustrate : I'm glad to know that to go from A to Z, the minimal cost is 26, but I would like also to know that this path goes from A to B then from B to C etc. I used the example http://www.boost.org/doc/libs/1_51 [...] ample.cpp<http://www.boost.org/doc/libs/1_51_0/libs/graph/example/dijkstra-example.cp…> So I ended up with dijkstra_shortest_paths(g, s, &p[0], &d[0], weightmap, indexmap, std::less<int>(), closed_plus<int>(), (std::numeric_limits<int>::max)(), 0,default_dijkstra_visitor()); (I use Visual) Is the info I need somewhere in the visitor, or something ? Thanks for any help you can provide, Sorry for my crappy english V

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Strange linker error
by John M. Dlugosz 06 Sep '12

06 Sep '12

On a Mac, I'm getting a strange linker error, Duplicate symbol typeinfo name for boost::tag_original_exception_type* (in two .o files). Now I only see that name used once in the boost source code, in exception/detail/exception_ptr.hpp, and don't see how it could mean different things in different translation units. Any clue what that's about? —John

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Using a binomial_heap with indirect_cmp
by David Doria 05 Sep '12

05 Sep '12

I am trying to keep a heap sorted by values in a property map. I tried the code below, but the compiler does not like my arguments to the heap constructor (PriorityQueueType pq(indirectComparison);). According to the documentation (http://www.boost.org/doc/libs/1_51_0/doc/html/boost/heap/binomial_heap.html) there is a constructor: explicit binomial_heap(value_compare const & = value_compare()); that takes a value_compare, which I was thinking would of type IndirectComparisonType that I provided (I don't really understand the optional template arguments and the base_maker::compare_argument type of things)? Here is the indirect_cmp doc for reference: http://www.boost.org/doc/libs/1_51_0/boost/pending/indirect_cmp.hpp #include <boost/heap/binomial_heap.hpp> #include <boost/pending/indirect_cmp.hpp> #include <boost/array.hpp> #include <boost/graph/grid_graph.hpp> #include <iostream> int main(int, char*[]) { // Construct a graph boost::array<std::size_t, 2> lengths = { { 2,2 } }; typedef boost::grid_graph<2> GraphType; GraphType graph(lengths); typedef boost::graph_traits<GraphType>::vertex_descriptor Vertex; typedef boost::property_map<GraphType, boost::vertex_index_t>::const_type GridIndexMapType; GridIndexMapType gridIndexMap(get(boost::vertex_index, graph)); // Construct a property map typedef boost::vector_property_map<float, GridIndexMapType> PriorityMapType; PriorityMapType priorityMap(gridIndexMap); // Construct the indirect comparison functor typedef boost::indirect_cmp<PriorityMapType, std::less<float> > IndirectComparisonType; IndirectComparisonType indirectComparison(priorityMap); // Construct the queue typedef int ValueType; typedef boost::heap::binomial_heap<ValueType, boost::heap::stable<false>, IndirectComparisonType> PriorityQueueType; PriorityQueueType pq(indirectComparison); return 0; } Does anyone know how to provide this indirect comparison functor to the queue properly? Thanks, David

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Problems in boost/mpl/aux_/template_arity.hpp when BOOST_MPL_CFG_NO_PREPROCESSED_HEADERS is defined on g++ 4.6.3 and boost 1.50
by Alach 05 Sep '12

05 Sep '12

Hi, Please help. I have encountered a problem on gcc 4.6.3 and boost 1.50 when trying to compile my library with extensive usage of boost::mpl and boost::fusion on gcc. It was required to enable customization of the number of template arguments handled by boost::fusion and boost::mpl containers and mpl meta functions. Not surprisingly the code compiles fine in visual studio 2010. whole code can be found here: svn checkout svn://svn.code.sf.net/p/d-injection/code-0/trunk This is how I have altered template arguments count: #define FUSION_MAX_VECTOR_SIZE DI_MAX_NUM_INJECTIONS #define FUSION_MAX_VECTOR_SIZE DI_MAX_NUM_INJECTIONS #define BOOST_MPL_CFG_NO_PREPROCESSED_HEADERS #define BOOST_MPL_LIMIT_VECTOR_SIZE DI_MAX_NUM_INJECTIONS #define BOOST_MPL_LIMIT_SET_SIZE DI_MAX_NUM_INJECTIONS #define BOOST_MPL_LIMIT_METAFUNCTION_ARITY DI_MAX_NUM_INJECTIONS #include <boost/fusion/include/as_vector.hpp> #include <boost/fusion/include/as_set.hpp> #include <boost/fusion/adapted/mpl.hpp> #include <boost/fusion/include/mpl.hpp> #include <boost/fusion/include/for_each.hpp> #include <boost/fusion/include/at_key.hpp> #include <boost/mpl/vector.hpp> #include <boost/mpl/remove.hpp> #include <boost/mpl/inserter.hpp> #include <boost/mpl/transform.hpp> #include <boost/mpl/insert.hpp> #include <boost/mpl/count.hpp> #include <boost/mpl/copy.hpp> #include <boost/mpl/set.hpp> #include <boost/mpl/inherit.hpp> #include <boost/mpl/joint_view.hpp> #include <boost/mpl/contains.hpp> #include <boost/mpl/size.hpp> #undef FUSION_MAX_VECTOR_SIZE #undef FUSION_MAX_SET_SIZE #undef BOOST_MPL_LIMIT_VECTOR_SIZE #undef BOOST_MPL_LIMIT_SET_SIZE #undef BOOST_MPL_CFG_NO_PREPROCESSED_HEADERS #undef BOOST_MPL_LIMIT_METAFUNCTION_ARITY And I get this error: In file included from ../../libraries/boost_1_50_0/boost/mpl/aux_/full_lambda.hpp:29:0, from ../../libraries/boost_1_50_0/boost/mpl/lambda.hpp:22, from ../../libraries/boost_1_50_0/boost/mpl/apply.hpp:25, from ../../libraries/boost_1_50_0/boost/mpl/aux_/fold_impl.hpp:19, from ../../libraries/boost_1_50_0/boost/mpl/fold.hpp:20, from ../../libraries/boost_1_50_0/boost/fusion/sequence/intrinsic/detail/segmented_size.hpp:12, from ../../libraries/boost_1_50_0/boost/fusion/sequence/intrinsic/size.hpp:16, from ../../libraries/boost_1_50_0/boost/fusion/view/joint_view/joint_view.hpp:15, from ../../libraries/boost_1_50_0/boost/fusion/algorithm/transformation/push_back.hpp:11, from ../../libraries/boost_1_50_0/boost/fusion/view/iterator_range/detail/segmented_iterator_range.hpp:19, from ../../libraries/boost_1_50_0/boost/fusion/view/iterator_range/detail/segments_impl.hpp:13, from ../../libraries/boost_1_50_0/boost/fusion/view/iterator_range/iterator_range.hpp:21, from ../../libraries/boost_1_50_0/boost/fusion/view/iterator_range.hpp:10, from ../../libraries/boost_1_50_0/boost/fusion/sequence/intrinsic/detail/segmented_begin.hpp:12, from ../../libraries/boost_1_50_0/boost/fusion/sequence/intrinsic/begin.hpp:17, from ../../libraries/boost_1_50_0/boost/fusion/container/vector/vector10.hpp:15, from ../../libraries/boost_1_50_0/boost/fusion/container/vector/vector_fwd.hpp:14, from ../../libraries/boost_1_50_0/boost/fusion/container/vector/vector.hpp:10, from ../../libraries/boost_1_50_0/boost/fusion/container/vector/detail/as_vector.hpp:18, from ../../libraries/boost_1_50_0/boost/fusion/container/vector/convert.hpp:10, from ../../libraries/boost_1_50_0/boost/fusion/include/as_vector.hpp:10, from ./di/detail/variadics.hpp:42, from ./di/subject.hpp:10, from test/abstract_builder_should.hpp:11, from test/main.cpp:6: ../../libraries/boost_1_50_0/boost/mpl/aux_/template_arity.hpp:86:1: error: macro "BOOST_PP_TUPLE_ELEM_E_2" requires 2 arguments, but only 1 given ../../libraries/boost_1_50_0/boost/mpl/aux_/template_arity.hpp:86:1: error: macro "BOOST_PP_SEQ_ELEM_III" requires 2 arguments, but only 1 given ../../libraries/boost_1_50_0/boost/mpl/aux_/template_arity.hpp:86:1: error: macro "BOOST_PP_SEQ_ELEM_III" requires 2 arguments, but only 1 given There are more of course, but the consensus is that all errors are somewhat connected to BOOST_PP_ macros. I've tried to find the reason, but with no luck. Thank you in advance, Adam. -- View this message in context: http://boost.2283326.n4.nabble.com/Problems-in-boost-mpl-aux-template-arity… Sent from the Boost - Users mailing list archive at Nabble.com.

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