March 2002 - Boost-users - lists.boost.org

Task groups using boost::thread
by gunnarnl 20 Mar '02

20 Mar '02

After overcoming my initial problems with compiling I have another question. I like very much the thread_group concept. My idea is to create different groups running different type of tasks. E.g. one group deals with user request tasks and another deal with responses from a mainframe etc. In addition, I think it would be good to be able to maximize the number of threads running concurrently in a single group. In this way one could tune the processes regarding to the number of CPUs and so that not one single group gets more CPU usage than others etc. I guess I'm not the first one to think about these things. Does anyone have any ideas about these type of task groups? Although it doesn't nearly contain what I want to do, I got the following test work nicely. #include <boost/thread/thread.hpp> #include <boost/thread/xtime.hpp> #include <iostream> #include <windows.h> template<class T> class thread_task { public: thread_task(T* obj) : m_obj(obj) { assert(m_obj != 0); } virtual ~thread_task() { } void operator() () { m_obj->setup(); m_obj->run(); m_obj->cleanup(); delete m_obj; } private: T* m_obj; }; class my_task { public: my_task() {} void setup() { std::cout << "setup " << GetCurrentThreadId() << std::endl; } void run() { std::cout << "Start sleeping in thread " << GetCurrentThreadId() << std::endl; boost::xtime xt; boost::xtime_get(&xt, boost::TIME_UTC); xt.sec += 1; boost::thread::sleep(xt); std::cout << "Woke up " << GetCurrentThreadId() << std::endl; } void cleanup() { std::cout << "cleanup " << GetCurrentThreadId() << std::endl; } }; int main(int argc, char* argv[]) { boost::thread_group threads; int i; for (i = 0; i < 10; ++i) { my_task* aTask = new my_task(); thread_task<my_task> new_task(aTask); threads.create_thread(new_task); } threads.join_all(); return 0; } By the way, is there an operation in boost::thread to get the current thread id?

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Problem linking boost::threads using MSVC6 SP4
by gunnarnl 20 Mar '02

20 Mar '02

I've created a windows console project with VC++ 6.0 and just used one of the examples in the documentation. I've also added the BOOST_HAS_THREADS macro in the settings. The program compiles well in debug mode but gives the following linking errors: Compiling... main.cpp Linking... msvcprtd.lib(MSVCP60D.dll) : error LNK2005: "public: virtual __thiscall std::runtime_error::~runtime_error(void)" (?? 1runtime_error@std@@UAE@XZ) already defined in main.obj msvcprtd.lib(MSVCP60D.dll) : error LNK2005: "public: __thiscall std::runtime_error::runtime_error(class runtime_error::runtime_error const &)" (??0runtime_error@std@@QAE@ABV01@@Z) already defined in main.obj msvcprtd.lib(MSVCP60D.dll) : error LNK2005: "public: __thiscall std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >::~basic_string<char,struct std::char_traits<char>,class std::allocator<char> >(void)" (??1? $basic_strin g@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@QAE@XZ) already defined in main.obj msvcprtd.lib(MSVCP60D.dll) : error LNK2005: "public: __thiscall std::runtime_error::runtime_error(class runtime_error::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (??0runtime_error@std@@QAE@ABV? $basic_strin g@DU?$char_traits@D@std@@V?$allocator@D@2@@1@@Z) already defined in libcpmtd.lib(ios.obj) msvcprtd.lib(MSVCP60D.dll) : error LNK2005: "public: __thiscall std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >(char const *,class basic_ string<char,struct std::char_traits<char>,class std::allocator<char> >::allocator<char> const &)" (??0?$basic_string@DU? $char_traits@D@std@@V?$allocator@D@2@@std@@QAE@PBDABV? $allocator@D@1@@Z) already defined in main.obj LINK : warning LNK4098: defaultlib "MSVCRTD" conflicts with use of other libs; use /NODEFAULTLIB:library Debug/threads.exe : fatal error LNK1169: one or more multiply defined symbols found Error executing link.exe. Any help on this would be appreciated. Gunnar Olerud

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BFS-visitor with gcc3.0.1
by Wintermantel , Marc 20 Mar '02

20 Mar '02

Hello, I tried to complile the following code that worked under gcc 2.95.3 under gcc 3.0.1 and got tons of error messages: typedef adjacency_list< setS, vecS, undirectedS, property< vertex_color_t, default_color_type, property< vertex_degree_t, int, property< vertex_current_degree_t, int, property< vertex_priority_t, int > > > > > Graph; ... std::vector<graph_traits<Graph>::vertices_size_type> dist(num_vertices(G), 0); breadth_first_search (G, e, visitor ( make_bfs_visitor(record_distances(dist.begin(), on_tree_edge() ) ) ) ); ... The errors have something to deal with the visitors, more I could not read out of the errors. When I use a simple array in the form int d[n] it works. Yours truly, Marc Wintermantel Marc Wintermantel IMES - Structures Technology ETH Zurich, LEO C4 Leonhardstrasse 27 CH- 8092 Zurich Tel. ++41 1 633 35 32 Fax. ++41 1 632 17 02 [Non-text portions of this message have been removed]

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Still can't build boost on Linux with gcc 3.0.4
by Peter Simons 19 Mar '02

19 Mar '02

Hi, thanks to some helpful subscriber of this list, I figured out how to tell the Boost Build System where my Python is: I thus initiated the build by calling jam -sPYTHON_ROOT=/usr/local/python -sPYTHON_VERSION=2.2 \ -sBOOST_ROOT=/home/simons/projects/boost-current -sTOOLS=gcc but I am still getting lots of errors when trying to compile the latest version. A complete log of the failing build is available at http://cryp.to/boost-build-log.txt for anyone concerned. I'd appreciate any help on getting these errors fixed! -peter

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Request for reviewers for a book about Boost
by Björn Karlsson 18 Mar '02

18 Mar '02

Dear Boosters, I am currently working on "Beyond The C++ Standard Library - An Introduction to Boost", which is a tutorial-style book about several of the Boost libraries. Where would one seek knowledgeable reviewers? Of course, it is here, and that's the reason for this note. Before saying more, I would like to ask that responses be sent directly to me rather than to the list. The moderators have allowed this note, but this is not intended to become a discussion. Should I receive notes of public interest, I'll post those to the list. Also, for those that are subscribing to both Boost (developers) and Boost-Users, my apologies for cross-posting. Onwards! The book will cover the following libraries (minor modifications to this list may occur): * Any * Array * Bind * Call_traits * Compose * Concept check * Conversion * Functional * Operators * Random * Rational * Regex * Smart_ptr * Static_assert * Tokenizer * Tuple * Type_traits * Utility I am looking for people interested in reviewing one or more chapter(s) (libraries). If you are volunteering, please add information that states the library, or libraries, that you'd be willing to review. Where one reviewer will have a deep knowledge about the libraries, another may only have a strong interest. Both are very welcome! What's in it for you? Not money I'm afraid, but something that is hopefully more valuable: A chance to make the book better, to share some of your knowledge, and maybe to learn something new. Your name in the preface :-). To volunteer, send a comment or ask a question, please contact me directly at bjorn.karlsson(a)readsoft.com. Thanks! Before I end this post: Boost is becoming more and more important for the C++ community, and I would like to thank all participating Boosters for the libraries, the ideas, the research, the discussions and the enthusiasm that sums up to what we call Boost. All of this not only makes the world a better place, it also (which I personally think is more important) makes the world more interesting! Thanks, Bjorn Karlsson [Non-text portions of this message have been removed]

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Re: [Boost-Users] Re: Does filter_iterator work for maps?
by Rodrigo de Salvo Braz 17 Mar '02

17 Mar '02

-----Mensagem original----- De: Jeremy Siek <jsiek(a)cs.indiana.edu> >The above program compiles OK for me with g++ 2.95.2. What compiler are >you using? (there's a good chance the compiler error you are getting is a >bug in your compiler, not in your code or in the Boost code). Hi Jeremy, Thanks for the reply. Yes, I think it is the compiler too. I am using the Borland C++ Builder compiler 5.5 (the free command line compiler Borland made available a while ago). I am not sure yet I am not making a mistake, because I would expect this to be a popular compiler and simple things like this to have been found by now. All it takes to use the iterator adaptor libraries is including the header files, right? Thanks, Rodrigo _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

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regex expression core dumps with \\
by soleani 17 Mar '02

17 Mar '02

Hi there, I've been using regex++ (v 3) for a while now. It's great! I just found out that my regex core dumps my program, look: std::string StringUtilities::getMsqlEscapedString( const char* input ) { if ( input == NULL ) return ""; cerr << "Hello" << endl; std::string inputStr( input ); cerr << "Hello111 (" << inputStr << ")" << endl; static const boost::regex expression1( "\\" ); cerr << "Hello222" << endl; string temp = boost::regex_merge( inputStr, expression1, "\\\\" ); cerr << "Hello33" << endl; static const boost::regex expression2( "'" ); return boost::regex_merge( temp, expression2, "\\'" ); } // StringUtilities::getMsqlEscapedString That's all I have. When I call it I see this: Testing getMsqlEscapedString... Hello Hello111 (hello) Aborted (core dumped) So, it seems that the call to: static const boost::regex expression1( "\\" ); makes it core dump. I went and changed that regular expression by "\"", just for kicks, and it works; it doesn't do what I want but it doesn't core dump. Anything I should do to avoid this problem? thanks, -Anibal

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Error with boost::regex library with Borland C++ Builder 6
by ynaig2k 17 Mar '02

17 Mar '02

Hi, I tried everything to understand why I get the error "Abnormal program termination" in the second run of the function with the following code: void function() { regex e( std::string(Edit1->Text.c_str()) ); cmatch what; string response; TFileStream* file = new TFileStream( "1.htm", fmOpenRead ); response.resize(file->Size+1); file->Read(response.begin(), file->Size); response[file->Size] = 0; delete file; std::string::const_iterator start; start = response.begin(); while( regex_search( start, what, e ) ) { for ( unsigned int i = 0 ; i < what.size() ; i++ ) { { std::string result = std::string(what[i].first, what[i].second); Memo1->Lines->Add( result.c_str() ); } Memo1->Lines->Add(""); start = what[0].second; } } Thanks

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Re: [Boost-Users] Re: Does filter_iterator work for maps?
by Rodrigo de Salvo Braz 16 Mar '02

16 Mar '02

-----Mensagem original----- De: Jon Kalb <kalb(a)LibertySoft.com> Para: Boost-Users(a)yahoogroups.com <Boost-Users(a)yahoogroups.com> Data: Sexta-feira, Março 15, 2002 09:01 Assunto: Re: [Boost-Users] Re: Does filter_iterator work for maps? On 3/15/02 4:37 PM, "rodrigo_braz" <rodrigo_braz(a)yahoo.com> wrote: >> Actually my main problem with this iterator is in the code below: >CodeWarrior doesn't complain about this code, but I think that it should be: As Jeremy pointed out, that doesn't work. It sounds like it is a compiler issue (I am using Borland). I will go back to the boost pages to see if there is anything I can do about it. Thanks, Rodrigo _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

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Does filter_iterator work for maps?
by rodrigo_braz 16 Mar '02

16 Mar '02

Hi, I don't see a reason for filter_iterator not to work with map iterators. However, the program below doesn't work. I get a compiler error "Cannot generate template specialization from 'make_filter_iterator<Predicate,Iterator> (Iterator,Iterator,const Predicate &)' in function main()" Any ideas? Thanks, Rodrigo #include <map> #include <ostream> #include "boost/iterator_adaptors.hpp" #include <algorithm> using namespace std; using namespace boost; struct pair_is_active { bool operator()(const pair<const size_t,float>& p) { return 0 < p.second; } }; ostream& operator<<(ostream& o, pair<const size_t, float> p) { return o << "(" << p.first << ", " << p.second << ")"; } int main() { map<size_t,float> m; m[0] = 10; m[1] = 15; m[2] = 0; m[3] = 13; copy(boost::make_filter_iterator<pair_is_active>(m.begin, m.end()), boost::make_filter_iterator<pair_is_active>(m.end(), m.end()), ostream_iterator<pair<const size_t,float> >(cout,",")); return 0; }

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