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[Units][Interval] Using both together
by Anubis 03 Jul '09

03 Jul '09

Hello all! First let me congratule Matthias and Steven for the great units library. Just recently I have kicked out my own attempt at something like it and switched to boost::units. However I ran into trouble using both boost::units and boost::interval because a single int cannot be static casted to a quantity. So one could either provide a function like: static boost::units::quantity<Unit,Y> quantity(int aValue) { boost::units::quantity<Unit,Y>::from_value(aValue); } Probably not the best idea as any value would get casted to a quantity without notice, therefore totally ruining the concept of from_value. Or as I have implemented a specific checking policy for boost::interval: #include <boost/numeric/interval.hpp> //! The checking policy for boost::interval, if it uses boost::unit /*! Look into boost/numeric/interval/checking.hpp to see other possible base checking policies for template parameter Checking */ namespace boost { namespace units { namespace interval_support { template<class T, class Checking = boost::numeric::interval_lib::checking_base<T> > struct checking_base : Checking { static T empty_lower() { return (std::numeric_limits<T>::has_quiet_NaN ? std::numeric_limits<T>::quiet_NaN() : T::from_value(1)); } static T empty_upper() { return (std::numeric_limits<T>::has_quiet_NaN ? std::numeric_limits<T>::quiet_NaN() : T::from_value(0)); } }; }}} And actually use it like this: #include <boost/units/interval_support.hpp> // or whichever name typedef boost::numeric::interval_lib::change_checking< boost::numeric::interval<MY_QUANTITY_TYPE>, boost::units::interval_support::checking_base<MY_QUANTITY_TYPE> >::type my_unit_interval_type; HTH to easily use boost::units and boost::interval in the future, Thomas Taylor

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Re: [Boost-users] [smart_ptr] weak_ptr / shared_ptr interaction
by Alexander Heinrich 03 Jul '09

03 Jul '09

> Both s1 and s2 should now have use_count of 2 at this point, since there > are 2 shared_ptrs sharing ownership of the same pointee. > > The post-condition expression is correct; the value of r.use_count() > was changed by the construction of the new shared_ptr. Thanks for your reply. So you're saying that the behavior of shared_ptr is correct (perfectly fine with me). But then I have to say, that the documentation of shared_ptr located under http://www.boost.org/doc/libs/1_39_0/libs/smart_ptr/shared_ptr.htm#construc… is wrong, because it says that if you construct a shared_ptr from a weak_ptr (!) the use_count will *not* change.

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Problems with De/Serializing data structures with dll
by Grimm 03 Jul '09

03 Jul '09

Hi, I'm quite noob with boost and I wrote a little test program to test how boost handles serialization of data structures and deserializing the data in dll-plug-in. ( In this case only linked list of BaseImplementation objects, but if I got everything OK more complex structures is need to be serialized). It seems that I have(surprisingly) some problems with de/serializing list properly maybe cause of m_next pointers. I've read the documentation, but not have found help for this issue. Here's some relevant parts of my code ( I know It's a bit ugly, but hey! It's only for test purposes :) : Base.h: /* Abstract base class declaration of objects in linked list*/ #ifndef BASE_H #define BASE_H #include <string> #include <iostream> #include <boost/serialization/assume_abstract.hpp> class Base { public: Base(){} virtual ~Base(){} virtual void setID(const int a_id) =0; virtual const int getID() const =0; virtual void setValue( const double a_value ) =0; virtual const double getValue() const =0; virtual void setDescription( const std::string a_desc ) =0; virtual const std::string getDescription() const =0; virtual void setNext( Base* a_next ) =0; virtual Base* getNext() =0; //Operation - prints some information regarding the object virtual void print()const =0; private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { } }; BOOST_SERIALIZATION_ASSUME_ABSTRACT(Base) #endif ###################################### BaseImplementation.h: //Implementation of Base-class (cells of linked list) #ifndef BASEIMPLEMENTATION_H #define BASEIMPLEMENTATION_H #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> //#include <boost/serialization/export.hpp> #include <boost/serialization/base_object.hpp> #include <boost/serialization/utility.hpp> #include "Base.h" class BaseImplementation : public Base { public: //Constructor & Destructor BaseImplementation(); BaseImplementation( int a_id ); ~BaseImplementation(); //setter & getter virtual void setID( const int a_id ); virtual const int getID() const; virtual void setValue( const double a_value ); virtual const double getValue() const; virtual void setDescription( const std::string a_desc ); virtual const std::string getDescription() const; virtual void setNext( Base* a_next ); virtual Base* getNext(); //Operation - print virtual void print() const; private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & boost::serialization::base_object<Base>(*this); ar & m_id; ar & m_value; ar & m_desc; //THIS SEEMS TO BE THE PROBLEM!!! ar & m_next; } int m_id; double m_value; std::string m_desc; Base* m_next; }; //BOOST_CLASS_EXPORT_GUID(BaseImplementation, "base_impl") #endif ############################################### main program: // PluginTest.cpp : Defines the entry point for the console application. #include "stdafx.h" #include "PluginInterface.h" #include "BaseImplementation.h" #include <iostream> #include <fstream> #include <ctime> #include <cstdio> int _tmain(int argc, _TCHAR* argv[]) { std::remove("serialized.plop"); ...foo... ...foo.. ...foo.. //--Serialization-------------------------------------------------- std::ofstream ofs("serialized.plop"); boost::archive::text_oarchive oa(ofs); BaseImplementation* myObject = NULL; Base* first = NULL; BaseImplementation* prev = NULL; Base* tmp = NULL; //starting point of time consumption calc. start = clock(); //Let's create linked list of 114 instances of //BaseImplementation for dll to deserialize for(int i=0; i < 114; i++) { myObject = new BaseImplementation(); //sets the next cell of the list if(prev) { prev->setNext(myObject); } //first cell of linked list else { first = myObject; tmp =myObject; } //sets the data for object myObject->setID( i ); myObject->setValue( 0.5 +(double)i ); myObject->setDescription("This is object"); prev = myObject; } //The serialization itself oa.register_type(static_cast<BaseImplementation *>(tmp)); for(int i=0; i < 114; i++) { oa << tmp; tmp = tmp->getNext(); //oa << *tmp; } //oa << first; ofs.close(); //Deallocates created & serialized objects for(int i=0; i < 114; i++) { tmp = first->getNext(); delete first; first =tmp; } //stop time consumption calc. stop = clock(); //time consumption of serialization long serializationTime = ( stop - start ); //---Serializatio ends here----------------------------------------- //---Deserialization------------------------------------------------ //start the clock start = clock(); //Deserializes the linked list created above for dll-plugin thePlugin->load("serialized.plop"); //stop the clock stop = clock(); //time consumption of deserialization long deserializationTime = ( stop - start ); //Prinst some deserialized data thePlugin->print(50); std::cout <<"Serializations takes: " <<serializationTime <<" ms" <<std::endl; std::cout <<"Deserialization takes: " <<deserializationTime <<" ms" <<std::endl; ########################################################## Definition of thePlugin class: #include ".\cmyplugin.h" cMyPlugin::cMyPlugin() : cIHAPlugin() { m_name = "My plugin!"; m_description = "A plugin which is located in DLL!"; BaseImplementation* m_baseImpl = NULL; } cMyPlugin::~cMyPlugin() { } bool cMyPlugin::install(cIHAPluginCoreInterface* a_pluginCore) { std::cout << "installing plugin.. "; if( !a_pluginCore ) { std::cout << "failed!\n"; return false; } std::cout << "success.\n"; return true; } /*! \brief Gets the plugin name. \return The plugin name. */ const char* cMyPlugin::getName() { return m_name.c_str(); } /*! \brief Gets the plugin description. \return The plugin description. */ const char* cMyPlugin::getDescription() { return m_description.c_str(); } const int cMyPlugin::getNumber() { return m_baseImpl->getID(); } void cMyPlugin::load(std::string file) { //opens archive std::ifstream ifs(file.c_str()); boost::archive::text_iarchive ia(ifs); ia.register_type<BaseImplementation>(); //this doesn't handle pointers to next cell in list ia >> m_baseImpl; ifs.close(); } void cMyPlugin::print(int a_index) { m_first =m_baseImpl; Base* tmp =m_first; if( !m_first ) { std::cout << "ULTIMATE ERROR!!" << std::endl; return; } else { std::cout <<"--- This is value(double) of first cell: "; std::cout << m_first->getValue() <<" ---" <<std::endl; std::cout <<"--- This is value(double) of second cell: "; std::cout <<m_first->getNext()->getValue() <<" ---" <<std::endl; } for(int i=0; i < 114; i++ ) { if(i == a_index ) { tmp->print(); break; } tmp =tmp->getNext(); } } ################################################## Ok, this works still fine with 114 or less instances on the list, but when I try to do this with more than 114 instances it fails on line: oa << tmp; when it's called for first time. Error Message: "Unhandled exception at 0x1029dfdc (msvcr90d.dll) in SerializationTest.exe: 0xC00000FD: Stack overflow." I had to implement the deserialization in dll's load()-method cause it worked even worse with Serialize(...) used in documentation/examples I use Visual Studio 2008 and boost1.38 by the way. I "solved" this problem by not de/serializing the next pointer(for linked list) and constructed(set the next pointers) the list with own hands while deserializing. But thats possible only cause of simple structure of linked list and it will not work with more complex structures. Any ideas what I'm doing wrong in code I pasted above and how I get it work? And is serialization of tree-like data structures even possible with dlls involved? Thank you! ps: BOOST_CLASS_EXPORT_GUID() macro which is now commented away caused some weird linking errors. -- View this message in context: http://www.nabble.com/Problems-with-De-Serializing-data-structures-with-dll… Sent from the Boost - Users mailing list archive at Nabble.com.

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[smart_ptr] weak_ptr / shared_ptr interaction
by Alexander Heinrich 03 Jul '09

03 Jul '09

Hi @ boost-users. The documentation of shared_ptr states the following: <quote> template<class Y> explicit shared_ptr(weak_ptr<Y> const & r); Effects: Constructs a shared_ptr that shares ownership with r and stores a copy of the pointer stored in r. Postconditions: use_count() == r.use_count(). </quote> Now I experienced some odd behavior with the following piece of code: <code> boost::shared_ptr<int> s1(new int(42)); // use_count == 1 boost::weak_ptr<int> w(s1); // use_count == 1 boost::shared_ptr<int> s2(w); // use_count == 2 (expected use_count == 1) boost::shared_ptr<int> s3 = s2; // use_count == 3 (not sure what to expect here...) </code> 1) According to the documentation use_count should still be 1 after instantiating s2, but it is 2. Or did I misinterpret the docs? 2) Independent of whether instantiating s2 increments the use_count or not, I am unsure if assigning (or copying) a shared_ptr that was constructed from a weak_ptr should increment the use_count (see s3). I'd appreciate any comments on this. Best regards, Alexander

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[Spirit] chset_p
by Commander Pirx 03 Jul '09

03 Jul '09

Hi all, I've detected a strange behavior of Spirit using (VC9SP1). I assume that chset_p( "-_!#$%&*+|~" ) and chset_p( "!#$%&*+-_|~" ) are identical. I've only changed the order of the characters a little bit. But when i'm trying to parse a string like "abcd-edfg: " the parser eats the ':' sign but shouldn't. Examples here: token_ = alnum_p | chset_p( "-_!#$%&*+|~" ); // the line above works fine token_ = alnum_p | chset_p( "!#$%&*+-_|~" ); // here the ':' sign will be consumed! Thanx.

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[TypeTraits] is_base_of behavior
by Ioannis Papadopoulos 03 Jul '09

03 Jul '09

Hi, I'm getting different behaviours using is_base_of on different compilers (tested with gcc, icc, xlc). #include <boost/type_traits.hpp> #include <boost/static_assert.hpp> struct A { }; struct B : public A { }; int main() { // Compile fine under all compilers BOOST_STATIC_ASSERT( (boost::is_base_of<A,A>::value) ); // all fail in xlC 10.1, work fine in gcc 4.3-4.4 and icc 11 BOOST_STATIC_ASSERT( (boost::is_base_of<A,const A>::value) ); BOOST_STATIC_ASSERT( (boost::is_base_of<A,volatile A>::value) ); BOOST_STATIC_ASSERT( (boost::is_base_of<A,const volatile A>::value) ); // Compile fine under all compilers BOOST_STATIC_ASSERT( (boost::is_base_of<A,B>::value) ); BOOST_STATIC_ASSERT( (boost::is_base_of<A,const B>::value) ); BOOST_STATIC_ASSERT( (boost::is_base_of<A,volatile B>::value) ); BOOST_STATIC_ASSERT( (boost::is_base_of<A,const volatile B>::value) ); return 0; } Thanks

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One common mutex and lock to rule them all
by Ryan McConnehey 03 Jul '09

03 Jul '09

Are there plans to provide a command mutex and lock? I know there are versions in both the thread and interprocess library. I'm sure each library developed their own as the library was being created. I've seen users ask about different mutexes and lock before and usually they are directed to either of these libraries. It would seem, from a user perspective, that a more central location for mutexes and lock would be helpful. Possibly in it's own header library. Is there a plan to do this in the future? Ryan

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[Filesystem] API questions
by Alan M. Carroll 02 Jul '09

02 Jul '09

I am trying to use Boost.Filesystem and have run in to some issues with the API which may be actual problems or a lack of understanding on my part. 1) What is the generic way to create current directory and parent directory relative paths, e.g. "." and ".."? Currently for current directory I use boost::filesystem::path(boost::filesystem::path::string_type(1,boost::filesystem::slash<boost::filesystem::path>::value)) which is a bit verbose. Parent directory relative path is the same with '2' instead of '1'. Further, it presumes that string_type has a constructor taking a repeat count and a character which may not be true in all cases. I would define these functionally as path instances which, if passed to current_path, would stay in the same directory or move to the parent directory respectively. Is this usage too file system specific to be included in the library? Is there a superior way to create such paths? 2) Why isn't there a path constructor / generator which takes a pair of path element iterators? E.g. like path make_path(path::iterator x, path::iterator y) { path zret; for ( ; x != y ; ++x ) zret /= *x; return zret; } 3) I tried to write my own templated make_path but I don't see how to either use the path class as the template parameter or compute the path class from its iterator. That is, I want to use path::iterator x,y; // set somehow path p = make_path(x,y); Implemetation 1: template < typename Path > Path make_path(Path::iterator x, Path::iterator y) { ... } This fails because Path can not be deduced from the use of Path::iterator instances. Implementation 2: template < typename PathIter> ??? make_path(PathIter x, PathIter y) {...} I don't see how to specify the return type given the type of an iterator. I think it would be reasonable to put this in the iterator class typedef boost::BOOST_FILE_SYSTEM_NAMESPACE::basic_path<String, Traits> path_type; which would solve my problem. I was able to make it work with VC9 by adding this to the iterator definition in path.hpp typedef path_type path_type; // import from enclosing scope for clients but I don't know how portable that is. 4) My actual goal is to write the function path between(path here, path there) which returns a path such that after current_path(here); current_path(between(here,there)); this returns true equivalent(current_path(), there); and where the returned path is as relative as possible. This is very handy for file generation to generate # include "../inc/thing.h" instead of # include "C:/Documents and Settings/amc/view/main/inc/thing.h" If there is already an easy way to do that, I would be happy to be so informed. Thanks.

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Support of Pretty print
by Mario Chacon 02 Jul '09

02 Jul '09

Hello: Is is possible that boost have gdb pretty prints??.. It's works great with std objects, it will be awesome if boost have it too!! Salu2... masch...

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problems using serialization/export.hpp
by Andrew Michael Levin 02 Jul '09

02 Jul '09

I am having problems compiling the following file called save_a.cc. #include "save_a.hh" #include <string> #include <fstream> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/serialization/export.hpp> BOOST_IS_ABSTRACT(space::A) BOOST_CLASS_EXPORT(space::A) BOOST_CLASS_EXPORT(space::B) using namespace std; namespace space { void save(const A* _a, const string& _filename) { std::ofstream ofs(_filename.c_str()); OARCHIVE oa(ofs); oa & _a; ofs.close(); } } The errors that I get are as follows (I cut them off because they are a lot of them): [ 87%] Building CXX object src/shared/CMakeFiles/cryssmexlib.dir/test/save_a.o cd "/home/My Name/cryssmex/src/shared" && /usr/bin/c++.exe -Dcryssmexlib_EXPORTS -I/usr/include/boost-1_33_1 -I"/home/My Name/cryssmex/cryssmex/src/shared" -Wall -o CMakeFiles/cryssmexlib.dir/test/save_a.o -c "/home/My Name/cryssmex/cryssmex/src/shared/test/save_a.cc" /usr/include/boost-1_33_1/boost/serialization/export.hpp: In static member function `static void boost::archive::detail::guid_initializer<T>::export_register(const char*) [with T = space::A]': /usr/include/boost-1_33_1/boost/serialization/export.hpp:155: instantiated from `boost::archive::detail::guid_initializer<T>::guid_initializer(const char*) [with T = space::A]' /home/My Name/cryssmex/cryssmex/src/shared/test/save_a.cc:9: instantiated from here /usr/include/boost-1_33_1/boost/serialization/export.hpp:146: error: incomplete type `boost::serialization::extended_type_info_null<space::A>' used in nested name specifier /usr/include/boost-1_33_1/boost/serialization/export.hpp: In static member function `static void boost::archive::detail::guid_initializer<T>::export_register(const char*) [with T = space::B]': /usr/include/boost-1_33_1/boost/serialization/export.hpp:155: instantiated from `boost::archive::detail::guid_initializer<T>::guid_initializer(const char*) [with T = space::B]' /home/My Name/cryssmex/cryssmex/src/shared/test/save_a.cc:10: instantiated from here /usr/include/boost-1_33_1/boost/serialization/export.hpp:146: error: incomplete type `boost::serialization::extended_type_info_null<space::B>' used in nested name specifier /usr/include/boost-1_33_1/boost/archive/detail/oserializer.hpp: In static member function `static void boost::archive::detail::save_pointer_type<Archive, TPtr>::save(Archive&, const T&, const boost::archive::detail::basic_pointer_oserializer*) [with T = space::A, Archive = boost::archive::text_oarchive, TPtr = const space::A*]': /usr/include/boost-1_33_1/boost/archive/detail/oserializer.hpp:467: instantiated from `static void boost::archive::detail::save_pointer_type<Archive, TPtr>::invoke(Archive&, TPtr) [with Archive = boost::archive::text_oarchive, TPtr = const space::A*]' /usr/include/boost-1_33_1/boost/archive/detail/oserializer.hpp:536: instantiated from `void boost::archive::save(Archive&, const T&) [with Archive = boost::archive::text_oarchive, T = const space::A*]' /usr/include/boost-1_33_1/boost/archive/basic_text_oarchive.hpp:78: instantiated from `void boost::archive::basic_text_oarchive<Archive>::save_override(T&, int) [with T = const space::A* const, Archive = boost::archive::text_oarchive]' /usr/include/boost-1_33_1/boost/archive/detail/interface_oarchive.hpp:78: instantiated from `Archive& boost::archive::detail::interface_oarchive<Archive>::operator<<(T&) [with T = const space::A* const, Archive = boost::archive::text_oarchive]' /usr/include/boost-1_33_1/boost/archive/detail/interface_oarchive.hpp:86: instantiated from `Archive& boost::archive::detail::interface_oarchive<Archive>::operator&(T&) [with T = const space::A*, Archive = boost::archive::text_oarchive]' /home/My Name/cryssmex/cryssmex/src/shared/test/save_a.cc:18: instantiated from here /usr/include/boost-1_33_1/boost/archive/detail/oserializer.hpp:438: error: invalid use of undefined type `struct boost::serialization::extended_type_info_null<space::A>' /usr/include/boost-1_33_1/boost/serialization/type_info_implementation.hpp:26: error: declaration of `struct boost::serialization::extended_type_info_null<space::A>' /usr/include/boost-1_33_1/boost/archive/detail/oserializer.hpp:439: error: invalid use of undefined type `struct boost::serialization::extended_type_info_null<space::A>' /usr/include/boost-1_33_1/boost/serialization/type_info_implementation.hpp:26: error: declaration of `struct boost::serialization::extended_type_info_null<space::A>' /usr/include/boost-1_33_1/boost/archive/detail/oserializer.hpp:439: error: `save' is not a member of `<declaration error>' /usr/include/boost-1_33_1/boost/archive/detail/oserializer.hpp: In static member function `static const boost::archive::detail::basic_pointer_oserializer* boost::archive::detail::save_pointer_type<Archive, TPtr>::abstract<T>::register_type(Archive&) [with T = const space::A, Archive = boost::archive::text_oarchive, TPtr = const space::A*]': /usr/include/boost-1_33_1/boost/archive/detail/oserializer.hpp:360: instantiated from `static const boost::archive::detail::basic_pointer_oserializer* boost::archive::detail::save_pointer_type<Archive, TPtr>::register_type(Archive&, T&) [with T = const space::A, Archive = boost::archive::text_oarchive, TPtr = const space::A*]' /usr/include/boost-1_33_1/boost/archive/detail/oserializer.hpp:460: instantiated from `static void boost::archive::detail::save_pointer_type<Archive, TPtr>::invoke(Archive&, TPtr) [with Archive = boost::archive::text_oarchive, TPtr = const space::A*]' /usr/include/boost-1_33_1/boost/archive/detail/oserializer.hpp:536: instantiated from `void boost::archive::save(Archive&, const T&) [with Archive = boost::archive::text_oarchive, T = const space::A*]' /usr/include/boost-1_33_1/boost/archive/basic_text_oarchive.hpp:78: instantiated from `void boost::archive::basic_text_oarchive<Archive>::save_override(T&, int) [with T = const space::A* const, Archive = boost::archive::text_oarchive]' /usr/include/boost-1_33_1/boost/archive/detail/interface_oarchive.hpp:78: instantiated from `Archive& boost::archive::detail::interface_oarchive<Archive>::operator<<(T&) [with T = const space::A* const, Archive = boost::archive::text_oarchive]' /usr/include/boost-1_33_1/boost/archive/detail/interface_oarchive.hpp:86: instantiated from `Archive& boost::archive::detail::interface_oarchive<Archive>::operator&(T&) [with T = const space::A*, Archive = boost::archive::text_oarchive]' /home/My Name/cryssmex/cryssmex/src/shared/test/save_a.cc:18: instantiated from here ... ... Any idea what the problem is? Thanks.

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