March 2009 - Boost-users - lists.preview.boost.org

[Intrusive] augmenting red black trees
by George Slavov 30 Mar '09

30 Mar '09

I want to know if it's possible to augment the red black tree structure offered by Boost.Intrusive. Specifically I need each node to contain some information like the max value of the subtree rooted at that node and this information should be updated during insert/delete operations. This is a fairly common thing, allowing you to do logarithmic queries that are specific to certain trees, so I'm surprised I couldn't find anything about it in the Boost.Intrusive docs. Regards, George Slavov

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Thread local storage
by Oliver Abert 30 Mar '09

30 Mar '09

Hi Everyone, I am using Boost Threads (1.38) as threading library and I also use the thread_specific_ptr to store a minor amount of data per thread (I think currently it is like 5 different pointer values per thread). Technically everything works out fine, but I am having a performance problem on Mac OS X. On Linux the performance is 10 times faster than on Mac OS. If I use pthreads on Mac OS I have identical performance to the Linux version. Both versions are running on the same machine using 8 threads both. Is there any known problem with shared pointers on Mac OS? I have tried different versions of boost, compiled it myself and also used macports - every time same results on Mac OS. Any hit or possible workaround is very welcome :) Thanks and regards, Oliver

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Re: [Boost-users] Using boost regex dll in code
by dhruva 30 Mar '09

30 Mar '09

Header files corresponding to regex and the dependencies if any (can be found through bcp) -dhruva ________________________________ From: "Green, Jason M NSWCDL, W33" <jason.m.green3(a)navy.mil> To: boost-users(a)lists.boost.org Sent: Monday, 30 March, 2009 6:12:41 PM Subject: [Boost-users] Using boost regex dll in code If I have the boost_regex 1_38 dll and lib for VC 8, what steps do I need to take in order to use it in my code? Is there anything else that I need other than one of those? Jason Unlimited freedom, unlimited storage. Get it now, on http://help.yahoo.com/l/in/yahoo/mail/yahoomail/tools/tools-08.html/

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Using boost regex dll in code
by Green, Jason M NSWCDL, W33 30 Mar '09

30 Mar '09

If I have the boost_regex 1_38 dll and lib for VC 8, what steps do I need to take in order to use it in my code? Is there anything else that I need other than one of those? Jason

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[asio] skipping data in tcp stream
by Roman Shmelev 30 Mar '09

30 Mar '09

HI! What we have: tcp connection, from which we read messages. each message = header(fixed len) + body(random len) header contains the length of body and crc to check if the header is not corrupted. Reading is done in two async steps - first the header is read, then memory for body is allocated and the body is read. Questions are: 1) if header is corrupted under some cases (header crc says body len could be wrong) then as I understand we must skip all body data and read the next message. How to skip? async_read_until seemed to be the solution, but manual told that it may read surplus data into streambuf - it will be hard to deal with that data because I am reading directly from socket to some allocated memory (as was told above) 2) actually, can it be that in tcp stream data will be corrupted? I guess, yes - so header contains bodylen and crc for body and for header? is such solution an overhead? 3) maybe I do some global design mistakes? Thank you!

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String processing algorithms
by Aggelidis Nikos 30 Mar '09

30 Mar '09

hi to all,i am interested in implementing some string processing algorithms{eg boyer-moore , knuth morris prat} for educational purposes. This is the first "real" exposure i will have with boost. I've done a bit of searching and i think Xpressive is the corresponding library of boost, for string processing. From what i read Xpressive is a header-only template library, so i will have to study xpressive.hpp . Any other directions i should follow? thanks in advance for your trouble, nicolas

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[boost][system] Linking problems with C++0x, boost 1.38, Intel C++ 11.0 on windows
by Jesse Perla 30 Mar '09

30 Mar '09

Just to see if it was possible and if I could use "auto", I tried to compile my program with /Qstd:C++0x on Intel Windows 11.0. I am using boost::filesystem (which I assume uses boost::system). I did not recompile these binaries with this flag turned on (partially because I don't know how to mess with bjam or if I needed to mess with settings). The only thing that appears to be failing is linking to boost system. I get the following unresolved externals: 1>sandbox.obj : error LNK2019: unresolved external symbol "class boost::system::error_category const & __cdecl boost::system::get_system_category(void)" (?get_system_category@system @boost@@YAABVerror_category@12@XZ) referenced in function ___sti__$E 1>sandbox.obj : error LNK2019: unresolved external symbol "class boost::system::error_category const & __cdecl boost::system::get_generic_category(void)" (?get_generic_category@system @boost@@YAABVerror_category@12@XZ) referenced in function ___sti__$E I thought maybe automatic linking was buggy, so I tried to add the following to linker inputs, but no luck: libboost_system-iw-mt-gd-1_38.lib Any ideas? Thanks, -Jesse

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[boost] Any experiences with C++0x features with Intel C++ 11.0 on windows and boost?
by Jesse Perla 29 Mar '09

29 Mar '09

Has anyone tried messing around with the /Qstd:C++0x setting on Intel C++ 11.0 and used boost in the same project? I would love to use "auto" and simple "decltype" if possible, but I don't want to waste a bunch of time if this isn't likely to work with boost or is known to cause incomprehensible errors when mixed with older style generic programming. What about really simple use of the new lambdas? In practice, do you think this is premature and likely to cause major regressions in the future? I can't see how "auto" or "decltype" would change, but is simple lambda usage fairly stable in the converging C++0x specs? -Jesse

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[parameter]Boost Parameter and template template arguments
by Jesse Perla 29 Mar '09

29 Mar '09

I have a class template with a large number of potential template parameters where I would like to use boost parameter. I understand that I can use integers with the int_<> wrapper, but is there any trick or design pattern to allow template template's? The problem is that I have class templates such as an interpolator which will take in a type and a dimension size, and a variety of function objects of the same type. If I can't use template templates, I am not sure how to make the design sane. For example, right now I have something like: template<int Dimension, class T = double, template <int Dim2, class T> template Interpolator = cubic_spline> class DPP; I don't think I can write a free function to solve the instantiation difficulty since many of the types are only used internally and I couldn't use function template argument deduction. -Jesse

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Boost.lamba compile errror....
by Joost Kraaijeveld 29 Mar '09

29 Mar '09

Hi, I want to sort a Matrix of Vectors according to their difference in length to some arbitrary Vector. e.g: template< typename T> struct MatrixVector : std::vector< T > { ... double length() const; MatrixVector<T> difference(const MatrixVector< T>& rhs) const; ... } template< typename T > MatrixVector< T > operator-(const MatrixVector< T >& lhs, const MatrixVector< T >& rhs) { return lhs.difference(rhs); } typedef MatrixVector< double > Vector; typedef std::vector< Vector > Matrix; ... Matrix matrix; matrix.push_back(some vectors); // multiple! std::sort( matrix.begin(), matrix.end(), boost::lambda::bind(&Vector::difference, boost::lambda::_1, observation).length() < boost::lambda::bind(&Vector::difference, boost::lambda::_2, observation).length() ); Compiling this gives (GCC 4.3.2, Debian Lenny, Boost 1.35): g++ -DHAVE_CONFIG_H -I. -I../../src -I/usr/include -g -O2 -MT Main.o -MD -MP -MF .deps/Main.Tpo -c -o Main.o ../../src/Main.cpp ../../src/Main.cpp: In function ‘int main(int, char**)’: ../../src/Main.cpp:101: error: ‘const class boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::action<3, boost::lambda::function_action<3, boost::lambda::detail::unspecified> >, boost::tuples::tuple<MatrixVector<double> (MatrixVector<double>::* const)(const MatrixVector<double>&)const, const boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, const MatrixVector<double>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> > >’ has no member named ‘length’ The error "has no member named ‘length’" is unexpected: a MatrixVector , the return value of the global operator is a MatrixVector, has a member length() . I have tried several syntax possibilities but with no luck. Does anyone has any suggestions? TIA -- Groeten, Joost Kraaijeveld Askesis B.V. Molukkenstraat 14 6524NB Nijmegen tel: 024-3888063 / 06-51855277 fax: 024-3608416 web: www.askesis.nl

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