February 2009 - Boost-users

[bccl] Compilation fails due to BOOST_CONCEPT_ASSERT
by Adam Badura 17 Feb '09

17 Feb '09

In my project I have two header files both introducing four BOOST_CONCEPT_ASSERT macros at namespace level. It happened that both those files used those macros at the same lines (same line numbers). The compilation of the one which is included as second fails (on MSVC 2008) with error: d:\studies\thesis\project\prover\formulas\terms\variable.h(83) : error C2365: 'boost_concept_check83' : redefinition; previous definition was 'enumerator' d:\studies\thesis\project\prover\formulas\terms\constant.h (83) : see declaration of 'boost_concept_check83' (repeated for each o those four uses with indexes 84, 85, 86 - clearly line numbers). It seems the line number is used to build some inner use name. Reasonable. But failable as well. Maybe file name macro could be used here however this could give string inappropriate for the identifier. I don't know how to solve this (a temporal workaround is obviously easy - just move the macros in on of files to a different place). I haven't found any info on that neither in the documentation nor in the groups. Adam Badura

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unzip iterator?
by Neal Becker 17 Feb '09

17 Feb '09

I use an iterator adapator that converts a pair of scalar iterators into a complex iterator. But how to go the other direction? Take a complex iterator to a pair of scalar iterators. This is something like 'unzip'. Any thoughts?

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Re: [Boost-users] boost geometry lib
by Barend Gehrels 17 Feb '09

17 Feb '09

Hi, Sorry for my late reply, was not on this list earlier. Thanks for your interest. As Bruno said we're currently busy with preview 4. There are substantial changes internally, but from user perspective the changes are not so large. Two things I'll mention: 1) > > http://geometrylibrary.geodan.nl/6__transformation__example_8cpp-exampl > > e.html > > shows the geometry library and uBLAS working together The transformation example will be changed (and much more simpler, from user perspective). The new version has internally transformation capacities and strategies can be used to finetune this (still using uBLAS) 2) if you plan to use the linestrings, note that the algorithms currently take line.begin() and line.end(). This is changed in the new version to just "line", using the boost range library. Preview 4 is expected this month or the beginning of February. Barend Gehrels Geodan, Amsterdam

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Problem compiling a statemachine with "class" instead of "struct"
by Rudolf Leitgeb 17 Feb '09

17 Feb '09

Hi folks, we have run into an interesting problem when compiling one of our state machines using the boost state chart templates. If we instantiate a state like this: struct Active : public boost::statechart::simple_state< Active, PRX5StateMachine > { public: Active() : m_data("") {} ~Active() {} std::string & Data() { return m_data;} const std::string& Data() const { return m_data; } private: std::string m_data; }; and use it in our code, everything compiles fine. As soon as we change the declaration to class Active : public boost::statechart::simple_state< Active, PRX5StateMachine > we get massive compiler errors, which look like this: /usr/include/boost/statechart/simple_state.hpp:832: error: within this context /usr/include/boost/statechart/state_machine.hpp:243: error: ‘typedef struct boost::statechart::detail::rtti_policy boost::statechart::state_machine<PRX5StateMachine, Active, std::allocator<void>, boost::statechart::null_exception_translator>::rtti_policy_type’ is inaccessible Is it mandatory to inherit from simple_state via a struct and not from a class? Thanks for any inputs on this. On request I post two source directories which show the problem. Cheers, Rudi

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[Interprocess] shared_ptr in shared memory and inheritance
by Gaetan Gaumer 17 Feb '09

17 Feb '09

Hello, we would like to store collections of differents objects derived from a same base class in a shared memory segment, and use polymorphism to manipulate them using shared_ptr<base>. But as we can't have virtual functions in shared memory we are exploring this solution : We designed 2 parallels hierarchies of classes - A hierarchy of empty objects in process memory with virtual functions (polymorphism) (ex : class A) - A hierarchy of data objects in shared memory without virtual functions (class A_data) A "process memory" object stores a weak_ptr to the "shared memory" data object. Use of data are encapsuled in accessors which take care of weak_ptr locking and concurrent access. I don't know if this is a good design (any opinions ?) but it seems to work well... until the destruction of "shared memory" objects. The wrong destructor is used (the base one) instead of the destructor of the derived class, probably because the destructor is not virtual... So I'm currently stuck and I'm looking for some advices. Here is a little code demonstrating the problem : #include <boost/interprocess/managed_shared_memory.hpp> #include <boost/interprocess/smart_ptr/shared_ptr.hpp> #include <iostream> using namespace boost::interprocess; using namespace std; class base { protected : int id; public: base(int i=0):id(i){}; ~base(){cout << "base dtor" << endl;} int getId() const {return id;} }; class derived : public base { protected: double data; public: derived(int i=0, double d=0): base(i), data(d){}; ~derived(){cout << "derived dtor" << endl;} double getData(){return data;} }; typedef managed_shared_ptr<base, fixed_managed_shared_memory>::type base_shared_ptr; int main (){ fixed_managed_shared_memory segment(open_or_create,"sharedPtrSharedMemoryTest", 2048); // does not compile but that's what I would like //base_shared_ptr baseSP = make_managed_shared_ptr(segment.construct<derived>(anonymous_instance)(2,3.0), segment); // turnaround base_shared_ptr baseSP = make_managed_shared_ptr((base*)segment.construct<derived>(anonymous_instance)(2,3.0), segment); cout << "baseSP->getId() =" << baseSP->getId(); cout <<", baseSP->getData() = " << static_pointer_cast<derived>(baseSP)->getData() << endl; baseSP.reset(); // don't know why but base dtor is called 3 times !!! } I can live with static_pointer_cast<> because they'll be hidden in accessors. But I really need that the right destructor (here ~derived()) will be called as it's cause some asserts in real case : include/boost/interprocess/detail/segment_manager_helper.hpp:176: static boost::interprocess::detail::block_header* boost::interprocess::detail::block_header::block_header_from_value(const void*, size_t, size_t): Assertion `hdr->m_value_alignment == algn' failed. The commented call to make_managed_shared_ptr makes gcc complains with (thanks gfilt for formatting) : sharedPtrSharedMemoryTest.cc:30: error: conversion from `boost::interprocess::shared_ptr< derived , boost::interprocess::allocator< void , boost::interprocess::segment_manager< char , boost::interprocess::rbtree_best_fit< boost::interprocess::mutex_family, void *, 0u >, boost::interprocess::iset_index > >, boost::interprocess::deleter< derived , boost::interprocess::segment_manager< char , boost::interprocess::rbtree_best_fit< boost::interprocess::mutex_family, void *, 0u >, boost::interprocess::iset_index > > >' to non-scalar type `boost::interprocess::shared_ptr< base , boost::interprocess::allocator< void , boost::interprocess::segment_manager< char , boost::interprocess::rbtree_best_fit< boost::interprocess::mutex_family, void *, 0u >, boost::interprocess::iset_index > >, boost::interprocess::deleter< base , boost::interprocess::segment_manager< char , boost::interprocess::rbtree_best_fit< boost::interprocess::mutex_family, void *, 0u >, boost::interprocess::iset_index > > >' requested Any help will be welcome. Gaetan

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uBlas: compiler error (Borland 2007)
by Hendrik Fuß 17 Feb '09

17 Feb '09

Hi folks, I'm trying my luck with the Boost.uBlas library, but I'm running into problems. This little snippet: #include <boost/numeric/ublas/matrix.hpp> using namespace boost::numeric::ublas; int main(int argc, char* argv[]) { identity_matrix<double> i(3); matrix<double> m(i); return 0; } should compile alright, shouldn't it? The compiler says: [BCC32 Error] matrix.hpp(2671): E2247 'identity_matrix<double,std::allocator<double> >::one_' is not accessible The same happens if I use the assignment operator instead of copy construction. Can anyone help me? As you've probably seen from the error message, I'm using the CodeGear (alias Borland) 2007 compiler. I'm using a BoostPro 1.37.0 installation. I haven't tried boost 1.38, but the change log doesn't explicitly state any uBlas-related changes. thanks Hendrik

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C1001 ice with date/time and Boost 1.38
by gast128 17 Feb '09

17 Feb '09

Dear all, I just downloaded Boost 1.38 and got ice with VStudio 2003 and sp1: c:\Work Sdk\boost_1_38_0\boost\date_time\gregorian\conversion.hpp(43) : fatal error C1001: INTERNAL COMPILER ERROR (compiler file 'msc1.cpp', line 2708) Please choose the Technical Support command on the Visual C++ Help menu, or open the Technical Support help file for more information It took me 3 hours to solve but it seems that if the /FR (Include All Browse Information) is on, this error is generated. Maybe this helps other people. Sometimes one get aggressive feelings about those boys from Redmond... wkr, me

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[serialization]const member when using boost serialization
by Ray Zhang 17 Feb '09

17 Feb '09

Hi, I got a problem when i use boost:: serialization lib --- whether a const data member could be serialized? For example, class A { const int a; } how can i serialize 'a' by using boost? Best Regards. Ray Zhang. Tsinghua Univ. P.R.China

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[boost-users][bind]
by Igor R 17 Feb '09

17 Feb '09

Hello, Could you please explain what causes the following warning and how to avoid it (boost 1.36, MSVC9.0SP1): typedef boost::weak_ptr<Task> TaskWeakPtr; typedef std::vector<TaskWeakPtr> TaskWeakPtrs; TaskWeakPtrs tasks_; TaskWeakPtrs::iterator toRemove = std::remove_if(tasks_.begin(), tasks_.end(), !boost::bind(&TaskWeakPtr::lock, _1)); 1>../boost\boost/bind.hpp(1643) : warning C4180: qualifier applied to function type has no meaning; ignored 1> ../boost\boost/bind.hpp(1677) : see reference to class template instantiation 'boost::_bi::add_cref<Pm,I>' being compiled 1> with 1> [ 1> Pm=boost::shared_ptr<Task> (__thiscall boost::weak_ptr<Task>::* )(void), 1> I=1 1> ] 1> .\TaskMaker.cpp(90) : see reference to class template instantiation 'boost::_bi::dm_result<Pm,A1>' being compiled 1> with 1> [ 1> Pm=boost::shared_ptr<Task> (__thiscall boost::weak_ptr<Task>::* )(void), 1> A1=boost::arg<1> 1> ] Thank you!

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[boost.propertymap] queries
by Sean Farrow 17 Feb '09

17 Feb '09

Hi: I have two queries about boost.Property map: 1. I am in the middle of writing a class, and have an array with strings in. I would like to be able to have a series of properties in the class, and have these retrieved from different indexes of the array, so for example Comments [array index 1]. Is this possible with boost.Property Map 2 if the answer is yes to the first question, how would this be achieved? Any help appreciated Cheers Sean.

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