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[Boost.MPL] mpl::find<Types, T> not allowed in with T as template<typename T> argument?
by Manuel Jung 26 Jun '07

26 Jun '07

Hi, I have a short question. ----------- typedef boost::mpl::vector<double, int> Types; template<typename T> void send(){ typedef boost::mpl::find<Types, T>::type iter_T; //Doesn't compile typedef boost::mpl::find<Types, int>::type iter_T_static; //Compiles } ------------ I want the first cersion with my own Template Type. But the compiler gives me somthing like "Not enough Template arguments". (My Compiler outputs me german error messages...) Am i not allowed using my own template arguments with boost::mpl::find? Or what do i have to change? Thanks! Manuel Jung

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how do I use boost::iostreams::code_converter with GNU codecvt<.., ..., __gnu_cxx::encoding_state>?
by 宋浩 26 Jun '07

26 Jun '07

the GNU libstdc++ offers a flexible character encoding convertion primitive (essentially a wrapper for the iconv C API), but in a non-standard partial specialization of codecvt. for example, if I want to use this codecvt, to convert between internal encoding UCS-4LE and external encoding GB18030 (which is China's national standard for Chinese character encoding), I will write // define the codecvt type typedef std::codecvt<wchar_t, char, __gnu_cxx::encoding_state> w_codecvt; // define a std::locale instance only for codecvt purpose std::locale loc(std::locale::classic(), new w_codecvt); const w_codecvt &cvt = std::use_facet<w_codecvt>(loc); // the internal/external character encoding is specified as the // argument to the constructor of __gnu_cxx::encoding_state w_codecvt::state_type state("UCS-4LE", "GB18030"); // use cvt and state cvt.in(state, ...); the problem is, if I want to use this codecvt<.., .., __gnu_cxx::encoding_state> with code_converter, I can't find a way to tell code_convert the encoding names (UCS-4LE, GB18030), seems that code_converter will always use the default constructor of Codecvt::state_type. And if I specify the Codecvt template argument of code_converter to codecvt<.., .., encoding_state>, imbue() will become a no-op, which makes things even worse. BTW: the documentation for GNU libstdc++ codecvt is available here http://gcc.gnu.org/onlinedocs/libstdc++/22_locale/codecvt.html

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wrt my last post with (No Subject)
by jono 26 Jun '07

26 Jun '07

i've solved the problem, thanks. it was me. sorry about the missing subject line. jono

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(no subject)
by jono 26 Jun '07

26 Jun '07

hi all. i'm using boost::state_chart in a serial protocol handler. i have some code that collects characters in each state object by calling Protocol::input(byte) on the state machine, which then dispatches events in response to control bytes and for all other bytes, calls ICharacterInput .... . . state_cast< const ICharacterInput & >().input(c); . . ... which stores the new character in the base class ICharacterInput. i then process the stored characters in the the state's destructor. i've used very similar boost code in a number of protocol handlers and it works great. ...but.. this handler intermittently throws exceptions in boost/statechart/simple_state.hpp when it tries to downcast and delete a pointer to the state. does anybody have any suggestions where i should look to see what's going on? in particular, is the downcast/delete sequence going to be calling any code in my own base class destructors? the destructor in which the exception is thrown (and caught) seems to complete its own instructions without problems. this protocol only uses the EvStartOfHeader and EvEndOfText events. cheers jono poff ==================================================== ==================================================== ===================================== my header file ... struct EvStartOfHeader : sc::event< EvStartOfHeader > {}; struct EvStartOfText : sc::event< EvStartOfText > {}; struct EvEndOfText : sc::event< EvEndOfText > {}; struct EvEndOfTransmission : sc::event< EvEndOfTransmission > {}; struct EvReset : sc::event< EvReset > {}; struct Waiting; struct Decoding; struct Reset; struct RcvHeader; struct RcvText; struct Protocol: sc::state_machine< Protocol, Waiting > , IProtocol { Protocol(); ~Protocol(); virtual const char **input(byte c); }; struct Waiting : ICharacterInput, sc::state< Waiting, Protocol> { Waiting( my_context ctx ); ~Waiting(); typedef sc::transition< EvStartOfHeader, Decoding > reactions; }; struct Decoding: ICharacterInput, sc::state< Decoding, Protocol, RcvText> { Decoding( my_context ctx ); ~Decoding(); typedef sc::transition< EvReset, Waiting > reactions; }; struct RcvHeader : ICharacterInput, sc::state< RcvHeader, Decoding> { RcvHeader( my_context ctx ); ~RcvHeader(); typedef sc::transition< EvStartOfText, RcvText > reactions; }; struct RcvText : ICharacterInput, sc::state< RcvText, Decoding> { RcvText( my_context ctx ); ~RcvText(); typedef sc::transition< EvEndOfText, Waiting > reactions; }; ======================================================= ======================================================= ======================================================= ======================================================= ======== so what happens is: ======== in my dispatch code ... . . case ETX:// End of Text process_event( EvEndOfText() ); . . ======== results in ... . . =========================================== =========================================== == in boost/statechart/simple_state.hpp ... ======== ======== ======== a call to simple_state::exit_impl() {...} ======== results in call to .... . . intrusive_ptr & operator=(T * rhs) { this_type(rhs).swap(*this); return *this; } . . ======== with rhs == 0 ======== then delete throws here ... . . . template< class MostDerived, class Context, class InnerInitial, history_mode historyMode > inline void intrusive_ptr_release( const ::boost::statechart::simple_state< MostDerived, Context, InnerInitial, historyMode > * pBase ) { if ( pBase->release() ) { // The cast is necessary because the simple_state destructor is non- // virtual (and inaccessible from this context) delete polymorphic_downcast< const MostDerived * >( pBase ); } } . . . ============================ ============================ ============================ ============================

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[asio] Any IsConnected() method?
by Sunsawe 25 Jun '07

25 Jun '07

Hi, I would just like to know if there is a simple way to check wether or not a socket is still connected or not. And for a ssl socket? Thanks -- View this message in context: http://www.nabble.com/-asio--Any-IsConnected%28%29-method--tf3978649.html#a… Sent from the Boost - Users mailing list archive at Nabble.com.

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[asio] Assertion failed at run time
by Sawe Sun 25 Jun '07

25 Jun '07

Hi,I'm new to boost and asio. I'm trying to use the ssl support of asio in a simple client.This is the code that i'm using to connect to the server: boost::asio::io_service io_service; boost::asio::ssl::context * ctx; boost::asio::ssl::stream<boost::asio::ip::tcp::socket> * socket; boost::asio::error Error; boost::asio::ip::tcp::resolver resolver(io_service); boost::asio::ip::tcp::resolver::query query(boost::asio::ip::tcp::v4(),hostname,port ); boost::asio::ip::tcp::resolver::iterator endpoint_iterator = resolver.resolve(query,boost::asio::assign_error(Error)); boost::asio::ip::tcp::resolver::iterator end; if(Error) return false; ctx = new boost::asio::ssl::context(io_service, boost::asio::ssl::context::sslv23); boost::asio::ip::tcp::endpoint endpoint = *endpoint_iterator; socket = new boost::asio::ssl::stream<boost::asio::ip::tcp::socket>(io_service,*ctx); Error = boost::asio::error::host_not_found; while (Error && endpoint_iterator != end) { socket->lowest_layer().close(); socket->lowest_layer().connect(endpoint,boost::asio::assign_error(Error)); } if (Error) return false; socket->handshake(boost::asio::ssl::stream_base::client,boost::asio::assign_error(Error)); if (Error) return false; else return true;That compiles fine but at run time i have this assertion exception:Assertion failed!Program:... //it is written like thatFile: (PATH)\boost-1_33_1\...\shared_ptr.hLine: 253Expression: px != 0I'm using vs2005. i can't see what is happening because evenif i'm using the "Step Into new Instance" mode to run the program in debug mode, the exception is fired before any step. This is the call stack: msvcr80d.dll!_wassert(const wchar_t * expr=0x0093888c, const wchar_t * filename=0x009388a0, unsigned int lineno=253) Line 384 C CTest.exe!boost::shared_ptr<boost::asio::ssl::detail::openssl_init<1>::do_init>::operator->() Line 253 + 0x1f bytes C++ CTest.exe!boost::asio::ssl::detail::openssl_init<1>::do_init::openssl_locking_func(int mode=5, int n=16, const char * file=0x009401dc, int line=271) Line 83 + 0x37 bytes C++ CTest.exe!_CRYPTO_lock() + 0x81 bytes C CTest.exe!_ssl_load_ciphers() + 0x113 bytes C CTest.exe!_SSL_COMP_get_compression_methods() + 0x5 bytes C CTest.exe!_SSL_library_init() + 0x129 bytes C CTest.exe!boost::asio::ssl::detail::openssl_init<1>::do_init::do_init() Line 57 C++ CTest.exe!boost::asio::ssl::detail::openssl_init<1>::do_init::instance() Line 74 + 0x4a bytes C++ CTest.exe!boost::asio::ssl::detail::openssl_init<1>::openssl_init<1>() Line 96 + 0x5a bytes C++ CTest.exe!`dynamic initializer for 'boost::asio::ssl::detail::openssl_init<1>::instance_''() Line 69 + 0x28 bytes C++ msvcr80d.dll!_initterm(void (void)* * pfbegin=0x00937234, void (void)* * pfend=0x00937f0c) Line 855 C CTest.exe!__tmainCRTStartup() Line 501 + 0xf bytes C CTest.exe!WinMainCRTStartup() Line 403 C kernel32.dll!7c816ff7() [Frames below may be incorrect and/or missing, no symbols loaded for kernel32.dll] CTest.exe!boost::asio::ip::basic_endpoint<boost::asio::ip::tcp>::basic_endpoint<boost::asio::ip::tcp>(const boost::asio::ip::address & addr={...}, unsigned short port_num=111) Line 155 + 0x21 bytes C++ CTest.exe!boost::asio::ip::basic_endpoint<boost::asio::ip::tcp>::basic_endpoint<boost::asio::ip::tcp>(const boost::asio::ip::address & addr={...}, unsigned short port_num=115) Line 155 + 0x21 bytes C++ CTest.exe!boost::asio::ip::basic_endpoint<boost::asio::ip::tcp>::basic_endpoint<boost::asio::ip::tcp>(const boost::asio::ip::address & addr={...}, unsigned short port_num=111) Line 155 + 0x42 bytes C++ CTest.exe!boost::asio::ip::basic_endpoint<boost::asio::ip::tcp>::basic_endpoint<boost::asio::ip::tcp>(const boost::asio::ip::address & addr={...}, unsigned short port_num=54) Line 155 + 0x21 bytes C++ CTest.exe!wxFileName::Assign(const wxFileName & filepath={...}) Line 310 C++ CTest.exe!boost::asio::ip::basic_endpoint<boost::asio::ip::tcp>::basic_endpoint<boost::asio::ip::tcp>(const boost::asio::ip::address & addr={...}, unsigned short port_num=111) Line 155 + 0x42 bytes C++ CTest.exe!boost::asio::ip::basic_endpoint<boost::asio::ip::tcp>::basic_endpoint<boost::asio::ip::tcp>(const boost::asio::ip::address & addr={...}, unsigned short port_num=54) Line 155 + 0x21 bytes C++ CTest.exe!wxFileName::Assign(const wxFileName & filepath={...}) Line 310 C++ CTest.exe!boost::asio::ip::basic_endpoint<boost::asio::ip::tcp>::basic_endpoint<boost::asio::ip::tcp>(const boost::asio::ip::address & addr={...}, unsigned short port_num=57) Line 155 + 0x42 bytes C++ CTest.exe!_RSA_padding_check_PKCS1_type_1() + 0xf2 bytes C CTest.exe!boost::asio::ip::basic_endpoint<boost::asio::ip::tcp>::basic_endpoint<boost::asio::ip::tcp>(const boost::asio::ip::address & addr={...}, unsigned short port_num=897) Line 155 + 0x21 bytes C++ 02840448() dbghelp.dll!03020004() Can somebody tell me what i'm doing wrong?Thanks _________________________________________________________________ David Guetta a réuni les sons les plus connus de Messenger dans le Mix Messenger, le son de l’été ! Téléchargez-le gratuitement ! http://specials.divertissements.fr.msn.com/mixmessenger

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[program_options] bad_any_cast problem with strings in variables_map
by Jeffrey Schmidt 25 Jun '07

25 Jun '07

(apologies if this comes through multiple times, I'm having subscription issues) I'm a novice Boost user attempting to use program_options. As far as I can tell from the docs and sample code, this should work (only relevant code included): po::options_description desc("Allowed options"); desc.add_options() ("client", po::value<string>(), "set client name") ("test", "tool test mode, dump command line options only") ; po::variables_map vm; po::store(po::parse_command_line(ac, av, desc), vm); po::notify(vm); if (vm.count("test")) { if (vm.count("client")) cout << "client set to " << vm["client"].as<string>() << "\n"; else cout << "client not set\n"; } However, when I run with "--client testclient --test", the as<string> call generates a bad_any_cast exception. What am I missing or misunderstanding? -- Jeffrey Schmidt, senior software architect MultiAd(r) Creator and Creator Server jschmidt(a)multiad.com

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Question
by question boost 25 Jun '07

25 Jun '07

Hi, using Code Blocks i get the folowing message. ld.exe "Cannot find -lboost_filesystem-mgw-mt-s-l_33_l" How and where can I get this file? Thank You _________________________________________________________________ David Guetta a réuni les sons les plus connus de Messenger dans le Mix Messenger, le son de l’été ! Téléchargez-le gratuitement ! http://specials.divertissements.fr.msn.com/mixmessenger

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Sunpro CC 5.8, -library=stlport4, multi_index, one last time
by Benson Margulies 25 Jun '07

25 Jun '07

I beg the indulgence of the maintainers to clarify the support intentions here and then I'll go back to my cave. The facts are: 1) The regression tests run reasonably on CC 5.8, with or without -library=stlport4 2) I have a seemingly simple example of using multi_index that won't compile with CC 5.8 unless I'm using -library=stlport4. The compile error, for what it's worth, does not point to one of the weaknesses of the 'old Sun STL' in any obvious way. But it could easily be that some ifdef that is trying to compensate for the old STL is in turn creating the conditions for the failure. (I'm not entirely sure about #1.) The question is: "Is it the intention of the maintainers to support CC 5.8 without -library=stlport4?" If the answer is 'yes', then I will nudge to get this case included in the regression, and I will invest some time in trying to unscrew the inscrutable error. If the answer is 'no', then I will concentrate on moving our Apatosaurus of a code-base to getting itself compiled with -library=stlport4 as soon as I can, and defer use of boost until that can accomplish itself.

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tokenizer
by david bautista garcia 25 Jun '07

25 Jun '07

Hello: somebody can say me that it makes this code, mainly the option : sep (: , "", boost:: keep_empty_tokens) typedef boost::tokenizer<boost::char_separator<char> > tokenizer; boost::char_separator<char> sep(":", "", boost::keep_empty_tokens); tokenizer tokens(str, sep); tokenizer::iterator tok_iter = tokens.begin(); //cout << "TOKEN " << (*tok_iter) << endl; the input is: BSIC=4-6,BCCHFREQ=784,SYSID=DCS1800,MSTXPMAXGSM=<NULL>,MSTXPMAXDCS=0,MSTXPMAXPCS=<NULL>,CELLGLID="214"-"03"-6004-1519,RACODE=137,RACOL=0,GRXLAMI=6,GMSTXPMAC=15; What's de output? Thanks -------------------------------------------------------------------------------------------- ¿Ya sabes con quién vas? ¿Héroe o Villano? Prepárate para la batalla final en http://friki.ozu.es -------------------------------------------------------------------------------------------- Correo enviado desde http://www.ozu.es

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[Preprocessor] Expand to nothin - BOOST_PP_SEQ_PUSH_BACK
by Manuel Jung 24 Jun '07

24 Jun '07

Hi The BOOST_PP_SEQ_PUSH_BACK Macro expands to the seq with the extra element. But i don't want it to expand. I want to use the sequence later instead. How can i supress the expanding? I looked through the docs, but didn't find the right clue. I'm new too Preprocessorprogramming, so please excuse, if my question is stupid. Not the easiest thing, starting Preprocessor and Metaprogramming from nothing but the docs. Kind Regards Manuel Jung

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Boost.graph : 3D graphics primitives hierarchy (scenegraph)
by Nicholas Yue 23 Jun '07

23 Jun '07

Hi, I am considering using boost::graph to represent a DAG of 3D graphics primitive hierarchy, much like a scenegraph in games with the exception that no drawing code is embedded with this structure. The DAG is important in that I will be injecting changes to certain nodes which than affects/updates all it's child nodes. The intention is to allow me to write tools to work with this hierarchy. Eventually, these geometries may be turned into renderable entities (via some visitor iterator) for visualization/verification but that is not the main purpose. I am very new to boost::graph and hope someone can point me at information or open source project that is relevant to my exploration. Regards

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Dijkstra Visitor - Accessing the priority queue
by Jonas Gabriel 23 Jun '07

23 Jun '07

Good morning, I'm trying to make a single pair shortest path function using the goal-directed search technique based on dijkstra_shortest_paths and Visitors. In some point when the target vertex is processed, I would like to exit dijkstra_shortest_paths.To do that I 'm thinking trying to empty the priority queue. Can I access the priority queue inside a visitor using something like an extern declaration, since none of the Dijkstra Visitor's methods gets the priority queue as an argument ? With regards, Jonas Gabriel

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How to "splice" function arguments?
by Zeljko Vrba 23 Jun '07

23 Jun '07

I have the following situation with parallel overloaded functions: void f(X *x) | void f(int g, X *x) { { | { Impl<false>::f(-1, x); | Impl<true>::f(g, x); } | } template<bool F> struct Impl { typedef Detail<F> detail; void f(int g, X *x) { // CODE X *t = detail::smth(g, x); // CODE } }; In the "false" case, the argument g of Impl::f is not used and I want to get rid of it in compile-time as an optimization. The rest of the CODE is completely identical. In other words, I want to transform the "false" case, at compile-time, to the following: void f(X *x) { Impl<false>::f(x); } template<> struct Impl<false> { typedef Detail<false> detail; void f(X *x) { // CODE X *t = detail::smth(x); // CODE } }; Now, I could manually duplicate all of the code in Impl::f(int, X*) into Impl::f(X*) and remove the extra argument in the call to detail::smth. Doing such specialization manually seems _very_ inelegant and error-prone (I'm not really a fan of copy-pasting the code :)) Is there a better way; ie. doing it automatically? If so, how? It is acceptable to manually overload the top-level f() function, as it has no other code except the dispatch to Impl::f. I want full compile-time solution; ie. I do not want the stack space for the unneeded integer parameter ever to be allocated. [The code for the "false" case will be called on every function invocation, so YES, performance DOES matter even without apriori profiling.] Signatures in the implementation of Impl and Detail are flexible and I can change them if it helps solving the problem. The only thing that I do not want to change are the signatures of top-level f() function overloads. Thanks, Zeljko.

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[boost.test] Provoking a core-dump
by Zeljko Vrba 23 Jun '07

23 Jun '07

I'm using the boost minimal testing facility - mostly because I do not want to build full boost. [I spent one day about an hour trying to figure out how to build a 64-bit version on Solaris with SunCC and failed. So I gave up. Besides, minimal testing facility is enough for me.] Is it possible to configure BOOST_CHECK or BOOST_REQUIRE to behave as assert? BOOST_REQUIRE throws an exception which eventually gets caught and the test just prints "failed". That's not what I want. I want that the message is printed and abort() immediately called so that I can inspect the core-dump and debug the problem. A quick&dirty fix is to add something like the following on top of each test: #ifdef BTEST_OVERRIDE #define BOOST_REQUIRE assert #define BOOST_CHECK assert #endif Is there another possibility? Ideally, there would be a command-line switch to toggle this behaviour at runtime. So the first run of tests in "normal" mode just gives a quick overview of everything, and another "diagnostic" mode (running with a hypothetical "-abort" switch) calls abort() as soon as any CHECK or REQUIRE fails.

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Boost test thread safety
by Chris 23 Jun '07

23 Jun '07

I have been working for a while on trying to diagnose whether my library or the boost test library is causing many of my thread issues. I hear that the boost test is not thread safe, is the correct? How incomplete is the thread safety and is there a time span on when it will be achieved? -Thanks for the current thread Chris

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Boost.Test internal framework error: unknown reason
by Ole Christian Weidner 23 Jun '07

23 Jun '07

Aloha, I have a strange problem when running the Boost Unit Test Framework on MacOS X (Intel). I'm using Boost 1.33.1 built from source with gcc 4.0.1 (Apple Computer, Inc. build 5367). Compiling and linking of my tests works fine with: /usr/bin/g++-4.0 -arch i386 -Wl,-all_load -L$BOOST_LOCATION - lboost_unit_test_framework ... but whenever I try to run my test application I get a not very meaningful error message (the same code works fine on Linux and Windows): [Session started at 2007-06-11 13:06:27 -0500.] SAGA C++ Conformance Tests Boost.Test internal framework error: unknown reason saga_test_suite_v2 has exited with status 200. The error seems to occur somewhere within the framework initialization - the entry point (test_suite * init_unit_test_suite (int argc, char* argv[])) is never reached. Any ideas how to track down the error? Are there any command line arguments to make the framework's output more verbose? Thanks, Ole

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[1.34.1] Release Candidate
by Thomas Witt 23 Jun '07

23 Jun '07

Hi, The 1.34.1 release candidate is now available from http://www.boost.org/release/ please give it a try and report any problems to the developer list or directly to me. I'll be travelling till July 5th. Internet access is unlikely, so far :( Thanks Thomas -- Thomas Witt witt(a)acm.org

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problem... maybe boost could help
by Lukasz 22 Jun '07

22 Jun '07

Hello, I'm fairly new to boost and don't know all of the functionality. I have been using the serialization library, read about mpl, signals and that's about it. Maybe someone will have an idea if there is anything in boost that i could use to solve the following problem (or any other solution). I'm working a an Agent framework, and at this point, specifically on an event (messaging system). The basic layout is the following (what concerns the messaging part): The framework contains Agents and Behaviors. They all need to communicate with each other. Both of these classes derive from an interface EventReceiver, which declares, amongst other things, a pure virtual ProcessEvent(Event * event) function. Specific behaviors and agents are obviously derived from the base ones. All events are derived from the base Event class (to allow users to create their own events with whatever information they need in there). The main messaging hub is a class MessengerService, which contains two maps, the first one relates static UUID's of events to UUID's of receivers , and the second receiver UUID's with a list of actual events of type Event*. The basic use case is: a behavior calls a register function in MessengerService to add itself as a receiver for a certain type of event (register/unregister can happen at anytime). At anytime, a behavior/agent can create an event, and call a send function, which adds it to the list of events that are pending for a given receiver (if a receiver was registered for this event type). As all agents/behaviors are ticked, a "Monitor" is moved to the current agent/behavior. The monitor queries the messenger service for all pending events destined for the current agent/behavior, and calls a processEvent function on the agent/behavior passing it the event as an argument. The problem is here. I want agents/behaviors to add handlers for different event types that they registered for, i.e. class SomeBehavior: public Behavior { ... processEvent(EventTest1 & event); processEvent(EventTest2 & event); ... } Since the events were registered, i know that the correct handlers exist in the most derived class types (there will also be a forwarding scheme for unregistered or broadcast events). The problem is that i only have a pointer to the base class (EventReceiver) and to the base class of the event (Event). I can't cast directly because i don't know the type to cast to. Also, i don't want to add virtual functions for all possible events to the base class, because that would mean that users would have to play around in the base class (framework) every time they add a new event. Lastly, i wanted to avoid having a general processEvent(Event & event) function and then have the users "switch" on the event type. I solved part of the problem (the first half) by adding a "MostDerviedHelper", which looks sort of like this: template<class Derived> class MostDerivedHelper { .... void dispatchEvent(Event * event) { // Do dispatching here m_derivedPointer->processEvent(*(event->This())); } private: Derived * m_derivedPointer; } Each derived type has a helper, which obviously contains the correct most derived type (since it's itself). The problem now, is that i don't know what to cast the event to so that it calls the correct handler. I can't add the same type of helper to event, because then i would have to pass it the receiver derived type through a template, but since it would have to be a template, i can't call it using my base class event pointer (can't create templated virtual functions). I tried adding a virtual function called "This()" to all events, which would return the derived classes' this pointer, but eventhough it's the correct type, i still need to cast it (which i can't) since it has to be resolved at compile time. I read quite a few things about double/multiple dispatch (in Loki for example), but it's not quite the solution i'm looking for because a usual implementation uses a callback, and that would require that i make my handlers static. MPL is not much of a help either because it's based on static polymorphism, and what i actually need is dynamic. I thought of using boost function & boost bind combined with a double dispatch scheme, but this doesn't work either because then i can't serialize it (i could re-perform the binding after a restore, which i already do for boost::signals, but it's a hassle). So, i'm pretty much out of ideas. I think to sum it up, what i would sort of need is: template<class ReceiverType, class EventType> class Dispatcher { ... send(ReceiverType * receiver, eventType * event) { receiver->processEvent(event); } } In this situation, i would already have all the correct types. The problem is that i can't get all this info at the same time. I also thought about using the curiously recurring template pattern as such: template<class Derived> class Event { template<class derivedReceiver> dispatch(derivedReceiver, Derived event) { .... } } This would work, except that since all events now must specialize to some type of base, i can't use a base class pointer to store in my map, i.e. i can't store all of my events in a map. If anyone has some brilliant idea as to how this can be done (if it can), then i would appreciate the input. Thanks, Lukasz -- View this message in context: http://www.nabble.com/problem...-maybe-boost-could-help-tf3959613.html#a112… Sent from the Boost - Users mailing list archive at Nabble.com.

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[wave] preprocessing error
by Ovanes Markarian 22 Jun '07

22 Jun '07

Hello Hartmut, I have a question to you. I got a header file with an error. The content of a file looks like: #ifndef SOME_GUARD #define SOME_GUARD ... some content #endif SOME_GUARD As you see #endif SOME_GUARD is wrong, standard defines that #endif is followed by a newline. Unfortunately wave threw an exception. Calling what member on the std::exception instance caught resulted in the string: boost::wave::preprocess_exception I spent some time to search where that happened and which line was guilty. Is there any way for you to write the file and line which caused the error? I assume smth bad happens inside the wave lib, since I even can not compare curren and end iterator tokens. With Kind Regards, Ovanes Markarian

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ASIO: multiple threads, single io_service
by Andrej van der Zee 22 Jun '07

22 Jun '07

Hi, I have some (beginners) question about the example server3-porgram that ships with the library. It uses multiple threads with a single io_service. In the method server::run() this happens: std::vector<boost::shared_ptr<boost::thread> > threads; for (std::size_t i = 0; i < thread_pool_size_; ++i) { boost::shared_ptr<boost::thread> thread(new boost::thread(boost::bind(&boost::asio::io_service::run, &io_service_))); threads.push_back(thread); } for (std::size_t i = 0; i < threads.size(); ++i) threads[i]->join(); But when are the threads actually scheduled? Does this happen by the shared io_service? Are the registered callback methods for async_read, async_accept, etc executed in the threads? Also, are there any tradeoffs that I should know off for using the single io_service vs io_service-per-thread approach? Thank you, Andrej ___________________________________________________________ Yahoo! Mail is the world's favourite email. Don't settle for less, sign up for your free account today http://uk.rd.yahoo.com/evt=44106/*http://uk.docs.yahoo.com/mail/winter07.ht…

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[ptr_container] How to transfer ownership from smart_ptr to ptr_container
by Seweryn Habdank-Wojewódzki 22 Jun '07

22 Jun '07

Hi! Is there any smart_ptr and ptr_container that can transfer ownership of pointer, to avoid useless copy-construction and destruction of the object. More less scenario can be like that. 1. smart pointer handles pointer to the huge data. 2. pointer is transfered via signal to the object that has queue of them. 2a. remark not all object are going to the queue, so there is a need to keep them in smart pointer. 3. Queue sends away pointer, or internally destroys (respectively to demand of another signal in the program. More less the simplified draft is shown below. Maybe I have to use vector <shared_ptr <T> > instead of ptr_container? Best regards. #include <boost/ptr_container/ptr_vector.hpp> #include <boost/shared_ptr.hpp> #include <iostream> class Foo { public: Foo (int const i) : i_ (i), j_() { ++counter; ++crcounter; std::cout << "Foo (int)" << '\t'; print_counter(); } Foo (Foo const & f) : i_ (f.i_), j_() { ++counter; ++crcounter; std::cout << "Foo (Foo)" << '\t'; print_counter(); } ~Foo() { --counter; std::cout << "~Foo () " << '\t'; print_counter(); } void print (std::ostream & os) const { os << i_; } static int counter; static int crcounter; static void print_counter() { std::cout << "No. Foo = " << counter << " No. created = " << crcounter << '\n'; } private: int i_; int j_[10000]; }; int Foo::counter = 0; int Foo::crcounter = 0; std::ostream & operator<< (std::ostream & os, Foo const & f) { f.print (os); return os; } int main() { using namespace boost; using std::cout; ptr_vector<Foo> pvf; Foo * pf = new Foo(7); cout << *pf << '\n'; pvf.push_back (pf); pf = new Foo(9); cout << *pf << '\n'; pvf.push_back (pf); shared_ptr<Foo> spf (new Foo(11)); cout << *spf << '\n'; pvf.push_back (new Foo (*spf)); spf = shared_ptr <Foo> (new Foo(13)); cout << *spf << '\n'; pvf.push_back (new Foo (*spf)); cout << pvf[0] << '\n'; cout << pvf[1] << '\n'; cout << pvf[2] << '\n'; cout << pvf[3] << '\n'; pf = new Foo(pvf[0]); pvf.erase(pvf.begin()); cout << *pf << '\n'; spf = shared_ptr <Foo> (new Foo (pvf[2])); cout << *spf << '\n'; delete pf; } -- |\/\/| Seweryn Habdank-Wojewódzki \/\/

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(no subject)
by david bautista garcia 22 Jun '07

22 Jun '07

hello: I don't understand this code, anybody can explain to me what does ":" and "" typedef boost::tokenizer<boost::char_separator<char> > tokenizer; boost::char_separator<char> sep(":", "", boost::keep_empty_tokens); tokenizer tokens(str, sep); tokenizer::iterator tok_iter = tokens.begin(); //cout << "TOKEN " << (*tok_iter) << endl; if de input is : TGTBTS:NAME=TGTBTS:42,BSIC=4-6,BCCHFREQ=784,SYSID=DCS1800,MSTXPMAXGSM=<NULL>,MSTXPMAXDCS=0,MSTXPMAXPCS=<NULL>,CELLGLID="214"-"03"-6004-1519; TGTPTPPKF:NAME=TGTBTS:42/TGTPTPPKF:0,RACODE=137,RACOL=0,GRXLAMI=6,GMSTXPMAC=15; what's de output? thanks -------------------------------------------------------------------------------------------- ¿Ya sabes con quién vas? ¿Héroe o Villano? Prepárate para la batalla final en http://friki.ozu.es -------------------------------------------------------------------------------------------- Correo enviado desde http://www.ozu.es

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Need help understanding boost::operators::dividable
by Scott, Steven 22 Jun '07

22 Jun '07

I'm sure the answer to this is out there somewhere, but I'm having trouble finding it. (wearing flame-retardant clothes...) I want to use boost::operators::field_operators to generate all the mathematical operators to allow Vector/scalar arithmetic. Everything works fine except for dividing scalars by vectors. Class Vector looks like this: class Vector : public std::vector<double>, boost::field_operators<Vector, boost::field_operators<Vector, double> > { // required operator+=, -=, *=, /= defined here. }; Now if I write: double x(3.0); Vector v(5), w; v[0] = 1; v[1] = 2; v[2] = 3; v[3] = 4; v[4]=5; w = 3+v; // works fine w = v+3; // works fine ... // subtract and multiply work on both sides w = v/x; // works fine w = x/v; // fails... I think the failure happens because of the way operator/ defined for mixed types something like this: T operator/(U u,T t) { T ans(u); ans/=t; return ans; } which is not what I need. Is there a way I can change the way operator/(double,Vector) works in this one case, but keep the really convenient definitions generated by field_operators otherwise? The information contained in this e-mail is confidential and/or proprietary to Capital One and/or its affiliates. The information transmitted herewith is intended only for use by the individual or entity to which it is addressed. If the reader of this message is not the intended recipient, you are hereby notified that any review, retransmission, dissemination, distribution, copying or other use of, or taking of any action in reliance upon this information is strictly prohibited. If you have received this communication in error, please contact the sender and delete the material from your computer.

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Fwd: [OT] [metaprogramming] Importance of order of delarations/definitions.
by Seweryn Habdank-Wojewódzki 22 Jun '07

22 Jun '07

Hi! Could anyone tell me if there is any example where in e.g. metaprogramming there is a need of strict order of declarations and definitions of templates? Theoretically there should not be a problem, but maybe there are some tricks where order influence on fitting types and/or for lookup of specializations. Generally the question is related to the fact, that GCC force user to put typedefs and declaration/definitions in proper order before any usage of types. And I am looking for the example which points why we can NOT mix all - when the order is important. Regards. -- |\/\/| Seweryn Habdank-Wojewódzki \/\/

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