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Re: [Boost-users] A question on overloaded function? Can anyone with kindness help me?
by fmingu 30 Jun '09

30 Jun '09

Oh,I made a mistake. And can I use: bind(&std::pow,constant(-1),bind(&IIPrimemap::size,var(primemapvec))); in the program? where : typedef std::map<int, int> IIPrimemap; IIPrimemap primemapvec; the last two lines are corrected.

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[IOSTREAMS] Forcing a flush on newlines
by David Larsson 30 Jun '09

30 Jun '09

Hi! I'm outputting the progress from an externally executed command line application using the windows API call OutputDebugString. This means that I need to convert all line breaking characters to flush commands to make sure the text is outputted when a new line is received rather than when some underlying structure finds it suitable to linebreak. I've created a sink that writes to OutputDebugString and it works great, however unless I manually insert lots of std::endl (or flushing some other way) I won't get any output until the buffer is full. Is it possible to write an iostream filter that forces a flush on newlines or is this something I need to handle before feeding data into my stream? /David

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A question on if_then_else in lambda.Can any one with kindness help me?
by fmingu 30 Jun '09

30 Jun '09

I use Dev-c++, and found a problem: # indcude "boost/lambda/if ............... typedef std::map<int, int> IIPrimemap; IIPrimemap primemapvec; ....................... int nnumber; int switchvalue; ........................ if_then_else(var(nnumber)==1,var(switchvalue)=1, if_then_else(count_if(primemapvec.begin(),primemapvec.end(), bind(&IIPrimemap::value_type::second,_1)>2)>0, var(switchvalue)=2,var(switchvalue)=3)); ........................ But the complier told me that: no matching function for call to `if_then_else(bool, const boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::other_action<boost::lambda::assignment_action>, I do not know how to handle it. Can any one with knidness help me?

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test
by Sergey Skorokhodov 29 Jun '09

29 Jun '09

sorry

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[lambda] shared_ptr's in lambda expressions
by Michael Crawford 29 Jun '09

29 Jun '09

I have the following piece of code: void MultiLog::removeLog(const std::string& name) { std::remove_if(m_logs.begin( ), m_logs.end( ), (boost::lambda::_1 ->* &Log::getName) == name); } Which fails to compile with the typical spectacular list of template error messages, the first of which is "error C2784 ... could not deduce template argument for 'const boost::lambda::lambda_functor<T> &' from 'boost::lambda::detail::member_pointer_caller<RET,A,B>'" I'm assuming that the error is because each element here is a shared_ptr<Log>, rather than a raw pointer to Log. Using bind to wrap shared_ptr::get appears to work: void MultiLog::removeLog(const std::string& name) { std::remove_if(m_logs.begin( ), m_logs.end( ), boost::bind(&Log::getName, boost::bind(&LogPtr::get, _1)) == name); } but is there are way to use the significantly cleaner & clearer member pointer operator syntax while using shared_ptr's? Thanks, MBC

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Spirit error when building serialization
by Pascal Kesseli 29 Jun '09

29 Jun '09

Hi again Running bjam with an mxscaleb-gcc cross compilation toolchain (Version 3.4.3), I repeatedly get the following error line on boost spirit: In file included from ./boost/spirit/home/classic/core.hpp:33, from ./boost/spirit/include/classic_core.hpp:11, from ./boost/graph/detail/read_graphviz_spirit.hpp:32, from ./boost/graph/graphviz.hpp:780, from libs/graph/src/read_graphviz_spirit.cpp:28: ./boost/spirit/home/classic/core/primitives/numerics.hpp:124: Error: Declaration »template<class ScannerT> struct boost::spirit::classic::sign_parser::resultÂ« ./boost/spirit/home/classic/core/parser.hpp:125: conflicts with previous declaration of <class ScannerT> struct boost::spirit::classic::parser<boost::spirit::classic::sign_parser>::resultÂ « As a result, building the serialization library fails. Any ideas on how to fix this here? Thanks in advance and greets Kessi

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Re: [Boost-users] Newbie needs yet more help with serialization-BOOST_SERIALIZATION_SPLIT_FREE
by Adam Szeliga 29 Jun '09

29 Jun '09

On 2007-08-20 11:03, Hector C. wrote: You need include file: #include <boost/serialization/split_free.hpp> Regards Adam

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mpl / preprocessor question
by Zachary Turner 29 Jun '09

29 Jun '09

Is there a way, using some combination of boost preprocessor and mpl, that I can write a class template<class T, int n> class foo { public: void foo(T arg1, T arg2, ..., T argn); }; In other words, generate a function that requires n arguments where n is a template parameter?

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boost.fusion compile error using VC 8: error C2039: 'tag_of' : is not a member of 'boost::fusion::traits::detail'
by Tang Jiangjun 29 Jun '09

29 Jun '09

When I compiled the code snippet as follows, there were some errors about searching tag_of in namespace boost::fusion::traits::detail. But after reviewing the source code, I found the desired tag_of was actually located in namespace boost::fusion::detail. Moreover it will be compiled successfully if adding this full and correct namespace before tag_of in the file <is_sequence.hpp>. Here is code snippet: typedef fusion::vector< int, string > TPerson; TPerson person( 20, "Alan" ); cout << person << endl; Here are compile errors: 1>d:\libraries\boost_1_39_0\boost\fusion\support\is_sequence.hpp(59) : error C2039: 'tag_of' : is not a member of 'boost::fusion::traits::detail' 1> d:\libraries\boost_1_39_0\boost\utility\enable_if.hpp(36) : see reference to class template instantiation 'boost::fusion::traits::is_sequence<T>' being compiled 1> with 1> [ 1> T=TPerson 1> ] 1> d:\samples\boost\fusion\fusion.cpp(28) : see reference to class template instantiation 'boost::enable_if<Cond,T>' being compiled 1> with 1> [ 1> Cond=boost::fusion::traits::is_sequence<TPerson>, 1> T=std::ostream & 1> ] Here is the origin code in <is_sequence.hpp>: namespace traits { template <typename T> struct is_sequence : extension::is_sequence_impl<typename detail::tag_of<T>::type>:: template apply<T> {}; } Here is the modification: namespace traits { template <typename T> struct is_sequence : extension::is_sequence_impl<typename boost::fusion::detail::tag_of<T>::type>:: template apply<T> {}; } I guess this should be a minor bug in boost.fusion.

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Threaded Daemon - boost::mutex::lock(): Assertion `!pthread_mutex_lock(&m)' failed.
by John D 28 Jun '09

28 Jun '09

Hi This seems an interesting error. I have an application that when executed as ./execute runs just as fine as can be. However when run with a a daemon that loads on boot, when activated it immediately crashes with. /usr/include/boost/thread/pthread/mutex.hpp:50: void boost::mutex::lock(): Assertion `!pthread_mutex_lock(&m)' failed. The cause of the problem clearly is the lack of an in your face shell which I know and is fine. I am wondering what advice anyone might have for having a stable boost threaded tty less executable that will run. I know it is something very small to change likely in the call to execute the application but please any help is appreciated, Thank you, John D

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