August 2008 - Boost-users - lists.preview.boost.org

[boost::any] Using any as an abstract class container
by joel falcou 30 Aug '08

30 Aug '08

Let's say i have a hierarchy of object that all inherits from a abse class called base_impl. Among those classes, most of them are tempalte that have large, complex type. My idea was to use boost::any to store any of this classes' instances, any_cast them back to base_impl* and call one of the base_impl virtual method. Basically I did this : struct expression_impl { virtual ~expression_impl() {} virtual void evaluate() const = 0; }; struct expression { template<class T> expression( T const& x ) : mExpr(x) {} void evaluate() { boost::any_cast<expression_impl*>(mExpr)->evaluate(); } boost::any mExpr; }; Alas this fails in a bad_any_cast exception. Considering that the basic use case of expression is : expression e = /some_function_making_emporary_base_impl_instance(); I can't rely on stroing a pointer in the boost::any member. Any solution to this problem or am I doing something wrong.

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1.34.1: boost bind issue with function template
by mbrodeur65 30 Aug '08

30 Aug '08

Hi, I'm having problem compiling this piece of code in VC++ 7.1. I don't know if it is a bug in this environment but it compiles properly under gcc 3.4.4. thanks for any help !!! #include <boost/signal.hpp> #include <boost/bind.hpp> boost::signal<void (int)> m_signal; struct Foo { void test(int x) {} }; template <typename C> boost::signals::connection Subscribe(C* ptr,void (C::*callback)(int)) { return m_signal.connect(boost::bind(callback,ptr,_1)); } int main() { Foo f; Subscribe(&f, &Foo::test); return 0; } Here are the compiler errors: c:\Program Files\boost\boost_1_34_1\boost\visit_each.hpp(25) : warning C4675: 'void boost::_bi::visit_each<Visitor,void,boost::_mfi::mf1<R,T,A1>,boost::_bi::list2<boost::_bi::list_av_2<C *,A2>::B1,A2>>(V &,const boost::_bi::bind_t<R,F,L> &,int)' : resolved overload was found by argument-dependent lookup with [ Visitor=boost::signals::detail::bound_objects_visitor, R=void, T=Foo, A1=int, C=Foo, A2=boost::arg<1>, V=boost::signals::detail::bound_objects_visitor, F=boost::_mfi::mf1<void,Foo,int>, L=boost::_bi::list2<boost::_bi::list_av_2<Foo *,boost::arg<1>>::B1,boost::_bi::list_av_2<Foo *,boost::arg<1>>::B2> ] c:\Program Files\boost\boost_1_34_1\boost\bind.hpp(1173) : see declaration of 'boost::_bi::visit_each' c:\Program Files\boost\boost_1_34_1\boost\signals\slot.hpp(123) : see reference to function template instantiation 'void boost::visit_each<boost::signals::detail::bound_objects_visitor,F>(Visitor &,const T &)' being compiled with [ F=boost::_bi::bind_t<void,boost::_mfi::mf1<void,Foo,int>,boost::_bi::list2<boost::_bi::list_av_2<Foo *,boost::arg<1>>::B1,boost::_bi::list_av_2<Foo *,boost::arg<1>>::B2>>, Visitor=boost::signals::detail::bound_objects_visitor, T=boost::_bi::bind_t<void,boost::_mfi::mf1<void,Foo,int>,boost::_bi::list2<boost::_bi::list_av_2<Foo *,boost::arg<1>>::B1,boost::_bi::list_av_2<Foo *,boost::arg<1>>::B2>> ] c:\Documents and Settings\mbrodeur\My Documents\Visual Studio Projects\testboost\testboost\testboost.cpp(16) : see reference to function template instantiation 'boost::slot<SlotFunction>::slot<boost::_bi::bind_t<R,F,L>>(const boost::_bi::bind_t<R,F,L> &)' being compiled with [ SlotFunction=boost::signal1<boost::detail::function_traits_helper<boost::add_pointer<void (int)>::type>::result_type,boost::detail::function_traits_helper<boost::add_pointer<void (int)>::type>::arg1_type,boost::last_value<void>,int,std::less<int>,boost::function<void (int)>>::slot_function_type, R=void, F=boost::_mfi::mf1<void,Foo,int>, L=boost::_bi::list2<boost::_bi::list_av_2<Foo *,boost::arg<1>>::B1,boost::_bi::list_av_2<Foo *,boost::arg<1>>::B2> ] c:\Documents and Settings\mbrodeur\My Documents\Visual Studio Projects\testboost\testboost\testboost.cpp(22) : see reference to function template instantiation 'boost::signals::connection Subscribe<Foo>(C *,void (__thiscall Foo::* )(int))' being compiled with [ C=Foo ] thanks ! -- View this message in context: http://www.nabble.com/1.34.1%3A-boost-bind-issue-with-function-template-tp1… Sent from the Boost - Users mailing list archive at Nabble.com.

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[gil] confusion about the usage of color_converted_view in the designguide
by Stefan Seiffarth 30 Aug '08

30 Aug '08

Hello, I'm a bit confused about the source code snippet at http://www.boost.org/doc/libs/1_36_0/libs/gil/doc/html/gildesignguide.html#… and especially, since I can't find any way to get that snippet compiled: step3=color_converted_view<rgb8_view_t,gray8_pixel_t>(step2); 1.) What's the proper return type of color_converted_view in this example? 2.) Is the snippet above correct at all?, the template is defined as: 00181 template <typename DstP, typename View> 00182 inline typename color_converted_view_type<View,DstP>::type 00183 color_converted_view(const View& src) { 00184 return color_converted_view<DstP>(src,default_color_converter()); 00185 } in http://www.boost.org/doc/libs/1_36_0/libs/gil/doc/html/g_i_l_0221.html So shouldn't it be color_converted_view<gray8_pixel_t,rgb8_view_t>?, with pixel type first and view type second Which leads me to the next question why is the type order swapped for the return value type definition? The following snippet: rgb8_image_t img; jpeg_read_image("bild.jpg", img); jpeg_write_view("bild_transform.jpg", color_converted_view<gray8_pixel_t,rgb8_view_t>(view(img))); atleast outputs a properly grayscaled image, the original line from the example obviously throws an error during compilation, but I still like to know what the proper return type of color_converted_view is. Thanks for any help, Stefan

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Using boost:unordered_map with std::bitset
by Sean Farrow 30 Aug '08

30 Aug '08

Hi: Can I use boost::Unordered_Map with std::bitset? Do I needto write my own operators, or are he required operators provided? Cheers Sean. __________ Information from ESET NOD32 Antivirus, version of virus signature database 3401 (20080829) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com

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Problem with boost.asio
by Moji 30 Aug '08

30 Aug '08

I use boost.asio timer in my program. and the timer require the boost.system because of the boost::system::error_code in hanlder functions. I use this command to get output from this: g++ timer3.cpp -lboost_thread but this cause this error: /tmp/ccNQAhKx.o: In function `__static_initialization_and_destruction_0(int, int)': timer3.cpp:(.text+0x21a): undefined reference to `boost::system::get_system_category()' timer3.cpp:(.text+0x224): undefined reference to `boost::system::get_posix_category()' timer3.cpp:(.text+0x22e): undefined reference to `boost::system::get_posix_category()' timer3.cpp:(.text+0x238): undefined reference to `boost::system::get_system_category()' /tmp/ccNQAhKx.o: In function `boost::asio::error::get_system_category()': timer3.cpp:(.text._ZN5boost4asio5error19get_system_categoryEv[boost::asio::error::get_system_category()]+0x7): undefined reference to `boost::system::get_system_category()' /tmp/ccNQAhKx.o: In function `boost::system::error_code::error_code()': timer3.cpp:(.text._ZN5boost6system10error_codeC1Ev[boost::system::error_code::error_code()]+0x10): undefined reference to `boost::system::get_system_category()' collect2: ld returned 1 exit status then I also link the boost_system: g++ timer3.cpp -lboost_thread -lboost_system but g++ can not find the libboost_system althoght we have these file in the /usr/lib folder: /usr/lib/libboost_system-gcc42-mt-1_35.so /usr/lib/libboost_system-gcc42-mt-1_35.so.1.35.0 and these files in the /usr/local/lib : /usr/local/lib/libboost_system-gcc42-mt-1_35.so /usr/local/lib/libboost_system-gcc42-mt-1_35.so.1.35.0 /usr/local/lib/libboost_system-gcc42-mt.so can anyone help me that whats wrong with me? and is the boost_system installed properly? -- View this message in context: http://www.nabble.com/Problem-with-boost.asio-tp19232020p19232020.html Sent from the Boost - Users mailing list archive at Nabble.com.

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how to run listener socket in a separate thread
by lakers fan 30 Aug '08

30 Aug '08

Hello, I have a udp listener socket, I want that to run in a separate thread. Just listen for incoming messages and pass the message to message handler. I checked the tutorial, it shows boost::asio::io_service io_service; udp_server server(io_service); io_service.run(); I see the run() method running in a loop. Then how do I stop the service from some other thread?. Any help would be greatly appreciated. Thanks, Bharani _________________________________________________________________ Talk to your Yahoo! Friends via Windows Live Messenger. Find out how. http://www.windowslive.com/explore/messenger?ocid=TXT_TAGLM_WL_messenger_ya…

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[asio] local socket Connections via iostream
by Alex Adranghi 30 Aug '08

30 Aug '08

Hi, I cannot figure out what to supply as arguments to instantiate local::stream_protocol::iostream (or run iostream.connect on a blank constructor) to establish a connection. I've tried endpoints and string of the socket path (although I have no clue whether I should be sending something else as a second parameter?). With local sockets I've not been able to find anything useful online and the documentation on the boost website is in generic template form. Help / links appreciated. Cheers, Alex

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1.36: missing boost/integer/endian.hpp?
by Pfligersdorffer, Christian 30 Aug '08

30 Aug '08

Why was it removed? Does anyone know? Wondering, -- Christian Pfligersdorffer Software Engineering http://www.eos.info

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[Boost.FileSystem] Broken link in documentation + errornous example
by Mika Heiskanen 30 Aug '08

30 Aug '08

Hello, In the documentation at http://www.boost.org/doc/libs/1_36_0/libs/filesystem/doc/index.htm in section named "Using the library" there is a broken link named "example directory" (404 Not Found). Also, the example program http://www.boost.org/doc/libs/1_36_0/libs/filesystem/example/simple_ls.cpp uses dir_itr->filename() but when I do grep -r filename /usr/local/include/boost-1_35/boost/filesystem I get no matches. I ended up using dir_itr->path().leaf() instead. --> Mika Heiskanen / FMI

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Re: [Boost-users] Multi-index container (Modifying non-unique key in the container)
by JOAQUIN M. LOPEZ MUÑOZ 29 Aug '08

29 Aug '08

(Excuse the slow pace of this thread, I've been on vacation with little access to the Internet). ________________________________ De: boost-users-bounces(a)lists.boost.org [boost-users-bounces(a)lists.boost.org] En nombre de Ramesh [rramesh1(a)gmail.com] Enviado el: jueves, 21 de agosto de 2008 0:17 Para: boost-users(a)lists.boost.org Asunto: Re: [Boost-users] Multi-index container (Modifying non-unique key in the container) On Wed, Aug 20, 2008 at 8:02 AM, JOAQUIN M. LOPEZ MUÑOZ <joaquin(a)tid.es<mailto:joaquin@tid.es>> wrote: Yes, but DataMap seems to *replicate* the keys that are already present in A. Cannot you just have the following? typedef multi_index_container< A*, indexed_by< ordered_unique< tag <Key1>, BOOST_MULTI_INDEX_MEMBER(A,std::string,Key1)>, ordered_non_unique< tag<Key2>,BOOST_MULTI_INDEX_MEMBER(A,long,Key2)>, ordered_unique< tag<Key3>,BOOST_MULTI_INDEX_MEMBER(A,long,Key3)> > > tDMap; [...] > > If I would remove the keys the map would just hold pointers and I wouldnt be able to > do lookups based on the keys (to retrieve pointers to objects based on keys) if I wouldnt > pair the pointers with they keys in the Map - thats why I have the keys in the map, please > correct me if am wrong. You can use the members of the pointed to objects of type A as keys of your container. This is discussed in detail at: http://www.boost.org/libs/multi_index/doc/reference/key_extraction.html#cha… In particular, I think that the tDMap definition I gave above should work directly. Please report back if this is not the case. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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