February 2007 - Boost-users - lists.preview.boost.org

[multi_array] operator= requires resize - why?
by Markus Werle 04 Jun '12

04 Jun '12

Hi! IMHO the behaviour of operator= for multi_array is a little bit broken. A lot of preconditions required: template <typename ConstMultiArray> multi_array_ref& operator=(const ConstMultiArray& other) { [...] // make sure the dimensions agree assert(other.num_dimensions() == this->num_dimensions()); assert(std::equal(other.shape(),other.shape()+this->num_dimensions(), this->shape())); Besides the fact that I get mad about asserts instead of exceptions (please change this to a way users may choose) why do we have such an odd behaviour here? >From page 1, line 3 of the docs I cite: "The interface design is in line with the precedent set by the C++ Standard Library containers" - this is not true for operator=, since std::<container>::operator= works fine for me all the time _without_ any resize. Could we please change the behaviour of multi_array::operator= to take care of resize where in need to? IMHO operator= should result in a true copy ignoring previous state. Markus

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Design for boost::serialization of STL iterators.
by Carlo Wood 23 May '09

23 May '09

On Sat, Mar 11, 2006 at 11:45:36PM +0200, Peter Dimov wrote: > Carlo Wood wrote: > > > 1) WHY does boost::serialization not support serialization > > of iterators? > > It's very hard, if not impossible, in general. It is either impossible or possible. When it is possible, it can't be hard :p I think that at the moment of serialization, the actual container needs to be known. So, only concentrating on the syntax of the code that serializes an iterator, the following cannot work: ar & iter; However, the container will be known at that point (or at least, we might as well assume that). Therefore, I could imagine a syntax like: ar & foobar(container, iter); where 'foobar' is some template function (that will be part of boost::serialization in the future). Lets start with the last one (have to start somewhere). In order to deserialize the iterator (and taken into account that we already have the container) -- which makes me think that it might be better to pass a functor to operator& above. In other words, (at least for writing), use: template<class Container> struct Foobar { Foobar(Container const&, typename Container::const_iterator& iter) : M_container(container), M_iter(iter); private: Container const& M_container; Container::const_iterator& M_iter; }; and then assign to M_iter, whatever we find in M_container. > If you have access to the container to which the iterator i refers: > > a) if the container is a map, you can serialize i->first, then on > deserialization look up the key in the map using .find(); > > b) if the container is a sequence, and it has the same contents on > deserialization as it does on serialization, you can serialize the index of > the element - distance( c.begin(), i ). I don't think that it is a requirement that the whole container has to be read: either it's a map or set, in which case later insertions will not invalidate the container, or it is a vector, in which case we use an index, from which we can construct the end iterators before the whole container is reconstructed. Therefore, the following syntax can work imho: ar & FooBar(container, iter); Would you agree? There are a zillion questions and implementation details open - but I'd like to get anyones feedback about this type of interface for iterators before continuing. Current questions: What is a good name for Foobar? Am I right when I think that Foobar needs to be declared in boost::serialization? Now the hard part (for me) is that part that involves the internals of the boost library. At the moment one tries to serialize an iterator, it is possible (though not necessarily) that the object that the iterator points to is already serialized. In the case that we are dealing with an associative container (map or set etc), we don't want to store the contents of the object (or key part, in the case of a map) again: I'd like to just store that once, and store a reference in the archive at the other place. How can I make the library store an object only the first time and the store a reference the second time? This would be for an object of arbitrary type thus. I think that it is only feasible to do this when it's actually the same object (same memory address), which is the case; but while storing the object element of the container, the address of it isn't stored as well, is it? Is there a way to make: std::set<SomeData> s; [...] ar << s; Store the address of s (&s) along with the contents of s? And would that then automatically cause the library to not store that same object again when I do: std::set<SomeData>::iterator iter = s.find(...); [...] ar << *iter; Because then, &*iter would again be the same memory address as what was stored before. -- Carlo Wood <carlo(a)alinoe.com>

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[BGL] citing the Boost Graph Library
by Alejandro Marcos Aragón 06 May '09

06 May '09

Can anyone point me how to cite the Boost Graph Library in a paper? Is there any information in the boost website? Thank you all, Alejandro Aragón

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Boost Graph Library and Boehm Garbage Collector
by FBSL 08 Sep '08

08 Sep '08

Hello I am having trouble to garbage-collect adjacency_list<>. I have instanciated it with correctly garbage-collected vectors and lists (I have copied vecS and listS definitions, and added Boehm GC's default allocator so that they are garbage-collected). In my application I need to dynamically allocate many graphs, but it does not work, there is a (big) memory leak. Unfortunately, there is no template argument in adjacency_list<> to specify Boehm GC's allocator. Does anyone have a hint ? Snippet code "main.cpp" follows, compiled with Boost Graph Library 1.32, Boehm GC 6.4 and G++ 3.3.5, with command line : $ g++ -o main main.cpp -lgc -lgccpp -- #include <boost/graph/adjacency_list.hpp> #include <gc/gc_allocator.h> #include <gc/gc_cpp.h> #include <iostream> #include <vector> #include <list> using namespace std; using namespace boost; namespace boost { struct collected_vecS {}; struct collected_listS {}; template <class ValueType> struct container_gen<collected_vecS, ValueType> { typedef vector<ValueType,gc_allocator<ValueType> > type; }; template <class ValueType> struct container_gen<collected_listS, ValueType> { typedef list<ValueType,gc_allocator<ValueType> > type; }; template <> struct parallel_edge_traits<collected_vecS> { typedef allow_parallel_edge_tag type; }; template <> struct parallel_edge_traits<collected_listS> { typedef allow_parallel_edge_tag type; }; namespace detail { template <> struct is_random_access<collected_vecS> { enum { value = true }; typedef true_type type; }; } } typedef adjacency_list<collected_vecS, collected_vecS, directedS, no_property, no_property, no_property, collected_listS> graph; int main() { // leaks... while(true){ graph * g=new (UseGC) graph; for(unsigned int i=0; i<100; ++i){ add_vertex(*g); } for(unsigned int i=0; i<100; ++i){ for(unsigned int j=0; j<100; ++j){ add_edge(i,j,*g); } } } }

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[statechart] history transitions make state-local-storage "un-cool"
by Mick Hollins 26 Jun '08

26 Jun '08

Apologies if this has been discussed before, but I couldn't find any mention of it: I am currently using the history facility of boost::fsm. I've discovered that when I re-enter a state, X, via a history transition I don't actually re-enter the same instance of X that I was in before, but instead enter a newly constructed instance of X. I just checked the UML spec regarding history transitions and it says that "Any necessary entry actions are performed", so given that boost::fsm uses constructors to represent entry actions I guess a new instance of X has to be constructed to ensure UML compliance. My actual concern is the effect this has on the "coolness" of state-local-storage (see http://boost-sandbox.sourceforge.net/libs/statechart/doc/faq.html#Whats_so_…) It seems to me that state-local-storage, which I agree is generally cool, is particularly un-cool (and bug-inducing) in the presence of history transitions. I'm not sure what a good alternative is, but just thought I'd raise the discussion. cheers, mick PS: does the history facility display the same semantics in boost::statechart? I plan to move to statechart real soon now ...

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Re: [Boost-users] cross compiling boost for ARM
by Hughes, James 12 Aug '07

12 Aug '07

> -----Original Message----- > From: boost-users-bounces(a)lists.boost.org > [mailto:boost-users-bounces@lists.boost.org] On Behalf Of remi > Sent: 05 January 2007 14:44 > To: boost-users(a)lists.boost.org > Subject: [Boost-users] cross compiling boost for ARM > > > hi! > > I want to cross compile boost for an ARM processor. > For a pxa 270. but when i try to cross compile boost with > arm-linux-g++ , it dosen't work ... a proble with jam... > > everyone can help me? > > Thank you > > BEST REGARDS > > Rémi bjam "-sGCC_ROOT_DIRECTORY=/opt/montavista/mobilinux/devkit/arm/iwmmxt_le" "-sGCC=iwmmxt_le-gcc" "-sGXX=iwmmxt_le-g++" <location for libs> Obviously you would need to change the location namd names of the compile tools to whatever you are using. James This message (including any attachments) contains confidential and/or proprietary information intended only for the addressee. Any unauthorized disclosure, copying, distribution or reliance on the contents of this information is strictly prohibited and may constitute a violation of law. If you are not the intended recipient, please notify the sender immediately by responding to this e-mail, and delete the message from your system. If you have any questions about this e-mail please notify the sender immediately.

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[Serialization] Problem serialization of derived classes
by Andreas Willich 09 Aug '07

09 Aug '07

Hi there! I have a problem with the code in the attachment. I followed the documentation and the examples, but I did not get the code to work. Gcc produces a lot of failures that something is already instantiated in header files of the serialization library. Has someone a idea what I am doing wrong? My gcc version is 4.1.1-r3 and I am working on a gentoo x86 box. Andreas Willich

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[lambda][1.33.1] Lambda warnings after installing VS2005 SP1
by john.wismar＠autozone.com 01 Aug '07

01 Aug '07

I have just installed Service Pack 1 for VS2005, and am now getting a warning in some code using lambda::bind. There wasn't a warning previously, but I don't know if the issue is due to an update to the C++ standard library, a legitimate warning that they weren't flagging before, or a spurious warning. It looks like the issue is that I'm passing a function pointer, to bind. Is this a warning I should just ignore, or is this a legitimate issue? Thanks for your help! Here's a sample app, followed by the warnings I'm seeing. #include <boost/lambda/bind.hpp> using boost::lambda::bind; using boost::lambda::_1; #include <vector> #include <map> #include <algorithm> int main() { enum choice { select, reject }; std::vector<long> questions; std::map<long, choice> answers; std::transform(questions.begin(), questions.end(), std::inserter(answers, answers.begin()), bind(std::make_pair<long, choice>, _1, select)); return 0; } c:\boost\boost\lambda\detail\lambda_traits.hpp(389) : warning C4180: qualifier applied to function type has no meaning; ignored c:\boost\boost\lambda\detail\lambda_traits.hpp(458) : see reference to class template instantiation 'boost::lambda::detail::bind_traits<T>' being compiled with [ T=std::pair<long,main::choice> (long,main::choice) ] c:\temp\lambda_warning_test\lambda_warning_test.cpp(20) : see reference to class template instantiation 'boost::lambda::detail::bind_tuple_mapper<T0,T1,T2,T3,T4,T5,T6,T7,T8,T9>' being compiled with [ T0=std::pair<long,main::choice> (long,main::choice), T1=boost::lambda::placeholder1_type, T2=const main::choice, T3=boost::tuples::null_type, T4=boost::tuples::null_type, T5=boost::tuples::null_type, T6=boost::tuples::null_type, T7=boost::tuples::null_type, T8=boost::tuples::null_type, T9=boost::tuples::null_type ] -------------------------------- John Wismar john.wismar(a)autozone.com

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BGL: INTERNAL COMPILER ERROR in VC7.1
by Yariv Tal 10 Jun '07

10 Jun '07

This one was already posted by Nicholas Burlett awhile back (see http://lists.boost.org/MailArchives/boost-users/msg06534.php) but I have some new info that may help. The problem: ========= When compiling code that uses the boost.graph library the VC7.1 compiler shouts: c:\boost_1_32_0\boost\mpl\aux_\preprocessed\plain\apply_wrap.hpp(48) : fatal error C1001: INTERNAL COMPILER ERROR As Nicholas already noted, this seems to be due to some compiler problem with the boost.graph out_edge_iterators since it is caused by the following lines in my code: (FilteredGraphGenerator::FilteredGraph is a typedef of a boost::filtered_graph) typedef boost::graph_traits<FilteredGraphGenerator::FilteredGraph> ::out_edge_iterator oedge_iterator; oedge_iterator edgesItr, edgesEnd; boost::tie(edgesItr, edgesEnd) = boost::out_edges(itr->first, m_g.m_filteredGraph); while (edgesItr != edgesEnd) { // do anything! } In fact, it seems to be related to the operator!= between iterators (if the while loop is commented out it compiles). How ever, the error persists even after changing the operator!= to operator== : while (edgesItr == edgesEnd) { // do anything! } ========================================================================== Some findings: =========== * We used to use boost_1_30_0 and the code used to compile PERFECTLY. The problem only appeared after migrating to boost_1_32_0. * Calling directly to the "equal" function in iterator_core_access instead of the operator== works. typedef boost::graph_traits<FilteredGraphGenerator::FilteredGraph> ::out_edge_iterator oedge_iterator; oedge_iterator edgesItr, edgesEnd; boost::tie(edgesItr, edgesEnd) = boost::out_edges(itr->first,m_g.m_filteredGraph); while (boost::iterator_core_access::equal(edgesItr, edgesEnd, boost::mpl::true_())) { // do somthing } * The error message location is at the mpl::apply_wrap2 function. Any relation to the mpl::apply2 function used for declaring the operator== in the BOOST_ITERATOR_FACADE_INTEROP_HEAD macro? Have these functions changed since v1.30.0?

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[BGL-Python] __len__ and __iter__ for property maps
by George Sakkis 21 May '07

21 May '07

I'm trying to build BGL-Python from SVN. I managed to build it successfully on Windows (VC 8.0) but I'm having problems with gcc 3.4 on Linux; although it does compile, it doesn't expose in Python two property map methods, __len__ and __iter__. I think I narrowed it down to the non-selection of a template specialization: // boost/graph/python/property_map.hpp namespace boost { namespace graph { namespace python { namespace detail { / * skip other stuff */ template<typename Class, typename T, typename IndexMap> void property_map_extras(Class& pm, type<vector_property_map<T, IndexMap> >) { pm.def("__len__", &py_vector_property_map_length<T, IndexMap>); typedef typename std::vector<T>::iterator value_iterator; simple_python_iterator<value_iterator>::declare("ValueIterator"); pm.def("__iter__", &py_vector_property_map_values<T, IndexMap>); } template<typename Class, typename PropertyMap> inline void property_map_extras(Class&, type<PropertyMap>) { } } // end namespace detail */ So for __len__ and __iter__ to be included, the first overloading of property_map_extras must be called. That's what happens with VC 8.0 (in fact I can remove the second empty function and compiles just fine), but gcc selects the second one. Can anyone help and/or reproduce it ? Thanks, George

2 1

read_graphviz question
by Jeffrey Holle 26 Apr '07

26 Apr '07

I'm using the post 1.31.1 version of boost, which has a much nicer read_graphviz function. I'm wondering if there is a way to "ignore" unwanted properties, something akin to sending them to /dev/null. My present experience is that if an unexpected property is found, an exception is thrown. Is there a way to express that a given property is to be ignored? Better yet, is there a way to say that all unexpected properties are to be ignored?

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[boost::wave] MSVC 8 warning
by Ovanes Markarian 27 Mar '07

27 Mar '07

Hello, I would like to address this issue to boost::wave authors. First of all great lib! Many thanks! During the compilation with MSVC8 Express Edition I get a warning: c:\boost\include\boost-1_33_1\boost\wave\cpp_context.hpp(112) : warning C4355: 'this' : used in base member initializer list c:\boost\include\boost-1_33_1\boost\wave\cpp_context.hpp(106) : while compiling class template member function 'boost::wave::context<IteratorT,LexIteratorT>::context(const std::_String_iterator<_Elem,_Traits,_Alloc> &,const std::_String_iterator<_Elem,_Traits,_Alloc> &,const char *,const TraceT &)' with [ IteratorT=token_groups::str_iter_type, LexIteratorT=token_groups::lex_iter_type, _Elem=char, _Traits=std::char_traits<char>, _Alloc=std::allocator<char>, TraceT=boost::wave::context_policies::default_preprocessing_hooks ] My typedefs look like: typedef wave::cpplexer::lex_token<> token_type; typedef wave::cpplexer::lex_iterator<token_type> lex_iter_type; typedef std::string::iterator str_iter_type; typedef wave::context<str_iter_type, lex_iter_type> context_type; typedef context_type::iterator_type ctx_iter_type; Is there any chance that this warning will be suppressed in the next release, since it is a little bit annoying. I can't do anything about it as a user of wave and I also try to follow the rule to compile clean without warnings. Many thanks and With Kind Regards, Ovanes Markarian

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[BGL] Reading GraphML
by Jens Müller 25 Mar '07

25 Mar '07

I tried to read a GraphML file using Douglas' code and the following: std::auto_ptr<boost::dynamic_property_map> string2string_gen(const std::string& name, const boost::any&, const boost::any&) { typedef std::map<std::string,std::string> map_t; typedef boost::associative_property_map< std::map<std::string, std::string> > property_t; map_t* mymap = new map_t(); // hint: leaky memory here! property_t property_map(*mymap); std::auto_ptr<boost::dynamic_property_map> pm( new boost::detail::dynamic_property_map_adaptor<property_t>(property_map)); return pm; } int main(int argc, char* argv[]){ // create a typedef for the Graph type using namespace boost; typedef boost::adjacency_list<vecS, vecS, directedS> Graph; Graph g; std::ifstream input(argv[1]); boost::dynamic_properties properties(&string2string_gen); typedef graph_traits<Graph>::vertex_descriptor Node; typedef property_map<Graph, vertex_index_t>::type NodeID_Map; NodeID_Map node_id = get(vertex_index, g); boost::read_graphml(input, g, properties); } but when running it I get: Unrecognized attribute `xmlns' of element `graphml'. Ignoring... Unrecognized attribute `xmlns:y' of element `graphml'. Ignoring... Unrecognized attribute `xmlns:xsi' of element `graphml'. Ignoring... Unrecognized attribute `xsi:schemaLocation' of element `graphml'. Ignoring... Unrecognized attribute `yfiles.type' of element `key'. Ignoring... Unrecognized attribute `yfiles.type' of element `key'. Ignoring... Unrecognized element `y:ShapeNode' Unrecognized element `y:Geometry' Unrecognized element `y:Fill' Unrecognized element `y:BorderStyle' Unrecognized element `y:NodeLabel' Unrecognized element `y:Shape' terminate called after throwing an instance of 'boost::bad_any_cast' what(): boost::bad_any_cast: failed conversion using boost::any_cast /bin/sh: line 1: 31380 Abgebrochen ./src/graphml2 Core0bis10_1000.graphml The file contains nodes like this (what a bloat ...): <node id="n1"> <data key="d0" > <y:ShapeNode > <y:Geometry x="2.457598996954175" y="498.06375265283157" width="10.0" height="10.0"/> <y:Fill color="#FF0000" transparent="false"/> <y:BorderStyle type="line" width="1.0" color="#000000" /> <y:NodeLabel x="3.0" y="3.0" width="4.0" height="4.0" visible="true" alignment="center" fontFamily="Dialog" fontSize="12" fontStyle="plain" textC olor="#000000" hasBackgroundColor="false" hasLineColor="false" modelName="internal" modelPosition="c" autoSizePolicy="content"></y:NodeLabel> <y:Shape type="rectangle"/> </y:ShapeNode> </data> </node> I am not even really interested in the d0 properties ... What can I do?

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[Serialization] issue with portable_binary_oarchive
by Dan Leibovich 16 Mar '07

16 Mar '07

Hi, I am trying to use the portable binary archive example. I need to serialize only integers and strings. I tried it on linux and solaris5.8. The result binary stream is not the same and deserialization fails. I used hex viewer and notice that the files are very similar except for some few differences which results from endienness issues. Can it be that the metadata is written differently on each platform. This is happens when I serialize derived class through a pointer to base class. (I used BOOS_CLASS_EXPORT) Below you will find a test case. It produce differ output on linux and solaris. Am I missing something? Thanks in advance Dan Leibovich #include <fstream> #include "portable_binary_oarchive.hpp" #include <boost/serialization/base_object.hpp> #include <boost/serialization/export.hpp> class Base { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & x; } protected: int x; public: Base() {} ; Base(int x_) : x(x_) {} ; virtual void foo() {} ; }; class Derived1 : public Base { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & boost::serialization::base_object<Base>(*this); ar & y; } protected: int y; public: Derived1() {} ; Derived1(int x_, int y_) : Base(x_), y(y_) {} ; virtual void foo() {x++;} }; class Derived2 : public Base { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & boost::serialization::base_object<Base>(*this); ar & z; } protected: bool z; public: Derived2() {} ; Derived2(int x_) : Base(x_), z(true) {} ; virtual void foo() {x--;} }; class Container { Base* b1 ; Base* b2 ; friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & b1; ar & b2 ; } public: Container() {} ; Container(int x, int y) { b1 = new Derived1(x,y) ; b2 = new Derived2(x) ; } }; BOOST_CLASS_EXPORT(Derived1) ; BOOST_CLASS_EXPORT(Derived2) ; int main() { std::ofstream ofs("filename"); const Container c(1,2) ; portable_binary_oarchive oa(ofs); oa << c; }

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[statechart] - problem with sc::transition<> -> invalid use of 'boost::statechart::detail::no_context::no_function [with Event = jm::ffcp::ev_init]' to form a pointer-to-member-func
by Oliver.Kowalke＠qimonda.com 15 Mar '07

15 Mar '07

Hello, I get following error: /opt/boost/include/boost-1_33_1/boost/statechart/transition.hpp:33: error: invalid use of 'boost::statechart::detail::no_context::no_function [with Event = jm::ffcp::ev_init]' to form a pointer-to-member-function /opt/boost/include/boost-1_33_1/boost/statechart/transition.hpp:33: note: a qualified-id is required if I try to compile: #ifndef JM_FFCP_UNINITIALIZED_H #define JM_FFCP_UNINITIALIZED_H #include <boost/mpl/list.hpp> //#include <boost/statechart/custom_reaction.hpp> #include <boost/statechart/simple_state.hpp> #include <boost/statechart/transition.hpp> #include <jm/ffcp/events.h> #include <jm/ffcp/proto.h> namespace jm { namespace ffcp { namespace mpl = boost::mpl; namespace sc = boost::statechart; template< typename SocketDeviceT > struct initialized; template< typename SocketDeviceT > struct uninitialized : public sc::simple_state< uninitialized< SocketDeviceT >, proto< SocketDeviceT > > { typedef mpl::list< // sc::custom_reaction< ev_init > sc::transition< ev_init, initialized< SocketDeviceT > > > reactions; uninitialized() { uninitialized< SocketDeviceT >::custom_static_type_ptr("uninitialized"); } // sc::result react( ev_init const& ev) // { return this->template transit< initialized< SocketDeviceT > >(); } }; } } #endif // JM_FFCP_UNINITIALIZED_H Any hints? regards, Oliver

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[Threads] Conditions and avoiding lengthy mutex locks (background loading for a game)
by Peter Mackay 11 Mar '07

11 Mar '07

Hello, I'm trying to use the Boost Threads library to help me implement a background loading system for a game I'm writing. I want to enqueue load requests while the main game thread is running, and have a separate thread load the data and pass back the appropriate objects. Currently when I enqueue a new request, I notify a 'something to do' condition, which my loading thread waits on. The trouble is, when I notify it, the loader could be loading in the background, and has a lock on the mutex connected with the condition. Would anyone be able to offer me any advice on how to solve this? Many thanks, Peter P.S. Please find attached my current implementation. begin 666 loader.cpp M(VEN8VQU9&4@(FQO861E<BYH<' B#0H-"B-I;F-L=61E(#QB;V]S="]B:6YD M+FAP<#X-"@T*;&]A9&5R.CIL;V%D97(H*0T*.B!T:')E861?<VAO=6QD7V5X M:70H9F%L<V4I#0I[#0H)=&AR96%D+G)E<V5T*&YE=R!B;V]S=#HZ=&AR96%D M*&)O;W-T.CIB:6YD*"9L;V%D97(Z.G1H<F5A9%]P<F]C+"!T:&ES*2DI.PT* M?0T*#0IL;V%D97(Z.GYL;V%D97(H*0T*>PT*"2\O(%-I9VYA;"!T:&4@=&AR M96%D('1O(&5X:70N#0H)>PT*"0EB;V]S=#HZ;75T97(a)Z.G-C;W!E9%]L;V-K M(&QO8VLH;75T97(a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` ` end begin 666 loader.hpp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`` ` end

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[fusion2/phoenix2] polymorphic function objects return type
by Chris Weed 05 Mar '07

05 Mar '07

Hi, I have been looking at fusion2 and phoenix2, and I noticed fusion2 suggests using "result" as polymorphic function objects return type, but the phoenix2 documentation suggests "apply" in the examples. Are these two different things, will they be merged, or am I missing something? Thanks, Chris

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[Iterator, MSV8] iterator_adaptor fails with undefined class
by Kris Braun 04 Mar '07

04 Mar '07

Hi there, I'm using Boost 1.33.1. The following code compiles with MSVC7.1, but not with MSVC8: class Path { private: typedef std::vector< Path > PathList; public: class iterator : public boost::iterator_adaptor< iterator, PathList::const_iterator > { ... } MSVC8 gives this error: boost/type_traits/is_pod.hpp(34) : error C2139: 'fledge::Path' : an undefined class is not allowed as an argument to compiler intrinsic type trait '__is_pod' Any recommendations on a solution? Thanks, Kris --------------------------------------------------------------------- This transmission (including any attachments) may contain confidential information, privileged material (including material protected by the solicitor-client or other applicable privileges), or constitute non-public information. Any use of this information by anyone other than the intended recipient is prohibited. If you have received this transmission in error, please immediately reply to the sender and delete this information from your system. Use, dissemination, distribution, or reproduction of this transmission by unintended recipients is not authorized and may be unlawful.

2 1

[BGL] - filesystem graph
by Shams 04 Mar '07

04 Mar '07

Hi, I would like to know how to "best" represent a filesystem using BGL. In this case the filesystem I want to describe is the unix/linux filesystem and its various paths from the root node "/". My questions: 1. What kind of graph is this filesystem and what is best to use in BGL to describe this? 2. How can I also best describe symbolic links (symlinks) and what kind of graph would this be, does this graph defer from the above? 3. How can I describe the metadata of a file (including symlinks) using BGL eg. given a path /usr/bin/ls I also want to stores its creation date, acl etc in BGL, how can I best describe this, is there where properties come in handy? 4. Are there any examples on this anywhere and/or does the BGL book describe any examples on this? Thanks Shams

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(no subject)
by gzahl＠arcor.de 01 Mar '07

01 Mar '07

Hi, > Hello Manuel, >> Hi, >> >> Im defining a class with a multi_index_container as base. >> When i construct a instance of this class, and the >> multi_index_container is called, the program crashes. It even >> crashes, when i dont use it as a base class. > [...] >> This compiles just fine, but if i run the code i get the >> following backtrace after a Sigmentation Abort. It happens, >> when the queue::queue() is called. Someone a idee whats it >> about? Im new to boost::multi_index, so maybe i misunderstud >> something? Thank you > > Well, what you're doing is AFAICS correct, so you shouldn't > be getting this crash. You haven't provided a complete > test program showing producing the crash, so I wrote one > myself after what you've shown and tried it locally, no > problems here. Could you please try the attached jung.cpp > file? Does it crash also? If it doesn't then there's more > to your program than you have described, maybe you can > send compilable program showing the issue. If jung.cpp > crashes, then could you please provide the following info? The Testprogramm jung.cpp does not crash on my machines (im testing on a ubuntu 6.10 and a debian 3.1 system, both working with g++ 4.0.2) I will try to get a example which reproduces my error, but in the meantime i was thinking about the libc stuff. Maybe this is the real problem thing? i changed to 4.0.2 from a 3.x version just some weeks ago, so maybe here is the problem, because some lib im using is not compiled with 4.0.2? is there a way i can get the compiler version a library was compiled with? > > 1. What system are you running this on? > 2. The stacktrace mentions a failed assertion in libc.so. Can > you see the source code that's causing the assertion? Maybe > it sheds some light. Im not sure about, where to see this sourcecode? scoped_lock(lightweight_mutex & m): m_(m.m_) { pthread_mutex_lock(&m_); } these are the lines alst mentioned in the backtrace "/usr/local/include/boost/detail/lwm_pthreads.hpp:72" from #5. But this is not what you meant, right? > 3. Can you try the attached lock.cpp file? Crash/no crash? > I didnt tried, because example worked fine. > Looking forward to your response, Thanks for help so far. I hope we can fix it soon. Ill go on, cut some working code out, which reproduces the error. > Joaquín M López Muñoz > Telefónica, Investigación y Desarrollo Manuel Jung Viel oder wenig? Schnell oder langsam? Unbegrenzt surfen + telefonieren ohne Zeit- und Volumenbegrenzung? DAS TOP ANGEBOT JETZT bei Arcor: günstig und schnell mit DSL - das All-Inclusive-Paket für clevere Doppel-Sparer, nur 44,85 inkl. DSL- und ISDN-Grundgebühr! http://www.arcor.de/rd/emf-dsl-2

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[signals] dropping ThreadingModel template parameter
by Frank Mori Hess 01 Mar '07

01 Mar '07

It seems that now that we drop locks before running slots, we can get by with using boost/detail/lightweight_mutex.hpp for our mutex. Since it is header-only, and apparently compiles to a null mutex if the compiler is in single-threaded mode, I don't see much need for a ThreadingModel template parameter on the signal class any more. I'm dropping it from thread_safe_signals. -- Frank

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boost::variant question
by Digvijoy Chatterjee 01 Mar '07

01 Mar '07

Hi, i have a boost::variant holding some C++ types which have to be inserted into the database : boost::variant<int, std::string, double > dbColumnValueVar; before i insert the value_type into the database I need to call a processing function which is overloaded for every datatype used in the variant ie. each of these functions are defined process ( int ); process ( std::string ); process ( double); template <class T> process(T); ..... what i do not understand is how do i use apply_visitor or some other tactic to automatically dispatch the call to the right process function as in : boost::variant<int, std::string, double > dbColumnVar; dbColumnVar = "hello world"; process ( dbColumnVar ); // should call process std::string ....but is always calling the generic template version ?? dbColumnVar = 1.3434; process ( dbColumnVar ); //again calls generic template not specialization cout << dbColumnVar is somehow able to get the correct overloaded << operator for the hidden datatype irrespective of datatype ?? Any help will be appreciated Thanks Digz

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[the Boost Graph library] no matching function : vertices(const Graph& g)
by Gerd Menche 01 Mar '07

01 Mar '07

Dear Boost users, I have come across this strange problem: After designing an interface to a library dealing with molecules (OpenBabel). I get the following compiler error: /usr/include/boost/graph/breadth_first_search.hpp: In function void boost::breadth_first_search(const VertexListGraph&, typename boost::graph_traits<G>::vertex_descriptor, Buffer&, BFSVisitor, ColorMap) [with VertexListGraph = OpenBabel::OBMol, Buffer = boost::queue<OpenBabel::OBAtom*, std::deque<OpenBabel::OBAtom*, std::allocator<OpenBabel::OBAtom*> > >, BFSVisitor = boost::VerboseBFSVisitor, ColorMap = std::vector<boost::default_color_type, std::allocator<boost::default_color_type> >]: bfs_example.cpp:73: instantiated from here /usr/include/boost/graph/breadth_first_search.hpp:96: error: no matching function for call to vertices(const OpenBabel::OBMol&) Easy enough you say -- go ahead and write that function. But it is allready in place. After modiying breath_first_search.hpp on line 96 from ... vertices(g) ... to ... gvertices(g) ... and changing the name of my vertices() function to gvertices(). It works. Is there a different vertices() function defined anywhere, that gets in the way? ____________________________________________________________________________________ Looking for earth-friendly autos? Browse Top Cars by "Green Rating" at Yahoo! Autos' Green Center. http://autos.yahoo.com/green_center/

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boost 1.33.1 + qt 3.3.7 free on linux
by misiu 01 Mar '07

01 Mar '07

Hello, I'm developing standard c++ application with boost libs: any, thread, file_system, lambda, regex and everything is fine. Then I'm adding Qt for GUI and on MS Windows still fine but on Linux I got very strange problem: compilation and linking without problems (even no warnings) but just after start program hangs (even not showing GUI window) but not crushes (no core dumped). Without boost dependent parts Qt program works fine and boost parts without Qt work fine as well. What do you thing could make such a problem? What kind of checks can I do? If it is important I compiled Qt and boost by myself. I have to say I'm not so experienced with developing application on Linux, everything I'm preparing on Windows and from time to time I'm checking whether it works on Linux. Regards, Bartek

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[type_traits] is_function
by Cromwell Enage 28 Feb '07

28 Feb '07

Assuming a compiler supports is_function, will this metafunction check for the presence of member functions in a class? For example: struct Foo { void bar(); }; struct Baz { }; Given the right template argument, will is_function detect the bar() function in Foo but return false_ for Baz? If so, what is the right template argument? If not, are there any known workarounds? Cromwell D. Enage ____________________________________________________________________________________ Finding fabulous fares is fun. Let Yahoo! FareChase search your favorite travel sites to find flight and hotel bargains. http://farechase.yahoo.com/promo-generic-14795097

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