August 2002 - Boost-users - lists.preview.boost.org

RE: [Boost-Users] Getting the hang of Boost::Bind
by Tom Matelich 09 Aug '02

09 Aug '02

> -----Original Message----- > From: Duane Murphy [mailto:duanemurphy@mac.com] > Sent: Friday, August 09, 2002 3:23 PM > To: Boost Users > Subject: Re: [Boost-Users] Getting the hang of Boost::Bind > > > --- At Fri, 9 Aug 2002 15:08:06 -0700, Tom Matelich wrote: > > >I have a vector of > > > >class Landmark > >{ > >public: > > std::string const& getName() const; > >... > >}; > > > >I want to do a find_if for a name that I have. > > > >something like > >std::find_if(begin, end, boost::bind(std::equal<std::string>(???, > >name_to_find))); > > > >What do I put for the ??? ? > > Nothing. Your done. :-) bind takes a pointer to a function > (among other > things) as the first parameter. It then calls that function with the > parameters you specify. You use _1, etc for parameters that > are input to > bind. In your case: > > std::find_if(begin, end, boost::bind(std::equal<std::string>, > name_to_find, _1))); > But I have to compare name_to_find to the result of _1.getName() don't I? ----------------------------------------------------------------------- DISCLAIMER: Information contained in this message and/or attachment(s) may contain confidential information of Zetec, Inc. If you have received this transmission in error, please notify the sender by return email. -----------------------------------------------------------------------

1 0

Signals - no linking
by michael graves ii 09 Aug '02

09 Aug '02

hey, when trying to run a program using boost::signal i am getting a lot of unresolved errors. [output window] --------------------Configuration: my_dlls - Win32 Release-------------------- Linking... delegate_main.obj : error LNK2001: unresolved external symbol "public: __thiscall boost::signals::detail::signal_base::~signal_base(void)" (??1signal_base@detail@signals@boost@@QAE@XZ) delegate_main.obj : error LNK2001: unresolved external symbol "protected: __thiscall boost::signals::trackable::~trackable(void)" (??1trackable@signals@boost@@IAE@XZ) delegate_main.obj : error LNK2001: unresolved external symbol "public: void __thiscall boost::signals::connection::disconnect(void)const " (?disconnect@connection@signals@boost@@QBEXXZ) delegate_main.obj : error LNK2001: unresolved external symbol "protected: void __thiscall boost::signals::detail::slot_base::create_connection(void)" (?create_connection@slot_base@detail@signals@boost@@IAEXXZ) delegate_main.obj : error LNK2001: unresolved external symbol "public: __thiscall boost::signals::detail::signal_base_impl::signal_base_impl(class boost::function2<bool,class boost::any,class boost::any,struct boost::empty_function_policy,struct boo st::empty_function_mixin,int> const &)" (??0signal_base_impl@detail@signals@boost@@QAE@ABV?$function2@_NVany@boost@@ V12@Uempty_function_policy@2@Uempty_function_mixin@2@H@3@@Z) delegate_main.obj : error LNK2001: unresolved external symbol "public: class boost::signals::connection __thiscall boost::signals::detail::signal_base_impl::connect_slot(class boost::any const &,class boost::any const &,class std::vector<class boost ::signals::trackable const *,class std::allocator<class boost::signals::trackable const *> > const &)" (?connect_slot@signal_base_impl@detail@signals@boost@@QAE?AVconnection@34@AB Vany@4@0ABV?$vector@PBVtrackable@signals@boost@@V?$allocator@PBVtracka ble@signals@boost@@@std@@@std@@@Z) delegate_main.obj : error LNK2001: unresolved external symbol "public: __thiscall boost::signals::detail::call_notification::~call_notification(void)" (??1call_notification@detail@signals@boost@@QAE@XZ) delegate_main.obj : error LNK2001: unresolved external symbol "public: __thiscall boost::signals::detail::call_notification::call_notification(class boost::shared_ptr<class boost::signals::detail::signal_base_impl> const &)" (??0call_notification@de tail@signals@boost@@QAE@ABV?$shared_ptr@Vsignal_base_impl@detail@signals@boo st@@@3@@Z) delegate_main.obj : error LNK2001: unresolved external symbol "public: __thiscall boost::signals::detail::signal_base_impl::~signal_base_impl(void)" (??1signal_base_impl@detail@signals@boost@@QAE@XZ) Release/my_dlls.exe : fatal error LNK1120: 9 unresolved externals Error executing link.exe. my_dlls.exe - 10 error(s), 0 warning(s) [/output window] so in semi-readable for these are the unresolved symbols: signal_base::~signal_base(void) trackable::~trackable(void) void connection::disconnect(void)const void slot_base::create_connection(void) signal_base_impl::signal_base_impl(class boost::function2<bool,class boost::any,class boost::any,struct boost::empty_function_policy,struct boost::empty_function_mixin,int> const &) connection signal_base_impl::connect_slot(class boost::any const &,class boost::any const &,class std::vector<class boost::signals::trackable const *,class std::allocator<class boost::signals::trackable const *> >const &) call_notification::~call_notification(void) call_notification::call_notification(class boost::shared_ptr<class boost::signals::detail::signal_base_impl> const &) signal_base_impl::~signal_base_impl(void) i downloaded the signals library out of the CVS Repository. i see that some people have gotten signals to work so i guess i'm missing something=( i like this lib a lot (and it saves me from coding it=), but i would have went with a delegate/callback naming scheme instead of signal/slot. i guess that's what find and replace is for=). michael graves ii

3 6

No time/date class in boost?
by Sean Shubin 09 Aug '02

09 Aug '02

I would have expected to find a time/date class in boost. Was it determined to be unnecessary, or is it simply that no one has gotten around to implementing one?

4 3

Regex issue on WIN32
by Rob Reece 09 Aug '02

09 Aug '02

I'm trying to get the regex lib (boost 1.28.0) built on win32 (MSVC v6, stlport 4.5.3). The standard build that is provided with regex appears to work fine and I get the full compliment of regex libraries (debug, static/dynamic, etc.). However, when I attempt to build the credit_card_example file, the link fails with unresolved external symbols. I then added the 13 regex source files to a msdev project along with the credit_card_example source file and linked everything statically (using BOOST_REGEX_STATIC_LINK or whatever it is). That worked fine. So this leads me to believe that something is going on with BOOST_REGEX_DECL macro. I put some #pragma message(...) statements into some headers and determined that the macro is being defined correctly. Is it possible that this macro is missing on some functions/classes or is it more likely a build option or macro issue? The first unresolved symbol I have is boost::re_detail::match_results_base<...>::m_free(...) As I was looking around for that symbol, I discovered in regex.hpp that match_results_base did not have BOOST_REGEX_DECL macro on the class definition. I added it and rebuilt and I ended up with more unresolved symbols. So obviously that isn't the direction to go. I have, however, not been able to find the actual definition of m_free yet (still looking). Thanks -Rob

2 1

Graph: Generic access to vertex/edge properties
by Tarjei Knapstad 09 Aug '02

09 Aug '02

Hi. I'm currently trying to implement a generic pattern matching (aka subgraph isomorphism) algorithm for use with the Boost Graph Library. My first-attempt function signature looks like this (comments included for further description of what I'm attempting) //! Seeks to find matches of the graph \a g2 in the graph \a g1. /*! This is called "graph pattern matching", or "subgraph homomorphism/isomorphism". The results are returned in a std::list of std::maps where the maps' key is the node_descriptor in \a g2 and the values are the corresponding node_descriptors in \a g1. The size of the returned list represents the number of matches. If \a properties is true it means that all vertex and edge properties must be equal in both structures for a match to be found. Otherwise, only the graph structure itself will be checked. \sa positioned_pattern_match */ template <class Graph> std::list< std::map<typename graph_traits<Graph>::vertex_descriptor, typename graph_traits<Graph>::vertex_descriptor> > pattern_match(const Graph& g1, const Graph& g2, bool properties = true); For the case where the 'properties' switch is false I have everything I need, but if 'properties' is true I'm a bit unsure on how to proceed. The problem, as I see it, is to do a generic consecutive access of all the properties of the current vertex/edge being checked and see if they're equal in both 'g1' and 'g2'. Could anyone provide me a solution/clue on how to solve this problem in a generic way so that the algorithm can be used for any graph? Regards, -- Tarjei Knapstad

3 2

VC7 build error without #define BOOST_DISABLE_WIN32
by Martin Schuerch 08 Aug '02

08 Aug '02

Hi I have an application with MFC / ATL and also some files compiled with the /clr option. Throuout the application boost is used a lot. All builds well as long as #define BOOST_DISABLE_WIN32 is set in the user.hpp file. Without this option a) the build hangs during registration after linking or b) link error due to differently defined custom attributes (in a file using /clr option) Did anybody had similar problems already? Regards Martin

1 0

iterator_adaptor and operator-> for input iterators
by Beman Dawes 07 Aug '02

07 Aug '02

I wrote an iterator to do recursive directory iteration. The heart of it is: template< typename Predicate > class recursive_directory_iterator : public boost::iterator_adaptor< boost::shared_ptr< detail::rdi_imp< Predicate > >, detail::rdi_policies, const boost::filesystem::path, const boost::filesystem::path &, const boost::filesystem::path *, std::input_iterator_tag, std::ptrdiff_t > { ... }; Works fine as long as you stay away from operator->. For example, fs::recursive_directory_iterator<pred_type> rdi( dir , dummy ); fs::recursive_directory_iterator<pred_type> rdi_end; for ( ; rdi != rdi_end; ++rdi ) { // std::cout << rdi->generic_path() << std::endl; std::cout << (*rdi).generic_path() << std::endl; } works as expected. But if you uncomment the commented line, the program fails in the call to operator->. What "fails" means depends on the execution environment; whatever is happening seems to confuse the debugger, stepping doesn't shed much light on the problem. Same symptoms with both VC++7 and Intel 6.0. I suppose I'm doing something stupid, but don't have a clue as to what. I notice in iterator_adaptor_test.cpp that operator-> is not actually exercised. Is it possible there is a bug in it for input iterators? I've not had similar problems with iterator_adaptor for bidirectional iterators. Any help appreciated, --Beman

1 0

Newbie and his template for comments.
by Kamil Burzynski 07 Aug '02

07 Aug '02

Hello. I'm a C++ developer, who is learning STL recently, and loving it :) I've encountered Boost library, which seems to extending STL funcationality a lot :) I've also created a sampel template for usage in my company, and I would like to get comments about it: is this code ok, exception safe, somebody did it better things like that. In my projects I'm often using structures like map<T1, T2 *>, e.g. map<int, Point *> or map<string, Person*> or something like this. So, often I want to do something like that: map<int, Point *> my_map; map<int, Point *>::iterator it; /* .. */ for( it=my_map.begin();it!=my_map.end();++it ) { it->second->Reset(); //sets x,y to 0,0 } example may be stupid, but shows what I'm trying to explain. To improve it I've created a template (given below), so I ca use it like that: for_each( my_map.begin(), my_map.end(), map_fun( &Point::Reset ) ); Which i think is much better. My template is as follows (style is kept from GCC includes, so it may be not as readable as it could be :) template <class _Ret, class _Tp> class map_fun_t : public unary_function<_Tp*,_Ret> { public: explicit map_fun_t(_Ret (_Tp::*__pf)()) : _M_f(__pf) {} template< class _Mp> _Ret operator()(_Mp &__p) const { return ((__p.second)->*_M_f)(); } private: _Ret (_Tp::*_M_f)(); }; template <class _Ret, class _Tp> inline map_fun_t<_Ret,_Tp> map_fun(_Ret (_Tp::*__f)()) { return map_fun_t<_Ret,_Tp>(__f); } What do you think about it? Has it any flaws? Somebody done it already? Is it usable for anyone except me? :) Thanks in advance. -- Best regards from Kamil Burzynski Senior Design Engineer Advanced Digital Broadcast Poland, LTD. - - "Yes, I'm criminal. My crime is that of curiosity."

4 6

Regex++ link problem with VC6 when building with _UNICODE defined
by Edward Diener 07 Aug '02

07 Aug '02

If I build boost 1.28 regex with _UNICODE defined and then attempt to link the static mssd.lib version with a _UNICODE application using the library, I get: boost_regex_vc6_mssd.lib(w32_regex_traits.obj) : error LNK2005: _iswspace already defined in libcmtd.lib(_wctype.obj) boost_regex_vc6_mssd.lib(c_regex_traits.obj) : error LNK2005: _iswalpha already defined in libcmtd.lib(_wctype.obj) boost_regex_vc6_mssd.lib(c_regex_traits.obj) : error LNK2005: _iswupper already defined in libcmtd.lib(_wctype.obj) boost_regex_vc6_mssd.lib(c_regex_traits.obj) : error LNK2005: _iswlower already defined in libcmtd.lib(_wctype.obj) boost_regex_vc6_mssd.lib(c_regex_traits.obj) : error LNK2005: _iswdigit already defined in libcmtd.lib(_wctype.obj) boost_regex_vc6_mssd.lib(c_regex_traits.obj) : error LNK2005: _iswxdigit already defined in libcmtd.lib(_wctype.obj) boost_regex_vc6_mssd.lib(c_regex_traits.obj) : error LNK2005: _iswspace already defined in libcmtd.lib(_wctype.obj) boost_regex_vc6_mssd.lib(c_regex_traits.obj) : error LNK2005: _iswpunct already defined in libcmtd.lib(_wctype.obj) boost_regex_vc6_mssd.lib(c_regex_traits.obj) : error LNK2005: _iswcntrl already defined in libcmtd.lib(_wctype.obj) Debug/TestRegularExpressionGUIStatic.exe : fatal error LNK1169: one or more multiply defined symbols found Error executing link.exe. This only occurs in the debug multi-threaded static library version. Has anyone else seen this or know why it might occur ? If I change the build options for this library from /Od /Gz to /O2, everything works fine and no linker errors occur.

2 1

[BGL] Common children for vertices in DAG
by Erik Arner 07 Aug '02

07 Aug '02

Is there a fast way, with or without preprocessing of the graph, for checking if two non-adjacent vertices in a DAG have one or more common children? Any pointers to components of the BGL that implement, or can be used to implement, this task would be much appreciated. Thanks, Erik

2 4

Tuple from cons list
by j1k1cki 07 Aug '02

07 Aug '02

Hi, Is there a simple way of obtaining a tuple type out of cons list? It also seems natural to build tuple type from two MPL iterators. Is such code available anywhere already? Best regards

1 0

BGL: Problem with parallel edges and filtered_graph
by Michael Kettner 06 Aug '02

06 Aug '02

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi Jeremy, I think I discovered a problem concerning filtered_graphs and parallel edges: Assume I have a graph containing two edges E1 and E2 connecting node A and node B. Now I crate a boost::filtered_graph (myFilteredGraph) with a filter that returns true for only E1. When I now try to get E1 by calling edge = boost::edge( A, B, myFilteredGraph ).first; the result is undefined. Looking at the code (filtered_graph.hpp) I found out that the edge is return by: edge(typename filtered_graph<G, EP, VP>::vertex_descriptor u, typename filtered_graph<G, EP, VP>::vertex_descriptor v, const filtered_graph<G, EP, VP>& g) { typename G::edge_descriptor e; bool exists; tie(e, exists) = edge(u, v, g.m_g); return std::make_pair(e, exists && g.m_edge_pred(e)); } Here, the line tie(e, exists) = edge(u, v, g.m_g); returns _some_ edge, but not necessarily the _right_ one. The call edge(...) is not called for the filtered graph and g.m_edge_pred(e) is called _after_ getting the wrong edge (resulting in a return value FALSE). One solution would be to call boost::edge_range(A, B, myFilteredGraph) on my filtered_graph to get all visible edges, but this function is not provided. Any ideas how to solve my problem? Michael - -- http://www.ive.uni-hannover.de # kettner(a)ive.uni-hannover.de -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE9TqUAkCdGnb0kVFMRAlsLAJwKJJ2NSLRu2HUv/H4sAhr4W5WdkACdHXZ6 3kz8fBDvysWKc1vxd5rf/CE= =l+NV -----END PGP SIGNATURE-----

2 3

BGL: dijkstra_shortest_paths and parallel edges
by Michael Kettner 06 Aug '02

06 Aug '02

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, my former posting leads me to another question: How does the dijkstra_shortest_paths behave if applied to a multigraph? And how does the dijkstra_shortest_paths behave if applied to a filtered_(multi)graph containing parallel edges, but with only _one_ of the parallel edges visible respectively? Michael - -- http://www.ive.uni-hannover.de # kettner(a)ive.uni-hannover.de -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE9TqprkCdGnb0kVFMRApGUAJ9nzr3Y4ijbrNnWENzxYIwcdLy8iQCfX2fx dl0M/IUt2bWFL0H9ovwajm4= =+FTJ -----END PGP SIGNATURE-----

2 1

BGL example boost_web_graph.expected
by Arjun Bijanki 06 Aug '02

06 Aug '02

When I compile and run Boost_1_28_0/libs/graph/example/boost_web_graph.cpp my output differs from the expected output: 1c1 < The diameter of the boost web-site graph is 2 --- > The diameter of the boost web-site graph is 3 Is the expected file current? Thanks, Arjun Bijanki Microsoft VC++ [Non-text portions of this message have been removed]

2 1

Why stop building with error "Thread support is unavailable!"
by xuejm 06 Aug '02

06 Aug '02

Hi, I installed boost1.28.0 with microsoft visual c++ .NET and regex worked very well, but when I build a very simple example to test boost.thread, it stop building with error "Thread support is unavailable!". I found out that it's because that there's not a pre-define variable defined. Can I define the variable? How can I use boost.thread in my vc++ .net? TIA Phipps Xue

2 1

Re: [Boost-Users] Re: Logical AND
by dan.ellis＠sophos.com 05 Aug '02

05 Aug '02

On 08/03/2002 05:04:26 PM news wrote: > > I need a match on "a AND is" when searching a sentence like "This is a > > test". >Regular expressions match sequences of characters. Your match says to match >a string when both of 2 different matching possibilities exist anywhere in >the string. To do this you must use 2 separate regular expression matches >separating them by the normal C++ "&&" operator. Maybe I'm misunderstanding what's wanted, but wouldn't is.*a do what he wants? Or if they need to be matched in either order: (is.*a)|(a.*is) It doesn't scale well, of course. -- Dan Ellis, Software Engineer, Sophos Anti-Virus Email: dan.ellis(a)sophos.com, DDI: 01235 540204 Real Business/CBI Growing Business Awards: Company of the Year Tel: 01235 559933, Web: http://www.sophos.com/

2 1

uBLAS Observation: terrible execution speed for prod(matrix,prod(matrix,prod(matrix,matrix)))
by Walter Bowen 05 Aug '02

05 Aug '02

Hi, I am new to uBLAS. I am looking to see if it will be useful for my application (I develop 6-Degrees-of-freedom flight simulations used to analyze avionics systems.) I have benchmarked a few lines of code with RogueWave's Math.h++ (testing for execution speed) and made the following observation. Observation 1) For matrix products of two small (~3-by-3) matrices ( i.e., prod(smallMat1, smallMat2) ) uBLAS executes MUCH FASTER than Math.h++. Observation 2) For matrix produces of two large matrices (100 by 100) uBLAS and Math.h++ give similar execuation speed. Obervation 3) (This is the kicker...) for strung-together matrix products like "Mat1 * Mat2 * Mat3 * Mat4 * Mat5", which I am implementing as "prod(Mat1, prod(Mat2, prod( Mat3, prod(Mat4,Mat5) ) ) ) Math.h++ is MUCH MUCH FASTER than uBLAS. -- by ~2 orders OF MAGNITUDE! I believe that this is a characteristic of the scalability of template expressions. My question is this: Is there a way I an instruct uBLAS not to use template expressions when for strung-together matrix products? Regards, Walt

5 4

Logical AND
by Mads M.P. 05 Aug '02

05 Aug '02

I've been looking for a parameter like "AND" when using regular expressions (from boost 1.28). I need a match on "a AND is" when searching a sentence like "This is a test". Is there a way to create such a search string by using regular expressions ? Regards Mads c(a)medit.dk

3 2

Boost 1.28 Regex and VC6 link problem
by Edward Diener 04 Aug '02

04 Aug '02

Using Boost 1.28 and regex I get linker errors regarding raw_storage. I believe someone has brought this up before but I didn't save the previous answer. error LNK2001: unresolved external symbol "public: class boost::detail::allocator_adapter<char,class boost::detail::simple_alloc> __fastcall boost::re_detail::raw_storage<class boost::detail::allocator_adapter<char,class boost::detail::simple_alloc> >::allocator(void)const " error LNK2001: unresolved external symbol "public: class boost::detail::allocator_adapter<char,class boost::detail::simple_alloc> __fastcall boost::re_detail::raw_storage<class boost::detail::allocator_adapter<char,class boost::detail::simple_alloc> >::allocator(void)const " error LNK2001: unresolved external symbol "public: __thiscall boost::re_detail::raw_storage<class boost::detail::allocator_adapter<char,class boost::detail::simple_alloc> >::raw_storage<class boost::detail::allocator_adapter<char,class boost::detail::simple_alloc> >(class re_detail::detail::allocator_adapter<char,class boost::detail::simple_alloc> const &)" error LNK2001: unresolved external symbol "public: __thiscall boost::re_detail::raw_storage<class boost::detail::allocator_adapter<char,class boost::detail::simple_alloc> >::raw_storage<class boost::detail::allocator_adapter<char,class boost::detail::simple_alloc> >(class re_detail::detail::allocator_adapter<char,class boost::detail::simple_alloc> const &)" error LNK2001: unresolved external symbol "public: void * __fastcall boost::re_detail::raw_storage<class boost::detail::allocator_adapter<char,class boost::detail::simple_alloc> >::insert(unsigned int,unsigned int)" error LNK2001: unresolved external symbol "public: void __fastcall boost::re_detail::raw_storage<class boost::detail::allocator_adapter<char,class boost::detail::simple_alloc> >::resize(unsigned int)" It seems to be related to these lines in instances.hpp template class re_detail::raw_storage< BOOST_DEFAULT_ALLOCATOR BOOST_REGEX_CHAR_T) >; template class BOOST_REGEX_DECL re_detail::raw_storage<BOOST_DEFAULT_ALLOCATOR(BOOST_REGEX_CHAR_T) >; Are these lines in error ? Should one or both of them be removed ? My guess is that the line with BOOST_REGEX_DECL needs to be removed.

1 1

Problems with mpl::find and std library
by Tanton Gibbs 03 Aug '02

03 Aug '02

I had a problem with using mpl::find and the std::find at the same time. Basically, my compiler, Compaq C++ V6.5-026, notes an ambiguity in find.hpp between the find_if that it uses and the find_if in the STL. I changed the line that reads struct find : find_if< Sequence, same_as<T> > {}; to be struct find : mpl::find_if< Sequence, same_as<T> > {}; and it works fine. I'm not sure if this is a compiler bug or if we need to find other occurences like this one and fix them. Any help is appreciated. Tanton

2 2

boost.python - from_python for obj.__class__
by Nikolay Mladenov 02 Aug '02

02 Aug '02

Hi, I have exported some classes to python with boost.python, and now I am wondering: Does any body know how can I convert obj.__class__ (of an exported object from C++) to a class specific value( for example typeid(corespondong_cpp_class) )? Thanks in advance, Nikolay

1 0

bjam issue related to boost::python
by Srivatsan Raghavan 02 Aug '02

02 Aug '02

hi all , i created a c++ extension module using python which worked fine.. then i wanted to embed a call to PyRun_SimpleFile in another app, and the script i was calling is attempting to use my extension module but i was getting telling me that the interpreter wasn't initialized after much searching, research, and work with msvc's Dependency Walker i narrowed it down to the fact that boost_python_debug.dll is trying to link to the release version of python22.dll , whereas it should be linking to python22_d.dll (which unfortunately does not come with the python installer , that has to be compiled manually ) at any rate, how can the boost::python Jamfile be modified to try this check when it comes boost::python ? --vat ==.sig== Evil requires nothing more to win than that good men do nothing

1 0

[BGL] Vertex removal without iterator invalidation?
by Erik Arner 01 Aug '02

01 Aug '02

Yet another question from the BGL newbie... I understand that performing remove_vertex() on graphs with vertexList=vecS will result in invalidated itarors and descriptors for the graph. However, some toy examples i made suggest that if I remove a vertex in such a graph, the vertex descriptors and vertex iterators for vertices with *lower* ID than the removed vertex remain valid after removal, while those for higher ID vertices are invalidated. Is this a true feature of a graph with Vertexlist=vecS, or is my observation a mere coincidence? Is it safe to write code that exploits this "feature"? If it indeed is a feature, I can construct a sorted list of vertices to remove, and remove the vertices in descending order in an easy fashion. If it is not a feature, any suggestions on how to perform this task i.e. removing a list of vertices while keeping the VertexList type vecS? Thanks, Erik

2 2

collection container
by Bohdan 01 Aug '02

01 Aug '02

Has boost any plans on creating container, that holds data by pointer, not by value? Rationale: It is impossible to use normally vector<...> for types that do not have copy constructor. Interface of vector< shared_ptr<...> > doesn't seems to be very convenient( for example with std::algorithms ). And most of all it is not good idea to show vector< shared_ptr<...> > interface to user of my lib, that wants to have container::iterator with normal behavior. AFAIK majority of existing libraries have/need such container ? As to me it is strange that neither stl nor boost have such class. I'm missing 'something' and there are important reasons for not doing this ?

2 5

Creating groups of regular expressions
by cyndi_r2002 01 Aug '02

01 Aug '02

Hi, I have started using Regex++ and like it a lot but is there a way to use grouping constructs using Regex++ / any alternative that would provide the same functionality? Thanks, Cyndi

2 1