January 2006 - Boost-users - lists.preview.boost.org

statechart: interaction with environment
by Oliver.Kowalke＠infineon.com 21 Jan '06

21 Jan '06

Hello, I try to understand how boost::statechart work - so I have some questions. If the FSM implements a communication protocol how does the FSM interact with the environment? 1. Problem: How to passing callback-functions to the FSM? * The callback should be invoked if the FSM is in a certain state and some conditions are met. * Do I have to pass the callback(s) with an event which has to be injected to the FSM from outside and store them in a given state? 2. Problem: How to pass initialization parameter into the FSM? * Some states need to be initialized with parameters (for instance host and port in order to create a socket). * Do I Have to pass the parameters via injected events? 3. Problem: How to pass data between several states in an FSM? * Same as Problem 2? With best regards, Oliver

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statechart: howto connection two different FSMs
by Oliver.Kowalke＠infineon.com 21 Jan '06

21 Jan '06

Hello, The tutorial of boost::statechart contains an incomplete example of connecting two FSMs of the same type. For me it is not clear how the events are propagated between this two FSMs (concret C++-code) and if its possible to connect two FSMs of different type! Could you give me a simple (complete) example, please? Regards, Oliver

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statechart: unable to compile examples - additional compiler flags needed?
by Oliver.Kowalke＠infineon.com 21 Jan '06

21 Jan '06

Hello, I'm using statechart on LINUX with gcc-3.4.2. bjam was able to compile the examples but if I copy the StopWatch-example into a Kdevelop-project I get errors?! I assume I've to put some additional compiler-flags which are not mentioned in the tutorial. Could you help please! In file included from /opt/boost/include/boost-1_33_1/boost/statechart/simple_state.hpp:13, from /opt/boost/include/boost-1_33_1/boost/intrusive_ptr.hpp:35, from /opt/boost/include/boost-1_33_1/boost/statechart/detail/state_base.hpp:1 6, from /opt/boost/include/boost-1_33_1/boost/statechart/state_machine.hpp:16, from /opt/boost/include/boost-1_33_1/boost/intrusive_ptr.hpp:34, from /opt/boost/include/boost-1_33_1/boost/statechart/event_base.hpp:15, from /opt/boost/include/boost-1_33_1/boost/statechart/event.hpp:11, from /home/kowalke/Projects/tcpproto/src/tcpproto.cpp:33: /opt/boost/include/boost-1_33_1/boost/statechart/detail/leaf_state.hpp:2 6: Fehler: Fehler beim Parsen before `<' token /opt/boost/include/boost-1_33_1/boost/statechart/detail/leaf_state.hpp:3 6: Fehler: destructors must be member functions /opt/boost/include/boost-1_33_1/boost/statechart/detail/leaf_state.hpp: In function `void boost::statechart::detail::leaf_state()': /opt/boost/include/boost-1_33_1/boost/statechart/detail/leaf_state.hpp:3 6: Fehler: ` void boost::statechart::detail::leaf_state()' redeclared as different kind of symbol /opt/boost/include/boost-1_33_1/boost/statechart/detail/leaf_state.hpp:2 6: Fehler: previous declaration of `template<class Allocator, class RttiPolicy> class boost::statechart::detail::leaf_state' /opt/boost/include/boost-1_33_1/boost/statechart/detail/leaf_state.hpp:2 6: Fehler: previous non-function declaration `template<class Allocator, class RttiPolicy> class boost::statechart::detail::leaf_state' ... with best regards, Oliver

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gcc3.2 preprocessor concatenation or not on negative numbers
by Andy Little 21 Jan '06

21 Jan '06

Hi all, Using gcc3.2 the concatenation of 1##Num where Num is negative leaves a space eg 1e#-1 --> 1e -1 as can be seen by the preprocessed output below. The only way round it that I can see is to simply not use a macro for this compiler Is there a preprocessor workaround for this problem? Is this even the correct behaviour? Any help appreciated. #define POW_EVAL(Num, Float_type)\ template <>\ struct pow_eval< \ Float_type BOOST_PP_COMMA() Num BOOST_PP_COMMA()\ 1 BOOST_PP_COMMA() false\ >{\ enum{ required = true};\ typedef Float_type result_type;\ result_type operator()()const\ { result_type result\ = static_cast< Float_type > (1e ## Num);\ return result;\ }\ }; POW_EVAL(-60, double) POW_EVAL(-59, double) POW_EVAL(58, double) POW_EVAL(57, double) // preprocessor output template <> struct pow_eval< double , -60 , 1 , false >{ enum{ required = true}; typedef double result_type; result_type operator()()const { result_type result = static_cast< double > (1e- 60); return result; } }; template <> struct pow_eval< double , -59 , 1 , false >{ enum{ required = true}; typedef double result_type; result_type operator()()const { result_type result = static_cast< double > (1e- 59); return result; } }; template <> struct pow_eval< double , 58 , 1 , false >{ enum{ required = true}; typedef double result_type; result_type operator()()const { result_type result = static_cast< double > (1e58); return result; } }; template <> struct pow_eval< double , 57 , 1 , false >{ enum{ required = true}; typedef double result_type; result_type operator()()const { result_type result = static_cast< double > (1e57); return result; } }; regards Andy Little

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regex format string extension for more than nine captures
by Evan Burkitt 21 Jan '06

21 Jan '06

I need to be able to reformat match_results that contain more than nine captures using format strings. I'm looking for advice as to the easiest way to accomplish this. Is there some existing work I can build on or borrow from? I need syntax similar to the boost extended syntax, possibly using two digits for the capture number, e.g., '$01' It's important to me to be able to use the extended syntax's conditional expression '?Ntrue-expression:false-expression', again probably with two digits 'NN' in place of the single 'N'. Any help would be greatly appreciated. -eb-

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[tuple] no easy access to get function
by Frank Birbacher 21 Jan '06

21 Jan '06

Hi! Today I wanted to std::transform a range of tuples into a sequence of one element. I thought I could just take the address of some tuple::get<N> function. Maybe also specify the Tuple type as template parameter. But from the source I figured the get function is not designed in a way that would allow me easy access. I had to write myself an additional function for this task (see below). Am I trying the wrong way? Or would you fix the implementation? template<size_t N, typename Tuple> typename boost::tuples::element<1,Tuple>::type const& getTupleElement(const Tuple& tuple) { return boost::get<N>(tuple); } to do: transform(..., ..., ..., &::getTupleElement<1,Tuple>); or //using boost::lambda for_each(..., ..., var(i) += bind(&::getTupleElement<1,Tuple>, _1)); I'd rather want to take the address of boost::tuple::get<N,Tuple>, but the template parameters won't match. Frank

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Parse errors when building against Insure++ by ParaSoft.
by Sven Delmas 20 Jan '06

20 Jan '06

I am trying to do some memory allocation debugging using Insure++ on my Windows machine. They use their own parser, and inject all kinds of fun stuff. However, their parser appears to be more restrictive (or just plain different) than the usual parsers. I end up with two parser errors: One in boost/details/indirect_traits.hpp (line 254 in boost 1.33.1): BOOST_STATIC_CONSTANT( bool, value = sizeof(detail::is_function_ref_tester(t,0)) == sizeof(::boost::type_traits::yes_type)); The error is: namespace "boost::detail" has no member is_function_ref_tester I can resolve that by taking the detail:: away, which seems to make sense if it indeed not part of the namespace. Can anyone confirm whether that is a valid solution/issue? The second issue is in boost/pool/detail/ct_gcd_lcm.hpp (line 68 in boost 1.33.1): BOOST_STATIC_CONSTANT(unsigned, value = ct_gcd2<B>::helper<A % B>::value); The error is: the global scope has no value I can resolve this by switching to the other branch with respect to the macro BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION. That compiles fine for VC 7.0, VC 7.1 and VC 8.0, so my question is whether it will produce the correct result, and if so, whether the visualc.hpp should be adjusted for those compiler. Any help would be appreciated. Thanks, Sven

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Serialization "stream error" when using binary_iarchive/binary_oarchive & make_binary_object, but xml_iarchive & text_iarchive suceeds
by Terence Wilson 20 Jan '06

20 Jan '06

I've been scratching my head trying to figure this one out for a few days. My code serializes xml_iarchive & text_iarchive with no problems, however, when I substitute the binary_iarchive I get a "stream error" serialization exception thrown during the make_binary_object call when reading a binary file: template<class Archive> void serialize(Archive & ar, const unsigned int) { ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(CImageDataBase2D); if (Archive::is_loading::value) { Alloc(); } //ar & boost::serialization::make_nvp("ImageData", boost::serialization::make_binary_object(m_pData, sizeof(T)*m_x*m_y)); const int blobSize=sizeof(T)*m_x*m_y; _ASSERTE(blobSize); ar & boost::serialization::make_nvp("ImageData", boost::serialization::make_binary_object(m_pData, blobSize)); } I've tried to excise the relevant code to a console project, however, it has tentacles and will take a few more days. In the mean time I would appreciate help from anyone that might have a suggestion. I've looked at the code and can find nothing wrong, as I said, ASCII and XML serialization works flawlessly I'm using Visual Studio 8 with Boost 1.33.1.

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Getting Environment Variables
by Merrill Cornish 20 Jan '06

20 Jan '06

Is there a Boost way to get environment variables? I _thought_ I had seen a reference to that in the program options libarary, but I can't find it now. Merrill

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Re: [Boost-users] gcc3.2 preprocessor concatenation or not on negative numbers
by Merrill Cornish 20 Jan '06

20 Jan '06

Andy, Thinking about it some more, I think I was wrong. Merrill

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