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Threads, condition variables, and signals
by Scott Gifford 08 Oct '07

08 Oct '07

Hello, I'm writing a multithreaded server on Unix using boost::thread. The basic operation is fairly straightforward; a master thread starts up worker threads, and coordinates various management tasks using condition variables. As with most Unix servers, the server is shut down with an OS signal telling the server to shut down. The server catches this signal, then simply calls exit(1). Any important cleanup happens in the destructors of global variables, so it will happen properly no matter how the server exits. One object which is always cleaned up is the object for the master thread. The master thread sets a flag, then does a notify_all() on some condition variables to tell the other threads to shut down, The problem I'm having is that if the master thread is waiting on a condition variable when the signal arrives, and the destructor does a notify_all() on that condition variable, then the destructor for the boost::condition variable hangs. For example, if I run the included code and hit CTRL-C after a short bit, I get this output: Waiting... ^C Caught signal 2 Destroyed ThreadTest Running destructor 1 [ ... hangs ... ] Here is the program: #include <iostream> #include <signal.h> #include <boost/thread.hpp> #include <boost/thread/mutex.hpp> #include <boost/thread/condition.hpp> template<int n> struct PrintOnDestruct { ~PrintOnDestruct() { std::cout << "Running destructor " << n<< std::endl; } }; class ThreadTest { public: void doSomething() { boost::mutex::scoped_lock lock(myMutex); while(true) { std::cout << "Waiting..." << std::endl; myCond.wait(lock); } } ~ThreadTest() { boost::mutex::scoped_lock lock(myMutex); myCond.notify_all(); std::cout << "Destroyed ThreadTest" << std::endl; } private: PrintOnDestruct<2> d2; boost::mutex myMutex; boost::condition myCond; PrintOnDestruct<1> d1; }; // Exit properly on signal void sighandle(int sig) { std::cerr << "Caught signal " << sig << std::endl; exit(1); } ThreadTest tt; int main() { // Get ready to handle signals signal(SIGINT,sighandle); tt.doSomething(); } Does anybody have any suggestions for a straightforward way to handle this properly? Thanks! ----ScottG.

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[preprocessor] using __FILE__ with BOOST_PP_FILENAME_x
by Server Levent Yilmaz 08 Oct '07

08 Oct '07

Hi all, Please take a look as this trivial example of file iteration: // trivial.h #if !BOOST_PP_IS_ITERATING #ifndef TRIVIAL_H #define TRIVIAL_H #include <boost/preprocessor/iteration/iterate.hpp> #define BOOST_PP_FILENAME_1 "trivial.h" //!!! #define BOOST_PP_ITERATION_LIMITS (1, 3) ??=include BOOST_PP_ITERATE() #endif // TRIVIAL_H #else BOOST_PP_ITERATION() #endif Perhaps not so obvious many (wasn't to me), that #define BOOST_PP_FILENAME_1 __FILE__ doesn't work. One has to specify (kind of like hardcode) the file's name in there.. Is there some, possibly contrived, way to achieve automation of this? regards, - Levent PS: What an AMAZING library this Boost.Preprocessor is!? -- Server Levent Yilmaz Mechanical Engineering University of Pittsburgh

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exp functions with interval
by Mark Beinker 08 Oct '07

08 Oct '07

Hi, I was trying to use the boost interval class using g++ under cygwin and ubuntu, but unfortunately, I have trouble to use the exp function. The following code: #include <iostream> #include <cmath> #include <boost/numeric/interval.hpp> #define DOUBLE boost::numeric::interval<double> int main(int argc, char** argv) { DOUBLE x(4,5); std::cout.precision(19); DOUBLE res = exp(x); std::cout<<'['<<res.lower()<<", "<<res.upper()<<']'<<std::endl; return 0; } generates the following compile error: /usr/include/boost/numeric/interval/transc.hpp: In function `boost::numeric::interval<T, Policies> boost::numeric::exp(const boost::numeric::interval<T, Policies>&) [with T = double, Policies = boost::numeric::interval_lib::policies<boost::numeric::interval_lib::rounded_math<double>, boost::numeric::interval_lib::checking_strict<double> >]': itest.cpp:14: instantiated from here /usr/include/boost/numeric/interval/transc.hpp:34: error: 'struct boost::numeric::interval_lib::rounded_math<double>' has no member named 'exp_down' itest.cpp:14: instantiated from here /usr/include/boost/numeric/interval/transc.hpp:34: error: 'struct boost::numeric::interval_lib::rounded_math<double>' has no member named 'exp_up' I use boost version 1.34.1. Any idea why this doesn't work? Regards, Mark

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[string_algo] Case-insensitive keys in map with is_iless?
by Boris 07 Oct '07

07 Oct '07

Am I supposed to be able to use boost::algorithm::is_iless (see http://www.boost.org/doc/html/boost/algorithm/is_iless.html) to create a map with case-insensitive keys? I wonder as either it is broken in VS2005 or I do something wrong: #include <boost/algorithm/string.hpp> #include <string> #include <map> int main() { std::map<std::string, int, boost::algorithm::is_iless> m; m["test"] = 1; } C:\Program Files\Microsoft Visual Studio 8\VC\include\xlocale(583) : error C2440: 'type cast' : cannot convert from 'unsigned char' to 'std::basic_string<_Elem,_Traits,_Ax>' ... C:\Program Files\Microsoft Visual Studio 8\VC\include\xlocale(561) : error C2440: 'type cast' : cannot convert from 'std::basic_string<_Elem,_Traits,_Ax>' to 'unsigned char' The assignment causes the problem. If you use insert() you get the same compiler error. Without the assignment the code compiles fine. Boris

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"Missing" lib for 1_34_1 using MSVC-71
by Larry 07 Oct '07

07 Oct '07

I had a program that I had built with Boost 1_34 and it worked well (built with MSVC 7.1). I downloaded 1_34_1 and built 1_34_1 for VC8 and VC7.1 using bjam 3.1.14. bjam --toolset=msvc-7.1 install I switched the program build to use Boost 1_34_1 and the build fails looking for libboost_date_time-vc71-mt-sgd-1_34_1.lib as part of the link. Going back to the Boost build I find msvc.archive bin.v2\libs\date_time\build\msvc-71\debug\link-static\runtime-link-static\libboost_date_time-vc-sgd-1_34_1.lib common.copy C:\Boost\lib\libboost_date_time-vc-sgd-1_34_1.lib 1 file(s) copied. The only thing I changed was the include list entry from c:\boost\include\boost_1_34 to c:\boost\include\boost_1_34_1. The lib directory is the same in both cases. I didn't find anything looking through the boost.user group or in the doc but perhaps I looked at it and just didn't realize the answer was there. Perhaps I didn't do something I should have or did something I shouldn't have. Any ideas? I got surprised (probably again) when building Boost because I had run vcvars32.bat for MSVC 7.1 and then did bjam --toolset=msvc install and the surprise was it built for MSVC 8.0. The doc does say the build will find the VC compiler but I had sort of assumed it would use what was in the environment before searching elsewhere for a compiler version. But after that I ran bjam --toolset=msvc-71 install and it ran without complaint. I did several iterations of the 7.1 build including a build with -a and also did a --clean followed by a Boost build and neither altered the outcome of the Boost build (that I could see) and did not alter the outcome of the program build with VC 7.1. The program build was done via VS. Moving the include back to 1_34 works. Larry

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[thread] example to delegtate jobs to threads
by Torsten Mohr 07 Oct '07

07 Oct '07

Hi, i wrote a small test project that makes use of boost::thread to split jobs into parts that are delegated to threads. A class "Job" contains a state machine (IDLE, EXECUTING, ABORTED, ...). That class can be derived from and methods "execute" and "report" can be overwritten. A class JobProvider can be derived from to feed new data to a Job. A Template "Foreman" can then start several threads and delegate Jobs that get their data from "JobProvider" to the Jobs and they report when they are done. In the example, MyJobProvider provides numbers from 3 to 100. MyJob::execute calculates if these numbers are prime. MyJob::report prints out the numbers that are prime. All the methods "report" are protected, only one of them at a time is ever called, methods "execute" are run in parallel. The performance is poor, can anybody give me a hint why? Best regards, Torsten. ######## job.h: #ifndef JOB_H #define JOB_H 1 #include <boost/thread.hpp> extern boost::mutex io_mutex; #define QWE { boost::mutex::scoped_lock lck(io_mutex); printf("file %s line %i\n", __FILE__, __LINE__); } class Job { boost::mutex job_mutex; boost::mutex cond_mutex; boost::mutex* m_report_mutex; boost::condition* m_condition; boost::thread* thr; bool m_stopped; int m_state; void setState(int state); protected: bool is_stopped(void); public: enum { CMD_IDLE = 212, CMD_EXEC, CMD_KILL }; enum { STATE_IDLE = 37, STATE_EXEC_PREPARE, STATE_EXEC, STATE_EXEC_ABORTED, STATE_REPORT_PREPARE, STATE_REPORT, STATE_DEAD }; void set_foreman_data(boost::mutex* report_mutex, boost::condition* condition); void init(void); virtual void execute_handler(void); void report_handler(void); void fork(void); int getState(void); void doCommand(int command); virtual void execute(void); virtual void report(void); }; class JobProvider { public: bool provide(Job& j); }; #endif ######## job.cc: #include <boost/thread.hpp> #include <boost/bind.hpp> #include "job.h" int Job::getState(void) { boost::mutex::scoped_lock lock(job_mutex); return m_state; } void Job::setState(int state) { boost::mutex::scoped_lock lock(job_mutex); m_state = state; } void Job::doCommand(int cmd) { boost::mutex::scoped_lock lock(job_mutex); // sparse transitions if((m_state == STATE_EXEC || m_state == STATE_EXEC_PREPARE) && cmd == CMD_KILL) { m_state = STATE_EXEC_ABORTED; m_stopped = true; } else if(m_state == STATE_IDLE && cmd == CMD_EXEC) { m_state = STATE_EXEC_PREPARE; } else if(m_state == STATE_IDLE && cmd == CMD_KILL) { m_state = STATE_DEAD; m_stopped = true; } } bool Job::is_stopped(void) { boost::mutex::scoped_lock lock(job_mutex); return m_stopped; } void Job::execute_handler(void) { int state; do { state = getState(); switch(state) { case STATE_EXEC_PREPARE: execute(); state = getState(); if(state != STATE_EXEC_ABORTED) { boost::mutex::scoped_lock lock(*m_report_mutex); report(); m_condition->notify_one(); setState(STATE_IDLE); } break; case STATE_DEAD: case STATE_EXEC_ABORTED: return; } } while(1); } void Job::init(void) { m_state = STATE_IDLE; } void Job::fork(void) { thr = new boost::thread(boost::bind(execute_handler, this)); } void Job::report_handler(void) { boost::mutex::scoped_lock lock(*m_report_mutex); report(); } void Job::set_foreman_data(boost::mutex* report_mutex, boost::condition* condition) { m_report_mutex = report_mutex; m_condition = condition; } void Job::execute(void) { } void Job::report(void) { } ######## foreman.h: #ifndef FOREMAN_H #define FOREMAN_H 1 #include <boost/thread.hpp> #include <boost/bind.hpp> #include "job.h" template<class JOBB, class JOBB_PROVIDER> class Foreman { JOBB* jb; JOBB_PROVIDER* m_provider; int m_threads; bool m_finished; boost::mutex report_mutex; boost::mutex m_cond_mutex; boost::condition m_condition; boost::thread* me; void handler(void); public: Foreman(int threads, JOBB_PROVIDER* provider); ~Foreman(); void spawn(void); void cleanup(void); void abort(void); bool is_finished(void); }; template<class JOBB, class JOBB_PROVIDER> Foreman<JOBB, JOBB_PROVIDER>::Foreman(int threads, JOBB_PROVIDER* provider) : m_threads(threads), m_provider(provider) { jb = new JOBB[m_threads]; } template<class JOBB, class JOBB_PROVIDER> Foreman<JOBB, JOBB_PROVIDER>::~Foreman() { delete[] jb; } template<class JOBB, class JOBB_PROVIDER> void Foreman<JOBB, JOBB_PROVIDER>::handler(void) { bool all_done; do { boost::mutex::scoped_lock lock(m_cond_mutex); all_done = true; for(int i = 0; i < m_threads; ++i) { int state = jb[i].getState(); if(state == Job::STATE_IDLE) { if(m_provider->provide(jb[i])) { jb[i].doCommand(Job::CMD_EXEC); all_done = false; } else { m_finished = true; } } else { all_done = false; } } if(m_finished || all_done) { return; } m_condition.wait(lock); } while(1); // (!m_finished || !all_done); } template<class JOBB, class JOBB_PROVIDER> void Foreman<JOBB, JOBB_PROVIDER>::spawn(void) { for(int i = 0; i < m_threads; ++i) { jb[i].set_foreman_data(&report_mutex, &m_condition); jb[i].init(); jb[i].fork(); } m_finished = false; // me = new boost::thread(boost::bind(handler, this)); handler(); } template<class JOBB, class JOBB_PROVIDER> void Foreman<JOBB, JOBB_PROVIDER>::cleanup(void) { // me->join(); } template<class JOBB, class JOBB_PROVIDER> void Foreman<JOBB, JOBB_PROVIDER>::abort(void) { } template<class JOBB, class JOBB_PROVIDER> bool Foreman<JOBB, JOBB_PROVIDER>::is_finished(void) { return m_finished; } #endif ######## my_job.h: #ifndef MY_JOB_H #define MY_JOB_H 1 #include "job.h" class MyJob : public Job { int m_suspect; bool is_prime; public: MyJob(); virtual void execute(void); virtual void report(void); void setJobStuff(int suspect); }; class MyJobProvider : public JobProvider { int m_actual; public: MyJobProvider(); bool provide(MyJob& j); }; #endif ######## my_job.cc: #include <iostream> #include <math.h> #include "my_job.h" #include "job.h" MyJob::MyJob() { m_suspect = 0; } void MyJob::setJobStuff(int suspect) { m_suspect = suspect; } void MyJob::execute(void) { int root = (int)sqrt((double)m_suspect); for(int j = 2; j <= root; j++) { if(is_stopped()) { return; } if((m_suspect % j) == 0) { is_prime = false; return; } } is_prime = true; } void MyJob::report(void) { if(is_prime) { std::cout << m_suspect << " is prime" << std::endl; } } MyJobProvider::MyJobProvider() : m_actual(3) {} #define NN 100 bool MyJobProvider::provide(MyJob& j) { j.setJobStuff(m_actual); m_actual++; if(m_actual > NN) return false; return true; } ######## qwe.cc: #include <iostream> #include "job.h" #include "my_job.h" #include "foreman.h" boost::mutex io_mutex; void test1(void) { MyJobProvider p; MyJob j; while(p.provide(j)) { j.execute(); j.report(); } } void test2(void) { MyJobProvider p; Foreman<MyJob, MyJobProvider> fm(7, &p); fm.spawn(); do { } while(!fm.is_finished()); fm.cleanup(); } int main(int argc, char** argv) { test2(); return 0; }

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Serializing a Method
by at forum 07 Oct '07

07 Oct '07

Hi to all I am new to the boost library, I downloaded it and I am doing some tests. I was using MFC serialization. I want to do something like this : template<class _CReceiver, class _CMemberType> class CASetMemberCommand { friend class boost::serialization::access; public: typedef void (_CReceiver::* Action)(_CMemberType) ; protected: _CReceiver *m_pReceiver; _CMemberType m_Property; Action m_fnAction; public: CASetMemberCommand() { m_pReceiver = NULL; } CASetMemberCommand(_CReceiver *pReceiver, Action fnAction, _CMemberType memberProperty) { m_pReceiver = pReceiver; m_fnAction = fnAction; m_Property = memberProperty; } ~CASetMemberCommand() { } virtual void Execute() { if(m_pReceiver) (m_pReceiver->*m_fnAction)(m_Property); } template<class Archive> void serialize(Archive & ar, const unsigned int /* file_version */){ ar & BOOST_SERIALIZATION_NVP(m_pReceiver) //& BOOST_SERIALIZATION_NVP(m_fnAction) & BOOST_SERIALIZATION_NVP(m_Property); } void Save(const char * filename) { std::ofstream ofs(filename); assert(ofs.good()); boost::archive::xml_oarchive oa(ofs); oa << BOOST_SERIALIZATION_NVP(this); } void Load( const char * filename) { std::ifstream ifs(filename); assert(ifs.good()); boost::archive::xml_iarchive ia(ifs); ia >> BOOST_SERIALIZATION_NVP(*this); } }; int main(int argc, char *argv[]) { gps_position pos(32,52,25.0f); CASetMemberCommand<gps_position,int> cmd(&pos,&gps_position::SetMinutes,25); CASetMemberCommand<gps_position,int> cmd4(&pos,&gps_position::SetDegrees,25); cmd.Execute(); SaveCommand(cmd,"D:/test.xml"); cmd.Save("D:/Test2.xml"); CASetMemberCommand<gps_position,int> cmd2; cmd2.Load("D:/Test2.xml"); return 0; } the problem is that BOOST_SERIALIZATION_NVP(m_fnAction) is not working (compile errors); Is there any way to save a methode of w class, so it can be loaded and used later? Thank you

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Allocator and smart_ptrs
by Seweryn Habdank-Wojewódzki 06 Oct '07

06 Oct '07

Dears I found that only shared_ptr can use allocator. Is there any possibility to join the existing allocator and the other smart_ptrs. Why the rest smart_ptrs can not use allocators? Regards. -- |\/\/| Seweryn Habdank-Wojewódzki \/\/

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Need a help about boost.thread
by Steven Woody 06 Oct '07

06 Oct '07

hi, i am doing a job and considering if boost.thread can help. what i am doing is writing some code for other one's use. my code will be called by many threads, and accessing some shared data. my problem is how to keep my code thread-safe. i have no way to control how those other threads were created ( actually, those had already done by another team using windows MFC, and, for some reasons, my code can not use MFC, is has to be portable bwteen Linux and Windows ). in breif, you can think my code in a way of producer/consumer pattern. the producer is a rouine which will be called by many threads ( which are actaully connected sockets created by a listening socket ), and the consumer routine will be called by another thread ( which is actually GUI's main thread ). what i expected is: 1, only one producer can write to the shared data; 2, when a producer is writting, other producers have to busy waiting; and the GUI thread should immediately exit; 3, when GUI thread is reading, no producer can write to the shared data; to my problem, does the boost.thread can help? thanks in advance. -- woody then sun rose thinly from the sea and the old man could see the other boats, low on the water and well in toward the shore, spread out across the current.

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Boost/C++ group on facebook
by Jan Stetka 06 Oct '07

06 Oct '07

Boost/C++ group on facebook: Already have 47 members! Show your support for boost (unofficially) http://www.facebook.com/group.php?gid=4200526117

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boost bindings
by e r 06 Oct '07

06 Oct '07

i, i looked at previous posts on this topic. did not help, a suggestion would be appreciated: installed atlas version 3.6.0-20.6 /usr/lib/atlas3-test runs just fine. header cblas.h and clapack.h are in /usr/include/ which is by default in my include path. Configuration: -I/usr/local/include/boost_1_34_1 -I/usr/local/include/boost-bindings -L/usr/lib/atlas -llapack -lblas i'm trying to run the program: #include <boost/numeric/bindings/atlas/clapack.hpp> #include <boost/numeric/bindings/traits/ublas_matrix.hpp> #include <boost/numeric/bindings/traits/std_vector.hpp> // #include <atlas/cblas.h> namespace ublas = boost::numeric::ublas; namespace atlas = boost::numeric::bindings::atlas; int main() { std::size_t n = 5; ublas::matrix<double> a(n, n); // fill matrix a std::vector<int> ipiv (n); // pivot vector atlas::lu_factor (a, ipiv); // alias for getrf() atlas::lu_invert (a, ipiv); // alias for getri() return 0; }; i get the error Building target: testing_numeric_bindings Invoking: GCC C++ Linker g++ -L/usr/lib/atlas -o"testing_numeric_bindings" ./main.o -llapack -lblas ./main.o: In function `boost::numeric::bindings::atlas::detail::getrf(CBLAS_ORDER, int, int, double*, int, int*)': /usr/local/include/boost-bindings/boost/numeric/bindings/atlas/clapack_overloads.hpp:87: undefined reference to `clapack_dgetrf' ./main.o: In function `boost::numeric::bindings::atlas::detail::getri(CBLAS_ORDER, int, double*, int, int const*)': /usr/local/include/boost-bindings/boost/numeric/bindings/atlas/clapack_overloads.hpp:163: undefined reference to `clapack_dgetri' collect2: ld returned 1 exit status make: *** [testing_numeric_bindings] Error 1 make: Target `all' not remade because of errors. Build complete for project testing_numeric_bindings

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ublas/matrix product/efficiently compute A * B * C
by e r 05 Oct '07

05 Oct '07

currently i do: boost_auxiliary::matrix_double D; boost::numeric::ublas::axpy_prod(A, B, D, true); boost::numeric::ublas::axpy_prod(D, C, D, true); there must be a better way? A * B * C generates an ambiguous overloaded operator* message (ambiguous with element-wise product, i read). pls help.

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[interprocess] - Usage of boost::interprocess::open_or_create mode
by Srinivas Gardas 05 Oct '07

05 Oct '07

Hi, I am quite new to boost. Are there any code examples around usage of 'open_or_create' mode for ceating the shared_memory_object? My problem is, after we create a 'shared_memory_object' using 'open_or_create' there is no way to know whether it created 'created' a file or 'opened' an already existing file. We need this apparently, because if we are creating a new file, we have to '*construct<container>("MySharedMemory") *' the file with the desired container, otherwise we have to '* find<container>("MySharedMemory")*'. All the usage examples I could get were only around 'create_only' and then 'open_only' modes.. My idea is to write one single method, that'd use the 'open_or_create' mode so that we don't have to bother.. a sequence of creation and then usage.. I am not sure if I was clear enough in putting my problem across, please feel free to respond with questions. Really appreciate any help around this. Thanks & Regards, Srinivas Gardas

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[random] getting a 50% probability generator
by Jeffrey Holle 05 Oct '07

05 Oct '07

I am at the point in my application where I must introduce randomness to a sort routine. Basically when 2 elements are equal, I need to create a 50% probability that they will be swapped. What is the correct boost::random library resource to code this? I've attempted to use uniform_01, by creating an instance of it with this type: typedef boost::uniform_01<boost::minstd_rand, double> rand_gen_t; However, after getting it constructed as a class attribute, I find accessing it with: cout << (*pRand_gen++) << endl; It produces numbers like 1 134784888 134784288 2 134784845 134784224 134785176 5 0 134784376 134785328 0. What I want is a sequence like 0 1 0 1 0 1 0 0 0 1 1 1 1 0 1 0 1 that is sort of random.

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[boost-users] enable_if on boost::operators compile error on visual c++.
by chun ping wang 05 Oct '07

05 Oct '07

Given this code which is suggested by David Abraham.... template <class T, class U> char (& is_op_test(boost::operators<T,U> const&) )[2]; template <class T> char is_op_test(T const&); template<class T> T const& make(); template <class T> struct is_operators : boost::mpl::bool_<(sizeof(is_op_test(make<T>())) == 2)> {}; and this function declaration. template <typename T, template <typename ELEM, typename = std::allocator<ELEM> > class CONT > typename boost::enable_if<boost::mpl::or_<boost::is_integral<T>, boost::is_operators<T> >, CONT<T> >::type primelist(const T& MAX_BOUND, const T& K, boost::function<bool(const T&, const T&)> f); I compile with T = int and it works. When i compile with T = BigInteger I get the following errors. ./cs512/c++/primeMain.cpp(78) : error C2770: invalid explicit template argument(s) for 'boost::enable_if<boost::mpl::or_<boost::is_integral<T>,boost::is_operators<T> >,CONT<T>>::type primelist(const T &,const T &,boost::function<bool(const T &,const T &)>)' ./cs512/c++/primeMain.cpp(24) : see declaration of 'primelist'" BigInteger class declaration looks like this.. class BigInteger : public BigUnsigned, boost::operators<BigInteger>, boost::operators<BigInteger, int> { }; thanks for the help.

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lexical_cast
by Peter Sliepenbeek 05 Oct '07

05 Oct '07

Hi all, The test below fails: #include <iostream> #include <boost/lexical_cast.hpp> int main(int argc, char* argv[]) { std::string s; try { double d = std::numeric_limits <double> ::max(); s = boost::lexical_cast <std::string> (d); } catch (const boost::bad_lexical_cast&) { std::cout << "double to std::string fails" << std::endl; } try { double dd = boost::lexical_cast <double> (s); } catch (const boost::bad_lexical_cast&) { std::cout << "std::string to double fails" << std::endl; } return 0; } To solve this issue I propose to alter the line "stream.precision(std::numeric_limits<Target>::digits10 + 1" in the constructor for lexical_stream into "stream.precision(std::numeric_limits<Target>::digits10 - 1". Regards, P. Sliepenbeek --------------------------------- Be a better Heartthrob. Get better relationship answers from someone who knows. Yahoo! Answers - Check it out.

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[Boost.FileSystem] File or Wildcards in Path? How-to do this?
by Lawrence Spector 05 Oct '07

05 Oct '07

Here's a simple example. Is there a way to do achieve this effect? std::string folderName = "C:\\*.sys"; boost::filesystem::path fsDirectoryPath = boost::filesystem::system_complete( boost::filesystem::path(folderName, boost::filesystem::native)); boost::filesystem::directory_iterator end_iter; for (boost::filesystem::directory_iterator dir_itr(fsDirectoryPath); dir_itr != end_iter; ++dir_itr) // throws exception { std::cout << "Contains the following file: " << dir_itr->string() << std::endl; } // end for When I do this, I get the following exception: boost::filesystem::basic_directory_iterator constructor I don't see any documentation for how to narrow your searches with wildcards or how to only find files that match a particular file name. Am I missing something? Obviously you can refine your search later in the loop, but that is inefficient. Please let me know. Thanks, Lawrence

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A tuple performance question
by Peng Yu 05 Oct '07

05 Oct '07

Hi, It is mentioned at http://www.boost.org/libs/tuple/doc/tuple_users_guide.html#performance that the following two ways would be different in term of performance. ////////////// void f1(int&, double&); tuple<int, double> f2(); //Then, the call #1 may be slightly faster than #2 in the code below: int i; double d; ... f1(i,d); // #1 tie(i,d) = f2(); // #2 /////////////////// What about the current commonly used compiler, such as GCC? Are #1 and #2 different in GCC? Does the compiler always have some way to optimize #2 to make it as good as #1? Is it just a matter of fact whether the optimization method is implemented? Or #2 can never be made as good as #1? Thanks, Peng

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Any way to work around missing <locale> under Windows CE ?
by luper rouch 05 Oct '07

05 Oct '07

The standard <locale> include file is not shipped with the windows CE/mobile sdks, and therefore lots of boost parts are unusable. Is there a way to work around this problem in boost ? Luper Rouch

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[interprocess]failed to build doc
by Sean Huang 05 Oct '07

05 Oct '07

Has anybody had any success in building doc for interprocess (trunk version). Doxygen 1.5.3 crashed and I switched to 1.4.7 but I'm still getting the following errors: xslt-xsltproc .\..\..\bin.v2\libs\interprocess\doc\msvc-8.0\debug\threading-multi\autodoc -xml.boostbook warning: failed to load external entity "Reference" cannot parse Reference set XML_CATALOG_FILES=..\..\..\bin.v2/boostbook_catalog.xml "xsltproc.exe" --stringparam boost.doxygen.refid " "reference"" --stringparam boost.doxygen.reftitle ""Boost.Interprocess Reference"" --xinclude -o "..\..\..\bin.v2\libs\interprocess\doc\msvc-8.0\debug\threading-multi\autodo c-xml.boostbook" "boost\boost\tools\boostbook\xsl\doxygen\doxygen2boostbook.xsl" "..\..\..\bin.v2\libs\interprocess\doc\msvc-8.0\debug\threading-multi\autodo c-xml.doxygen" ..failed xslt-xsltproc .\..\..\bin.v2\libs\interprocess\doc\msvc-8.0\debug\threading-multi\autodoc -xml.boostbook... ..skipped <p.>autodoc.xml for lack of <p..\..\..\bin.v2\libs\interprocess\doc\msvc-8.0\debug\threading-multi>autod oc-xml.boostbook... ..skipped <p..\..\..\bin.v2\libs\interprocess\doc\msvc-8.0\debug\threading-multi>inter process.docbook for lack of <p.>a utodoc.xml... ..skipped <phtml>standalone_HTML.manifest for lack of <p..\..\..\bin.v2\libs\interprocess\doc\msvc-8.0\debug\threading- multi>interprocess.docbook... ..failed updating 1 target... ..skipped 3 targets... Thanks, Sean

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Re: [Boost-users] follow up on regex questions
by Mike Marchywka 04 Oct '07

04 Oct '07

OK, I think my earlier concern about greta dropping data was incorrect as it was the result of hastily adapting a piece of code for testing- that wouldn't have occured before. I went back to verify that boost still gives the same results as greta with simpler regexes and still have identical results. Is there anything that "()" can do to the stack that could be causing flakey results? This fails on some data ( program hangs or seg faults): ATG(.)*?(TAG|TAA|TGA) >rule|2|DNA Euk ORF This works on data I have ( although I thought I saw it failing earlier, I have yet to see the 1000 other regex's fail in boost ): ATG.*?(TAG|TAA|TGA) >rule|2|DNA Euk ORF The working regex's do not have non-terminal "()"- while they may have "()" these are only at begin or end and include two choices, one of which is "^" or "|" ) My calling code looks something like this ( again, everything is char* ) while(regex_search(start, end, what, expression, flags)) { if (which>=what.size()) { es<<MM_MARK<<" which "<< which <<" vs size "<<what.size()<<'\n'; ; return -1; } int st=what[which].first - sample; int len=what[which].second-what[which].first; typedef VecTy::value_type Val; rv.push_back(Val(st,st+len )); start = what[which].second; // This makes things OVERLAP, may not be desired behavior. if ( rv.olap_group()) start = what[0].first+1; if ( rv.olap_which()) start = what[which].first+1; // update flags: flags |= boost::match_prev_avail; flags |= boost::match_not_bob; } Thanks again. >From: "John Maddock" <john(a)johnmaddock.co.uk> >Reply-To: boost-users(a)lists.boost.org >To: <boost-users(a)lists.boost.org> >Subject: Re: [Boost-users] follow up on regex questions >Date: Thu, 4 Oct 2007 17:37:22 +0100 > >Mike Marchywka wrote: > > Hi, > > Thanks for your help in the past. I would normally drop the issue at > > this point > > until I get my build environment cleaned up > > (" My build is messed up, I haven't read the documentation. What is > > wrong with YOUR library?" LOL). > > but I do have one more question which I believe is related to boost > > regex processing. > > If someone has a known good regex test program or can point to an > > obvious problem > > it may be helpful. > >You mean libs/regex/test/regress/*.cpp ? > >It would be a good idea to build and run this to verify the sanity of your >setup at least: I still have a suspision that the binaries you are using >are >not compatible with your build options or regex headers, but I can't be >sure. > > > Again, this code seems to work with Microsoft's > > greta and boost gives identical results on a longer list of SIMPLER > > regexes so I reasonably believe that the problem is due to handling > > of more complicated expression ( One caveat, to be complete, is that > > greta did seem to return some spurious > > results but they are easily filter programmatically, things like > > negative location, > > but the plausible ones that I have checked manually are right). > > However, on this sequence of regexes (regexi?) I get either an abort > > OR the program hangs > > later on non-sensical execution (I know, "Gee, you have a build > > problem and the stack is messed up?"). > > > > myboost.cpp114 (GU.*?TACTAAC.{20,40}AG|^)(.*?)(GU.*?TACTAAC.{20,40}AG) > > myboost.cpp114 ATG(...)*?(TAG|TAA|TGA) > > myboost.cpp114 TATAA.*?ATAAA > > myboost.cpp114 (GU.*?TACTAAC.{20,40}AG|^)(.*?)(GU.*?TACTAAC.{20,40}AG) > > myboost.cpp114 ATG(...)*?(TAG|TAA|TGA) > > > > ( progam hangs in my code or had been core dumping in boost::regex ) > >What is the text you are matching against? If you can give me a concrete >example I can test it here, but "it hangs" isn't very useful I'm afraid ;-) > >John. > >_______________________________________________ >Boost-users mailing list >Boost-users(a)lists.boost.org >http://lists.boost.org/mailman/listinfo.cgi/boost-users _________________________________________________________________ Help yourself to FREE treats served up daily at the Messenger Café. Stop by today! http://www.cafemessenger.com/info/info_sweetstuff2.html?ocid=TXT_TAGHM_OctH…

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[Iostreams] Issue with mapped_file
by JD 04 Oct '07

04 Oct '07

Hello, There is something I don't get with mapped_file from the IOStreams library. Here is an example: // Code snippet #include <iostream> #include <boost/iostreams/device/mapped_file.hpp> #include <boost/iostreams/stream.hpp> using namespace boost::iostreams; int main(int argc, char **argv) { if (argc != 2) return 1; try { stream <mapped_file_sink> out; mapped_file_params p(argv[1]); p.new_file_size = 1024 * sizeof (char); out.open(mapped_file_sink(p)); } catch (const std::exception &e) { std::cout << e.what() << std::endl; return 2; } return 0; } // Code snippet When compiled, the execution goes like: c:\>test_shmem somefile c:\>test_shmem somefile failed setting file size: The handle is invalid. I tried without the new_file_size, I tried with a mapped_file... Is there something I don't get? Why are we not able to open a file that already exist? Thanks for your help. JD

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[smart_ptr] shared_ptr clean-up failure
by Robbie Morrison 04 Oct '07

04 Oct '07

Hi all -- hope someone can help, many TIA -- Robbie Intro This relates to the Boost.Smart_ptr library. The example code (see below) fails when a boost::shared_ptr is used, but not when a raw pointer is substituted. This posting probably highlights some key misunderstanding on my part. Perhaps someone can explain where I went wrong. As a long shot, it could be that the Boost.Ref library can offer something useful. Problem I want to pass in an existing UDT (user-defined type) by reference to a second UDT during construction. I figured it would be better to hold this reference in a smart pointer rather than a raw pointer. The following stripped-down code mimics this process, but passes in an int (a fundamental type) instead for reasons of simplicity. The example works fine with a raw pointer, but not a boost::shared_ptr (or std::auto_ptr or boost::scoped_ptr or std::tr1::shared_ptr). I checked in Becker (2007) ("C++ standard library extensions") and Karlsson (2006) ("Beyond the C++ standard library") regarding Boost.Smart_ptr's, but could not see anything useful. 'frag-pass-by-ref_03.cc' was the name of my program. Test environment - Boost release 1.34.1 dated 24-Jul-2007 (source build) - GNU GCC 4.1.2 compiler (using -Wall -Weffc++ -pedantic) - Linux Ubuntu 6.10 operating system (now superseded by 7.04) - run-time memory checking with valgrind version "valgrind-3.2.0-Debian" - laptop is Toshiba Tecra A2 330, new 2004, 1.4GHz Intel Celeron M Error messages (normal run-time) destroying a MyClass *** glibc detected *** ./frag-pass-by-ref_03: free(): invalid pointer: 0xbfcd12dc *** ======= Backtrace: ========= /lib/tls/i686/cmov/libc.so.6[0xb7d8a8bd] /lib/tls/i686/cmov/libc.so.6(__libc_free+0x84)[0xb7d8aa44] /usr/lib/libstdc++.so.6(_ZdlPv+0x21)[0xb7f3afc1] ./frag-pass-by-ref_03(__gxx_personality_v0+0x3d3)[0x8048baf] ./frag-pass-by-ref_03[0x8048c96] ./frag-pass-by-ref_03(__gxx_personality_v0+0x274)[0x8048a50] ./frag-pass-by-ref_03(__gxx_personality_v0+0x29e)[0x8048a7a] ./frag-pass-by-ref_03(__gxx_personality_v0+0x2ba)[0x8048a96] ./frag-pass-by-ref_03[0x8048cd4] ./frag-pass-by-ref_03(__gxx_personality_v0+0x195)[0x8048971] /lib/tls/i686/cmov/libc.so.6(__libc_start_main+0xdc)[0xb7d398cc] ./frag-pass-by-ref_03(__gxx_personality_v0+0x65)[0x8048841] ======= Memory map: ======== (remainder omitted) Error messages (under valgrind) destroying a MyClass ==23254== Invalid free() / delete / delete[] ==23254== at 0x4020CC7: operator delete(void*) (vg_replace_malloc.c:244) ==23254== by 0x8048BAE: void boost::checked_delete<int>(int*) (checked_delete.hpp:34) ==23254== by 0x8048C95: boost::detail::sp_counted_impl_p<int>::dispose() (sp_counted_impl.hpp:79) ==23254== by 0x8048A4F: boost::detail::sp_counted_base::release() (sp_counted_base_gcc_x86.hpp:145) ==23254== by 0x8048A79: boost::detail::shared_count::~shared_count() (shared_count.hpp:205) ==23254== by 0x8048A95: boost::shared_ptr<int>::~shared_ptr() (shared_ptr.hpp:131) ==23254== by 0x8048CD3: MyClass::~MyClass() (frag-pass-by-ref_03.cc:21) ==23254== by 0x8048970: main (frag-pass-by-ref_03.cc:31) ==23254== Address 0xBE8944FC is on thread 1's stack (error summary omitted) 8< ------------------------------------------- #include <iostream> // standard io #include <boost/shared_ptr.hpp> // Boost shared pointer class MyClass { public: MyClass (int& i) // & indicates pass-by-reference : d_int(&i) { } // & is address-of operator ~MyClass() { std::cout << "destroying a MyClass" << std::endl; } private: boost::shared_ptr<int> d_int; // shared pointer FAILS // int* d_int; // raw pointer works }; int main() { int myint(2); // simple integer MyClass myclass(myint); // constructor call return 0; } ------------------------------------------- >8 --- Robbie Morrison PhD student -- policy-oriented energy system simulation Institute for Energy Engineering (IET) Technical University of Berlin (TU-Berlin), Germany [from IMAP client]

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boost-users: boost enable_if
by chun ping wang 04 Oct '07

04 Oct '07

template <typename T> bool boost::pseudoprime(const T& n, const T& k) { typedef boost::operators<T> operatorT; BOOST_STATIC_ASSERT(is_integral<T>::value); // static assert 1. BOOST_STATIC_ASSERT((is_base_of<operatorT, T>::value)); // static assert 2. BOOST_ASSERT (n > T(2) && n % T(2) != 0); return modular_expo(k, n-1, n) != T(1) % n ? true : false; } now in vistual studio 2005 sp1 and visual studio 2008 beta the part "is_base_of<operatorT, T>::value" does not work if T happens to be an int or long due to "error C2803: 'operator --' must have at least one formal parameter of class type". I want to use enable_if to enable the STATIC_ASSERT only if T is NOT an arithmetic type for static assert 2. How would i go about doing that?

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(no subject)
by Mark Beinker 04 Oct '07

04 Oct '07

Hi, I was trying to use the boost interval class using g++ under cygwin, but unfortunately, I have trouble to use the exp function. The following code: #include <iostream> #include <cmath> #include <boost/numeric/interval.hpp> #define DOUBLE boost::numeric::interval<double> int main(int argc, char** argv) { DOUBLE x(4,5); std::cout.precision(19); DOUBLE res = exp(x); std::cout<<'['<<res.lower()<<", "<<res.upper()<<']'<<std::endl; return 0; } generates the following compile error: /usr/include/boost/numeric/interval/transc.hpp: In function `boost::numeric::interval<T, Policies> boost::numeric::exp(const boost::numeric::interval<T, Policies>&) [with T = double, Policies = boost::numeric::interval_lib::policies<boost::numeric::interval_lib::rounded_math<double>, boost::numeric::interval_lib::checking_strict<double> >]': itest.cpp:14: instantiated from here /usr/include/boost/numeric/interval/transc.hpp:34: error: 'struct boost::numeric::interval_lib::rounded_math<double>' has no member named 'exp_down' itest.cpp:14: instantiated from here /usr/include/boost/numeric/interval/transc.hpp:34: error: 'struct boost::numeric::interval_lib::rounded_math<double>' has no member named 'exp_up' I use boost version 1.34.1. Any idea why this doesn't work? Regards, Mark

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