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[Accumulators] Errors compiling the "Hello, World!" example
by Marco Guazzone 11 Jan '10

11 Jan '10

Hello! I'm new to Accumulators. I've tried to compile the "Hello, World!" example (found in the User Guide) but it fails: --- [error] --- $ g++ -ansi -Wall -o accumulators_test1 accumulators_test1.cpp /usr/include//boost/accumulators/statistics_fwd.hpp: In function ‘int main()’: /usr/include//boost/accumulators/statistics_fwd.hpp:87: error: ‘template<int N> struct boost::accumulators::tag::moment’ is not a function, /usr/include//boost/accumulators/statistics/moment.hpp:104: error: conflict with ‘template<int T2, class Arg1, class A0, class A1, class A2, class A3, class A4, class A5, class A6, class A7, class A8, class A9, class A10, class A11, class A12, class A13, class A14> typename boost::accumulators::detail::extractor_result<Arg1, boost::accumulators::tag::moment<T2> >::type boost::accumulators::extract::moment(const Arg1&, const A0&, const A1&, const A2&, const A3&, const A4&, const A5&, const A6&, const A7&, const A8&, const A9&, const A10&, const A11&, const A12&, const A13&, const A14&)’ accumulators_test1.cpp:22: error: in call to ‘moment’ --- [/error] --- My system is: Fedora 12 x86_64 -- GCC 4.4.2 20091222 (Red Hat 4.4.2-20) -- Boost 1.39 (also tried with the latest Boost trunk) Just for the sake of completeness, here below is the code stored in the "accumulators_test1.cpp" file --- [code] --- #include <iostream> #include <boost/accumulators/accumulators.hpp> #include <boost/accumulators/statistics/stats.hpp> #include <boost/accumulators/statistics/mean.hpp> #include <boost/accumulators/statistics/moment.hpp> using namespace boost::accumulators; int main() { // Define an accumulator set for calculating the mean and the // 2nd moment ... accumulator_set<double, stats<tag::mean, tag::moment<2> > > acc; // push in some data ... acc(1.2); acc(2.3); acc(3.4); acc(4.5); // Display the results ... std::cout << "Mean: " << mean(acc) << std::endl; std::cout << "Moment: " << moment<2>(acc) << std::endl; return 0; } --- [/code] --- Where I am wrong? Thank you very much for any help!! Best, -- Marco

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[repost][serialization] version handling in {save|load}_construct_data
by JOAQUIN M. LOPEZ MUÑOZ 11 Jan '10

11 Jan '10

Hello, allow me to repost this message from a couple of weeks ago: I've taken a look at how the version number is dealt with in Boost.Serialization collection serialization code: * The relevant code at saving time is: if(3 < ar.get_library_version()){ const unsigned int item_version = version< BOOST_DEDUCED_TYPENAME Container::value_type >::value; ar << BOOST_SERIALIZATION_NVP(item_version); } * At loading time, the equivalent code is: unsigned int item_version; ar >> BOOST_SERIALIZATION_NVP(count); if(3 < ar.get_library_version()) ar >> BOOST_SERIALIZATION_NVP(item_version); else item_version = 0; Can someone (aka Robert :-) ) shed some light on this bit? Why the version number has to be given such manual processing when this is not needed if, for instance, serializating values via the simple ar&value? I'm trying to do the equivalent thing in Boost.MultiIndex. Thank you, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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Re: [Boost-users] boost.m4 checks correct header but detects wrong header version
by Peter Schueller 11 Jan '10

11 Jan '10

Hi Tsuna, On Mon, Jan 11, 2010 at 08:30, tsuna <tsunanet(a)gmail.com> wrote: > On Mon, Aug 24, 2009 at 1:57 AM, Peter Schueller <ps(a)kr.tuwien.ac.at> wrote: >> (posting to the boost-users list and to the boost.m4 maintainer) > > Hi Peter, > sorry for the belated reply. No problem at all. >> I have several boost installations, among others a 1.34.1 in >> /usr/include and several in my homedir in >> /home/staff/ps/include/boost-1_36/ >> /home/staff/ps/include/boost-1_37/ >> /home/staff/ps/include/boost-1_39/ >> >> Calling configure with --with-boost=/home/staff/ps/include/boost-1_37/ >> I get the following information: >> >> checking for Boost headers version >= 103300... >> /home/staff/ps/include/boost-1_37/include >> checking for Boost's header version... 1_34_1 >> >> The first check finds the correct headers, the second one uses the wrong ones. > > I believe this issue has been fixed by > http://github.com/tsuna/boost.m4/commit/93faeb67fbbc5d68a397c64ebc2dddf23a9… > > Can you retry with the latest version and let me know if it still > doesn't work for you? Thank you very much, this indeed resolves the issue! > Happy new year! Happy new year to you as well! Best Regards, Peter -- Peter Schüller Vienna University of Technology, Institute of Information Systems Favoritenstrasse 9-11/1843, 1040 Wien, Austria T: +43 1 58801 18470 E: ps(a)kr.tuwien.ac.at DVR: 0005886 http://www.kr.tuwien.ac.at/staff/ps

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Re: [Boost-users] [repost][serialization] version handling in{save|load}_construct_data
by JOAQUIN M. LOPEZ MUÑOZ 10 Jan '10

10 Jan '10

________________________________________ De: boost-users-bounces(a)lists.boost.org [boost-users-bounces(a)lists.boost.org] En nombre de Robert Ramey [ramey(a)rrsd.com] Enviado el: domingo, 10 de enero de 2010 20:22 Para: boost-users(a)lists.boost.org Asunto: Re: [Boost-users] [repost][serialization] version handling in{save|load}_construct_data > > I investigated a little bit more. Seems that save/load_construct data needs > the version # and there is no place else to get it. Why can't you directly use serialization::version<T>::value? This is for instance what you're doing at lines 51 and following of boost/serialization/hash_collections_save_imp.hpp. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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Re: [Boost-users] [repost][serialization] version handling in{save|load}_construct_data
by JOAQUIN M. LOPEZ MUÑOZ 10 Jan '10

10 Jan '10

________________________________________ De: boost-users-bounces(a)lists.boost.org [boost-users-bounces(a)lists.boost.org] En nombre de Robert Ramey [ramey(a)rrsd.com] Enviado el: sábado, 09 de enero de 2010 21:40 Para: boost-users(a)lists.boost.org Asunto: Re: [Boost-users] [repost][serialization] version handling in{save|load}_construct_data > I believe that this came about when error to the serialization of > collections was discovered. Previous library versions didn't > properly save the version of the collection item. When this > was corrected, this code was needed to permit the the loading > of archives created previously. > > If the type isn't versioned (e.g. some primitive type), then the > default version # would be zero. I suppose this could be > made more elaborate so that the version # wouldn't even > be in the archive in these cases - but that's not way we did it. > > I don't know if that answers your question, but that's what > I remember about it. I'm afraid that does not entirely answer my question. I understand what the "if(3 < ar.get_library_version()){" guard is for. What puzzles is me is why you need to explicitly save the type serialization version number when this info is seemingly recovered in other contexts without any explicit user operation. Let me put it another way: consider a user defined type my_type with associated serialization code: template<class Archive> void serialize(Archive& ar,my_type & m,const unsigned int version) { ... } When serialize() is called internally by Boost.Serialization, version is correctly passed without the user explicitly saving this info as it happens in the code for collection serialization. Why this difference? Am i making myself clear as to what the root of my puzzlement is? Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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BOOST_FUSION_ADAPT_STRUCT
by Hicham Mouline 09 Jan '10

09 Jan '10

Hello, Can I use this macro with specialized templates as well? template <typename T> struct range { T min ; T max ; } ; BOOST_FUSION_ADAPT_STRUCT( range<double>, (double, min) (double, max) } Rds,

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[BGL] dijkstra_shortest_paths with listS
by gast128 09 Jan '10

09 Jan '10

Hello all, BGL supports a lot of graph algorithms, and lots of stuff get default filled in when using vecS as container type of vertices. However things become pretty ugly when not using this container. Below I used a listS for both edges and vertices. Maybe it can help other people (and maybe somebody can cross check me). Note that some constructs could be bundled, but for clearity I explicitly wrote all things out. I use the graph from the BGL book as example (figure 13.3). void TestgraphDijkstra() { typedef boost::adjacency_list<boost::listS, boost::listS, boost::bidirectionalS, std::string> Graph; typedef boost::graph_traits<Graph>::vertex_descriptor VertexDescriptor; typedef boost::graph_traits<Graph>::edge_descriptor EdgeDescriptor; typedef int Weight; typedef std::map<EdgeDescriptor, Weight> WeightMap; typedef std::map<VertexDescriptor, size_t> VertexIndexMap; typedef std::map<VertexDescriptor, Weight> DistanceMap; typedef std::map<VertexDescriptor, VertexDescriptor> PredecessorMap; Graph graph; WeightMap mapWeigth; VertexIndexMap mapVertexIndex; DistanceMap mapDistance; PredecessorMap mapPredecessor; boost::associative_property_map<WeightMap> pmWeigth(mapWeigth); boost::associative_property_map<VertexIndexMap> pmVertexIndex (mapVertexIndex); boost::associative_property_map<DistanceMap> pmDistance(mapDistance); boost::associative_property_map<PredecessorMap> pmPredecessor (mapPredecessor); //build a graph according to figure 13.3 //add vertices const VertexDescriptor vA = boost::add_vertex(graph); const VertexDescriptor vB = boost::add_vertex(graph); const VertexDescriptor vC = boost::add_vertex(graph); const VertexDescriptor vD = boost::add_vertex(graph); const VertexDescriptor vE = boost::add_vertex(graph); //set vertex names graph[vA] = "A"; graph[vB] = "B"; graph[vC] = "C"; graph[vD] = "D"; graph[vE] = "E"; //add edges const EdgeDescriptor eAC = boost::add_edge(vA, vC, graph).first; const EdgeDescriptor eBB = boost::add_edge(vB, vB, graph).first; const EdgeDescriptor eBD = boost::add_edge(vB, vD, graph).first; const EdgeDescriptor eBE = boost::add_edge(vB, vE, graph).first; const EdgeDescriptor eCB = boost::add_edge(vC, vB, graph).first; const EdgeDescriptor eCD = boost::add_edge(vC, vD, graph).first; const EdgeDescriptor eDE = boost::add_edge(vD, vE, graph).first; const EdgeDescriptor eEB = boost::add_edge(vE, vB, graph).first; const EdgeDescriptor eEA = boost::add_edge(vE, vA, graph).first; //set edge weights boost::put(pmWeigth, eAC, 1); boost::put(pmWeigth, eBB, 2); boost::put(pmWeigth, eBD, 1); boost::put(pmWeigth, eBE, 2); boost::put(pmWeigth, eCB, 7); boost::put(pmWeigth, eCD, 3); boost::put(pmWeigth, eDE, 1); boost::put(pmWeigth, eEB, 1); boost::put(pmWeigth, eEA, 1); //build index map boost::put(pmVertexIndex, vA, 0); boost::put(pmVertexIndex, vB, 1); boost::put(pmVertexIndex, vC, 2); boost::put(pmVertexIndex, vD, 3); boost::put(pmVertexIndex, vE, 4); //note: color map not needed, because of index map? boost::dijkstra_shortest_paths(graph, vA, boost::weight_map (pmWeigth).vertex_index_map(pmVertexIndex).distance_map (pmDistance).predecessor_map(pmPredecessor)); for (DistanceMap::const_iterator itDist = mapDistance.begin(); itDist != mapDistance.end(); ++itDist) { //dump const VertexDescriptor v = itDist->first; const VertexDescriptor vPrev = mapPredecessor[v]; std::cout << "Distance(" << graph[v] << ") = " << itDist->second << ", " << "Parent(" << graph[v] << ") = " << graph[vPrev] << std::endl; } }

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Non-Boost question: HTML parser with hpricot
by Boost lzw 09 Jan '10

09 Jan '10

Hi folks, Sorry for posting a question unrelated to boost. I know pretty well that boost has perfect solutions to it. But I am working on a legacy system using Hpricot of Ruby on Rail. So only Hpricot-specific suggestions please. Thank you. In my HTML parser, I can parse a html file with the following hpricot commands: (1) doc = open( "MyFileToParse.html" ) { |f| Hpricot(f) } (2) elements = (doc.search("/html/body/table/tr/td/table/tr/td/font") ) (3) puts (elements[13]).inner_html to get the following output: Giaever G, et al (2002). Functional profiling of the Saccharomyces c erevisiae genome. Nature, 418:387-91. [<a href=" http://www.ncbi.nlm.nih.gov/entr ez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12140549&dopt=Abstract" target="_ blank">PubMed</a>] How can I proceed to get the following results (3) and (4) respectively? (3) Giaever G, et al (2002). Functional profiling of the Saccharomyces c erevisiae genome. Nature, 418:387-91. (4) http://www.ncbi.nlm.nih.gov/pubmed/12140549?dopt=Abstract NOTE: to get (4) I need to take two more steps: (5) replace "&" with "?" (6) replace "PubMed" with "pubmed" (this might be trivial, but how?) in the process of parsing in addition to "normal" HTML parsing. Thanks a lot in advance. Robert

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Problem with boost::thread::sleep
by Rob Yull 08 Jan '10

08 Jan '10

Using Boost 1.41, MSVC 2005, Win 7 x64 (compiling 32-bit). I was trying to set a small delay in a loop, so the loop doesn't consume all of the processor, using boost::thread::sleep(). I tried using the example from the threading documentation (http://www.boost.org/doc/libs/1_41_0/doc/html/thread/time.html#thread.time. get_system_time): boost::thread::sleep(boost::posix_time::milliseconds(25)); I keep getting a compiler error from the line above. Error 2 error C2664: 'boost::thread::sleep' : cannot convert parameter 1 from 'boost::date_time::subsecond_duration<base_duration,frac_of_second>' to 'const boost::system_time &' Is there something else I need to be doing to make this work? -Rob Yull

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Automatic thread join
by Lloyd 08 Jan '10

08 Jan '10

Hi, Is there a way to join a thread automatically to the main thread when it finishes execution? In my case, the main thread does not call the "thread->join()", so even if the work of the thread is over, the thread never joins to the main thread. What is the technique usually used to make a thread join to its main thread, so as to avoid wastage of resources. Thanks, Lloyd ___________________ Happy New Year 2010

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boost::crc - newbie help
by Paul Caswell 08 Jan '10

08 Jan '10

Hello all, I've the task of implementing the following CRC computation and was wondering whether I could use boost::crc to save me a lot of hassle. ------------------------ Default 32-bit Parity (CRC) This 32-bit CRC is the same as that described in EKMS 304 ([6]) and EKMS 322 ([8]) and could be used as a CRC method in the keyAlgorithm Attribute (with OID { 1 2 826 0 1145 0 5 1 }). Let g(x) be the polynomial x32 + x22 + x2 + x + 1. Let d(x) be the k bits of data to have parity applied to them. The first bit of data is the coefficient of the (k-1)st power of x etc. Let f(x) be the polynomial naturally represented by the initial fill 0xF8DD4258, i.e. x31 + x30 + x29 + x28 + x27 + x23 + x22 + x20 + x19 + x18 + x16 + x14 + x9 + x6 + x4 + x3. Then the output is c(x) = x32d(x) + xkf(x) mod g(x). The polynomial c(x) is then interpreted as a stream with the coefficient of x31 coming first and the coefficient of x0 coming last. The 32-bit parity is then c(x). This calculation can be done using a simple shift register as shown below. The shaded stages represent ones in the initial fill. The logic steps k times to determine c(x), which is the final state of the register. <diagram omitted> ------------------------ Any advice and or help would be appreciated. Regards, Paul This email and any files transmitted with it may be confidential, legally privileged and protected in law and are intended solely for the use of the individual to whom it is addressed. Any view or opinions presented are solely those of the author and do not necessarily represent those of Stonewood Group Ltd. If you have received this Email in error please contact the sender by return and confirm that its contents have been destroyed without further distribution or disclosure. Please email admin(a)stonewood.co.uk with any questions relating to this disclaimer. Stonewood Group Ltd has Registered Offices at Sandford Lane, Wareham, Dorset BH20 4DY. The company is registered in England and Wales under no: 3007498.

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Thread not interrupted in runtime linked library
by Lloyd 08 Jan '10

08 Jan '10

Hi, Using boost thread a new thread is created. The thread loads a DLL using LoadLibrary() call, gets the procedure address by calling GetProcAddress() and executes the procedure. The body of procedure is an infinite loop. When I try to interrupt the thread from main thread it is not interrrupted! What could be the reason? In all other cases the thread is interrupted except when it is inside the dynamically (runtime) linked library procedure. What could be the reason? Please share some idea... Thank you very much Lloyd ___________________ Happy New Year 2010

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Xpressive continuing search from previous match
by K. Noel Belcourt 08 Jan '10

08 Jan '10

Hi, I have a search for a regular expression like this. sregex_iterator cur(buffer.begin(), buffer.end(), defined_re), end; for(; cur != end; ++cur) { ... But what I really want to do is perform a new regex search starting at the location in the buffer marking the end of the previous search. Is there a way to get the buffer index from the previous search so I can start the new search past the previous search? I apologize if this is easy to do, I must have missed it with my quick perusal through the documentation. Thanks. -- Noel Belcourt

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Defining Statements with Proto
by David A. Greene 08 Jan '10

08 Jan '10

A few years ago, I asked how to define a grammar with Proto to match something like this: if_(expr) [ stmt, stmt, ... ].else [ stmt, stmt, ... ]; The answer was to do this: struct Grammar; struct ExpressionGrammar; struct StatementGrammar; struct Domain; template<typename Expr> struct Expression : proto::extends<Expr, Expression<Expr>, Domain> { typedef proto::extends<Expr, Expression<Expr>, Domain> base_type; Expression(Expr const & expr = Expr()) : base_type( expr ) {} }; struct Domain : proto::domain< proto::generator< Expression >, Grammar> {}; struct If {}; BOOST_PROTO_DEFINE_FUNCTION_TEMPLATE( 1 , if_ , Domain , (If) , BOOST_PP_SEQ_NIL ); // Here is the grammar for if_ statements // matches if_(e1)[e2] struct IfGrammar : boost::proto::subscript< boost::proto::arg< boost::proto::unary_expr< If, ExpressionGrammar >, >, StatementGrammar > {}; // An else_ "operator" template<typename Expr> struct Expression< Expr , typename enable_if<proto::matches<Expr, IfGrammar> >::type > : proto::extends<Expr, Expression<Expr>, Domain> { Expression() : else_(proto::make_expr<Else>(*this)) {}; proto::result_of::make_expr< Else, // else is now an "operator" Expression<Expr> const >::type const else_; }; // matches if_(e1)[e2].else_[e3] struct IfElseGrammar : boost:proto::subscript< boost::proto::arg< boost::proto::unary_expr< Else, IfGrammar >, >, StatementGrammar > {}; I didn't understand it then and I don't now. :) However, it seems to be obsolete since BOOST_PROTO_DEFINE_FUNCTION_TEMPLATE doesn't seem to exist anymore (it's not documented, anyway). So how would this be formulated in modern Boost.Proto? I'm guessing I will need an expression template wrapper (called Expression<> above) that uses some combination of BOOST_PROTO_BASIC_EXTENDS, BOOST_PROTO_EXTENDS_SUBSCRIPT and BOOST_PROTO_EXTENDS_FUNCTION. But of course not all statements have a valid operator() overload and no expressions do. I guess the grammar will take care of that, yes? I'm really puzzled about how to do the ".else_" part. I was hoping I could look to Phoenix to get a clue but it doesn't seem to use Proto. Any help? Thanks! -Dave

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[foreach] BOOST_FOREACH question...
by barcaroller 08 Jan '10

08 Jan '10

Does the BOOST_FOREACH macro work for empty sequences or must a size check be done explicitly? list<int> mylist; if (!mylist.empty()) // <--- necessary? { foreach(int& i, mylist) { // take action } } The reason I ask is that neither begin() nor end() return valid iterators for empty sequences, but it is my understanding that BOOST_FOREACH needs iterators to work properly.

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fusion and mpl
by Peter Foelsche 08 Jan '10

08 Jan '10

I need to be able to convert a mpl sequence into something like a tuple: typedef boost::mpl::vector<double> CMplSequence; typedef CCreateVectorFromMpl<CMplSequence>::type CVector; I need to have runtime access with constant index: CVector s; get<0>(s) = 1.0; std::cout << get<0>(s) << "\n"; I need to be able to retrieve the type at compile time: typedef CGetType<CVector, boost::mpl::long_<0> >::type CFirstType; I already wrote something like this using std::pair as the tuple but I'm running into problems storing reference types on Windows. Peter

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boost::multi_array equivalent for runtime number of dimensions
by Hicham Mouline 07 Jan '10

07 Jan '10

Hello, I only know at runtime the dimension and extends of a multidimensional array, though the number of dimensions is always < 10 for e.g. Is there a container that allows this? Otherwise, I can write code for multi_array<T, 2> multi_array<T, 3> . multi_array<T, 10>, do a switch case on the dimensions variable, and select the appropriate code, regards,

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[Math/Statistical Distributions+Random] Random number generation
by Marco Guazzone 07 Jan '10

07 Jan '10

Hi all! I'm a "boost newbie" so sorry for too trivial questions. Just trying to use boost for some statistical experiments, involving statistical distribution fitting, quantile generation (for goodness-of-fit tests), random variate generation, and so on. . The "Math/Statistical Distribution" library is great and almost complete. But I'm just curious why the random number generation (provided by the "Random" lib) and this library have not been integrated. For instance, the boost::random::exponential_distribution and the boost::math::exponential_distribution are two different worlds. I think a function like this below would be very helpful: --- [snip] --- template <typename Generator, typename RealType, typename Policy> inline RealType rand(Generator& rng, const exponential_distribution<RealType, Policy>& dist) { return -1.0 / dist.lambda() * std::log(1.0-rng()); } --- [snip] --- or something similar (e.g., rand implemented as a class method) In this case only two objects are needed: * boost::random::mersenne_twister * boost::math::exponential_distribution Instead, actually I have to keep different objects. For instance, for the exponential distribution: * boost::random::exponential_distribution * boost::random::mersenne_twister * boost::random::variate_generator * boost::math::exponential_distribution Unluckely I can't use boost::math::exponential_distribution in place of boost::random::exponential_distribution since boost::random::variate_generator expects a specific interface for the distribution. Well, what is the rationale behind the choice of this separation? Do you think would be useful to provide this kind of integration? Thank you very much in advance!! Cheers -- Marco

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Re: [Boost-users] BGL: shared_ptr as bundled properties > how to generate properties maps ???
by Damien Maupu 07 Jan '10

07 Jan '10

>On Wed, 6 Jan 2010, Emil Dotchevski wrote: > > On Wed, Jan 6, 2010 at 8:20 AM, Damien Maupu <damien.maupu_at_[hidden]> wrote: >>> I write something like: >>> typedef boost::shared_ptr<Vertex> VertexPtr; >>> typedef boost::shared_ptr<Edge> EdgePtr; >>> typedef adjacency_list<vecS, vecS, directedS, VertexPtr, EdgePtr> Graph; >> >> It is probably not a good idea to use shared_ptr for graphs; some >> graphs have cycles and this will lead to leaks (if your data structure >> is a DAG, you're fine.) >I don't think that will be an issue -- his shared pointers link to >properties; the graph structure itself is in BGL data structures. >However, if the properties refer to other graph vertices or edges, there >is an issue of dangling references if those objects are removed from the >graph. >-- Jeremiah Willcock Hi, I am not sure I understand why using smart pointer should be an issue. Could you explain me in little more details? Do you know how to get properties maps if bundle properties are pointer or smart pointers? Thank you Damien

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ASIO async_read_until with condition + strand
by Christophe Bourez 07 Jan '10

07 Jan '10

Can someone help with the boost async_read_until with condition ? I need to implement a request/response protocol. * A request cannot be send until the response has been completely read from the server. * Response's length from the server is unknown. The data must be parsed thanks to a parser to understand the content of the buffer. The parser is capable to return a code specifying whether the data is complete, which could require more reading on the socket. I'd like to implement my client asynchronously using ASIO. Here is the solution I implemented: the async send handler calls async_read whose handler calls async_read handler again until the message is complete. Due to the here above constraints, I am forced to queue the requests and async send the next request by the end of the handler of the current response (when it is complete, otherwize it async_reads again). I have tried to use async_read_until with a condition, but the parser was invoked very (too) often (every 2 bytes) and penalizes the performance. Would it be possible to reduce the number of calls to the condition (by reading at once the maximum of bytes present on the socket for example)? I'd like to async send the requests as soon as I can, in order to avoid the queue. Is it possible to implement a solution by using the ASIO strands? If yes, I have the feeling that the way I implemented the response handling will not work with the strand because the handler of async_read calls async_read again, which will probably come at the end of the strand's queue (which may contain many async_send requests). Could async_read_until with a condition solves this issue by avoiding to async_read again? Any help will be very appreciated. Christophe

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[thread] Getting this warning message with optimization turn on
by Shiou Ming Lee 07 Jan '10

07 Jan '10

Hi, I'm building my program that depends on Boost.thread, but getting following warning message, only when compiler's optimization been turn on. C:/boost_1_41_0/boost/thread/win32/thread_heap_alloc.hpp: In member function `bool gUtil::GLog::LogWriterManager::startAsyncLogging(unsigned int)': C:/boost_1_41_0/boost/thread/win32/thread_heap_alloc.hpp:156: warning: 'heap_memory' might be used uninitialized in this function In the mentioned function, startAsyncLogging(unsigned int), there's only one line of code that involves Boost.thread: // loggingThread is class LogWriterManager's member, of boost::thread type. loggingThread = boost::thread(boost::bind(&LogWriterManager::loggingThreadFunc, this)); This happens for MinGW 3.4 on Windows Vista SP1 32-bits, but not for GCC 4.4 on Fedora 11 x86. The Boost release is of version 1.41.0. Any idea what should I do for this warning message? Or should I just leave optimization on and ignore this message? Thanks & Regards Shiou Ming

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[Signals2] How to connect member functions with more than one argument?
by Marco Guazzone 07 Jan '10

07 Jan '10

Dear all, I am new to Boost.Signals2, so sorry for the possibly trivial question. My problem is that I am not able to connect a member function with more than one argument to a signal. My test code is the following: --- [code] --- #include <boost/bind.hpp> #include <boost/signals2.hpp> #include <iostream> template <typename IntT=int, typename RealT=double> struct event_consumer { typedef IntT int_type; typedef RealT real_type; typedef boost::signals2::signal<void (int_type,real_type)> signal_type; typedef event_consumer<int_type,real_type> self_type; void consume() { sig.connect(boost::bind(&self_type::process, this, _1)); sig(2,0.5); } void process(int_type x, real_type y) { std::cout << "X: " << x << " -- Y: " << y << std::endl; } signal_type sig; }; int main() { event_consumer<> consumer; consumer.consume(); } --- [/code] --- When I compile it (with g++ 4.4.2 and flags --ansi --Wall) I get this error: --- [error] --- $ g++ -Wall -ansi -o test_signal test_signal.cpp In file included from .../boost/bind.hpp:22, from test_signal.cpp:1: .../boost/bind/bind.hpp: In instantiation of ‘boost::_bi::result_traits<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double)>’: ...//boost/bind/bind_template.hpp:15: instantiated from ‘boost::_bi::bind_t<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double), boost::_bi::list2<boost::_bi::value<event_consumer<int, double>*>, boost::arg<1> > >’ test_signal.cpp:15: instantiated from ‘void event_consumer<IntT, RealT>::consume() [with IntT = int, RealT = double]’ test_signal.cpp:32: instantiated from here .../boost/bind/bind.hpp:69: error: ‘void (event_consumer<int, double>::*)(int, double)’ is not a class, struct, or union type In file included from ...//function/detail/maybe_include.hpp:23, from .../boost/function/detail/function_iterate.hpp:14, from .../boost/preprocessor/iteration/detail/iter/forward1.hpp:57, from .../boost/function.hpp:64, from .../boost/signals2/signal.hpp:18, from .../boost/signals2.hpp:16, from test_signal.cpp:2: .../boost/function/function_template.hpp: In static member function ‘static void boost::detail::function::void_function_obj_invoker2<FunctionObj, R, T0, T1>::invoke(boost::detail::function::function_buffer&, T0, T1) [with FunctionObj = boost::_bi::bind_t<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double), boost::_bi::list2<boost::_bi::value<event_consumer<int, double>*>, boost::arg<1> > >, R = void, T0 = int, T1 = double]’: .../boost/function/function_template.hpp:913: instantiated from ‘void boost::function2<R, T1, T2>::assign_to(Functor) [with Functor = boost::_bi::bind_t<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double), boost::_bi::list2<boost::_bi::value<event_consumer<int, double>*>, boost::arg<1> > >, R = void, T0 = int, T1 = double]’ .../boost/function/function_template.hpp:722: instantiated from ‘boost::function2<R, T1, T2>::function2(Functor, typename boost::enable_if_c<boost::type_traits::ice_not::value, int>::type) [with Functor = boost::_bi::bind_t<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double), boost::_bi::list2<boost::_bi::value<event_consumer<int, double>*>, boost::arg<1> > >, R = void, T0 = int, T1 = double]’ .../boost/function/function_template.hpp:1064: instantiated from ‘boost::function<R(T0, T1)>::function(Functor, typename boost::enable_if_c<boost::type_traits::ice_not::value, int>::type) [with Functor = boost::_bi::bind_t<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double), boost::_bi::list2<boost::_bi::value<event_consumer<int, double>*>, boost::arg<1> > >, R = void, T0 = int, T1 = double]’ .../boost/function/function_template.hpp:1105: instantiated from ‘typename boost::enable_if_c<boost::type_traits::ice_not::value, boost::function<R(T0, T1)>&>::type boost::function<R(T0, T1)>::operator=(Functor) [with Functor = boost::_bi::bind_t<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double), boost::_bi::list2<boost::_bi::value<event_consumer<int, double>*>, boost::arg<1> > >, R = void, T0 = int, T1 = double]’ .../boost/signals2/detail/slot_template.hpp:156: instantiated from ‘void boost::signals2::slot2<R, T1, T2, SlotFunction>::init_slot_function(const F&) [with F = boost::_bi::bind_t<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double), boost::_bi::list2<boost::_bi::value<event_consumer<int, double>*>, boost::arg<1> > >, R = void, T1 = int, T2 = double, SlotFunction = boost::function<void(int, double)>]’ .../boost/signals2/detail/slot_template.hpp:81: instantiated from ‘boost::signals2::slot2<R, T1, T2, SlotFunction>::slot2(const F&) [with F = boost::_bi::bind_t<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double), boost::_bi::list2<boost::_bi::value<event_consumer<int, double>*>, boost::arg<1> > >, R = void, T1 = int, T2 = double, SlotFunction = boost::function<void(int, double)>]’ test_signal.cpp:15: instantiated from ‘void event_consumer<IntT, RealT>::consume() [with IntT = int, RealT = double]’ test_signal.cpp:32: instantiated from here .../boost/function/function_template.hpp:153: error: no match for call to ‘(boost::_bi::bind_t<boost::_bi::unspecified, void (event_consumer<int, double>::*)(int, double), boost::_bi::list2<boost::_bi::value<event_consumer<int, double>*>, boost::arg<1> > >) (int&, double&)’ --- [/error] --- Thank you very much for the support!!! Best, -- Marco

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[Preprocessor] how to use REPEAT_FROM_TO for 2 arguments
by Kai Liu 07 Jan '10

07 Jan '10

Hi, I am trying to use the preprocessor library to simplify the code I have. The problem: I have many lines of the following assignments: mybfclass x_0_mybf; mybfclass x_1_mybf; ... mybfclass1 x_0_mybf1; mybfclass1 x_1_mybf1; ... mybfclass2 x_0_mybf2; mybfclass2 x_1_mybf2; then I defined several vectors: vector<mybfclass*> x_mybf; vector<mybfclass1*> x_mybf1; vector<mybfclass2*> x_mybf2; * use the boost preprocessor library, I write the following code: #define* DECLX_mybf(z, n, text) BOOST_PP_CAT(text, BOOST_PP_CAT(_, mybf)).push_back(&BOOST_PP_CAT(text, BOOST_PP_CAT(BOOST_PP_CAT(_, n), BOOST_PP_CAT(_, mybf)))); *#define* DECLX_mybf1(z, n, text) BOOST_PP_CAT(text, BOOST_PP_CAT(_, mybf)).push_back(&BOOST_PP_CAT(text, BOOST_PP_CAT(BOOST_PP_CAT(_, n), BOOST_PP_CAT(_, mybf)))); *#define* DECLX_mybf2(z, n, text) BOOST_PP_CAT(text, BOOST_PP_CAT(_, mybf)).push_back(&BOOST_PP_CAT(text, BOOST_PP_CAT(BOOST_PP_CAT(_, n), BOOST_PP_CAT(_, mybf)))); BOOST_PP_REPEAT_FROM_TO(0, 2, DECLX_mybf, x); *// generated: x_mybf.push_back(&x_0_mybf); x_mybf.push_back(&x_1_mybf); * BOOST_PP_REPEAT_FROM_TO(0, 2, DECLX_mybf1, x); *// generated: x_mybf1.push_back(&x_0_mybf1); x_mybf1.push_back(&x_1_mybf); * BOOST_PP_REPEAT_FROM_TO(0, 2, DECLX_mybf2, x); *// generated: x_mybf2.push_back(&x_0_mybf2); x_mybf2.push_back(&x_1_mybf); * but I think it is too much coding here, since I have to write a macro for each mybf occurrence, DECLX_mybf I have difficulty to use the BOOST_PP_REPEAT_FROM_TO for two argument, since the macro(z, x, data) can only accept one argument data, however, I need to pass two arguments x and mybf to the macro, in order to generate a mybfclass1 x_0_mybf. does anyone know how to apply macro to generate the above structure? thanks. /Kenny * *

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[BGL] simple problem: how to detect connections in a dag?
by Olaf Krzikalla 06 Jan '10

06 Jan '10

Hi @boost, we have a rather simple problem here for which we however couldn't find a simple solution in the BGL. Probably because we aren't graph experts. We have a dag and two vertices in this dag. Now we just want to know if these vertices are connected (acrtually we don't need the path), that is if one vertex is in a parent chain of the other. Thanks in advance Olaf Krzikalla

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Re: [Boost-users] [asio] Sending large packages
by Nicola Michael Gutberlet 06 Jan '10

06 Jan '10

Doesn't anyone have any ideas? Did anyone receive this mail? Best regards and a happy new year ;-) _____ From: Nicola Michael Gutberlet [mailto:nicola.gutberlet@hhi.fraunhofer.de] Sent: 15 December 2009 17:28 To: 'boost-users(a)lists.boost.org' Subject: RE: [asio] Sending large packages Some testing showed that the maximum package (load) size of boost::asio::write/read() for a TCP socket seems to be 1007 kB _____ From: Nicola Michael Gutberlet [mailto:nicola.gutberlet@hhi.fraunhofer.de] Sent: 15 December 2009 17:11 To: 'boost-users(a)lists.boost.org' Subject: [asio] Sending large packages Dear all, Is there a well-defined way of sending large packages over TCP? Or do I have to split the packages on my own? For explanation: I want to send images (size around 6MB). Best regards, Nicola

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