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Re: [Boost-users] shared_ptr conundrum
by Timothy Ritchey 10 Aug '05

10 Aug '05

I need to append my comments with a very import observation I just made regarding the shared_ptr issue I am having. I just copied over the binary created on my SMP machine to my UP machine, and it is showing the same problem with releasing the underlying shared pointer resource. I had been compiling the full code on both machines (including the boost threading library dll), and comparing those results, and not actually comparing the results of the same binary. The two machines are: Dell Precision 450 Workstation Dual 2.4Ghz Xeon Processors Windows XP SP2 Visual Studio 2003 Intel 8.1.??? Home Build Single AMD Athlon-64 3200+ Windows XP SP2 Visual Studio 2003 Intel 8.1.025 I just realized I don't know the exact rev of Intel I have on my machine at work, but will check it in the morning. I know it is at least 8.1.019. I seem to be looking at a problem with either SMP vs. UP builds or minor revision changes in the Intel compiler. 8.1.025 being the known working version in this case. Also, I've gotten the same results with 1.32 and 1.33 RC2. Also, thanks for a great library. We have been using it pretty extensively throughout our app; including threading, shared_ptr, spirit, date_time, bind, filesystem and multi_index (there may even be more that I can't think of right now). boost has been great fun to work with. Cheers, tim

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determinant of Matrices
by Vivid Yang 10 Aug '05

10 Aug '05

Hi, I browsed the document of ublas for a long time and did not find a convenient way to compute the determinant of a matrix. Isn't it a basic function of matrix or did I miss something? And are there functions to compute the singular values/vectors of a matrix? How about the inverse of a square full-rank matrix? btw. what is new in the new boost library version 1.33? Vivid

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hash function for edge_descriptor
by Wolfram Koska 09 Aug '05

09 Aug '05

Hello there, I was trying to create hash_maps with vertex_descriptors and edge_descriptors. The first one was easy with vertex_descriptors being just void*'s, and there is even an example in the boost detail namespace (although it's not activated using gcc): template <> struct hash< void* > { std::size_t operator()(void* v) const { return (std::size_t)v; } } But the edge_descriptors give me some serious headache. How could I create a hash function for them? Is using the source and target a good idea in graphs where there could easily be more than one edge between two vertices? Or is there a great method I cannot come up with? I hope that somebody can help me out here :) Thanks, Wolfram Koska

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string algo problem
by Giampiero Gabbiani 09 Aug '05

09 Aug '05

hi to all, I'm trying to implementing a string class as a std::list of elements that can be common char, wchar_t or something else (as utf-16 chars, for example). In order to obtain this, I've defined a collection as a template class, and used with different value_type(s). When I try to use the collection with char or wchar_t, the boost algo to_upper works fine but, when I use the collection template with a UTF16::Char (a class that implements the UTF-16 encoding) I obtain the following exception: Exception catch:St8bad_cast The following code is the definition of the Char class and an example of its use with the standard list and the boost algo: namespace UTF16 { class Char { public: Char(); Char(const char c); // UTF-16 encoding constructor Char(wchar_t v); bool operator == (const Char& c) const; bool operator != (const Char& c) const; operator wchar_t () const; Char(const Char& chr); Char(Char& chr); ~Char(); Char& operator = (const Char& chr); Char& operator = (Char& chr); private: u_int16_t* _value; size_t _size; }; } int main(int argc, char *argv[]) { try { list<UTF16::Char> l; l.push_back(UTF16::Char('a')); // THE FOLLOWING LINE PRODUCES A 'bad_cast' exception... boost::algorithm::to_upper(l); } catch(const exception& error) { cout << "Exception catch:" << error.what() << endl; } catch(...) { cerr << "Unhandled exception.\n"; } return EXIT_SUCCESS; } Is there something wrong/missing in the definition of the Char class? Or maybe the boost string algos are usable only with char and wchar_t? Thanks in advance Giampiero.

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[BGL] connected_components of filtered_graph
by Yoshi Fujiwara 09 Aug '05

09 Aug '05

With boost_1_32_0, i want to find connected components of a filtered graph. What is an appropriate second argument of algorithm, connected_components, which is applied to a filtered graph? The following obviously fails for finding components' ID for each vertex of filtered graph. // Filtered graph Graph g; // graph to be filtered typedef property_map<Graph, vertex_flag_t>::type VertexFlagMap; filter_vertex_flag<VertexFlagMap> v_filter(v_flag); typedef property_map<Graph, edge_flag_t>::type EdgeFlagMap; filter_edge_flag<EdgeFlagMap> e_filter(e_flag); typedef filtered_graph< Graph, filter_edge_flag<EdgeFlagMap>, filter_vertex_flag<VertexFlagMap> > FGraph; FGraph fg(g, e_filter, v_filter); // Connected components std::vector<int> comp(n_fg); int n_comp = connected_components(fg, make_iterator_property_map(comp.begin(), get(vertex_index,fg))); where n_fg is the number of vertices in the filtered graph. Instead make std::vector<int> comp(num_vertices(g)); and iterates over vertices in the filtered graph to see assigned components' ID, it's fine, but then i need to have extra space than necessary when a graph to be filtered is large but the filtered one is quite small. wondering what is appropriate for the second argument in my case. Though i tried to find an example in tutorial samples and checked the ML archive, i could not find a similar question before. i appreciate any help or "look at here". Yoshi

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how can I sign up to get just Boost Graph library messages?
by Aaron Archer 09 Aug '05

09 Aug '05

Does anyone know how I can sign up to receive just messages pertaining to the Boost Graph library? On the Boost-users mailing list membership configuration page, there is an option to filter the messages by topic categories, but it says "no topics defined" and has no obvious place to click, so I can't figure out how to use this option.

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Re: [Boost-users] [multi_index] - iterator validity?
by JOAQUIN LOPEZ MU?Z 09 Aug '05

09 Aug '05

----- Mensaje original ----- De: Stuart Dootson <stuart.dootson(a)gmail.com> Fecha: Martes, Agosto 9, 2005 2:26 pm Asunto: Re: [Boost-users] [multi_index] - iterator validity? > On 8/9/05, JOAQUIN LOPEZ MU?Z <joaquin(a)tid.es> wrote: [...] > > So, you can see stability is referred to in the reference > > section of each type of index. For instance, for ordered indices > > stability is (succintly) stated in > > > > > http://boost.org/libs/multi_index/doc/reference/ord_indices.html#ord_in > dices > > > > Does this clear things up for you? > > > > Best, > > > > Joaquín M López Muñoz > > Telefónica, Investigación y Desarrollo > > > > Thanks - that's exactly what I wanted. Just one thing - this statement > doesn't appear to be made generally for sequenced indices, just for > certain methods (that's in the 1.33 RC2 documentation). > Umm... yes you're right, I'll fix that bit when I regain access to the CVS in a couple of weeks or so. Thanks for spotting this. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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[Serialization] 1.33 RC1 unexpected header dependency?
by Richard Jennings 09 Aug '05

09 Aug '05

I'm finding an apparent dependency between some non-serialization headers and the use of BOOST_CLASS_EXPORT. If boost/optional.hpp or boost/format.hpp or boost/bind.hpp are included before BOOST_CLASS_EXPORT is used then I get the compilation error: [C++ Error] export.hpp(210): E2102 Cannot use template 'boost::type<T>' without specifying specialization parameters [C++ Error] export.hpp(210): E2293 ) expected If they are included after then everything's ok. This is BCB 5.6.4. This precludes me having optional/bind/format in a precompiled header and also means it's a bit tricky ensuring the correct inclusion order for a large project. Richard ========================================== Here's the code to demonstrate it: #pragma hdrstop #include <boost/archive/xml_oarchive.hpp> #include <boost/archive/xml_iarchive.hpp> #include <boost/serialization/serialization.hpp> #include <boost/serialization/export.hpp> #pragma link "libboost_serialization-bcb-mt-d-1_33.lib" // !! These can't be included here //#include <boost/format.hpp> //#include <boost/bind.hpp> //#include <boost/optional.hpp> class A { public: template <class ArchiveT> serialize(ArchiveT & ar, unsigned int) { }; }; BOOST_CLASS_EXPORT(A) // Including here is ok #include <boost/format.hpp> #include <boost/bind.hpp> #include <boost/optional.hpp> #pragma argsused int main(int argc, char* argv[]) { boost::optional<int> SomeValue; A InstanceOfA; return 0; }

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Re: [Boost-users] Maybe a problem with boost::object_pool?
by Labour, Matthieu (MLPRO SF) 09 Aug '05

09 Aug '05

Caleb Thank you for taking the time to answer my email. I actually did use a mutex to protect my queue. I did another test very simple to reproduce the problem. A program creates N threads that construct & destroy objects in an object pool With N = 9, it crashes on linux Following is the source code of the program & the gdb trace. Thank you for your help #include <iostream> #include <boost/thread/thread.hpp> #include <boost/pool/poolfwd.hpp> #include <boost/pool/object_pool.hpp> class Foo; static boost::object_pool<Foo>* _pool; class Foo{ public: void handle(){ _pool->destroy(this); } }; class Bar{ public: Bar(){} void operator()(){ for(;;){ Foo* foo = _pool->construct(); foo->handle(); } } }; int main(int argc, char* argv[]) { if(argc != 2){ std::cout << "Usage: nbThrd" << std::endl; return 0; } int nbThrd = atoi(argv[1]); _pool = new boost::object_pool<Foo>(1000); boost::thread_group _threads; Bar bar; for (int i=0; i<nbThrd; ++i){ _threads.create_thread(bar); } _threads.join_all(); return 0; } Reading symbols from /lib/libdl.so.2...done. Loaded symbols for /lib/libdl.so.2 Reading symbols from /lib/tls/libpthread.so.0...done. Loaded symbols for /lib/tls/libpthread.so.0 Reading symbols from /lib/tls/librt.so.1...done. Loaded symbols for /lib/tls/librt.so.1 Reading symbols from /usr/lib/libstdc++.so.5...done. Loaded symbols for /usr/lib/libstdc++.so.5 Reading symbols from /lib/tls/libm.so.6...done. Loaded symbols for /lib/tls/libm.so.6 Reading symbols from /lib/libgcc_s.so.1...done. Loaded symbols for /lib/libgcc_s.so.1 Reading symbols from /lib/tls/libc.so.6...done. Loaded symbols for /lib/tls/libc.so.6 Reading symbols from /lib/ld-linux.so.2...done. Loaded symbols for /lib/ld-linux.so.2 #0 boost::pool<boost::default_user_allocator_new_delete>::ordered_malloc_ne ed_resize (this=0x8fc94c0) at simple_segregated_storage.hpp:46 46 { return *(static_cast<void **>(ptr)); } (gdb) where #0 boost::pool<boost::default_user_allocator_new_delete>::ordered_malloc_ne ed_resize (this=0x8fc94c0) at simple_segregated_storage.hpp:46 #1 0x08049559 in boost::object_pool<Foo, boost::default_user_allocator_new_delete>::construct (this=0x8fca760) at object_pool.hpp:76 #2 0x08049492 in boost::detail::function::void_function_obj_invoker0<Bar, void>::invoke (function_obj_ptr= {obj_ptr = 0x8fc9628, const_obj_ptr = 0x8fc9628, func_ptr = 0x8fc9628, data = "("}) at custom.cpp:26 #3 0x00138ef5 in boost::function0<void, std::allocator<boost::function_base> >::operator() (this=0x40417a70) at function_template.hpp:581 #4 0x00138145 in thread_proxy (param=0xbfffc950) at /home/tjamet/dev/boost_1_32_0/libs/thread/src/thread.cpp:113 #5 0x00454dec in start_thread () from /lib/tls/libpthread.so.0 #6 0x00224a2a in clone () from /lib/tls/libc.so.6 -----Original Message----- From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Caleb Epstein Sent: Saturday, August 06, 2005 11:31 AM To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] Maybe a problem with boost::object_pool? On 8/5/05, Labour, Matthieu (MLPRO SF) <matthieu_labour(a)ml.com> wrote: > There are 2 threads. > One thread creates Objects using boost::object_pool and enqueues them into a > stl queue. Are you using a mutex to protect the push/pop operations on the queue? If not, then this is your problem. -- Caleb Epstein caleb dot epstein at gmail dot com _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users -------------------------------------------------------- If you are not an intended recipient of this e-mail, please notify the sender, delete it and do not read, act upon, print, disclose, copy, retain or redistribute it. Click here for important additional terms relating to this e-mail. http://www.ml.com/email_terms/ --------------------------------------------------------

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Re: [Boost-users] [multi_index] - iterator validity?
by JOAQUIN LOPEZ MU?Z 09 Aug '05

09 Aug '05

----- Mensaje original ----- De: Stuart Dootson <stuart.dootson(a)gmail.com> Fecha: Martes, Agosto 9, 2005 11:01 am Asunto: [Boost-users] [multi_index] - iterator validity? > Hi - I've just started using multi_index. I'm wondering - does > multi_index satisfy the same iterator validity constraints as the > standard associative containers, i.e: > > The insert members shall not affect the validity of iterators and > references to the container, and the erase members shall invalidate > only iterators and references to the erased elements. > > I *have* looked in the documentation, but haven't been able to find > anything which tells me. > This guarantee (stability) is held for all types of indices --ordered, sequenced and hashed (the last case is not so obvious, as TR1 does not require hashed containers to be stable.) There is no statement on the docs ensuring that multi_index_containers are stable because this is not a property of the container, but rather of each particular type of index: conceivably, a future index type may not guarantee stability for whatever reason, though currently this is not the case. So, you can see stability is referred to in the reference section of each type of index. For instance, for ordered indices stability is (succintly) stated in http://boost.org/libs/multi_index/doc/reference/ord_indices.html#ord_in dices Does this clear things up for you? Best, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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