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Re: [Boost-users] Comments / Advice on using Boost Test Library
by Sohail Somani 16 Sep '06

16 Sep '06

> -----Original Message----- > From: boost-users-bounces(a)lists.boost.org > [mailto:boost-users-bounces@lists.boost.org] On Behalf Of > Matt Schuckmann > > What I'd like to ask the Boost community about is this: how to go > > about unit testing private class methods. Hi, Rather than change the interface of my classes to use friend classes (I feel this unnecessarily clutters the interface), I do something simple and evil: #define private public #define protected public # include "MyClass.hpp" #undef private #undef protected Or something along those lines. This is permissable in unit tests, I would think. Sohail

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Re: [Boost-users] [serialization] serialization of pointers to primitive types?
by JOAQUIN LOPEZ MU?Z 16 Sep '06

16 Sep '06

Hello Robert, ----- Mensaje original ----- De: Robert Ramey <ramey(a)rrsd.com> Fecha: Sábado, Septiembre 16, 2006 8:01 am Asunto: Re: [Boost-users] [serialization] serialization of pointers to primitive types? > Serialization of pointers to primitive data types is prohibited. > I'm pretty sure this is mentioned in the documentation. ( don't > have the exact reference handy) I've persued the docs and in every place where this is referred to, the statement is that primitive types are not tracked, which is IMHO different than serialization of pointers to primitive types being forbidden. Examples: - Serializable concept: "A type T is Serializable if and only if one of the following is true: * it is a primitive type. [...] * it is a pointer to a Serializable type.[...]" from which it can be deduced that a pointer to a primitive type is serializable. - Object tracking: "Default tracking traits are: * For primitive, track_never.[...]" At the risk of repeating myself, I understand what serializing a pointer to a non-tracked type involves. This is not the same as not being able to serialize the pointer in the first place, which is what happens with primitive types, to my dismay. > - and it has been noted a couple of times. The reason is that > doing this would result in ALL usages of that type being tracked > - which is probably a heck of a lot more than the user had in mind. I'm not talking about primitive types being tracked, which I agree with you implies an unacceptable burden, but about the mere possibility of serialization of a pointer to a primitive type. Wouldn't it be an option that pointers to primitive types will be handled as non-tracked? What would be the overhead of that option? In case this is an option, please consider my vote for inclusion as a new feature in Boost 1.35. > > The way to serialize pointer to primitives > (serialization_level::prmitive) is to use BOOST_STRONG_TYPEDEF to > define a new type and specify serialization function for it. This > won't work for std::string so you'll have to make a trivial > derivation of std::string if you want to serialize a pointer to a > std::string. The problem with that is that it is an intrusive solution that complicates things when dealing with generic code. Sometimes, it can be just impossible to do that intrusive change or require the user to do it. From this restriction, for instance, we have that std::set<int*> is not serializable as is. Telling the user to change her definition to something like std::set<BOOST_STRONG_TYPEDEF(...)*> just for the sake of serializability could be unacceptable in some (many?) situations. > Robert Ramey Thank you, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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Writing a more readable code
by Alexander Shyrokov 16 Sep '06

16 Sep '06

How can make the following code inside of for_each more readable? void f(char*); typedef std::map<int,char> TMap; TMap a; std::for_each(a.begin(),a.end(),boost::bind(f,boost::bind(&TMap::value_type::second,_1))); Is it possible to convert boost::bind(&TMap::value_type::second,_1) to a function object or a typedef name? -- Regards, Alexander. http://sjcomp.com

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Re: [Boost-users] [boost::serialization] Convert enumeration tostringand back again
by Nat Goodspeed 16 Sep '06

16 Sep '06

> ________________________________________ > From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Robert Ramey > Sent: Saturday, September 16, 2006 2:27 AM > To: boost-users(a)lists.boost.org > Subject: Re: [Boost-users] [boost::serialization] Convert enumeration tostringand back again > > class param_choice { > enum > { > PARAM_CHOICE_UINT8, > PARAM_CHOICE_UINT16, > PARAM_CHOICE_UINT32, > PARAM_CHOICE_INT8, > PARAM_CHOICE_BOOL > } m_current_value; > template<class Archive> > save(Archive &ar, unsigned int version) { > std::string svalue; > switch(m_current_value){ [Nat] If I were going to do this "by hand," I'd at least want to construct a map. From that I'd populate another for the reverse lookup. But that's probably because I haven't yet read up on Boost.MultiIndex. > case PARAM_CHOICE_UINT8: > svalue = "PARAM_CHOICE_UINT8"; > ... > } > ar << BOOST_SERIALIZATION_NVP(svalue); > } > template<class Archive> > load(Archive &ar, unsigned int version){ > std::string svalue; > ar >> BOOST_SERIALIZATION_NVP(svalue); > if(svalue == std::string("PARAM_CHOICE_UINT8") > m_current_value = PARAM_CHOICE_UINT8; > else > if(... > ... > } > };

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Re: [Boost-users] Library Interface Design
by Nat Goodspeed 16 Sep '06

16 Sep '06

> -----Original Message----- > From: boost-users-bounces(a)lists.boost.org [mailto:boost-users- > bounces(a)lists.boost.org] On Behalf Of Scott Meyers > Sent: Tuesday, September 12, 2006 1:09 AM > To: boost-users(a)lists.boost.org > Subject: [Boost-users] Library Interface Design > > I've always been a big fan of the "don't let users create objects they > can't really use" philosophy. So, in general, I don't like the idea of > "empty" objects or two-phase construction. It's too easy for people to > make mistakes. [Nat] I try to design for single-phase construction myself. The aberrant use case that I've bumped into is deserialization. Intrusive serialization can preserve single-phase construction -- but what if the class designer didn't anticipate the need to serialize? I haven't yet worked with a serialization framework smart enough to consider constructor arguments. (I haven't yet worked with the Boost Serialization library, either; forgive me if this is already a solved problem.)

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Re: [Boost-users] Boost serialization : Possible to append to file?
by Robert Ramey 16 Sep '06

16 Sep '06

Daniel F. Savarese wrote: > In message <20060911172413.74527.qmail(a)web57207.mail.re3.yahoo.com>, > smith smit hson writes: >> This is regarding the boost serialization library. Is >> it possible to append to a pre-existing archive file? > > I don't think anyone's answered this yet. The answer is yes. Hmmm - that would surprise me. > > While on the topic of boost serialization, I'll add an unrelated note > that you cannot safely serialize objects from different threads when > using separate archive instances in each thread. Boost serialization > uses local static variables in places like > boost:archive::detail::oserializer::instantiate(), so even though > you're > using separate archive instances, there's only a single serializer for > a given archive type/object type pair. True - but this should be no problem since the the static object never changes. That is all the functions on this static object ar "const" so they should be re-entrant. Therefore, if you concurrently > serialize the same type of object with separate instances of the same > archive type, you can segfault. I don't see this. > The solution of course is to use > critical sections or delegate all serialization to a single thread. > But you wouldn't expect to have to do so when using separate > instances because the global behavior is not obvious to the API user. I don't think this should be necessary. If it is, then it is contraty to my intentation. Robert Ramey

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[boost::serialization] Convert enumeration to string and back again
by Graham Hudspith 16 Sep '06

16 Sep '06

Another "basic" question for the list again, apologies in advance. I have a class with a data member which is an enumeration, e.g.: typedef enum param_choice { PARAM_CHOICE_UINT8, PARAM_CHOICE_UINT16, PARAM_CHOICE_UINT32, PARAM_CHOICE_INT8, PARAM_CHOICE_BOOL } param_choice_e; I can quite happily user the Boost Serialization library to save and restore a class with a data member of this type: class Stuff { friend std::ostream& operator<<(std::ostream& os, const Stuff& stuff friend class boost::serialization::access; template<class Archive> void serialize(Archive& ar, const unsigned int file_version) { ar & BOOST_SERIALIZATION_NVP(choice); } param_choice choice; public: Stuff () {} Stuff (param_choice theChoice); }; This is using XML as the file-format. The data member appears in the file as an integer. However, what I would LIKE to do is output the value of "choice" as a string (e.g. instead of outputing <choice>2</choice>, the file contains <choice>UINT32</choice>). And do a conversion when I read it all back in again, of course. Can someone please provide some pointers to where I can find out how to do this? Or an example? Is the solution going to end up along the lines of: * Split the serialize into separate load and save routines * In the save, convert the data member into a string and output this to the archive * In the load, input from the archive into a string and then store this into the data member Best regards in anticipation, Graham.

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Boost serialization : Possible to append to file?
by smith smithson 16 Sep '06

16 Sep '06

Hello, This is regarding the boost serialization library. Is it possible to append to a pre-existing archive file? i.e. Create an archive file, serialize objects to it, close file, and then re-open file and append more serialized objects to it. Is this allowed? -Thanks! __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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unordered map base on how items are inserted.
by chun ping wang 16 Sep '06

16 Sep '06

I have a question on unordered_map. Are there are any boost library containers that acts like an associative array but also have the items base on how the order their inserted in. I.E. first item inserted is first one, second one is second. Thanks.

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program_options : Executing methods required for options_description before methods for command line options.
by Booster Booster 15 Sep '06

15 Sep '06

Hi, I have a list of options that I want to store before parsing the command line option. For example, po::options_description desc; // This has a couple of options. boost::program_options::variable_map options; po::store(po::command_line_parser(command_args).options(desc).run(), options); The problem is I want to execute the methods that correspond to 'desc' before the methods required by 'command_args' . Is there a way to populate the variable_map in a way such that I get the required sequence ? I did some reading of the docs, but couldn't find a way to do it. Any help would be appreciated. Thanks in advance, Sandy.

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