May 2014 - Boost-users - lists.preview.boost.org

Boost pool and move constructor
by Bruno Sanches 06 May '14

06 May '14

I am trying to create a object using boost object_pool, but trying to use the move constructor of the desired object, but on Visual 2013, I am always getting: error C2664: 'MyObject::MyObject(const MyObject &)' : cannot convert argument 1 from 'MyObject (__cdecl &)(void)' to 'MyObject &&' The error happens because boost pool construct method always assume a const parameter. Sample code: #include <boost/pool/object_pool.hpp> class MyObject{ public: MyObject(): m_iData(0) { } MyObject(MyObject &&other): m_iData(std::move(other.m_iData)) { other.m_iData = 0; } MyObject(const MyObject &rhs) = delete; MyObject &operator=(const MyObject &rhs) = delete; private: int m_iData;}; int main(int, char**){ boost::object_pool<MyObject> pool; MyObject obj; MyObject *pObj = pool.construct(std::move(obj));} Is there any way to invoke the move constructor using boost::object_pool? Thanks Bruno Sanches ======================== http://www.pontov.com.br

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Sequence of boost::logic::tribools - let indeterminate entries inherit from their neighbours
by Jens Müller 06 May '14

06 May '14

Hi, I have a sequence of tribools and I want element with a indeterminate value to inherit from their neighbours. Does such an algorithm exist already in Boost? If not, do you think it would be a useful addition? BR, Jens

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[range] can't use boost::any_range with RTTI disabled due to boost::polymorphic_downcast
by Adam Romanek 06 May '14

06 May '14

Hi! I'd like to draw your attention to an issue with boost::any_range that prevents it from being used with RTTI disabled. The problem is that boost::any_range indirectly uses boost::polymorphic_downcast which in turn uses dynamic_cast. Note that the dynamic_cast is only used to ensure the requested cast is valid and it's done only in non-release builds. It would be great if the check was simply skipped in RTTI-disabled environments, as it is done in release builds. This would result in loss of safety that boost::polymorphic_downcast provides but the pieces that use it would at least compile in RTTI-disabled environments. Would it be possible to fix this problem? If you wish I could create a ticket for this issue. BTW, there's a typo in the documentation of boost::any_range [1]. It mentions boost::forward_pass_traversal_tag, which does not exist. It should rather be boost::forward_traversal_tag. WBR, Adam Romanek [1] http://www.boost.org/doc/libs/1_55_0/libs/range/doc/html/range/reference/ra…

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Boost support of MinGW
by Kosta Zertsekel 05 May '14

05 May '14

Hi guys, It is said that MinGW is not supported by Boost because it is not fully POSIX compatible: http://www.boost.org/doc/libs/1_55_0/more/getting_started/windows.html#pch Excerpt: "A note to Cygwin and MinGW users If you plan to use your tools from the Windows command prompt, you're in the right place. If you plan to build from the Cygwin bash shell, you're actually running on a POSIX platform and should follow the instructions for getting started on Unix variants. Other command shells, such as MinGW's MSYS, are not supported-they may or may not work." Does it mean that is some program that uses Boost was compiled with MinGW, then it can randomly crash or has some stability issues? Thanks in advace, --- Kosta

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[TypeIndex 3.0] Review Manager's Report
by Niall Douglas 04 May '14

04 May '14

Dear Boost, The second round of peer review of proposed Boost.TypeIndex finished on Wed 30th, and here is the review manager's report. My thanks to the five reviewers who took the time and trouble to submit full reviews, plus to everyone else who commented. Votes regarding acceptance: 4 voted to accept TypeIndex into Boost immediately. 1 voted to accept into Boost with conditions. Overall: I recommend immediate acceptance into Boost. Conditions: 1. No one liked the present boost::typeind namespace, almost anything else would be better. I see the namespace has already changed in the develop branch to boost::typeindex, so I think this is already solved. Other common comments: * More than one reviewer mentioned how they liked the docs. * More than one reviewer expressed a desire for an ability to programmatically parse through type specifier strings. I agree with Antony that that is another library which isn't TypeIndex (something Boost.Spirit based which works directly with mangled symbol string representations, representing them as a partial AST - preferably also with a libclang compatible backend - would be great, but that is a totally different library and TypeIndex 3.x provides extensibility for such an additional function). * More than one reviewer sought some method of preventing link if you mix up incompatible uses of TypeIndex and/or with RTTI. Niall -- Currently unemployed and looking for work in Ireland. Work Portfolio: http://careers.stackoverflow.com/nialldouglas/

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What's wrong with my code?
by Bill David 04 May '14

04 May '14

Hi all, I meet a problem with some code with boost and want to ask for some help here. To the following code: #include <list> using namespace std; #include "boost/function.hpp" #include "boost/foreach.hpp" #include "boost/bind.hpp" using namespace boost; void InsertItemHelper(list<int>& inContainer, list<int>::iterator& ioPosition, const list<int>::value_type& inItem) { ioPosition = inContainer.insert(ioPosition, inItem); } void WorkerFunction(const list<int>& inContainer, boost::function<void(int)> const& inAddItemCallback) { BOOST_FOREACH(auto item, inContainer) { inAddItemCallback(item); } } void Print(const list<int>& inContainer) { BOOST_FOREACH(auto item, inContainer) { std::cout << item << endl; } } int main() { list<int> sourceContainer; sourceContainer.push_back(1); sourceContainer.push_back(2); sourceContainer.push_back(3); list<int> targetContainer; list<int>::iterator pos = targetContainer.end(); boost::function<void(int)> addItemCallbackFxn(boost::bind(& InsertItemHelper, targetContainer, pos, _1)); WorkerFunction(sourceContainer, addItemCallbackFxn); return 0; } When I run it on Windows with VS2012, I always get a “list insert iterator outside range” error with: inContainer.insert(ioPosition, inItem); It seems targetContainer I passed to boost::bind is copied so that the following debug error of STL is hit: #if _HAS_ITERATOR_DEBUGGING if (_Where._Mycont != this) _DEBUG_ERROR("list insert iterator outside range"); #endif /* _HAS_ITERATOR_DEBUGGING */ But I am passing targetContainer as a reference and after the error, I can correctly get data in it. Does anybody know what’s wrong behind? Thanks, BD

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