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[statechart] : choice_point example no worky
by Noah Roberts 19 Jul '10

19 Jul '10

I've scoured the web for a reason why and have found no links at all, which is surprising since I suspect the documentation is actually in error. The documentation for statechart has this: http://www.boost.org/doc/libs/1_42_ 0/libs/statechart/doc/rationale.html#Limitations (see dynamic choice points) I'm using boost 1.42 so this should be the right document. So I tried it...and it failed with a compiler error that I looked into and makes perfect sense. The state<> template expects the third parameter to be a context, which custom_reaction is apparently not. So I made my own short version which is basically just a copy paste of the example code: #include <boost/statechart/state_machine.hpp> #include <boost/statechart/simple_state.hpp> #include <boost/statechart/state.hpp> #include <boost/statechart/custom_reaction.hpp> #include <boost/statechart/event.hpp> #include <boost/statechart/transition.hpp> #include <boost/mpl/list.hpp> #include <iostream> namespace sc = boost::statechart; struct make_choice : sc::event< make_choice > {}; // universal choice point base class template template< class MostDerived, class Context > struct choice_point : sc::state< MostDerived, Context, sc::custom_reaction< make_choice > > { typedef sc::state< MostDerived, Context, sc::custom_reaction< make_choice > > base_type; typedef typename base_type::my_context my_context; typedef choice_point my_base; choice_point( my_context ctx ) : base_type( ctx ) { this->post_event( boost::intrusive_ptr< make_choice >( new make_choice() ) ); } }; // ... struct MyChoicePoint; struct Machine : sc::state_machine< Machine, MyChoicePoint > {}; struct Dest1 : sc::simple_state< Dest1, Machine > {}; struct Dest2 : sc::simple_state< Dest2, Machine > { Dest2() { std::cout << "Dest2\n"; } }; struct Dest3 : sc::simple_state< Dest3, Machine > {}; struct MyChoicePoint : choice_point< MyChoicePoint, Machine > { MyChoicePoint( my_context ctx ) : my_base( ctx ) {} sc::result react( const make_choice & ) { if ( 0 ) { return transit< Dest1 >(); } else if ( 1 ) { return transit< Dest2 >(); } else { return transit< Dest3 >(); } } }; int main() { Machine machine; machine.initiate(); std::cin.get(); } Resulting error is the same: 1>------ Build started: Project: 2010scratch, Configuration: Debug Win32 ------ 1> scratch.cpp 1>e:\dev_workspace\production.2010rc\3rd_party\boost-1\boost-1.42-msvc10 \include\boost\statechart\simple_state.hpp(893): error C3083: 'context_type': the symbol to the left of a '::' must be a type 1> e:\dev_workspace\production.2010rc\3rd_party\boost-1\boost- 1.42-msvc10\include\boost\statechart\simple_state.hpp(632) : see reference to function template instantiation 'void boost::statechart::simple_state <MostDerived,Context,InnerInitial,historyMode>::deep_construct_inner_imp l_non_empty::deep_construct_inner_impl<InnerList>(const boost::intrusive_ptr<T> &,boost::statechart::state_machine <Machine,InitialState> &)' being compiled 1> with 1> [ 1> MostDerived=MyChoicePoint, 1> Context=Machine, 1> InnerInitial=boost::statechart::custom_reaction <make_choice>, 1> historyMode=has_no_history, 1> InnerList=boost::mpl::list <boost::statechart::custom_reaction<make_choice>>, 1> T=MyChoicePoint, 1> InitialState=MyChoicePoint 1> ] 1> e:\dev_workspace\production.2010rc\3rd_party\boost-1\boost- 1.42-msvc10\include\boost\statechart\state.hpp(81) : see reference to function template instantiation 'void boost::statechart::simple_state <MostDerived,Context,InnerInitial,historyMode>::deep_construct_inner <boost::mpl::list<T0>>(const boost::intrusive_ptr<T> &,boost::statechart::state_machine<Machine,InitialState> &)' being compiled 1> with 1> [ 1> MostDerived=MyChoicePoint, 1> Context=Machine, 1> InnerInitial=boost::statechart::custom_reaction <make_choice>, 1> historyMode=has_no_history, 1> T0=boost::statechart::custom_reaction<make_choice>, 1> T=MyChoicePoint, 1> InitialState=MyChoicePoint 1> ] 1> e:\dev_workspace\production.2010rc\3rd_party\boost-1\boost- 1.42-msvc10\include\boost\statechart\state.hpp(77) : while compiling class template member function 'void boost::statechart::state <MostDerived,Context,InnerInitial>::deep_construct (boost::statechart::state_machine<Machine,InitialState> *const &,boost::statechart::state_machine<Machine,InitialState> &)' 1> with 1> [ 1> MostDerived=MyChoicePoint, 1> Context=Machine, 1> InnerInitial=boost::statechart::custom_reaction <make_choice>, 1> InitialState=MyChoicePoint 1> ] 1> e:\dev_workspace\experimental\2010scratch\2010scratch \scratch.cpp(19) : see reference to class template instantiation 'boost::statechart::state<MostDerived,Context,InnerInitial>' being compiled 1> with 1> [ 1> MostDerived=MyChoicePoint, 1> Context=Machine, 1> InnerInitial=boost::statechart::custom_reaction <make_choice> 1> ] 1> e:\dev_workspace\experimental\2010scratch\2010scratch \scratch.cpp(45) : see reference to class template instantiation 'choice_point<MostDerived,Context>' being compiled 1> with 1> [ 1> MostDerived=MyChoicePoint, 1> Context=Machine 1> ] 1>e:\dev_workspace\production.2010rc\3rd_party\boost-1\boost-1.42-msvc10 \include\boost\statechart\simple_state.hpp(893): error C2039: 'inner_initial_list' : is not a member of 'boost::statechart::custom_reaction<Event>' 1> with 1> [ 1> Event=make_choice 1> ] 1>e:\dev_workspace\production.2010rc\3rd_party\boost-1\boost-1.42-msvc10 \include\boost\statechart\simple_state.hpp(893): error C2039: 'orthogonal_position' : is not a member of 'boost::statechart::custom_reaction<Event>' 1> with 1> [ 1> Event=make_choice 1> ] 1>e:\dev_workspace\production.2010rc\3rd_party\boost-1\boost-1.42-msvc10 \include\boost\statechart\simple_state.hpp(899): error C2039: 'deep_construct' : is not a member of 'boost::statechart::custom_reaction<Event>' 1> with 1> [ 1> Event=make_choice 1> ] 1>e:\dev_workspace\production.2010rc\3rd_party\boost-1\boost-1.42-msvc10 \include\boost\statechart\simple_state.hpp(899): error C2664: 'boost::statechart::simple_state <MostDerived,Context,InnerInitial,historyMode>::deep_construct' : cannot convert parameter 1 from 'const boost::intrusive_ptr<T>' to 'boost::statechart::state_machine<MostDerived,InitialState> *const &' 1> with 1> [ 1> MostDerived=MyChoicePoint, 1> Context=Machine, 1> InnerInitial=boost::statechart::custom_reaction <make_choice>, 1> historyMode=has_no_history 1> ] 1> and 1> [ 1> T=MyChoicePoint 1> ] 1> and 1> [ 1> MostDerived=Machine, 1> InitialState=MyChoicePoint 1> ] 1> Reason: cannot convert from 'const boost::intrusive_ptr<T>' to 'boost::statechart::state_machine<MostDerived,InitialState> *const ' 1> with 1> [ 1> T=MyChoicePoint 1> ] 1> and 1> [ 1> MostDerived=Machine, 1> InitialState=MyChoicePoint 1> ] 1> No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called So, how do I really do this? -- http://crazyeddiecpp.blogspot.com/

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[Asio] io_service destructor never completes
by Ragnar Cederlund 19 Jul '10

19 Jul '10

Hi, I'm having trouble with the io_service destructor never completing. The application I am working on uses one worker thread to handle all actual work to be done including communication on a socket in handler functions posted to the asio queue and another thread to handle the gui of the application. At a certain point in time the program decides that it has nothing more to do and calls the io_service::stop function. Shortly thereafter the thread returns from its call to the io_service::run function. The next thing that happens is that the io_service object goes out of scope and thus the io_service destructor is called. After this the thread signals that it is finished and the application exits. The problem I am seeing is that the destructor never finishes. Or actually, a customer sees this problem, but I have not been able to reproduce this so all the information I have comes from adding (excessive) logging in the boost source. The io_service destructor loops through all services and calls shutdown_service on each one. The win_iocp_io_service handles this call by entering a while loop that should complete when the outstanding_work_ variable becomes zero. Inside the loop, there is a call to GetQueuedCompletionStatus to dequeue a completion packet, which is then tested to see if it contains a valid operation that is then destroyed and the outstanding_work_ variable is decremented. In all the runs I have made, outstanding_work_ is initially 1 when the shutdown_service function is entered. The first and second calls to GetQueuedCompletionStatus come back immediately and the second results in the outstanding_work_ variable being decremented and the loop exits. Everything is fine. At the customer location however, the second call times out instead of completing immediately and it continues to do so for subsequent loop iterations until the application is forcibly closed. There is only one of our customers who gets this problem. The customer runs Windows XP SP3, but I have failed to reproduce this on my own XP test machine. We have tried both Boost version 1.43 and version 1.40 with the same result. In both cases, the customer has the problem but I cannot reproduce it. The asio behavior has changed somewhat between the versions and the description of the problem above is with version 1.43. Does anyone have any idea of what may be going on? Any hints or tips are appreciated! Could we be using asio wrong in some way that could cause this, but we're just lucky most of the time? The customer may be running in a virtual machine, could this affect io completion ports in a way that could be problematic for asio? Cheers, Ragnar

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[Testing] Help with process child
by Romulo 19 Jul '10

19 Jul '10

Hi there, good morning to everyone. I'm using the Boost Test framework to run a set of tests for an application in development and some days ago i faced some problems. In one of my tests, i run what we call "The Processes Test" which in resume is a process launcher. Within the launcher, i run, kill, detach and terminate process and now i am getting lots of ugly and erroneous messages about stack/heap/dead references and unrecognized signals. I wanted to investigate further those errors and on my logs i saw lines like: unknown location(0): fatal error in "testCaseSystemProcess2": child was killed; pid: 20182; uid: 1000; exit value: 9 But indeed i was trying to kill/terminate the children process. Is this ok? If i was really expecting the child process to die, shouldn't boost be quiet about it? Or does it mean the parent process also got killed? Also, on another test case i'm getting: unknown location(0): fatal error in "testCaseSystemProcess1": unrecognized signal Why the signal "id" is not present on the error message? How am i supposed to know which signal was emitted? Thanks for your time and patience, Rômulo.

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[Spirit] Equivalent of limit_d in spirit 2.x
by Roland Bock 19 Jul '10

19 Jul '10

Hi, Spirit 1.8 has a directive called limit_d which allowed to set the value range. Is there an equivalent for this in Spirit 2.x? Thanks and regards, Roland

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Installation problems on Snow Leopard and EPD 6.2 32 bits
by Andrés Leonardo González Mancera 19 Jul '10

19 Jul '10

Hello all, I've been trying to install boost on a Mac Pro 8-core running the latest version of Snow Leopard, Xcode and Enthough Python Distribution (EPC 6.2 32 bits). I'm mainly interested in running pyCuda. I have followed the instructions available on: http://wiki.tiker.net/PyCuda/Installation/Mac/EnthoughtPython. Nevertheless, the address-model=32_64 gives an error for the python library and libboostpython doesn't get installed. What is strange is that the instructions seemed to have worked in a setup similar to mine. Has anyone been able to install Boost on a Mac using EPD 32 bits? Am I missing something obvious? Any help will be greatly appreciated. Andrés González Mancera, Ph.D. Profesor Asistente Departamento de Ingeniería Mecánica Universidad de los Andes Cra. 1 Este No. 19A-40 ML 625 Bogotá - Colombia + (571) 3394949 ext. 2915 angonzal(a)uniandes.edu.co

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type-safe printf
by Nathan Ridge 19 Jul '10

19 Jul '10

Hello, Does boost have a type-safe implementation of printf() using C++0x variadic templates? If not, where could I find one? Thanks, Nate. _________________________________________________________________ MSN Dating: Find someone special. Start now. http://go.microsoft.com/?linkid=9734384

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[variant] custom allocator support
by Alex Dubov 19 Jul '10

19 Jul '10

Greetings. I wonder, are there any plans (or general possibility) to extend variant<> to accept custom allocator, just like containers and lots of other stuff?

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[optional] boost improvement over std::map, the default initialization requirement
by alfC 18 Jul '10

18 Jul '10

Hi, The STL has an implementation of std::map<T1, T2>. It has some designs drawbacks in my opinion. For example, the fact that T2 has to have a default copy constructor. Even if for T2, by design, doesn't make sense to have a copy constructor. The problem boils down to the fact that, in the STL design, if an key element of the map is referenced with the operator[] and it doesn't exist then an 'empty' (default) object T2 is created. In my opinion this feature is independent of the other features of a map. For example if the element doesn't exists and the context is not assignment then it could give an exception. One option would be to use std::map<T1, boost::optional<T2> >. But I am not sure if that creates other problems. It at least creates the problem of having to access elements with the ugly syntax (*m[key]) The question is, does boost have another more complete solution for this problem? (something that I would call optional_map<T1, T2>, uninitializing_map<T1, T2>, elegant_map<T1,T2>) Thank you, Alfredo BTW, This is a simple implementation that I imagine, although in my opinion a clever implementation does not even need to use the indirection of boost::optional, because the context of assigment m[key]=val can be detected with template expressions, and only the copy constructor is needed in this case. (code not tested) template<class T1, class T2> class optional_map : protected std::map<T1, boost::optional<T2> >{ typedef std::map<T1, boost::optional<T2> > base; public: using std::map<T1, boost::optional<T2> >::size; using std::map<T1, boost::optional<T2> >::empty; T2& operator[](T1 const& key){return *base::operator[](key);} T2 const& operator[](T1 const& key) const{return *base::operator[] (key);} };

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boost parameter with template
by Kraus Philipp 18 Jul '10

18 Jul '10

Hello, I would like to write a class with static methods for calculating different distributions. The algorithmens of the distribution are complet, so now I would like to put them together. Finally I would like to have only one method for using the distribution call, like: template<typename T> static T getDistribution( const distribution&, <arguments> ) I have set distribution to an enum to check the kind of distribution (normal, uniform, bernoulli, ...), so I need for <arguments> a flexible number of arguments of float / double. I've test the cstdargs, but it isn't the right structure, so I have seen the "boost parameter", but I don't understand how to create a function within my class and create a template variable in it. My getDistribution function should have one fix parameter, the first, with a name of the distrivution, and 1 or 2 parameters which are optional with default values for the distribution. Is there a complete example how to use the boost parameter (a full source code)? Thanks Phil

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Odd limitation in Fusion design ?
by John Dlugosz 18 Jul '10

18 Jul '10

I see that the "Cons" sequence is Forward-only. reverse_view requires a Bidirectional sequence, at least. The for_each iteration function goes forward. However, hand-written recursive loop on a cons-like thing can do stuff before and other stuff after the recursive call to the cdr portion. Putting stuff "after" will give a reversed processing. So, in general, a reversed_for_each is not out of the question, and can be specialized for Cons when the general form of iterating backwards does not work. I also ponder that a more general form that indeed does stuff before AND other stuff after recursing the tail would be a useful addition. It might actually perform one operation iterating forward, then perform the other operation iterating backward back to the beginning; or use recursion; depending on the nature of the container. --John TradeStation Group, Inc. is a publicly-traded holding company (NASDAQ GS: TRAD) of three operating subsidiaries, TradeStation Securities, Inc. (Member NYSE, FINRA, SIPC and NFA), TradeStation Technologies, Inc., a trading software and subscription company, and TradeStation Europe Limited, a United Kingdom, FSA-authorized introducing brokerage firm. None of these companies provides trading or investment advice, recommendations or endorsements of any kind. The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from any computer.

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