July 2010 - Boost-users - lists.preview.boost.org

boost::asio::error::eof
by Lloyd 11 Jul '10

11 Jul '10

Hi, I am asynchromously reading from a file. At the file read handler there is an error checking like this- if(error==boost::asio::error::eof) { //do something } else { cout<<error.messge()<<endl; } When the end of file reaches, the control does not enter into the "if portion", instead it enters the else condition and prints the message "Reached the end of the file". Am I comparing error wrongly? or else where could be the problem? How can I know that the end of file has reached? Thanks a lot, Lloyd ______________________________________ Scanned and protected by Email scanner

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asio::async_write, how to delete data after
by Matteo Lanzi 11 Jul '10

11 Jul '10

Hi, I modified a little the echo server example and to build up a simple tcp server; basically what I do is: - Start the server in a thread - When a session is created I start async read - If my session receive a signal I write a data with async write function - Handle data written then start again async read ( otherwise the connection should be closed ) I have some specific functions which prepare packets and then invoke the write method I would like to avoid static allocation of my buffer instead of dynamic one; for doing that I supposed to use shared_array<T> I can't do that because the boost::asio::buffer, required by the write method, doesn't seem to accept smart pointer. So my questions are: - Is there a common pattern to follow for preparing data and delete them after the delivery ? - Is it possible to use smart pointers with async_write ? - Is the async_write executed in another thread ? should I have concurrency problems if I would use an unique output buffer and clear it on the handle_write callback ? Thanks Matteo

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where to find examples
by Abbhishek Misra 11 Jul '10

11 Jul '10

Hello Boost Users, I'm new to boost and have been looking out for good boost usage examples. I'm particularly interested in Concurrent Programing. I could find only following examples . Please let me know where to find rest. http://www.boost.org/doc/libs/1_42_0/doc/html/boost_asio/examples.html regards Abhishek

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[Range] simple (I hope) question
by Kenny Riddile 10 Jul '10

10 Jul '10

Say I have a vector of vectors and I want to sort each "child" vector. How would I accomplish this using range::for_each and range::sort?

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(1.43) unordered_map compile error with Sun CC 12
by Anand Subramanian 10 Jul '10

10 Jul '10

I am getting the following compilation error when using 1.43 version of unordered_map. $ CC -I<BOOST_INCLUDE_DIR> main.cpp -library=stlport4 "<BOOST_INCLUDE_DIR>/boost/unordered/detail/table.hpp", line 38: Error: Could not find a match for boost::unordered_detail::hash_table<boost::unordered_detail::T>::find_iterator<boost::unordered_detail::hash_table<boost::unordered_detail::T>::Key, boost::unordered_detail::hash_table<boost::unordered_detail::T>::Pred>(boost::unordered_detail::T::bucket_ptr, const boost::unordered_detail::Key&, const boost::unordered_detail::Pred&) const. "<BOOST_INCLUDE_DIR>/boost/unordered/detail/table.hpp", line 38: Error: Too many args in template, from boost::unordered_detail::Pred on ignored. "<BOOST_INCLUDE_DIR>/boost/unordered/detail/table.hpp", line 595: Error: Could not find a match for boost::unordered_detail::hash_table<boost::unordered_detail::T>::find(const boost::unordered_detail::Key&, const boost::unordered_detail::Hash&, const boost::unordered_detail::Pred&) const. "<BOOST_INCLUDE_DIR>/boost/unordered/detail/table.hpp", line 595: Error: Too many args in template, from boost::unordered_detail::Hash on ignored. 4 Error(s) detected. $ cat main.cpp #include <boost/unordered_map.hpp> int main() {} The same code compiles using boost 1.38. Is there any idea on what the issue is? -- Anand

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[bjam] boost mpi compiler wrapper
by alfC 10 Jul '10

10 Jul '10

In my system (cluster) there is a mpiCC wrapper for mpi c++ compilation. Unfortunately it is not compatible with bjam detection. so I added the lines: using mpi : mpiCC : <...>... ; to project-config.jam however when trying to compile boost.mpi it still uses g++ so the correct mpi.h file is not detected. I found that if I modifying unsing gcc : : mpiCC : <...> ... ; does the job. So, should I compile the whole boost with mpi compiler wrapper? It doesn't seem elegant and I fear problems in the future for libraries that don't use mpi. Thank you, Alfredo

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[MPI] optimization for homogeneous clusters
by Riccardo Murri 09 Jul '10

09 Jul '10

Hello, The manual for Boost.MPI 1.43.0 states: "More optimizations are possible on homogeneous machines, by avoiding MPI_Pack/MPI_Unpack calls but using direct bitwise copy. This feature can be enabled by defining the macro BOOST_MPI_HOMOGENEOUS when building Boost.MPI and when building the application." What is the correct way of building Boost.MPI for homogeneous systems? Should I just uncomment the relevant line in boost/mpi/config.hpp, or is there another (and recommended) way through Jam files? Thank you very much in advance for any suggestion. Best regards, Riccardo -- Riccardo Murri, Hadlaubstr. 150, 8006 Zürich (CH)

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FW: Linking to static libraries with Bjam
by Pashley, Mark 09 Jul '10

09 Jul '10

Hi, I am trying to build a boost::python library that uses serialization using BJAM. Unfortunately I cannot get the Jamfile to accept any commands to link the static library libboost_serialization.a into my .so file. I can build simple boost::python libraries but now I need to call functions/classes in this library from my python wrapped classes. My basic jamfile looks like this: project-root ; import python ; extension MyLib : MyClass.cpp <template>@boost/libs/python/build/extension : ; I am running CentOs version 5, boost_1_33_1 (unfortunately I cannot upgrade to a later version) bjam, (built from boost-jam-3.1.18) Currently when I run bjam the environment variable $BOOST_BUILD_PATH is not set, because of this I believe that bjam is building as "v1". If I set $ BOOST_BUILD_PATH to ~/boost_1_33_1/tools/build/v2 I can no longer build even simple examples and I am presented with the errors: error: Could not find parent for project at '.' error: Did not find Jamfile or project-root.jam in any parent directory. If I could get bjam to work with "v2" I believe that I could get syntax correct for adding the library to Jamfile. The directory ~/boost_1_33_1/tools/build/v2 contains: site-config.jam which is empty user-config.jam which has the following lines uncommented: import toolset : using ; using gcc ; using python ; Ultimately I would like to be able to build boost python code with make instead of bjam - has anyone managed this, if so is there an example makefile anywhere? Any help would be greatly appreciated. Regards Mark -- Roke Manor Research Ltd, Romsey, Hampshire, SO51 0ZN, United Kingdom A Siemens company Registered in England & Wales at: Siemens plc, Faraday House, Sir William Siemens Square, Frimley, Camberley, GU16 8QD. Registered No: 267550 ------------------------------------------------------------------------ Visit our website at www.roke.co.uk ------------------------------------------------------------------------ The information contained in this e-mail and any attachments is proprietary to Roke Manor Research Ltd and must not be passed to any third party without permission. This communication is for information only and shall not create or change any contractual relationship. ------------------------------------------------------------------------ Please consider the environment before printing this email -- Roke Manor Research Ltd, Romsey, Hampshire, SO51 0ZN, United Kingdom A Siemens company Registered in England & Wales at: Siemens plc, Faraday House, Sir William Siemens Square, Frimley, Camberley, GU16 8QD. Registered No: 267550 ------------------------------------------------------------------------ Visit our website at www.roke.co.uk ------------------------------------------------------------------------ The information contained in this e-mail and any attachments is proprietary to Roke Manor Research Ltd and must not be passed to any third party without permission. This communication is for information only and shall not create or change any contractual relationship. ------------------------------------------------------------------------ Please consider the environment before printing this email

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Testing that a particular operator is not alllowed
by Edward Diener 09 Jul '10

09 Jul '10

Is there any way to test at compile time, using a Boost construct, that a particular operator is not allowable for a given type, other than simply compile the code and have the compiler generate an error message when trying to use an operator on an object of that type ? I am writing some tests for an MPL library on which I am working where I want to make sure that a given operator for my template class instantiation object will fail to compile, but I would like to do this in such a way that I can generate a compile time message for the failure rather than an actual compiler error. I suspect this is not possible but I thought I would ask anyway.

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Please help with metaprogramming question : termination of recursion
by John Dlugosz 09 Jul '10

09 Jul '10

I'm using Fusion to create a list of Range objects. Here is a simple function: using namespace boost::fusion; template <typename STLCollection, typename FusB, typename FusE> void process_append (STLCollection& collection, const FusB& begin, const FusE& end) { std::cout << "Yip! "; typename result_of::deref<FusB>::type r= deref(begin); /*23*/ collection.insert (collection.end(), boost::begin(r), boost::end(r)); typename result_of::next<FusB>::type successor= next(begin); /*25*/ if (successor != end) process_append (collection, successor, end); std::cout << "Yap! "; } I expect it to print Yip! n times and then Yap! n times. What I get is a compiler error concerning the boost::begin(r) or boost::end(r), that I'm calling it on a fusion::void_ rather than a Range. As you see, I have moved the end-of-recusion test from its normal position at the top of the function (test when called, and return immediately rather than doing the normal body) to the point of the recursive call (don't call with the end sentinel). However, this appears to still trigger the function expansion, since the trail of errors seems to go from the point marked 23 as the original (inner-most) error, to several stops at point 25, to the caller, and so on back out. So it expands several times and then errors, so I think it is objecting to the "end" case. Now if simply mentioning the function, not calling it, is enough to make it expand the function, then more levels of indirection isn't going to help. What is the proper way to do this? Is there, somewhere, a proper example of using Fusion to iterate from begin to end of a Fusion collection? Presumably this must be done using recursion because the type of "next(I)" is not necessarily the same as the type of "I". If some other kind of overloading or partial specialization is the trick, I would expect that the "end" type, or the dereference of the "end" type, would be documented as something I could easily use for that. Please help. Thanks in advance, --John 2>D:\boost_1_43_0\boost/range/iterator.hpp(63) : error C2039: 'type' : is not a member of 'boost::mpl::eval_if_c<C,F1,F2>' 2> with 2> [ 2> C=true, 2> F1=boost::range_const_iterator<boost::fusion::void_>, 2> F2=boost::range_mutable_iterator<const boost::fusion::void_> 2> ] 2> blahblahblah.h(23) : see reference to class template instantiation 'boost::range_iterator<C>' being compiled 2> with 2> [ 2> C=const boost::fusion::void_ 2> ] 2> blahblahblah.h(25) : see reference to function template instantiation 'void Aa::catranges_help::process_append<STLCollection,boost::fusion::cons_iterator<const boost::fusion::nil>,FusE>(STLCollection &,const FusB &,const FusE &)' being compiled 2> with 2> [ 2> STLCollection=std::vector<RTPRICEREC>, 2> FusE=boost::fusion::cons_iterator<const boost::fusion::nil>, 2> FusB=boost::fusion::cons_iterator<const boost::fusion::nil> 2> ] 2> blahblahblah.h(25) : see reference to function template instantiation 'void Aa::catranges_help::process_append<STLCollection,boost::fusion::cons_iterator<Cons>,FusE>(STLCollection &,const FusB &,const FusE &)' being compiled 2> with 2> [ 2> STLCollection=std::vector<RTPRICEREC>, 2> Cons=const boost::fusion::cons<std::pair<std::_Vector_const_iterator<RTPRICEREC,std::allocator<RTPRICEREC>>,std::_Vector_const_iterator<RTPRICEREC,std::allocator<RTPRICEREC>>>,boost::fusion::nil>, 2> FusE=boost::fusion::cons_iterator<const boost::fusion::nil>, 2> FusB=boost::fusion::cons_iterator<const boost::fusion::cons<std::pair<std::_Vector_const_iterator<RTPRICEREC,std::allocator<RTPRICEREC>>,std::_Vector_const_iterator<RTPRICEREC,std::allocator<RTPRICEREC>>>,boost::fusion::nil>> 2> ] 2> blahblahblah.h(25) : see reference to function template instantiation 'void Aa::catranges_help::process_append<STLCollection,boost::fusion::cons_iterator<Cons>,FusE>(STLCollection &,const FusB &,const FusE &)' being compiled 2> with 2> [ 2> STLCollection=std::vector<RTPRICEREC>, 2> Cons=const boost::fusion::cons<std::vector<RTPRICEREC>,boost::fusion::cons<std::pair<std::_Vector_const_iterator<RTPRICEREC,std::allocator<RTPRICEREC>>,std::_Vector_const_iterator<RTPRICEREC,std::allocator<RTPRICEREC>>>,boost::fusion::nil>>, 2> FusE=boost::fusion::cons_iterator<const boost::fusion::nil>, 2> FusB=boost::fusion::cons_iterator<const boost::fusion::cons<std::vector<RTPRICEREC>,boost::fusion::cons<std::pair<std::_Vector_const_iterator<RTPRICEREC,std::allocator<RTPRICEREC>>,std::_Vector_const_iterator<RTPRICEREC,std::allocator<RTPRICEREC>>>,boost::fusion::nil>>> 2> ] 2> blahblahblah.h(55) : see reference to function template instantiation 'void Aa::catranges_help::process_append<std::vector<_Ty>,boost::fusion::cons_iterator<Cons>,boost::fusion::cons_iterator<const boost::fusion::nil>>(STLCollection &,const FusB &,const FusE &)' being compiled 2> with 2> [ 2> _Ty=RTPRICEREC, 2> Cons=const boost::fusion::cons<std::pair<std::_Vector_const_iterator<RTPRICEREC,std::allocator<RTPRICEREC>>,std::_Vector_const_iterator<RTPRICEREC,std::allocator<RTPRICEREC>>>,boost::fusion::cons<std::vector<RTPRICEREC>,boost::fusion::cons<std::pair<std::_Vector_const_iterator<RTPRICEREC,std::allocator<RTPRICEREC>>,std::_Vector_const_iterator<RTPRICEREC,std::allocator<RTPRICEREC>>>,boost::fusion::nil>>>, 2> STLCollection=std::vector<RTPRICEREC>, 2> FusB=boost::fusion::cons_iterator<const boost::fusion::cons<std::pair<std::_Vector_const_iterator<RTPRICEREC,std::allocator<RTPRICEREC>>,std::_Vector_const_iterator<RTPRICEREC,std::allocator<RTPRICEREC>>>,boost::fusion::cons<std::vector<RTPRICEREC>,boost::fusion::cons<std::pair<std::_Vector_const_iterator<RTPRICEREC,std::allocator<RTPRICEREC>>,std::_Vector_const_iterator<RTPRICEREC,std::allocator<RTPRICEREC>>>,boost::fusion::nil>>>>, 2> FusE=boost::fusion::cons_iterator<const boost::fusion::nil> 2> ] 2> blahblahblah.h(53) : while compiling class template member function 'Aa::catranges_help::object<R,Tail>::operator std::vector<_Ty>(void) const' 2> with 2> [ 2> R=std::pair<std::_Vector_const_iterator<RTPRICEREC,std::allocator<RTPRICEREC>>,std::_Vector_const_iterator<RTPRICEREC,std::allocator<RTPRICEREC>>>, 2> TradeStation Group, Inc. is a publicly-traded holding company (NASDAQ GS: TRAD) of three operating subsidiaries, TradeStation Securities, Inc. 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