December 2011 - Boost-users - lists.preview.boost.org

[phoenix] ambiguity between std::begin/end and phoenix::begin/end due to ADL
by Nathan Ridge 04 Jan '12

04 Jan '12

Hello, I am running into a problem where an unqualified call to begin() on a range type whose template parameters include a Boost.Phoenix type (for examle filtered_range<Pred, R> where Pred is a phoenix function) is ambiguous because, in addition to the intended std::begin, phoenix::begin is being found by ADL. What can be done about this? There exists precedent for placing boost::xxx::begin/end functions in ADL barrier namespaces because C++11 encourages unqualified calls to begin/end (specifically, this was done for boost::range::begin/end). Should the same thing be done for Phoenix? Here is a minimal example that reproduces the problem: #include <iterator> #include <boost/range/adaptor/filtered.hpp> #include <boost/phoenix/phoenix.hpp> using std::begin; int main() { using boost::phoenix::arg_names::arg1; using boost::adaptors::filtered; int v[5]; const auto& f = v | filtered(arg1 < 0); begin(f); } And here are the errors, with GCC 4.7: test.cpp: In function 'int main()': test.cpp:15:12: error: call of overloaded 'begin( const boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less , boost::proto::argsns_::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal , boost::proto::argsns_::term< boost::phoenix::argument<1> >, 0l > >, boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal , boost::proto::argsns_::term<int>, 0l > > >, 2l > >, int [5] > & )' is ambiguous test.cpp:15:12: candidates are: In file included from string:53:0, from c++/4.7.0/bits/locale_classes.h:42, from ios_base.h:43, [STL Decryptor: Suppressed 3 more STL standard header messages] from test.cpp:1: c++/4.7.0/bits/range_access.h:58:5: decltype ( __cont.begin() ) begin( const boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost::proto::argsns_ ::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term< boost::phoenix::argument<1> >, 0l> >, boost ::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term<int>, 0l> > >, 2l> >, int [5]>; decltype (__cont.begin()) = boost::filter_iterator< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost::proto::argsns_ ::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term< boost::phoenix::argument<1> >, 0l> >, boost ::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term<int>, 0l> > >, 2l> >, int *> &) c++/4.7.0/bits/range_access.h:48:5: decltype ( __cont.begin() ) begin( const boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost::proto::argsns_ ::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term< boost::phoenix::argument<1> >, 0l> >, boost ::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term<int>, 0l> > >, 2l> >, int [5]>; decltype (__cont.begin()) = boost::filter_iterator< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost::proto::argsns_ ::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term< boost::phoenix::argument<1> >, 0l> >, boost ::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term<int>, 0l> > >, 2l> >, int *> &) In file included from boost/boost/phoenix/stl/container.hpp:11:0, from boost/boost/phoenix/stl.hpp:16, from boost/boost/phoenix/phoenix.hpp:18, from test.cpp:4: boost/boost/phoenix/stl/container/container.hpp:794:1: const boost ::phoenix::detail::expression::function_eval< boost::phoenix::stl::begin, boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost::proto::argsns_ ::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term< boost::phoenix::argument<1> >, 0l> >, boost ::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term<int>, 0l> > >, 2l> >, int [5]>; boost::phoenix::detail::expression::function_eval< boost::phoenix::stl::begin, A0>::type = boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::phoenix::detail::tag::function_eval, boost::proto ::argsns_::list2< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost::proto ::argsns_::term<boost::phoenix::stl::begin>, 0l>, boost ::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost::proto ::argsns_::term< boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost ::proto::argsns_::list2< boost::phoenix::actor< boost::proto::exprns_ ::basic_expr< boost::proto::tagns_::tag ::terminal, boost::proto ::argsns_::term< boost::phoenix ::argument<1> >, 0l> >, boost::phoenix::actor< boost::proto::exprns_ ::basic_expr< boost::proto::tagns_::tag ::terminal, boost::proto ::argsns_::term<int>, 0l> > >, 2l> >, int [5]> >, 0l> >, 2l> > >::type boost::phoenix::begin( const boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost::proto::argsns_ ::list2< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term< boost::phoenix::argument<1> >, 0l> >, boost ::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost ::proto::argsns_::term<int>, 0l> > >, 2l> >, int [5]>; boost::phoenix::detail::expression::function_eval< boost::phoenix::stl::begin, A0>::type = boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::phoenix::detail::tag::function_eval, boost::proto ::argsns_::list2< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost::proto ::argsns_::term<boost::phoenix::stl::begin>, 0l>, boost ::proto::exprns_::basic_expr< boost::proto::tagns_::tag::terminal, boost::proto ::argsns_::term< boost::range_detail::filtered_range< boost::phoenix::actor< boost::proto::exprns_::basic_expr< boost::proto::tagns_::tag::less, boost ::proto::argsns_::list2< boost::phoenix::actor< boost::proto::exprns_ ::basic_expr< boost::proto::tagns_::tag ::terminal, boost::proto ::argsns_::term< boost::phoenix ::argument<1> >, 0l> >, boost::phoenix::actor< boost::proto::exprns_ ::basic_expr< boost::proto::tagns_::tag ::terminal, boost::proto ::argsns_::term<int>, 0l> > >, 2l> >, int [5]> >, 0l> >, 2l> > &) Thanks, Nate

3 2

property type trait
by Amir Yazdanbakhsh 02 Jan '12

02 Jan '12

Hi, I new to boost graph library. The thing that I have in my mind is to find the type of property that passed to a function and execute something based on that. I implemented two bundled properties each for vertex and edge. I want to implement a general function, say print a property, if the passed property is a vertex property the function should iterate over vertices and print out them and if it's edge property it should iterate over edges. Is it any way to do that? Thanks Best Regards, A. Yazdanbakhsh >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> PhD. Student School of Electrical and Computer Engineering University of Wisconsin-Madison E-mail: yazdanbakhsh(a)wisc.edu <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

2 1

[multi_array]bug in strides calculation with some storage orderings
by Larry Evans 02 Jan '12

02 Jan '12

If I understand correctly, the multi_array storage order determines which strides are larger than others. In short: if( order[I]>order[I+1]) then stride[I]>stride[I+1] However, the output from the attached code shows that this is not always true. In the attached code, the mono_tonic_print function tests the conditions and prints out the results. The following partial output: :count=3 :permut_v={ 1, 2, 0} :permut_i={ 2, 0, 1} :ma.ordering(*)==permut_v=1 :multi_array_strides:strides()={ 12, 1, 3} :monotonically increasing={ 0, 0} :is_mono_tonic=0 :expected_strides:{ 4, 8, 1} :monotonically increasing={ 1, 1} :is_mono_tonic=1 :count=4 :permut_v={ 2, 0, 1} :permut_i={ 1, 2, 0} :ma.ordering(*)==permut_v=1 :multi_array_strides:strides()={ 4, 8, 1} :monotonically increasing={ 0, 0} :is_mono_tonic=0 :expected_strides:{ 12, 1, 3} :monotonically increasing={ 1, 1} :is_mono_tonic=1 shows that the multi_array code fails this monotonic constrait when the order is one of: :permut_v={ 1, 2, 0} :permut_v={ 2, 0, 1} The code also shows a possible solution. This possible solution uses the inverse permutation instead of the original permutation to calculate the strides, as shown in the expected_strides function. There's also a macro, NO_INVERT_PERMUT, which, if defined, has expected_strides reproduce the multi_array strides, which may help narrow down the source of the error in multi_array's stride calculation. The output is also attached. If macro INDENT_OUTPUT is defined, the code requires: http://svn.boost.org/svn/boost/sandbox/variadic_templates/boost/iostreams/f… http://svn.boost.org/svn/boost/sandbox/variadic_templates/boost/iostreams/u… http://svn.boost.org/svn/boost/sandbox/variadic_templates/boost/utility/tra… http://svn.boost.org/svn/boost/sandbox/variadic_templates/boost/utility/ind… If you don't want to download those, then the output will not be nicely indented as shown in the attached output. HTH. -regards, Larry

1 1

iterate over vertices with special propoerty
by Amir Yazdanbakhsh 01 Jan '12

01 Jan '12

Hi, I want to write an iterator which returns the vertices with a special property. For example have an functions which takes a graph and a string and returns an iterator over all the vertices that have this string as their name. Thanks Best Regards, A. Yazdanbakhsh >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> PhD. Student School of Electrical and Computer Engineering University of Wisconsin-Madison E-mail: yazdanbakhsh(a)wisc.edu <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

2 1

[inteprocess] timed_lock absolute time
by Edward Diener 01 Jan '12

01 Jan '12

Is the "absolute time" mentioned when using a mutex and timed_lock a local time or a UTC time ? I am guessing a local time but I just want to make sure.

2 5

Re: [Boost-users] Problem with Interpocess offset_ptr
by mike＠tesla.rcub.bg.ac.rs 30 Dec '11

30 Dec '11

Thank you Ion, it solved my problem. Qtree now works good and fast!

1 0

Build error on Solaris 10
by İhsan Doğan 30 Dec '11

30 Dec '11

Hi, I'm new to Boost and while trying to build it on Solaris 10 using the sun Toolset and the and Sun Studio 12.1 compiler I'm running into this issue: sun.archive bin.v2/libs/exception/build/sun/release/link-static/stdlib-sun-stlport/threading-multi/libboost_exception.a "CC" -xar -o "bin.v2/libs/exception/build/sun/release/link-static/stdlib-sun-stlport/threading-multi/libboost_exception.a" "bin.v2/libs/exception/build/sun/release/link-static/stdlib-sun-stlport/threading-multi/clone_current_exception_non_intrusive.o" common.copy stage/lib/libboost_exception.a cp "bin.v2/libs/exception/build/sun/release/link-static/stdlib-sun-stlport/threading-multi/libboost_exception.a" "stage/lib/libboost_exception.a" ...failed updating 4 targets... I'm kinda stuck here. What could be the reason for this error? Ihsan -- ihsan(a)dogan.ch http://blog.dogan.ch/

1 0

tcp error “more data is available”
by herzl&revital sham 29 Dec '11

29 Dec '11

I build a sync udp server via boost::asio follow bellow I bind to interface Socket.open(EndPoint.protocol()); Socket.set_option(boost::asio::ip::udp::socket::reuse_address(true)); Socket.bind(EndPoint); and read char mybuffer[1450]; Socket.async_receive_from( boost::asio::buffer(mybuffer, 1450), senderEndpoint_, boost::bind(&MsgReceiver::HandleReceive, this, boost::asio::placeholders::error, buffer, boost::asio::placeholders::bytes_transferred) ); then i send data to this server like below: yes "AAAAAAAAAAAAAAAAAaaAAAAAAA" | nc -u 172.16.0.12 1234 I get "more data is available" error message in HandleReceive and my system Crashes. I debugger this is all io_services status 0 > 5768 Worker Thread _threadstartex boost::asio::detail::win_iocp_io_service::work_finished Normal 0

1 0

boost::interprocess::string
by Josmon Paul 29 Dec '11

29 Dec '11

2 1

Problem with Interpocess offset_ptr
by mike＠tesla.rcub.bg.ac.rs 29 Dec '11

29 Dec '11

Hi, I need to store in the shared memory structure for Quadtree. It is a class with 4 pointers for tree regions and vector of points: class CNode4 { ... CNode4* node0; CNode4* node1; CNode4* node2; CNode4* node3; vector<vec2> pointArray; }; I have tried with class CNode4 { ... offset_ptr<CSNode4> node0; ... }; and using as: typedef allocator<void, managed_shared_memory::segment_manager> void_allocator; const void_allocator alloc_void(segment.get_segment_manager()); CSNode4* rootNode = segment.construct<CSNode4> (_RootNode) (alloc_void); rootNode->node0 = new CSNode4(alloc_void,...); this works until I try to static_cast node0 offset_ptr<CSNode4> N1 = static_cast<CSNode4*>(rootNode->node0); I get: (MSVC 2010, boost 1.42) error C2440: 'static_cast' : cannot convert from 'boost::interprocess::offset_ptr<PointedType>' to 'CSNode4 *' what am I doing wrong? Thanks, Ivan

2 1

Build boost with Apple's LLVM 3.0
by Daniel Dilts 29 Dec '11

29 Dec '11

I am building boost on OS X 10.7.2. Using ./bootstrap.sh ./b2 sudo ./b2 install it appears to build with the GCC 4.2.1 toolchain. How would I change this so that it builds using the LLVM 3.0 toolchain?

2 2

Using the /RTC option without specifying a debug runtime will lead to linker errors
by Sleat, Ben 28 Dec '11

28 Dec '11

Hi I'm trying to track down a very nasty stack corruption bug in my release code and therefore I would like to enabled the Visual C++ RTCs option to enable runtime stack checks in my release build, however when I try to do this I get an "Incompatible build options" error from the boost libraries. Specifically I get this from boosts AutoLink.hpp: #if defined(__MSVC_RUNTIME_CHECKS) && !defined(_DEBUG) # pragma message("Using the /RTC option without specifying a debug runtime will lead to linker errors") # pragma message("Hint: go to the code generation options and switch to one of the debugging runtimes") # error "Incompatible build options" #endif It seems to be suggesting that in order to use /RTC I need to do a Debug build, buts that's exactly what I don't want to do... I need to enable Runtime Checks in the Release build! Is there any way to get this to work in a release build that uses boost? Does anyone know the details of the incompatibility? Surely /RTC doesn't require all linked in DLLs also to be compiled with /RTC? Thanks in advance. Ben This email is from Verint Systems UK Ltd and is confidential. If you have received it in error, please advise us and then delete the original and any attachments it may have contained. Verint Systems UK Ltd does not accept any responsibility for viruses. Verint Systems UK Ltd is a limited company registered in England and Wales at 241 Brooklands Road, Weybridge, Surrey KT13 0RH ,registration number 2602824. VAT registration number GB566153238.

3 5

boost::asio::buffer + std::wstring
by Luke Walker 28 Dec '11

28 Dec '11

Hi, I'm sending unicode text over a socket using boost::asio::async_write and boost::asio::buffer however only 1/4 of the string ends up at the receiver. What must I do so that all bytes are sent? Thanks!

2 6

[Python] Wrapping Visitor Pattern and Object Slicing
by Alex Olivas 27 Dec '11

27 Dec '11

Hey All, I'm trying to wrap a third party lib that uses the visitor pattern and their own smart pointers ('ref_ptr' below), which manages objects that inherit from 'Referenced'. I've put together a simple example that illustrates the problem. Code for python bindings : http://codepad.org/wq47m5CI Simple test script : http://codepad.org/Jfme3U6U Output for two cases : http://codepad.org/gbFBxy04 Case 1) 'apply' override is commented out in the python class Case 2) 'apply' override exists The problem that I'm having is that the 'apply' method ( lines 83 - 86 ) slices everything to base unless I use boost::ref(). However this only works for wrapped classes and in this lib several classes use derived visitors that are not part of the public API ( which I modeled as HelperVisitor in the above example ). Is there anyway to prevent object slicing for both wrapped and unwrapped objects in this scenario? I'm building against boost 1.47 and if anyone's interested in digging deeper the 3rd party lib is Open Scene Graph 3.0.1. Thanks, Alex.

1 0

Re: [Boost-users] filesystem::path threadsafe ?? (1.48) Options
by Aris Basic 27 Dec '11

27 Dec '11

Here is the sample code that crashes every time i compile project as multibyte and not unicode and ahve user wchar_t as default type #include <boost/thread.hpp> #include <boost/filesystem.hpp> int main(void) { std::string sPath("c:\\Development"); boost::thread_group tg; for(int i = 0; i < 10; i++) { tg.create_thread([&sPath](){ boost::this_thread::sleep(boost::posix_time::milliseconds(10)); boost::filesystem::path p(sPath); boost::filesystem::directory_iterator di(p), end; while(di != end) std::cout << (*di).path().string() << std::endl; }); } tg.join_all(); }

3 3

Boost.Container string operator+ problem
by dave_chp 27 Dec '11

27 Dec '11

Using boost 1.48 and vs2010 gives me an error when trying to use boost::container::string. #include <boost/container/string.hpp> int main( int, char *[] ) { using boost::container::string; string hello = "hello "; string world = "world"; string hello_world = hello + world; } 1>d:\sdk\boost_1_48_0\boost\container\string.hpp(2368): error C2248: 'boost::container::containers_detail::basic_string_base ::alloc' : cannot access protected member declared in class 'boost::container::containers_detail::basic_string_base ' 1> with 1> [ 1> A=std::allocator<char> 1> ] 1> d:\sdk\boost_1_48_0\boost\container\string.hpp(214) : see declaration of 'boost::container::containers_detail::basic_string_base ::alloc' 1> with 1> [ 1> A=std::allocator<char> 1> ] 1> d:\tmp\xxx.cpp(15) : see reference to function template instantiation 'boost::container::basic_string<CharT,Traits,A> boost::container::operator +<char,std::char_traits<char>,std::allocator<_Ty>>(const boost::container::basic_string<CharT,Traits,A> &,const boost::container::basic_string<CharT,Traits,A> &)' being compiled 1> with 1> [ 1> CharT=char, 1> Traits=std::char_traits<char>, 1> A=std::allocator<char>, 1> _Ty=char 1> ] 1> d:\tmp\xxx.cpp(20) : see reference to function template instantiation 'void hello_world_test<boost::container::string>(void)' being compiled 1> template <class CharT, class Traits, class A> inline basic_string<CharT,Traits,A> operator+(const basic_string<CharT,Traits,A>& x, const basic_string<CharT,Traits,A>& y) { ... str_t result(reserve, x.size() + y.size(), x.alloc()); ... } should this maybe be x.get_allocator() instead of x.alloc()? -- View this message in context: http://boost.2283326.n4.nabble.com/Boost-Container-string-operator-problem-… Sent from the Boost - Users mailing list archive at Nabble.com.

2 2

[smart_ptr] Inclusion of unique_ptr
by Szymon Gatner 27 Dec '11

27 Dec '11

Hi, as suggested by Dave Abrahams I am now turning here with proposition of including unique_ptr<> to smart_ptr library. Newly accepted boost.move enables portable implementation and move-aware containers in boost.container allow to take full advantage of this now standard pointer type. Attaching proposed implementation. -- Szymon Gatner The Lordz Games Studio www.thelordzgamesstudio.com

3 2

whitebox testing with boost unit test framework?
by Chris Cleeland 26 Dec '11

26 Dec '11

I'm using the boost unit test framework to implement unit tests for code. I'm wondering if there is a best-practice for doing white-box testing/internal state inspection of types under test. My hack right now is to strip out "protected" and "private" from the header, but I hold my nose as I do that. Thoughts/suggestions? -- Chris Cleeland

7 16

A* heuristic
by giridhar 24 Dec '11

24 Dec '11

Hello All, I have a question about defining A* heuristic. I am trying to implement an algorithm in a paper using BGL. Here authors have used A* Dijkstra's to calculate shortest route with an additional constraint of route length should be no longer than a threshold value t. I think due to this threshold constraint they are using A* instead of normal Dijkstra's algorithm. I came to know A* is already there in Boost Graph Library. I just have a basic knowledge about A* algorithm that it finds the shortest route based on the heuristic H. I tried to look into the example in BGL, but I did not get any hint to define a heuristic. Can anybody give me some hints or some useful links of how can I define a heuristic for this particular scenario of finding the shortest path between nodes that is no longer than threshold t through A* Dijkstra. This would be really helpful for me to proceed further. -- Regards, Giridhar

5 5

Problem with boost ::interprocess::string
by Josmon Paul 23 Dec '11

23 Dec '11

3 2

filesystem::path threadsafe ?? (1.48)
by Aris Basic 22 Dec '11

22 Dec '11

is filesystem::path threadsafe ? i think im seeing issues related to conversion of std::string to std::wstring (that is being used by path on windows) (so thats put blame onto string to wstring conversion) did anyone see anything like that ? if not ill try to create a small sample app that recreates the issue. code portion <similar code run in multiple threads> std::string spath("c:\\somefolder"); fs::path path(spath); // i get crash within this call seems like conversion is using static instance of codecvt and it breaks on call in (do_in) maybe its just windows codecvt issue

1 0

Using boost::uuids::uuid as a map index
by Tim Burgess 22 Dec '11

22 Dec '11

Hi, I'm new to using boost and have hit a problem using UUID. I have a set of classes that have UUID variables to provide unique identifiers. I wish to achieve two things: 1 - Allow objects to reference each other based on their UUID values (imagine the usual databasing student/teacher/course models); 2 - Maintain std::map collections of objects of the same class. Initially, I made the mistake of creating a class instance containing my UUID then inserting it into a map: Std::map <boost::uuid::uid, myClass> myMap; The index of the entry was set as follows: Std::pair <boost::uuids::uuid, myClass> myPair; myPair = std::make_pair( myClassInstance.UUIDField, myClassInstance); myMap.insert( myPair); All look-ups within the map based on the UUID then fail, as adding the object to the map is essentially a copy operation and UUID is non-copyable, so new unique identifiers were generated. I then tried: Std::map <boost::uuids::uuid *, myClass*> myMap; I thought that this should work as the actual UUID value would only ever be held in a single instance of myClass and the relationships between objects could be maintained by following the pointers. Unfortunately, look-ups using this scheme also fail and I can't see where I'm going wrong. Can anybody advise, please? Best wishes. Tim Burgess Raised Bar Ltd Phone: +44 (0)1827 719822 Don't forget to vote for improved access to music and music technology at http://www.raisedbar.net/petition.htm -----Original Message----- From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Cromwell Enage Sent: 10 December 2011 05:42 To: boost-users(a)lists.boost.org Subject: [Boost-users] [boost-users][container] associative placement insertion Hi, all! I'm wondering how placement insertion works for pair-associative Boost.Container types. For example, given: //[ex_code struct D { D(char,char) {} // Insert Boost.Move awareness here... }; boost::container::map<int,D> my_map; //] Will my_map.emplace(0, 't', 'p') call D('t', 'p') and move the object into the map? Will Boost.Unordered work the same way? TIA! Cromwell D. Enage _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

3 4

boost::polygon::polygon_set
by Egon Schaal 22 Dec '11

22 Dec '11

Hello I have a question to use the function template <typename T, typename coord_type> T& simplify(T& polygon_set, distance_type threshold) How must I define the parameter distance_type My typedefs are set to typedef boost::polygon::point_data<double> point; typedef boost::polygon::polygon_set_data<double> polygon_set; typedef boost::polygon::polygon_with_holes_data<double> polygonwh; typedef boost::polygon::polygon_data<double> polygon; I think the distance_type must be a double. Mit freundlichen Grüßen / Best regards Egon Schaal ///////////////////////////////////////////////// Egon Schaal CAD-Consulting, Softwareerstellung Aspacherstr. 15 71522 Backnang Email egon.schaal(a)cad-cons.net Web http://www.cad-cons.com Tel (+49)7191-84498 Fax (+49)7191-71410 SteuerNr: 51336/01006 /////////////////////////////////////////////////

1 0

Please help me to choose a container
by Jayden Shui 21 Dec '11

21 Dec '11

Hi All, I have a number of named objects of type B whose name can be accessed by B::Name(). B is polymorphic. D1, D2 and so on are derived from B. I want to put them in a set or map-like container ordered by their names. They are referenced by other objects, such as of type C. If the objects in the container are changed by its type (from type D1 to D2) or value, their users can know it automatically, i.e. those information is shared among owners and users. To erase an object in the container, first we need to ensure it is not be used by other objects. Please help me on choose a proper container with smart pointers. I am struggling with it by trying multi-index-container, pointer container, standard container, and cannot find a good way. Thanks a lot ! ! Best regards, Jayden

4 5

How to make multi_index_container work with std::unique_ptr?
by Jayden Shui 21 Dec '11

21 Dec '11

Hi All, If the elements of a multi_index_container are std::unique_ptr, it doesn't seem to work because the assignment operator of std::unique_ptr is private. Any way to let it work? If I change unique_ptr to shared_ptr, it works. But I need a good performance. Or is there anyway to work around to get pointer container performance with multi index power? Thanks a lot! Jayden

3 10