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Since which boost-version is linking against boost-system required?
by Cedric Laczny 16 Jun '11

16 Jun '11

Hi, I have an application which compiles fine with boost-1.40 and 1.41 (global installation). When I try to compile that application on a system with a local (staged) installation of boost-1.46.0, it complains about undefined reference to `boost::system::get_system_category()' etc. So, now, it has to be linked also to boost-system via -lboost-system. Linking against boost_filesystem and boost_regex ist already specified. So far, so good. My question is now, since when is this required? Thank you. Best, Cedric

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Re: [Boost-users] [statechart] Is it possible to have nested (sub)states in an asynchronous state machine?
by Gurcan Gulesir 16 Jun '11

16 Jun '11

> I don't know what compiler you used and what your real code looked > like, but when I tried to compile some portions of your sample code > with VC10, I got a lot of "use of undefined type" errors. I am using Eclipse IDE for C/C++ Helios Service Release 2 and Ubuntu 10.04 LTS with its built-in GCC C++ compiler and linker. My software uses Linux-specific libraries, so VC10 is currently not an option for me. If I encounter any additional problems, then I will first compile the "skeleton code" of my state machines in VC10, find and solve the problem there, and then port the solution to Eclipse in Ubuntu. So, thanks for the tip!

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Serialize a vector of lists with boost
by Alessandro Candini 16 Jun '11

16 Jun '11

Hi all. I have a program, simplified as follows: |#include<vector> #include<list> #include<fstream> using namespace std; class MyObj { int val; public: MyObj(int v){ val = v; }; ~MyObj(){}; }; int main (int argc,char *argv[]) { int i, j; vector< list<MyObj*> > layers; for(i=0; i<5; i++) { list<MyObj*> tmp; for(j=0; j<10; j++) tmp.push_back(new MyObj(j) ); layers.push_back(tmp); } return 0; }| I need to serialize/deserialize the object "layers". Can anyone give me an example on how to do this with boost serialization library? Thanks in advance. -- Alessandro Candini MEEO S.r.l. Via Saragat 9 I-44122 Ferrara, Italy Tel: +39 0532 1861501 Fax: +39 0532 1861637 http://www.meeo.it ======================================== "ATTENZIONE:le informazioni contenute in questo messaggio sono da considerarsi confidenziali ed il loro utilizzo è riservato unicamente al destinatario sopra indicato. Chi dovesse ricevere questo messaggio per errore è tenuto ad informare il mittente ed a rimuoverlo definitivamente da ogni supporto elettronico o cartaceo." "WARNING:This message contains confidential and/or proprietary information which may be subject to privilege or immunity and which is intended for use of its addressee only. Should you receive this message in error, you are kindly requested to inform the sender and to definitively remove it from any paper or electronic format."

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A doubt in Boost Format
by Gokulakannan Somasundaram 16 Jun '11

16 Jun '11

Hi, We are using Boost format in our project. We want to replace the normal allocator with a special allocator and we don't want any allocation be made with normal new. I was looking at the Boost fusion reference. format_class.hpp The class accepts a allocator and indeed uses it to instantiate the std::string inside. But there are two vectors inside - std::vector<format_item_t> items_; // each '%..' directive leads to a format_item std::vector<bool> bound_; // stores which arguments were bound. size() == 0 || num_args I am seeing that the vectors are not using the allocators. Is this the intended behavior? Is it right, to try to make an application not to use the normal new/delete completely? Thanks, Gokul.

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Exception: adding diagnostic information from a dtor?
by Michael Schuerig 16 Jun '11

16 Jun '11

The FAQ for boost exception contain this example snippet for adding further information to an exception while the call stack is unwound catch( boost::exception & e ) { e << foo_info(foo); throw; //Okay, re-throwing the original exception object. } I like that this possible, but I think the resulting code is somewhat tedious: void foo(const string& file_name) { try { do_something_fallible(file_name); } catch( boost::exception & e ) { e << boost::errinfo_file_name(file_name); throw; } } I'd rather write it like this: void foo(const string& file_name) { diagnostic<errinfo_file_name>(file_name); do_something_fallible(file_name); } My first, non-generic attempt fails: class diagnostic { public: explicit diagnostic(const string& file_name) : file_name_(file_name) {} ~diagnostic() { if ( boost::exception_ptr e = boost::current_exception() ) { *e << boost::errinfo_file_name(file_name_.c_str()); } } private: const string file_name_; }; The requirements for boost::current_exception() state that it may only be called inside a catch block, therefore the code above is illegal to begin with. Ignoring that, operator<< doesn't appear to be suitably overloaded for this use, anyway. Now, I'm wondering, is what I'm trying to achieve a bad idea? If not, is there another way to do it? Michael -- Michael Schuerig mailto:michael@schuerig.de http://www.schuerig.de/michael/

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[linking] simplifying compilation line with many boost libs
by alfC 16 Jun '11

16 Jun '11

This post is mainly about the linux distribution of boost, oriented to gcc. Given the lack of pgk-config for linux and the lack of linking pragmas in g++ I am wondering if somebody investigated the possibility of having all boost binary libraries in one file or something like that. Such that compilation line c++ -lboost_regex -lboost_system -lboost_filesystem -lboost_mpi - lboost_serialization ... can be simplified into c++ -lboost_all or simply c++ -lboost where boost_all.so have the contents of all boost libraries or references to the other boost_*.so the idea is to simplify sharing short code with other people not familiar with boost itself. Thanks, Alfredo

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[filesystem]
by Ford Sleeman 15 Jun '11

15 Jun '11

Hi everybody, I am trying to use the Boost filesystem library and ran into a strange problem. When I include the library in a project (automake or standard Makefile) I can link everything and the resulting program runs fine. I get errors like this for even including the <boost/filesystem.hpp> file in a second source or header file: [my path]/boost/exception/exception.hpp:179: error: expected identifier before numeric constant [my path]/boost_1_46_1/boost/exception/exception.hpp:179: error: expected `>' before numeric constant [my path]/boost_1_46_1/boost/exception/exception.hpp:180: error: expected unqualified-id before numeric constant [my path]/boost_1_46_1/boost/exception/exception.hpp:182: error: expected identifier before numeric constant [my path]/boost_1_46_1/boost/exception/exception.hpp:182: error: expected `>' before numeric constant [my path]/boost_1_46_1/boost/exception/exception.hpp:183: error: expected unqualified-id before numeric constant [my path]/boost_1_46_1/boost/exception/exception.hpp:185: error: expected identifier before numeric constant I could not find any examples of linking multiple files in a project with the library, does such exist? Is there something special to include the headers in this situation? If I comment out the #include and any references to the boost::filesystem functions in the second source file the program will compile correctly. Thanks, Ford Sleeman NOTE: The information contained in this message may be privileged and confidential and protected from disclosure. If the reader of this message is not the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by replying to the message and deleting it from your computer. -------------------------------------- VCU Health System http://www.vcuhealth.org

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[math/distributions] Problem using inv-chi**2 and quantiles
by Paul Johnson 15 Jun '11

15 Jun '11

I'm trying to duplicate Excel's CHIINV to calculate confidence limits for an observed number of events. I think I'm nearly there, largely as a result of trial and error, but the boost results still significantly differ from the Excel results, so I've presumably messed up somewhere. Any advice will be *greatly* appreciated. The Excel formulas I'm using are: lo limit = CHIINV((1+$C$3)/2, 2*B6)/2 hi limit = CHIINV((1-$C$3)/2, 2*(B6+1))/2 where $C$3 is the confidence level required (95%), and B6 is the number of events observed. In Excel, 'CHIINV' is documented as: > CHIINV(probability,degrees_freedom) > Probability is a probability associated with the chi-squared distribution. > Degrees_freedom is the number of degrees of freedom. For 17 events, for example, Excel is producing limits of [9.90, 27.22]. I've attached my complete boost test program below, which I hope does the same thing, but there was a large amount of guesswork here. This program produces results of [10.67, 25.98] for 17 events. Can anyone tell me what I'm doing wrong? Thanks - Paul

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[msm] EUML submachine without macro
by rayg 15 Jun '11

15 Jun '11

Hi, I'm trying to define a submachine without the BOOST_MSM_EUML_DECLARE_STATE_MACHINE macro (the "old" way - like in http://www.boost.org/doc/libs/1_46_0/libs/msm/doc/HTML/examples/SimpleTutor…) The "main" machine works as expected. However, the submachine doesn't kick in at all (the system asserts in default no-transition handler). Any ideas? Ray ------------ #include <boost/msm/front/state_machine_def.hpp> #include <boost/msm/front/euml/euml.hpp> #include <boost/msm/back/state_machine.hpp> using namespace std; using namespace boost::msm::front::euml; namespace msm = boost::msm; //#define WITH_MACROS //************ //* Events //************ BOOST_MSM_EUML_EVENT(play) BOOST_MSM_EUML_EVENT(toggle) //************* //* Submachine //************* #ifdef WITH_MACROS //************************ //* This works fine //************************ BOOST_MSM_EUML_ACTION(Song1_Entry) { template <class Event,class FSM,class STATE> void operator()(Event const&,FSM&,STATE& ) { // Called as expected std::cout << "entering: Song1" << std::endl; } }; BOOST_MSM_EUML_STATE((Song1_Entry), Song1) BOOST_MSM_EUML_STATE((), Song2) BOOST_MSM_EUML_TRANSITION_TABLE(( Song2 == Song1 + toggle, Song1 == Song2 + toggle ), sub_transition_table) BOOST_MSM_EUML_DECLARE_STATE_MACHINE((sub_transition_table, init_ << Song1), _Playing) #else //************************ //* Doesn't work //************************ struct Song1_impl : public msm::front::state<> , public msm::front::euml::euml_state<Song1_impl> { template <typename EVENT, typename FSM> void on_entry(EVENT const&, FSM& fsm) { // Not called std::cout << "entering: Song1" << std::endl; } }; struct Song2_impl : public msm::front::state<> , public msm::front::euml::euml_state<Song2_impl> { }; Song1_impl const Song1; Song2_impl const Song2; struct _Playing : public msm::front::state_machine_def< _Playing > { // Initial state typedef Song1_impl initial_state; BOOST_MSM_EUML_DECLARE_TRANSITION_TABLE(( Song2 == Song1 + toggle, Song1 == Song2 + toggle ), sub_transition_table) }; #endif // Pick a back-end typedef msm::back::state_machine<_Playing> Playing_impl; Playing_impl const Playing; //********************************** //* Main machine //********************************** struct Empty_impl : public msm::front::state<> , public msm::front::euml::euml_state<Empty_impl> { }; Empty_impl const Empty; struct _Player : public msm::front::state_machine_def< _Player > { // Initial state typedef Empty_impl initial_state; BOOST_MSM_EUML_DECLARE_TRANSITION_TABLE(( Playing == Empty + play ), transition_table) }; // Pick a back-end typedef msm::back::state_machine<_Player> player; int main(int argc, char* argv[]) { player p; p.start(); p.process_event( play ); return 0; } -- View this message in context: http://boost.2283326.n4.nabble.com/msm-EUML-submachine-without-macro-tp3598… Sent from the Boost - Users mailing list archive at Nabble.com.

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reference_wrapper 101
by Robert Jones 15 Jun '11

15 Jun '11

I thought understood what boost::reference_wrapper was all about, and in the context of, say Boost.Bind, it seems pretty clear. But why would you define a function to RETURN a reference_wrapper? eg template <class T> struct X { std::pair<boost::reference_wrapper<T>, unsigned> getSomething(....) const; }; I suspect I'm having a 'doh' moment here! Thx, - Rob.

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