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

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

04 Jun '12

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

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

23 May '09

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

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

08 Sep '08

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

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

26 Jun '08

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

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

12 Aug '07

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

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

09 Aug '07

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

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

01 Aug '07

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

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

10 Jun '07

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

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read_graphviz question
by Jeffrey Holle 26 Apr '07

26 Apr '07

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

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

25 Mar '07

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

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

15 Mar '07

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

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

11 Mar '07

Hello, I'm trying to use the Boost Threads library to help me implement a background loading system for a game I'm writing. I want to enqueue load requests while the main game thread is running, and have a separate thread load the data and pass back the appropriate objects. Currently when I enqueue a new request, I notify a 'something to do' condition, which my loading thread waits on. The trouble is, when I notify it, the loader could be loading in the background, and has a lock on the mutex connected with the condition. Would anyone be able to offer me any advice on how to solve this? Many thanks, Peter P.S. Please find attached my current implementation. begin 666 loader.cpp M(VEN8VQU9&4@(FQO861E<BYH<' B#0H-"B-I;F-L=61E(#QB;V]S="]B:6YD M+FAP<#X-"@T*;&]A9&5R.CIL;V%D97(H*0T*.B!T:')E861?<VAO=6QD7V5X M:70H9F%L<V4I#0I[#0H)=&AR96%D+G)E<V5T*&YE=R!B;V]S=#HZ=&AR96%D M*&)O;W-T.CIB:6YD*"9L;V%D97(Z.G1H<F5A9%]P<F]C+"!T:&ES*2DI.PT* M?0T*#0IL;V%D97(Z.GYL;V%D97(H*0T*>PT*"2\O(%-I9VYA;"!T:&4@=&AR M96%D('1O(&5X:70N#0H)>PT*"0EB;V]S=#HZ;75T97(a)Z.G-C;W!E9%]L;V-K M(&QO8VLH;75T97(a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` ` end begin 666 loader.hpp M(VEF;F1E9B!,3T%$15)?2%!0#0HC9&5F:6YE($Q/041%4E](4% -"@T*(VEN M8VQU9&4@/'%U975E/@T*(VEN8VQU9&4@/&)O;W-T+W-H87)E9%]P='(N:'!P M/@T*(VEN8VQU9&4@/&)O;W-T+W1H<F5A9"]C;VYD:71I;VXN:'!P/@T*(VEN M8VQU9&4@/&)O;W-T+W1H<F5A9"]M=71E>"YH<' ^#0HC:6YC;'5D92 \8F]O M<W0O=&AR96%D+W1H<F5A9"YH<' ^#0H-"F-L87-S(&QO861E<B Z('!R:79A M=&4@8F]O<W0Z.FYO;F-O<'EA8FQE#0I[#0IP=6)L:6,Z#0H-"@EL;V%D97(H M*3L-"@EV:7)T=6%L('YL;V%D97(H*3L-"@T*<')I=F%T93H-"@T*"79O:60) M=&AR96%D7W!R;V,H*3L-"@T*"2\O($%C8V5S<VEB;&4@8GD@86YY('1H<F5A M9"X-"@EB;V]S=#HZ;75T97@)"6UU=&5X.PT*"6)O;W-T.CIC;VYD:71I;VX) M<V]M971H:6YG7W1O7V1O.PT*"6)O;VP)"0D)=&AR96%D7W-H;W5L9%]E>&ET M.PT*"7-T9#HZ<75E=64\:6YT/@D)<&5N9&EN9U]L;V%D<SL-"@T*"2\O($%C M8V5S<VEB;&4@8GD@=&AE(&UA:6X@=&AE860@;VYL>2X-"@EB;V]S=#HZ<VAA M<F5D7W!T<CQB;V]S=#HZ=&AR96%D/@ET:')E860[#0I].PT*#0HC96YD:68- !"@`` ` end

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Re: [Boost-users] Cannot build boost on MSVS8 per instructions
by DAVID CRAVEY 20 Feb '07

20 Feb '07

Hi All, I am having the same errors as in this post: http://lists.boost.org/boost-users/2006/09/22001.php I have tried downloading the boost-jam both binary: boost-jam-3.1.13-1-ntx86.zip (I get the same error as the above post) And from source: boost-jam-3.1.13.zip I get a "Debug Assertion Failed!" error when I run build.bat Program: C:\Boost\boost-jam-3.1.13\bootstrap\jam0.exe File: dtoxtm64.c Line: 67 Expression: ( ( ( long )( yr - 1990) >= BASE_YEAR) && ( ( long )( yr - 1990 ) <= _MAX_YEAR64 ) ) Running the prebuilt bjam.exe file in the Threads build directory (running from Visual Studio 2005 Command Prompt): C:\Boost\boost_1_33_1\libs\thread\build>bjam "-sTOOLS=vc-8_0" Built three library files. So I think the bjam.exe file probably is not corrupt. If I run (from Visual Studio 2005 Command Prompt): C:\Boost\boost_1_33_1>bjam "-sTOOLS=vc-8_0 --with-threads" I get the same 00012f2a error as before. Other Notes: I have Visual C++ 2003 Standard and Visual Studio 2005 Pro Installed. Starting with the appropriate command prompt, I get the same error on both at Offset 0001f2fa. My machine is an Dell Latitude Centrinio Running Windows XP Pro SP2. Any help would be greatly appreciated! Thanks, David Cravey

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[boost-users] [interprocess] Using semaphores to synchronize startup
by Lars Hagström 09 Feb '07

09 Feb '07

Hi, I am trying to use Boost.Interprocess to get N processes (senders) to send data to one receiver through shared memory. The receiver has to be the one that initializes the shared memory, so no senders can be "let in" before the receiver has completed initialization. I can't guarantee the order that the processes are starting in. To do this I have both the receiver and the senders create_or_open a named_semaphore with 0 as initial value. The senders then immediately do a wait on the semaphore, but the receiver goes ahead and initializes the memory and then does a post on the semaphore. This lets the first sender in, which can then initialize itself and then do a post on the semaphore and start running. The second sender is then let in (because of the post) and it can get going and so on. This approach works very well if the semaphore has been manually deleted from /dev/shm/ or c:\temp\boost_interprocess\, but will not work if there is an old semaphore around. I can get around this on Windows by doing a named_semaphore::remove, since that will fail if a process has got it loaded. But this same code will not work on linux, since the semaphore will be unlinked and then all the processes will be able to delete the semaphore and will then be using different semaphores! I am used to semaphores working so that if it is opened when noone has it loaded it will be initialized to some known value, but this does not appear to be the case with Boost.Interprocess semaphores? Is there something obvious that I've missed, or some other way of accomplishing the same thing? Cheers Lars

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[signals] Automatic connection management and MT
by Timmo Stange 07 Feb '07

07 Feb '07

I'm working on a preliminary solution for an interface-compatible but thread-safe implementation of Signals for my project so that I will be able to switch to Boost.Signals should Doug Gregor find the time to add thread-safety there. While deciding what parts to include and which to leave out, I noticed that the automatic connection management is probably not usable in a multi-threaded context in the current form. Using a base class destructor (signals::trackable) to monitor an observer's lifetime is bound to result in race condition trouble with the order of destruction in a class hierarchy. Has that been discussed somewhere and are there any proposed solutions/alternatives? Regards Timmo Stange

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Re: [Boost-users] [date_time] timezone rules for different years
by Stephen Turner 06 Feb '07

06 Feb '07

> -----Original Message----- > From: Stephen Turner [mailto:sturner@clicktracks.com] > Sent: 22 December 2006 16:39 > To: 'boost-users(a)lists.boost.org' > Subject: [date_time] timezone rules for different years > > For my application, I need to be able to get the local time > of any UTC time in the last five years in any location. > > As far as I can see, the date_time library doesn't provide > this. The documentation says that date_time_zonespec.csv is > "based on data found in the zoneinfo datebase", but whereas > the zoneinfo database contains historical information about > daylight saving time changes, date_time_zonespec.csv only > seems to allow you to specify a single rule for each > timezone. And I can't find another mechanism to do it. > > Am I missing something, or is this capability not present? > And if not, is there any plan to add it? Or a workaround? I > anticipate that this will become more of a problem when the > rules for the U.S. change by several weeks next year. > I'm not sure whether this one got lost in the holiday break, or whether there's nobody who's familiar with the internals of this library on this list, but let me try again. I've been trying to work out how to add the capability to have different timezone rules in different years to the library. It seems to me it's not too hard (although I'm nervous of making such a judgement in code I'm not familiar with). I think all that's needed is: 1) In class custom_time_zone, the rules should depend on y, rather than there just being one set of rules. 2) The date_time_zonespec.csv file would have to have extra columns for years a rule applied to. tz_db_base::parse_string would have to parse them, and instead of creating a new timezone for each line, add the rule to the appropriate timezone if it had already been seen once. Is there anything else that would need to be done? Actually, I think the hardest part would be populating the date_time_zonespec.csv file. Is there already a program to generate that file from the zoneinfo files, or was it done semi-by-hand? Thanks, -- Stephen Turner, Cambridge, UK http://homepage.ntlworld.com/adelie/stephen/ "The internet is a reflection of our society. If we do not like what we see, the problem is not to fix the mirror, we have to fix society." (Vint Cerf)

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FW: Linker errors when using regex Lib with MSVC8 and STLPort 5.1.0 and Boost 1_33_1
by Manish Mangal 06 Feb '07

06 Feb '07

Hi I have built the StlPort 5.1.0 shared dlls and boost 1_33_1 Shared dlls successfully. The Platform is MSVC8. I created a sample projeth with just on file with code: #include <boost/regex.hpp> bool testregex( const char* StringToMatch ) { return( boost::regex_match( StringToMatch, boost::regex("[A-Z]+") )); } int main (int argc, char *argv[]) { bool trial = testregex( "hello how r u ?"); return 1; } Compilation succeeds but I get two Linker errors (BOOST_DYN_LINK is defined) Main.obj : error LNK2001: unresolved external symbol "public: bool __thiscall boost::re_detail::perl_matcher<char const *,class stlp_std::allocator<struct boost::sub_match<char const *> >,struct boost::regex_traits<char,class boost::w32_regex_traits<char> > >::match(void)" (?match@?$perl_matcher@PBDV?$allocator@U?$sub_match@PBD@boost@@@stlp_std @@U?$regex_traits@DV?$w32_regex_traits@D@boost@@@boost@@@re_detail@boost @@QAE_NXZ) 1>Main.obj : error LNK2001: unresolved external symbol "public: __thiscall boost::re_detail::perl_matcher<char const *,class stlp_std::allocator<struct boost::sub_match<char const *> >,struct boost::regex_traits<char,class boost::w32_regex_traits<char> > >::perl_matcher<char const *,class stlp_std::allocator<struct boost::sub_match<char const *> >,struct boost::regex_traits<char,class boost::w32_regex_traits<char> > >(char const *,char const *,class boost::match_results<char const *,class stlp_std::allocator<struct boost::sub_match<char const *> > > &,class boost::basic_regex<char,struct boost::regex_traits<char,class boost::w32_regex_traits<char> > > const &,enum boost::regex_constants::_match_flags,char const *)" (??0?$perl_matcher@PBDV?$allocator@U?$sub_match@PBD@boost@@@stlp_std@@U? $regex_traits@DV?$w32_regex_traits@D@boost@@@boost@@@re_detail@boost@@QA E@PBD0AAV?$match_results@PBDV?$allocator@U?$sub_match@PBD@boost@@@stlp_s td@@@2@ABV?$basic_regex@DU?$regex_traits@DV?$w32_regex_traits@D@boost@@@ boost@@@2@W4_match_flags@regex_constants@2@0@Z) So it cannot find the constructor for perl_matcher and the declaration for regex_match. I found a similar post on Boost : http://www.nabble.com/-regex-Using-regex-in-x64-exe-with-VC-8.0-t2088061 .html#a5755051 The suggested solutions on this post are: 1) check for intermixing of x86 and x64 : I am on 32 bit platform.. so intermixing does not apply 2) add regex source code and compile ( using BOOST_REGEX_NO_LIB) : I get the errors for stdext namespace 1>C:\boost_1_33_1\boost/regex/v4/regex_workaround.hpp(145) : error C2653: 'stdext' : is not a class or namespace name 1> C:\boost_1_33_1\boost/regex/v4/regex_format.hpp(562) : see reference to function template instantiation 'OutputIterator boost::re_detail::copy<const charT*,OutputIterator>(InputIterator,InputIterator,OutputIterator)' being compiled 1> with 1> [ 1> OutputIterator=boost::re_detail::string_out_iterator<stlp_std::basic_str ing<wchar_t,stlp_std::char_traits<wchar_t>,stlp_std::allocator<wchar_t>> >, 1> charT=wchar_t, 1> InputIterator=const wchar_t * 1> ] 1> C:\boost_1_33_1\boost/regex/v4/match_results.hpp(160) : see reference to function template instantiation 'OutputIterator boost::re_detail::regex_format_imp<boost::re_detail::string_out_iterator <S>,const wchar_t*,stlp_std::allocator<_Tp>,_CharT,boost::re_detail::trivial_forma t_traits<charT>>(OutputIterator,const boost::match_results<BidiIterator> &,const charT *,const charT *,boost::regex_constants::match_flag_type,const traits &)' being compiled 1> with 1> [ 1> OutputIterator=boost::re_detail::string_out_iterator<stlp_std::basic_str ing<wchar_t,stlp_std::char_traits<wchar_t>,stlp_std::allocator<wchar_t>> >, 1> S=stlp_std::basic_string<wchar_t,stlp_std::char_traits<wchar_t>,stlp_std ::allocator<wchar_t>>, 1> _Tp=boost::sub_match<const wchar_t *>, 1> _CharT=wchar_t, 1> charT=wchar_t, 1> BidiIterator=const wchar_t *, 1> traits=boost::re_detail::trivial_format_traits<wchar_t> 1> ] 1> C:\boost_1_33_1\boost/regex/v4/match_results.hpp(156) : while compiling class template member function 'stlp_std::basic_string<_CharT,_Traits,_Alloc> boost::match_results<BidiIterator>::format(const stlp_std::basic_string<_CharT,_Traits,_Alloc> &,boost::regex_constants::match_flag_type) const' 1> with 1> [ 1> _CharT=wchar_t, 1> _Traits=stlp_std::char_traits<wchar_t>, 1> _Alloc=stlp_std::allocator<wchar_t>, 1> BidiIterator=const wchar_t * 1> ] 1> C:\boost_1_33_1\boost/regex/v4/instances.hpp(86) : see reference to class template instantiation 'boost::match_results<BidiIterator>' being compiled 1> with 1> [ 1> BidiIterator=const wchar_t * 1> ] 1>C:\boost_1_33_1\boost/regex/v4/regex_workaround.hpp(145) : error C3861: 'unchecked_copy': identifier not found Can anyone suggest a solution?? Thanks in advance Manish Mangal Software Engineer atlas(r) search Partner for Results 206-816-8349 // phone Manish.Mangal(a)AtlasSolutions.com <mailto:t-Matt.Koch@AtlasSolutions.com> // email www.AtlasSolutions.com <outbind://116-000000001368D4B5F8F6D0488191444C76FD7C9507008921F4CB773B0 545AAED425DEF553BC300003A3500100000DB0C51F64BED3447AA6EC585072C4EC300000 1E3B7A70000/jenniferh/Local%20Settings/Temporary%20Internet%20Files/OLK3 /www.AtlasSolutions.com> // web

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[boost::serialization] Howto store derived classes through pointer to base - with templates and own archive?
by Marc Wäckerlin 05 Feb '07

05 Feb '07

Hi I have the following problem: My class structure is somehow like that: class A; // is pure virtual template <int NUM, typename ENUM> class B: public A; [...] I use my BinaryWrite archive class, as specified in thread: "[boost::serialization] Binary Stream with noAdditional Info: Here's the solution! [Howto derieve ownserialization archive?]" Now, when I try to stream a std::vector < boost::shared_ptr < A > > then I see in the function-trace log, that my writer has been called for the parent type A, but not for the derived types (B, C, ...). After this, I read again the "Except for one special case" part in the Archive Class Reference manual. After this, I added the following code in front of my archive type: ==================================================================== namespace image { class BinaryWriter; class BinaryReader; } #define BOOST_ARCHIVE_CUSTOM_OARCHIVE_TYPES ::image::BinaryWriter #define BOOST_ARCHIVE_CUSTOM_IARCHIVE_TYPES ::image::BinaryReader #include <boost/archive/detail/iserializer.hpp> #include <boost/archive/detail/oserializer.hpp> #include <boost/archive/detail/common_iarchive.hpp> #include <boost/archive/detail/common_oarchive.hpp> #include <boost/serialization/export.hpp> ==================================================================== But it still does not step into the correct child. After some more reading, I guess, that I'd have to use BOOST_CLASS_EXPORT(B), but that does not compile, because B is a template class. What's wrong, what's missing, what do I have to do? Thank you Regards Marc

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boost::interprocess::node_allocator problem (VC8, release build)
by alexmark 02 Feb '07

02 Feb '07

I have a problem with node_allocator. The "repro" code: #include <boost/interprocess/managed_external_buffer.hpp> #include <boost/interprocess/allocators/node_allocator.hpp> #include <boost/interprocess/containers/list.hpp> //////////////// using namespace boost::interprocess; //////////////// enum { A_SHARED_MEMORY_SIZE = 4096 * 50, A_POOL_SIZE = 512, }; //////////////// static char g_static_buffer[A_SHARED_MEMORY_SIZE]; static managed_external_buffer g_sharm (create_only, g_static_buffer, A_SHARED_MEMORY_SIZE); //////////////// typedef node_allocator<int, A_POOL_SIZE, managed_external_buffer::segment_manager> int_allocator_t; typedef list<int, int_allocator_t> IntList; //////////////// struct T { IntList int_list; // T () : int_list (int_allocator_t(g_sharm.get_segment_manager())) {} }; typedef node_allocator<T, A_POOL_SIZE, managed_external_buffer::segment_manager> tis_allocator_t; typedef list<T, tis_allocator_t> TList; //////////////// int main() { TList* p = g_sharm.construct<TList>(anonymous_instance)(tis_allocator_t(g_sharm.get_segment_manager())); try { enum { N = 2 }; // Create objects then delete them for (int n = 0; n < N; n++) { // Create T-type objects for (int i = 0; i < A_POOL_SIZE; i++) { p->push_back(T()); // push new object to the list } p->clear(); // Delete all T objects } } catch (bad_alloc &) { cout << "No memory" << endl; } g_sharm.destroy_ptr(p); return 0; } The problem is the folowing. If N > 1, on _second_ "pass" (n=1) the bad_alloc exception is thrown while pushing new T object to the list. Why? I supposed that on any "pass", except the first one, no new T-type objects are actually created in shared memory. They should be taken from the pool instead. I.e., if there's enough memory on the first "pass", it must be also enough on any other one. The problem is specific for Visual Studio 2005, when producing release build (all options carry their default values). Thanks, Alex.

3 6

problem with boost/iterator/zip_iterator.hpp
by Tim Axelrod 01 Feb '07

01 Feb '07

Hello, If more than one source file includes boost/iterator/zip_iterator.hpp, the loader complains about a multiply defined function: tsa@mops2.lsstcorp.org:~/VW/TSA> g++ -o nothing nothingMain.cc nothing.cc /tmp/ccT5Bn0N.o: In function `boost::detail::tuple_impl_specific::tuple_equal(boost::tuples::null_type, boost::tuples::null_type)': nothing.cc:(.text+0x0): multiple definition of `boost::detail::tuple_impl_specific::tuple_equal(boost::tuples::null_type, boost::tuples::null_type)' /tmp/ccH8Z9eR.o:nothingMain.cc:(.text+0x0): first defined here collect2: ld returned 1 exit status I'm using boost_1_33_1. The source files are attached. Regards, Tim Axelrod

2 1

shmem map tutorial
by Jan Stetka 31 Jan '07

31 Jan '07

I've put together a tutorial on how to use interprocess map. Its at http://myweb.tiscali.co.uk/janstetka/interprocess_map.html Perhaps there could be a link from the interprocesses documentation if it goes down well. Thanks PS:I tried to use the wiki but the syntax is a bit too difficult for me especially formating code so I've put it on my own site for now.

1 0

matrix inversion
by Umut Tabak 31 Jan '07

31 Jan '07

hi list, I have been experimenting to find the incerse aof a matrix with ublas but there is a problem: I have been looking at the code on http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl?LU_Matrix_In… But there is sth wrong with that code because assign function template does not take a ublas::matrix<> as a direct parameter, it should ne converted to a matrix_expression but how may I do that. I did the inversion by using the assignment operator but wondered how it could be done thorough assign function template. The code on the viki works if you change the line with the assign to inverse=ublas::identity_matrix<T>(A.size1()); Maybe it can be of help. My best,

1 0

Re: [Boost-users] problems with serialization library
by mauro gargano 31 Jan '07

31 Jan '07

thanks a lot Mark Wyszomierski!

1 0

Question about using Boost::for_each function to set a local variable if a condition is met
by Meryl Silverburgh 31 Jan '07

31 Jan '07

Hi, I am trying to Boost::for_each function to set a local variable if all elements in this is DEFAULT type. Here is my code, but I don't know how to implement the last part of the if_then call. boolean rtnValue = false; for_each(mylist.begin(), mylist.end(), if_then( bind(&ListItem::getType, _1) == DEFAULT, set the local value to true if true if all of them are DEFAULT type )); if you can give me some pointers, I will be appreciated. Thank you.

3 3

Open file name starting with "." in boost::filesystem
by Peng Yu 31 Jan '07

31 Jan '07

Hi, The following program gives some error. Can somebody let me know if it is possible to open filenames starting with "."? Thanks, Peng int main() { boost::filesystem::ofstream file(".abc"); } $ ./main-g.exe terminate called after throwing an instance of 'boost::filesystem::filesystem_error' what(): boost::filesystem::path: invalid name ".abc" in path: ".abc" Aborted

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