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Re: [Boost-users] [iostreams] compilation error with wstring
by Chad Walters 24 Jul '07

24 Jul '07

> Date: Tue, 24 Jul 2007 15:48:52 +0200 > From: Pipoun <pipoun(a)gmail.com> > > I'm trying to use the iostream libs using wstring, but I'm struggling > with wstring. > <snip> This might be related to a bug I filed a little while ago -- a simple copy-paste bug as far as I can tell: http://svn.boost.org/trac/boost/ticket/1003 Try applying my patch and see if it fixes it. Chad Walters

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[iostreams] compilation error with wstring
by Pipoun 24 Jul '07

24 Jul '07

Hello, I'm trying to use the iostream libs using wstring, but I'm struggling with wstring. Her is my little piece of code: using namespace std; using namespace boost; struct Formatter { std::wstring operator() ( const match_results<const wchar_t*>& _Match ) { //TODO return wstring(); } }; int main(int argc, char** argv) { wstring File; //skipped steps to put data in wregex Regx(L"bla"); iostreams::wregex_filter Filter( Regx, Formatter() ); iostreams::filtering_wostream Out; Out.push( Filter ); Out.push( iostreams::wfile_sink("FilenameFormatted.txt") ); Out << File; } I'm using boost 1_34. If I compile this code vith vc80 express, I get an error: boost/iostreams/filter/aggregate.hpp(97) : error C2664: 'void boost::iostreams::aggregate_filter<Ch,Alloc>::do_write<Sink>(Sink &,const char *,std::streamsize)' : cannot convert parameter 2 from 'wchar_t *' to 'const char *' I'm a little lost :( Am I doing something wrong? Thank you very much for your help! pipoun

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[foreach] boost_foreach_is_lightweight_proxy doesn't work
by Raider 24 Jul '07

24 Jul '07

Hi, i'm trying to modify rvalue container using Boost.ForEach: #include <string> #include <vector> #include <boost/foreach.hpp> typedef std::vector<std::string> vec; inline boost::mpl::true_ * boost_foreach_is_lightweight_proxy(vec *&, boost::foreach::tag) { return 0; } vec GetVector() { vec v; v.push_back("hello"); v.push_back("world"); return v; } int main() { // compiles ok GetVector().push_back("oh god, it's writable!"); // next line gives "unable to convert `const string' to `string&'" BOOST_FOREACH(std::string& String, GetVector()) String.clear(); return 0; } It doen't compiles (MCVC 8.0) - it looks like boost_foreach_is_lightweight_proxy is ignored. What's wrong?

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Boost.signals has no shared_connection
by gast128 24 Jul '07

24 Jul '07

Dear all, I was playing with Boost.Signals and stumbles across a problem which required something like the equivalent of a shared_connenction, i.e. the last reference to it will finally disconnent. This can of course be simulated with a boost::shared_ptr<scoped_connection>, but native support for it is always preferable. The use is that some change manager returns a connection which goes through several application layers. The time the connection finally arives at destination, it has felt multiple ctor's and dtors: View::View(Doc* p) : m_con(p->Register(&OnUpdate) { } shared_connection Doc::Register(void (View::* pmf)(), View* p) { return m_pCm->Register(pmf, p) } etc.. Or did I not read the documentation properly? Wkr, me

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[statechart]LNK2001 Error on VC 8.0
by Jiang Miao 24 Jul '07

24 Jul '07

Here is a tutorial. I compile succeeded at DEBUG mode, but failed at RELEASE mode. And I got LNK2001 Error. #include <boost/statechart/event.hpp> #include <boost/statechart/state_machine.hpp> #include <boost/statechart/simple_state.hpp> #include <boost/statechart/transition.hpp> namespace sc = boost::statechart; struct EvStartStop : sc::event< EvStartStop > {}; struct EvReset : sc::event< EvReset > {}; struct Active; struct StopWatch : sc::state_machine< StopWatch, Active > {}; struct Stopped; struct Active : sc::simple_state< Active, StopWatch, Stopped > { typedef sc::transition< EvReset, Active > reactions; }; struct Running : sc::simple_state< Running, Active > { typedef sc::transition< EvStartStop, Stopped > reactions; }; struct Stopped : sc::simple_state< Stopped, Active > { typedef sc::transition< EvStartStop, Running > reactions; }; // A state can define an arbitrary number of reactions. That's // why we have to put them into an mpl::list<> as soon as there // is more than one of them // (see Specifying multiple reactions for a state). int main() { StopWatch myWatch; myWatch.initiate(); myWatch.process_event( EvStartStop() ); myWatch.process_event ( EvStartStop() ); myWatch.process_event( EvStartStop() ); myWatch.process_event( EvReset() ); return 0; } //Output Linking... statechart.obj : error LNK2001: unresolved external symbol "public: void __thiscall boost::statechart::detail::no_context<struct EvReset>::no_function(struct EvReset const &)" (?no_function@?$no_context@UEvReset@@@ detail@statechart @boost@@QAEXABUEvReset@@@Z) statechart.obj : error LNK2001: unresolved external symbol "public: void __thiscall boost::statechart::detail::no_context<struct EvStartStop>::no_function(struct EvStartStop const &)" (?no_function@?$no_context@UEvStartStop@@@ detail@statechart @boost@@QAEXABUEvStartStop@@@Z) i:\programme\test\statechart\Release\statechart.exe : fatal error LNK1120: 2 unresolved externals How can I solve the problem? Thank you.

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[statechart] context<>() assert failed in destructor function in VC8.0
by Jiang Miao 24 Jul '07

24 Jul '07

I wrote a simple code. source file: #include <boost/statechart/event.hpp> #include <boost/statechart/transition.hpp> #include <boost/statechart/simple_state.hpp> #include <boost/statechart/state.hpp> #include <boost/statechart/state_machine.hpp> #include <boost/statechart/custom_reaction.hpp> #include <boost/shared_ptr.hpp> #include <boost/weak_ptr.hpp> #include <boost/mpl/list.hpp> #include <iostream> #include <string> using namespace std; namespace sc=boost::statechart; namespace mpl=boost::mpl; struct EvtEat:sc::event<EvtEat>{}; struct EvtStop:sc::event<EvtStop>{}; struct Eating; struct Idle; class Human:public sc::state_machine< Human, Idle > { public: void show(void) { cout<<__FUNCTION__<<endl; } }; struct Idle:sc::state< Idle, Human > { Idle(my_context ctx):my_base(ctx) { context<Human>().show(); //ok }; ~Idle(void) { context<Human>().show(); //assert failed }; }; struct Eating:sc::state< Eating, Human > { Eating(my_context ctx):my_base(ctx) { }; ~Eating(void) { context<Human>(); } }; int main(int argc, char* argv[]) { Human human; human.initiate(); return 0; } /* In debug mode.It output Human::show Assertion failed: dynamic_cast<Target>(x) == x, file p:\programme\libs\boost\include\boost-1_35\boost\cast.hpp, line 97 */ Why does it assert failed and how to modify the source? Thank you.

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Re: [Boost-users] [Serialization] is_serializable trait?
by Roman Perepelitsa 24 Jul '07

24 Jul '07

> Re: [Serialization] is_serializable trait? (Chris Fairles) > > I also took a stab at making a boostified version: > > #include <iostream> > #include <boost/type_traits/config.hpp> > #include <boost/utility/enable_if.hpp> > #include <boost/type_traits/is_fundamental.hpp> > #include <boost/type_traits/detail/yes_no_type.hpp> > #include <boost/type_traits/detail/bool_trait_def.hpp> > > namespace boost { > namespace detail { > > template <class T> > struct has_serialize_mem_fun { > typedef void (T::*SerializationFun)(int &, unsigned); > > template <SerializationFun> > struct A {}; > > template <class Q> > static ::boost::type_traits::yes_type > has_serialize_mem_fun_tester(A<&Q::serialize>*); > > template <class Q> > static ::boost::type_traits::no_type has_serialize_mem_fun_tester(...); > > BOOST_STATIC_CONSTANT(bool, value = > (sizeof(has_serialize_mem_fun_tester<T>(0)) == > sizeof(::boost::type_traits::yes_type))); > > }; > template <typename T, typename IsFundamental = void> > struct is_serializable_impl > { > BOOST_STATIC_CONSTANT(bool, value = has_serialize_mem_fun<T>::value); > }; > > template <typename T> > struct is_serializable_impl<T, typename ::boost::enable_if< > ::boost::is_fundamental<T> >::type> > { > BOOST_STATIC_CONSTANT(bool, value = true); > }; > } > > BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_serializable,T,::boost::detail::is_serializable_impl<T>::value) > > } > > struct A { > template <class Stream> > void serialize(Stream & strm, unsigned version) {} > }; > > struct B {}; > > struct C { void serialize() {} }; > > int main() > { > using namespace std; > cout > << boolalpha > << boost::is_serializable<A>::value << '\n' // true > << boost::is_serializable<int>::value << '\n' // true > << boost::is_serializable<float>::value << '\n' // true > << boost::is_serializable<double>::value << '\n' // true > << boost::is_serializable<char>::value << '\n' // true > << boost::is_serializable<B>::value << '\n' // false > << boost::is_serializable<C>::value << '\n' // false > << boost::is_serializable<string>::value << endl; //false but > should be true > } > > Needs specializations for standard containers as well but this suits > my needs currently. Thoughts? I tried to implement is_non_intrusively_serializable metafunction, but found no general solution. Although I've impelented it for all types which are instances of some class template. For example, it works correctly for vector<int>, some_class<double, string>, etc. Note that it is possible to create metafunction which determines whether type is instance of class template or not. So, we have the following: - is_intrusivelly_serializable metafunction. - is_class_template_instance metafunction. - is_non_intrusively_serializable metafunction, which currently works only for class template instances. Probably someone can implement the last missing case? That is we need is_non_intrusively_serializable implementation for types, which are not class template instances (int, some_nontemplate_class, etc). Here is is_non_intrusively_serializable restricted to class templates. #include <boost/serialization/serialization.hpp> #include <boost/type_traits/remove_cv.hpp> #include <boost/type_traits/detail/yes_no_type.hpp> #include <boost/preprocessor.hpp> #include <boost/static_assert.hpp> #include <boost/serialization/vector.hpp> namespace detail { struct tag {}; using boost::serialization::serialize; #define BOOST_PP_LOCAL_LIMITS (1, 10) #define BOOST_PP_LOCAL_MACRO(N) \ template < \ class Archive, \ template <BOOST_PP_ENUM_PARAMS(N, class I)> class T, \ BOOST_PP_ENUM_PARAMS(N, class T) \ > \ tag serialize( \ Archive & ar, \ T<BOOST_PP_ENUM_PARAMS(N, T)> &, \ const unsigned \ ); #include BOOST_PP_LOCAL_ITERATE() tag operator,(tag, int); boost::type_traits::no_type check(tag); template <class T> boost::type_traits::yes_type check(T const&); template <class T> struct impl { static typename boost::remove_cv<T>::type & x; static const int & archive; static const unsigned version; static const bool value = sizeof(check((serialize(archive, x, version), 0))) == sizeof(boost::type_traits::yes_type); }; } template <class T> struct is_non_intrusively_serializable : detail::impl<T> {}; template <class T> struct A {}; int main() { BOOST_STATIC_ASSERT( is_non_intrusively_serializable<std::vector<int> >::value); BOOST_STATIC_ASSERT( !is_non_intrusively_serializable<A<int> >::value); } Regards, Roman Perepelitsa Deutsche Bank Moscow +7 (495) 660-74-08 --- This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and delete this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden. Please refer to http://www.db.com/en/content/eu_disclosures.htm for additional EU corporate and regulatory disclosures.

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Detecting Valid Expressions for a Type at Compile-Time
by Martin Ecker 24 Jul '07

24 Jul '07

Hi, Is there a way, using SFINAE tricks and potentially the techniques used in the Boost Concept Check Library, to detect at compile-time if a type T supports a certain expression? In my case, I'm interested if T supports operator ==. So I'm basically looking for a compile-time predicate so that this compiles: struct my_struct { int i; }; struct my_struct2 { int i; }; bool operator == (my_struct2 const&, my_struct2 const&) const; BOOST_STATIC_ASSERT((supports_comparison_operator<int>::value)); BOOST_STATIC_ASSERT((!supports_comparison_operator<my_struct>::value)); BOOST_STATIC_ASSERT((supports_comparison_operator<my_struct2>::value)); Thanks, Martin

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Serialization
by Alejandro Rubinos Carbajal 23 Jul '07

23 Jul '07

How can i serialize an object of the class tm that belongs to time.h, and also i will like to serialize a char * object. Thanks

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[intrusive][interprocess] Online documentation site changed
by Ion Gaztañaga 23 Jul '07

23 Jul '07

Hi to all, Due to recent problems with the automatically generated Boost documentation in Boost CVS and some other problems with my old website, I've just uploaded up-to-date (CVS HEAD documentation) Boost.Intrusive and Boost.Interprocess documentation to these sites: http://igaztanaga.drivehq.com/intrusive http://igaztanaga.drivehq.com/interprocess These sites have no ads, so I expect better user experience. I've requested the cancellation of the old site (www.prohosting.com) so I hope this helps Intrusive and Interprocess user experience until Boost 1.35 is released. Regards, Ion

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