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[optional] Comparing boost::optional<T> to NULL yield inconsistent results
by Martin B. 12 Apr '11

12 Apr '11

Hi. I have the following problem: One of our devs used (my_opt != NULL) to check an boost::optional for emptiness. This lead me to write the following test case: ... using namespace std; boost::optional<int> num_opt; boost::optional< std::string > obj_opt; if(obj_opt) { cout << "(3) Object: " << *obj_opt << endl; } // Compiles and does what the user intended - // BUT is this what the boost optional interface intends?? - // namely checking the optional for empty: if(obj_opt != NULL) { cout << "(4) Object: " << *obj_opt << endl; } if(num_opt) { cout << "(1) Integer: " << *num_opt << endl; } // Compiles and crashes, because the user actually // should have written if(num_opt) but, being used to pointers, // wrote the below, which compiles fine, but does not check for empty // but for equality with zero: if(num_opt != NULL) { cout << "(2) Integer: " << *num_opt << endl; } ... I find the behaviour of boost::optional<int> vs. opt<ClassType> highly un-intuitive. Wouldn't it be better if comparing an boost::optional always required to "dereference" it? I checked the headers (Boost 1.44) and sadly there doen't seem to be a preprocessor switch to disable the implicit comparison operators ... I would appreciate if other users could comment on my observations. Thanks! cheers, Martin

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[PBGL] add_edge return type
by Cosimo Calabrese 12 Apr '11

12 Apr '11

Hi to all, I'm trying to use the PBGL lib on VS2010, WinXP, with OpenMPI support; I've compiled without any problem the "dijkstra_shortest_paths.cpp" that I've found in \boost\libs\graph_parallel\example. So I've tried to add a new edge to the graph, and to assign a property value to it. The "classical" mode that I always have used in sequential BGL is: boost::graph_traits<Graph>::edge_descriptor ed; bool inserted; boost::tie( ed, inserted ) = boost::add_edge( boost::vertex( 0, g ), boost::vertex( 0, g ), g ); But the compiler scream... it seems that I can't initialize a tie object in that manner (I've reported the compiler log below). Instead if I first add an edge (with no assignment to tie object), and retrive it with boost::edge function, all works: boost::property_map<Graph, boost::edge_weight_t>::type weightMap = boost::get( boost::edge_weight, g ); boost::graph_traits<Graph>::edge_descriptor ed; bool exists; boost::add_edge( boost::vertex( 0, g ), boost::vertex( 0, g ), g ); boost::tie( ed, exists ) = boost::edge( boost::vertex( 0, g ), boost::vertex( 0, g ), g ); weightMap[ ed ] = 10; What's wrong? Thanks, Cosimo Calabrese. 1>src\main.cpp(75): error C2679: '=' binario: non è stato trovato alcun operatore che accetti un operando destro di tipo 'boost::adjacency_list<OutEdgeListS,VertexListS,DirectedS,VertexProperty,EdgeProperty>::lazy_add_edge'. È anche possibile che non vi siano conversioni accettabili. 1> with 1> [ 1> OutEdgeListS=boost::vecS, 1> VertexListS=boost::distributedS<boost::graph::distributed::mpi_process_group,boost::vecS>, 1> DirectedS=boost::undirectedS, 1> VertexProperty=vertex_prop, 1> EdgeProperty=boost::property<boost::edge_weight_t,float> 1> ] 1> D:\dev\lib\boost\boost/tuple/detail/tuple_basic.hpp(588): potrebbe essere 'boost::tuples::tuple<T0,T1,T2,T3,T4,T5,T6,T7,T8,T9> &boost::tuples::tuple<T0,T1,T2,T3,T4,T5,T6,T7,T8,T9>::operator =(const boost::tuples::tuple<T0,T1,T2,T3,T4,T5,T6,T7,T8,T9> &)' 1> with 1> [ 1> T0=boost::detail::parallel::edge_descriptor<boost::detail::edge_desc_impl<boost::directed_tag,unsigned int>> &, 1> T1=bool &, 1> T2=boost::tuples::detail::tie_traits<void>::type, 1> T3=boost::tuples::detail::tie_traits<void>::type, 1> T4=boost::tuples::detail::tie_traits<void>::type, 1> T5=boost::tuples::detail::tie_traits<void>::type, 1> T6=boost::tuples::detail::tie_traits<void>::type, 1> T7=boost::tuples::detail::tie_traits<void>::type, 1> T8=boost::tuples::detail::tie_traits<void>::type, 1> T9=boost::tuples::detail::tie_traits<void>::type 1> ] 1> durante la ricerca di corrispondenza con l'elenco di argomenti '(boost::tuples::tuple<T0,T1,T2,T3,T4,T5,T6,T7,T8,T9>, boost::adjacency_list<OutEdgeListS,VertexListS,DirectedS,VertexProperty,EdgeProperty>::lazy_add_edge)' 1> with 1> [ 1> T0=boost::detail::parallel::edge_descriptor<boost::detail::edge_desc_impl<boost::directed_tag,unsigned int>> &, 1> T1=bool &, 1> T2=boost::tuples::detail::tie_traits<void>::type, 1> T3=boost::tuples::detail::tie_traits<void>::type, 1> T4=boost::tuples::detail::tie_traits<void>::type, 1> T5=boost::tuples::detail::tie_traits<void>::type, 1> T6=boost::tuples::detail::tie_traits<void>::type, 1> T7=boost::tuples::detail::tie_traits<void>::type, 1> T8=boost::tuples::detail::tie_traits<void>::type, 1> T9=boost::tuples::detail::tie_traits<void>::type 1> ] 1> and 1> [ 1> OutEdgeListS=boost::vecS, 1> VertexListS=boost::distributedS<boost::graph::distributed::mpi_process_group,boost::vecS>, 1> DirectedS=boost::undirectedS, 1> VertexProperty=vertex_prop, 1> EdgeProperty=boost::property<boost::edge_weight_t,float> 1> ]

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How to skip a sub-directory with filesystem3::recursive_directory_iterator in case of exception?
by Tan, Tom (Shanghai) 12 Apr '11

12 Apr '11

> >Again, I tried something like below. >for (recursive_directory_iterator itr(root, ec), itr_end; itr!=itr_end; >) >{ > ... ; > itr.increment(ec); > if(ec) itr.pop(); >} > This time itr.pop() assertion fails because "pop() on >recursive_directory_iterator with level < 1" > >Anybody got some advice? Thanks. For others facing the same problem, I've reported it as a bug and created Ticket #5403(https://svn.boost.org/trac/boost/ticket/5403). A fix was also attached

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[serialization] enable_if managed serialize function
by Noah Roberts 11 Apr '11

11 Apr '11

I want to do something like so: template < typename Archive, typename T > typename boost::enable_if<some_meta_check<T>>::type serialize(Archive & ar, T & rec, unsigned int const) { ar & boost::serialization::base_object<T::type>(rec); } Unfortunately I run into trouble with ambiguous function call referring to a different <Archive,T> version of serialize declared in the serialization library. Does anyone know of a workaround for this?

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[optional] Could (& should) optional be more space efficient?
by David Blaikie 11 Apr '11

11 Apr '11

>From my initial look through boost::optional's implementation, it seems as though it's doing nothing to optimize its space usage in some trivial cases. The first one I was surprised by was optional<T&> - still uses sizeof(struct { T& t; }) + sizeof(bool) space, rather than simply using a pointer to represent both the reference and the unspecified state (using null, since a reference doesn't use that state). Is there a reason for this (perhaps I'm missing something & a reference is smaller than a pointer in certain implementations). Similarly - would it be worth considering optimizing optional<bool> (though, as per the documentation, this is perhaps a little "tricky" at best, owing to the implicit bool of optional itself) to use one byte instead of two? [long term - I'm wondering if a generic "efficient optionality" could be implemented by arbitrary types - privately exposing an extra unused state from their representation for use by optional only. Then, potentially, making versions of (boost/std)::shared_ptr/unique_ptr that would be never-null (only constructible via make_shared like machinery) & optional<shared_non_null_ptr<T>> would then be an explicit representation of the optional situation, but without any overhead - shared_non_null_ptr<T> would simply expose its null state only to optional<shared_non_null_ptr<T>>]

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Seeking to particular array element while deserializing
by rajiv82 11 Apr '11

11 Apr '11

I have a structure like: struct Header { vector foo; vector bar; }; I have created an array of above structure: Header *ptr = new Header[1000]; Now doing serialization/deserialization works fine with binary_oarchive. But, in some situation, I want to just deserialize particular element of array(say element at index 80). Is it possible using binary archive ? I have a work around of writing each element one by one & while de-serialization, ignore irrelevant data(in our case index 0-79) & then use proper data. But it is not optimum solution. I even tried xml archive with name as index & value as binary object by using make_binary_object. Doing something like: for(int i = 0 ; i<1000; i++) { stringstream ss ; ss << i; ar << make_nvp(ss.str().c_str(), make_binary_object(&ptr[i], 1)) ; } And deserializing 80th index object like: ar >> make_nvp("80", make_binary_object(&ptr[80], 1)) ; Program compiles fine, but result is inconsistent. Please suggest is there any better way to read(deserialize) just one element of an array. -- View this message in context: http://boost.2283326.n4.nabble.com/Seeking-to-particular-array-element-whil… Sent from the Boost - Users mailing list archive at Nabble.com.

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Monitoring thread liveness using multiple threads with a single asio io_service
by Krajnak, Mike (GE Healthcare) 11 Apr '11

11 Apr '11

We have a server implemented with boost::asio that uses a vector of threads with a single io_service as in the asio http server 3 sample program. We want to check on the liveness of threads by having each thread periodically call back to a thread manager so that we can confirm it is still running. To do that we have an inner loop that uses run_one() so we can call our heartbeat function after each action is completed (pseudo code): do { num_ops = io_svc.run_one(ec) heartbeat_to_thread_manager(); } while (num_ops > 0); However, asio makes no garantees on how work is dispatched to threads. In our testing work seems to go prefentially to one thread for several iterations before going to another thread with no pattern that we can find. Is there some way we can change this solution so that we can be reasonably sure each thread will be called at least once in a some period of time or some other mechanism for monitoring thread liveness? Thanks, Mike

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Re: [Boost-users] Compiling Boost with 4 byte packing...
by Brian Nantz 11 Apr '11

11 Apr '11

I finally got boost to build with visual studio 2008 and 4-byte packing. Here is what I had to do: 1. Edit the tools\build\v2\user-config.jam and add: using msvc : vc9 : "D:/Program Files/Microsoft Visual Studio 9.0/VC/bin/cl.exe" : <compileflags>-DBOOST_HAS_ABI_HEADERS <compileflags>-DBOOST_PROTO_MAX_ARITY=10 <compileflags>-DBOOST_MPL_CFG_NO_PREPROCESSED_HEADERS <compileflags>-DBOOST_MPL_LIMIT_METAFUNCTION_ARITY=10 <compileflags>-DWIN32 <compileflags>-D_DEBUG <compileflags>-D_LIB <compileflags>-D_WIN32_WINNT=0x0501 <compileflags>-D_UNICODE <compileflags>-DUNICODE <compileflags>-DBOOST_ASIO_ENABLE_BUFFER_DEBUGGING <compileflags>-Gm <compileflags>-EHsc <compileflags>-RTC1 <compileflags>-MTd <compileflags>-Zp4 <compileflags>-W4 <compileflags>-c <compileflags>-ZI <compileflags>-TP <linkflags>/MACHINE:X86 ; 2. On the bjam command line use the options: --toolset=msvc-9.0 cxxflags=-Zp4 3. Edit boost/config/user.hpp: // BOOST_ABI_PREFIX: A prefix header to include in place of whatever // boost.config would normally select, any replacement should set up // struct packing and alignment options as required. #define BOOST_ABI_PREFIX <boost/config/abi/saplib_prefix.hpp> // BOOST_ABI_SUFFIX: A suffix header to include in place of whatever // boost.config would normally select, any replacement should undo // the effects of the prefix header. #define BOOST_ABI_SUFFIX <boost/config/abi/saplib_suffix.hpp> The prefix header just contains #pragma pack(push,4) and the suffix just has #pragma pack(pop) 4. For some reason ASIO does not use the boost ABI header prefix and suffix. It has its own. Edit boost/asio/detail/push_options.hpp to use #pragma pack(push,4). The boost build now completes cleanly (with no errors or warnings) on boost 1.43. There seems to be some room for simplification or improvement here?

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[boost-users][parameter] ArgumentPack Documentation Best Practices
by Christoph Heindl 11 Apr '11

11 Apr '11

Hi, I wonder if anyone could share his best practices as far as documenting Boost.Parameter enabled constructors is concerned. I'm currently doing something along the lines of /** Construct from named parameters and use defaults where parameters are empty * * * \tparam Opts ArgumentPack of options. The following options are supported * - \a min_group_size minimum number of supporting correspondences to form a group. * - \a ntrials number of times to form basis from two randomly selected correspondences. * - \a bin_size_pos quantization size for transformed point coordinates. * - \a bin_size_orientation quantization in radians for surface orientation angles. * */ template<class Opts> group_geo_hash(const Opts &opts) { this->init( opts[Keywords::_min_group_size | 10], opts[Keywords::_bin_size_pos | LibFundament::rasFloat(10)], opts[Keywords::_orientation_rad | LibFundament::rasFloat(0.2)], opts[Keywords::_ntrials | 0]); } } which is sub-optimal, because default values for options and option types are missing. Doxygen can deduce types for regular parameters as well as default values. Ideally this should work for boost.parameters as well :) Even better, Doxygen could warn about undocumented parameters. Any thoughts? Best regards, Christoph

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Re: [Boost-users] [Boost.Thread] Multithreaded Multithreaded Server (Ian Mallett)
by Marat Abrarov 11 Apr '11

11 Apr '11

> Hi, > > Fairly new to Boost. Bear with me. > > I'm trying to write a multithreaded multithreaded server (two multithreaded > operations): ideally, there should be a single process, containing at least two threads. The first > thread handles various tasks (and can start other threads to help it as well). The other thread waits > for incoming connections, and adds a new thread for each one: http://sourceforge.net/projects/asio-samples/ Look at projects "echo_server" and "qt_echo_server". They use 2 thread pools among main (GUI) thread. One thread pool (size is 1-2 threads) executes session management loop: acceptance (with limited number of active sessions), start of accepted session, end of all sessions. Second thread pool (by default is CPU number bounded) executes sessions' loops: start of asynchronous read, start of asynchronous write, IO operation completion handling. Regards, Marat Abrarov.

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Re: [Boost-users] [MSM] problem compiling a functor-guard using a flaginside.
by Christophe Henry 11 Apr '11

11 Apr '11

>while developing I want to use functors for a guard. The state machine compiles well until I added a >function call to the FSM which has a template parameter. Then I always got the following error message >while compiling it with gcc 4.4.1. >SubtractionControllerNew.cpp: In member function ‘bool<unnamed>::player_::isCDLoaded::operator()(const EVT&, FSM&, SourceState&, TargetState&)’: >SubtractionControllerNew.cpp:175: error: expected primary-expression before ‘>’ token >SubtractionControllerNew.cpp:175: error: expected primary-expression before ‘)’ token >Does anybody know why this happens and how to circumvent it? I admit C++ is sometimes full of hard-to-get rules :( Try adding a template keyword: struct isCDLoaded { template <class EVT,class FSM,class SourceState,class TargetState> bool operator()(EVT const& ,FSM& fsm,SourceState& ,TargetState& ) { //return fsm.is_contained(); // this works well return fsm.template is_flag_active<CDLoaded>(); // Line 175 } }; HTH, Christophe

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[Fusion] Output of adapted ADT
by Tore Halvorsen 11 Apr '11

11 Apr '11

Hi, I'm trying to output a string from an adapted class, but I'm getting 1>main.cpp(33): error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'boost::fusion::extension::adt_attribute_proxy<foo,0,false>' (or there is no acceptable conversion) for the following code (boost 1_46_1, msvc2010) Is there a header I'm missing? Very similar code works for BOOST_FUSION_DEFINE_STRUCT - and using ints or doubles also work... #include <iostream> #include <string> #include <ostream> #include <boost/fusion/include/adapted.hpp> #include <boost/fusion/sequence.hpp> class foo { public: foo(std::string const& str) : s(str) { } std::string const& get_s() const { return s; } void set_s(std::string const& str) { s = str; } private: std::string s; }; BOOST_FUSION_ADAPT_ADT( foo, (std::string const&, std::string const&, obj.get_s(), obj.set_s(val)) ); int main(int argc, char* argv[]) { foo f("foo"); std::cout << boost::fusion::front(f) << std::endl; return EXIT_SUCCESS; } -- Eld på åren og sol på eng gjer mannen fegen og fjåg. [Jøtul] <demo> 2011 Tore Halvorsen || +052 0553034554

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[Boost.Thread] Multithreaded Multithreaded Server
by Ian Mallett 10 Apr '11

10 Apr '11

Hi, Fairly new to Boost. Bear with me. I'm trying to write a multithreaded multithreaded server (two multithreaded operations): ideally, there should be a single process, containing at least two threads. The first thread handles various tasks (and can start other threads to help it as well). The other thread waits for incoming connections, and adds a new thread for each one: Server process: -Thread 1 (Handle background server operations, etc.) -helper thread 1 -helper thread 2 ... -helper thread *n* -Thread 2 (Listen for incoming connections. When found, make a new connection thread to handle it) -connection thread 1 -connection thread 2 ... -connection thread *n* I began by making heavy use of the example here<http://www.boost.org/doc/libs/1_36_0/doc/html/boost_asio/example/echo/async…>. Please see my attached files for my implementation. The classes "mMindThreadServerListener" and "mMindServerHandlerClient" correspond to "server" and "session", respectively. "mMindServer" is the highest level (server process). In it, there's a thread group that contains "Thread 1" ("_thread_connection_pruner", which kills unused connections, and represents a background server operation) and "Thread 2" ("_thread_listener", which listens for incoming connections). Thread 2's need to make other threads seems to be handled by boost::asio::io_service. Unfortunately, when a connection is found, Thread 1 stops. I can only attribute this to a lock boost::asio::io_service puts, although I have no idea. Can someone explain what's going on, and possibly a better way to do this? Thanks, Ian

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BOOST and Android
by Claude 10 Apr '11

10 Apr '11

Hi! It is possible compile/use BOOST with Android (3.0?) NDK? -- View this message in context: http://boost.2283326.n4.nabble.com/BOOST-and-Android-tp3439871p3439871.html Sent from the Boost - Users mailing list archive at Nabble.com.

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Re: [Boost-users] [MSM] Use events twice
by Christophe Henry 10 Apr '11

10 Apr '11

> I'm using MSM to implement a client for a simple network application. Basically, the server sends messages and the client changes state and responds to them as appropriate. > > One of these messages is THROW. THROW gets two arguments: an identifier (0-3) and a value. My client is supposed to sum up the values for consecutive THROW events with the same identifier, and on a change of identifier, store the sum somewhere and start over for the new identifier. > > So I have three states (id0, id1, id2 - there's some special handling, which is why they're separate states) and an event Throw(id, value). The transitions for idN are: > Throw(my id, value) -> no switch, state.sum += value > Throw(other id, value) -> switch to state of other id, reprocess event, storing the sum is handled by the exit action > > In other words, I want the next state to immediately handle the event as well, because there's a value there I need to store. The question is, how do I do this? > > Here's a sequence of events and actions that could occur: > E1: [init] Throw(0, 4) -> [id0: ?] > Entry [id0: ?] -> [id0: 0] > [id0: 0] reprocess E1 -> [id0: 4] > E2: [id0: 4] Throw(0, 8) -> [id0: 12] > E3: [id0: 12] Throw(1, 7) -> [id1: ?] > Exit [id0: 12] -> save 12 > Entry [id1: ?] -> [id1: 0] > [id1: 0] reprocess E3 -> [id1: 7] Hi Sebastian, Let's see if I get it. Reprocessing is not going to be the problem, I suppose. An action reprocessing an event untouched would be: struct reprocess { template <class Fsm,class Evt,class SourceState,class TargetState> void operator()(Evt const& evt,Fsm& fsm,SourceState& ,TargetState& ) { fsm.process_event(evt); } }; MSM has a message queue by default so you have no risk of deadlocking yourself. Actually you might not even need to reprocess if you use internal actions and transition conflicts, so I suggest a different version. For every Throw event, sou create a conflict between a state internal transition (not necessary but more elegant and with more reuse, see below) and an external one, leading to another state if the id contained in Throw is not the one from the current state. If it is the one from the current state, we add the value from the event. I also added an Init state to make it simpler. Now, all I need to do is make the states template classes and write just one. I attach an example. Please tell me if that's what you're looking for. Christophe

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any_range vs. “canonical form” - what is the latter?
by John Funnell 10 Apr '11

10 Apr '11

Boost's any_range documentation says the following: "Despite the underlying any_iterator being the fastest available implementation, the performance overhead of any_range is still appreciable due to the cost of virtual function calls required to implement increment, decrement, advance, equal etc. Frequently a better design choice is to convert to a canonical form." What does the author mean by a "canonical form"? Can someone give an example? Many thanks [question originally asked at http://stackoverflow.com/questions/5601303]

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boost::mpl::plus changes type
by Peter Foelsche 10 Apr '11

10 Apr '11

It is a major annoyance that these arrithmetic operations return a different type than the input! I mean I input boost::mpl::long_ and I get a boost::mpl::integral_c Peter

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boost::mpl::abs missing
by Peter Foelsche 10 Apr '11

10 Apr '11

There is no boost::mpl::abs Peter

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[network] cpp-netlib v0.9-beta out now!
by Dean Michael Berris 09 Apr '11

09 Apr '11

Hi Everyone, Apologies for the cross-post, but I just want to announce that after a couple months delay because of some outstanding bugs and TODO items that needed to get dealt with, I am now ready to package a 0.9 release and with that in mind I've just uploaded the 0.9-beta release of cpp-netlib. When the beta period (1 week) is over and all outstanding bugs are addressed, the 0.9 release will be the basis for submission for review to the Boost C++ Library. You can get the beta from: https://github.com/cpp-netlib/cpp-netlib/downloads What's New in 0.9 (taken from the documentation): - IMPORTANT BREAKING CHANGE: By default all compile-time heavy parser implementations are now compiled to external static libraries. In order to use cpp-netlib in header-only mode, users must define the preprocessor macro BOOST_NETWORK_NO_LIB before including any cpp-netlib header. This breaks code that relied on the version 0.8.x line where the library is strictly header-only. - More consistent message API for client and server messages (request and response objects). - Refactoring of internal implementations to allow better separation of concerns and more manageable coding/documentation. - Client and Server constructors that support Boost.Parameter named parameters. - Client and Server cosntructors now take in an optional reference to a Boost.Asio io_service to use internally. - Documentation updates to reflect new APIs. This Beta has been tested mainly on Linux (GCC 4.4, 4.5) and Mac OS X (10.6.7, Xcode 3.2.x w/ GCC 4.2.1) builds against Boost trunk and Boost 1.45. Note that cpp-netlib does NOT work with Boost 1.46.1 because of some breaking changes in the Boost.Spirit customization points have caused cpp-netlib to cease to play well with it. That said, the issues have been addressed in Boost trunk and should be fixed in Boost.147. Thanks to everyone who contributed to making this Beta possible, namely Emre Turkay, Oleg Malashenko, and other users that filed issues on the Github issue tracker. Have a good day everyone and I do look forward to feedback! -- Dean Michael Berris http://about.me/deanberris

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[Interprocess] shared_ptr in a non-throwing mode
by Pietro Versari 09 Apr '11

09 Apr '11

Hi Ion (and everyone else), I'm a newbye and I have only one simple question: how can I construct a shared_ptr in a non-throwing mode? This example throw if there is enough space for MyType but isn't enough for my_shared_ptr: typedef managed_shared_ptr<MyType,managed_shared_memory>::type my_shared_ptr; my_shared_ptr sh_ptr = make_managed_shared_ptr( segment.construct<MyType>("object to share", std::nothrow)(), segment); Thanks, Pietro Versari

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enable_if and multiple partial specializations
by Gennadiy Rozental 09 Apr '11

09 Apr '11

Hi, It's late and I might be missing something, but I can't figure out how can I use enable_if to disambiguate 2 partial specializations where one is subcase of another one: #include <boost/utility/enable_if.hpp> #include <boost/type_traits/is_enum.hpp> #include <boost/type_traits/is_scalar.hpp> #include <iostream> template<typename T, typename Enabler=void> struct M { static void foo() { std::cout << "generic" << std::endl; } }; template<typename T> struct M<T, typename boost::enable_if<boost::is_scalar<T> >::type> { static void foo() { std::cout << "scalar" << std::endl; } }; template<typename T> struct M<T,typename boost::enable_if<boost::is_enum<T> >::type> { static void foo() { std::cout << "enum" << std::endl; } }; struct S {}; enum FOO { FOO1, FOO2 }; int main() { M<S>::foo(); M<int>::foo(); M<FOO>::foo(); } --------------- M<FOO>::foo() fails to compile due to ambiguity. Any pointers? Or How to get what I want? Gennadiy

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[multi_array] Is there interest for an [index_list] library?
by Pierre-Andre Noel 08 Apr '11

08 Apr '11

Dear all, I would like to gauge the interest of the community in a library that can serve 1) as a complement to Boost.MultiArray and 2) as an alternative to Boost.MultiArray. For the first type of use, an example of the candidate library's capabilities is that it makes available a special iterator "it" that allows to browse all the elements of a MultiArray "m". This special iterator has an it.indices() members that returns a "list" Collection of indices (i.e. an IndexList) such that "m(list)" and "*it" are the same elements. This can be useful for functions whose effect on an element of "m" depends on where this element is situated in "m". The second way to use the candidate library is as an alternative to Boost.MultiArray of dynamically chosen (execution time) dimensionality. Moreover, the elements do not necessarily need to be arranged in a multi-dimensional "box", as is the case in a MultiArray. For example, a "simplex" organization of the elements is already implemented. If you are interested to know more, I strongly suggest you to take a look at the example file in sandbox/index_list/libs/index_list/examples.cpp . The library itself is in sandbox/index_list/boost and a readme file (with some details concerning concepts and "priorities") is in sandbox/index_list/libs/README . An automatically generated (Doxygen) documentation is located in sandbox/index_list/libs/index_list/doc/index.html . Sadly, there is no "real" documentation for now. Many thanks for your time. Sincerely, Pierre-André Noël

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[BGL] Accelerating property value-retrieval
by Cedric Laczny 08 Apr '11

08 Apr '11

Hi, I would like to know if there is a way to accelerate the retrieval of properties of an edge or a vertex? Actually, I define a new vertex-property (vertex_properties) and this again uses a "struct VertexProperties { ... }" to specify the details of the properties. However, when I want to get the properties of say vertex v, I need to first get the properties-map from the graph and then get the property for v. This obviously suffers from the lookup in the property_map and I would like to know if there is a way to accelerate this? In particular, when using vecS as the vertex_container because the vertices could generally be used as indices... I would find this very convenient, especially in combination with filtered_graph when filtering only on vertices that have certain properties (e.g. a category) and one only wants to see those that have a specific character (e.g. color). Best, Cedric

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[ filesystem ] 1.45 broken on gcc 4.5 on AIX 5.3
by Avi Bahra 08 Apr '11

08 Apr '11

OK I realise AIX/gcc is not really a supported platform? But in boost 1.45 the file system causes a crash. My understanding was that at 1.45 the file system v2 was the default ? However looking at the stack trace it appears that at start up file system v3 make use of a static object to set the locale(), see file path.cpp namespace boost { namespace filesystem3 { const path::codecvt_type *& path::wchar_t_codecvt_facet() { static const std::codecvt<wchar_t, char, std::mbstate_t> * facet( &std::use_facet<std::codecvt<wchar_t, char, std::mbstate_t> > (path_locale())); return facet; } ..... path_locale() ends up calling default_locale(), which call's std::locale("") In std::locale() for some reason the locale can not be created and an exception is thrown. This exception has no chance of being caught since it called before main(). See the totalview trace back below: The work around appears to be to set the environment variable LANG to an empty string. Have not tested this on boost 1.46, but I suspect the same problem. Best regards, Avi ================================================================ .pthread_kill, FP=2ff20380 ._p_raise, FP=2ff203f0 .raise, FP=2ff20440 .abort, FP=2ff20490 uw_init_context_1, FP=2ff204f0 _Unwind_RaiseException, FP=2ff20a10 .__cxa_throw, FP=2ff21600 ._ZSt21__throw_runtime_errorPKc, FP=2ff21640 ._ZNSt6locale5facet18_S_create_c_localeERPiPKcS1_, FP=2ff216a0 ._ZNSt6locale5_ImplC2EPKcm, FP=2ff216e0 ._ZNSt6localeC2EPKc, FP=2ff21770 _ZN60_GLOBAL__N_libs_filesystem_v3_src_path.cpp_00000000_60BE389714default_localeEv, FP=2ff21800 _ZN60_GLOBAL__N_libs_filesystem_v3_src_path.cpp_00000000_60BE389711path_localeEv, FP=2ff21840 _ZN5boost11filesystem34path21wchar_t_codecvt_facetEv, FP=2ff21890 _ZN5boost11filesystem34path7codecvtEv, FP=2ff218e0 ..._cEERKT_PNS_9enable_ifINS0_11path_traits11is_pathableINS_5decayIS4_E4typeEEEvE4typeE, FP=2ff21920 _Z41__static_initialization_and_destruction_0ii, FP=2ff21980 _GLOBAL__I_65535_0__ZN5boost11filesystem34pathdVERKS1_, FP=2ff219c0 ._GLOBAL__FI_coretest, FP=2ff21a00 .__modinit, FP=200cde4c **** Frame below previous frame ********** .__modinit, FP=2ff21c20 .__start, FP=2ff21cb0

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Building Boost using OS X 10.4 deployment target with 10.6 base SDK
by Brad Anderson 08 Apr '11

08 Apr '11

I upgraded to XCode 4 recently which only includes/supports the 10.6 SDK. While trying to build Boost 1.46.1 with a deployment target (macosx-version-min) of 10.4 I get a bjam error about 10.4 not being a valid option for macosx-version-min (the only valid option listed is 10.6). Perhaps I'm confused about something but I was under the impression that you could build using a newer base SDK than your target version. With XCode 3 I just used 10.4 as the base SDK and deployment target as that SDK is included and had no issues. I built wxWidgets fine using a 10.4 deployment target and 10.6 base SDK. Does anyone have experience with doing this in Boost? Regards, Brad Anderson

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compiler crash in signals2?
by Noah Roberts 08 Apr '11

08 Apr '11

I get this error: 1>------ Build started: Project: barf, Configuration: Debug Win32 ------ 1> main.cpp 1> using native typeof 1>d:\boost-1.42.0-msvc10\boost-1.42-msvc10\include\boost\smart_ptr\shared_ptr.hpp(231): fatal error C1001: An internal error has occurred in the compiler. 1> (compiler file 'msc1.cpp', line 1420) 1> To work around this problem, try simplifying or changing the program near the locations listed above. 1> Please choose the Technical Support command on the Visual C++ 1> Help menu, or open the Technical Support help file for more information 1> d:\boost-1.42.0-msvc10\boost-1.42-msvc10\include\boost\signals2\detail\signal_template.hpp(699) : while compiling class template member function 'boost::shared_ptr<T> boost::signals2::signal1<R,T1,Combiner,Group,GroupCompare,SlotFunction,ExtendedSlotFunction,Mutex>::lock_pimpl(void) const' 1> with 1> [ 1> T=void, 1> R=void, 1> T1=const esi::units::unit_settings &, 1> Combiner=boost::signals2::optional_last_value<void>, 1> Group=int, 1> GroupCompare=std::less<int>, 1> SlotFunction=boost::function<void (const esi::units::unit_settings &)>, 1> ExtendedSlotFunction=boost::function<void (const boost::signals2::connection &,const esi::units::unit_settings &)>, 1> Mutex=boost::signals2::mutex 1> ] 1> d:\boost-1.42.0-msvc10\boost-1.42-msvc10\include\boost\signals2\preprocessed_signal.hpp(42) : see reference to class template instantiation 'boost::signals2::signal1<R,T1,Combiner,Group,GroupCompare,SlotFunction,ExtendedSlotFunction,Mutex>' being compiled 1> with 1> [ 1> R=void, 1> T1=const esi::units::unit_settings &, 1> Combiner=boost::signals2::optional_last_value<void>, 1> Group=int, 1> GroupCompare=std::less<int>, 1> SlotFunction=boost::function<void (const esi::units::unit_settings &)>, 1> ExtendedSlotFunction=boost::function<void (const boost::signals2::connection &,const esi::units::unit_settings &)>, 1> Mutex=boost::signals2::mutex 1> ] 1> d:\dev_workspace\pfp_qt\experiment\build\include\esi\units\unit_settings.hpp(284) : see reference to class template instantiation 'boost::signals2::signal<Signature>' being compiled 1> with 1> [ 1> Signature=void (const esi::units::unit_settings &) 1> ] ========== Build: 0 succeeded, 1 failed, 1 up-to-date, 0 skipped ========== The version of boost I'm using is 1.42. I'm wondering if this problem has turned up before and if its got a fix. I'm not entirely convinced that it actually has anything to do with what it's claiming the cause is. I'm working on a library that does a lot of recursive template instantiations and behaves in a similar manner to fusion in many respects. Previous directions I went with this library already cause compiler crashes on a regular basis (2010 apparently doesn't do well with recursive calls to auto->decltype template functions). My library code could certainly use some cleaning up, but it's all legal C++ as far as I can tell. Also, this crash only happens when I try to use in conjunction with said library and only happens when the construct containing the signal is in a particular header file. If I move it to another and go ahead and include that one...everything works just fine. Obviously, this is VS's fault, not mine or boost's...but if there's a workaround/fix that's been made for this problem (assuming it is related to signals2 and comes up for other people) I'd like to be aware of it.

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BoostCon 2011: Registration deadline is Wednesday
by Dave Abrahams 08 Apr '11

08 Apr '11

The premier annual US C++ event, BoostCon, runs May 15-20, 2011 in beautiful Aspen, Colorado! See http://boostcon.boost.org for details. Hans Boehm, the father of C++ garbage collection and the C++0x threading model, headlines the fifth annual Boost Conference, with his keynote, "Threads and Shared Variables in C++0x." Other sessions about which which I'm personally excited: * Christopher Kohlhoff, the author of ASIO, is coming all the way from the "land down under" to present his library, slated for TR2. Also IPv6, and more! * Bartosz Milewski is going to talk about the relationship between C++ template metaprogramming and Haskell * Matt Calabrese presents his library implementation of the postponed C++0x concepts features Further topics include Unicode, lockfree programming, Boost.Units, compile-time graphs, database mapping, high-performance numerics, and... too many other good things to list. I'll be running a daily infrastructure workshop where we'll develop the frameworks for documentation, web services, build, test, packaging and distribution of C++ components, including ryppl. As usual, the best things about BoostCon are the people and the work that gets done between sessions. The pictures at http://boostcon.boost.org/photos/ give a pretty good sense of it, but there's truly no substitute for being there. If you haven't registered yet, fix that :-) at http://boostcon.boost.org/registration/. Your chance to save $100 expires on Wednesday. See you there! -- Dave Abrahams BoostPro Computing http://www.boostpro.com

1 1

Returning a ptr_vector of an abstract data type
by Jim Hodapp 08 Apr '11

08 Apr '11

I am using a ptr_vector<MyAbstractType> in a class called Container to store pointers to derived types inherited from MyAbstractType. In my Container class, I want to have a member function which returns the ptr_vector<MyAbstractType>. First, am I better off modelling this "getter" as an iterator over this ptr_vector or is it proper to return the ptr_vector itself? Right now, when trying to return the ptr_vector itself (a copy of it) I am getting an error: "/usr/include/boost/ptr_container/clone_allocator.hpp:34: error: cannot allocate an object of abstract type 'MyAbstractType' The function prototype for the getter is: ptr_vector<MyAbstractType> GetDestinations() const Is ptr_vector trying to make a copy of each MyAbstractType contained instead of copying the pointer value itself? This would indicate that I need a get() type method for ptr_vector like what a scoped_ptr has. Any recommendations on how to design this situation? Thanks, Jim

3 2

mutable_buffer_1 Inquiry
by Carla Strembicke 08 Apr '11

08 Apr '11

Hi, I am using the asio::mutable_buffer_1. All I want to do is copy external data from buffer to the Buffer that the mutable_buffer_1 is assigned. I have been reading the documentation provided but am unable to make heads or tails as to how to get this simple operation done. Is this possible. Do I have to sue the stream buffer class and if so how? Thanks CONFIDENTIAL INFORMATION NOTICE: The information contained in this e-mail is privileged, confidential and intended solely for the use of the addressee named above. If the reader of this e-mail is not the intended recipient, you are hereby notified that any dissemination, distribution or copying of this e-mail is strictly prohibited. If you received this in error, please contact the sender and destroy all copies of this e-mail. Thank you.

2 1

boost::multi_index
by ppatel＠archelongroup.com 08 Apr '11

08 Apr '11

Hello, I have a question regarding creating composite key/specifying length for arrays while using multi_index container based on following structure. struct TestStruct { char firstKey[50]; char secondKeyPart[3]; uint32_t thirdKeyPart; ......Some other information.... }; Do I really read to specify this lengths for character arrays? If yes, how do I do that while specifying key parts as below? typedef multi_index_container < TestStruct, indexed_by< //non-unique as some subscribers might have more than one number hashed_unique< composite_key< TestStruct, member<TestStruct, char*, &TestStruct::firstKeyPart>, member<TestStruct, char*, &TestStruct::secondKeyPart>, member<TestStruct, uint32_t, &TestStruct::thirdKeyPart>, > > > > TS; Thanks

5 7

[MSM] Use events twice
by Sebastian Redl 08 Apr '11

08 Apr '11

Hi, I'm using MSM to implement a client for a simple network application. Basically, the server sends messages and the client changes state and responds to them as appropriate. One of these messages is THROW. THROW gets two arguments: an identifier (0-3) and a value. My client is supposed to sum up the values for consecutive THROW events with the same identifier, and on a change of identifier, store the sum somewhere and start over for the new identifier. So I have three states (id0, id1, id2 - there's some special handling, which is why they're separate states) and an event Throw(id, value). The transitions for idN are: Throw(my id, value) -> no switch, state.sum += value Throw(other id, value) -> switch to state of other id, reprocess event, storing the sum is handled by the exit action In other words, I want the next state to immediately handle the event as well, because there's a value there I need to store. The question is, how do I do this? Here's a sequence of events and actions that could occur: E1: [init] Throw(0, 4) -> [id0: ?] Entry [id0: ?] -> [id0: 0] [id0: 0] reprocess E1 -> [id0: 4] E2: [id0: 4] Throw(0, 8) -> [id0: 12] E3: [id0: 12] Throw(1, 7) -> [id1: ?] Exit [id0: 12] -> save 12 Entry [id1: ?] -> [id1: 0] [id1: 0] reprocess E3 -> [id1: 7] I hope I was clear enough. Sebastian

1 0

[BGL] Writing an edge_iterator for add_edges in CSR graph
by Johan Oudinet 08 Apr '11

08 Apr '11

Hi, I'm trying to write an edge_iterator in order to load a CSR graph from a GraphViz by using the add_edges method. So far, I successfully write a edge_iterator so you can iterate on it and dereference it to get either a pair of vertex_descriptor or a edge label. However, if it try to use this iterator as arguments for the method add_edges of CSR graph, I got cryptic errors and I don't know how to solve them :-/ You can find the code that produce these errors here: http://tinyurl.com/csr-add-edges-error I will appreciate any help to understand what is going wrong or to write an edge_iterator that actually works with add_edges. Thanks. Regards, P.S.: I use Boost graph library 1.42 installed from Ubuntu 10.10 repositories. -- Johan () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments

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[MSM] problem compiling a functor-guard using a flag inside.
by Steckmann, Sven 08 Apr '11

08 Apr '11

Dear list, while developing I want to use functors for a guard. The state machine compiles well until I added a function call to the FSM which has a template parameter. Then I always got the following error message while compiling it with gcc 4.4.1. SubtractionControllerNew.cpp: In member function 'bool<unnamed>::player_::isCDLoaded::operator()(const EVT&, FSM&, SourceState&, TargetState&)': SubtractionControllerNew.cpp:175: error: expected primary-expression before '>' token SubtractionControllerNew.cpp:175: error: expected primary-expression before ')' token Does anybody know why this happens and how to circumvent it? Kind regards, Sven ---- Example from flags. I have modified the CDLoaded example to present the bug with the following lines: struct isCDLoaded { template <class EVT,class FSM,class SourceState,class TargetState> bool operator()(EVT const& ,FSM& fsm,SourceState& ,TargetState& ) { //return fsm.is_contained(); // this works well return fsm.is_flag_active<CDLoaded>(); // Line 175 } }; Row < Stopped , open_close , Open , none , isCDLoaded >, // Copyright 2010 Christophe Henry // henry UNDERSCORE christophe AT hotmail DOT com // This is an extended version of the state machine available in the boost::mpl library // Distributed under the same license as the original. // Copyright for the original version: // Copyright 2005 David Abrahams and Aleksey Gurtovoy. Distributed // under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at // http://www.boost.org/LICENSE_1_0.txt) #include <iostream> // back-end #include <boost/msm/back/state_machine.hpp> //front-end #include <boost/msm/front/state_machine_def.hpp> #include <boost/msm/front/functor_row.hpp> #include <boost/msm/front/euml/common.hpp> namespace msm = boost::msm; namespace mpl = boost::mpl; using namespace msm::front; namespace // Concrete FSM implementation { // events struct play {}; struct end_pause {}; struct stop {}; struct pause {}; struct open_close {}; struct NextSong {}; struct PreviousSong {}; // Flags. Allow information about a property of the current state struct PlayingPaused{}; struct CDLoaded {}; struct FirstSongPlaying {}; // A "complicated" event type that carries some data. struct cd_detected { cd_detected(std::string name) : name(name) {} std::string name; }; // front-end: define the FSM structure struct player_ : public msm::front::state_machine_def<player_> { // The list of FSM states struct Empty : public msm::front::state<> { // every (optional) entry/exit methods get the event passed. template <class Event,class FSM> void on_entry(Event const&,FSM& ) {std::cout << "entering: Empty" << std::endl;} template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "leaving: Empty" << std::endl;} }; struct Open : public msm::front::state<> { typedef mpl::vector1<CDLoaded> flag_list; template <class Event,class FSM> void on_entry(Event const&,FSM& ) {std::cout << "entering: Open" << std::endl;} template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "leaving: Open" << std::endl;} }; struct Stopped : public msm::front::state<> { // when stopped, the CD is loaded typedef mpl::vector1<CDLoaded> flag_list; template <class Event,class FSM> void on_entry(Event const&,FSM& ) {std::cout << "entering: Stopped" << std::endl;} template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "leaving: Stopped" << std::endl;} }; // the player state machine contains a state which is himself a state machine // as you see, no need to declare it anywhere so Playing can be developed separately // by another team in another module. For simplicity I just declare it inside player struct Playing_ : public msm::front::state_machine_def<Playing_> { // when playing, the CD is loaded and we are in either pause or playing (duh) typedef mpl::vector2<PlayingPaused,CDLoaded> flag_list; template <class Event,class FSM> void on_entry(Event const&,FSM& ) {std::cout << "entering: Playing" << std::endl;} template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "leaving: Playing" << std::endl;} // The list of FSM states struct Song1 : public msm::front::state<> { typedef mpl::vector1<FirstSongPlaying> flag_list; template <class Event,class FSM> void on_entry(Event const&,FSM& ) {std::cout << "starting: First song" << std::endl;} template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "finishing: First Song" << std::endl;} }; struct Song2 : public msm::front::state<> { template <class Event,class FSM> void on_entry(Event const&,FSM& ) {std::cout << "starting: Second song" << std::endl;} template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "finishing: Second Song" << std::endl;} }; struct Song3 : public msm::front::state<> { template <class Event,class FSM> void on_entry(Event const&,FSM& ) {std::cout << "starting: Third song" << std::endl;} template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "finishing: Third Song" << std::endl;} }; // the initial state. Must be defined typedef Song1 initial_state; // transition actions void start_next_song(NextSong const&) { std::cout << "Playing::start_next_song\n"; } void start_prev_song(PreviousSong const&) { std::cout << "Playing::start_prev_song\n"; } // guard conditions typedef Playing_ pl; // makes transition table cleaner // Transition table for Playing struct transition_table : mpl::vector4< // Start Event Next Action Guard // +---------+-------------+---------+---------------------+--------------- -------+ a_row < Song1 , NextSong , Song2 , &pl::start_next_song >, a_row < Song2 , PreviousSong, Song1 , &pl::start_prev_song >, a_row < Song2 , NextSong , Song3 , &pl::start_next_song >, a_row < Song3 , PreviousSong, Song2 , &pl::start_prev_song > // +---------+-------------+---------+---------------------+--------------- -------+ > {}; // Replaces the default no-transition response. template <class FSM,class Event> void no_transition(Event const& e, FSM&,int state) { std::cout << "no transition from state " << state << " on event " << typeid(e).name() << std::endl; } }; // back-end typedef msm::back::state_machine<Playing_> Playing; // state not defining any entry or exit struct Paused : public msm::front::state<> { typedef mpl::vector2<PlayingPaused,CDLoaded> flag_list; }; // the initial state of the player SM. Must be defined typedef Empty initial_state; // transition actions void start_playback(play const&) { std::cout << "player::start_playback\n"; } void open_drawer(open_close const&) { std::cout << "player::open_drawer\n"; } void close_drawer(open_close const&) { std::cout << "player::close_drawer\n"; } void store_cd_info(cd_detected const& ) {std::cout << "player::store_cd_info\n";} void stop_playback(stop const&) { std::cout << "player::stop_playback\n"; } void pause_playback(pause const&) { std::cout << "player::pause_playback\n"; } void resume_playback(end_pause const&) { std::cout << "player::resume_playback\n"; } void stop_and_open(open_close const&) { std::cout << "player::stop_and_open\n"; } void stopped_again(stop const&){std::cout << "player::stopped_again\n";} // guard conditions struct isCDLoaded { template <class EVT,class FSM,class SourceState,class TargetState> bool operator()(EVT const& ,FSM& fsm,SourceState& ,TargetState& ) { //return fsm.is_contained(); return fsm.is_flag_active<CDLoaded>(); } }; typedef player_ p; // makes transition table cleaner // Transition table for player struct transition_table : mpl::vector< // Start Event Next Action Guard // +---------+-------------+---------+---------------------+--------------- -------+ a_row < Stopped , play , Playing , &p::start_playback >, Row < Stopped , open_close , Open , none , isCDLoaded >, a_row < Stopped , stop , Stopped , &p::stopped_again >, // +---------+-------------+---------+---------------------+--------------- -------+ a_row < Open , open_close , Empty , &p::close_drawer >, // +---------+-------------+---------+---------------------+--------------- -------+ a_row < Empty , open_close , Open , &p::open_drawer >, a_row < Empty , cd_detected , Stopped , &p::store_cd_info >, // +---------+-------------+---------+---------------------+--------------- -------+ a_row < Playing , stop , Stopped , &p::stop_playback >, a_row < Playing , pause , Paused , &p::pause_playback >, a_row < Playing , open_close , Open , &p::stop_and_open >, // +---------+-------------+---------+---------------------+--------------- -------+ a_row < Paused , end_pause , Playing , &p::resume_playback >, a_row < Paused , stop , Stopped , &p::stop_playback >, a_row < Paused , open_close , Open , &p::stop_and_open > // +---------+-------------+---------+---------------------+--------------- -------+ > {}; // Replaces the default no-transition response. template <class FSM,class Event> void no_transition(Event const& e, FSM&,int state) { std::cout << "no transition from state " << state << " on event " << typeid(e).name() << std::endl; } }; // Pick a back-end typedef msm::back::state_machine<player_> player; // // Testing utilities. // static char const* const state_names[] = { "Stopped", "Open", "Empty", "Playing", "Paused" }; void pstate(player const& p) { std::cout << " -> " << state_names[p.current_state()[0]] << std::endl; } void test() { player p; // needed to start the highest-level SM. This will call on_entry and mark the start of the SM p.start(); // tests some flags std::cout << "CDLoaded active:" << std::boolalpha << p.is_flag_active<CDLoaded>() << std::endl; //=> false (no CD yet) // go to Open, call on_exit on Empty, then action, then on_entry on Open p.process_event(open_close()); pstate(p); p.process_event(open_close()); pstate(p); p.process_event(cd_detected("louie, louie")); p.process_event(play()); // at this point, Play is active std::cout << "PlayingPaused active:" << std::boolalpha << p.is_flag_active<PlayingPaused>() << std::endl;//=> true std::cout << "FirstSong active:" << std::boolalpha << p.is_flag_active<FirstSongPlaying>() << std::endl;//=> true // make transition happen inside it. Player has no idea about this event but it's ok. p.process_event(NextSong());pstate(p); //2nd song active p.process_event(NextSong());pstate(p);//3rd song active p.process_event(PreviousSong());pstate(p);//2nd song active std::cout << "FirstSong active:" << std::boolalpha << p.is_flag_active<FirstSongPlaying>() << std::endl;//=> false std::cout << "PlayingPaused active:" << std::boolalpha << p.is_flag_active<PlayingPaused>() << std::endl;//=> true p.process_event(pause()); pstate(p); std::cout << "PlayingPaused active:" << std::boolalpha << p.is_flag_active<PlayingPaused>() << std::endl;//=> true // go back to Playing // as you see, it starts back from the original state p.process_event(end_pause()); pstate(p); p.process_event(pause()); pstate(p); p.process_event(stop()); pstate(p); std::cout << "PlayingPaused active:" << std::boolalpha << p.is_flag_active<PlayingPaused>() << std::endl;//=> false std::cout << "CDLoaded active:" << std::boolalpha << p.is_flag_active<CDLoaded>() << std::endl;//=> true // event leading to the same state p.process_event(stop()); pstate(p); } } int main() { test(); return 0; }

1 0

boost::hash and string conflicts
by Erik Scorelle 07 Apr '11

07 Apr '11

Hi, We have been using boost hash to hash filenames, but have found with some of our user data that certain strings will produce the same hash code ( "0012g6" and "0012fu" for example). Is there a recommended way to predict or resolve these sorts of conflicts? Thanks in advance!

4 5

[bjam] "Access is denied."
by Phil Bouchard 07 Apr '11

07 Apr '11

Greetings, I am trying to run bjam on Cygwin with the gcc toolset but I keep getting the following error messages: $ bjam toolset=gcc Access is denied. Access is denied. Access is denied. bjam works fine with msvc. Any help is appreciated. Thanks, -Phil

2 2

I just spent most of the day learning about range and lambda.
by Jake Brownson 07 Apr '11

07 Apr '11

Great work guys, those libraries are awesome. Boost makes c++ into a pretty nice place to be. I've been using serialization, preprocessor, and shared_ptr for awhile now which are also pretty great too.

4 3

compilation errors of Parallel BGL
by Da Zheng 07 Apr '11

07 Apr '11

Hello, I try to build Parallel BGL in Ubuntu. I use gcc version 4.4.5, boost v1.46.1, openmpi v1.4.1-3ubuntu1. I believe my environment fulfills your requirements. Then I download parallel-bgl-0.7.0.tar.gz, and try to compile it, but I get some compilation errors. Below shows all my steps of compiling the library. cmake works fine. zhengda@zhengda-desktop:~/graph/parallel-bgl-0.7.0$ BOOST_ROOT=/home/zhengda/graph/boost_1_46_1 cmake . -- The C compiler identification is GNU -- The CXX compiler identification is GNU -- Check for working C compiler: /usr/bin/gcc -- Check for working C compiler: /usr/bin/gcc -- works -- Detecting C compiler ABI info -- Detecting C compiler ABI info - done -- Check for working CXX compiler: /usr/bin/c++ -- Check for working CXX compiler: /usr/bin/c++ -- works -- Detecting CXX compiler ABI info -- Detecting CXX compiler ABI info - done -- Found MPI: /usr/lib/libmpichcxx.so -- Boost version: 1.46.1 -- Found the following Boost libraries: -- mpi -- serialization -- filesystem -- system -- Configuring done -- Generating done -- Build files have been written to: /home/zhengda/graph/parallel-bgl-0.7.0 When I compile the code, it shows the following errors. zhengda@zhengda-desktop:~/graph/parallel-bgl-0.7.0$ make Scanning dependencies of target boost_graph_mpi [ 2%] Building CXX object libs/graph_parallel/src/CMakeFiles/boost_graph_mpi.dir/mpi_process_group.cpp.o In file included from /home/zhengda/graph/parallel-bgl-0.7.0/boost/graph/distributed/mpi_process_group.hpp:807, from /home/zhengda/graph/parallel-bgl-0.7.0/libs/graph_parallel/src/mpi_process_group.cpp:13: /home/zhengda/graph/parallel-bgl-0.7.0/boost/graph/distributed/detail/mpi_process_group.tpp: In function ‘int boost::graph::distributed::receive(const boost::graph::distributed::mpi_process_group&, int, int, T&)’: /home/zhengda/graph/parallel-bgl-0.7.0/boost/graph/distributed/detail/mpi_process_group.tpp:722: error: ‘stderr’ was not declared in this scope /home/zhengda/graph/parallel-bgl-0.7.0/boost/graph/distributed/detail/mpi_process_group.tpp:724: error: there are no arguments to ‘fprintf’ that depend on a template parameter, so a declaration of ‘fprintf’ must be available /home/zhengda/graph/parallel-bgl-0.7.0/boost/graph/distributed/detail/mpi_process_group.tpp:724: note: (if you use ‘-fpermissive’, G++ will accept your code, but allowing the use of an undeclared name is deprecated) /home/zhengda/graph/parallel-bgl-0.7.0/boost/graph/distributed/detail/mpi_process_group.tpp: In function ‘typename boost::enable_if<boost::mpi::is_mpi_datatype<T>, std::pair<int, unsigned int> >::type boost::graph::distributed::receive(const boost::graph::distributed::mpi_process_group&, int, int, T*, size_t)’: /home/zhengda/graph/parallel-bgl-0.7.0/boost/graph/distributed/detail/mpi_process_group.tpp:743: error: ‘stderr’ was not declared in this scope /home/zhengda/graph/parallel-bgl-0.7.0/boost/graph/distributed/detail/mpi_process_group.tpp:745: error: there are no arguments to ‘fprintf’ that depend on a template parameter, so a declaration of ‘fprintf’ must be available /home/zhengda/graph/parallel-bgl-0.7.0/boost/graph/distributed/detail/mpi_process_group.tpp: In function ‘int boost::graph::distributed::receive(const boost::graph::distributed::mpi_process_group&, int, int, T&) [with T = int]’: /home/zhengda/graph/parallel-bgl-0.7.0/boost/graph/distributed/detail/mpi_process_group.tpp:609: instantiated from ‘void boost::graph::distributed::mpi_process_group::global_trigger_launcher<Type, Handler>::receive(const boost::graph::distributed::mpi_process_group&, int, int, boost::graph::parallel::trigger_receive_context, int) const [with Type = int, Handler = void (*)(const boost::graph::distributed::mpi_process_group&, int, int, int, bool)]’ /home/zhengda/graph/parallel-bgl-0.7.0/libs/graph_parallel/src/mpi_process_group.cpp:1110: instantiated from here /home/zhengda/graph/parallel-bgl-0.7.0/boost/graph/distributed/detail/mpi_process_group.tpp:722: error: ‘fprintf’ was not declared in this scope /home/zhengda/graph/parallel-bgl-0.7.0/boost/graph/distributed/detail/mpi_process_group.tpp: In function ‘int boost::graph::distributed::receive(const boost::graph::distributed::mpi_process_group&, int, int, T&) [with T = boost::graph::distributed::mpi_process_group::outgoing_messages]’: /home/zhengda/graph/parallel-bgl-0.7.0/boost/graph/distributed/detail/mpi_process_group.tpp:609: instantiated from ‘void boost::graph::distributed::mpi_process_group::global_trigger_launcher<Type, Handler>::receive(const boost::graph::distributed::mpi_process_group&, int, int, boost::graph::parallel::trigger_receive_context, int) const [with Type = boost::graph::distributed::mpi_process_group::outgoing_messages, Handler = void (*)(const boost::graph::distributed::mpi_process_group&, int, int, boost::graph::distributed::mpi_process_group::outgoing_messages&, bool)]’ /home/zhengda/graph/parallel-bgl-0.7.0/libs/graph_parallel/src/mpi_process_group.cpp:1110: instantiated from here /home/zhengda/graph/parallel-bgl-0.7.0/boost/graph/distributed/detail/mpi_process_group.tpp:722: error: ‘fprintf’ was not declared in this scope make[2]: *** [libs/graph_parallel/src/CMakeFiles/boost_graph_mpi.dir/mpi_process_group.cpp.o] Error 1 make[1]: *** [libs/graph_parallel/src/CMakeFiles/boost_graph_mpi.dir/all] Error 2 make: *** [all] Error 2 So I modify boost/graph/distributed/detail/mpi_process_group.tpp, and insert "#include <stdio.h>". It seems the error above is solved, but I get a new error. This time I don't know how to fix this error. zhengda@zhengda-desktop:~/graph/parallel-bgl-0.7.0$ make [ 2%] Building CXX object libs/graph_parallel/src/CMakeFiles/boost_graph_mpi.dir/mpi_process_group.cpp.o [ 5%] Building CXX object libs/graph_parallel/src/CMakeFiles/boost_graph_mpi.dir/tag_allocator.cpp.o Linking CXX static library ../../../lib/libboost_graph_mpi.a [ 5%] Built target boost_graph_mpi Scanning dependencies of target adjlist_build_test [ 8%] Building CXX object libs/graph_parallel/test/CMakeFiles/adjlist_build_test.dir/adjlist_build_test.cpp.o In file included from /home/zhengda/graph/parallel-bgl-0.7.0/boost/graph/distributed/adjacency_list.hpp:3961, from /home/zhengda/graph/parallel-bgl-0.7.0/libs/graph_parallel/test/adjlist_build_test.cpp:10: /home/zhengda/graph/parallel-bgl-0.7.0/boost/graph/distributed/adjlist/serialization.hpp: In function ‘std::vector<int, std::allocator<int> > boost::detail::parallel::available_process_files(const std::string&)’: /home/zhengda/graph/parallel-bgl-0.7.0/boost/graph/distributed/adjlist/serialization.hpp:97: error: conversion from ‘boost::filesystem3::path’ to non-scalar type ‘std::string’ requested make[2]: *** [libs/graph_parallel/test/CMakeFiles/adjlist_build_test.dir/adjlist_build_test.cpp.o] Error 1 make[1]: *** [libs/graph_parallel/test/CMakeFiles/adjlist_build_test.dir/all] Error 2 make: *** [all] Error 2 Did I do something wrong? Why can I not compile the library? Thanks, Da

3 2

Re: [Boost-users] (no subject)
by Gabriel Marchand 07 Apr '11

07 Apr '11

Thank you for this solution. It compiles. Nevertheless, I still don't achieve what I want to do and I don't understand a few things (I attached the code): 1/ I run the connected_component() function after defining the graph graph_t G(num_nodes) and I expect that there should be as many components as num_nodes as I didn't add the edges yet. However the return of the function tells me there is 1 component ?? After adding the edges between all vertices, the number of components is 1, as it should be. But when I use the function clear_vertex(), I expect to create a new component as the vertex cleaned contain no more edges. The number of components is still one. What I am doing wrong here? 2/I need to know the size in number of vertices of the components, therefore I need to use something like for (i = 0; i != num_nodes; ++i) cout << "Vertex " << i <<" is in component " << component[i] << endl; cout << endl; but of course with our changings done this can't be used. Do you have an idea how I could extract this information. Gabriel --- En date de : Jeu 7.4.11, Cedric Laczny <cedric.laczny(a)gmx.de> a écrit : De: Cedric Laczny <cedric.laczny(a)gmx.de> Objet: Re: [Boost-users] (no subject) À: boost-users(a)lists.boost.org Date: Jeudi 7 avril 2011, 6h50 Alright, now that was a somehow tricky one... Details s. below. On Wednesday, 6. April 2011 12:55:52 Gabriel Marchand wrote: > Hi, I am new to boost and I face the same problem mentioned here with > "connected_components()" using a mutable graph (hence using a list for the > vertex container). I try the detailed solution of Aaron Windsor in the > previous post but I still get some errors at compilation. Here is my > little code: > > > > #include <boost/graph/adjacency_list.hpp> > #include <boost/graph/connected_components.hpp> > > using namespace std; > using namespace boost; > > Box& b = conf.GetBox(); > > > if (!ai) { > ai = new AtomList(); > *ai = conf.GetAtoms().AtomSelector(selecti, b); > } > > typedef boost::adjacency_list< > listS, > listS, > undirectedS, > property<vertex_index_t, size_t>, > no_property> > > > graph_t; > > graph_t g(ai->size()); > property_map<graph_t, vertex_index_t>::type index = get(vertex_index, > g); graph_traits<graph_t>::vertex_iterator vi, vi_end; > graph_traits<graph_t>::vertices_size_type cnt = 0; > for(tie(vi,vi_end) = vertices(g); vi != vi_end; ++vi) > put(index, *vi, cnt++); > > for (unsigned int i = 0; i < ai->size(); ++i) { > Cartesian& crdi = ai->GetElement(i)->pos; > for (unsigned int j = i + 1; j < ai->size(); ++j) { > Cartesian& crdj = ai->GetElement(j)->pos; > double r = conf.GetBox().CartesianDistance(crdi, crdj); > if (r < rcut) { > add_edge(vertex(i,g), vertex(j,g), g); // Add edge to Map > if distance criteria is satisfied > > } > } > } > > vector<int> component(num_vertices(g)); > int num_clusters = connected_components(g, &component[0], > vertex_index_map(index)); > In the example for connected_components() you used, you probably found the "&component[0]" notation and simply used it. However, this does _not_ work for graphs with listS, only for vecS. So basically what you have to do is to define your own components map and _not_ use that wrapper around a vector. As boost seems to model vertices with listS as void* this can hardly work as it is missing the index that it would normally have when using vecS. Also, for vecS, vertices seem to be modeled as int and therefore can serve as indices for vectors directly. So, to make your code compiles, you should use: typedef graph_traits<graph_t>::vertex_descriptor Vertex; map< Vertex, unsigned int > index_std_map; typedef associative_property_map< map< Vertex, unsigned int > > IndexMap; IndexMap index( index_std_map ); // put() the values by iterating over all vertices instead of getting the vertex_index from the graph via "get(vertex_index, G)". With this, you can define your own components-map: vector<int> v_component(num_vertices(G)); iterator_property_map< vector<int>::iterator, IndexMap > component( v_component.begin(), index ); and call connected_components() via: int num_clusters = connected_components(G, component, vertex_index_map(index)); > > > > The compilation is successfull until I add the last line: > int num_clusters = connected_components(g, &component[0], > vertex_index_map(index)); > > > Hope somebody can give a hint > gabriel Hope that I could help and that this solution will be correct for you. Please, of course, test the whole approach in order to make sure it works as you expect it to. Generally it should, as long as the mapping from vertex to index/offset is correct. If there are further questions about the problem or my solution, feel free to mail again. Best, Cedric _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

2 1

Simple Lambda Problem
by Richard Howard 07 Apr '11

07 Apr '11

I am currently trying to get to grips with using Lambda, but I have hit a problem fairly early on. Can anyone explain what I am doing wrong. bool isCar(std::string const & val) { return val.find("car") != std::string::npos; } int main() { std::list<std::string> l; l.push_back("car"); l.push_back("blue car"); l.push_back("red van"); l.push_back("bike"); l.push_back("blue car"); // ... l.remove_if(&isCar); // this works and is how I have done things in the past but I was hoping to avoid the need for the separate function by using Lambda. // I have tried the following l.remove_if(boost::lambda::var(boost::lambda::bind(&std::string::find, boost::lambda::_1, "car")) != std::string::npos); // I am not sure why this does not work, can anyone point me in the right direction? }

2 1

[gil] Processing huge images
by Franz Alt 07 Apr '11

07 Apr '11

Hi all, I'm very new in Boost.GIL so I hope anyone could help me with my question. Imagine several images all with identical dimensions (e.g. 10000x10000). All images form one huge "virtual" image. Because every image is very big (~ 50M) I couldn't copy them together to one image in memory. I want to perform some algorithms (e.g. x-gradient) over the huge image with GIL in a (hopefully) elegant way. The user should use GIL on the huge image "as normal" as possible. Does anyone know how I could handle this problem? Regards Franz

4 6

from matrix to vectors
by Virili 07 Apr '11

07 Apr '11

Hi to all, I'm trying to have a vector (for example a row or a column) from a matrix. like in Matlab : my_column_vector = my_matrix(:,3) or my_row_vector = my_matrix(1,:); I know that it will be a stupid thing, but can you post a reference or a pseudo code?? Thanks!!

2 1

[range] for_each and std::map of std::list
by Mark Snelling 07 Apr '11

07 Apr '11

Hi, Consider a map defined as... std::map< int, std::list< std::string > > my_map; I'm wondering if/how it's possible to use Boost.Range to call a function on each std::string in each of the lists contained in the map. I have an implementation below which works using a C++0x lambda function but am curious if this can be done purely using Boost.Range? boost::for_each( boost::adaptors::values( my_map), []( const std::list< std::string >& my_list ) { boost::for_each( my_list, some_func ); } ); ideas anyone?

5 8

a question on boost::spirit with a quick program.
by Littlefield, Tyler 07 Apr '11

07 Apr '11

Hello all: Sorry for all the questions; I am kind of easing into boost and finding cool things i can do with it, as well as uses for a couple of projects. Eventually I would like to write a small scripting language using boost::spirit, just to do it and get the practice using it. As a starting point, I wrote a quick calculator (that just does small single operations like x+x, x*x, etc). Now i have two questions. 1) My rule seems to be off. the first number comes through clearly, but no matter what I put in, I always get the first number and then a 42. 2) How would I go about extending this to implement order of operations, parenthases, and longer operations (like 3+3*3)? I'm going to try to implement a small function table so I can do tan(3), so I assume I will need nultiple rules, how might that be accomplished? Any comments and suggestions would be welcome. I have pasted the code below. I was working from a tutorial, so early appologies if it feels messy; I plan to clean up the namespace aliases and the using keywords. /* A simple calculator, supports multiplication, division, addition and subtraction. */ #include <boost/spirit/include/qi.hpp> #include <boost/spirit/include/phoenix_core.hpp> #include <boost/spirit/include/phoenix_operator.hpp> #include <boost/spirit/include/phoenix_operator.hpp> #include <iostream> #include <string> #include <boost/fusion/include/adapt_struct.hpp> #include <boost/fusion/container/vector.hpp> #include <boost/fusion/container/vector/convert.hpp> #include <boost/fusion/include/io.hpp> namespace qi = boost::spirit::qi; namespace ascii = boost::spirit::ascii; namespace phoenix = boost::phoenix; using qi::double_; using qi::_1; using ascii::space; using phoenix::ref; using std::cout; using std::endl; typedef struct { int a, b; char op; } calculation; BOOST_FUSION_ADAPT_STRUCT(calculation, (int, a) (int, b) (char, op) ) template <typename iterator> class CParser:public qi::grammar<iterator, calculation(), ascii::space_type> { qi::rule <iterator, calculation(), ascii::space_type> crule; public: CParser():CParser::base_type(crule) { using ascii::char_; using qi::int_; crule %= (int_ >> (char_('+')|char_('-')|char_('*')|char_('/')) >> int_); } }; int main() { using std::cout; using std::cin; using std::endl; using boost::fusion::vector; CParser<std::string::iterator> p; std::string str; calculation result; cout << "Enter your calculation>"; cin >> str; bool r = phrase_parse(str.begin(), str.end(), p, ascii::space, result); if (r) { cout << result.a << " " << result.b << " " << result.op << endl; switch(result.op) { case '+': cout << "Result: " << (result.a + result.b) << endl; break; case '-': cout << "result: " << (result.a - result.b) << endl; break; case '*': cout << "Result: " << (result.a * result.b) << endl; break; case '/': if (result.a == 0) { cout << "Division by zero error." << endl; break; } cout << "result: " << (result.a / result.b) << endl; break; default: cout << "Invalid operation." << endl; } } else { cout << "Invalid input." << endl; } return 0; } -- Thanks, Ty

4 3

[Spirit 2] on_error to string
by Vincent Agnus 07 Apr '11

07 Apr '11

Hi, I have some trouble to retreive error parsing information using qi::on_error<fail> to work on a std::string. The documentation propose the following code : on_error<fail> ( start , std::cout << val("constituent: expected ") << _4 // what failed? << val(" here: \"") << construct<std::string>(_3, _2) // iterators to error-pos, end << val("\"") << std::endl ); * On my First attempt. I have define a class member (std::stringstream m_error) in my grammar class and replace std::cout by phx::ref(m_error). But this code generate a compilation error * For the second attempt, I declare class member m_error as std::string and use this error handler: namespace qi = boost::spirit::qi; namespace phx = boost::phoenix; on_error< qi::fail> ( start , phx::ref(m_error) = ( phx::construct<std::string>(phx::val("Error! Expecting ")) // + qi::_4 REMARK1 + phx::construct<std::string>( phx::val(" here: \"") ) + phx::construct<std::string>(qi::_3, qi::_2) + phx::construct<std::string>( phx::val("\"") ) ) ); that's work perfectly. On error my string is correctly filled. But my problem is that I can't get the expected token (_4) (REMARK1), If I uncomment line REMARK1, I get a compilation error, same result using the code phx::construct<std::string>(qi::_4). How can a get qi::_4 as string ? Can any one with kindness help me?

2 5

(no subject)
by Gabriel Marchand 07 Apr '11

07 Apr '11

Hi, I am new to boost and I face the same problem mentioned here with "connected_components()" using a mutable graph (hence using a list for the vertex container). I try the detailed solution of Aaron Windsor in the previous post but I still get some errors at compilation. Here is my little code: #include <boost/graph/adjacency_list.hpp> #include <boost/graph/connected_components.hpp> using namespace std; using namespace boost; Box& b = conf.GetBox(); if (!ai) { ai = new AtomList(); *ai = conf.GetAtoms().AtomSelector(selecti, b); } typedef boost::adjacency_list< listS, listS, undirectedS, property<vertex_index_t, size_t>, no_property> > graph_t; graph_t g(ai->size()); property_map<graph_t, vertex_index_t>::type index = get(vertex_index, g); graph_traits<graph_t>::vertex_iterator vi, vi_end; graph_traits<graph_t>::vertices_size_type cnt = 0; for(tie(vi,vi_end) = vertices(g); vi != vi_end; ++vi) put(index, *vi, cnt++); for (unsigned int i = 0; i < ai->size(); ++i) { Cartesian& crdi = ai->GetElement(i)->pos; for (unsigned int j = i + 1; j < ai->size(); ++j) { Cartesian& crdj = ai->GetElement(j)->pos; double r = conf.GetBox().CartesianDistance(crdi, crdj); if (r < rcut) { add_edge(vertex(i,g), vertex(j,g), g); // Add edge to Map if distance criteria is satisfied } } } vector<int> component(num_vertices(g)); int num_clusters = connected_components(g, &component[0], vertex_index_map(index)); The compilation is successfull until I add the last line: int num_clusters = connected_components(g, &component[0], vertex_index_map(index)); Hope somebody can give a hint gabriel

2 7

[phoenix] [range] I think I'm missing a couple things w/ these libs
by Jake Brownson 07 Apr '11

07 Apr '11

I love the ideas behind these libs, but I think I need to figure out a bit more before I can use them. Here's an example that models what I'm trying to do for real as an experiment w/ using phoenix and range. I can't quite get it to build. I think I'm really close. I tried it w/ lambda before I found phoenix and I had to do some ret<> things to get past some errors, but I'm not sure what the equivalent in phoenix is, or if I should really need them. Also, I think there should be a way to instantiate a vector directly from a range w/o having to use begin() and end() somehow, but I can't find it. I've tried various approaches with <something> including transformed_range<> and any_range<> and haven't gotten them to work. The transformed line gives me errors complaining about missing result_type, iterator_category, value_type, difference_type, pointer, reference. I'm using GCC 4.2 on OS X Thanks! ---- #include <boost/range/adaptor/transformed.hpp> #include <boost/spirit/include/phoenix_core.hpp> #include <boost/spirit/include/phoenix_bind.hpp> #include <vector> class A {}; class B { public: A a; }; class C { public: static B BFromA(const A& a) { return B(); } }; std::vector<C> CsFromBs(std::vector<B> bs) { <something> cs = bs | boost::adaptors::transformed(boost::phoenix::bind(&C::BFromA, boost::phoenix::bind(&B::a, boost::phoenix::arg_names::arg1))); return std::vector<C>(boost::begin(cs), boost::end(cs)); }

4 9

a quick question regarding extending a class with boost::function
by Littlefield, Tyler 06 Apr '11

06 Apr '11

Hello all: I am working on a mud engine (essentially a game engine), and I had a quick question. I have an event class (yes, I know about boost::signal, but I don't want to go back and it doesn't support delayed events). I would like to set up my event class so that it will take a function object as it's callback, which allows someone extending the engine to add their own content to use global functions, member functions, lambdas, etc etc. Now, here is my problem, and this may be more of a c++ question than a boost question; I'm not really sure. Right now, every time an event gets called, I pass in the object that called it, as well as an EventArgs pointer. So an event callback function might look like this: void OnMouseDown(Object* obj, OnMouseDownArgs* args); Now, it might be useful to have the x and y coordenates where the OnMouseDown event was called, which means I end up doing something like: class OnMouseDownArgs:public EventArgs { public: int x, y; }; which essentially means that for every new type of event, I have to declare an EventArgs class for that. So here was my idea; I thought it would be kind of cool to do something like: Event* OnMouseDown<int, int> = new Event<int, int>(); which leads me to a question. given that template, how would I define a function object with those arguments? better yet, how would I accept an arbitrary number of arguments to the template, then take those arguments and create a boost::function object with them, as well as extend the .Call method to take the arguments I passed in? So in summary, I am trying to extend the boost::function object to accept a set of arguments passed in through a template when the Event object was created, as well as extend the Call method on the Event object to take the two ints as in the MouseDownEvent as arguments. Thanks, Ty

2 2

Boost.Regex Build Failure with CPP Locale and No Win32 on WinXP using Visual Studio 2010 SP1
by David Hauck 06 Apr '11

06 Apr '11

Hello, I'm attempting to build Boost.Regex v1.46.1 with the following user.hpp settings: #define BOOST_REGEX_USE_CPP_LOCALE #define BOOST_REGEX_NO_W32 However, this is failing with the following commands (from the root Boost directory) on WinXP using Visual Studio 2010 SP1: bjam --clean link=shared regex bjam link=shared regex compile-c-c++ bin.v2\libs\regex\build\msvc-10.0\debug\threading-multi\usinstances.obj usinstances.cpp c:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\map(38) : warning C4273: 'id' : inconsistent dll linkage c:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xlocmes(58) : see previous definition of 'public: static std::locale::id std::messages<unsigned short>::id' c:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xlocmes(58) : while compiling class template static data member 'std::locale::id std::messages<_Elem>::id' with [ _Elem=unsigned short ] C:\eng\natools\boost\1_46_1\boost/regex/v4/cpp_regex_traits.hpp(216) : see reference to function template instantiation 'bool std::has_facet<std::messages<_Elem>>(const std::locale &) throw()' being compiled with [ _Elem=unsigned short ] C:\eng\natools\boost\1_46_1\boost/regex/v4/cpp_regex_traits.hpp(211) : while compiling class template member function 'std::locale boost::re_detail::cpp_regex_traits_base<charT>::imbue(const std::locale &)' with [ charT=unsigned short ] C:\eng\natools\boost\1_46_1\boost/regex/v4/cpp_regex_traits.hpp(973) : see reference to function template instantiation 'boost::shared_ptr<T> boost::re_detail::create_cpp_regex_traits<charT>(const std::locale &)' being compiled with [ T=const boost::re_detail::cpp_regex_traits_implementation<unsigned short>, charT=unsigned short ] C:\eng\natools\boost\1_46_1\boost/regex/v4/cpp_regex_traits.hpp(971) : while compiling class template member function 'boost::cpp_regex_traits<charT>::locale_type boost::cpp_regex_traits<charT>::imbue(boost::cpp_regex_traits<charT>::locale_type)' with [ charT=unsigned short ] C:\eng\natools\boost\1_46_1\boost/regex/v4/regex_traits.hpp(74) : see reference to class template instantiation 'boost::cpp_regex_traits<charT>' being compiled with [ charT=unsigned short ] C:\eng\natools\boost\1_46_1\boost/regex/v4/basic_regex.hpp(312) : see reference to class template instantiation 'boost::regex_traits<charT>' being compiled with [ charT=unsigned short ] C:\eng\natools\boost\1_46_1\boost/regex/v4/instances.hpp(90) : see reference to class template instantiation 'boost::basic_regex<charT,traits>' being compiled with [ charT=unsigned short, traits=boost::regex_traits<unsigned short> ] c:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\map(38) : error C2491:'std::messages<_Elem>::id' : definition of dllimport static data member not allowed with [ _Elem=unsigned short ] c:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\map(38) : warning C4273: 'id' : inconsistent dll linkage c:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\locale(48) : see previous definition of 'public: static std::locale::id std::collate<unsigned short>::id' c:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\locale(48) : while compiling class template static data member 'std::locale::id std::collate<_Elem>::id' with [ _Elem=unsigned short ] C:\eng\natools\boost\1_46_1\boost/regex/v4/cpp_regex_traits.hpp(218) : see reference to function template instantiation 'const _Facet &std::use_facet<std::collate<_Elem>>(const std::locale &)' being compiled with [ _Facet=std::collate<unsigned short>, _Elem=unsigned short ] c:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\map(38) : error C2491:'std::collate<_Elem>::id' : definition of dllimport static data member not allowed with [ _Elem=unsigned short ] call "c:\Program Files\Microsoft Visual Studio 10.0\VC\vcvarsall.bat" x86 >nul cl /Zm800 -nologo @"bin.v2\libs\regex\build\msvc-10.0\debug\threading-multi\usinstances.obj.rsp" ...failed compile-c-c++ bin.v2\libs\regex\build\msvc-10.0\debug\threading-multi\usinstances.obj... ...skipped <pbin.v2\libs\regex\build\msvc-10.0\debug\threading-multi>boost_regex-vc100-mt-gd-1_46_1.dll for lack of <pbin.v2\libs\regex\build\msvc-10.0\debug\threading-multi>usinstances.obj... ...skipped <pbin.v2\libs\regex\build\msvc-10.0\debug\threading-multi>boost_regex -vc100-mt-gd-1_46_1.lib for lack of <pbin.v2\libs\regex\build\msvc-10.0\debug\threading-multi>usinstances.obj... ...skipped <pbin.v2\libs\regex\build\msvc-10.0\debug\threading-multi>boost_regex-vc100-mt-gd-1_46_1.pdb for lack of <pbin.v2\libs\regex\build\msvc-10.0\debug\threading-multi>usinstances.obj... ...failed updating 1 target... ...skipped 3 targets... ...updated 16 targets... Any ideas? BTW, ICU is properly identified as not being available. Also, all the previous modules are compiled successfully. Thanks, -David

2 2

Re: [Boost-users] (no subject)
by Gabriel Marchand 06 Apr '11

06 Apr '11

I forgot to attach the code in the previous mail! Here it is. Hi Cedric and thank you for your reply. Actually I need the mutable graph type (using listS as vertex container) because I'll need to use the functions clear_vertex() and remove_vertex(). And I am facing the problem to create this index map property to the vertices to use the function connected_components(). I wrote a more consistent version of the code (test.cpp attached), following the instructions in a previous post by Aaron Windsor: http://boost.2283326.n4.nabble.com/connected-components-td2576097.html It compiles until I added the last line: "int num_clusters = connected_components(G, &component[0], vertex_index_map(index));" The compiler tells: gmarchand@bohr:~/TMP$ g++ test.cpp In file included from /usr/include/c++/4.4/backward/hash_set:60, from /usr/include/boost/graph/adjacency_list.hpp:25, from test.cpp:3: /usr/include/c++/4.4/backward/backward_warning.h:28:2: warning: #warning This file includes at least one deprecated or antiquated header which may be removed without further notice at a future date. Please use a non-deprecated interface with equivalent functionality instead. For a listing of replacement headers and interfaces, consult the file backward_warning.h. To disable this warning use -Wno-deprecated. In file included from /usr/include/boost/graph/adjacency_list.hpp:42, from test.cpp:3: /usr/include/boost/property_map/property_map.hpp: In member function ‘void boost::WritablePropertyMapConcept<PMap, Key>::constraints() [with PMap = int*, Key = void*]’: /usr/include/boost/concept/detail/has_constraints.hpp:40: instantiated from ‘const bool boost::concept::not_satisfied<boost::WritablePropertyMapConcept<int*, void*> >::value’ /usr/include/boost/concept/detail/has_constraints.hpp:43: instantiated from ‘boost::concept::not_satisfied<boost::WritablePropertyMapConcept<int*, void*> >’ /usr/include/boost/mpl/if.hpp:67: instantiated from ‘boost::mpl::if_<boost::concept::not_satisfied<boost::WritablePropertyMapConcept<int*, void*> >, boost::concept::constraint<boost::WritablePropertyMapConcept<int*, void*> >, boost::concept::requirement<boost::WritablePropertyMapConcept<int*, void*> > >’ /usr/include/boost/concept/detail/general.hpp:19: instantiated from ‘boost::concept::requirement_<void (*)(boost::WritablePropertyMapConcept<int*, void*>)>’ /usr/include/boost/concept_check.hpp:43: instantiated from ‘void boost::function_requires(Model*) [with Model = boost::WritablePropertyMapConcept<int*, void*>]’ /usr/include/boost/graph/connected_components.hpp:67: instantiated from ‘typename boost::property_traits<IndexMap>::value_type boost::connected_components(const Graph&, ComponentMap, const boost::bgl_named_params<P, T, R>&, typename boost::enable_if_c<boost::is_base_and_derived::value, boost::graph::detail::no_parameter>::type) [with Graph = main()::graph_t, ComponentMap = int*, P = boost::adj_list_vertex_property_map<boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, long unsigned int, long unsigned int&, boost::vertex_index_t>, T = boost::vertex_index_t, R = boost::no_property]’ test.cpp:54: instantiated from here /usr/include/boost/property_map/property_map.hpp:195: error: no matching function for call to ‘put(int*&, void*&, int&)’ In file included from test.cpp:4: /usr/include/boost/graph/connected_components.hpp: In member function ‘void boost::detail::components_recorder<ComponentsMap>::discover_vertex(Vertex, Graph&) [with Vertex = void*, Graph = const boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, ComponentsMap = int*]’: /usr/include/boost/graph/depth_first_search.hpp:103: instantiated from ‘void boost::detail::depth_first_visit_impl(const IncidenceGraph&, typename boost::graph_traits<Graph>::vertex_descriptor, DFSVisitor&, ColorMap, TerminatorFunc) [with IncidenceGraph = boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, DFSVisitor = boost::detail::components_recorder<int*>, ColorMap = boost::shared_array_property_map<boost::default_color_type, boost::adj_list_vertex_property_map<boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, long unsigned int, long unsigned int&, boost::vertex_index_t> >, TerminatorFunc = boost::detail::nontruth2]’ /usr/include/boost/graph/depth_first_search.hpp:201: instantiated from ‘void boost::depth_first_search(const VertexListGraph&, DFSVisitor, ColorMap, typename boost::graph_traits<Graph>::vertex_descriptor) [with VertexListGraph = boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, DFSVisitor = boost::detail::components_recorder<int*>, ColorMap = boost::shared_array_property_map<boost::default_color_type, boost::adj_list_vertex_property_map<boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, long unsigned int, long unsigned int&, boost::vertex_index_t> >]’ /usr/include/boost/graph/depth_first_search.hpp:296: instantiated from ‘void boost::depth_first_search(const VertexListGraph&, const boost::bgl_named_params<P, T, R>&) [with VertexListGraph = boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, P = boost::detail::components_recorder<int*>, T = boost::graph_visitor_t, R = boost::bgl_named_params<boost::adj_list_vertex_property_map<boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, long unsigned int, long unsigned int&, boost::vertex_index_t>, boost::vertex_index_t, boost::no_property>]’ /usr/include/boost/graph/connected_components.hpp:75: instantiated from ‘typename boost::property_traits<IndexMap>::value_type boost::connected_components(const Graph&, ComponentMap, const boost::bgl_named_params<P, T, R>&, typename boost::enable_if_c<boost::is_base_and_derived::value, boost::graph::detail::no_parameter>::type) [with Graph = main()::graph_t, ComponentMap = int*, P = boost::adj_list_vertex_property_map<boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, long unsigned int, long unsigned int&, boost::vertex_index_t>, T = boost::vertex_index_t, R = boost::no_property]’ test.cpp:54: instantiated from here /usr/include/boost/graph/connected_components.hpp:46: error: no matching function for call to ‘put(int*&, void*&, int&)’ /usr/include/boost/graph/connected_components.hpp: In member function ‘void boost::detail::components_recorder<ComponentsMap>::discover_vertex(Vertex, Graph&) [with Vertex = void*, Graph = boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, ComponentsMap = int*]’: /usr/include/boost/graph/depth_first_search.hpp:38: instantiated from ‘void boost::DFSVisitorConcept<Visitor, Graph>::constraints() [with Visitor = boost::detail::components_recorder<int*>, Graph = boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS>]’ /usr/include/boost/concept/detail/has_constraints.hpp:40: instantiated from ‘const bool boost::concept::not_satisfied<boost::DFSVisitorConcept<boost::detail::components_recorder<int*>, boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS> > >::value’ /usr/include/boost/concept/detail/has_constraints.hpp:43: instantiated from ‘boost::concept::not_satisfied<boost::DFSVisitorConcept<boost::detail::components_recorder<int*>, boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS> > >’ /usr/include/boost/mpl/if.hpp:67: instantiated from ‘boost::mpl::if_<boost::concept::not_satisfied<boost::DFSVisitorConcept<boost::detail::components_recorder<int*>, boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS> > >, boost::concept::constraint<boost::DFSVisitorConcept<boost::detail::components_recorder<int*>, boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS> > >, boost::concept::requirement<boost::DFSVisitorConcept<boost::detail::components_recorder<int*>, boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS> > > >’ /usr/include/boost/concept/detail/general.hpp:19: instantiated from ‘boost::concept::requirement_<void (*)(boost::DFSVisitorConcept<boost::detail::components_recorder<int*>, boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS> >)>’ /usr/include/boost/concept_check.hpp:43: instantiated from ‘void boost::function_requires(Model*) [with Model = boost::DFSVisitorConcept<boost::detail::components_recorder<int*>, boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS> >]’ /usr/include/boost/graph/depth_first_search.hpp:191: instantiated from ‘void boost::depth_first_search(const VertexListGraph&, DFSVisitor, ColorMap, typename boost::graph_traits<Graph>::vertex_descriptor) [with VertexListGraph = boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, DFSVisitor = boost::detail::components_recorder<int*>, ColorMap = boost::shared_array_property_map<boost::default_color_type, boost::adj_list_vertex_property_map<boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, long unsigned int, long unsigned int&, boost::vertex_index_t> >]’ /usr/include/boost/graph/depth_first_search.hpp:296: instantiated from ‘void boost::depth_first_search(const VertexListGraph&, const boost::bgl_named_params<P, T, R>&) [with VertexListGraph = boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, P = boost::detail::components_recorder<int*>, T = boost::graph_visitor_t, R = boost::bgl_named_params<boost::adj_list_vertex_property_map<boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, long unsigned int, long unsigned int&, boost::vertex_index_t>, boost::vertex_index_t, boost::no_property>]’ /usr/include/boost/graph/connected_components.hpp:75: instantiated from ‘typename boost::property_traits<IndexMap>::value_type boost::connected_components(const Graph&, ComponentMap, const boost::bgl_named_params<P, T, R>&, typename boost::enable_if_c<boost::is_base_and_derived::value, boost::graph::detail::no_parameter>::type) [with Graph = main()::graph_t, ComponentMap = int*, P = boost::adj_list_vertex_property_map<boost::adjacency_list<boost::listS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, long unsigned int, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, long unsigned int, long unsigned int&, boost::vertex_index_t>, T = boost::vertex_index_t, R = boost::no_property]’ test.cpp:54: instantiated from here /usr/include/boost/graph/connected_components.hpp:46: error: no matching function for call to ‘put(int*&, void*&, int&)’ gmarchand@bohr:~/TMP$ I hope it is more clear now, Gabriel --- En date de : Mer 6.4.11, Cedric Laczny <cedric.laczny(a)gmx.de> a écrit : De: Cedric Laczny <cedric.laczny(a)gmx.de> Objet: Re: [Boost-users] (no subject) À: boost-users(a)lists.boost.org Date: Mercredi 6 avril 2011, 16h15 Hi, On Wednesday, 6. April 2011 12:55:52 Gabriel Marchand wrote: > Hi, I am new to boost and I face the same problem mentioned here with > "connected_components()" using a mutable graph (hence using a list for the > vertex container). I try the detailed solution of Aaron Windsor in the > previous post but I still get some errors at compilation. Here is my > little code: > > > > #include <boost/graph/adjacency_list.hpp> > #include <boost/graph/connected_components.hpp> > > using namespace std; > using namespace boost; > > Box& b = conf.GetBox(); > You seem to use your own classes and you do not provide the definition. Thus this is unfortunately not a minimal example. So in the future, it might facilitate help from others to you, with this in the back of your head. > > if (!ai) { > ai = new AtomList(); > *ai = conf.GetAtoms().AtomSelector(selecti, b); > } > > typedef boost::adjacency_list< > listS, > listS, > undirectedS, > property<vertex_index_t, size_t>, > no_property> > > > graph_t; > > graph_t g(ai->size()); > property_map<graph_t, vertex_index_t>::type index = get(vertex_index, > g); With listS as the vertex container, I would expect it to fail here. An adjacency_list with listS does not automatically create a vertex_index property. So you might give vecS a try. Especially, if you insert most of the vertices (if not all) at one specific moment and you are not constantly changing the number of vertices in the graph, I think it will make no big difference in performance whether you use vecS or listS. But you have the benefit of automatic vertex_index property-creation. I can however not compile your example (s. above) nor did you provide the error message you get, so I can't tell you for sure if this is the source of error. > graph_traits<graph_t>::vertex_iterator vi, vi_end; > graph_traits<graph_t>::vertices_size_type cnt = 0; > for(tie(vi,vi_end) = vertices(g); vi != vi_end; ++vi) > put(index, *vi, cnt++); > > for (unsigned int i = 0; i < ai->size(); ++i) { > Cartesian& crdi = ai->GetElement(i)->pos; > for (unsigned int j = i + 1; j < ai->size(); ++j) { > Cartesian& crdj = ai->GetElement(j)->pos; > double r = conf.GetBox().CartesianDistance(crdi, crdj); > if (r < rcut) { > add_edge(vertex(i,g), vertex(j,g), g); // Add edge to Map > if distance criteria is satisfied > > } > } > } > > vector<int> component(num_vertices(g)); > int num_clusters = connected_components(g, &component[0], > vertex_index_map(index)); > > > > > The compilation is successfull until I add the last line: > int num_clusters = connected_components(g, &component[0], > vertex_index_map(index)); This confuses me a bit, as I would expect the error in an earlier line. So you might look forward to provide your error message or a really working, minimal example. > > > Hope somebody can give a hint Hope this helps. > gabriel Best, Cedric _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

1 0

write_xml()
by Иван 06 Apr '11

06 Apr '11

Hi, I use write_xml() function and boost-1.46.0-4 on arch linux. void create() { ... out_file.save("/machines/"+name); .... void serializer::save (const std::string &filename) { boost::property_tree::xml_parser::xml_writer_settings<char> gramma(' ',8); write_xml(filename, pt, std::locale(), gramma); } This function don't chroot. readlink -f /proc/5682/cwd /home/iwan Write_xml() create the /machines/+name But it must create a path /home/iwan/machines/+name Why? It is bug? I am sorry for my bad english.

2 1

ASIO port to MQX
by Nick Geoca 06 Apr '11

06 Apr '11

Does anybody know if this has been done or the duration it might take? Thanks Boost Community

1 0

Moderator Query (was: Boost.Regex Build Failure with CPP Locale and No Win32 on WinXP using Visual Studio 2010 SP1)
by David Hauck 06 Apr '11

06 Apr '11

Hello, I'm a new boost-users registrant and had a question regarding the list. Specifically, I sent a message yesterday morning (subject above) that appeared on gmane, but was not received via email. I've checked that I have received all other posts (i.e., gmane and my email for boost-users is consistent other than for the message I sent). Is there any explanation for this (I've verified this message wasn't received locally and marked as spam or otherwise moved by our Exchange server)? Also, I've noticed a couple different subject formats, specifically related to referencing the library name. The policy document suggests referencing libraries as (e.g.) Boost.Regex, but also as (e.g.) [regex] in the subject. It looks like the latter is preferred for subject text. Is this correct? Thanks for your help! -David

4 6

boost interprocess - managed_shared_memory - min segment size
by aidan mcgurn 06 Apr '11

06 Apr '11

Hi, i was wondering what/is there a minimum segment size that can be passed in here: managed_shared_memory(create_only, segmentName, segment size) For example i have seen when i set this to say 30 (30 bytes), i get a segmentation error, not here but on the following line where i try to create the mutex: boost::shared_mutex *mtx = segment.find_or_construct<boost::shared_mutex>("mtx")(); The point been, its not thrown an exception inside managed_shared_memory. However if i set this to 500, then i do get an exception which i catch and print: boost::interprocess_exception::library_error - error_code = 2; native error = 0 Looking at the error codes in error_code_t, 2 = "other_error, // library generated error" So this isn't even a size_error which i can catch and try to resize with? (not sure why this happens then and not for 30 - library generated error code is unclear in this case) If i set this to 700, then it all works fine. So i'm a/ wondering whats going on here b/ is there a minimum segment size? thanks. /aidan

2 1

boost::shared_ptr für symbian
by Ming Lu 06 Apr '11

06 Apr '11

Hello everybody, i used boost::shared_ptr from boost 1.40 for my symbian project. after upgrade of boost to 1.46.0 do i have a compile-error: /In file included from ..//..//dev-environment//libs//cpp//boost//1.46.0/boost/config.hpp:53, from ..//..//dev-environment//libs//cpp//boost//1.46.0/boost/smart_ptr/shared_ptr.hpp:17, from ..//..//dev-environment//libs//cpp//boost//1.46.0/boost/shared_ptr.hpp:17, from ..//..//Core-cpp//inc/CrossSection/Domain/XenoSqlMappedDomainObject.h:20, from ..\\..\\Core-cpp\\src\\CrossSection\\Domain\\Xenosqlmappeddomainobject.cpp:8: ..//..//dev-environment//libs//cpp//boost//1.46.0/boost/config/platform/symbian.hpp:91:4: //*#error "Unsuppoted Symbian SDK"*/ has boost 1.46.0 some changement to make the shared_ptr doesn't support the symbian anymore? what is the last boost version which support symbian open c/c++ SDK? thanks a lot with best regards Ming

1 0

problem compiling filesystem1.46.1 w/ g++ 4.4.3
by Adam Crain 06 Apr '11

06 Apr '11

I just tried to migrate our project from 1.43 -> 1.46.1 but am getting a compilation error with g++ 4.4.3: gcc.compile.c++ bin.v2/libs/filesystem/build/gcc-arm/release/link-static/threading-multi/v3/src/operations.o In file included from boost/filesystem/v3/operations.hpp:25, from libs/filesystem/v3/src/operations.cpp:52: boost/filesystem/v3/path.hpp: In function `std::basic_ostream<_CharT, _Traits>& boost::filesystem3::operator<<(std::basic_ostream<_CharT, _Traits>&, const boost::filesystem3::path&)': boost/filesystem/v3/path.hpp:583: error: parse error before `>' token The build works fine on with microsoft toolchain. Anyone seen this and have a patch? -- *Adam Crain* Chief Platform Architect, GEC Office: 919.836.9916 Cell: 919.428.1002 acrain(a)greenenergycorp.com <abender(a)greenenergycorp.com> *Green Energy Corp,* *enabling the smart grid of the future.** * *www.greenenergycorp.com* *www.totalgrid.org*

1 0

[Asio] Socket Read/Write Thread-Safety
by Timothy Liang 06 Apr '11

06 Apr '11

Hi, I'm implementing a full-duplex protocol over TCP/IP using Boost.Asio. Multiple threads will be calling 'io_service::run_one()', so I have to serialize my completion handlers. Since I need to be reading and writing on a socket at the same time, can I use the 'boost::asio::async_read(...)' and 'boost::asio::async_write(...)' functions? The documentation states that these are implemented in terms of calls to the stream's async_read_some and async_write_some functions, and the 'basic_stream_socket' class isn't thread-safe. Thanks, Timothy

4 15

[fusion] Adding to a map (1.42)
by Noah Roberts 05 Apr '11

05 Apr '11

https://svn.boost.org/trac/boost/ticket/4604 I've got 1.42 though. Updating at this point isn't a good option. Is there a way to work around this so that I can add a new pair to an existing fusion map?

5 6

[lambda] Lambda bind and upgrading
by Swerts, Benjamin 05 Apr '11

05 Apr '11

Hello all, In the process of upgrading Boost from 1.39.0 to 1.46.1 I encountered a few problems with Boost.Lambda. Some places where I used bind and operator== are not compiling anymore with Visual Studio 2008 SP1. Here's a self-contained example showing the problem: --------------------- #include <algorithm> #include <vector> #include <boost/lambda/lambda.hpp> #include <boost/lambda/bind.hpp> using boost::lambda::bind; using boost::lambda::_1; struct A { unsigned int id; }; struct B { const A* a; }; int main() { const std::vector<B> vb; std::find_if(vb.begin(), vb.end(), bind(&A::id, bind(&B::a, _1)) == 2); return 0; } --------------------- - This code compiles fine with Boost 1.39.0 - When compiled with Boost 1.46.1 it shows the following error: boost_1_46_1/boost/lambda/detail/function_adaptors.hpp(280) : error C2440: 'return' : cannot convert from 'const unsigned int' to 'unsigned int &' - When removing the 'const' before the vector, this doesn't even compile in 1.39.0 - What's even stranger is that a simpler version doesn't compile under other circumstances. This compiles with 1.46.1: std::vector<A> va; std::find_if(va.begin(), va.end(), bind(&A::id, _1) == 2); but making the vector const doesn't (exact same error message). Both compile fine with 1.39.0. Both examples compile fine when I use Boost.Bind but that's not always a possible backup plan. I do plan on replacing all the bind calls with their Phoenix v3 equivalents but I first need to get Boost upgraded. Many thanks in advance for any insights. Greets, Ben

2 3

Problems creating unit wrappers with StlSoft
by Ryan 05 Apr '11

05 Apr '11

My current project has several coordinate systems. These include Polar(azimuth, elevation, range) and LLA (latitude, longitude, altitude). I've really enjoyed using boost units to allow the user to input the required unit system but converting them behind the scenes to the unit system I need. I'm developing a function overload that lets the user call a single function but based on the coordinate system given the function behaves differently. Unfortunately, the units for Polar and LLA are the same. Both systems use two plane angles and a length. A second problem is two different groups use two different ways of talking about the Polar coordinate system. One group defines Polar as azimuth, elevation and range while the other group defines Polar as range, azimuth and elevation. I want to give both group the ability to call the function with the Polar definition they are used to talking about. I realize I could create a class for Polar and LLA and then pass that class to my overloaded function. This just pushes off the second problem to the newly created classes. Instead of creating classes for the coordinate systems I wanted to differentiate the different boost units from each other. This would let me overload my function without the need to create larger classes for each coordinate system. I ended up modifying the "true_typedef" class from StlSoft that wraps a type so it becomes incompatible with the same types. This allowed me, for example, to wrap a boost unit plane angle into a longitude and latitude that wouldn't be compatible with each other. What I don't like about this process is having to define a structure type and then using it in the typedef. Is there a boost library that would allow me to create this class in one pass without the two step process? Ryan #define STLSOFT_GEN_OPAQUE(type) typedef struct __stlsoft_htype##{ int i; } const* type; using namespace boost::units; template<typename T, typename U> class BoostUnitQuantityWrapper { typedef T unit_type; typedef U unique_type; typedef BoostUnitQuantityWrapper<T, U> class_type; quantity<unit_type> m_Value; public: template<class System> explicit BoostUnitQuantityWrapper ( quantity< unit< typename unit_type::dimension_type, System> > const& value) : m_Value(quantity<unit_type>(value)) {} BoostUnitQuantityWrapper(class_type const& rhs) : m_Value(rhs.m_Value) {} class_type const& operator= (class_type const& rhs) { m_Value = rhs.m_Value; return *this; } operator quantity<unit_type> () const { return m_Value; } }; STLSOFT_GEN_OPAQUE(latitude_type); STLSOFT_GEN_OPAQUE(longitude_type); STLSOFT_GEN_OPAQUE(range_type); STLSOFT_GEN_OPAQUE(altitude_type); typedef BoostUnitQuantityWrapper<si::plane_angle, latitude_type> Latitude; typedef BoostUnitQuantityWrapper<si::plane_angle, longitude_type> Longitude; typedef BoostUnitQuantityWrapper<si::length, range_type> Range; typedef BoostUnitQuantityWrapper<si::length, altitude_type> Altitude;

1 0

Problem with boost::interprocess::ipc::message_queue
by Ming Lu 05 Apr '11

05 Apr '11

Hello Everybody, i used boost::interprocess::ipc::message_queue (boost 1.40) in my project. it works perfect. after upgrade from boost 1.40.0 to 1.46.0 i do have a problem with the message_queue. my usage of message_queue: Receiver: message_queue message_queue(open_or_create, strQueueName.c_str(), nMessagesNumber, nMessageLength); / .... bReceiveSucces = message_queue.try_receive(pchPuffer, m_nMessageLength, nRecievedSize, nPriority);/ Sender: message_queue message_queue(open_only, m_strMessageQueueName.c_str()); message_queue.try_send(strMessage.c_str(), nMessageLength, nPriority); (the Receiver is running before Sender has be started.) i readed the content in the output windows from Visual Studio 2008 (my building envoriment) during start of my application: * 1.40.0:* /'MessageQueueReceiver.exe': Loaded 'C:\data\20_NoBackup\Project\MessageQueueSender\Debug\MessageQueueReceiver.exe', Symbols loaded./ /'MessageQueueReceiver.exe': Loaded 'C:\WINDOWS\system32\ntdll.dll'/ /'MessageQueueReceiver.exe': Loaded 'C:\WINDOWS\system32\kernel32.dll'/ /'MessageQueueReceiver.exe': Loaded 'C:\WINDOWS\system32\advapi32.dll'/ /'MessageQueueReceiver.exe': Loaded 'C:\WINDOWS\system32\rpcrt4.dll'/ /'MessageQueueReceiver.exe': Loaded 'C:\WINDOWS\system32\secur32.dll'/ /'MessageQueueReceiver.exe': Loaded 'C:\WINDOWS\WinSxS\x86_Microsoft.VC90.DebugCRT_1fc8b3b9a1e18e3b_9.0.21022.8_x-ww_597c3456\msvcr90d.dll', Symbols loaded./ /'MessageQueueReceiver.exe': Loaded 'C:\WINDOWS\WinSxS\x86_Microsoft.VC90.DebugCRT_1fc8b3b9a1e18e3b_9.0.21022.8_x-ww_597c3456\msvcp90d.dll', Symbols loaded./ /'MessageQueueReceiver.exe': Loaded 'C:\WINDOWS\system32\shimeng.dll', Symbols loaded (source information stripped)./ /'MessageQueueReceiver.exe': Unloaded 'C:\WINDOWS\system32\shimeng.dll'/ the receiver-application loaded these dlls and waiting for the input message from the sender-application.. *1.46.0:* /MessageQueueReceiver.exe': Loaded 'C:\WINDOWS\system32\wbem\wbemprox.dll', Symbols loaded (source information stripped)./ /'MessageQueueReceiver.exe': Loaded 'C:\WINDOWS\system32\wbem\wbemcomn.dll', Symbols loaded (source information stripped)./ /'MessageQueueReceiver.exe': Loaded 'C:\WINDOWS\system32\ws2_32.dll', Symbols loaded (source information stripped)./ /'MessageQueueReceiver.exe': Loaded 'C:\WINDOWS\system32\ws2help.dll', Symbols loaded (source information stripped)./ /'MessageQueueReceiver.exe': Loaded 'C:\WINDOWS\system32\wbem\wbemsvc.dll', Symbols loaded (source information stripped)./ /'MessageQueueReceiver.exe': Loaded 'C:\WINDOWS\system32\wbem\fastprox.dll'/ /'MessageQueueReceiver.exe': Loaded 'C:\WINDOWS\system32\msvcp60.dll', Symbols loaded (source information stripped)./ /'MessageQueueReceiver.exe': Loaded 'C:\WINDOWS\system32\ntdsapi.dll', Symbols loaded (source information stripped)./ /'MessageQueueReceiver.exe': Loaded 'C:\WINDOWS\system32\dnsapi.dll'/ /'MessageQueueReceiver.exe': Loaded 'C:\WINDOWS\system32\wldap32.dll', Symbols loaded (source information stripped)./ /'MessageQueueReceiver.exe': Unloaded 'C:\WINDOWS\system32\wbem\fastprox.dll'/ /'MessageQueueReceiver.exe': Unloaded 'C:\WINDOWS\system32\ntdsapi.dll'/ /'MessageQueueReceiver.exe': Unloaded 'C:\WINDOWS\system32\wldap32.dll'/ /'MessageQueueReceiver.exe': Unloaded 'C:\WINDOWS\system32\dnsapi.dll'/ /'MessageQueueReceiver.exe': Unloaded 'C:\WINDOWS\system32\msvcp60.dll'/ /'MessageQueueReceiver.exe': Unloaded 'C:\WINDOWS\system32\wbem\wbemsvc.dll'/ /'MessageQueueReceiver.exe': Unloaded 'C:\WINDOWS\system32\wbem\wbemprox.dll'/ /'MessageQueueReceiver.exe': Unloaded 'C:\WINDOWS\system32\ws2_32.dll'/ /'MessageQueueReceiver.exe': Unloaded 'C:\WINDOWS\system32\ws2help.dll'/ /'MessageQueueReceiver.exe': Unloaded 'C:\WINDOWS\system32\wbem\wbemcomn.dll'/ ...................... ...................... ...................... the receiver-application loaded these complettly different Dlls (in compare with 1.40) and unloaded them repeatly (endless). if man compare the cruise of the message_queue, is 1.46.0 about 4 times slower as 1.40.0. do somebody know? is it a bug or just the sideeffect from the changement? how can i use the message_queue correctly? thanks a lot for any suggestion best regards Ming Lu

3 7

[unit test] problem inside boost UTF
by Bruno Belarte 05 Apr '11

05 Apr '11

Hi, I'm new with boost, and I'm actually experiencing some weird issues... I wrote a class which is basically a wrapper around boost::adjacency_list, and two other nested classes which are wrappers around boost::adjacency_list::vertex_iterator and boost::adjacency_list::out_edge_iterator. I tested theses three classes with the boost unit test framework : everything works fine. Then I wrote a class Tree, which uses boost::shared_/weak_ptr. But when I try to test this class with boost UTF, the test case of the previous graph's out_edge_iterator returns some failures (different depending of the functions from the Tree class called on the test). It's particularly weird considering that these classes share nothing in common except the fact that they use different part of boost. Maybe somebody have a hint on what I am doing wrong !? I used UTF with dynamic lininking, boost1.42 from ubuntu 10.10 package. Thanks, Bruno

3 4

[threads] Deadlock?
by The Novice Coder 05 Apr '11

05 Apr '11

I'm working with boost:threads, and am having what appears to be a deadlock issue. I'm not sure if the lock is something I'm doing, or if it's my lack of understanding of boost::condition_variable. The code deadlocks on this snippit: if( wait) { // lock the condition, add the event, wait for the condition, and get the return value! boost::mutex::scoped_lock lk(serviceMutex_); clearException(); returnValue_ = 0; qApp->postEvent(temp_this, temp_event, Qt::HighEventPriority); serviceCondition_.wait(lk); } Where wait is specified by the caller to wait for the other thread to return. In the service request thread has this snippet: { boost::mutex::scoped_lock lk( serviceMutex_); returnValue_ = qtService(s->getCommand()); serviceCondition_.notify_one(); } I tried it with and without the lock (in the 2nd snippet) but the 2nd snippet code is never getting called and just seems to vanish when wait is specified. When wait isn't specified, it all works. (Non-wait is just the same thing without any of the locks/conditions.) Any thoughts on where to look to proceed or what documents to read ? Thanks, and apologies for the inexperience. New to boost..

3 3

Search and replace in text files with Boost.Xpressive
by Júlio Hoffimann 04 Apr '11

04 Apr '11

What is the better approach with Boost to catch a file with some wildcard-prefixed variables and replace them by numerical values? Example: $ cat file.tmpl ============ var1 = $something ... ... $coord1 $coord2 ... $coordN ... ... ============ $ cat file.dat ============ var1 = 2.35323 ... ... 1.4 3.5 124 910 ... ... ============ The Boost libraries i know for regular expressions are Boost.Regex and Boost.Xpressive. I like the second, because it's header only, has static and dynamic regular expressions and uses it's own namespace. In other words, it incorporates the features of Boost.Regex in a more elegant way. As far as i know, Boost.Xpressive treats only std::string and C-like strings. What i need to do for work with text files? Put them inside a std::string? About the performance, the files has approximately 10^3 lines, the search and replace will be an issue? Regards, Júlio.

3 4

Using boost::shared_ptr with std::set
by przemyslaw.sliwa＠uk.bnpparibas.com 04 Apr '11

04 Apr '11

Hello, I have to use a set of shared pointers to objects. The struct I have to use looks like struct eventIntLim { enum eType { eStart = 0, eEnd }; eType type; double varianceBump; eventIntLim(eType t, double v) : type(t), varianceBump(v) {} bool operator < (const eventIntLim &rhs) const { return fabs(varianceBump) < fabs(rhs.varianceBump); } }; and the definition of the set is typedef boost::shared_ptr<eventIntLim> eventIntLimPtr; typedef std::set<eventIntLimPtr, lessThan> eventIntLimPtrSet; typedef std::map<size_t, eventIntLimPtrSet> eventIntLimMap; In order to sort the objects in the set I have to use the functor struct lessThan : public std::binary_function<boost::shared_ptr<eventIntLim>, boost::shared_ptr<eventIntLim>, bool> { bool operator ()(const boost::shared_ptr<eventIntLim> &lhs, const boost::shared_ptr<eventIntLim> &rhs) const { return (*lhs) < (*rhs); } }; This is quite long and I believe boost can shorten it a lot. I have tried it with boost::lamba and boost::bind but could not make it working. Basically I would like to eliminate the need of writing the definition of struct lessThan. Could someone help me with that? Cheers ___________________________________________________________ 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 unauthorised copying, disclosure or distribution of the material in this e-mail is prohibited. Please refer to http://www.bnpparibas.co.uk/en/information/legal_information.asp?Code=ECAS-… for additional disclosures.

3 3

[MPL] initialization of member that might be non-copyable
by Noah Roberts 04 Apr '11

04 Apr '11

I'm working on something similar to the construct devised in the MPL book Section 9.5 (class composition). Some objects in the composed type might require initialization. I've solved this problem. However, in solving that problem I've now required that any type going into the composition must be copyable. However, since the original composition code doesn't make this requirement I've been trying to find a way to retain the ability to contain types that are non-copyable. Here's some code: template < typename Field > struct field_value { typedef Field field; typedef typename Field::type ftype; ftype value; field_value(ftype const& t) : value(t) {} field_value() : value() {} }; template < typename Field, typename ParamFields, typename Enable = void > struct initializer { template < typename Params > static typename Field::type apply(Params &) { return Field::type(); } }; template < typename Field, typename ParamFields > struct initializer<Field,ParamFields, typename boost::enable_if< boost::mpl::contains<typename Params::fields, typename FieldValue::field> >::type > { template < typename Params > static typename Field::type apply(Params & params) { return get<Field>(params); } }; template < typename FieldValue, typename Params > FieldValue init_field(Params & pars) { return initializer<typename FieldValue::field, typename Params::fields >::apply(pars); } template < typename FieldValue, typename More > struct record_base : FieldValue, More { template < typename Params > record_base(Params & pars) : FieldValue(init_field<FieldValue>(pars)) , More(pars) {} record_base() : FieldValue(), More() {} }; struct empty_record_base { template < typename Ignored > empty_record_base(Ignored&){} empty_record_base() {} }; template < typename MplSequence > struct build_record { typedef boost::mpl::placeholders::_1 _1; typedef boost::mpl::placeholders::_2 _2; typedef typename boost::mpl::fold < MplSequence , empty_record_base , record_base< field_value<_2>, _1 > >::type type; // type should be record_base< field_value<field0> // , record_base< field_value<field1> // , ... record_base<field_value<fieldN>, empty_record_base> // > ... // > }; It's at this point: template < typename Params > record_base(Params & pars) : FieldValue(init_field<FieldValue>(pars)) , More(pars) {} That I need to apply something, I know not what, to correctly initialize the field with either a parameter argument or nothing. I can't think of any construct that would make that possible but I don't necessarily know everything. Is there some way that this can be accomplished?

2 5

[phoenix] lazy function to reference or const reference
by alfC 04 Apr '11

04 Apr '11

Hi, Is it possible to use references as the type of the function wrapped by lazy function. The reason I need this is because I need to instatiate a lazy function inside a class and to a class while the class does not have yet a complete definition. The application may sound exotic but I see no intrinsic limitation why the following doesn't work. If this is not possible because an intrinsic limitation of phoenix, is there a workaround? -- Thanks -- Alfredo ... is_odd_impl is defined as in http://svn.boost.org/svn/boost/sandbox/SOC/2010/phoenix3/libs/phoenix/doc/h… #include<iostream> #include<boost/phoenix/core.hpp> #include<boost/phoenix/function.hpp> using namespace std; using boost::phoenix::arg_names::arg1; int main(){ int cuatro = 4.; is_odd_impl ioi; clog << ioi(cuatro) << endl; boost::phoenix::function<is_odd_impl> fioi; clog << fioi(arg1)(cuatro) << endl; boost::phoenix::function<is_odd_impl&> fioi_ref(ioi); clog << fioi_ref(arg1)(cuatro) << endl; //doesn't compile !!! boost::phoenix::function<is_odd_impl const&> fioi_cref(ioi); clog << fioi_cref(arg1)(cuatro) << endl; //doesn't compile !!! return 0; } example error message: usr/include/boost/phoenix/core/preprocessed/expression_10.hpp:101:17: error: invalid initialization of reference of type ‘const is_odd_impl&’ from expression of type ‘const boost::proto::result_of::make_expr<boost::proto::tag::function, boost::phoenix::default_domain_with_basic_expr, const is_odd_impl, const boost::phoenix::actor<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<boost::phoenix::detail::argument<1> >, 0l> >, void, void, void, void, void, void, void, void, void, void>::type’

2 2

[Thread] Strange problem.
by Germán Diago 04 Apr '11

04 Apr '11

Hello. I'm designing a class with a locking policy. I have some code that does exaclty this: if (cond) { locking_policy_.lock(); out << message.message(); locking_policy_.unlock(); } return *this; And the lockingpolicy is a class like this one: struct ThreadSafe { boost::mutex io_mutex_; boost::unique_lock<boost::mutex> lock_; ThreadSafe() : io_mutex_(), lock_(io_mutex_, boost::defer_lock) {} void lock() { std::cout << "Locking from " << boost::this_thread::get_id() << std::endl; lock_.lock(); } void unlock() { std::cout << "Unlocking from " << boost::this_thread::get_id() << std::endl; lock_.unlock(); } }; Then, I create 3 threads and join them in the same order I created them: boost::thread t1(&doSomething, "Hello1", boost::ref(logsink)); boost::thread t2(&doSomething, "Hello2", boost::ref(logsink)); boost::thread t3(&doSomehting, "Hello3", boost::ref(logsink)); t1.join(); t2.join(); t3.join(); and I get a lock_error. Any help here, please? I can't figure out the problem.

3 3

[asio] port question
by Pace, Antony [Harman Pro Group UK] 04 Apr '11

04 Apr '11

I would like to use boost::asio on my unusual platform which supports Berkeley sockets and has an RTOS and I have full control of low level interrupts etc. I have seen socket_types.hpp and feel that it is likely that I could find a set of defines that match my stack. I also have a timer interrupt that I imagine could be fed into the asio timer somehow but wonder if anyone could tell me how much work I am letting myself in for with that approach or if I would be better off using the Berkeley sockets directly? Many thanks Ant [cid:image001.png@01CBF081.1EA6DAD0] Cranborne House, Cranborne Road, Potters Bar, Herts, EN6 3JN Phone: +44 1707 668025 Email: antony.pace(a)harman.com Skype: antony.pace.harman Web: www.harman.com ANTONY PACE Senior Software Engineer Soundcraft Studer R&D Confidentiality Notice: This e-mail message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorised review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by return e-mail and destroy all copies of the original message.

3 5

[boost::mutex] Suspicious EINVAL error
by Panagiotis Foteinos 03 Apr '11

03 Apr '11

Hello users. I am running a single thread which locks and unlocks mutexes, and I get the following error: * /usr/include/boost/thread/pthread/mutex.hpp:55: void boost::mutex::lock(): Assertion `!pthread_mutex_lock(&m)' failed, *after a boost::shared_mutex::lock() or a boost::shared_mutex::try_lock(). In fact, I checked the error code that pthread_mutex_lock(&m) returned and it was the EINVAL error (code number 22). The posix manual gives 2 possibilities for this error: 1) the mutex has not been properly initialized, or 2) The *mutex* was created with the protocol attribute having the value PTHREAD_PRIO_PROTECT and the calling thread's priority is higher than the mutex's current priority ceiling. Sadly, the mutex is correctly initialized. As far as possibility (2) is concerned, well I cannot interpret it... My code is pretty big, so I cannot provide a complete snippet, but roughly (just in case it helps): **************************************************************************************************** I have the following class: class Vertex { boost::shared_mutex mtx; Vertex() {} }; whose objects call Vertex::mtx->lock(), Vertex::mtx->unlock(), Vertex::mtx->lock_shared(), and Vertex::mtx->unlock_shared(). The above error is produced whenever a specific object (residing in memory) locks or even try_locks its mutex. It always happens for a specific object. **************************************************************************************************** I am using the GNU C++ compiler 4.4.3 on Ubuntu x86_64. I do realize that the information I provide in this email is little, but I, being new in boost::mutexes and having spent so much time on it, decided to give it a shot. Best Regards, Panagiotis Foteinos

2 2

Copy-on-write STL containers
by Alexandr Sterligov 03 Apr '11

03 Apr '11

Is there any interest in a library of STL-compilant containers (vector, deque, map, set, list) with copy-on-write? -- Best regards, Alexander Sterligov

2 1

[BGL] Confusion about iterator_property_map and initialization of OffsetMap
by Cedric Laczny 03 Apr '11

03 Apr '11

Hi, I have modified the astar-cities.cpp example to use an external rank_map based on iterator_property_map. The following should give you an idea: vector<cost> v_vec(num_vertices(g), 0.0); typedef property_map< mygraph_t, vertex_index_t>::type VertexIndexMap; VertexIndexMap v_index = get(vertex_index, g); // Initialization of interest // Create the external property map typedef iterator_property_map< std::vector< cost >::iterator, VertexIndexMap > CostMap; CostMap c_map(v_vec.begin(), v_index); and the function-call of astar_search is as follows: astar_search (g, start, distance_heuristic<mygraph_t, cost, location*, const char**> (locations, goal, name), predecessor_map(&p[0]).distance_map(&d[0]). visitor(a_star_vis). rank_map(c_map)); // Here we use the "global" cost map Basically, the code is the same as in the example, with only the addition of the explicit rank_map. Now I am fairly confused that the function call seems to behave the same if I have "get(vertex_index, g)" and if I don't have it. This comes unexpected to me as I would think that it needs OffsetMap (v_index) to correctly find the index in the random access container (v_vec). But when I simply declare an object it is not yet initialized and will not contain any meaningfull offsets (not using "get(vertex_index, g)"). So why does it work, when the map is not initialized? Or what am I missing here please? Best, Cedric

2 7

[MPL] no invoke<T>?
by Noah Roberts 03 Apr '11

03 Apr '11

I had to write an invoke metafunction because I couldn't seem to find one that looked like it was what I needed: template < typename MF > struct invoke { typedef typename MF::type type; }; I've looked through the documentation TOC: http://www.boost.org/doc/libs/1_42_0/libs/mpl/doc/refmanual/refmanual_toc.h… Is there something I'm missing?

4 8

questions regarding boost::mem_fn and boost::bind
by Littlefield, Tyler 02 Apr '11

02 Apr '11

Hello all: I have a quick question. I was trying to learn how to use boost::mem_fn to work as a sort of function object, because I need something like this for my library. So: If I understand this correctly, it creates a function object that has () overloaded, correct? I was curious if someone could then help me figure this out, the documentation is confusing for me. lets say I have this class: class Foo { public: int Add(int a, int b) { return (a+b); } }; and I could do Foo bar; how would I create a mem_fn named f, that would let me call it for add? so: f(3,1). I would have to tie the instance of foo (bar) to this somehow, correct? Next, I see that mem_fn creates a function object which basically does what I want. What then is the point in boost::bind? It looks to do about the same as mem_fn, just makes my head hurt a little bit more. I am trying to learn boost by finding uses for some of the libraries. Some of them sort of makes sense, but I see that mem_fn are the bases for a lot, so I wanted to learn how to use those. After bind and mem_fn, what other libraries would it be best to learn that is used all over? Last, this is the use I will be putting mem_fn to. If this is incorrect, I still want to learn, but it looked like a great example. I am writing a quick socket class that will have connect, close, and send capabilities. I am hooking this to my game engine, and wanted to use a mem_fn to receive the data. So the server polls all user input, then it will poll the sockets that were added to another list. It will pass off any data read by calling the function object with the data as an argument, as well as the socket. Sorry for all the questions, and thanks in advance for the help/clarification. -- Thanks, Ty

2 1

VS2010+boost 1.44 - error in move.hpp
by archie14 02 Apr '11

02 Apr '11

While compiling the project in VS2010 previously built without errors in VS2008 I am getting following error: c:\libraries\boost\boost_1_44_0\boost\interprocess\detail\move.hpp(342): error C2440: 'return' : cannot convert from 'boost::interprocess::file_mapping' to 'boost::interprocess::file_mapping &&' You cannot bind an lvalue to an rvalue reference c:\libraries\boost\boost_1_44_0\boost\interprocess\file_mapping.hpp (62) : see reference to function template instantiation 'boost::interprocess::file_mapping &&boost::interprocess::move<boost::interprocess::file_mapping&>(T)' being compiled with [ T=boost::interprocess::file_mapping & ] I tried to search the forum for the reports on this error and did not find anything. I'll appreciate any help in this matter.

2 3

[boost] [program options] Potential bug in parsing arguments where one is suffix of the other ?
by Sanjit Jhala 02 Apr '11

02 Apr '11

Hi, I have the following code (modified from example/first.cpp): *#include <boost/program_options.hpp>* *#include <string>* *#include <vector>* *#include <iostream>* * * *namespace po = boost::program_options;* * * *using namespace std;* * * *typedef vector<string> Strings;* * * *// A helper function to simplify the main part.* *template<class T>* *ostream& operator<<(ostream& os, const vector<T>& v)* *{* * copy(v.begin(), v.end(), ostream_iterator<T>(cout, " "));* * return os; * *}* * * * * *int main(int argc, char *argv[]) {* * * * po::options_description cmdline_desc("Usage: %s [Options] [args]\nOptions");* * cmdline_desc.add_options()* * ("str", po::value< string >(), "a string arg")* * ("strs", po::value< Strings >(), "a list of strings")* * ("foo", po::value< string >(), "a string arg")* * ("bar", po::value< Strings >(), "a list of strings")* * ; * * * * po::variables_map vm; * * po::store(po::parse_command_line(argc, argv, cmdline_desc), vm);* * po::notify(vm);* * * * if (vm.count("str"))* * cout << "Got str arg=" << vm["str"].as< string >() << "\n";* * if (vm.count("strs"))* * cout << "Got strs arg=" << vm["strs"].as< Strings >() << "\n";* * if (vm.count("foo"))* * cout << "Got foo arg=" << vm["foo"].as< string >() << "\n";* * if (vm.count("bar"))* * cout << "Got bar arg=" << vm["bar"].as< Strings >() << "\n";* *}* * * When I run the program I see: *./po_test --str "a string" --strs "a, vector, of, strings" --foo "a foo" --bar "a, bar"* *Got strs arg=a string a, vector, of, strings * *Got foo arg=a foo* *Got bar arg=a, bar * It appears the parser is getting confused between the "str" and the "strs". It doesn't seem to be related to ambiguity in handling vectors since the "foo" and "bar" arguments are fine. I see this problem on 32-bit CentOS and Ubuntu machines, but not on 64-bit. I am running Boost 1.43 and from the /usr/local/include/boost/program_options/version.hpp: #define BOOST_PROGRAM_OPTIONS_VERSION_HPP_VP_2004_04_05 #define BOOST_PROGRAM_OPTIONS_VERSION 2 Is this a bug or a expected behaviour? -Sanjit

2 2

Boost Graph/Subgraph: Making a "layered graph"
by Frank Neuhaus 02 Apr '11

02 Apr '11

Hi, I want to represent a graph that consists of several layers. I have an algorithm that is supposed to be run on each layer seperately. I thought about having all layers in one graph, but each layer in a subgraph of this graph. That way - I thought - I could leave the algorithm that works on one layer unchanged. First off: Is that a reasonable design? Is there a different way to achieve what I want? Maybe there is another way to pass a subset of the graph to my algorithm? Now as for the actual problem with boost subgraphs: My current code (for one layer only) looks similar to this: ---- struct my_vertex { int x; }; struct my_edge { int y; }; typedef boost::adjacency_list<vecS, listS, undirectedS, my_vertex, my_edge> NormalGraph; NormalGraph ng; NormalGraph::vertex_descriptor vd=add_vertex(ng); ng[vd].x=5; ---- So as you can see I am using bundled properties. Now I want to create the same thing with subgraphs. Just doing ---- typedef boost::subgraph<boost::adjacency_list<vecS, listS, undirectedS, my_vertex, my_edge> > SubGraph; ---- Did not work and I suspected it was due to the problem mentioned in the "Notes" section at the very bottom of [1] - which I dont quite understand to be honest. I still tried to use the workaround that is mentioned there: ---- struct my_vertex { int x; }; struct my_edge { int y; }; typedef boost::property<boost::vertex_index_t, std::size_t, my_vertex> vertex_prop; typedef boost::property<boost::edge_index_t, std::size_t, my_edge> edge_prop; typedef boost::adjacency_list<vecS, listS, undirectedS, vertex_prop, edge_prop> Graph; typedef boost::subgraph<Graph> Subgraph; Subgraph sg; Subgraph::vertex_descriptor vd=add_vertex(sg); sg[vd].x=5; // doesnt work - why? auto pm=get(boost::vertex_bundle,sg); my_vertex vert; vert.x=7; put(pm,vd,vert); // doesnt work - why? ---- Now I do not understand how to access my vertex and edge properties as you can see... Neither using [] nor accessing via property maps appears to work. What am I doing wrong here? I couldnt find any documentation or examples on this :( Thanks a lot Frank [1] http://www.boost.org/doc/libs/1_46_0/libs/graph/doc/subgraph.html

2 1

[Graph] Topological sort compilation error
by Bruno Morais 01 Apr '11

01 Apr '11

Hi, I got some problems trying to compile a topological sort code. I created my graph with the color properties but I got the error: error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'boost::detail::error_property_not_found' (or there is no acceptable conversion) So, I tried the example at boost_1_46_1\libs\graph\example\topo_sort.cpp. It works fine, but with a little change I could reproduce the error. I change the following code at line 43: typedef adjacency_list<vecS, vecS, directedS, property<vertex_color_t, default_color_type> > Graph; to typedef adjacency_list<vecS, listS, directedS, property<vertex_color_t, default_color_type> > Graph; Should the vertex list selector influence on that? I tried Boost 1.46.1 and got the error with both compilers: Microsot Visual Studio 2008 version 9.0.21022.8 RTM and Intel® C++ Compiler Version 11.1.850.2008 I attached the modified version of the file. With Kind Regards, Bruno

2 1

Re: [Boost-users] Boost-users Digest, Vol 2679, Issue 1
by Shah, Gaurav N 01 Apr '11

01 Apr '11

Thanks Andreas Wehrmann. if worked after including boost/function.hpp. I am still wondering what changes boost has made while moving from 1.41 to 1.44 that has made users to explicitly include "function.hpp" This code was compiling with 1.41 without including boost/function.hpp Thank You, Gaurav -----Original Message----- From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of boost-users-request(a)lists.boost.org Sent: Friday, April 01, 2011 11:34 AM To: boost-users(a)lists.boost.org Subject: Boost-users Digest, Vol 2679, Issue 1 Send Boost-users mailing list submissions to boost-users(a)lists.boost.org To subscribe or unsubscribe via the World Wide Web, visit http://lists.boost.org/mailman/listinfo.cgi/boost-users or, via email, send a message with subject or body 'help' to boost-users-request(a)lists.boost.org You can reach the person managing the list at boost-users-owner(a)lists.boost.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Boost-users digest..." Today's Topics: 1. Re: [boost::mutex] Do they block or wait? (Ovanes Markarian) 2. Re: [Lambda] nitty gritty detail...? (Robert Jones) 3. Re: [Lambda] nitty gritty detail...? (Steven Watanabe) 4. VS2010+boost 1.44 - error in move.hpp (archie14) 5. [boost] [program options] Potential bug in parsing arguments where one is suffix of the other ? (Sanjit Jhala) 6. [MPL] no invoke<T>? (Noah Roberts) 7. Re: Problem with gcc/4.5.0-g++and boost::function (Andreas Wehrmann) ---------------------------------------------------------------------- Message: 1 Date: Thu, 31 Mar 2011 20:21:29 +0200 From: Ovanes Markarian <om_boost(a)keywallet.com> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] [boost::mutex] Do they block or wait? Message-ID: <AANLkTim_=MZAk0WwoerK7-TCRAGpN0Gdgcr+DDV5uhOA(a)mail.gmail.com> Content-Type: text/plain; charset="iso-8859-1" On Thu, Mar 31, 2011 at 7:49 PM, Steven Watanabe <watanabesj(a)gmail.com>wrote: > AMDG > > > On 03/31/2011 09:55 AM, Panagiotis Foteinos wrote: > >> I looked into the documentation, but it is still unclear to me. >> >> [...] > > boost's locking mechanism >> blocking or spinning? >> >> > It's an implementation detail. You realize that the > two aren't necessarily mutually exclusive? Anyway, > Boost.Thread does block on an Event. A spin-lock > only makes sense on a multi-core system. > > In Christ, > Steven Watanabe > As Steven pointed out it is an implementation detail and these two concepts might be used together (primarily for optimization). Switching to kernel mode (e.g. dealing with kernel objects like event, mutex, semaphore through system calls) is a very time costly operation, therefore some libs provide spinning optimizations, which do spinning (for some few cpu cycles) and if they are still unable to acquire a lock, they make a system call which changes into the kernel mode and finally puts the thread into the blocked state if the object is still not available (signaled, unlocked etc). But even so it is not black and white in the concurrency world. :( Some would like to achieve speed through such an optimization others would like to get rid of such an optimization. A good example might be an embedded app running on a battery driven HW, where energy plays a major role. Here wasting CPU cycles for speed optimization might not be a good idea... But anyway that should be separately evaluated. With Kind Regards, Ovanes -------------- next part -------------- HTML attachment scrubbed and removed ------------------------------ Message: 2 Date: Thu, 31 Mar 2011 19:27:30 +0100 From: Robert Jones <robertgbjones(a)gmail.com> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] [Lambda] nitty gritty detail...? Message-ID: <AANLkTinfsOJmqrWBP16+7s2c+YufKcW3GwcHapxttLqq(a)mail.gmail.com> Content-Type: text/plain; charset="iso-8859-1" On Thu, Mar 31, 2011 at 4:47 PM, Steven Watanabe <watanabesj(a)gmail.com>wrote: > AMDG > > > On 03/31/2011 08:29 AM, Robert Jones wrote: > >> From Bjorn Karlsson's book, P297... >>> >> >> int i; >> int value = 12; >> var(i) = ( if_then_else_return( _1>=10, constant(10),_1) )(value); >> >> Why does the assignment LHS need to be wrapped in var()? >> >> > Because operator= must be a member function. > > Nope, still not getting it! Stop me when I err... if_then_else_return(...) defines a unary functor it_then_else_return(...)( value) evaluates that functor, and returns what? Some type of integer I think? So doesn't the assignment simply perform assignment of an integer, by copy? And that doesn't need operator= to a member of anything? Thanks - R. -------------- next part -------------- HTML attachment scrubbed and removed ------------------------------ Message: 3 Date: Thu, 31 Mar 2011 11:38:33 -0700 From: Steven Watanabe <watanabesj(a)gmail.com> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] [Lambda] nitty gritty detail...? Message-ID: <4D94CA29.9060307(a)providere-consulting.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed AMDG On 03/31/2011 11:27 AM, Robert Jones wrote: > On Thu, Mar 31, 2011 at 4:47 PM, Steven Watanabe<watanabesj(a)gmail.com>wrote: >> >> On 03/31/2011 08:29 AM, Robert Jones wrote: >> >>> From Bjorn Karlsson's book, P297... >>>> >>> >>> int i; >>> int value = 12; >>> var(i) = ( if_then_else_return( _1>=10, constant(10),_1) )(value); >>> >>> Why does the assignment LHS need to be wrapped in var()? >>> >>> >> Because operator= must be a member function. >> >> > Nope, still not getting it! Stop me when I err... > > if_then_else_return(...) defines a unary functor > it_then_else_return(...)( value) evaluates that functor, and returns what? > > Some type of integer I think? Yes. > So doesn't the assignment simply perform > assignment of an integer, by copy? And that doesn't need operator= to > a member of anything? > Oh, I see. As written, the code doesn't make much sense, so my mind automatically translated it into (var(i) = if_then_else_return( _1>=10, constant(10),_1) )(value); In Christ, Steven Watanabe ------------------------------ Message: 4 Date: Thu, 31 Mar 2011 22:56:11 +0000 (UTC) From: archie14 <admin(a)tradeplatform.us> To: boost-users(a)lists.boost.org Subject: [Boost-users] VS2010+boost 1.44 - error in move.hpp Message-ID: <loom.20110401T005027-111(a)post.gmane.org> Content-Type: text/plain; charset=us-ascii While compiling the project in VS2010 previously built without errors in VS2008 I am getting following error: c:\libraries\boost\boost_1_44_0\boost\interprocess\detail\move.hpp(342): error C2440: 'return' : cannot convert from 'boost::interprocess::file_mapping' to 'boost::interprocess::file_mapping &&' You cannot bind an lvalue to an rvalue reference c:\libraries\boost\boost_1_44_0\boost\interprocess\file_mapping.hpp (62) : see reference to function template instantiation 'boost::interprocess::file_mapping &&boost::interprocess::move<boost::interprocess::file_mapping&>(T)' being compiled with [ T=boost::interprocess::file_mapping & ] I tried to search the forum for the reports on this error and did not find anything. I'll appreciate any help in this matter. ------------------------------ Message: 5 Date: Thu, 31 Mar 2011 16:16:25 -0700 From: Sanjit Jhala <sjhalaz(a)gmail.com> To: boost-users(a)lists.boost.org Subject: [Boost-users] [boost] [program options] Potential bug in parsing arguments where one is suffix of the other ? Message-ID: <AANLkTi=bEJWMhNj-wO-9O6SjHORiGkr0xn75pKeJOU4=(a)mail.gmail.com> Content-Type: text/plain; charset="iso-8859-1" Hi, I have the following code (modified from example/first.cpp): *#include <boost/program_options.hpp>* *#include <string>* *#include <vector>* *#include <iostream>* * * *namespace po = boost::program_options;* * * *using namespace std;* * * *typedef vector<string> Strings;* * * *// A helper function to simplify the main part.* *template<class T>* *ostream& operator<<(ostream& os, const vector<T>& v)* *{* * copy(v.begin(), v.end(), ostream_iterator<T>(cout, " "));* * return os; * *}* * * * * *int main(int argc, char *argv[]) {* * * * po::options_description cmdline_desc("Usage: %s [Options] [args]\nOptions");* * cmdline_desc.add_options()* * ("str", po::value< string >(), "a string arg")* * ("strs", po::value< Strings >(), "a list of strings")* * ("foo", po::value< string >(), "a string arg")* * ("bar", po::value< Strings >(), "a list of strings")* * ; * * * * po::variables_map vm; * * po::store(po::parse_command_line(argc, argv, cmdline_desc), vm);* * po::notify(vm);* * * * if (vm.count("str"))* * cout << "Got str arg=" << vm["str"].as< string >() << "\n";* * if (vm.count("strs"))* * cout << "Got strs arg=" << vm["strs"].as< Strings >() << "\n";* * if (vm.count("foo"))* * cout << "Got foo arg=" << vm["foo"].as< string >() << "\n";* * if (vm.count("bar"))* * cout << "Got bar arg=" << vm["bar"].as< Strings >() << "\n";* *}* * * When I run the program I see: *./po_test --str "a string" --strs "a, vector, of, strings" --foo "a foo" --bar "a, bar"* *Got strs arg=a string a, vector, of, strings * *Got foo arg=a foo* *Got bar arg=a, bar * It appears the parser is getting confused between the "str" and the "strs". It doesn't seem to be related to ambiguity in handling vectors since the "foo" and "bar" arguments are fine. I see this problem on 32-bit CentOS and Ubuntu machines, but not on 64-bit. I am running Boost 1.43 and from the /usr/local/include/boost/program_options/version.hpp: #define BOOST_PROGRAM_OPTIONS_VERSION_HPP_VP_2004_04_05 #define BOOST_PROGRAM_OPTIONS_VERSION 2 Is this a bug or a expected behaviour? -Sanjit -------------- next part -------------- HTML attachment scrubbed and removed ------------------------------ Message: 6 Date: Thu, 31 Mar 2011 16:32:13 -0700 From: Noah Roberts <roberts.noah(a)gmail.com> To: boost-users(a)lists.boost.org Subject: [Boost-users] [MPL] no invoke<T>? Message-ID: <in32tm$6u3$1(a)dough.gmane.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed I had to write an invoke metafunction because I couldn't seem to find one that looked like it was what I needed: template < typename MF > struct invoke { typedef typename MF::type type; }; I've looked through the documentation TOC: http://www.boost.org/doc/libs/1_42_0/libs/mpl/doc/refmanual/refmanual_toc.h… Is there something I'm missing? ------------------------------ Message: 7 Date: Fri, 01 Apr 2011 08:04:18 +0200 From: Andreas Wehrmann <a.wehrmann(a)centersystems.com> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] Problem with gcc/4.5.0-g++and boost::function Message-ID: <4D956AE2.4040808(a)centersystems.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed On 03/31/2011 06:42 PM, Steven Watanabe wrote: > AMDG > > On 03/31/2011 09:27 AM, Shah, Gaurav N wrote: >> I have legacy code in my library using boost::function. This works >> fine if I am using gcc/4.2.2-g++ and BOOST/1.41. But if I switch >> myself to using gcc/4.5.0-g++ and BOOST/1.44 I get below ERROR: >> I do not see anything wrong with code. >> >> /export/home/a_besnad/Perforce/eq-thebeast-build-linux-Beast_8.08/TheBeast/marketdata/IMDMXP/server/wombat/management.hpp:69:51: >> error: 'function' in namespace 'boost' does not name a type >> /export/home/a_besnad/Perforce/eq-thebeast-build-linux-Beast_8.08/TheBeast/marketdata/IMDMXP/server/wombat/management.hpp:69:58: >> error: ISO C++ forbids declaration of 'parameter' with no type >> /export/home/a_besnad/Perforce/eq-thebeast-build-linux-Beast_8.08/TheBeast/marketdata/IMDMXP/server/wombat/management.hpp:69:66: >> error: expected ',' or '...' before '<' token >> ../../../../../../marketdata/IMDMXP/server/wombat/management.cpp:126:10: >> error: prototype for 'void datasource::management::stop(const >> std::string&, const boost::function<void()>&)' does not match any in >> class 'datasource::management' >> /export/home/a_besnad/Perforce/eq-thebeast-build-linux-Beast_8.08/TheBeast/marketdata/IMDMXP/server/wombat/management.hpp:69:14: >> error: candidate is: void datasource::management::stop(const >> std::string&, int) >> make[6]: *** [management.lo] Error 1 >> make[6]: *** Waiting for unfinished jobs.... >> >> >> >> Code lines throw ERROR: >> >> 68 */ >> 69 void stop(const std::string& topic, const >> boost::function< void (void)>& action); >> 70 >> >> Thanks for help in advance. >> > > Have you verified that boost/function.hpp > is #included? > > In Christ, > Steven Watanabe > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users This is the first thing I would check, since the compiler has become stricter, meaning indirect inclusions won't work anymore. I ran across the same problem when upgrading from 4.2.x to 4.4.x and 4.5.x respectively. Regards, Andreas -- Dipl.-Ing. (FH) Andreas Wehrmann Software Development -------------------------------------------------------------- Center Communication Systems GmbH A-1210 Wien, Ignaz-K?ck-Stra?e 19 Sitz in Wien FN 796 88p, Firmenbuchgericht Wien www.centersystems.com Tel.: +43 (0) 190 199 - 3616 Mobile: +43 (0) 664 884 75916 Fax: +43 (0) 190 199 - 2110 E-Mail: a.wehrmann(a)centersystems.com ------------------------------ _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users End of Boost-users Digest, Vol 2679, Issue 1 ******************************************** This communication is for informational purposes only. It is not intended as an offer or solicitation for the purchase or sale of any financial instrument or as an official confirmation of any transaction. All market prices, data and other information are not warranted as to completeness or accuracy and are subject to change without notice. Any comments or statements made herein do not necessarily reflect those of JPMorgan Chase & Co., its subsidiaries and affiliates. This transmission may contain information that is privileged, confidential, legally privileged, and/or exempt from disclosure under applicable law. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution, or use of the information contained herein (including any reliance thereon) is STRICTLY PROHIBITED. Although this transmission and any attachments are believed to be free of any virus or other defect that might affect any computer system into which it is received and opened, it is the responsibility of the recipient to ensure that it is virus free and no responsibility is accepted by JPMorgan Chase & Co., its subsidiaries and affiliates, as applicable, for any loss or damage arising in any way from its use. If you received this transmission in error, please immediately contact the sender and destroy the material in its entirety, whether in electronic or hard copy format. Thank you. Please refer to http://www.jpmorgan.com/pages/disclosures for disclosures relating to European legal entities.

2 1

how to link to a specific version of windows CRT
by Mai Zi 01 Apr '11

01 Apr '11

Hi,there, I am using boost 1.42. The default CRT linked by it is like this: name='Microsoft.VC90.CRT' version='9.0.21022.8' Now I want to link to the another version, say, version="9.0.30729.4148", can anybody tell where and how to specify this option when I build the binary from source? Thanks in advance OrNot

4 3

gcc3.4 and boost type trait (is_virtual_base_of) , compile warning
by emeplease 01 Apr '11

01 Apr '11

Hello , I am using boost 1.41 with gcc 3.4 (I know it's pretty old) , I am having problem with "is_virtual_base_of" The following lines of code will reproduce the problem. Thank you very much Joseph ======== test_typetrait.cpp ============== #include <iostream> #include <boost/type_traits/is_virtual_base_of.hpp> class Fruit { }; class Apple : virtual public Fruit { }; int main(int argc,char** argv) { std::cout << std::endl << boost::is_virtual_base_of< Fruit, Apple>::value << std::endl; return 0; } ======== full Compile warning ============== include/boost/type_traits/is_virtual_base_of.hpp: In instantiation of `boost::detail::is_virtual_base_of_impl<Fruit, Apple, mpl_::bool_< true> >::X': include/boost/type_traits/is_virtual_base_of.hpp:70: instantiated from `boost::detail::is_virtual_base_of_impl<Fruit, Apple, mpl_::bool_< true> >' include/boost/type_traits/is_virtual_base_of.hpp:78: instantiated from `boost::detail::is_virtual_base_of_impl2<Fruit, Apple>' include/boost/type_traits/is_virtual_base_of.hpp:87: instantiated from `boost::is_virtual_base_of<Fruit, Apple>' test_typetrait.cpp:119: instantiated from here include/boost/type_traits/is_virtual_base_of.hpp:56: warning: direct base `Fruit' inaccessible in `boost::detail::is_virtual_base_of_impl<Fruit, Apple, mpl_::bool_< true> >::X' due to ambiguity

2 1

Problem with gcc/4.5.0-g++and boost::function
by Shah, Gaurav N 01 Apr '11

01 Apr '11

I have legacy code in my library using boost::function. This works fine if I am using gcc/4.2.2-g++ and BOOST/1.41. But if I switch myself to using gcc/4.5.0-g++ and BOOST/1.44 I get below ERROR: I do not see anything wrong with code. /export/home/a_besnad/Perforce/eq-thebeast-build-linux-Beast_8.08/TheBeast/marketdata/IMDMXP/server/wombat/management.hpp:69:51: error: 'function' in namespace 'boost' does not name a type /export/home/a_besnad/Perforce/eq-thebeast-build-linux-Beast_8.08/TheBeast/marketdata/IMDMXP/server/wombat/management.hpp:69:58: error: ISO C++ forbids declaration of 'parameter' with no type /export/home/a_besnad/Perforce/eq-thebeast-build-linux-Beast_8.08/TheBeast/marketdata/IMDMXP/server/wombat/management.hpp:69:66: error: expected ',' or '...' before '<' token ../../../../../../marketdata/IMDMXP/server/wombat/management.cpp:126:10: error: prototype for 'void datasource::management::stop(const std::string&, const boost::function<void()>&)' does not match any in class 'datasource::management' /export/home/a_besnad/Perforce/eq-thebeast-build-linux-Beast_8.08/TheBeast/marketdata/IMDMXP/server/wombat/management.hpp:69:14: error: candidate is: void datasource::management::stop(const std::string&, int) make[6]: *** [management.lo] Error 1 make[6]: *** Waiting for unfinished jobs.... Code lines throw ERROR: 68 */ 69 void stop(const std::string& topic, const boost::function< void (void)>& action); 70 Thanks for help in advance. Thank You, Gaurav This communication is for informational purposes only. It is not intended as an offer or solicitation for the purchase or sale of any financial instrument or as an official confirmation of any transaction. All market prices, data and other information are not warranted as to completeness or accuracy and are subject to change without notice. Any comments or statements made herein do not necessarily reflect those of JPMorgan Chase & Co., its subsidiaries and affiliates. This transmission may contain information that is privileged, confidential, legally privileged, and/or exempt from disclosure under applicable law. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution, or use of the information contained herein (including any reliance thereon) is STRICTLY PROHIBITED. Although this transmission and any attachments are believed to be free of any virus or other defect that might affect any computer system into which it is received and opened, it is the responsibility of the recipient to ensure that it is virus free and no responsibility is accepted by JPMorgan Chase & Co., its subsidiaries and affiliates, as applicable, for any loss or damage arising in any way from its use. If you received this transmission in error, please immediately contact the sender and destroy the material in its entirety, whether in electronic or hard copy format. Thank you. Please refer to http://www.jpmorgan.com/pages/disclosures for disclosures relating to European legal entities.

3 2

[Lambda] nitty gritty detail...?
by Robert Jones 31 Mar '11

31 Mar '11

>From Bjorn Karlsson's book, P297... int i; int value = 12; var(i) = ( if_then_else_return( _1>=10, constant(10),_1) )(value); Why does the assignment LHS need to be wrapped in var()? Thanks in advance - Rob.

2 3

[boost::mutex] Do they block or wait?
by Panagiotis Foteinos 31 Mar '11

31 Mar '11

Hello users. I looked into the documentation, but it is still unclear to me. When a thread locks() an already acquired mutex, does it block (i.e. does it do nothing?) releasing all the resources or it loops wasting cpu cycles that another thread could utilize? In other words, is boost's locking mechanism blocking or spinning? Best Regards, Panagiotis Foteinos

3 2

[context review] Review is finished
by Vicente BOTET 31 Mar '11

31 Mar '11

Hi all, As there were no request to extend the review, the review of Oliver Kowalke Context library is finished. I think that even if there were not too much review and discussions, there were enough material to make Boost.Context a library having the Boost level. I hope I could be able to give the review result soon. I would like to thank Oliver and of course all the reviewers for their participation I'm afraid there was some problems with User ML. If you think that you could made a review next weekend, please don't hesitate to send it to the Dev ML. Vicente, Review manager

1 0

no log file created
by list_mailing＠libero.it 31 Mar '11

31 Mar '11

Hello. I'm using init_from_settings method, setting logging to file. The problem is that everything seems ok, but no log file is created. Please can someone help to find the problem? Cheers

1 0

BOOST.LOG inti_from_setting core dumped
by list_mailing＠libero.it 31 Mar '11

31 Mar '11

Hello to all, Using init_from_settings method I get a core dump. ./test_logging Filename:log.log terminate called after throwing an instance of 'boost::exception_detail:: clone_impl<boost::exception_detail::error_info_injector<boost::log_mt_posix:: missing_value> >' what(): File name is not specified Aborted (core dumped) As you can read, the Filename value is correctly set. Any suggestion to fix it? Below the source code for the program test_logging: #include <string> #include <sstream> #include <ostream> #include <fstream> #include <boost/any.hpp> #include <boost/log/trivial.hpp> #include <boost/log/utility/init/from_settings.hpp> #include <boost/log/attributes.hpp> #include <sensor_options.hpp> using namespace boost::log; namespace src = boost::log::sources; using namespace std; ostream* stream_null = new ofstream("/dev/null"); class MyClass { public: MyClass(): _a(0), _b(0){}; void incrementA(){++_a;}; void incrementB(){++_b;}; void logParam1(src::logger& lg, trivial::severity_level lvl) { stringstream s; s << "A: " << _a << ", B:" << _b; BOOST_LOG_FUNCTION(); BOOST_LOG_SEV(lg, lvl) << s.str(); } void logParam2(trivial::severity_level lvl) { BOOST_LOG_FUNCTION(); stringstream s; s << "A: " << _a << ", B:" << _b; switch(lvl) { case trivial::trace: BOOST_LOG_TRIVIAL(trace) << s.str(); break; case trivial::debug: BOOST_LOG_TRIVIAL(debug) << s.str(); break; case trivial::warning: BOOST_LOG_TRIVIAL(warning) << s.str(); break; case trivial::info: BOOST_LOG_TRIVIAL(info) << s.str(); break; case trivial::error: BOOST_LOG_TRIVIAL(error) << s.str(); break; case trivial::fatal: BOOST_LOG_TRIVIAL(fatal) << s.str(); break; } } private: int _a; int _b; }; int main() { SensorOptions so; char* data[3]; int nparams = 3; char path[255]; memset(path, 0, 255); getcwd(path, 255); string cmd_line("./sensor -c "); cmd_line += path; cmd_line += "/data/ludmilla.conf"; istringstream iss(cmd_line); string token; int i = 0; while (getline(iss, token, ' ')) { if (i >= nparams) return 0; data[i] = new char[255]; if (!data[i]) return 0; memcpy(data[i], token.c_str(), token.size()); data[i][token.size()] = '\0'; ++i; } src::logger lg; if (!so.parse(nparams, data, stream_null)) std::cout << "Configuration parsing failed\n"; boost::any filename = so.loggingConfig["Sink:File"]["FileName"]; if (boost::any_cast<string>(&filename) == NULL) { std::cout << " Filename empty\n"; return 0; } std::cout << " Filename:" << *(boost::any_cast<string>(&filename)) << endl; init_from_settings(so.loggingConfig); std::cout<< "dopo init\n"; MyClass mc; mc.incrementA(); mc.incrementB(); mc.logParam1(lg, trivial::warning); mc.logParam2(trivial::warning); mc.incrementA(); mc.incrementB(); mc.logParam1(lg, trivial::info); mc.logParam2(trivial::info); return 1; } and that's the result of its running.

1 0

Matrix of external data
by petros 31 Mar '11

31 Mar '11

Hi, I am new to the matrix functionality of ublas and would like to ask a couple of questions. What I want to do is use the matrix data structures from ublas, together with a vendor supplied lapack (mkl). The issue is that , lapack acts on raw pointers to the matrix data, which, most of the time, it assumes to be contiguous – or some striding info is requested. Here are the questions: a) it is not clear to me that the storage is guaranteed to be contiguous. What would be the appropriate storage class to use? I would prefer that this is not stl-vector-based choice, since this is no longer guaranteed (to my knowledge) to possess this property. b) is there a way to wrap the data structure into a reference counted pointer? There would be a few benefits to this, as using the same matrix from different threads. Also, obviously, sharing the same data from many matrices, views to matrices etc. Also, very importantly to me, I would like to have the ability to “create” a matrix form an existing raw pointer, by “dressing” it into a ref-counted one, therefore separating the data ownership from the matrix functionality. Is there an example that does something along these lines? Thank you very much, in advance, for your help, Petros

3 5

boost link error
by shi zhijie 31 Mar '11

31 Mar '11

Hi,everyone: This is the first time for me to write a mail in english, so i may make some mistake,forgive me and thank you. I'm compiling our project on linux,and my environment is: os:fedora 12 compiler:gcc version 4.4.4 program language:c++ libraries:boost_1_46_1,log4cplus,librtmp,protobuf,libnat etc. I compile the project in static link mode,since the protobuf is just a static library(google recommended),and i don't down how to complie between a shared library and a static library. I konw boost::thread depend on pthread,so i let gcc to link pthread with -lpthread, but i still got the follow link error, the add-on files is all the makefile and a error report: g++ -o letvp2sp -g -O2 -W -Wall -D_DEBUG -std=c++0x -Wl,-rpath -static -I../include -I../P2SP -I../../log4cplus-1.0.4/include -L../../log4cplus-1.0.4/lib -L../Debug -llog4cplus -lp2sp -ldatamgr -lpthread -lrt -lboost_thread letvp2sp.cpp /tmp/cc4u6ZiF.o: In function `call_once<void (*)()>': /opt/boost/include/boost/thread/pthread/once.hpp:51: undefined reference to `boost::detail::get_once_per_thread_epoch()' /tmp/cc4u6ZiF.o: In function `pthread_mutex_scoped_lock': /opt/boost/include/boost/thread/pthread/pthread_mutex_scoped_lock.hpp:24: undefined reference to `boost::detail::once_epoch_mutex' /opt/boost/include/boost/thread/pthread/pthread_mutex_scoped_lock.hpp:26: undefined reference to `boost::detail::once_epoch_mutex' /opt/boost/include/boost/thread/pthread/pthread_mutex_scoped_lock.hpp:26: undefined reference to `pthread_mutex_lock' /tmp/cc4u6ZiF.o: In function `call_once<void (*)()>': /opt/boost/include/boost/thread/pthread/once.hpp:88: undefined reference to `boost::detail::once_global_epoch' /opt/boost/include/boost/thread/pthread/once.hpp:88: undefined reference to `boost::detail::once_global_epoch' /tmp/cc4u6ZiF.o: In function `checked_delete<PLAYERS::players_service>': /opt/boost/include/boost/checked_delete.hpp:34: undefined reference to `PLAYERS::players_service::~players_service()' /tmp/cc4u6ZiF.o: In function `call_once<void (*)()>': /opt/boost/include/boost/thread/pthread/once.hpp:84: undefined reference to `boost::detail::once_epoch_mutex' /opt/boost/include/boost/thread/pthread/once.hpp:84: undefined reference to `boost::detail::once_epoch_cv' /opt/boost/include/boost/thread/pthread/once.hpp:84: undefined reference to `pthread_cond_wait' /tmp/cc4u6ZiF.o: In function `pthread_mutex_scoped_unlock': /opt/boost/include/boost/thread/pthread/pthread_mutex_scoped_lock.hpp:51: undefined reference to `boost::detail::once_epoch_mutex' /opt/boost/include/boost/thread/pthread/pthread_mutex_scoped_lock.hpp:51: undefined reference to `pthread_mutex_unlock' /tmp/cc4u6ZiF.o: In function `Utility::Singleton<PLAYERS::players_service>::init()': /home/szj0306/letv_gl_p2sp/trunk/letvp2sp/../include/Singleton.h:24: undefined reference to `PLAYERS::players_service::players_service(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)' /tmp/cc4u6ZiF.o: In function `checked_delete<PLAYERS::players_service>': /opt/boost/include/boost/checked_delete.hpp:34: undefined reference to `PLAYERS::players_service::~players_service()' /tmp/cc4u6ZiF.o: In function `~pthread_mutex_scoped_unlock': /opt/boost/include/boost/thread/pthread/pthread_mutex_scoped_lock.hpp:55: undefined reference to `boost::detail::once_epoch_mutex' /opt/boost/include/boost/thread/pthread/pthread_mutex_scoped_lock.hpp:55: undefined reference to `pthread_mutex_lock' /tmp/cc4u6ZiF.o: In function `call_once<void (*)()>': /opt/boost/include/boost/thread/pthread/once.hpp:77: undefined reference to `boost::detail::once_global_epoch' /opt/boost/include/boost/thread/pthread/once.hpp:77: undefined reference to `boost::detail::once_global_epoch' /opt/boost/include/boost/thread/pthread/once.hpp:78: undefined reference to `boost::detail::once_epoch_cv' /opt/boost/include/boost/thread/pthread/once.hpp:77: undefined reference to `boost::detail::once_global_epoch' /opt/boost/include/boost/thread/pthread/once.hpp:77: undefined reference to `boost::detail::once_global_epoch' /opt/boost/include/boost/thread/pthread/once.hpp:78: undefined reference to `pthread_cond_broadcast' /tmp/cc4u6ZiF.o: In function `~pthread_mutex_scoped_unlock': /opt/boost/include/boost/thread/pthread/pthread_mutex_scoped_lock.hpp:55: undefined reference to `boost::detail::once_epoch_mutex' /opt/boost/include/boost/thread/pthread/pthread_mutex_scoped_lock.hpp:55: undefined reference to `pthread_mutex_lock' /tmp/cc4u6ZiF.o: In function `call_once<void (*)()>': /opt/boost/include/boost/thread/pthread/once.hpp:73: undefined reference to `boost::detail::once_epoch_cv' /opt/boost/include/boost/thread/pthread/once.hpp:73: undefined reference to `pthread_cond_broadcast' /tmp/cc4u6ZiF.o: In function `checked_delete<PLAYERS::players_service>': /opt/boost/include/boost/checked_delete.hpp:34: undefined reference to `PLAYERS::players_service::~players_service()' /tmp/cc4u6ZiF.o: In function `__static_initialization_and_destruction_0': /opt/boost/include/boost/system/error_code.hpp:214: undefined reference to `boost::system::generic_category()' /opt/boost/include/boost/system/error_code.hpp:215: undefined reference to `boost::system::generic_category()' /opt/boost/include/boost/system/error_code.hpp:216: undefined reference to `boost::system::system_category()' /tmp/cc4u6ZiF.o: In function `get_system_category': /opt/boost/include/boost/asio/error.hpp:220: undefined reference to `boost::system::system_category()' /tmp/cc4u6ZiF.o: In function `posix_tss_ptr_create': /opt/boost/include/boost/asio/detail/impl/posix_tss_ptr.ipp:34: undefined reference to `pthread_key_create' /tmp/cc4u6ZiF.o: In function `get_system_category': /opt/boost/include/boost/asio/error.hpp:220: undefined reference to `boost::system::system_category()' /tmp/cc4u6ZiF.o: In function `checked_delete<PLAYERS::players_service>': /opt/boost/include/boost/checked_delete.hpp:34: undefined reference to `PLAYERS::players_service::~players_service()' /tmp/cc4u6ZiF.o: In function `~posix_tss_ptr': /opt/boost/include/boost/asio/detail/posix_tss_ptr.hpp:48: undefined reference to `pthread_key_delete' /tmp/cc4u6ZiF.o: In function `boost::pthread::pthread_mutex_scoped_lock::unlock()': /opt/boost/include/boost/thread/pthread/pthread_mutex_scoped_lock.hpp:30: undefined reference to `pthread_mutex_unlock' /tmp/cc4u6ZiF.o: In function `Utility::Singleton<PLAYERS::players_service>::init()': /home/szj0306/letv_gl_p2sp/trunk/letvp2sp/../include/Singleton.h:24: undefined reference to `PLAYERS::players_service::players_service(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)' /tmp/cc4u6ZiF.o: In function `checked_delete<PLAYERS::players_service>': /opt/boost/include/boost/checked_delete.hpp:34: undefined reference to `PLAYERS::players_service::~players_service()' /usr/lib/gcc/i686-redhat-linux/4.4.4/libstdc++.a(locale.o): In function `std::locale::_Impl::_M_install_cache(std::locale::facet const*, unsigned int)': (.text._ZNSt6locale5_Impl16_M_install_cacheEPKNS_5facetEj+0x3f): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libstdc++.a(locale.o): In function `std::locale::_Impl::_M_install_cache(std::locale::facet const*, unsigned int)': (.text._ZNSt6locale5_Impl16_M_install_cacheEPKNS_5facetEj+0x77): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libstdc++.a(locale.o): In function `std::locale::_Impl::_M_install_cache(std::locale::facet const*, unsigned int)': (.text._ZNSt6locale5_Impl16_M_install_cacheEPKNS_5facetEj+0x197): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libstdc++.a(locale_init.o): In function `std::locale::locale()': (.text._ZNSt6localeC2Ev+0x2b): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libstdc++.a(locale_init.o): In function `std::locale::locale()': (.text._ZNSt6localeC2Ev+0x47): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libstdc++.a(locale_init.o): In function `std::locale::global(std::locale const&)': (.text._ZNSt6locale6globalERKS_+0x27): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libstdc++.a(locale_init.o): In function `std::locale::global(std::locale const&)': (.text._ZNSt6locale6globalERKS_+0x8e): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libstdc++.a(locale_init.o): In function `std::locale::global(std::locale const&)': (.text._ZNSt6locale6globalERKS_+0x19a): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libstdc++.a(eh_alloc.o): In function `__gnu_cxx::__scoped_lock::~__scoped_lock()': (.text._ZN9__gnu_cxx13__scoped_lockD2Ev[_ZN9__gnu_cxx13__scoped_lockD5Ev]+0x26): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libstdc++.a(eh_alloc.o): In function `__cxa_free_exception': (.text.__cxa_free_exception+0x69): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libstdc++.a(eh_alloc.o): In function `__cxa_free_exception': (.text.__cxa_free_exception+0x84): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libstdc++.a(eh_alloc.o): In function `__cxa_free_dependent_exception': (.text.__cxa_free_dependent_exception+0x6c): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libstdc++.a(eh_alloc.o): In function `__cxa_free_dependent_exception': (.text.__cxa_free_dependent_exception+0x87): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libstdc++.a(eh_alloc.o): In function `__cxa_allocate_exception': (.text.__cxa_allocate_exception+0xaf): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libstdc++.a(eh_alloc.o): In function `__cxa_allocate_exception': (.text.__cxa_allocate_exception+0x10f): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libstdc++.a(eh_alloc.o): In function `__cxa_allocate_dependent_exception': (.text.__cxa_allocate_dependent_exception+0x67): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libstdc++.a(eh_alloc.o): In function `__cxa_allocate_dependent_exception': (.text.__cxa_allocate_dependent_exception+0xb9): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libgcc_eh.a(unwind-dw2-fde-glibc.o): In function `__register_frame_info_bases': (.text+0x61): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libgcc_eh.a(unwind-dw2-fde-glibc.o): In function `__register_frame_info_bases': (.text+0x78): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libgcc_eh.a(unwind-dw2-fde-glibc.o): In function `__register_frame_info_table_bases': (.text+0x12b): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libgcc_eh.a(unwind-dw2-fde-glibc.o): In function `__register_frame_info_table_bases': (.text+0x142): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libgcc_eh.a(unwind-dw2-fde-glibc.o): In function `_Unwind_Find_FDE': (.text+0x187c): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libgcc_eh.a(unwind-dw2-fde-glibc.o): In function `_Unwind_Find_FDE': (.text+0x18ca): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libgcc_eh.a(unwind-dw2-fde-glibc.o): In function `__deregister_frame_info_bases': (.text+0x1a72): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i686-redhat-linux/4.4.4/libgcc_eh.a(unwind-dw2-fde-glibc.o): In function `__deregister_frame_info_bases': (.text+0x1af4): undefined reference to `pthread_mutex_unlock' collect2: ld returned 1 exit status make: *** [letvp2sp] Error 1 It troubled me for a few days.I'm puzzling.........

1 0

Issues with boost::process from the sandbox and the boost::process::child semantics
by Jan Kundrát 31 Mar '11

31 Mar '11

Hi folks, this is my first post to this list, so I hope I'll include enough information to make it useful. I'd like to write a class with the following interface: class Process { public: Process(const std::vector<std::string> &args); std::string readEverythingReceivedSoFar(); void write(const std::string &data); private: something childProcess; }; and when looking for building blocks to use, I came across the process library in boost's sandbox [1]. On a first sight, it looks great and implements much more than what I need now, and has a nice documentation -- so far so good. But when I actually tried to use it, I wasn't able to get it working without resorting to something which is an ugly hack to me. It's obvious that I have to have some access to "the child process" from the reading/writing methods, and -- because I don't like leaving zombie processes behind me -- also from my destructor to be able to kill it. In this library, there's a boost::process::child which is intended to be used for exactly this purpose, so I tried to add that as that "something" member. For technical reasons (got to do some postprocessing to the user-supplied arguments before I actually launch my process), I can't initialize the childProcess in the initializer list before the actual constructor body, which means that the compiler will have to initialize it to something for me. It turns out that the boost::process::child class is missing a default constructor, so my member can't be of that type (unless I wanted to create a very artificial instance with a faked PID, fabricated FDs etc). So I had to use pointers for that, which is IMHO bad because it needs dynamic memory allocation without a real reason. I realize that we're talking about a fork() here, so a dynamic memory allocation is not a problem from the performance point of view, but I prefer not to use it unless I have to. The only solution I could come up is the following: private: std::tr1::shared_ptr<boost::process::child> childProcess; and in the constructor: childProcess.reset(new boost::process::child(boost::process::launch(exe, arguments, ctx))); ...because I get a boost::process::child by value, so I have to invoke a copy constructor and put that object on the heap, if I understand this issue correctly. That smells fishy. So, I'd highly appreciate if you could tell me whether my understanding is correct, and if there's a better way out of here. In case I missed something obvious, I'd be very happy to learn about that, too. With kind regards, Jan [1] `svn co http://svn.boost.org/svn/boost/sandbox/process/` -- Trojita, a fast e-mail client -- http://trojita.flaska.net/

6 7

no exceptions
by Hochhaus, Andrew 30 Mar '11

30 Mar '11

Hi, I would like to use boost with BOOST_NO_EXCEPTIONS [1] and the g++ -fno-exceptions flag. However, it appears that some spots in boost library code: a) throw exceptions with the "raw" throw keyword [instead of BOOST_THROW_EXCEPTION or boost::throw_exception] b) use try ... catch blocks without "#ifnef BOOST_NO_EXCEPTIONS" guards This leaves me with the following questions. 1) Is BOOST_NO_EXCEPTIONS actively supported or a legacy construct? 2) What is the "recommended" way to throw exceptions inside boost library code (BOOST_THROW_EXCEPTION, boost::throw_exception, etc)? 3) If this is not intended behavior, would incremental patches to remove these dependencies be considered for inclusion? Thanks, Andy [1] http://www.boost.org/doc/libs/1_46_1/libs/exception/doc/throw_exception.html

3 5

[BGL] Question/suggestion about example/astar-cities.cpp
by Cedric Laczny 30 Mar '11

30 Mar '11

Hi, I had a look at the A*-search documentation and example code provided by boost (http://www.boost.org/doc/libs/1_46_1/libs/graph/doc/astar_search.html) In the example code, an exception is thrown as soon as the examined vertex is equal to the goal-vertex. Now I am wondering if this example is adequate because, as far as I have thought about it, this solution must not necessarily fullfill the characteristics of the A*-algorithm as it might lead to a premature abort (indeed actually intended) and thus could miss an optimal solution. Simple scenario: A graph with 3 vertices: one start, one goal, one intermediate and 3 edges: (start, goal), (start, intermediate), (intermediate, goal). If the weights are "similar enough" and the heuristic might be beneficial for the direct edge (start, goal), the program will throw the error when it examines the goal vertex, while actually it might have been optimal to take the route over the intermediate-vertex. This is not intended to be picky. I just sat on the example (or a custom modification to it) for quite some time now, wondering if my thoughts are correct. If they are, I think a short comment/note might help to clarify the situation for future readers, perhaps getting unexpected results on their own. Please correct me if I missed some point there. Thank you. Best, Cedric

3 3

vs 2010 can't find correct boost lib version?
by Li, Tieniu 30 Mar '11

30 Mar '11

I built boost with visual studio 2010. Libraries of *-vc100-* are generated correctly. When trying to using boost.thread, VS 2010 generated error message: can't find *-vc90-*.lib. Any idea and fixing? Thanks a lot.

4 4

[boost-users] Boost.Parameter: ArgumentPack - is type contained
by Christoph Heindl 30 Mar '11

30 Mar '11

Hi, I'm trying to test an ArgumentPack for containment of a certain parameter. Since an ArgumentPack is a valid MPL Sequence, I think boost::mpl::contains should do the trick, but I fail to specify the correct type. Consider the following BOOST_PARAMETER_NAME(color); template<class Opts> void function_with_opts(const Opts &opts) { boost::mpl::contains<Opts, /* what type goes here if I'd like to test if color is present in Opts ? */ > )); } Best regards, Christoph

2 2

Re: [Boost-users] Fwd: [context review] Review starts today, Mars 21st 2011
by Nat Linden 30 Mar '11

30 Mar '11

On Wed, Mar 30, 2011 at 1:13 PM, Vicente BOTET <vicente.botet(a)wanadoo.fr> wrote: > I've checked my mail and I didn't received your mail > > From: Nat Linden <[hidden email]> > Date: Tue, Mar 22, 2011 at 10:38 PM > To: Vicente BOTET <[hidden email]> > Cc: Oliver Kowalke <[hidden email]> > > Please, could you tell me to which address did you sent it? I sent it to the e-mail address from which (my mailer claims) your context-review-related mail originates: (hand-obfuscated) vicente dot botet atsign wanadoo dot fr

1 0

Fwd: [context review] Review starts today, Mars 21st 2011
by Nat Linden 30 Mar '11

30 Mar '11

From: Vicente BOTET <vicente.botet(a)wanadoo.fr> Date: Tue, Mar 29, 2011 at 7:00 PM To: boost-users(a)lists.boost.org, boost(a)lists.boost.org > As Vladimir said you can post the review to the dev ML and follow up the > review using some archives as nabble boost dev for example. As a non-member, I cannot post to the dev mailing list: my mail was rejected. > If you are yet interested in making a review I will accept it on this ML > exceptionally as the review is almost finished. I will forward to the dev ML. > > Waiting for your review, > Vicente Thank you! I appreciate that. Eight days ago I sent my review to you and to Oliver personally. Although Oliver did receive that and subsequent mail messages, the fact that you are still awaiting my review means that you did not. I must ask the Boost Review Wizards to reconsider the dev-list-only review policy. Since a non-member can't post to the dev list and I can't reach the Review Manager with personal mail, apparently I have only two options: - post to boost-users and hope for the best - hop on and off the dev list every time I want to interject a comment. Frankly that doesn't scale well. I append my review and subsequent conversation with Oliver. Disinterested parties can stop here. Forwarded conversation Subject: [Boost-users] [context review] Review starts today, Mars 21st 2011 ------------------------ ---------- From: Nat Linden <nat(a)lindenlab.com> Date: Tue, Mar 22, 2011 at 10:38 PM To: Vicente BOTET <vicente.botet(a)wanadoo.fr> Cc: Oliver Kowalke <oliver.kowalke(a)gmx.de> On Sun, Mar 20, 2011 at 8:18 PM, Vicente BOTET <vicente.botet(a)wanadoo.fr> wrote: > The review of Oliver Kowalke Context library starts today Mars 21st 2011, and will end on Mars 30th. > > Boost.Context is a basic building block library that is used for more higher abstractions. It is used by Boost.Fiber, Boost.Tasklet and Boost.Task from the same author. I see that Boost.Fiber is on the review queue, but Boost.Tasklet and Boost.Task are not yet? > About the library: > > Boost.Context provides a possibility to switch between different user-level context and is intended to be the basis for a higher abstraction like coroutine and fiber. Thumbs up on introducing a separate library at the Context level of abstraction. YES, I think the library should be accepted into Boost. > Boost.Context allows to select the mechanism provided by the operating system (ucontext on UNIX, Windows Fibers on Windows) or a faster implementation provided by this library (fcontext using assembler). Note on the alternative implementation: I am not enthused about the idea of embedding the fcontext decision in source code. I would rather make that decision externally in the build machinery. > --------------------------------------------------- > > Please always state in your review, whether you think the library should be > accepted as a Boost library! > > Additionally please consider giving feedback on the following general > topics: > > - What is your evaluation of the design? It seems adequate, a thin wrapper around the underlying implementations. Nonetheless I'm going to suggest a few possible enhancements. void (fn)(void*) and void* vp are very classic-C. While I'm sure there are those who prefer to work at that level, I'd also want overloads supporting a templatized nullary callable, like Fiber, plus the args-for-implicit-bind variant. Hopefully Fiber and other high-level abstractions implemented on Context could simply leverage Context's support rather than reimplementing it. Since every library built on top of Context will want to support those constructs, if that support can be centralized in Context, it should be. One tiny quibble about the order of the parameters in the existing context() constructor supporting 'context const& nxt': I think of the function pointer fn and its data pointer vp as a logical pair. It seems odd to me that the 'nxt' parameter is inserted here: context(void (fn)(void*), context const& nxt, void* vp, stack_type && stack); instead of here: context(void (fn)(void*), void* vp, stack_type && stack, context const& nxt); especially considering that 'nxt' controls what happens when 'fn' is done. I'm not sure I understand the usefulness of a context object not currently associated with a stack object, but I realize that corresponds with a state designed into the underlying machinery, e.g. ucontext.h. Oh: the initial current context doesn't manage an explicit stack. Maybe a base class that represents a context with implicit stack, and a subclass that represents a context with explicit stack? (Is the static variable that underlies boost::context::current() thread-local?) Fiber-local-storage on Windows: may I suggest a context-local<T> abstraction for this library, implemented as Fiber-local for the Windows Fibers implementation and thread-local elsewhere? Exceptions: "must not throw exceptions" may be too limiting. It's hard for a typical coder to guarantee that no underlying code will throw. Of course you could require that every fn passed to context's constructor must have an explicit outermost try/catch(...) -- but that's the sort of boilerplate that's easy to forget. context could provide a wrapper containing that try/catch(...). In fact, you could even use Boost.Exception to propagate any such exception to "somewhere else" -- perhaps a context user's policy decision? Then one such policy choice could be "I guarantee no underlying code will throw," for those anxious to avoid the overhead. Exception management may feel like a topic best left for a higher-level abstraction -- but I don't see how that could work. If the higher-level abstraction is implemented in terms of Context, and if Context flatly forbids exceptions, how could the higher layer support them? On the other hand, if it *is* reasonable for Context to defer exception support to a higher level, then the documentation should be revised to state the requirements for that support. But again -- since every library built on Context will want exception support, if it can be centralized in Context, it should be. Maybe there should actually be three layers: platform-dependent RawContext with the currently-proposed level of support, Context with platform-independent extensions as suggested above, then Fiber/Coroutine/Task/whatever above Context? What's the use of a stack object representing not-a-stack? Wouldn't the abstraction be simpler and more robust if every stack object is guaranteed to represent a valid stack? That would seem to simplify some of the semantics of Context as well. That said -- I'm a bit concerned that the documentation seems to imply that stacks always grow downwards. Are we really never going to encounter machines on which the opposite is true? Shouldn't the stack concept include some support for directionality? The stack concept is fairly dense. Would it make any sense to define an actual stack abstract base class? Because Context is template-based, an implementation can (and protected_stack should) avoid that base class -- but it could provide user stack implementations with a starting point. Thumbs up on providing protected_stack rather than a plain memory area. > - What is your evaluation of the implementation? I briefly looked over impl/context_ucontext.hpp, and it's pretty clear, more or less what I'd expect. I glanced into impl/context_fiber.hpp. I didn't review the rest of the implementation. Again, the need to account for a context object that isn't currently managing a stack feels like clutter. The Boost.Coroutines documentation contains a discussion of the possible unreliability of the GetCurrentFiber() == 0x1E00 trick, and the value of calling IsThreadAFiber() on systems that support it. I note some ambivalence in context_fiber.hpp about that. Why is the IsThreadAFiber() implementation commented out? > - What is your evaluation of the documentation? At first I was confused about the usefulness of release_stack(). Here's my guess: although Context documentation doesn't say, Fiber states: "When a fiber returns from its main function the fiber is said to be finished and can not be further resumed." By implication, you can't restart a context object that has finished, either. (Worth stating in Context documentation.) However, you may want to create another context object to perform the same work again, in which case it would make sense to reuse the same stack object. Is that more or less the rationale? Whether or not I've guessed right, I think we could use a bit more explanation about your intended use of release_stack(). The Boost.Coroutines documentation notes that you can save the cost of ConvertThreadToFiber() and ConvertFiberToThread() per round trip by explicitly calling ConvertThreadToFiber() beforehand. context_fiber.hpp is implemented the same way; presumably the same note could be useful. Or are you assuming that all cycle-conscious users will select the fcontext implementation instead of the Fiber implementation? The page describing the stack concept is a bit confusing: it doesn't use the term "concept," and it actually references class protected_stack. Please clarify that "stack" is a concept, whereas "protected_stack" is an implementation of that concept bundled with the Context library. There's a confusing phrase in the description of stack::address(): "Function void* address() must return the address where the stack begins to grow downwards (to lower addresses)" -- so far so good, with a nod to the note above about stack direction -- "and the stack must be moveable." This seems to say that the Context library might move the block of memory in which the processor allocates stack frames. But that would completely invalidate data residing in those stack frames! I *think* the phrase is intended to mean that any class implementing the stack concept (the object containing stack pointer and size) must be moveable. Either way, the intent should be expressed more clearly. What is that phrase doing attached to the description of stack::address(), anyway? > - What is your evaluation of the potential usefulness of the library? C++ should have had standard library support for user-space context-switching (coroutines, tasks, whatever) a decade or more ago. As a stepping stone to getting there, Context is enormously valuable. > - Did you try to use the library? With what compiler? Did you have any > problems? I hope to have time over the next few days to try using it. I thought I'd better send these comments, based only on reading the documentation and a bit of the code, in case I run out of time. > - How much effort did you put into your evaluation? A glance? A quick > reading? In-depth study? I read through all the bundled documentation, plus a bit of the code. > - Are you knowledgeable about the problem domain? Yes. I've been using the (Vault) Boost.Coroutines library in production code on Windows, Mac and Linux. Because Mac OS X 10.4 doesn't support ucontext.h, I hacked in an alternate underlying context-switching implementation for 10.4 based on the GNU Pth library. (Having the Boost.Context API around, even without a viable implementation yet, would have been useful for that work.) I intend to try replacing that Boost.Coroutines Pth implementation with a Context implementation. (Those who still care about OS X 10.4 could then provide a Context implementation based on Pth. However, I myself no longer care.) If Context is accepted into Boost, It strikes me that a version of Boost.Coroutines based on Context would be a useful evolutionary step in the Vault. ---------- From: Oliver Kowalke <oliver.kowalke(a)gmx.de> Date: Wed, Mar 23, 2011 at 4:07 AM To: Nat Linden <nat(a)lindenlab.com>, boost(a)lists.boost.org > I see that Boost.Fiber is on the review queue, but Boost.Tasklet and > Boost.Task are not yet? boost.tasklet will be renamed to boost.strand (see my git repo). because all of those lib require boost.context and hafe to be reqorked (except boost.fiber) the review wizards requested to remove boost.task from the review queue. If boost.context is accepted and in a final state I'll request a review for the other libs. > > Boost.Context allows to select the mechanism provided by the operating > system (ucontext on UNIX, Windows Fibers on Windows) or a faster > implementation provided by this library (fcontext using assembler). > > Note on the alternative implementation: I am not enthused about the > idea of embedding the fcontext decision in source code. I would rather > make that decision externally in the build machinery. I've pulished an alternative version of boost.context - the user can decide in its code which implemention should be used. > void (fn)(void*) and void* vp are very classic-C. While I'm sure there > are those who prefer to work at that level, I'd also want overloads > supporting a templatized nullary callable, like Fiber, plus the > args-for-implicit-bind variant. Hopefully Fiber and other high-level > abstractions implemented on Context could simply leverage Context's > support rather than reimplementing it. Since every library built on > top of Context will want to support those constructs, if that support > can be centralized in Context, it should be. Becuae most of the work is done ins assembler I'd like to keep the things simple as possible. Supporting templatized ctors + args-for-implicit-bind variant would make the assembler too much complicated and thus error prone (different C++ calling conventions on the platforms etc.). So I want to stuck with the C-style callback and track boost.context as a building block for other libs providing higher abstractions. > I'm not sure I understand the usefulness of a context object not > currently associated with a stack object, but I realize that > corresponds with a state designed into the underlying machinery, e.g. > ucontext.h. Oh: the initial current context doesn't manage an explicit > stack. Maybe a base class that represents a context with implicit > stack, and a subclass that represents a context with explicit stack? You have to differentiate between a context created to execute a new execution context (the ctor accepting funtion, stack etc.) which manages its own stack (passed as argument) and the context instance grapping the current execution context (default ctor) which collect the CPU state but does not manage the current stack because it its already managedd by the operating system (in the case of main()-function for instance) or by another context create by its ctor with protected_stack instance as argument. void main() { ... // ctx1 grapps the current CPU state // but does not manage a stack because the // current stack belongs to the operating system/process context ctx1; // ctx2 represent a new execution path executing my_fn() // it manages its own stack context ctx2( my_fn, 0, protected_stack( 65536) ); // now we jump from the curretn execution context ctx1 // to the new execution context ctx2 which will execute // function my_fn() ctx1.jump_to( ctx2); // we return from my_fn() == jumped out of execution context ctx2 // back to ctx1 ... } ctx1 pin-points (you could have mutliple) a specific point in the code/execution path. > (Is the static variable that underlies boost::context::current() > thread-local?) context has no static variables and no boost::context::current() (maybe you are using an old version?). > Fiber-local-storage on Windows: may I suggest a context-local<T> > abstraction for this library, implemented as Fiber-local for the > Windows Fibers implementation and thread-local elsewhere? hmm - this what I want to handle in libs with higher abstractions. So boost.context can be thin as possible. > Exceptions: "must not throw exceptions" may be too limiting. It's hard > for a typical coder to guarantee that no underlying code will throw. > Of course you could require that every fn passed to context's > constructor must have an explicit outermost try/catch(...) -- but > that's the sort of boilerplate that's easy to forget. context could > provide a wrapper containing that try/catch(...). In fact, you could > even use Boost.Exception to propagate any such exception to "somewhere > else" -- perhaps a context user's policy decision? Then one such > policy choice could be "I guarantee no underlying code will throw," > for those anxious to avoid the overhead. The function which is pased as first argument to the ctor of context must not throw. The reason is that it is passed to C-functions (== functions declared as extern "C") and throwing an exception through C-code results in undefined behaviour. > Exception management may feel like a topic best left for a > higher-level abstraction -- but I don't see how that could work. If > the higher-level abstraction is implemented in terms of Context, and > if Context flatly forbids exceptions, how could the higher layer > support them? Exception hamdling should be done by higher abstractions. For instance using packaged_task/future (as shown in boost.tasklet). > On the other hand, if it *is* reasonable for Context to defer > exception support to a higher level, then the documentation should be > revised to state the requirements for that support. I believe yes. > What's the use of a stack object representing not-a-stack? Wouldn't > the abstraction be simpler and more robust if every stack object is > guaranteed to represent a valid stack? That would seem to simplify > some of the semantics of Context as well. stack must support move-semantics -> a moved stack must be represented == not-a-stack. This is usefull for reducing memory allocation/deallocation for stacks. boost.tasklet reuses (== moves) stacks from a context which is finished and caches the stack. If a new context has to created in moves the recycled stack into the new context. That's trhre reason why stack must be move-able. > That said -- I'm a bit concerned that the documentation seems to imply > that stacks always grow downwards. Are we really never going to > encounter machines on which the opposite is true? Shouldn't the stack > concept include some support for directionality? On all platforms I've been working on the stack grows downwards. > The stack concept is fairly dense. Would it make any sense to define > an actual stack abstract base class? Because Context is > template-based, an implementation can (and protected_stack should) > avoid that base class -- but it could provide user stack > implementations with a starting point. because the stack is a template argument of context it represents an implicit interface - so no explicit interface like abstract_stack is required. The current solution doesn't require stakc to derive from a base class. > Thumbs up on providing protected_stack rather than a plain memory area. protected_stack appends a guard page at the end of the stack. This guard page issues sefault/access violation if you acces the address of that page. This is usefull if the size of the stack is too small. Ypou could use your own stack implementation without such a guard page. But if you excced the stack range you overwrite in the worst case the memory of your own application. > Again, the need to account for a context object that isn't currently > managing a stack feels like clutter. see above - pin-point of current execution path/context > The Boost.Coroutines documentation contains a discussion of the > possible unreliability of the GetCurrentFiber() == 0x1E00 trick, and > the value of calling IsThreadAFiber() on systems that support it. I > note some ambivalence in context_fiber.hpp about that. Why is the > IsThreadAFiber() implementation commented out? That is because of the fact that Windows XP + Sevice Pack 2/3 defines _WIN32_WINNT >= _WIN32_WINNT_VISTA but doesn't declare ::IsThreadAFiber(). I didn't found a way to detect XP + SP 2/3 beside of _WIN32_WINNT. > > - What is your evaluation of the documentation? > > At first I was confused about the usefulness of release_stack(). moves the stack out of the context instance for inspection or recycling > The Boost.Coroutines documentation notes that you can save the cost of > ConvertThreadToFiber() and ConvertFiberToThread() per round trip by > explicitly calling ConvertThreadToFiber() beforehand. > context_fiber.hpp is implemented the same way; presumably the same > note could be useful. Or are you assuming that all cycle-conscious > users will select the fcontext implementation instead of the Fiber > implementation? Holger Grund has some concerns regarding exception handling in the assembler implementation of fcontext on Windows. So I've dissabled it - maybe if I could fix it I'll make it available too. > There's a confusing phrase in the description of stack::address(): > "Function void* address() must return the address where the stack > begins to grow downwards (to lower addresses)" -- so far so good, with > a nod to the note above about stack direction -- "and the stack must > be moveable." see my comments above > This seems to say that the Context library might move the block of > memory in which the processor allocates stack frames. But that would > completely invalidate data residing in those stack frames! I *think* > the phrase is intended to mean that any class implementing the stack > concept (the object containing stack pointer and size) must be > moveable. Either way, the intent should be expressed more clearly. > What is that phrase doing attached to the description of > stack::address(), anyway? do refere to moving the stack out of a context? then this don for reusing that memory junk - otherwise the stack get deallocated. > I intend to try replacing that Boost.Coroutines Pth implementation > with a Context implementation. (Those who still care about OS X 10.4 > could then provide a Context implementation based on Pth. However, I > myself no longer care.) If Context is accepted into Boost, It strikes > me that a version of Boost.Coroutines based on Context would be a > useful evolutionary step in the Vault. I'm interessted in porting boost.context to MAC OS X (some first stepps in Jamfiles -> allow ucontext) - unforutnately I've no box running MAC OS X. I hope we can work together. best regards, Oliver -- ---------- From: Nat Linden <nat(a)lindenlab.com> Date: Wed, Mar 23, 2011 at 10:22 PM To: Oliver Kowalke <oliver.kowalke(a)gmx.de> Cc: boost(a)lists.boost.org, Vicente BOTET <vicente.botet(a)wanadoo.fr> On Wed, Mar 23, 2011 at 4:07 AM, Oliver Kowalke <oliver.kowalke(a)gmx.de> wrote: > I've published an alternative version of boost.context - the user can decide in its code which implementation should be used. I saw your mail about that, but I haven't actually compared its documentation with the review version's. Please give an example when it would be useful to have a mixture of context-switching implementations, selected in source code? Since I haven't thought of one myself, I'm not convinced it's a good idea. >> void (fn)(void*) and void* vp are very classic-C. While I'm sure there >> are those who prefer to work at that level, I'd also want overloads >> supporting a templatized nullary callable, like Fiber, plus the >> args-for-implicit-bind variant. Hopefully Fiber and other high-level >> abstractions implemented on Context could simply leverage Context's >> support rather than reimplementing it. Since every library built on >> top of Context will want to support those constructs, if that support >> can be centralized in Context, it should be. > > Because most of the work is done ins assembler I'd like to keep the things simple as possible. Supporting templatized ctors + args-for-implicit-bind variant would make the assembler too much complicated and thus error prone (different C++ calling conventions on the platforms etc.). > So I want to stuck with the C-style callback and track boost.context as a building block for other libs providing higher abstractions. I certainly wouldn't ask you to try to implement these higher-level features in assembler. But I don't see why the library couldn't add C++ header files providing such features wrapped around the (assembler or native) underlying functionality. We will want features such as templatized callables and exception support in every higher-level library built on top of Context. Must every such library provide its own redundant, inconsistent implementation? >> Maybe a base class that represents a context with implicit >> stack, and a subclass that represents a context with explicit stack? > > You have to differentiate between a context created to execute a new execution context (the ctor accepting function, stack etc.) which manages its own stack (passed as argument) and the context instance wrapping the current execution context (default ctor) which collect the CPU state but does not manage the current stack because it its already managed by the operating system (in the case of main()-function for instance) or by another context create by its ctor with protected_stack instance as argument. > > void main() > { > ... > // ctx1 grapps the current CPU state > // but does not manage a stack because the > // current stack belongs to the operating system/process > context ctx1; > > // ctx2 represent a new execution path executing my_fn() > // it manages its own stack > context ctx2( my_fn, 0, protected_stack( 65536) ); > ... > } > > ctx1 pin-points (you could have multiple) a specific point in the code/execution path. Fair enough. Here are two different objects initialized in different ways, containing different state. Maybe they should be different classes? They share some operations, but other operations are only valid on one of these object types. Maybe these should be base class and subclass? >> (Is the static variable that underlies boost::context::current() >> thread-local?) > > context has no static variables and no boost::context::current() (maybe you are using an old version?). I downloaded Context from the vault before the review began, so yes, I guess that reference to boost::context::current() is obsolete. My question about a static variable is based on a mistaken guess. I assumed that there would be a global pointer referencing the context object passed to the last successful jump_to() call: the context object running now. You're saying there is not. I believe I understand. >> Fiber-local-storage on Windows: may I suggest a context-local<T> >> abstraction for this library, implemented as Fiber-local for the >> Windows Fibers implementation and thread-local elsewhere? > > hmm - this what I want to handle in libs with higher abstractions. So boost.context can be thin as possible. Then I'd like to reiterate my suggestion that the library you're proposing is the bottom level of a three-level library stack: this one that implements "raw" functionality, a middle layer that implements higher-level concepts useful to every top-level library, and whichever top-level library suits the application. It bothers me to assume that every top-level library must redundantly implement these high-level features. In terms of packaging, though, I actually think the library we're calling Context should provide both lower layers. That's because of my belief that every library implemented on top of Context will want the high-level features. Put differently, I'm not sure how useful the bottom layer is without the middle layer. Either way, I agree that we want to be able to directly access the bottom layer. >> On the other hand, if it *is* reasonable for Context to defer >> exception support to a higher level, then the documentation should be >> revised to state the requirements for that support. > > I believe yes. Perhaps you're saying that the same wrapper machinery that handles a templated callable could provide an outermost try/catch(...). That wrapper, guaranteed not to throw a C++ exception, will be executed by the top-level function passed to Context. Again, every realistic consumer of Context will need this... >> What's the use of a stack object representing not-a-stack? > > stack must support move-semantics -> a moved stack must be represented == not-a-stack. > This is useful for reducing memory allocation/deallocation for stacks. > boost.tasklet reuses (== moves) stacks from a context which is finished and caches the stack. If a new context has to created in moves the recycled stack into the new context. That's the reason why stack must be move-able. Okay, there's a default-constructed stack object which manages no memory, a stack object managing a memory area which is potentially useful for a processor stack, and a stack object managing a memory area actually in use by a processor stack. I'm still unclear on the usefulness of the first kind, a default-constructed stack object. >> Shouldn't the stack >> concept include some support for directionality? > > On all platforms I've been working on the stack grows downwards. I'll defer to the community. If any Boost users are targeting machines with stacks that grow upwards, I'll let them request Context protected_stack support. >> Why is the >> IsThreadAFiber() implementation commented out? > > That is because of the fact that Windows XP + Sevice Pack 2/3 defines _WIN32_WINNT >= _WIN32_WINNT_VISTA but doesn't declare ::IsThreadAFiber(). > I didn't found a way to detect XP + SP 2/3 beside of _WIN32_WINNT. Understood, thanks. I'm rolling my eyes, but not at you. >> > - What is your evaluation of the documentation? > >> The Boost.Coroutines documentation notes that you can save the cost of >> ConvertThreadToFiber() and ConvertFiberToThread() per round trip by >> explicitly calling ConvertThreadToFiber() beforehand. >> context_fiber.hpp is implemented the same way; presumably the same >> note could be useful. Or are you assuming that all cycle-conscious >> users will select the fcontext implementation instead of the Fiber >> implementation? > > Holger Grund has some concerns regarding exception handling in the assembler implementation of fcontext on Windows. So I've disabled it - maybe if I could fix it I'll make it available too. Okay, so at present even cycle-conscious Windows users must use the Fiber implementation. Therefore it does seem worth documenting the fact that calling ConvertThreadToFiber() on the current thread before first entry to Context can save a couple implicit ConvertThreadToFiber() and ConvertFiberToThread() calls per round trip. >> I intend to try replacing that Boost.Coroutines Pth implementation >> with a Context implementation. > > I'm interested in porting boost.context to MAC OS X (some first steps in Jamfiles -> allow ucontext) - unfortunately I've no box running MAC OS X. I hope we can work together. Sure! As I said, unless one selects the 10.4u (or earlier) SDK, the ucontext.h implementation should work. I haven't yet tried to build the Context library; is the ucontext.h implementation header-only? ---------- From: Oliver Kowalke <oliver.kowalke(a)gmx.de> Date: Thu, Mar 24, 2011 at 3:06 AM To: Nat Linden <nat(a)lindenlab.com>, boost(a)lists.boost.org > On Wed, Mar 23, 2011 at 4:07 AM, Oliver Kowalke <oliver.kowalke(a)gmx.de> > wrote: > > > I've published an alternative version of boost.context - the user can > decide in its code which implementation should be used. I think I follow Vicentes suggestion - boost.context provides only one class (boost::context<>) which preferes fcontext(asm) implementation if available otherwise ucontext/fiber. I'll implement a test-app in order to check how this design influences UNIX signal handling (hopefully the impact will be only to require not to change the UNIX signal mask in context<>). > I certainly wouldn't ask you to try to implement these higher-level > features in assembler. But I don't see why the library couldn't add > C++ header files providing such features wrapped around the (assembler > or native) underlying functionality. It would require to do an additional allocation and it might be that the higher implementations can do it more efficient/better suitable for there purposes/not required by some higher libs. Otherwise those libs would pay for the additional memory allocaton even if it would not be required. > We will want features such as templatized callables and exception > support in every higher-level library built on top of Context. Must > every such library provide its own redundant, inconsistent > implementation? The higher libs can implement what they want and how they want. > Here are two different objects initialized in different ways, > containing different state. Maybe they should be different classes? I think they should not be different - both do the same (jumping to other context). The difference is only the one does and the other doesn't manage a stack - but bot represent an execution context. > Perhaps you're saying that the same wrapper machinery that handles a > templated callable could provide an outermost try/catch(...). That > wrapper, guaranteed not to throw a C++ exception, will be executed by > the top-level function passed to Context. > > Again, every realistic consumer of Context will need this... I can add an additional trampoline function which has a try/catch-all block and issues an assertion if an exception was thrown. But this adds an additional indirection! > Okay, there's a default-constructed stack object which manages no > memory, a stack object managing a memory area which is potentially > useful for a processor stack, and a stack object managing a memory > area actually in use by a processor stack. I'm still unclear on the > usefulness of the first kind, a default-constructed stack object. The first is required to be able to jump from any position in the code to the second kind of context (which starts a new execution context). > Sure! As I said, unless one selects the 10.4u (or earlier) SDK, the > ucontext.h implementation should work. I haven't yet tried to build > the Context library; is the ucontext.h implementation header-only? yes regards, Oliver -- ---------- From: Nat Linden <nat(a)lindenlab.com> Date: Thu, Mar 24, 2011 at 8:05 AM To: Oliver Kowalke <oliver.kowalke(a)gmx.de> Cc: Vicente BOTET <vicente.botet(a)wanadoo.fr> On Thu, Mar 24, 2011 at 3:06 AM, Oliver Kowalke <oliver.kowalke(a)gmx.de> wrote: >> I certainly wouldn't ask you to try to implement these higher-level >> features in assembler. But I don't see why the library couldn't add >> C++ header files providing such features wrapped around the (assembler >> or native) underlying functionality. > > It would require to do an additional allocation and it might be that the higher implementations can do it more efficient/better suitable for there purposes/not required by some higher libs. With a centralized implementation of high-level features, if someone figures out how to make it more efficient, every consumer benefits. > Otherwise those libs would pay for the additional memory allocation even if it would not be required. I disagree. You need only continue to support the classic-C-style (void (*function_ptr)(void*), void* data_ptr) pair as an alternative to the templatized callable, for example by a different constructor overload. If a consumer doesn't want to pay for extra allocation/indirection, that caller can use the (function_ptr, data_ptr) pair as you presently intend. But a consumer library that does want the high-level features can leverage your central implementation. Everybody wins. >> there's a default-constructed stack object which manages no >> memory, a stack object managing a memory area which is potentially >> useful for a processor stack, and a stack object managing a memory >> area actually in use by a processor stack. I'm still unclear on the >> usefulness of the first kind, a default-constructed stack object. > > The first is required to be able to jump from any position in the code to the second kind of context (which starts a new execution context). This confuses me. I do understand that a default-constructed *context* object is useful to be able to switch context from any place in the code. But I'm now asking about the usefulness of a default-constructed *stack* object. A default-constructed *context* object is not passed a stack object. If you're saying that a default-constructed context object must nonetheless store a default-constructed stack object... this starts to feel like an implementation detail leaking out into the API. (This might be another good reason to break out a context object base class that stores only processor state without also storing a stack object.) Let me suggest an alternative way to manage stacks. Consider a raw stack memory area which never moves. It is allocated and managed by a stack class which either successfully allocates the requested size, or throws. The stack class object, containing only a pointer and length and other small state, is moveable; but even when the stack object moves, the actual memory area used by the processor stack does not move. This would eliminate the need to track a "not-a-stack" state: every validly-constructed stack object is a valid stack. Internally, a context object can store a pointer to a stack object, possibly with std::auto_ptr for ownership transfer. I do not believe that the overhead of following a pointer would exceed the overhead of having to check for a valid stack object on every access. And as I've suggested, if you want to eliminate even that overhead, break out a context class that always stores a valid stack, with a separate context class that does not even have a stack data member. >> [For Mac OS X,] unless one selects the 10.4u (or earlier) SDK, the >> ucontext.h implementation should work. I haven't yet tried to build >> the Context library; is the ucontext.h implementation header-only? > > yes In that case, what further Context work is needed to support Mac OS X? If you're saying that you want to extend the fcontext implementation for OS X, I'm sorry, I don't know details of how the assembler implementation should differ on OS X. Perhaps you're confident in the existing assembly code, and you simply want Boost.Build help in running the assembler on Mac. Unfortunately (my guilty secret), I do not know Boost.Build. I tried using an earlier version some years ago, but it failed in ways I found utterly opaque; it was simpler to build Boost sources as part of my application project. ---------- From: Oliver Kowalke <oliver.kowalke(a)gmx.de> Date: Thu, Mar 24, 2011 at 8:36 AM To: Nat Linden <nat(a)lindenlab.com> Cc: boost(a)lists.boost.org > This confuses me. > > I do understand that a default-constructed *context* object is useful > to be able to switch context from any place in the code. > > But I'm now asking about the usefulness of a default-constructed > *stack* object. A default-constructed *context* object is not passed a > stack object. because og the move-semantics supported by the stack class an default constructed stack instance means not-a-stack. It doesn't allocates memory. > If you're saying that a default-constructed context object must > nonetheless store a default-constructed stack object... this starts to > feel like an implementation detail leaking out into the API. It is not leaking - all classes providing move-semantics are used in this ways. Please look into boost.thread - boost::thread has a default ctor -> constructs a boost::thread instance that refers to Not-a-Thread. > In that case, what further Context work is needed to support Mac OS X? assembler implementation/fcontext - the source code has already an assembler file for MAC OS X (x86-64/i386). I wasn't able to test the code because I haven't a MAC OS X installation. Oliver -- ---------- From: Nat Linden <nat(a)lindenlab.com> Date: Thu, Mar 24, 2011 at 11:31 AM To: Oliver Kowalke <oliver.kowalke(a)gmx.de> On Thu, Mar 24, 2011 at 8:36 AM, Oliver Kowalke <oliver.kowalke(a)gmx.de> wrote: >> what further Context work is needed to support Mac OS X? > > assembler implementation/fcontext - the source code has already an assembler file for MAC OS X (x86-64/i386). I wasn't able to test the code because I haven't a MAC OS X installation. Okay, I'll try building it on OS X 10.5 and running your tests. It may take a little while for me to be able to pay attention to it.

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[asio] multi-threaded io_service::run produce wrong result
by leiming 30 Mar '11

30 Mar '11

Hi, there. At first, sorry for my poor English. I'm a newbie to boost and nowadays I'm trying understand how to use boost::asio in multi-thread environment. I have written a program as below: (I do know it's of no use, I wrote it just for learning) ------------------------------------------------------------ #include <boost/asio.hpp> #include <boost/thread.hpp> #include <boost/bind.hpp> #include <iostream> using std::cout; using std::endl; using namespace boost; using namespace boost::asio; io_service ioserv; mutex m; volatile int c = 0; void add() { lock_guard<mutex> g(m); ++c; } int main() { thread t1(bind(&io_service::run, ref(ioserv))); thread t2(bind(&io_service::run, ref(ioserv))); for(int i = 0; i < 655360; ++i) ioserv.post(&add); t1.join(); t2.join(); cout << c << endl; return 0; } ------------------------------------------------------------ the expected output is 655360. but in fact, nearly everytime when I ran it it gave me a different result ranged from 1 to 655360. I have checked my code, it locks the variable "c" before changing it. and I did join the two threads before I printed the value of "c". If I put the "post loop" before any thread that runs io_service::run starts, it prints 655360 but it's not what I want to add all task before thread starts. I have tried to compile the code with msvc7.1/boost 1.43, msvc9/boost 1.43 and msvc10/boost 1.46, the result is the same. I could find that only one thread works most of the time via process explorer. I thought that it's because t1 and t2 ended while the main thread was posting "add". Then I tried adding "ioserv.run();" before "t1.join();" but it didn't work. And then, if I didn't use t1 and t2, only run "ioserv.run();" after the "for" loop, the result became 655360. What I guessed is that, t1 and t2 ended when the main thread continues to post task to t1 and t2, then these task were lost. Just guessing, the source code of asio is currently hard for me... Is there anything wrong in my program? Hope someone could help me. thanks in advance. the compile and run environment is: 1 core cpu, windows xp pro, boost 1.43, msvc 7.1 1 core cpu, windows xp pro, boost 1.43, msvc 9 2 cores cpu, windows 7 pro, boost 1.46, msvc 10 regards, Leiming

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Increase iostream zlib filter buffer size
by rajiv82 30 Mar '11

30 Mar '11

I am using boost serialization(binary_oarchive) with iostream zlib filter. It is working fine but its too slow(takes 10hrs). After debugging I could see the buffer size as 4KB. My data is about 600MB. How can I increase the size of buffer to say 10MB. I tried following options:- 1. passing buffer size in zlib_compressor. 2. Redefining BOOST_IOSTREAMS_DEFAULT_DEVICE_BUFFER_SIZE to 10485760 But none of above seems to work. Please guide. -- View this message in context: http://boost.2283326.n4.nabble.com/Increase-iostream-zlib-filter-buffer-siz… Sent from the Boost - Users mailing list archive at Nabble.com.

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[Filesystem V3] Directory iterator seems to be broken.
by Michael Kaes 30 Mar '11

30 Mar '11

Hi all, I have the following two programs. In filesystem V2: ----------------------------------- boost::filesystem::wpath local_path(L"\\\\?\\C:\\"); boost::filesystem::wdirectory_iterator directoryContent(local_path); const std::wstring name1 = directoryContent->path().filename(); std::wcout << "Name 1 == " << name1 << std::endl; ++directoryContent; const std::wstring name2 = directoryContent->path().filename(); std::wcout << "Name 2 == " << name2 << std::endl; ------------------------------------ In filesystem V3: ------------------------------------ boost::filesystem::path local_path(L"\\\\?\\C:\\"); boost::filesystem::directory_iterator directoryContent(local_path); const std::wstring name1 = directoryContent->path().filename().wstring(); std::wcout << "Name 1 == " << name1 << std::endl; ++directoryContent; const std::wstring name2 = directoryContent->path().filename().wstring(); std::wcout << "Name 2 == " << name2 << std::endl; --------------------------------------- The output of V2 for my machine is Name 1 == $Recycle.Bin Name 2 == 00120.mpls This is correct and what I would expect. The output for V3 is Name 1 == $Recycle.Bin Name 2 == C:00120.mpls Which is incorrect. The root path is not correctly removed. Is this a BUG in V3 or did something in the API changed that I have not seen yet? Regards, Michael

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How to skip a sub-directory with filesystem3::recursive_directory_iterator in case of exception?
by Tan, Tom (Shanghai) 30 Mar '11

30 Mar '11

I am iterating a mapped network drive under windows, K:\, under which are 3 sub directories A, B, C, where K:\B is only visible itself but cannot be iterated into due to group policy. With code below: boost::system::error_code ec; for (recursive_directory_iterator itr(root, ec), itr_end; itr!=itr_end; itr++) { ... } It throws in itr++ when itr->path() == "K:\B". I would like to skip going into k:\B and go on with K:\C, so I code like this: for (recursive_directory_iterator itr(root, ec), itr_end; itr!=itr_end; ) { ... ; itr.increment(ec); } It does not solve my problem, but introduces one more: itr will never equal to itr_end even though all item are iterated over, and this happens for any normal folder such as K:\A. thus never get's out of for loop until the internal vetor<directory_iterator>::operator+=() asserts. Again, I tried something like below. for (recursive_directory_iterator itr(root, ec), itr_end; itr!=itr_end; ) { ... ; itr.increment(ec); if(ec) itr.pop(); } This time itr.pop() assertion fails because "pop() on recursive_directory_iterator with level < 1" Anybody got some advice? Thanks.

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GSOC 2011
by Rafael González 30 Mar '11

30 Mar '11

Hello I would like to participate with Boost in GSOC 11. I have some ideas about arbitrary precision and a Monte Carlo simulation framework. I've already seen the time line and I know that applications begin today, so, should I prepare it right now or I we have time to discuss it with someone. Thanks

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