February 2008 - Boost-users

Boost file system idiocy
by Patrick Loney 02 Mar '08

02 Mar '08

Can't find how to seek to eof, currently using: fs.seekp( (std::streamoff)boost::filesystem::file_size( SKDO::ArchiveFilePath( keyname ) ) ); please help ****************************************************************************** "This message and any attachments are solely for the intended recipient and may contain confidential and privileged information. If you are not the intended recipient, any disclosure, copying, use, or distribution of the information included in this message and any attachments is prohibited. If you have received this communication in error, please notify us by reply e-mail and immediately and permanently delete this message and any attachments. Thank you." Interactive Transaction Solutions Ltd (2473364 England) Registered Office: Systems House, Station Approach Emsworth PO10 7PW ********************************************************************** Ce message �lectronique contient des informations confidentielles � l'usage unique des destinataires indiqu�s, personnes physiques ou morales. Si vous n'�tes pas le destinataire voulu, toute divulgation, copie, ou diffusion ou toute autre utilisation de ces informations, est interdite. Si vous avez re�u ce message �lectronique par erreur, nous vous remercions d'en avertir son exp�diteur imm�diatement par email et de d�truire ce message ainsi que les �l�ments attach�s. Interactive transaction Solutions SAS- France (RCS Pontoise : 489 397 877) Si�ge social : Parc Saint Christophe, 10, Avenue de l�Entreprise 95865 Cergy-Pontoise Cedex ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________

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Bind + Function + Arguments
by QbProg 01 Mar '08

01 Mar '08

Hello there, I've started using boost function and bind features , and I'd like to find a way to do the following. You can take it as suggestion, if it is not implemented :) I would like to use the bind function on object members in the same way indipendently of the number of arguments. For example: function <void (int , int ) > FunctionOne; function < bool (int ) > FunctionTwo; class Implementor { public: void ImplOne ( int , int ); bool ImplTwo ( int ); }; void test () { Implementor i; FunctionOne = bind ( &Implementor::ImplOne , &i , _1 , _ 2); FunctionTwo = bind (&Implemenetor::ImplTwo, &i , _1); /* I Would be nice to do something like this, with parameter "guessing" */ // FunctionOne = GenericBind ( &Implementor::ImplOne ,&i); // FunctionTwo = GenericBind ( &Implementor::ImplTwo, &i); /* This will greatly remove verbosity! */ /* Actually I do */ #define Bind0(A,B) bind(A,B) #define Bind1(A,B) bind(A,B,_1) #define Bind2(A,B) bind(A,B,_1,_2) ...... FunctionOne = Bind2 ( &Implementor::ImplOne , &i ); FunctionTwo = Bind1 ( &Implementor::ImplTwo , &i); } It would be usefoul to make library callbacks more usable, insteat of writing a long list of arguments each time. It is possible with current implementation? I ask you for any suggestion, Thank you QbProg

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static assert
by Hicham Mouline 01 Mar '08

01 Mar '08

hi, I would like to avoid template instantiations with ContractType whose static functions st1 and st2 return an enum... template <typename ContractType> class C { BOOST_STATIC_ASSERT( !(ContractType::st1()==A && ContractType::st2()==P) ); ... }; Is there a way to make this work?

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BGL: Can bundled properties not be a struct or class name?
by Jean-Olivier Racine 29 Feb '08

29 Feb '08

Good day, I have a graph with bundled properties attached to both the vertices and edges. typedef long int ASElementID; enum ASRelationships { NoRelationship, IsContaining, IsBeside, IsAbove, IsCommentedBy, IsMadeOf }; typedef boost::adjacency_list<boost::vecS, boost::listS, boost::bidirectionalS, ASElementID, ASRelationships> Graph; When using the write_graphviz and writing my property writer, I get the error_property_not_found error. Reading post 18294 (http://thread.gmane.org/gmane.comp.lib.boost.user/18294) I see what I should probably do. My problem is that I cannot give the address of ASElementID since it is an int. Is it a limitation? Do I *have* to use a struct for it to work? Something like: struct IDType {int ID}; Thanks and have a nice weekend! Jean-Olivier

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[boost test] question on exception testing
by Ovanes Markarian 29 Feb '08

29 Feb '08

Hello *, I have a question regarding the tools BOOST_<level>_THROW: Why is it required to specify the exception being thrown? What if I don't know which exception is thrown, but I know that it should be thrown? My use case is: I have a worker class which executes some functionality. I know that the functionality will throw, but I would like to test that my class will remain in the consistent state after the exception was thrown? With BOOST_<level>_THROW(class_inst.execute()) I could spare the try{}catch(...){} block and make other test assertions, but unfortunately it is not possible, due to lacking of this utility. I would propose a throw guard into the lib, which does not produce any assertion, but swallows an exception. My intention is: I have to develop inside of a huge framework. The functionality I am trying to execute will only work on a target hardware. Since I am inside a debugger and not going to test the the executed functionality itself, but check the state of my class I think such a tool might help. With Kind Regards, Ovanes

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Re: [Boost-users] A request for help using the Boost Unit Test Library
by Tim Allison 29 Feb '08

29 Feb '08

> > Message: 2 > Date: Thu, 28 Feb 2008 18:44:34 +0000 (UTC) > From: Gennadiy Rozental <rogeeff(a)gmail.com> > Subject: Re: [Boost-users] A request for help using the Boost Unit > Test Library > To: boost-users(a)lists.boost.org > Message-ID: <loom.20080228T184232-270(a)post.gmane.org> > Content-Type: text/plain; charset=us-ascii > > Tim Allison <tallison <at> meicompany.com> writes: >>> What compiler are u using? Can you post compilation command? These errors > may >>> only mean that you doing something funny during compilation and compiler > do >>> not see BOOST_AUTO_TEST_CASE macro. >> I am using Gnu compiler 4.1.3-29. I have reduced the number of >> switches, so that the actual line used to build is: >> g++ -g -I../lib -I/usr/X11R6/include -I../../../source/ecs/shared >> -DOS_IS_LINUX -c FuserTests.cc > > Where is boost include? Can you generate preprocessed code? Do you see boost > test code? what do u see in place of BOOST_AUTO_TEST_CASE( test1 )? > > Gennadiy > I ran the -E option on the Gnu compiler. Here is what I hope is the relevant output (at the end of the 38K resulting file!): inline test_case* make_test_case( callback0<> const& test_func, const_string tc_name ) { return new test_case( ut_detail::normalize_test_case_name( tc_name ), test_func ); } template<typename UserTestCase> inline test_case* make_test_case( void (UserTestCase::*test_method )(), const_string tc_name, boost::shared_ptr<UserTestCase> const& user_test_case ) { return new test_case( ut_detail::normalize_test_case_name( tc_name ), ut_detail::user_tc_method_invoker<UserTestCase>( user_test_case, test_method ) ); } } } # 1 "/usr/include/boost/test/detail/enable_warnings.hpp" 1 3 4 # 246 "/usr/include/boost/test/unit_test_suite.hpp" 2 3 4 # 20 "/usr/include/boost/test/unit_test.hpp" 2 3 4 # 5 "FuserTests.cc" 2 BOOST_AUTO_TEST_CASE( test1 ) { boost::test_tools::tt_detail::check_impl( (2 == 1), boost::wrap_stringstream().ref() << boost::unit_test::literal_string( "2 == 1", sizeof( "2 == 1" ) - 1 ), boost::unit_test::literal_string( "FuserTests.cc", sizeof( "FuserTests.cc" ) - 1 ), (std::size_t)12, boost::test_tools::tt_detail::CHECK, boost::test_tools::tt_detail::CHECK_PRED, 0 ); } BOOST_AUTO_TEST_CASE( test2 ) { int i = 0; boost::test_tools::tt_detail::check_frwd( boost::test_tools::tt_detail::equal_impl_frwd(), boost::wrap_stringstream().ref() << "", boost::unit_test::literal_string( "FuserTests.cc", sizeof( "FuserTests.cc" ) - 1 ), (std::size_t)23, boost::test_tools::tt_detail::CHECK, boost::test_tools::tt_detail::CHECK_EQUAL , i, "i" , 2, "2" ); boost::test_tools::tt_detail::check_frwd( boost::test_tools::tt_detail::equal_impl_frwd(), boost::wrap_stringstream().ref() << "", boost::unit_test::literal_string( "FuserTests.cc", sizeof( "FuserTests.cc" ) - 1 ), (std::size_t)25, boost::test_tools::tt_detail::CHECK, boost::test_tools::tt_detail::CHECK_EQUAL , i, "i" , 0, "0" ); } Tim

2 1

Filter packages from a device e.g. network
by Hansi 29 Feb '08

29 Feb '08

Hello, I have a question regarding to filter packages from a device. What is the best way (high performance and not to much copies of the data) to filter data. e.g. I need a filter to make packages from a tcp stream. In this case I have first a field with the length of the package. Best regards Hansjörg

1 0

Using bind with function objects
by Olaf Peter 29 Feb '08

29 Feb '08

Hi, this test file doesn't compile, but why? $ LANG=en g++ bind.cpp -o bind && ./bind /usr/include/boost/bind.hpp: In member function 'R boost::_bi::list2<A1, A2>::operator()(boost::_bi::type<R>, F&, A&, long int) [with R = int, F = Foo, A = boost::_bi::list2<const char*&, const int&>, A1 = boost::arg<1> (*)(), A2 = boost::arg<2> (*)()]': /usr/include/boost/bind/bind_template.hpp:89: instantiated from 'typename boost::_bi::result_traits<R, F>::type boost::_bi::bind_t<R, F, L>::operator()(A1&, const A2&) [with A1 = const char*, A2 = int, R = int, F = Foo, L = boost::_bi::list2<boost::arg<1> (*)(), boost::arg<2> (*)()>]' bind.cpp:22: instantiated from here /usr/include/boost/bind.hpp:278: error: void value not ignored as it ought to be Thanks, Olaf

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[Graph] A* with an implicit graph?
by Ian Downes 28 Feb '08

28 Feb '08

I'd like to do shortest path on an implicit graph - i.e. building it as I go, on examining a vertex I'd like to add the adjacent edges before continuing. Is this supported? If so, can someone point me in the right direction? If not, how could I do this in boost? The boost astar algorithm claims to support implicit graphs using a modified version of the boost bfs algorithm (nonconst_bfs.hpp). This modified version didn't exist in my distribution so I followed the comments in a document from the authors (link below) and removed the const requirements for the graph in breadth_first_search.hpp. The example (implicit example from pdf below, pg 12) compiles ok but seg faults when trying to add a vertex (vertex_t v = add_vertex(vert_prop(white_color), g); page 16 of pdf) in the visitor (some adds succeed first). Any ideas? http://www.cs.rpi.edu/~beevek/research/astar_bgl04.pdf thanks Ian

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problem while using lapack binding
by Baris Gokce 28 Feb '08

28 Feb '08

Hello, I have downloaded binding of boost from http://news.tiker.net/dl/software/boost-bindings and copied them under the boost/numeric. In my code, I am using 'gesvd' function of lapack. There is no compilation error, but while linking following undefined reference to '_dgesvd' error occurs: ../../lib/libTemp.a(MatrixOperationsDefault.o): In function `_ZN16MatrixOperations6MO_svdERN5boost7numeric5ublas6matrixIdNS2_15basic_row_majorIjiEENS2_15unbounded_arrayIdSaIdEEEEESA_SA_SA_': /cygdrive/e/workspace3_2/Locomotion/BOUN/Locomotion/src/MatrixOperations.cc:159: undefined reference to `_dgesvd_' ../../lib/libTemp.a(MatrixOperationsDefault.o): In function `_ZN16MatrixOperations6MO_svdERN5boost7numeric5ublas6matrixIdNS2_15basic_row_majorIjiEENS2_15unbounded_arrayIdSaIdEEEEESA_SA_SA_': /cygdrive/c/boost/boost/numeric/ublas/exception.hpp:127: undefined reference to `_dgesvd_' collect2: ld returned 1 exit status make: *** [test.exe] Error 1 Do I have to compile boost with added binding files again? If yes, how? Best Regards...

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