- Boost - lists.boost.org

Re: [boost] [optional] swapping initialized with uninitialized
by Václav Veselý 28 Mar '06

28 Mar '06

Ulrich Eckhardt wrote: > On Friday 10 March 2006 17:14, Vaclav Vesely wrote: > > When two optionals (one initialized and other not) are swaped, then the one > > value in uninitialized optional is constructed and the other one in > > initialized optional is destructed. > > > > IMHO it's not necessary. It should be more effective to swap optional's > > m_storages without any values constructiona and destruction. ... > It could only be done if the object was moveable, i.e. depending on a > type_trait. Looking at the Boost type_traits library, I wonder why this trait > doesn't exist - many things can be sped up using memcpy when is_pod is true, > but even things like vector/string/deque (list/map/set depending on whether > their root node is stored by pointer) can be moved in memory without negative > effects (yes, talking about typical implementations here, not guarantees). I see now. But IMHO is_pod is not satisfactory condition for is_movable. For example the class struct X { X* me; // Can points to the instance }; seems to be POD, but it's not movable. The best implicit implamentation is probably the has_trivial_copy trait. For each other moveble type must be is_movable explicitly specialized. (BTW for compiler writers: compiler support for test a trait on all class members would be very useful for many such traits. And existing compilers with support of has_trivial_copy and similar traits must use this technique internally.) I think it worth it. For example I use optional<string> frequently. If you think that the is_movable trait is good enogh for Boost I would like write it including test and documentation. Regards, Vaclav

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[hash] typo in tutorial
by Joaquín Mª López Muñoz 28 Mar '06

28 Mar '06

the first code snippet of Boost.Hash tutorial reads: std::unordered_multiset<std::vector<int>, boost::hash<int> > set_of_ints; ... I guess it should read: std::unordered_multiset<int, boost::hash<int> > set_of_ints; ... Best regards, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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[release 1.34] merging index.htm and CVS $Date$ feature
by Joaquín Mª López Muñoz 28 Mar '06

28 Mar '06

When merging changes in boost/index.htm from HEAD to RC_1_34_0, seems like there's no way to have both branch and trunk to show *exactly* the same contents, as the CVS $Date$ facility kicks in on every commit thus automatically desynching files when a merge is tried. This $Date$ stuff can be seen at about the end of index.htm: <p>Revised $Date: 2006/03/28 07:01:13 $</p> So, the result (if I'm not wrong) is that you'll always have merge conflicts when synching this file between trunk and branch, or the other way around, no matter how carefully you play with merge ops and merged_to_RC_xx tags. * Is this really so, and it's a (minor) problem we have to live with? * Am I wrong and there's a way to handle the issue? Thank you, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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[website] redesign and content
by David Abrahams 28 Mar '06

28 Mar '06

Has anyone seen http://beta.python.org/ recently? Aside from minor details I think it's a wonderful design. And the content! Unbelievably great promotional material. Just look at some of the subtopics of http://beta.python.org/about. It would be great to have something like that for Boost. -- Dave Abrahams Boost Consulting www.boost-consulting.com

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Re: [boost] argument ignore facility
by Daniel Wallin 28 Mar '06

28 Mar '06

Gennadiy Rozental wrote: > Hi, > > Maybe somebody could point me into right direction. boost::bind allows to > present function of arity N as function of arity M with M<N, by binding some > particular arguments. I need reverse: I need to present function of arity N > as function of arity M with M > N, by ignoring some arguments. > > What is recommended to be used? boost::bind can be invoked with any arity and will ignore arguments that are not used. void f(int); bind(&f, _1)(x,y,z,u); // invokes f(x) -- Daniel Wallin

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New implementation of remove_xxx for vintage compilers
by Peder Holt 28 Mar '06

28 Mar '06

Hi. I have started implementing some of the missing type_traits functionality for vintage compilers using typeof. The following are complete, and seem to work flawlessly on VC 6.5 and 7.0: remove_pointer remove_reference remove_bounds The source is available at: http://groups.yahoo.com/group/boost/files/typeof_vintage.zip The use of typeof in this respect, makes remove_xxx much more flexible. Would it be possible to start using this scheme for compilers without partial template specialization support? #define BOOST_MAX_TYPEOF_SIZE 20 #include <boost/test/minimal.hpp> //Include typeof_define.hpp in all header files where new types are added to typeof. #include <boost/typeof/typeof_define.hpp> #include <complex> #include <boost/type_traits/remove_reference.hpp> #include <boost/type_traits/remove_pointer.hpp> #include <boost/type_traits/remove_bounds.hpp> #include <boost/type_traits/is_same.hpp> template<typename A0> struct X {}; template<typename A0,unsigned int A1> struct Y {}; template<typename A0,typename A1,long A2> struct Z {}; BOOST_TYPEOF_DEFINE_TEMPLATE(X,1,(typename)) BOOST_TYPEOF_DEFINE_TEMPLATE(Y,2,(typename,unsigned int)) BOOST_TYPEOF_DEFINE_TEMPLATE(Z,3,(typename,typename,long)) BOOST_TYPEOF_DEFINE_TEMPLATE(std::complex,1,(typename)) int test_main(int, char*[]) { BOOST_TEST((boost::is_same<X<int>* const[8][9],boost::remove_bounds<X<int>* const[5][8][9]>::type>::value)); BOOST_TEST((boost::is_same<Z<X<double&>,Y<bool[4][7],12324>,0>* const*,boost::remove_pointer<Z<X<double&>,Y<bool[4][7],12324>,0>* const**volatile>::type>::value)); //VC7.1 fails to compile remove_reference. BOOST_TEST((boost::is_same<Y<int,345>** const,boost::remove_reference<Y<int,345>** const&>::type>::value)); typedef BOOST_TYPEOF(5.+std::complex<double>(6,7)) result_type; BOOST_TEST((boost::is_same<result_type,std::complex<double> >::value)); return 0; } -- Peder Holt

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[asio] File AIO(win32) and "Overlapped I/O operation is in progress" error
by Felipe Magno de Almeida 28 Mar '06

28 Mar '06

Hi, I'm implementing file AIO in asio for windows. I've tried to use as much as possible from asio. The problem is that when reading bigger files (more than one megabyte), the queue returns an error: code 997, that is converted to "Overlapped I/O operation is in progress." When that happens, the asio deletes the handler, but the operation is still happening, so GetQueuedCompletionStatus returns one more time for the same overlapped with the completed IO, but the handler is already deleted. This happens in: handler_operation::do_completion_impl (win_iocp_demuxer_service:169) It holds a std::auto_ptr to the handler, but has no access to the error code. So I cant see how to correct this. I think that socket AIO could return this too (specially in ConnectEx, I've seen this in my own "raw AIO" code). I havent finished the file aio yet, when it gets a little better I'll publish here (probably this weekend). Thanks, -- Felipe Magno de Almeida

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c2_functions first submission materials uploaded with cleanups
by Marcus Mendenhall 27 Mar '06

27 Mar '06

After much more useful discussion on the list I have uploaded c2_functions_boost_prelim.20060325b.zip to the file vault. It contains the code for c2_functions (header & source), an html folder with Doxygen documentation, and a white paper describing the theory of this package. Anyone who is interested, look over this and let me know how the group wishes to proceed. It adds a lot to the main documentation page, including use cases. Obviously still preliminary, but at least there is a roadmap now. Marcus Mendenhall

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[program_options] parse_command_line
by David Greene 27 Mar '06

27 Mar '06

Is there a specific reason that parse_command_line has this signature? template<typename charT> basic_parsed_options< charT > parse_command_line(int argc, charT * argv, ^^^^^^^ Should this be charT **? const options_description & , int style = 0, function1< std::pair< std::string, std::string >, const std::string & > ext = ext_parser()); This makes parsing nested options (i.e. --param="some more options") unnecessarily difficult. It would be easier if it looked like this: template<typename Int, typename Buf> basic_parsed_options< charT > parse_command_line(Int argc, Buf argv, const options_description & , int style = 0, function1< std::pair< std::string, std::string >, const std::string & > ext = ext_parser()); This way I can use the boost string algorithms to tokenize the suboption string and pass it into another invocation of parse_command_line. Thoughts? Complaints? Smacks upside the head? -Dave

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interest on a geometry library
by rodolfo＠rodsoft.org 27 Mar '06

27 Mar '06

Hi, is there any interest on a geomery library? It has primitives like point, rectangle, circle, triangle, polygon, and functions that operates on them like intersect, union, test if a point is inside, etc. I have some classes that I've built to use in my projects and would like to get it into boost, for everyone's profit. Sorry if there's already another library trying to get into boost with these characteristics. At least I didn't find it in the sandbox. Regards, Rodolfo Lima _______________________________________________________ Yahoo! Acesso Gr�tis - Internet r�pida e gr�tis. Instale o discador agora! http://br.acesso.yahoo.com

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