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

[libboost_mpi-vc90-mt-gd-1_40 . lib]Where can I get this library?
by Juliet Villanueva 27 Jan '10

27 Jan '10

Hi: I am trying to configure MPI boost, when you finish all the steps that come within the documentation, and try to compile a simple example, visual compiler tells me that the library lacks libboost_mpi-vc90-mt-gd-1_40 . lib, which is not where you get, I already have installed JAM on my computer, along with the installation of MPI and MPICH2 Boost, recognizes all of MPI include, with out any problem, it only takes me that library, I hope I can help. Tania. Encuentra las mejores recetas en Yahoo! Cocina. http://mx.mujer.yahoo.com/cocina/

2 1

help
by sebastian cheung 27 Jan '10

27 Jan '10

where to begin? I think I have downloaded Boost 1_40 zip, not sure how to start anything with it or do useful appplications? Help

3 3

Re: [Boost-users] C++ and quality of software
by Kenneth Laskoski 26 Jan '10

26 Jan '10

I risk keeping on spamming, but anyway, here are some words from inside Google. Sean Parent once worked at Adobe, where it acted as Adobe Source ibraries developer. ASL is a fine library that I often use as a complement to boost. He recently (Oct 2009) wrote in the asl-devel mailing list: <citation> I'm now at Google working on ChromeOS. The Google style guide (adhered to by most of Google) has made it a bit difficult for me to spend too much time on ASL. [...] Some of the more challenging parts are - limited use of Boost, no exception handling, and discouraged copy and assignment. Right now I feel like I'm coding with one hand behind my back </citation> I think that style guide is pretty phased out by now, almost twelve years after the C++98 Standard. Yours, Kenneth

1 0

Thread-safe singleton pattern
by Andrew Chinkoff 26 Jan '10

26 Jan '10

Having considered [ http://www.research.ibm.com/designpatterns/pubs/ph-jun96.txt] I propose singleton implementation. I had attached "singleton.hpp" to this letter. Below is the test program: #include <stdio.h> #include <singleton.hpp> class A : public boost::Singleton<A> { // // Only Singleton class can create and delete us! // SINGLETON_IS_MY_FRIEND; public: void foo(){ printf("foo!\n"); } A(){ printf("A()\n"); } ~A(){ printf("~A()\n"); } }; void main() { // It is not compiled: //A a = A::Instance(); // That is exactly as it should be used: A::Instance().foo(); } Test program outputs: A() foo! ~A() Does Boost community think that boost::Singleton is convenient solution?

2 1

[boost-users][propertytree] How to access xml attributes.
by Germán Diago 26 Jan '10

26 Jan '10

Hello. I've been reading the docs for boost.ptree and I couldn't find how to access xml attributes. I just found how to access the text for the elements. Is it possible to access attributes? Thanks in advance.

1 0

[function] rare crash on destroy
by Igor R 26 Jan '10

26 Jan '10

Hello, In my application I use to "post" a pointer to a dynamically allocated boost::function to a hidden window in the following manner (WinXP, MSVC9.0, 1.41): typedf function<void(void)> Functor; #define AM_FUNCTOR (WM_USER+79) // called from some "worker" thread void post(const Functor &func) { Functor *f = new Functor(func); PostMessage(hWind_, AM_FUNCTOR, 0, reinterpret_cast<LPARAM>(f)); } // Window procedure, called from the window thread LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) { switch(msg) { case AM_FUNCTOR: { Functor *f = reinterpret_cast<Functor *>(lParam); (*f)(); delete f; } //.... } post() is called several times per second. Sometimes - but *very* rarely - the line "delete f" causes a crash (Access violation reading location 0xfeeefef6). The application is compiled with /Ox /GL, linked with /LTCG. What could be wrong with this code? Callstack: function_base.hpp, line 323: functor_manager_common::manage_small(): reinterpret_cast<functor_type*>(&out_buffer.data)->~Functor(); // THIS LINE CRASHES function_base.hpp, line 432: functor_manager::manage(): manager(in_buffer, out_buffer, op, tag_type()); The assembly code looks like this: 100134C9 mov esi,dword ptr [esi+0Ch] 100134CC test esi,esi 100134CE je boost::detail::function::functor_manager_common::manage_small+9Eh 100134D0 mov eax,dword ptr [esi] 100134D2 mov ecx,dword ptr [eax+8] // CRASHES HERE, as eax == 0xfeeefeee 100134D5 push esi 100134D6 call ecx Thanks in advance.

3 6

multi_index_container assertion after crash
by Eli Zakashansky 26 Jan '10

26 Jan '10

Hi, I have an application which uses a persistent multi_index_container (I am using bip::managed_mapped_file && after openning the file I do "container = mappedFile->find_or_construct(...)"). I have an interesting behavior when my process crashes/stopped during massive use of the multi_index_container after the process restarts I don't experience any problems reading or inserting new elements to the container but if I try to erase elements or call mutli_index_container::clear (Debug mode only BOOST_MULTI_INDEX_ENABLE_SAFE_MODE is defined) an assertion pops up (safe_mode::Check_same_owner / safe_mode::Check_valid_iterator). At first I thought that this kind of assertion fails due to concurrency issue, but it is not the case (I verified that this data structure is not accessed from more than one thread at a time, during this time the container is locked). Does anyone has any idea what can cause this situation? Or has a resolution ? Thanks a lot in advance, Eli.

5 16

Tracking down a race condition
by Stephen Torri 26 Jan '10

26 Jan '10

In the logging example I have been working on to learn more about boost threads I have run across what I think is a race condition. If I compile and run this sample program it will sometimes write out an error message to a file. For example: 2010-01-23_16:2:23 (pid=10948 thread_id=0x92ce448) (II) funky Other times I see the file is blank. So can I say conclusively that its a race condition? No. Either what is happening is a race condition where the file is closed before the contents are written to the file or something else is causing the logging message to be written sometimes and not at others. So to recap: --- How can you track down a race condition? --- Can I use 'strace' or 'gdb'? Stephen ------------------------------------------- #include <boost/cstdint.hpp> #include <boost/shared_ptr.hpp> #include <boost/thread/mutex.hpp> #include <boost/thread/condition_variable.hpp> #include <boost/thread/thread.hpp> #include <boost/utility.hpp> #include <boost/thread/once.hpp> #include <boost/scoped_ptr.hpp> #include <boost/type_traits/aligned_storage.hpp> #include <boost/bind.hpp> #include <boost/format.hpp> #include <boost/date_time/posix_time/posix_time.hpp> #include <boost/cstdint.hpp> #include <fstream> #include <sstream> #include <vector> namespace myproject { namespace api { /*! * \brief Trace level constants * \date 2003 * \author Stephen Torri */ class TraceLevel { public: enum Values { NONE = 0, WARN = 10, ERROR = 20, INFO = 30, DEBUG = 40, DETAIL = 50, DATA = 60 }; }; } // namespace api } // namespace myproject namespace myproject { namespace interface { class ITraceable { public: typedef boost::shared_ptr<ITraceable> ptr_t; virtual std::string get_Formatted_String() = 0; virtual boost::uint32_t getLevel() = 0; virtual boost::uint32_t getPID() = 0; virtual boost::thread::id getThreadID() = 0; }; } // namespace interface } // namespace myproject namespace myproject { namespace trace { class StringTraceable : public interface::ITraceable { public: StringTraceable ( boost::uint32_t area, boost::uint32_t level, std::string name ) : m_area ( area ), m_level ( level ), m_name ( name ) { #ifndef WIN32 m_pid = getpid(); #else m_pid = GetCurrentProcessId(); #endif /* WIN32 */ m_thread_id = boost::this_thread::get_id(); } virtual ~StringTraceable(){} virtual std::string get_Formatted_String() { return m_name; } virtual boost::uint32_t getLevel() { return m_level; } virtual boost::uint32_t getPID() { return m_pid; } virtual boost::thread::id getThreadID() { return m_thread_id; } private: boost::uint32_t m_area; boost::uint32_t m_level; boost::uint32_t m_pid; boost::thread::id m_thread_id; std::string m_name; }; template <typename UnsignedType> class NumberTraceable : public interface::ITraceable { public: NumberTraceable ( boost::uint32_t area, boost::uint32_t level, std::string name, UnsignedType line ) : m_area ( area ), m_level ( level ), m_name ( name ), m_line ( line ) { #ifndef WIN32 m_pid = getpid(); #else m_pid = GetCurrentProcessId(); #endif /* WIN32 */ m_thread_id = boost::this_thread::get_id(); } virtual ~NumberTraceable(){} virtual std::string get_Formatted_String() { return m_name; } virtual boost::uint32_t getLevel() { return m_level; } virtual boost::uint32_t getPID() { return m_pid; } virtual boost::thread::id getThreadID() { return m_thread_id; } private: boost::uint32_t m_area; boost::uint32_t m_level; boost::uint32_t m_pid; boost::thread::id m_thread_id; std::string m_name; UnsignedType m_line; }; template <typename T> struct storage_for { boost::aligned_storage<sizeof(T), boost::alignment_of<T>::value> data; }; template <typename T> class Singleton : boost::noncopyable { public: static T& Instance() { boost::call_once ( init, m_flag ); return *m_obj; } static void init () { m_obj.reset ( new T() ); } protected: ~Singleton(){} Singleton(){} private: static boost::scoped_ptr<T> m_obj; static boost::once_flag m_flag; }; } // namespace trace } // namespace trace template <typename T> boost::scoped_ptr<T> myproject::trace::Singleton<T>::m_obj ( 0 ); template <typename T> boost::once_flag myproject::trace::Singleton<T>::m_flag = BOOST_ONCE_INIT; namespace myproject { namespace trace { class Trace_State_Utils { public: static std::string get_Level_String ( boost::uint32_t level ) { // Write message prefix if ( level == api::TraceLevel::WARN ) { return "(WW) "; } else if ( level == api::TraceLevel::ERROR ) { return "(EE) "; } else if ( level == api::TraceLevel::INFO ) { return "(II) "; } else if ( level == api::TraceLevel::DEBUG ) { return "(DEBUG) "; } else if ( level == api::TraceLevel::DETAIL ) { return "(DETAIL) "; } else if ( level == api::TraceLevel::DATA ) { return "(DATA) "; } else { // We should not be here abort(); } } }; /* Idea taken from http://www.codeproject.com/debug/xytrace.asp * (28 Jan 2002 - Xiangyang Liu) * * I have modified this so that we don't use varargs and use constant types */ class Trace_State { public: typedef boost::shared_ptr<Trace_State> ptr_t; Trace_State() : m_file_prefix ( "Trace" ) {} virtual ~Trace_State(); Trace_State ( std::string prefix ); void set_Trace_File_Prefix ( std::string name ); void set_Trace_Level ( boost::uint32_t level ); void set_Trace_Area_Mask ( boost::uint32_t mask ); void open_Trace_File ( void ); std::string get_ID_String ( void ); void close_Trace_File ( void ); boost::uint32_t get_Trace_Level ( void ) const; boost::uint32_t get_Trace_Area_Mask ( void ) const; bool is_Valid_Level ( boost::uint32_t lvl ); bool is_Valid_Area_Mask ( boost::uint32_t mask ); void write_Message ( interface::ITraceable::ptr_t trace ) { // Write ID m_log_stream << boost::format("%s (pid=%d thread_id=" ) % this->get_ID_String() % trace->getPID() << trace->getThreadID() << ") " << std::flush; m_log_stream << Trace_State_Utils::get_Level_String(trace->getLevel()) << trace->get_Formatted_String() << std::endl << std::flush; } private: std::string m_file_prefix; std::ofstream m_log_stream; }; } /* namespace trace */ } /* namespace trace */ namespace myproject { namespace trace { Trace_State::Trace_State( std::string prefix ) : m_file_prefix ( prefix ) {} Trace_State::~Trace_State() { this->close_Trace_File(); } void Trace_State::set_Trace_File_Prefix ( std::string name ) { } bool Trace_State::is_Valid_Level ( boost::uint32_t lvl ) { return true; } bool Trace_State::is_Valid_Area_Mask ( boost::uint32_t ) { return true; } void Trace_State::set_Trace_Level ( boost::uint32_t level ) { } void Trace_State::set_Trace_Area_Mask ( boost::uint32_t mask ) { } void Trace_State::open_Trace_File ( void ) { if ( ! m_log_stream.is_open() ) { // Create file name std::stringstream name; name << boost::format("%s_%s.txt") % m_file_prefix % this->get_ID_String(); std::string file_name = name.str(); m_log_stream.open ( file_name.c_str() ); } } std::string Trace_State::get_ID_String ( void ) { // Create id string std::stringstream name; // Get current time boost::posix_time::ptime now = boost::posix_time::second_clock::local_time(); std::tm tm_ref = boost::posix_time::to_tm ( now ); boost::gregorian::date today = now.date(); name << boost::format ( "%1%_%2%:%3%:%4%" ) % boost::gregorian::to_iso_extended_string ( today ) % tm_ref.tm_hour % tm_ref.tm_min % tm_ref.tm_sec; return name.str(); } void Trace_State::close_Trace_File ( void ) { if ( m_log_stream.is_open() ) { m_log_stream << std::flush; m_log_stream.close(); } } boost::uint32_t Trace_State::get_Trace_Level ( void ) const { return 0; } boost::uint32_t Trace_State::get_Trace_Area_Mask ( void ) const { return 0; } } /* namespace trace */ } /* namespace trace */ namespace myproject { namespace trace { // // Turn Trace into a singleton class that contains a worker thread // - Wait for data // - If data exists then process // - Else wait // Add method for adding a ITraceable object. This will lock the logging vector, add // element then signal the boost condition variable class Trace : public Singleton<Trace> { friend class Singleton<Trace>; public: ~Trace(); static void write_Trace ( boost::uint32_t area, boost::uint32_t level, std::string name ) { interface::ITraceable::ptr_t string_ptr ( new StringTraceable ( area, level, name ) ); Trace::Instance().add_Trace ( string_ptr ); } template <typename UnsignedType> static void write_Trace ( boost::uint32_t area, boost::uint32_t level, std::string format, UnsignedType value ) { interface::ITraceable::ptr_t unsigned_ptr ( new NumberTraceable<UnsignedType> ( area, level, format, value ) ); Trace::Instance().add_Trace ( unsigned_ptr ); } void add_Trace ( interface::ITraceable::ptr_t trace ); void set_Trace_Level ( boost::uint32_t level ); void set_Trace_Area_Mask ( boost::uint32_t mask ); void open_Trace_File (); void close_Trace_File(); private: Trace(); // Worker thread functions void threadMain(); void processTraces(boost::unique_lock<boost::mutex>& lock); // Synchronization variables boost::mutex m_lock; boost::condition_variable m_condition; // Data variables typedef std::vector < myproject::interface::ITraceable::ptr_t > QueueType; QueueType m_queue; // Thread variables boost::shared_ptr<boost::thread> m_thread; bool m_hasWork; // Logging Trace_State m_state; }; } /* namespace trace */ } /* namespace myproject */ namespace myproject { namespace trace { Trace::Trace () : m_hasWork ( true ), m_state ( "Trace" ) { // start thread m_thread = boost::shared_ptr<boost::thread> ( new boost::thread ( boost::bind ( &Trace::threadMain, this ) ) ); } Trace::~Trace() { // stop thread { boost::lock_guard<boost::mutex> lock ( m_lock ); m_hasWork = false; } m_condition.notify_one(); m_thread->join(); } void Trace::add_Trace ( interface::ITraceable::ptr_t trace ) { // lock queue { boost::lock_guard<boost::mutex> lock ( m_lock ); m_queue.push_back ( trace ); } m_condition.notify_one(); } void Trace::threadMain() { boost::unique_lock<boost::mutex> lock ( m_lock ); while ( m_hasWork ) { if ( m_queue.size() == 0 ) { m_condition.wait ( lock ); } else { this->processTraces(lock); } } } void Trace::processTraces(boost::unique_lock<boost::mutex>& lock) { assert ( lock.owns_lock() ); QueueType local_queue ( m_queue.begin(), m_queue.end() ); m_queue.clear(); lock.unlock(); for ( QueueType::iterator pos = local_queue.begin(); pos != local_queue.end(); pos++ ) { myproject::interface::ITraceable::ptr_t trace_obj = (*pos); m_state.write_Message ( trace_obj ); } lock.lock(); } void Trace::set_Trace_Level ( boost::uint32_t level ) { m_state.set_Trace_Level ( level ); } void Trace::set_Trace_Area_Mask ( boost::uint32_t mask ) { m_state.set_Trace_Area_Mask ( mask ); } void Trace::open_Trace_File() { m_state.open_Trace_File(); } void Trace::close_Trace_File() { m_state.close_Trace_File(); } } /* namespace trace */ } /* namespace myproject */ int main ( int, char** ) { namespace trace = myproject::trace; namespace api = myproject::api; trace::Trace::Instance().open_Trace_File(); myproject::interface::ITraceable::ptr_t tmp_ptr ( new trace::StringTraceable( 0, api::TraceLevel::INFO, "funky" ) ); trace::Trace::Instance().add_Trace ( tmp_ptr ); trace::Trace::Instance().close_Trace_File(); }

3 4

[chrono] v0.3.2 New frequency, lifetime and percentage stopwatch_accumulator features
by vicente.botet 26 Jan '10

26 Jan '10

Hi, I have update the Boost.Chrono library with some minor features, a lot of bug fixes, and started the tutorial with some examples of features interesting people since the last version. New Features: * Added overloading for operator/(Integer/Duration) (used to get the frequency) * Added frequency, lifetime and percentage to the stopwatch_accumulator. The default format is "%c times, sum%ss, min%ms, max%Ms, mean%as, frequency%fherzs, lifetime%ls, percentage=%p%\n", where %c : the counter of the number of times the pair start/stop has been called. %s : the sum of the samples of elapsed time between the call to start/stop. %m : the min of the samples of elapsed time between the call to start/stop. %M : the max of the samples of elapsed time between the call to start/stop. %a : the mean of the samples of elapsed time between the call to start/stop. %f : the frequency of calls to start. %l : the lifetime of the stopwatch_accumulator. %p : the percentage of time spent by this stopwatch respect to its lifetime. Bug Fixes * Specific formatters didn't work completly * Replace duration(0) by duration::zero() on template classes. * suspend didn't work: partial_ not initialized neither taken in account by the elapsed function. The library can be downloaded from http://www.boostpro.com/vault/index.php?action=downloadfile&filename=chrono… and the documentation is online on the sandbox http://svn.boost.org/svn/boost/sandbox/chrono/libs/chrono/doc/html/index.ht…. SVN repository http://svn.boost.org/svn/boost/sandbox/chrono. I would like to thanks particularly Andrew Chinkoff for his suggestion of the frequency feature and all those that have tried the library and reported the bugs they found, either on this ML or personally. I would really appreciate if people having the possibility to test on other platforms/compilers report me how the library works. As you can see the library is already on the review schedule, waiting for a review manager and a date for the review. I expect to add yet some features for the review release as thread clocks, and suspensible clocks i.e. clocks that can be suspended/resumed. Any idea for better naming the concepts/classes is welcome. Hoping this release works better for you, Vicente (See below the contents of preceding releases) ----- Original Message ----- From: "vicente.botet" <vicente.botet(a)wanadoo.fr> To: <boost-users(a)lists.boost.org>; <boost(a)lists.boost.org> Sent: Wednesday, January 20, 2010 11:02 PM Subject: [chrono] v0.3.1 Support for wide characters Hi, this new version includes: * Added support for wide characters on formatters. * Added chrono.hpp and stopwatches.hpp header files at the boost level. * Update of the doc taking care of preceding comments. Comments are welcome :) Best, Vicente ----- Original Message ----- From: "vicente.botet" <vicente.botet(a)wanadoo.fr> To: <boost(a)lists.boost.org>; <boost-users(a)lists.boost.org> Sent: Sunday, January 17, 2010 9:14 PM Subject: [chrono] v0.3 New Stopwatch Feature Hi, I'm pleased to announce the new version of the Boost.Chrono library. The implementaton is quite stable; the new interface could suffer of some modifications, renaming, ... as far as you submit some proposals. I would request a formal review soon and I will need a review manager. I know that review managers are hard to find, so if you are interested in the library, please the Review Wizards. The library can be downloaded from http://www.boostpro.com/vault/index.php?action=downloadfile&filename=chrono… and the documentation is online on the sandbox http://svn.boost.org/svn/boost/sandbox/chrono/libs/chrono/doc/html/index.ht…. I've tested it with gcc and MSVC. Previoous version of the library have been testted on Mac, but I'm not able to test this platform. Could someone check if there are some regressions on Mac? New Features: * Process cpu clocks * Independent process cpu clocks for real, user, system process CPU time * Global process cpu clock for real, user, system process CPU time * Stopwatch concept measuring elapsed time between different points in time associated to the operations start, stop, suspend and resume. * stopwatch is a model Stopwatch measuring the elapsed time between the start and the stop operations. * stopwatch_accumulator is a model Stopwatch allowing to accumulate several time samples and give the average, ... * Scoped helper classes allowing to pairwise start/stop operations, suspend/resume and resume/suspend a Stopwatch. * Stopwatch Formatter concept * stopwatch formatter "%ds\n" * stopwatch accumulator formatter "%c times, sum%ss, min%ms, max%Ms, mean%as\n" * time formatter "real %rs, cpu %cs (%p%), user %us, system %ss\n" * digital_time decomposition class separating days, hours,minutes,seconds, nanoseconds from any duration class (looking for a better name) * digital_time formatter "%d days(s) %h:%m:%s.%n\n" * stopwatch_reporter is a convenient generic class reporting elapsed time for the Stopwatch concept. * stopclock<Clock> shortcut stopwatch_reporter<stopwatch<Clcok>> * typeof registration for classes duration and time_point Depreceated Features: * The classes process_times, process_clock, process_timer, timer and run_timer are now deprecated as the preceding additions are more generic. However for backward compatibility they are preserved until inclusion of the library in Boost. Next follows the equivalences: timer<> ~ stopwatch<> process_timer ~ stopwatch<process_cpu_clock> run_timer ~ stopclock<> Bug Fixes * Try to correct warning C4251: 'boost::chrono::run_timer::m_format' : class 'std::basic_string<_Elem,_Traits,_Ax>' needs to have dll-interface to be used by clients of class 'boost::chrono::run_timer', by don't including inlines functions using the std::string m_format. For people that doesn't know it yet, Boost.Chrono library provides: * The C++0x Standard Library's common_type. * The C++0x Standard Library's compile-time rational arithmetic. * The C++0x Standard Library's time utilities, including: * Class template duration * Class template time_point * Clocks: * system_clock * monotonic_clock * high_resolution_clock * typeof registration for classes duration and time_point * Process clocks: * process_real_CPU_clocks, capturing real-CPU times. * process_user_CPU_clocks, capturing user-CPU times. * process_system_CPU_clocks, capturing system-CPU times. * process_cpu_clock, tuple-like class capturing at once real, user-CPU, and system-CPU times. * Stopwatches: * stopwatch, capturing elapsed Clock times. * stopwatch_accumulator, capturing cummulated elapsed Clock times. * scoped helper classes allowing to pairwise start/stop operations, suspend/resume and resume/suspend a Stopwatch. * Stopclocks or Stopwatch reporters: * stopwatch_reporter, convenient reporting of models of Stopwatch results. * stopclock<Clock> shortcut of stopwatch_reporter<stopwatch<Clock>> Best regards, _____________________ Vicente Juan Botet Escribá

1 0

Boost::Asio - blocking read on socket does not disconnect when socket closed from other thread
by Nick Aschberger 25 Jan '10

25 Jan '10

Hi Folks, Boost version is 1.36, OS is linux rhel-4. I have an application with two threads. The secondary thread is a worker thread that manages a boost::asio tcp/ip socket. The worker thread performs blocking reads as per: try { boost::system::error_code error; boost::asio::read(mysocket, boost::asio::buffer(inputbuffer, size_to_read), boost::asio::transfer_all(), error); if(error) { throw boost::system::system_error(error); } } catch(boost::system::system_error se){ // log error here return false; } In the main application thread, in response to the user choosing to close the connection, I do: mysocket.cancel(); mysocket.close(); I would expect the worker thread to return from the blocking boost::asio::read call, with an error. This occurs on windows, but does not happen on the linux build of my app - it never returns from the above call. Why does the second thread never return? What am I doing wrong? I have considered: - implementing a timeout - but I don't want to move to async sockets. - It seems SO_RCVTIMEO, is wrapped by boost::asio::read, so no hope there. - I could kill the thread but that means it isn't cleaned up properly, so that is no good. What am I doing wrong? cheers Nick Aschberger

2 3