April 2008 - Boost-users - lists.preview.boost.org

Re: [Boost-users] [multi_index] custom template class for handle multi_index map
by JOAQUIN M. LOPEZ MUÑOZ 17 Apr '08

17 Apr '08

________________________________________ De: boost-users-bounces(a)lists.boost.org [boost-users-bounces(a)lists.boost.org] En nombre de damny(a)web.de [damny(a)web.de] Enviado el: jueves, 17 de abril de 2008 21:13 Para: boost-users(a)lists.boost.org Asunto: [Boost-users] [multi_index] custom template class for handlemulti_index map > hi, > > i'm a newbie to boost an templates. > but for my interrest i experimentalise with that. > so i created an example like the following: [... ] > could you explain why the second try of using "getmapelm" results in an error? [...] Hi Daniel, I don't see any blatant mistake, but as your code is not complete and I therefore cannot compile it and run it I'm missing the problem. A shot in the dark: How's your STRING type hashed according to Boost.Hash? Remember that to use a user-defined type with Boost.Hash you have to define an appropriate hash_value overload as described at http://boost.org/doc/libs/1_35_0/doc/html/hash/custom.html If after examining this point your problem persists and you can provide a compilable snippet for me to run I can try to be a little more helpful. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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[thread] Condition::notify_one, wait
by Anteru 17 Apr '08

17 Apr '08

Hiho, I'm using the new Boost Threads for a Thread Pool, however, I've got some weird problems. The documentation of Condition::notify_one says it unblocks one of the threads waiting currently on the condition -- what happens if I have several threads waiting and I call notify_one twice? It seems that on Windows/x64/VC9, only on thread wakes up if notify_one is called twice in a row. Is this right? Second, wait says: "The thread will unblock when notified by a call to this->notify_one() or this->notify_all(), or spuriously". Is it likely that a condition unblocks spuriously? After all, I'd expect to unblock only after calling notify_* and not "by accident". Is there any way to get diagnostic output when a wait has been called spuriously? The problem I'm having at the moment is: I have PIMPLed Boost.Thread behind some simple wrappers, and I'm using them like this here: Lock lock (mutex_); if (queue.empty ()) { waitForItem.wait (lock); } with Lock being a wrapper for scoped_lock, mutex being a wrapper for mutex and waitForItem being a condition, and funnily enough it goes waiting even though there is an item in queue (i.e., queue.empty () == false). I'm not sure where this is coming from (all access to queue is protected using mutexes), only candidate at the moment is that when inserting, I call notify_one, and if two items get inserted one right after the other, I assume that only one thread is woken up and hence the other remains waiting although there is an item in the queue. It works when I use notify_all (), but this does not smell right to me :/ Thanks, Anteru

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[multi_index] custom template class for handle multi_index map
by damny＠web.de 17 Apr '08

17 Apr '08

hi, i'm a newbie to boost an templates. but for my interrest i experimentalise with that. so i created an example like the following: =============================================================================================== template<typename MAP, typename ELM, typename SC1, typename IT1> class tCanMap { protected: mutable MAP _mpMap; // map mutable SC1 *_scNme; // sorting criteria name ... have to init from derived class public: tCanMap (); MAP &getmap () const; UINT32 setmapelm (ELM val); const ELM *getmapelm (STRING stNme) const; }; template<typename MAP, typename ELM, typename SC1, typename IT1> tCanMap<MAP,ELM,SC1,IT1>::tCanMap() { this->_scNme = NULL; } template<typename MAP, typename ELM, typename SC1, typename IT1> MAP &tCanMap<MAP,ELM,SC1,IT1>::getmap() const { return this->_mpMap; } template<typename MAP, typename ELM, typename SC1, typename IT1> UINT32 tCanMap<MAP,ELM,SC1,IT1>::setmapelm(ELM val) { if (this!=NULL) { this->_mpMap.insert(val); return 0; } return 1; } template<typename MAP, typename ELM, typename SC1, typename IT1> const ELM *tCanMap<MAP,ELM,SC1,IT1>::getmapelm(STRING stNme) const { try { if ( this!=NULL && this->_scNme!=NULL ) { IT1 itr = this->_scNme->find(stNme); if ( itr != this->_scNme->end() ) { return &(*itr); } } } catch(...) {} return NULL; } =============================================================================================== cClass00 { STRING nme; cClass00() {}; STRING getnme() { return this->nme; } } typedef boost::multi_index_container < cClass00, boost::multi_index::indexed_by < boost::multi_index::hashed_unique < BOOST_MULTI_INDEX_CONST_MEM_FUN(cClass00,STRING,getnme) > > > mClass00; typedef mClass00::nth_index<0>::type mClass00ByNme; typedef mClass00ByNme::iterator mClass00ByNmeItr; =============================================================================================== cClass01 : public tCanMap<mClass00,cClass00,mClass00ByNme,mClass00ByNmeItr> { STRING nme; cClass01() { this->_scNme = &(this->_mpMap.get<0>()); } STRING getnme() { return this->nme; } } typedef boost::multi_index_container < cClass01, boost::multi_index::indexed_by < boost::multi_index::hashed_unique < BOOST_MULTI_INDEX_CONST_MEM_FUN(cClass01,STRING,getnme) > > > mClass01; typedef mClass01::nth_index<0>::type mClass01ByNme; typedef mClass01ByNme::iterator mClass01ByNmeItr; =============================================================================================== cClass02 : public tCanMap<mClass01,cClass01,mClass01ByNme,mClass01ByNmeItr> { cClass02() { this->_scNme = &(this->_mpMap.get<0>()); } ... } =============================================================================================== int main (void) { cClass02 *ptClass02 = new cClass02(); ptClass02->fill_maps_with_elements(); ptClass02->getmapelm("cClass01_Element")->dosomething(); // this works ptClass02->getmapelm("cClass01_Element")->getmapelm("cClass00_Element")->dosomething(); // seg vault !!! ... } =============================================================================================== could you explain why the second try of using "getmapelm" results in an error? is there a better way to use a template class like above for handle a multi_index list as a member in similarly classes, whose objects should describe a hierarchical structure? (note: list shall have multiple indizes :o) i use boost 1.34.1 and gcc 3.4.5 (mingw special). many thanx daniel _____________________________________________________________________ Der WEB.DE SmartSurfer hilft bis zu 70% Ihrer Onlinekosten zu sparen! http://smartsurfer.web.de/?mc=100071&distributionid=000000000066

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Re: [Boost-users] BGL problem
by Ronald Garcia 17 Apr '08

17 Apr '08

Hi Giuseppe, I have looked at your code, and it appears that you are not adding a graph_name property map to the dynamic_properties object. Not all graphs have a graph_name property, so it is necessary to use the property map interface to retrieve the graph name. Take a look at libs/graph/test/graphviz_test.cpp, specifically the lines: boost::ref_property_map<graph_t*,std::string> gname( get_property(graph,graph_name)); dp.property("name",gname); Hope this helps, ron On Mar 25, 2008, at 10:22 AM, Giuseppe Di Guglielmo wrote: > Dear Ronald, > I'm using Boost Graph Library. > > I saw this ticket > http://svn.boost.org/trac/boost/ticket/731 > GraphViz reader ignores graph properties. > > I am trying to read the graph name from a graph I loaded from a DOT > file, > but the property seems to be empty. I am not sure that is related > to this > ticket, anyway I hope you can help me. > > I attached a simple example, so it will be very fast for you to > compile > (edit the Makefile to point to your Boost installation library) and > run it. > > The result probably will be, as for me > $ ./runme.sh > The graph name is: '' > > The code to retrieve the graph name is > 57 // THE PROBLEM IS HERE! > 58 // The get_property(efsm_stg, boost::graph_name) function > does not > retrieve the graph name. > 59 boost::graph_property<efsm::stg_t, boost::graph_name_t>::type& > efsm_name = > get_property(efsm_stg, > boost::graph_name); > 60 std::cout << "The graph name is: \'" << efsm_name << "\'" << > std::endl; > 61 //-- > > Best regards, > Giuseppe > > > ---------------------------------------------------------------------- > ------ > Giuseppe Di Guglielmo Dept. of Computer Science - University of > Verona > Strada le Grazie, 15 - 37134 Verona > - Italy > > Phone Office: +39 045 8027049 Fax: +39 045 8027068 > Phone Home: +39 045 6152251 Mobile: +39 347 0493371 > > WWW: http://profs.sci.univr.it/~diguglielmo > > email: giuseppe.diguglielmo(a)univr.it > email: diguglielmo(a)certess.com Skype: giuseppe.diguglielmo > > ---------------------------------------------------------------------- > ------ > > > This e-mail message is intended for the addressee(s) only and may > contain > confidential and or privileged information. If you are not the > intended > recipient of this e-mail message, you should not read, copy, > forward or > otherwise distribute or further disclose the information in it. If > you have > received this e-mail message in error, please contact the > originator of this > e-mail message via e-mail and delete all copies of this message > from your > computer or network, thank you. > > > <graph_name.tgz>

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[1.35, Boost.Test] error when using system in a test
by Christoph Duelli 17 Apr '08

17 Apr '08

The following (see below) test programm compiles under both 1.34.1 and 1.35.0; if linked against 1.35.0 it produces the following error message: Running 1 test case... A unknown location(0): fatal error in "test_call_system": child has exited; pid: 1000; uid: 16129; exit value: 0 *** 1 failure detected in test suite "Master Test Suite" With 1.34.1, no errors are found: Running 1 test case... A *** No errors detected Test program: #define BOOST_AUTO_TEST_MAIN "test-bug" #include <boost/test/auto_unit_test.hpp> BOOST_AUTO_TEST_CASE(test_call_system) { system("echo A"); } Yes, that's it! A single and simple system()-call. (I use these to setup/teardown my test environment; i.e. I create and remove a directory here, really. If there is a better way to do that: hints welcome!) Compiled with gcc 4.1.2 (SLES Linux 10), g++ -I/3rdparty/boost_1_34_1/include/boost-1_34_1 \ -L/3rdparty/boost_1_34_1/lib \ -lboost_unit_test_framework-gcc41 \ -DBOOST_TEST_DYN_LINK \ test.cpp Best regards Christoph

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[boost.function] member function with default values for parameters
by Yan Drugalya 17 Apr '08

17 Apr '08

Folks, What is wrong with the code below: class SomeClass { public: int doSomething(int i=0) { return ++i; } }; boost::function2<int, SomeClass*, int> func = &SomeClass::doSomething; SomeClass sc; std::cout << func(&sc, 1); Currently I'm having following error: An object or reference of type "boost::function2<int,SomeClass *,int,std::allocat or<boost::function_base> >" cannot be initialized with an rvalue of type "int (SomeClass::*)(int)". If I remove default value for parameter i - everything compiles. Complier: VisualAge 7.0 Thanks

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Xcode 3 compile issue
by Dave DeLong 17 Apr '08

17 Apr '08

Hi everyone, I'm attempting to build a project that links against the Boost library, but I keep running into this error: /Developer/SDKs/MacOSX10.5.sdk/usr/include/c++/4.0.0/i686-apple- darwin9/bits/c++locale.h:72: error: 'snprintf' is not a member of 'std' This has come up before on this list ( http://lists.boost.org/boost-users/2008/02/34157.php ), but it doesn't seem like there was an answer. How can I get rid of this? My project requires boost.... Specs: Mac OS X 10.5, Xcode 3.0, CoreDuo chipset Thanks! Dave DeLong

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Mac Xcode 3.0 Boost compile issue
by Daniel Lord 17 Apr '08

17 Apr '08

This is a specific error with Xcode 3.0 on Leopard not a generic Boost question: Something is screwy with the paths between Boost and Xcode: Xcode 3.0 needs to find the Boost includes, so I added my directory containing the top of the Boost tree (the boost_1_34_1 directory) to the User header Search paths in the build configuration for the target. No problem, everything appears to be found. However, adding that search path screws up something else: An error pops up in c++locale.h highlighting the line: const int __ret = std::snprintf(__out, __size, __fmt, __prec, __v); and claiming: "error: 'snprintf' is not a member of 'std'." What the freak? It compiles fine from the command line with g++ and using -I<same path to boost as above>. So it is some wierd interaction with Boost and Xcode paths but it make no sense to me. It's almost as if Boost is redefining something. But what? This does not occur if I don't add the Boost search paths but of course then the Boost definitions are not found. The program is a simple one from O'Reilly's C+++ Cookbook show below: #include <boost/filesystem/operations.hpp> #include <boost/filesystem/fstream.hpp> #include <iostream> using namespace boost::filesystem; int main(int argc, char** argv) { if (argc < 2) { std::cerr << "Usage: " << argv[0] << " [dir name]\n"; return(EXIT_FAILURE); } path fullPath = // Create the full, absolute path name system_complete(path(argv[1], native)); if (!exists(fullPath)) { std::cerr << "Error: the directory " << fullPath.string( ) << " does not exist.\n"; return(EXIT_FAILURE); } if (!is_directory(fullPath)) { std::cout << fullPath.string( ) << " is not a directory!\n"; return(EXIT_SUCCESS); } directory_iterator end; for (directory_iterator it(fullPath); it != end; ++it) { // Iterate through each // element in the dir, std::cout << it->leaf( ); // almost as you would if (is_directory(*it)) // an STL container std::cout << " (dir)"; std::cout << '\n'; } return(EXIT_SUCCESS); }

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Strange use of boost::scoped_ptr in Boost.Process
by Boris 17 Apr '08

17 Apr '08

I found this in the source code of Boost.Process (which is not an official Boost library): // XXX I'm not sure this usage of scoped_ptr is correct... boost::scoped_ptr< STARTUPINFO > si((STARTUPINFO*)new char[setup.m_startupinfo->cb]); I'm not sure either if this is correct. I don't know either why a char array is allocated and not STARTUPINFO directly. Does anyone know though if the code above is correct? STARTUPINFO is a POD (see http://msdn2.microsoft.com/en-us/library/ms686331(VS.85).aspx). Boris

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[ublas] traits.hpp(97) vc8 error in DEBUG mode
by Markus Werle 17 Apr '08

17 Apr '08

Hi! This error occurs in DEBUG mode only. No testcase yet, but you probably have an idea anyway? regards, Markus [..snipped ...]\boost_1_35_0\boost\numeric\ublas\traits.hpp(97) : error C2784: 'boost::numeric::interval<T,Policies> boost::numeric::sqrt(const boost::numeric::interval<T,Policies> &)' : could not deduce template argument for 'const boost::numeric::interval<T,Policies> &' from 'const double' [..snipped...]\boost_1_35_0\boost\numeric\interval\arith2.hpp(198): see declaration of 'boost::numeric::sqrt' [..snipped...]\boost_1_35_0\boost\numeric\ublas\traits.hpp(93) : while compiling class template member function 'double boost::numeric::ublas::scalar_traits<T>::type_sqrt(const double &)' with [ T=double ] [..snipped...]\boost_1_35_0\boost\numeric\ublas\traits.hpp(151) : see reference to class template instantiation 'boost::numeric::ublas::scalar_traits<T>' being compiled with [ T=double ] [..snipped ...]\boost_1_35_0\boost\numeric\ublas\traits.hpp(97) : fatal error C1903: unable to recover from previous error(s); stopping compilation

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