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serialization of derived classes...
by Filip Peters 07 Jul '05

07 Jul '05

Hi list, I'm using the boost::serialization lib to archive classes in a VC7.1 program. I have a class C, derived from B, derived from (abstract) A now, in serialisation of C, I did: ar & boost::serialization::make_nvp( "baseobject", boost::serialization::base_object<B>( t ) ); This seems to give a memory leak on closing the application. So I tried the following 2 lines: ar & boost::serialization::make_nvp( "baseobject", boost::serialization::base_object<A>( t ) ); ar & boost::serialization::make_nvp( "baseobject2", boost::serialization::base_object<B>( t ) ); and this seemed to work.... What is the correct way of saving C (derived from B which is derived from A)? It seems a bit strange to me that i have to call serialization of A in the ser. of C. Shouldn't B take care of this? thanks, Filip Peters __________________________________ Yahoo! Mail Stay connected, organized, and protected. Take the tour: http://tour.mail.yahoo.com/mailtour.html

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Boost Threads and MFC AfxLoadLibrary
by Greg Kogut 07 Jul '05

07 Jul '05

Hi, I've created a very simple threading program, basically a modification of one of the boost examples. I've successfully compiled and run the program in both Linux and Windows. My next step was to embed the code in a Windows MFC DLL. Again, very simply. A few lines of code. The DLL compiles correctly. However, MFC's AfxLoadLibrary returns FALSE when I try to load the library. Some source code: axisGrabThreadBody grabber(&myimage); //a structure containing code to put in thread boost::thread grab(grabber); //create the boost thread grab.join(); //bind the thread The above fails when trying to load via AfxLoadLibrary. This is before the code is run. It's just when trying to dynamically load at runtime. However: AFX_MANAGE_STATE(AfxGetStaticModuleState()); axisGrabThreadBody grabber(&myimage); //a structure containing code to put in thread //boost::thread grab(grabber); //create the boost thread //grab.join(); //bind the thread Now AfxLoadLibrary correctly loads the DLL. Why is this? Again, the code is not being run. I'm using the latest stable release of Boost, and running Windows XP. Using VC++ 7. Vastly prefer gcc and Emacs to VC++ 7. Any ideas? Thanks, Greg

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Re: [Boost-users] boost::lambda::bind question
by Vishnevetsky, Eugene (IT) 07 Jul '05

07 Jul '05

I came across this problem in the real project where I don't control the class that corresponds to class Y of the example, so I can't change the signature of the member function. I could write a wrapper function that takes Y*, but after some point the code with a simple 'for' loop becomes cleaner and more readable than the one using lambda. If this problem is not a bug, but an inherent limitation of the lambda library or its current implementation, it would be nice if it is mentioned in the documentation. Thanks, Eugene Vishnevetsky Roman Krylov wrote: Perhaps the only solution here is to use Y* instead of Y& with corresponding modifications; this way there is no need for var() or smth similar. Why not? Vishnevetsky, Eugene (IT) wrote: >Is it possible to use boost::ref() or boost::lambda::var() of an >abstract class as a parameter to boost::lambda::bind()? >It seems that compiler attempts to instantiate an object of that >abstract class. >Example: > >----------------- >using namespace boost; >using namespace boost::lambda; >class Y >{ >public: > virtual void foo() = 0; > void foo2 (){ } >}; >class Z : public Y >{ >public: > void foo(){} >}; > >class TT >{ >public: > void test( Y& y ) { y.foo2(); } >}; > >int main() >{ > std::vector<TT> xt; > Z z; > Y &y = z; > std::for_each (xt.begin(), xt.end(), bind(&TT::test,_1, >ref(y))); > return 0; >} >---------------------- > >And Error message from g++ (GCC) 3.2.3: > >--------------------------------- >/boost/tuple/detail/tuple_basic.hpp: In instantiation of >`boost::tuples::cons<Y, boost::tuples::null_type>': >/boost/tuple/detail/tuple_basic.hpp:326: instantiated from >`boost::tuples::cons<boost::tuples::null_type, boost::tuples::cons<Y, >boost::tuples::null_type> >' >/boost/tuple/detail/tuple_basic.hpp:326: instantiated from >`boost::tuples::cons<void (TT::*const)(Y&), >boost::tuples::cons<boost::tuples::null_type, boost::tuples::cons<Y, >boost::tuples::null_type> > >' >/boost/lambda/detail/lambda_functor_base.hpp:151: instantiated from >`boost::lambda::detail::has_null_type<boost::tuples::cons<void >(TT::*const)(Y&), boost::tuples::cons<boost::tuples::null_type, >boost::tuples::cons<Y, boost::tuples::null_type> > > >' >/boost/lambda/detail/lambda_functor_base.hpp:229: instantiated from >`boost::lambda::detail::deduce_non_ref_argument_types<boost::tuples::tu >p >le<void (TT::*const)(Y&), const >boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, Y&, >boost::tuples::null_type, boost::tuples::null_type, >boost::tuples::null_type, boost::tuples::null_type, >boost::tuples::null_type, boost::tuples::null_type, >boost::tuples::null_type>, boost::tuples::null_type>' >/boost/lambda/detail/lambda_functor_base.hpp:412: instantiated from >`boost::lambda::lambda_functor_base<boost::lambda::action<3, >boost::lambda::function_action<3, boost::lambda::detail::unspecified> >>, boost::tuples::tuple<void (TT::*const)(Y&), const >boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, Y&, >boost::tuples::null_type, boost::tuples::null_type, >boost::tuples::null_type, boost::tuples::null_type, >boost::tuples::null_type, boost::tuples::null_type, >boost::tuples::null_type> >::sig<boost::tuples::null_type>' >/boost/lambda/detail/lambda_functors.hpp:135: instantiated from >`boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost : >:lambda::action<3, boost::lambda::function_action<3, >boost::lambda::detail::unspecified> >, boost::tuples::tuple<void >(TT::*const)(Y&), const >boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, Y&, >boost::tuples::null_type, boost::tuples::null_type, >boost::tuples::null_type, boost::tuples::null_type, >boost::tuples::null_type, boost::tuples::null_type, >boost::tuples::null_type> > >' >lamtest.cpp:35: instantiated from here >/boost/tuple/detail/tuple_basic.hpp:320: cannot declare field >`boost::tuples::cons<Y, boost::tuples::null_type>::head' >to be >of type `Y' >/boost/tuple/detail/tuple_basic.hpp:320: >because the following virtual functions are abstract: >lamtest.cpp:12: virtual void Y::foo() >---------------------------------------- > >Thanks, > >Eugene Vishnevetsky >-------------------------------------------------------- > >NOTICE: If received in error, please destroy and notify sender. Sender does not waive confidentiality or privilege, and use is prohibited. > >_______________________________________________ >Boost-users mailing list >Boost-users(a)lists.boost.org >http://lists.boost.org/mailman/listinfo.cgi/boost-users <http://lists.boost.org/mailman/listinfo.cgi/boost-users> > > > -------------------------------------------------------- NOTICE: If received in error, please destroy and notify sender. Sender does not waive confidentiality or privilege, and use is prohibited.

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johnson_all_pairs_shortest_paths under MSVC 6.0?
by Vivid Yang 07 Jul '05

07 Jul '05

Hi, Does anybody has experience in applying johnson_all_pairs_shortest_paths under WINDOWS? Examples would help me a lot. I have difficulties in compiling the johnson_all_pairs_shortest_paths example in the library: example/johnson-eg.cpp The code D[id2[*u]-1][id2[*v]-1] = get(d, *v) + get(h, *v) - get(h, *u); has error: "subscript requires array or pointer type" Thanks a lot. Vivid

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[signals] Disconnecting slots
by Staal, J.J. (Joes) 07 Jul '05

07 Jul '05

In the docs for signals, an example is given for disconnecting slots: void foo(); void bar(); signal<void()> sig; sig.connect(&foo); sig.connect(&bar); // disconnects foo, but not bar sig.disconnect(&foo); When I try this with MSV 7.1, I get an compiler error: error C2664: 'boost::signal0<R,Combiner,Group,GroupCompare,SlotFunction>::disconnect' : cannot convert parameter 1 from 'void (__cdecl *)(void)' to 'const boost::signal0<R,Combiner,Group,GroupCompare,SlotFunction>::group_type &' with [ R=boost::detail::function_traits_helper<boost::add_pointer<void (void)>::type>::result_type, Combiner=boost::last_value<void>, Group=int, GroupCompare=std::less<int>, SlotFunction=boost::function<void (void)> ] and [ R=boost::detail::function_traits_helper<boost::add_pointer<void (void)>::type>::result_type, Combiner=boost::last_value<void>, Group=int, GroupCompare=std::less<int>, SlotFunction=boost::function<void (void)> ] My question is, are the docs incorrect, or am I doing something wrong? Regards, Joes. This e-mail and its contents are subject to the DISCLAIMER at http://www.tno.nl/disclaimer/email.html

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boost::variant and SGI's compose1 cause constness error
by junkmail.hoefling＠arcor.de 07 Jul '05

07 Jul '05

Hi there, I have a problem using boost::variant. I want apply_visitor to go through a list of pairs whose first type is a variant. Using compose1 and select1st from the SGI extensions to the STL yields a constness error. The problem is illustrated by the attached code which shoud be compiled with the g++ (the SGI extensions are here available via __gnu_cxx). What's wrong? Is it my fault using the library or is it a missing const version in apply_visitor_delayed_t()? Thanks a lot for any hints! Best, Erwin

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circular buffer and gcc 4.0.0
by Vincent Torri 07 Jul '05

07 Jul '05

Hello, I need to use gcc 4.0 and circular buffer. But this latter seems unusuable with gcc 4.0. It gives a lots of error messages. Here is the 2 irst error messages: in debug.hpp: /home/torri/local/include/boost-1_33/boost/circular_buffer/debug.hpp:60: error: invalid use of undefined type 'const struct boost::cb_details::cb_iterator_base' /home/torri/local/include/boost-1_33/boost/circular_buffer/debug.hpp:22: error: forward declaration of 'const struct boost::cb_details::cb_iterator_base' the 2 classes in debug.hpp are cross-referenced. It seems that the forward declaration is not sufficient for gcc 4.0. in base.hpp: /home/torri/local/include/boost-1_33/boost/circular_buffer/base.hpp:139: error: using typedef-name 'boost::circular_buffer<T, Alloc>::iterator' after 'struct' /home/torri/local/include/boost-1_33/boost/circular_buffer/base.hpp:105: error: 'boost::circular_buffer<T, Alloc>::iterator' has a previous declaration here /home/torri/local/include/boost-1_33/boost/circular_buffer/base.hpp:139: error: friend declaration does not name a class or function gcc 4.0 doesn't like the 'struct' word. Putting the 'class' word instead of struct gives error too: /home/torri/local/include/boost-1_33/boost/circular_buffer/base.hpp:139: error: a class-key must be used when declaring a friend /home/torri/local/include/boost-1_33/boost/circular_buffer/base.hpp:139: error: friend declaration does not name a class or function Does someone see solutions for these problems ? Jan: it would be great if you try to finish circular buffer :) thank you Vincent Torri

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BGL - Multiple graphs on the same data-structure.
by sr kumar 07 Jul '05

07 Jul '05

Hi, My application needs to have multiple graphs overlayed on the same set of data. Looks like used bundled properties would be very attractive. Since the data-set is likely to be large and the graphs will have to coexist, I'd like to build graphs of pointers to the base data. However, I am having trouble figuring out how to store pointers to the data structures within an adjacency_list. Any suggestions/pointers to examples would be much appreciated. -sr

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BGL: Brandes betweenness and exterior properties
by Todd A. Gibson 07 Jul '05

07 Jul '05

Hello, I am working with brandes_betweenness_centrality in the BGL and am having difficulty correctly constructing the syntax for retrieving an EdgeCentralityMap using exterior properties. I can successfully invoke the function using bundled properties: struct EdgeAttrs { unsigned int index; double weight; }; template<class GraphType> boost::python::list betweenness_centrality(GraphType& g) { typedef typename GraphType::edge_descriptor Edge; std::vector<float> centmap(num_vertices(g)); std::vector<float> edgecent(num_edges(g)); brandes_betweenness_centrality (g, centrality_map(make_iterator_property_map(centmap.begin(), boost::get(vertex_index, g), float())) .edge_centrality_map(make_iterator_property_map(edgecent.begin(), boost::get(&EdgeAttrs::index, g),float())) .weight_map(boost::get(&EdgeAttrs::weight, g))); ... Among my attempts, here's a typical one that won't compile: typedef typename std::map<Edge, double> EdgeMap; EdgeMap myedges; //... boost::associative_property_map< EdgeMap > edge_assoc_map(myedges); brandes_betweenness_centrality(g, ... .edge_centrality_map(edge_assoc_map) ...) Can someone enlighten me? Thanks, -TAG

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in_edges for a directedS adjacency_list
by sr kumar 07 Jul '05

07 Jul '05

Hi, Is there a reason that the in_edges are not being maintained for a directedS adjacency_list? A quick look through implementations of boost::detail::add_edge(*) indicates correct maintainance for a bidirectional case, and reuse of the out_edges for the undirected case. I'm hopefully not missing something obvious to more enlightened souls and would appreciate any ideas to get the in_edges correctly for a directedS adjacency_list. thanks, -sr

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