C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  The string returned by typeid(X).name()          C++Talk.NET Forum Index -> C++ Language (Moderated) View previous topic :: View next topic   Author Message thiago.adams@gmail.com Guest Posted: Wed Aug 03, 2005 3:28 pm    Post subject: The string returned by typeid(X).name() Hello, The string returned by typeid(X).name() must be equal for any compiler? If I use this string for class serialization in text mode I can use the serialization code in another compiler? thanks [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Matti Rintala Guest Posted: Wed Aug 03, 2005 6:32 pm    Post subject: Re: The string returned by typeid(X).name() [email]thiago.adams (AT) gmail (DOT) com[/email] wrote: Quote: The string returned by typeid(X).name() must be equal for any compiler? There are no special requirements whatsoever for the string returned by name(). The standard says: 18.5.1 (7): "const char* name() const; Returns: an implementation-defined NTBS. Notes: The message may be a null-terminated multibyte string (17.3.2.1.3.2), suitable for conversion and display as a wstring (21.2, 22.2.1.5)." It also says: 18.5.1 (1): "The names, encoding rule, and collating sequence for types are all unspecified and may differ between programs." So you really cannot rely on the string remaining the same even when using the same compiler. -- ------------- Matti Rintala ------------ [email]matti.rintala (AT) tut (DOT) fi[/email] ------------ Painting is the art of inclusion. Photography is an art of exclusion. [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top tony_in_da_uk@yahoo.co.uk Guest Posted: Wed Aug 03, 2005 6:33 pm    Post subject: Re: The string returned by typeid(X).name() No - it can and does differ between compilers. Cheers, Tony [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Victor Bazarov Guest Posted: Wed Aug 03, 2005 6:34 pm    Post subject: Re: The string returned by typeid(X).name() [email]thiago.adams (AT) gmail (DOT) com[/email] wrote: Quote: The string returned by typeid(X).name() must be equal for any compiler? Nope. Quote: If I use this string for class serialization in text mode I can use the serialization code in another compiler? Nope. Not even with a different version of the same compiler. There is no requirement in the Standard as to what that string should look like or whether it should look meaningful at all. V [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Gianluca Silvestri Guest Posted: Wed Aug 03, 2005 6:34 pm    Post subject: Re: The string returned by typeid(X).name() <thiago.adams (AT) gmail (DOT) com> ha scritto nel messaggio news:1123079214.990201.190290 (AT) o13g2000cwo (DOT) googlegroups.com... Quote: Hello, The string returned by typeid(X).name() must be equal for any compiler? If I use this string for class serialization in text mode I can use the serialization code in another compiler? thanks No the string returned by type_info::name is implementation defined --- Gianluca Silvestri [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Tom Widmer Guest Posted: Wed Aug 03, 2005 6:40 pm    Post subject: Re: The string returned by typeid(X).name() [email]thiago.adams (AT) gmail (DOT) com[/email] wrote: Quote: Hello, The string returned by typeid(X).name() must be equal for any compiler? If I use this string for class serialization in text mode I can use the serialization code in another compiler? No, the string is implementation defined. The usual way around this is to define some kind of ID for each polymorphic type you want to serialize. See the boost serialization library (at www.boost.org) for an example. Tom [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top richard@ex-parrot.com Guest Posted: Wed Aug 03, 2005 6:41 pm    Post subject: Re: The string returned by typeid(X).name() [email]thiago.adams (AT) gmail (DOT) com[/email] wrote: Quote: Hello, The string returned by typeid(X).name() must be equal for any compiler? No, and it typically is not. It needn't even be equal between recompilations using the same compiler. (This sometimes happens in practice for types in anonymous namespaces.) Quote: If I use this string for class serialization in text mode I can use the serialization code in another compiler? Definitely not. -- Richard Smith [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top thiago.adams@gmail.com Guest Posted: Thu Aug 04, 2005 10:33 am    Post subject: Re: The string returned by typeid(X).name() Thank's for all, I think that is interesting make a table for result of typedid().name() for diferent classes in diferent compilers. Mybe a function that normalize the names is usefull. I already see the boost serialization library, is very interesting. [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top kanze@gabi-soft.fr Guest Posted: Fri Aug 05, 2005 3:05 pm    Post subject: Re: The string returned by typeid(X).name() [email]thiago.adams (AT) gmail (DOT) com[/email] wrote: Quote: I think that is interesting make a table for result of typedid().name() for diferent classes in diferent compilers. There was a proposal to standardize the naming. It was voted down, I think because some compilers had implemented something else, and didn't want to change. Quote: Mybe a function that normalize the names is usefull. Note that the current standard doesn't even require the names to be unique within a single compiler. An implementation which always returned "" would be fully conforming. In fact, I would not be surprised if some compilers didn't occasionally use the same name for two different classes. (Sun CC does, for example.) -- James Kanze GABI Software Conseils en informatique orientée objet/ Beratung in objektorientierter Datenverarbeitung 9 place Sémard, 78210 St.-Cyr-l'École, France, +33 (0)1 30 23 00 34 [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top jeff.koftinoff@gmail.com Guest Posted: Mon Aug 08, 2005 7:52 am    Post subject: Re: The string returned by typeid(X).name() [email]kanze (AT) gabi-soft (DOT) fr[/email] wrote: Quote: snip Note that the current standard doesn't even require the names to be unique within a single compiler. An implementation which always returned "" would be fully conforming. In fact, I would not be surprised if some compilers didn't occasionally use the same name for two different classes. (Sun CC does, for example.) What is the use of having a feature defined in the standard that is fundamentally useless? Or is there some use that I can't think of that is both standard-conforming and useful? -- jeff koftinoff <jeff.koftinoff (AT) gmail (DOT) com> www.jdkoftinoff.com [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top msalters Guest Posted: Tue Aug 09, 2005 1:46 pm    Post subject: Re: The string returned by typeid(X).name() [email]jeff.koftinoff (AT) gmail (DOT) com[/email] schreef: Quote: kanze (AT) gabi-soft (DOT) fr wrote: Note that the current standard doesn't even require the names to be unique within a single compiler. An implementation which always returned "" would be fully conforming. In fact, I would not be surprised if some compilers didn't occasionally use the same name for two different classes. (Sun CC does, for example.) What is the use of having a feature defined in the standard that is fundamentally useless? Or is there some use that I can't think of that is both standard-conforming and useful? Debugging, of course. Now, typeid(X).name may be somewhat less useful, but consider typeid(*pX).name . BTW, the standard in no way guarantees usefulness. It's legal to throw std::bad_alloc from every new expression. Does that make new useless? HTH, Michiel Salters [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         C++Talk.NET Forum Index -> C++ Language (Moderated) All times are GMT Page 1 of 1   Jump to: Select a forum C/C++----------------C LanguageC Language (Moderated)C++ Language (Moderated)C++ language (comp.lang.c++)C++ language, library and standards Non-English C/C++ Newsgroups----------------C++ (German)C++ (French)  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.