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

Re: [Boost-users] Un-nesting a class
by Sohail Somani 17 Feb '06

17 Feb '06

> -----Original Message----- > From: boost-users-bounces(a)lists.boost.org > [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Perry Smith > Sent: Friday, February 17, 2006 11:24 AM > To: boost-users(a)lists.boost.org > Subject: [Boost-users] Un-nesting a class > > I have a template like: > > template <typename Z> > class foo { // ... > > I know that Z has the form A::B::C (three levels of nesting). Does > boost have a way for me to define a type which refers to A::B? Oops. I think I meant: template<typename Z> class foo { typedef typename Z::B zb; }; class A { class B { }; }; foo<A> a;

1 0

[tuple, lambda] predicate does not compile
by Christian Rössel 17 Feb '06

17 Feb '06

Hello Newsgroup, in the following code the call bind (&boost::tuple<int, double>::get<0>, _1) does not compile whereas an analogous call with a non-template parameter compiles fine. What am I doing wrong? I'm using boost 1.33.1 and Visual Studio 7.1 Thanks in advance, Christian #include <vector> #include <algorithm> #include <string> #include <boost/lambda/lambda.hpp> #include <boost/lambda/bind.hpp> #include <boost/tuple/tuple.hpp> class SearchForMe { std::string a_; public: std::string getA () {return a_;} }; int main(int argc, char* argv[]) { using namespace std; using namespace boost::lambda; vector<SearchForMe> foo; // compiles fine find_if (foo.begin (), foo.end (), bind (&SearchForMe::getA, _1) == "apple"); vector< boost::tuple<int, double> > bar; // does not compile find_if (bar.begin (), bar.end (), bind (&boost::tuple<int, double>::get<0>, _1) == 15); return 0; } The error messages are: Compiling... boost_lambda.cpp d:\home\roe\c++_tests\boost_lambda\boost_lambda\boost_lambda\boost_lambda.cpp(31) : error C2784: 'const boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::action<2,boost::lambda::function_action<2,Result>>,detail::bind_tuple_mapper<const Arg1,const Arg2>::type>> boost::lambda::bind(const Arg1 &,const Arg2 &)' : could not deduce template argument for 'overloaded function type' from 'overloaded function type' d:\home\roe\boost_1_33_1\boost\lambda\detail\bind_functions.hpp(232) : see declaration of 'boost::lambda::bind' d:\home\roe\c++_tests\boost_lambda\boost_lambda\boost_lambda\boost_lambda.cpp(31) : error C2784: 'const boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::action<2,boost::lambda::function_action<2,Result>>,detail::bind_tuple_mapper<const Arg1,const Arg2>::type>> boost::lambda::bind(const Arg1 &,const Arg2 &)' : could not deduce template argument for 'overloaded function type' from 'overloaded function type' d:\home\roe\boost_1_33_1\boost\lambda\detail\bind_functions.hpp(232) : see declaration of 'boost::lambda::bind' d:\home\roe\c++_tests\boost_lambda\boost_lambda\boost_lambda\boost_lambda.cpp(31) : error C2784: 'const boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::action<Arity,Act>,detail::bind_tuple_mapper<const Arg1,const Arg2>::type>> boost::lambda::bind(const Arg1 &,const Arg2 &)' : could not deduce template argument for 'overloaded function type' from 'overloaded function type' with [ Arity=2, Act=boost::lambda::function_action<2> ] d:\home\roe\boost_1_33_1\boost\lambda\detail\bind_functions.hpp(212) : see declaration of 'boost::lambda::bind' d:\home\roe\c++_tests\boost_lambda\boost_lambda\boost_lambda\boost_lambda.cpp(31) : error C2784: 'const boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::action<Arity,Act>,detail::bind_tuple_mapper<const Arg1,const Arg2>::type>> boost::lambda::bind(const Arg1 &,const Arg2 &)' : could not deduce template argument for 'overloaded function type' from 'overloaded function type' with [ Arity=2, Act=boost::lambda::function_action<2> ] d:\home\roe\boost_1_33_1\boost\lambda\detail\bind_functions.hpp(212) : see declaration of 'boost::lambda::bind' d:\home\roe\c++_tests\boost_lambda\boost_lambda\boost_lambda\boost_lambda.cpp(31) : error C2784: 'const boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::action<Arity,Act>,detail::bind_tuple_mapper<const Arg1,const Arg2>::type>> boost::lambda::bind(const Arg1 &,const Arg2 &)' : could not deduce template argument for 'overloaded function type' from 'overloaded function type' with [ Arity=2, Act=boost::lambda::function_action<2> ] d:\home\roe\boost_1_33_1\boost\lambda\detail\bind_functions.hpp(212) : see declaration of 'boost::lambda::bind' d:\home\roe\c++_tests\boost_lambda\boost_lambda\boost_lambda\boost_lambda.cpp(31) : error C2784: 'const boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::action<2,boost::lambda::function_action<2,Result>>,detail::bind_tuple_mapper<Result(__cdecl &)(Par1),const Arg2>::type>> boost::lambda::bind(Result (__cdecl &)(Par1),const Arg2 &)' : could not deduce template argument for 'overloaded function type' from 'overloaded function type' d:\home\roe\boost_1_33_1\boost\lambda\detail\bind_functions.hpp(190) : see declaration of 'boost::lambda::bind' d:\home\roe\c++_tests\boost_lambda\boost_lambda\boost_lambda\boost_lambda.cpp(31) : error C2784: 'const boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::action<2,boost::lambda::function_action<2,Result>>,detail::bind_tuple_mapper<Result(__cdecl &)(Par1),const Arg2>::type>> boost::lambda::bind(Result (__cdecl &)(Par1),const Arg2 &)' : could not deduce template argument for 'overloaded function type' from 'overloaded function type' d:\home\roe\boost_1_33_1\boost\lambda\detail\bind_functions.hpp(190) : see declaration of 'boost::lambda::bind' d:\home\roe\c++_tests\boost_lambda\boost_lambda\boost_lambda\boost_lambda.cpp(31) : error C2784: 'const boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::action<2,boost::lambda::function_action<2,Result>>,detail::bind_tuple_mapper<Result(__cdecl &)(Par1),const Arg2>::type>> boost::lambda::bind(Result (__cdecl &)(Par1),const Arg2 &)' : could not deduce template argument for 'overloaded function type' from 'overloaded function type' d:\home\roe\boost_1_33_1\boost\lambda\detail\bind_functions.hpp(190) : see declaration of 'boost::lambda::bind' d:\home\roe\c++_tests\boost_lambda\boost_lambda\boost_lambda\boost_lambda.cpp(31) : error C2780: 'const boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::action<1,boost::lambda::function_action<1,Result>>,detail::bind_tuple_mapper<const Arg1>::type>> boost::lambda::bind(const Arg1 &)' : expects 1 arguments - 2 provided d:\home\roe\boost_1_33_1\boost\lambda\detail\bind_functions.hpp(91) : see declaration of 'boost::lambda::bind' d:\home\roe\c++_tests\boost_lambda\boost_lambda\boost_lambda\boost_lambda.cpp(31) : error C2780: 'const boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::action<Arity,Act>,detail::bind_tuple_mapper<const Arg1>::type>> boost::lambda::bind(const Arg1 &)' : expects 1 arguments - 2 provided with [ Arity=1, Act=boost::lambda::function_action<1> ] d:\home\roe\boost_1_33_1\boost\lambda\detail\bind_functions.hpp(71) : see declaration of 'boost::lambda::bind' d:\home\roe\c++_tests\boost_lambda\boost_lambda\boost_lambda\boost_lambda.cpp(31) : error C2780: 'const boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::action<1,boost::lambda::function_action<1,Result>>,detail::bind_tuple_mapper<Result(__cdecl &)(void)>::type>> boost::lambda::bind(Result (__cdecl &)(void))' : expects 1 arguments - 2 provided d:\home\roe\boost_1_33_1\boost\lambda\detail\bind_functions.hpp(49) : see declaration of 'boost::lambda::bind'

2 3

[Review] Shmem library review results
by Fred Bertsch 17 Feb '06

17 Feb '06

Hello everyone, The formal review of Ion Gaztañaga's Shmem library ended yesterday. I am pleased to announce that it was accepted into Boost! This library clearly generated a lot of interest from people since we got quite a few reviews. All of them were positive. During the discussion, some weaknesses in the library were found, and Ion has agreed to correct them. These include: - Improvements to the documentation and example code. - Clearer documentation on which header files to include for which objects. - Removing the 2-phase construction mechanism and replacing them with RAII-only constructors. - Adding !is_polymorphic static asserts when inserting an object into shared memory. Several difficult issues were raised during the review that will not be solved immediately. These include: - Security information about the shared memory object is currently avoided. - The synchronization objects have some weaknesses. Some of these weaknesses are related to the same weaknesses in Boost.Threads. - Memory mapped file regions are not separate from memory mapped files in the current implementation. - Multi-segment shared memory that would allow the shared memory object to grow. Perhaps these issues could be dealt with in a future version. Thank you, everyone, for the reviews and discussions about Shmem. This library should be extremely useful to those doing IPC. -Fred Bertsch

1 0

Re: [Boost-users] [serialization] Really strange error that crashes the application
by Scott 17 Feb '06

17 Feb '06

> My guess is that the DLL is getting unloaded "too soon". You > might put a break point in the unload code of the DLL and see > if that trips before the assertion. There have been problems > with code explictly unloaded while the type is still "in use" > in a non-obvious way. > > Robert Ramey I'm really at a loss as to why this is happening. Here's the call stack: NwNetworkD.dll!_onexit(int (void)* func=0x0012fa94) Line 81 + 0x2e C ffffffff() boost_serialization-vc71-mt-gd-1_33_1.dll!0032aa2e() NwNetworkD.dll!boost::archive::detail::interface_oarchive<boost::archive::te xt_oarchive>::operator<<<nw::Manager::ManagerNode const >(const nw::Manager::ManagerNode & t={...}) Line 78 + 0x4a C++ NwNetworkD.dll!nw::Manager::save(const std::basic_string<char,std::char_traits<char>,std::allocator<char> > & filename={...}) Line 236 C++ After calling my method "save", it walks a map and serializes my ManagerNode classes. As you can see from the call stack, it then enters a function in the serialization DLL. >From there, something goes horribly wrong. What is ffffffff()? It seems like a bad pointer is getting dereferenced or something. Then the very next action is NwNetworkD.dll!_onexit(). I can tell you that our code is NOT unloading that DLL. At the current time, our code is single threaded and the DLL in question is not actually dynamically loaded/unloaded ever. It's statically loaded by the runtime on application start (we just link against the .lib for that DLL). Scott

1 0

[BGL]johnson_all_pairs_shortest_path algorithm doesn't use distance_inf named parameter.
by Peter Gerell 17 Feb '06

17 Feb '06

Hi, I am had sime difficulties using the johnson_all_pairs_shortest_path algorithm. I have a custom weight type called CostType. I tried calling the algorithm as follows. johnson_all_pairs_shortest_paths(g, D, distance_inf(CostType::infinity())); The result was a distance matrix with all zeros. The problem is the following lines from johnson_all_pairs_shortest_path.hpp DT inf = (std::numeric_limits<DT>::max)(); for (tie(v, v_end) = vertices(g2); v != v_end; ++v) d[*v] = inf; If I specialized the numerical-limits class for CostType everything started to work as expected. namespace std { template<> class numeric_limits<CostType> { public: inline static CostType min() throw() { return -CostType::infinity();} inline static CostType max() throw() { return CostType::infinity(); } }; } Even if this is the good way to solve the problem, it doesn't work for what I want to do. I'm trying to calculate the longest paths by redefining distance_inf and distance_compare. Is this a bug or is it something I don't understand? I am using boost 1.33.1 /Peter

1 1

Re: [Boost-users] [Serialization]: bug while serializingastd::string
by RIVASSEAU Jean Noel 17 Feb '06

17 Feb '06

Hello I have tried to open an archive in text mode with no_codecvt attribute, like this: std::ifstream ifs("archive.mob"); boost::archive::text_iarchive ia(ifs, boost::archive::no_codecvt); but it still triggers the bug. I do not think the bug is due to something that is not handled in the stream, since I do not have any special characters or stuff like that (except end lines). Plus, the fact that it crashes at the magical number 512 characters get me to think it is more related to a buffer problem, however, you are the specialist. How can I investigate the code conversion facets used by text archive? I am not familiar at all with locales, or facets, but if you give me some hints about how they are used in the BSL, I may get started. Regards Jean-Noël Ps: everything works fine in XML archive mode, so for my project I have switched to that, but I'd still like to get this bug fixed for the benefits of all... _____ De : boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] De la part de Robert Ramey Envoyé : jeudi 9 février 2006 17:11 À : boost-users(a)lists.boost.org Objet : Re: [Boost-users] [Serialization]: bug while serializingastd::string Sorry I got mixed up with another post. The main difference between strstream and other streams is that strstream doesn't do any code conversion. This is also consistent with the idea that something in the string isn't being handled in the code conversion facet of the the stream in the expected manner. a couple of ideas would be to investicate the code conversion facets used by the text archive. Also look at the no_codecvt attribute on archive open. Robert Ramey "RIVASSEAU Jean Noel" <JN.RIVASSEAU(a)oberthurcs.com> wrote in message news:87F60F7FA02FF749AFB02BD9FCAA6B04CB28D4@naserv31.nanterre.oberthurcs.com... I am assuming you meant : std::ofstream ifs("container.mob"); boost::archive::text_oarchive ia(ofs); oa << MyObject; ofs << std::endl; and not std::ifstream ifs. So if I understand well, this "patch" only adds a newline to the archive at the saving stage. I tried it but it did not help in any way; in fact I cannot see how it could help, since the problem is at the point of the loading of the std::string, not at the end of the load of the whole object. What I mean here is that MyObject is, in my case, a class containing a std::vector of pointers to class containing std::strings. One of these strings is too long, which causes the crash. Maybe what you meant is appending the std::endl after the serialization of the std::string, but this is not possible since at this point I have only access to the archive, not the underlying ofstream : template<class Archive> void serialize(Archive & ar, const MyClass& m, const unsigned int version) { ar & m.a_standard_string; } I do not have access there to the underlying ofstream of the implementation. Note that here, MyObject would contain a std::vector < MyClass * >. And I am serializing directly MyObject which causes the serialization of MyClass later. So, what do you mean? Have you located the bug ? _____ De : boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] De la part de Robert Ramey Envoyé : jeudi 9 février 2006 04:46 À : boost-users(a)lists.boost.org Objet : Re: [Boost-users] [Serialization]: bug while serializing astd:string Untl 1.34 comes out try the following on the output stream std::ifstream ofs("container.mob"); boost::archive::text_oarchive ia(ofs); oa << MyObject; ofs << std::endl; "RIVASSEAU Jean Noel" <JN.RIVASSEAU(a)oberthurcs.com> wrote in message news:87F60F7FA02FF749AFB02BD9FCAA6B04C87411@naserv31.nanterre.oberthurcs.com... I have been able to test with a string stream; the bug does not occur. That is, this code produces the bug: std::ifstream ifs("container.mob"); boost::archive::text_iarchive ia(ifs); ia & MyObject; while the following does not: std::ifstream ifs("container.mob"); std::ostringstream tmp; tmp << ifs.rdbuf(); std::istringstream is(tmp.str()); boost::archive::text_iarchive ia(is); ia & MyObject; a) try using a different stream buffer - strstream So do you have any clue, Robert ?? Clearly the problem has to do with buffering somewhere.... Jean-Noël _____ _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users _____ _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

2 1

[lambda] typeid & abstract base class
by Roman Krylov 17 Feb '06

17 Feb '06

Hi all. I want to make function comparing two typeid's 'const T&'s , but in context I have only two T* pointers. T is abstract class having pure virtual functions. typeid operator takes reference, not pointer. If I use * operator on placeholder (ll_typeid(*_1)==ll_typeid(*_2)) - compiler complains that it could not instantiate T somewhere in some complex template. I also tried to use ll_static_cast in expression, but it didn't help. I don't attach those error messages, but anyway why should T be instantiated to construct L-expression with *(T*)? By the way I made simple functor and it works the way I want, but it's 6 lines long instead of one in_place expr. : > template<typename T> > struct compareRefsByTypeID > { > bool operator()(const T* t1, const T* t2) > { return typeid((const T&)(*t1))==typeid((const T&)(*t2)); } > }; regards, Roman.

2 1

[ptr_container]Bug in ptr_map::erase?
by Bill Buklis 17 Feb '06

17 Feb '06

The following code does not successfully compile: boost::ptr_map<int,int> testmap; testmap.erase(5); The compiler (MSVC 7.1) complains that the identifier "find" is unknown inside the erase function (see below). The class does have a find function as "testmap.find(5)" compiles as expected. I expect it's a mismatch with the embedded classes. Taken directly from associate_ptr_container.hpp: size_type erase( const key_type& x ) // nothrow { BOOST_ASSERT( !this->empty() ); iterator i = find( x ); // ERROR ON THIS LINE if( i == this->end() ) return 0; this->remove( i ); return this->c_private().erase( i.base() ); } The following workaround does work at least, but the above should also, shouldn't it? testmap.erase( testmap.find(5) ); -- Bill Buklis --

2 1

multi_index_container
by Aashit Soni 17 Feb '06

17 Feb '06

Hi all, I am using multi_index_container on MSVC6, WinXP. I ported my existing Hash and order list to multi_index_container. which is working quite expected? a pure vanila hash_index with ordered_index I am facing some problem in fine tuning the hash_index which is slower compared to my previous implementation. I am looking for different ways how can i fine tune the hash_index in multi_index_container? specifically i am yet to discover, How can i set the bucket size for the hash container? How can configure the container for maximum store it can reserve for me in one shot? any other optimization parameter. If any one has some idea. It will be of great help to me. regards, aashit -- A a s h i t

2 5

Re: [Boost-users] linker errors on (regex) on Debian/unstable(gcc-3.4.6)
by Oliver.Kowalke＠infineon.com 17 Feb '06

17 Feb '06

For all how are faced to similar problems: I could solve my problem by downgrading from binutils_2.16.1cvs20060117-1 to binutils_2.15-6 (seams to be a linker-bug). So long, Oliver

1 0