October 2010 - Boost-users - lists.preview.boost.org

[Fusion] How to join more than two sequences
by Clinton Mead 06 Oct '10

06 Oct '10

Hi All I've noticed the function "join" in the boost fusion library. However, it only joins two sequences. Was wondering whether there is (or can be easily made) a function that joins any number of sequences. For example: new_join(make_vector(1,2,3), make_vector(4,5), make_vector(6)) -> is the sequence 1,2,3,4,5,6 AND/OR (pass parameters in a sequence) new_join(make_vector(make_ vector(1,2,3), make_vector(4,5), make_vector(6))) -> is the sequence 1,2,3,4,5,6 I'd prefer both the first and second versions, but even one version would be ok. Thanks, Clinton

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[filesystem] V3 path::replace_extension() spans path components
by Timothy Madden 06 Oct '10

06 Oct '10

Hello It appears that in boost 1.44.0 filesystem V3 path("\Cristina.ADI\Local Settings").replace_extension(".png") just returns "\Cristina.png" instead of "\Cristina.ADI\Local Settings.png" Could this be fixed ? Thank you, Timothy Madden

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[proto]Compile issue on Sun Solaris 10, Sun Studio 12.2
by Sascha Ochsenknecht 06 Oct '10

06 Oct '10

Hello, I got an error from the Sun Studio 12.2 (CC 5.11) when trying to compile my sources. The error comes out of the Boost.Proto library (actually I'm doing something with Boost.Spirit and Boost.Spirit is using Boost.Proto ..., but I don't think that the problem is in the client code, it seems to come from the buggy compiler). I'm using Boost 1.43. This is what I got from the compiler: "...include/boost/proto/detail/decltype.hpp", line 343: Error: Partial specialization parameter V is not used in the arguments. "...include/boost/proto/transform/arg.hpp", line 287: Error: Partial specialization for boost::proto::_byval::result has identical arguments. "...include/boost/proto/extends.hpp", line 600: Error: type is not a member of boost::result_of<boost::proto::domainns_::default_domain>. "...include/boost/spirit/home/support/terminal.hpp", line 237: Where: While specializing "boost::proto::exprns_::extends<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<boost::spirit::tag::bin>, 0>, boost::spirit::terminal<boost::spirit::tag::bin>, boost::proto::domainns_::default_domain, 0>". (the following is talking about "include/boost/proto/detail/decltype.hpp", line 343) With g++ this code compiles without any problems and runs as expected. Searching around the internet, I got the following bug entry of the Sun Studio compiler: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6926895 It looks like a similar problem. The bug entry contains a small example which reproduces the compile error: template <typename T> struct test { T t; }; template <typename T, typename X> struct test<X T::*> { X T::* x; }; template <typename T> struct test2 {}; template <typename T, typename X> struct test2< test<X T::*> > { test<X T::*> xt; }; int main() { test<int> a; a.t = 1; int test<int>::* s = &test<int>::t; test<int test<int>::*> a2; a2.x = s; test2<test<int test<int>::* > > a3; a3.xt = a2; return a.*a3.xt.x; } $ CC example.C "example.C", line 4: Error: Partial specialization parameter T is not used in the arguments. The bug entry also provides a workaround which seems to work. Replace the template types with the following: template <typename T> struct helper { }; template <typename T> struct test2 : public test2< helper<T> > { }; template <typename T> struct test2<helper< T> > { } ; template <typename T, typename X > struct test2< helper<test<X T::* > > {test<X T::*> xt; }; I would like to try a similar workaround adapted to the Boost.Proto source code. I tried several things but since I'm not fully aware what is going on in the proto sources and what is the exact reason the compiler fails, I couldn't make it work so far. Does anybody had a similar problem or does anybody know how to adapt the Boost.Proto source to make the Sun compiler happy? BTW: For me it would be ok for now to patch my local Boost source files. Here is the snippet from proto/detail/decltype.hpp: //////////////////////////////////////////////////////////////////////////////////////////// // result_of_ is a wrapper around boost::result_of that also handles "invocations" of // member object pointers. template<typename T, typename Void = void> struct result_of_ : boost::result_of<T> {}; // THE FOLLOWING IS TROUBLE MAKER FOR THE SUN COMPILER -> template<typename T, typename U, typename V> struct result_of_<T U::*(V), typename enable_if_c<is_member_object_pointer<T U::*>::value>::type> { BOOST_STATIC_CONSTANT(bool, is_V_a_smart_ptr = 2 == sizeof(test_V_is_a_U<U>(&lvalue(make<V>())))); BOOST_STATIC_CONSTANT(bool, is_ptr_to_const = 2 == sizeof(test_ptr_to_const(BOOST_PROTO_GET_POINTER(U, make<V>())))); // If V is not a U, then it is a (smart) pointer and we can always return an lvalue. // Otherwise, we can only return an lvalue if we are given one. typedef typename mpl::eval_if_c< (is_V_a_smart_ptr || is_reference<V>::value) , mpl::eval_if_c< is_ptr_to_const , add_reference<typename add_const<T>::type> , add_reference<T> > , mpl::identity<T> >::type type; }; Thanks in advance, Sascha

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boost 1.44.0 undefined reference to boost::filesystem2::no_check
by Asif Fayyaz 06 Oct '10

06 Oct '10

Hi, I am compiling a very simple application using boost filesystem. However it is giving following error message: "undefined reference to `boost::filesystem2::no_check(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'" Here is the simple application source: --------------------------------Sample application source: #include <stdio.h> #include <boost/filesystem.hpp> int main() { std::string m_FileName(boost::filesystem::path("testfile1.txt", boost::filesystem::no_check).native_file_string()); printf("Testboost.....%s\n", m_FileName.c_str()); return 0; } -------------------------------- More Details: Libraries being used: libboost_filesystem-gcc41-mt-1_44.a libboost_system-gcc41-mt-1_44.a Boost version: 1.44.0 Boost was build using command: bjam --build-type=complete --layout=versioned Operating System: Linux CentOS5.2 Any help in this regard will be appreciated. Asif

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Re: [Boost-users] Users! Who'd like to wave goodbye to #ifdef
by Paul Kerchen 06 Oct '10

06 Oct '10

+1 for removing VC6 support. Paul Kerchen

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Re: [Boost-users] Problems with boost 1.44.0 and MSVC: deque problem seems solved, but the boost::ctor problem remains
by Yana A Kireyonok (aka Iron Bug) 06 Oct '10

06 Oct '10

> Date: Tue, 5 Oct 2010 11:37:35 +0200 > From: Igor R <boost.lists(a)gmail.com> > 2010/10/5 Yana A Kireyonok (aka Iron Bug) <death.iron.bug(a)gmail.com>: >> Greetings, ppl. >> I've got strange problems with the latest stable boost (1.44.0) and >> MSVS studios 2005 and 2010. >> ... > According to your description, it seems that the issue you encountered > is only a symptom of some memory-management issue in your code >..... Well, it could happen if I wasn't a professional programmer (over 15 years of real time systems hardware and software programming). It's not a typical beginners mistake, for sure. I wouldn't bother ppl in here if I hadn't checked all possible variants and wasn't sure it was really something out of order. > Date: Tue, 5 Oct 2010 12:38:02 +0000 > From: David Ward <davidjward30(a)hotmail.com> > >> Greetings, ppl. >> I've got strange problems with the latest stable boost (1.44.0) and >> MSVS studios 2005 and 2010. >> > Hi, > You might want to check out this known bug with std::deque in MSVC. It's due > to be fixed in VC11: > https://connect.microsoft.com/VisualStudio/feedback/details/533131/bug-in-s… > Regards, > David. Yes, this is very possible! I performed some more experiments, encountering the bug issue you mentioned and in my case it seems being the pop_front method that ruins the iterators, despite of using interlocking mechanism. Perhaps, it's the matter of timings: that's why it doesn't trigger when I use other locking methods. But I should uproot using deques in my code, anyway. It may show up again on faster or slower machines. Well, I will be aware of danger of using deques in MSVS. Never liked MS, to say the truth... :) But have to deal with it sometimes. Still, remains the question what to do with constructor of boost::thread in MSVS 2010. It fails with access violation, without any specific conditions, in simple plain piece of code.

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[Fusion] fusion vector transformation into another fusion vector transformation.
by alfC 05 Oct '10

05 Oct '10

I have class that is parameterized by several type (Boost::Unit units type). template<class U1, class U2, ... > class A{ A(quantity<U1> q1, quantity<U2> q2, ... ){} }; since the number of arguments is arbitrary I though it would be a good idea to use either MPL sequence and Tuples. Or better yet a fusion::vector. so the class will be parametrized by a fusion::vector or unit types. template<class FusionOfUnits> //or class MPLofUnits class A{ A(FusionOfQuantities fq){} //or TupleOfUnits }; The questions is: ¿what is the best way to transform a fusion::vector<unit1, unit2, unit3, ..., unitN > into a fusion::vector<quantity<unit1>, quantity<unit2>, quantity<unit3>, ..., quantity<unitN> > whete the N is (compile-time) arbitrary, i.e. the lenght of the fist fusion::vector is arbitrary (If you are not familiar with Boost.Units, unitN is just a type and quantity is a template type.) Thank you, Alfredo

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timezone database discrepancy
by archie14 05 Oct '10

05 Oct '10

I am calculating start/end time of the daylight savings time using tz_database and default timezone database file "date_time_zonespec.csv" that comes with boost 1_44. I found discrepancy between results of the calculation for "America/Chicago" region and published data. for years 2010-2007 the results match. However, for the 2006 calendar year, published results from several sources are: Start: April 2 End: October 29 and calculated results are: Start: March 12 End November 5 I will appreciate any advise/comments on how to deal with this issue.

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Re: [Boost-users] [proto] need explanation in implementing distributive law
by Mauro Bianco 05 Oct '10

05 Oct '10

Hi all, It is probably already been discovered by everyone at this point, but the code proposed by Andrew does not to work properly to apply distributivity more than once in an expression [works for a*(b+c) but not for a*(b+c*(d+c)) ] Here a modified version that seems to work recursively. How does it look? struct distr : proto::or_< proto::when< proto::multiplies< proto::_, proto::plus< proto::_, proto::_ > >, proto::call<distr( // THIS IS TO RECURSE proto::_make_plus( proto::_make_multiplies( proto::_left, proto::_left( proto::_right ) ), proto::_make_multiplies( proto::_left, proto::_right( proto::_right ) ) ) ) > >, proto::otherwise<proto::nary_expr<proto::_, proto::vararg<distr> > > > {}; Regards, Mauro. On 22.03.2010 22:11, Andrew Durward wrote: > As a follow-up, the attached code seems to compile and yield the expected > result. > > andrew > > > > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Serialize a class, call new() in constructor
by Michael Reichlin 05 Oct '10

05 Oct '10

Hi everybody, actually i have a big problem with serializing some of my classes. The problem is, that classA class calls new of classB in constructor and after that the load_construct_data is called and also calls a new of classB. So I have two objects of classB. Here is my code: classA.h: class CClassA { template<class Archive> friend void serialize(Archive &ar, CClassA &cCClassA, const unsigned int version); template<class Archive> friend void save_construct_data(Archive &ar, const CClassA *cCClassA, const unsigned int version); template<class Archive> friend void load_construct_data(Archive &ar, CClassA *cCClassA, const unsigned int version); // *** Aufzählungen **************************************************************************** public: CClassB* pClassB; // *** Methoden ******************************************************************************** private: protected: int iTest; public: CClassA(int iTest); // Konstruktor virtual ~CClassA(); // Destruktor // Get/Set-Methoden }; classA.cpp: CClassA::CClassA(int iTest) :iTest(iTest) { pClassB = new CClassB(iTest); } classB.h: class CClassB { template<class Archive> friend void serialize(Archive &ar, CClassB &cCClassB, const unsigned int version); template<class Archive> friend void save_construct_data(Archive &ar, const CClassB *cCClassB, const unsigned int version); template<class Archive> friend void load_construct_data(Archive &ar, CClassB *cCClassB, const unsigned int version); // *** Aufzählungen **************************************************************************** public: // *** Datenmember ***************************************************************************** private: protected: public: // *** Methoden ******************************************************************************** private: protected: int iTestInt; public: CClassB(int iTest); // Konstruktor virtual ~CClassB(); // Destruktor // Get/Set-Methoden static unsigned int count; }; serialize.h template<class Archive> void serialize(Archive &ar, CClassA &cCClassA, const unsigned int version) { ar & boost::serialization::make_nvp("ClassB", cCClassA.pClassB ); } template<class Archive> void save_construct_data(Archive &ar, const CClassA *cCClassA, const unsigned int version) { ar << boost::serialization::make_nvp("Test", cCClassA->iTest); } template<class Archive> void load_construct_data(Archive &ar, CClassA *cCClassA, const unsigned int version) { int iTest; ar >> boost::serialization::make_nvp("Test", iTest); ::new(cCClassA) CClassA(iTest); } template<class Archive> void serialize(Archive &ar, CClassB &cCClassB, const unsigned int version) { } template<class Archive> void save_construct_data(Archive &ar, const CClassB *cCClassB, const unsigned int version) { ar << boost::serialization::make_nvp("Test", cCClassB->iTestInt); } template<class Archive> void load_construct_data(Archive &ar, CClassB *cCClassB, const unsigned int version) { int iTest; ar >> boost::serialization::make_nvp("Test", iTest); ::new(cCClassB) CClassB(iTest); } Now I just want that only one ClassB will be created. How can I recognize, that ClassB is already generate through cons tructor classA. I just want to serialize the members of classB. Is there a way to solve my problem?? Best regards Michael

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