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[Serialization - 1.46.1] : Suggestion
by Mathieu Peyréga 03 May '11

03 May '11

Hello, Here is a small feature suggestion : I've been modifying the nvp.hpp file and added after line 142 the following macro definition : // Added by Mathieu Peyréga #define BOOST_SERIALIZATION_BASE_OBJECT_TEMPLATE_NVP(name,templateparameter) \ boost::serialization::make_nvp( \ BOOST_PP_STRINGIZE(name)BOOST_PP_STRINGIZE(templateparameter), \ boost::serialization::base_object<name<templateparameter> >(*this) \ ) // Which enables "easier" serialization for case like the following where the is multiple heritage and one of the base class is a template. Do you think this is the good way to go ? Best regards, Mathieu Peyréga /*************************************************************************************************** Short example of the BOOST_SERIALIZATION_BASE_OBJECT_TEMPLATE_NVP macro ***************************************************************************************************/ class C_Battery : public C_PhysicalElement, public C_GenericDatabaseObject<C_Battery> { public: C_Battery(void); C_Battery(C_Battery const& obj); C_Battery& operator=(C_Battery const& obj); virtual ~C_Battery(void); Boolean operator==(C_Battery const& other) const; Float64 getTensionPerElement(void) const; Float64 getCapacityPerElement(void) const; Float64 getFaradicEfficiency(void) const; Float64 getUnloadDeepness(void) const; Float64 getVolumicInstallationCost(void) const; Float64 getNumberOfCycles(void) const; Float64 getMonthlySelfLosses(void) const; void setTensionPerElement(Float64 const& value); void setCapacityPerElement(Float64 const& value); void setFaradicEfficiency(Float64 const& value); void setUnloadDeepness(Float64 const& value); void setVolumicInstallationCost(Float64 const& value); void setNumberOfCycles(Float64 const& value); void setMonthlySelfLosses(Float64 const& value); void loadFromCSVDatabase(C_CSVFileParser const& parser, Int32 recordIndex); protected: friend class C_GenericDatabaseObject<C_Battery>; Float64 m_TensionPerElement; // Tension par élément en Volts Float64 m_CapacityPerElement; // Capacitée par élément en A*h Float64 m_FaradicEfficiency; // Rendement faradique Float64 m_UnloadDeepness; // Profondeur de décharge Float64 m_VolumicInstallationCost; // Cout d'installation en euro/dm3 Float64 m_NumberOfCycles; // Nombre de cycles à la profondeur autorisée Float64 m_MonthlySelfLosses; // Auto décharge mensuelle friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(C_PhysicalElement); ar & BOOST_SERIALIZATION_BASE_OBJECT_TEMPLATE_NVP(C_GenericDatabaseObject,C_Battery); ar & BOOST_SERIALIZATION_NVP(m_TensionPerElement); ar & BOOST_SERIALIZATION_NVP(m_CapacityPerElement); ar & BOOST_SERIALIZATION_NVP(m_FaradicEfficiency); ar & BOOST_SERIALIZATION_NVP(m_UnloadDeepness); ar & BOOST_SERIALIZATION_NVP(m_VolumicInstallationCost); ar & BOOST_SERIALIZATION_NVP(m_NumberOfCycles); ar & BOOST_SERIALIZATION_NVP(m_MonthlySelfLosses); } }; BOOST_CLASS_VERSION(C_Battery, 1)

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Re: [Boost-users] Thread Safety of shared_ptr
by Kevin Frey 03 May '11

03 May '11

> shared_ptr< Session >* is not a shared ptr, it is a RAW ptr to shared_ptr< Session>. Yes, I know this. The pointer you call the RAW pointer is owned only by one object. It doesn't make the implementation wrong. My issue concerns the addref/decref behaviour that occurs simultaneously within two different threads.

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Re: [Boost-users] Thread Safety of shared_ptr
by 乔志强 03 May '11

03 May '11

shared_ptr< Session >* sp_Session = new shared_ptr< Session >( new Session ); shared_ptr< Session >* is not a shared ptr, it is a RAW ptr to shared_ptr< Session>. So you should: 1. use shared_ptr of shared_ptr: shared_ptr<shared_ptr< Session > > sp_Session ( new shared_ptr< Session >( new Session )) ; 2. or use shared_ptr directly: shared_ptr< Session > sp_Session( new Session ); I think you should use 2. > ------------------------------ > > Message: 7 > Date: Tue, 3 May 2011 10:46:39 +1000 > From: "Kevin Frey" <kfrey(a)hardcat.com> > To: <boost-users(a)lists.boost.org> > Subject: Re: [Boost-users] Thread Safety of shared_ptr > Message-ID: > <95C19A2ED65BF54CB79DF1F9D6A488E0013E3351(a)hcmail1.MEL01.hardcat.com.a > u> > > Content-Type: text/plain; charset="us-ascii" > > > Actually, I am not sure with this statement. Destructor is only called > if shared count reaches zero. I don't think that this can happen, that a > dtor is called in one thread and the other thread is still able to > increment the shared count even from the weak_ptr. I remember reading > weak_ptr's source and saw that it is also protected again such a case. > > > > I have taken the example at face value, but in hindsight the examples > could be a lot better because there is no context to describe the > circumstances of how the shared_ptrs are instantiated. > > > > For example, is p allocated globally, and p2 & p3 allocated at the > beginning of their respective threads? If so, example 4 becomes > meaningless because Thread B cannot force p2 out of scope since it would > only go out of scope once thread A exits, since thread A controls the > scope of p2. If thread B were to force p2 "out of scope" then p2 would > have to be a shared_ptr< >*, dynamically allocated., and subsequently > deleted by Thread B. But it is not represented that way. > > > > Unfortunately none of this helps solve my original question, which given > the direction this thread is proceeding, I will re-state in pseudo-code > that approximates the *actual* situation occurring in my program: > > > > Earlier on: > > > > shared_ptr< Session >* sp_Session = new shared_ptr< Session >( new > Session ); > > > > Dependent_Class* dep = new Dependent_Class( shared_ptr< Session >& > shared_ptr_session ); > > In Dependent_Object::Dependent_Object( ) > > this->sp_Session = new shared_ptr< Session >( shared_ptr_session ); > > Now, simultaneously: > > > > Thread A: > > Dependent_Class* dep2 = new Dependent_Class( shared_ptr< Session>& > shared_ptr_session ); > > In Dependent_Object::Dependent_Object( ) > > this->sp_Session = new shared_ptr< Session >( shared_ptr_session ); > > > > Thread B: > > In Dependent_Class::~Dependent_Class( ): // the cleanup of dep > > delete this->sp_Session; > > > > So, we have: > > > > 1. A shared object (pointed to by a shared_ptr) that is presently > in existence with a reference count of at least 2. > > 2. One thread A creating another shared_ptr to the shared object, > attempting to increment the reference count. > > 3. Another thread B simultaneously destroying a *different* > shared_ptr which is connected to the same underlying shared object, > decrementing the reference count. > > > > Note that the shared object is *not being destroyed* here, just the > reference counts are being manipulated. > > > > Will shared_ptr handle this situation correctly? > > > > Thanks > > > > Kevin > > >

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boost as shared library - linux
by Krzysztof 02 May '11

02 May '11

When I try to use libboost_program_options.so in my program it gives me a message: error while loading shared libraries: libboost_program_options.so.1.46.1: cannot open shared object file: No such file or directory I tried to do the command "ldconfig -n" and substitute to LD_LIBRARY_PATH the dir where it is located - the message remains the same. The boost library directory is in my home folder. How to overcome this? -- Regards Krzysztof J.

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[Test] Compiling libraries for Windows Mobile 6 ARMV4I
by Paul Heil 02 May '11

02 May '11

I would like to be able to use the Boost.Test library for Windows Mobile 6 ARMV4I projects compiled by Visual Studio 2008. I can successfully compile the Boost.Signals, Boost.Thread, Boost.System, and Boost.Random libraries; but Boost.Test uses several functions that aren't available under Windows Mobile even with STLPort 5.2.1. Specifically, these are strerror() and getenv(). The actual compile errors I receive are: /test/impl/cpp_main.ipp(38) : error C2039: 'getenv' : is not a member of '`global namespace'' /test/impl/cpp_main.ipp(38) : error C2873: 'getenv' : symbol cannot be used in a using-declaration /test/impl/cpp_main.ipp(38) : error C2039: 'strerror' : is not a member of '`global namespace'' /test/impl/cpp_main.ipp(38) : error C2873: 'strerror' : symbol cannot be used in a using-declaration /test/impl/execution_monitor.ipp(1306) : error C2039: 'strerror' : is not a member of 'stlpd_std' /test/impl/execution_monitor.ipp(1306) : error C3861: 'strerror': identifier not found /test/impl/cpp_main.ipp(106) : error C2039: 'getenv' : is not a member of 'stlp_std' /test/impl/cpp_main.ipp(106) : error C3861: 'getenv': identifier not found I have seen past postings by other users that have suggested they have supplemented STLPort with these functions (particularly posts relating to VeetoFTC), but I have yet to see an actual example of the code changes necessary to do that. Can anybody suggest the least intrusive way to add this functionality so that I can compile the rest of Boost? Thanks, PaulH

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[phoenix] conditional expression?
by alfC 02 May '11

02 May '11

Hi, Does Phoenix support conditional expression? I know if supports if_ *statements* but it seems that there's is no conditional (expression*. The question what is is the equivalent for "(x>2.)?(1.):(-1.)" in general. For example, I tryed with if_[].else_[] hoping that the statement is used as result but with no luck: #include<boost/phoenix/phoenix.hpp> #include<iostream> using namespace boost::phoenix; using namespace boost::phoenix::arg_names; int main(){ std::clog << (arg1*arg1)(2.) << std::endl; //returns correctly 4 std::clog << (if_(arg1>2.)[val(1.)].else_[val(-1.)])(2.) << std::endl; //syntax error return 0; } The syntax error points that the expression fails to evaluate as a number. Any ideas? -- Thanks, Alfredo usr/include/boost/proto/operators.hpp:79:9: error: forming reference to void if.cpp:8:43: error: no match for ‘operator<<’ in ‘std::clog << boost::phoenix::if_ [with Cond = boost::phoenix::actor<boost::proto::exprns_::basic_expr<boost::proto::tag::greater, boost::proto::argsns_::list2<boost::phoenix::actor<boost ... etc, etc, 100 lines

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[iostreams] Flushing problems with :filtering_ostream
by Bo Jensen 02 May '11

02 May '11

I had some older code which used to work before, but seem to have flushing problems now. The problem is I can not make boost::iostreams::filtering_ostream flush properly. Here is a snippet of my code, which is not compilable in the current form, since I just pulled it out of my own code. Here it goes : /* Helper class for writing gzipped files */ class gzip_sink { public: typedef char char_type; typedef boost::iostreams::sink_tag category; Log &Logger_; /* Logger */ boost::iostreams::filtering_ostream sink_; /* Sink used to push filters */ SlmOfstream outifstr_; /* Write stream to be pushed into sink */ std::wstring name_; /* Store name of attached file */ /* Constructor */ gzip_sink(const wchar_t *filename,Log &logger) SlmExcStartConstructor : Logger_(logger), name_(filename) { /* Open for write */ SlmOpenWriteFile(Logger_, name_.c_str(), outifstr_); /* Push gzip compressor */ sink_.push(boost::iostreams::gzip_compressor()); } SlmExcStopConstructor gzip_sink(const gzip_sink &rhs) SlmExcStartConstructor : Logger_(rhs.Logger_), name_(rhs.name_) { /* Open for write */ SlmOpenWriteFile(Logger_, name_.c_str(), outifstr_); /* Push gzip compressor */ sink_.push(boost::iostreams::gzip_compressor()); } SlmExcStopConstructor void Close() { sink_.reset(); } ~gzip_sink() { sink_.reset(); } /* Write function */ std::streamsize write( const char * s, std::streamsize n ) { /* Push write stream */ /* THIS IS THE HACK !!! WE NEED TO PUSH AND POP EACH TIME OTHERWISE SOME FLUSH IS NOT DONE!! */ sink_.push(outifstr_); sink_.write(s,n); sink_.pop(); return n; } }; I have to push and pop the stream on to the sink each time I write, which should only be done once in the constructor. It is clearly some flushing issue, but I have tried flushing in all places and no luck, any help ? If you think it looks a bit odd, it's because I use it together with boost::iostreams::code_converter<gzip_sink> to be able to use gzip with wide streams.

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[Review] Boost.Convert library, last day
by Edward Diener 02 May '11

02 May '11

This is a reminder that formal review of the Boost.Convert library by Vladimir Batov ends today, May 2. There have only been a few reviews of the library so the library welcomes reviews. If you are one of the people who have been dissatisfied by the perceived limitations of Boost lexical_cast, or have discussed such limitations on Boost mailing lists in the past, please look at the library and give a review of it, as its intent is to offer a greatly enhanced version of lexical_cast as a new library. *************** * Its Purpose * *************** The library builds on the past boost::lexical_cast experience, then takes those conversion-related ideas further to suit better today's applications and programing needs. It still offers simple, minimal interface, familiar conversion behavior and additionally provides: * throwing and non-throwing conversion-failure behavior; * support for the default/fallback value to be returned when conversion fails; * two types of the conversion-failure check - basic/simple and better/safe; * formatting support based on the standard std::streams and std::stream-based manipulators (like std::hex, std::scientific, etc.); * support for different locales; * support for boost::range-compliant char and wchar_t-based containers; * no DefaultConstructibility requirement for the Target/Destination type; * consistent framework to uniformly incorporate any type-to-type conversions, extensibility and additional room to grow. With its present support for string-to-type and type-to-string conversions it is an essential tool for applications making extensive use of configuration or MS-Windows-Registry-style files or having to process/prepare considerable amounts of data in, say, XML, etc. More so, it is easily extendable to accommodate, specialize and uniformly deploy new user-defined type-to-type conversions. ******************* * Where to get it * ******************* The Boost Vault is accesible again after being down for most of the week, so you can get the library from the Boost Vault at http://www.boostpro.com/vault/index.php?action=downloadfile&filename=boost-… You can also get the library, using Subversion, from https://svn.boost.org/svn/boost/sandbox/convert. The HTML documentation is part of the distribution and can be found at libs/convert/index.html in the distribution above. ******************** * Writing a review * ******************** The reviews and all comments should be submitted to the developers list, and the email should have "[convert] Review" at the beginning of the subject line to make sure it's not missed. Please explicitly state in your review whether the library should be accepted. The general review checklist: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? And finally, every review should answer this question: - Do you think the library should be accepted as a Boost library? Be sure to say this explicitly so that your other comments don't obscure your overall opinion. Edward Diener, Review Manager

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Re: [Boost-users] [Multi-Index] Categorised Container
by Hossein Haeri 02 May '11

02 May '11

Hi Joaquín, > multi_index_conainer< > T, > ordered_non_unique< > composite_key< > T, > member<T,category_t,&T::category>, > member<T,second_type,&T::second> > > > >, > ordered_non_unique<...> > > my_container; > > Now, if you do an equal_range on a category elements will indeed be > sorted by the second member. Right. Here is a better formulated question then: Let's say c1 is an object of type category_t. When I apply equal_range for c1, will I get my desired range in log(n) time (where n == my_container.size())? Or, will I get it in O(1) for the elements are already stored in a category-by-category manner? TIA, --Hossein

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Fwd: Re: [Review] Boost.Convert library, last 3 days
by Edward Diener 01 May '11

01 May '11

I am forwarding this message sent directly to me as the review manager of the Boost Convert library review. I have removed the forwarding information to protect privacy. Hi Edward, I am by no means an expert in library design, so perhaps I have a few comments from the user-only perpective: > - What is your evaluation of the design? I think the design is appropiate in terms of purely extending lexical_cast in terms of fallback values and optional exceptions. However, I was expecting more from a library that extends on lexical_cast, for example in terms of one of the goals of the library, which is compact syntax. The feature I was expecting was conversion based on default casting. In the library it seems that the source type can be omitted (just as in lexical_cast). I would be a desired feature that also destination types could be omitted. This could be possible using cast operator such that Destination d = auto_convert::from(s); // or convert<>::from(s) // default template parameter interpreted as potential auto conversion based on destination type. Instead of the redundant Destination d = convert<Destination>::from(s); I think the requested feature (unless it is not possible, in that case I am sorry about my request) is to be expected from the library. > - What is your evaluation of the implementation? I have no comments on it since I wouldn't be able to judge on implementation used. > - What is your evaluation of the documentation? The documentation is understandable and appropriate. > - What is your evaluation of the potential usefulness of the > library? I would use the library just based in considering the natural and explicit syntax introduced. Even more if the requested feature above is introduced. > - Did you try to use the library? With what compiler? Did you > have any problems? no > - How much effort did you put into your evaluation? A glance? A > quick reading? In-depth study? A glance > - Are you knowledgeable about the problem domain? no. Only from the point of view convenience. > - Do you think the library should be accepted as a Boost library? yes, I think it should be accepted. I hope this quick review is useful to make a decision. Although the validity and weight of my vote can be objected because I am not really an active player of the Boost community. Thank you, Alfredo Correa

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