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Re: [Boost-users] [MSM] problem compiling a functor-guard using a flaginside.
by Christophe Henry 11 Apr '11

11 Apr '11

>while developing I want to use functors for a guard. The state machine compiles well until I added a >function call to the FSM which has a template parameter. Then I always got the following error message >while compiling it with gcc 4.4.1. >SubtractionControllerNew.cpp: In member function ‘bool<unnamed>::player_::isCDLoaded::operator()(const EVT&, FSM&, SourceState&, TargetState&)’: >SubtractionControllerNew.cpp:175: error: expected primary-expression before ‘>’ token >SubtractionControllerNew.cpp:175: error: expected primary-expression before ‘)’ token >Does anybody know why this happens and how to circumvent it? I admit C++ is sometimes full of hard-to-get rules :( Try adding a template keyword: struct isCDLoaded { template <class EVT,class FSM,class SourceState,class TargetState> bool operator()(EVT const& ,FSM& fsm,SourceState& ,TargetState& ) { //return fsm.is_contained(); // this works well return fsm.template is_flag_active<CDLoaded>(); // Line 175 } }; HTH, Christophe

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[Fusion] Output of adapted ADT
by Tore Halvorsen 11 Apr '11

11 Apr '11

Hi, I'm trying to output a string from an adapted class, but I'm getting 1>main.cpp(33): error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'boost::fusion::extension::adt_attribute_proxy<foo,0,false>' (or there is no acceptable conversion) for the following code (boost 1_46_1, msvc2010) Is there a header I'm missing? Very similar code works for BOOST_FUSION_DEFINE_STRUCT - and using ints or doubles also work... #include <iostream> #include <string> #include <ostream> #include <boost/fusion/include/adapted.hpp> #include <boost/fusion/sequence.hpp> class foo { public: foo(std::string const& str) : s(str) { } std::string const& get_s() const { return s; } void set_s(std::string const& str) { s = str; } private: std::string s; }; BOOST_FUSION_ADAPT_ADT( foo, (std::string const&, std::string const&, obj.get_s(), obj.set_s(val)) ); int main(int argc, char* argv[]) { foo f("foo"); std::cout << boost::fusion::front(f) << std::endl; return EXIT_SUCCESS; } -- Eld på åren og sol på eng gjer mannen fegen og fjåg. [Jøtul] <demo> 2011 Tore Halvorsen || +052 0553034554

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[Boost.Thread] Multithreaded Multithreaded Server
by Ian Mallett 10 Apr '11

10 Apr '11

Hi, Fairly new to Boost. Bear with me. I'm trying to write a multithreaded multithreaded server (two multithreaded operations): ideally, there should be a single process, containing at least two threads. The first thread handles various tasks (and can start other threads to help it as well). The other thread waits for incoming connections, and adds a new thread for each one: Server process: -Thread 1 (Handle background server operations, etc.) -helper thread 1 -helper thread 2 ... -helper thread *n* -Thread 2 (Listen for incoming connections. When found, make a new connection thread to handle it) -connection thread 1 -connection thread 2 ... -connection thread *n* I began by making heavy use of the example here<http://www.boost.org/doc/libs/1_36_0/doc/html/boost_asio/example/echo/async…>. Please see my attached files for my implementation. The classes "mMindThreadServerListener" and "mMindServerHandlerClient" correspond to "server" and "session", respectively. "mMindServer" is the highest level (server process). In it, there's a thread group that contains "Thread 1" ("_thread_connection_pruner", which kills unused connections, and represents a background server operation) and "Thread 2" ("_thread_listener", which listens for incoming connections). Thread 2's need to make other threads seems to be handled by boost::asio::io_service. Unfortunately, when a connection is found, Thread 1 stops. I can only attribute this to a lock boost::asio::io_service puts, although I have no idea. Can someone explain what's going on, and possibly a better way to do this? Thanks, Ian

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BOOST and Android
by Claude 10 Apr '11

10 Apr '11

Hi! It is possible compile/use BOOST with Android (3.0?) NDK? -- View this message in context: http://boost.2283326.n4.nabble.com/BOOST-and-Android-tp3439871p3439871.html Sent from the Boost - Users mailing list archive at Nabble.com.

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Re: [Boost-users] [MSM] Use events twice
by Christophe Henry 10 Apr '11

10 Apr '11

> I'm using MSM to implement a client for a simple network application. Basically, the server sends messages and the client changes state and responds to them as appropriate. > > One of these messages is THROW. THROW gets two arguments: an identifier (0-3) and a value. My client is supposed to sum up the values for consecutive THROW events with the same identifier, and on a change of identifier, store the sum somewhere and start over for the new identifier. > > So I have three states (id0, id1, id2 - there's some special handling, which is why they're separate states) and an event Throw(id, value). The transitions for idN are: > Throw(my id, value) -> no switch, state.sum += value > Throw(other id, value) -> switch to state of other id, reprocess event, storing the sum is handled by the exit action > > In other words, I want the next state to immediately handle the event as well, because there's a value there I need to store. The question is, how do I do this? > > Here's a sequence of events and actions that could occur: > E1: [init] Throw(0, 4) -> [id0: ?] > Entry [id0: ?] -> [id0: 0] > [id0: 0] reprocess E1 -> [id0: 4] > E2: [id0: 4] Throw(0, 8) -> [id0: 12] > E3: [id0: 12] Throw(1, 7) -> [id1: ?] > Exit [id0: 12] -> save 12 > Entry [id1: ?] -> [id1: 0] > [id1: 0] reprocess E3 -> [id1: 7] Hi Sebastian, Let's see if I get it. Reprocessing is not going to be the problem, I suppose. An action reprocessing an event untouched would be: struct reprocess { template <class Fsm,class Evt,class SourceState,class TargetState> void operator()(Evt const& evt,Fsm& fsm,SourceState& ,TargetState& ) { fsm.process_event(evt); } }; MSM has a message queue by default so you have no risk of deadlocking yourself. Actually you might not even need to reprocess if you use internal actions and transition conflicts, so I suggest a different version. For every Throw event, sou create a conflict between a state internal transition (not necessary but more elegant and with more reuse, see below) and an external one, leading to another state if the id contained in Throw is not the one from the current state. If it is the one from the current state, we add the value from the event. I also added an Init state to make it simpler. Now, all I need to do is make the states template classes and write just one. I attach an example. Please tell me if that's what you're looking for. Christophe

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any_range vs. “canonical form” - what is the latter?
by John Funnell 10 Apr '11

10 Apr '11

Boost's any_range documentation says the following: "Despite the underlying any_iterator being the fastest available implementation, the performance overhead of any_range is still appreciable due to the cost of virtual function calls required to implement increment, decrement, advance, equal etc. Frequently a better design choice is to convert to a canonical form." What does the author mean by a "canonical form"? Can someone give an example? Many thanks [question originally asked at http://stackoverflow.com/questions/5601303]

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boost::mpl::plus changes type
by Peter Foelsche 10 Apr '11

10 Apr '11

It is a major annoyance that these arrithmetic operations return a different type than the input! I mean I input boost::mpl::long_ and I get a boost::mpl::integral_c Peter

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boost::mpl::abs missing
by Peter Foelsche 10 Apr '11

10 Apr '11

There is no boost::mpl::abs Peter

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[network] cpp-netlib v0.9-beta out now!
by Dean Michael Berris 09 Apr '11

09 Apr '11

Hi Everyone, Apologies for the cross-post, but I just want to announce that after a couple months delay because of some outstanding bugs and TODO items that needed to get dealt with, I am now ready to package a 0.9 release and with that in mind I've just uploaded the 0.9-beta release of cpp-netlib. When the beta period (1 week) is over and all outstanding bugs are addressed, the 0.9 release will be the basis for submission for review to the Boost C++ Library. You can get the beta from: https://github.com/cpp-netlib/cpp-netlib/downloads What's New in 0.9 (taken from the documentation): - IMPORTANT BREAKING CHANGE: By default all compile-time heavy parser implementations are now compiled to external static libraries. In order to use cpp-netlib in header-only mode, users must define the preprocessor macro BOOST_NETWORK_NO_LIB before including any cpp-netlib header. This breaks code that relied on the version 0.8.x line where the library is strictly header-only. - More consistent message API for client and server messages (request and response objects). - Refactoring of internal implementations to allow better separation of concerns and more manageable coding/documentation. - Client and Server constructors that support Boost.Parameter named parameters. - Client and Server cosntructors now take in an optional reference to a Boost.Asio io_service to use internally. - Documentation updates to reflect new APIs. This Beta has been tested mainly on Linux (GCC 4.4, 4.5) and Mac OS X (10.6.7, Xcode 3.2.x w/ GCC 4.2.1) builds against Boost trunk and Boost 1.45. Note that cpp-netlib does NOT work with Boost 1.46.1 because of some breaking changes in the Boost.Spirit customization points have caused cpp-netlib to cease to play well with it. That said, the issues have been addressed in Boost trunk and should be fixed in Boost.147. Thanks to everyone who contributed to making this Beta possible, namely Emre Turkay, Oleg Malashenko, and other users that filed issues on the Github issue tracker. Have a good day everyone and I do look forward to feedback! -- Dean Michael Berris http://about.me/deanberris

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[Interprocess] shared_ptr in a non-throwing mode
by Pietro Versari 09 Apr '11

09 Apr '11

Hi Ion (and everyone else), I'm a newbye and I have only one simple question: how can I construct a shared_ptr in a non-throwing mode? This example throw if there is enough space for MyType but isn't enough for my_shared_ptr: typedef managed_shared_ptr<MyType,managed_shared_memory>::type my_shared_ptr; my_shared_ptr sh_ptr = make_managed_shared_ptr( segment.construct<MyType>("object to share", std::nothrow)(), segment); Thanks, Pietro Versari

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