C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  aCC vs g++          C++Talk.NET Forum Index -> C++ language (comp.lang.c++) View previous topic :: View next topic   Author Message Michael Krause Guest Posted: Thu Feb 26, 2004 9:43 am    Post subject: aCC vs g++ Hello group, I was wondering, is there anything in this short snippet of code that violates some C++ standard? -- cut here -- static void f (double *z) { } template <class T> static void g (T *y) { f(y); } int main (int argc, char **argv) { double x = 0.0; g(&x); return 0; } -- cut here -- Reason I am asking is, g++ 3.3.2 compiles fine, whereas HP's aCC B3910B A.03.37 and B3910B A.03.31 produce this error message: Error 328: "msng.c", line 11 # Function 'f' has not been defined yet; cannot call. f(y); ^ Error 556: "msng.c", line 19 # Unable to generate specialization "void g<double>(double *)" due to errors during generation. g(&x); ^^^^^ Error 556: "msng.c", line 19 # Unable to generate specialization "void g<double>(double *)" due to errors during generation. g(&x); ^^^^^ I am a bit reluctant to say this is a compiler bug, because I've been using templates for only two days, so maybe I'm just being stupid :-) Any help on this would be very much appreciated! bye, -- /* michael */ Back to top John Carson Guest Posted: Thu Feb 26, 2004 12:11 pm    Post subject: Re: aCC vs g++ "Michael Krause" <m.krause (AT) tu-harburg (DOT) de> wrote Quote: Hello group, I was wondering, is there anything in this short snippet of code that violates some C++ standard? -- cut here -- static void f (double *z) { } template <class T static void g (T *y) { f(y); } int main (int argc, char **argv) { double x = 0.0; g(&x); return 0; } -- cut here -- Reason I am asking is, g++ 3.3.2 compiles fine, whereas HP's aCC B3910B A.03.37 and B3910B A.03.31 produce this error message: Error 328: "msng.c", line 11 # Function 'f' has not been defined yet; cannot call. f(y); ^ Error 556: "msng.c", line 19 # Unable to generate specialization "void g g(&x); ^^^^^ Error 556: "msng.c", line 19 # Unable to generate specialization "void g<double>(double *)" due to errors during generation. g(&x); ^^^^^ I am a bit reluctant to say this is a compiler bug, because I've been using templates for only two days, so maybe I'm just being stupid :-) Any help on this would be very much appreciated! bye, VC++ 7.1 accepts it but Comeau rejects it. I don't know why, but if you remove the static keyword from the definition of f, then Comeau accepts it (along with VC++ 7.1). -- John Carson 1. To reply to email address, remove donald 2. Don't reply to email address (post here instead) Back to top tom_usenet Guest Posted: Thu Feb 26, 2004 12:49 pm    Post subject: Re: aCC vs g++ On Thu, 26 Feb 2004 10:43:34 +0100, Michael Krause <m.krause (AT) tu-harburg (DOT) de> wrote: Quote: Hello group, I was wondering, is there anything in this short snippet of code that violates some C++ standard? -- cut here -- static void f (double *z) { } template <class T static void g (T *y) { f(y); The f called above is a dependent name, since its meaning depends on T. This means it is looked up at the point of instantiation. Quote: } int main (int argc, char **argv) { double x = 0.0; g(&x); return 0; } Point of instantation of g main, where g<double> is used). f is looked up here, but only external declarations are checked, so your static f isn't found. See 14.6.4.2 of the standard for details. Quote: I am a bit reluctant to say this is a compiler bug, because I've been using templates for only two days, so maybe I'm just being stupid This highlights why "static" in the context you have used it above is deprecated in the C++ standard. Use anonymous namespaces instead: namespace { void f(double *z) { } template <class T> void g(T *y) { f(y); } } int main(int argc, char **argv) { double x = 0.0; g(&x); return 0; } Tom -- C++ FAQ: http://www.parashift.com/c++-faq-lite/ C FAQ: http://www.eskimo.com/~scs/C-faq/top.html Back to top Michael Krause Guest Posted: Thu Feb 26, 2004 1:28 pm    Post subject: Re: aCC vs g++ On Thu, 26 Feb 2004, tom_usenet wrote: Quote: static void f (double *z) { } template <class T static void g (T *y) { f(y); The f called above is a dependent name, since its meaning depends on T. This means it is looked up at the point of instantiation. } int main (int argc, char **argv) { double x = 0.0; g(&x); return 0; } Point of instantation of g main, where g<double> is used). f is looked up here, but only external declarations are checked, so your static f isn't found. See 14.6.4.2 of the standard for details. I am a bit reluctant to say this is a compiler bug, because I've been using templates for only two days, so maybe I'm just being stupid :-) This highlights why "static" in the context you have used it above is deprecated in the C++ standard. Use anonymous namespaces instead: [...] Wow, it works. Just leaving out the 'static' in the definition of f fixes my problem, too. Seems like I was thinking too much "C" here, please excuse :) I suppose there is a good reason why only external declarations for f are checked during instantiation of g<double>? Thanks again, -- /* michael */ Back to top tom_usenet Guest Posted: Thu Feb 26, 2004 3:05 pm    Post subject: Re: aCC vs g++ On Thu, 26 Feb 2004 14:28:16 +0100, Michael Krause <m.krause (AT) tu-harburg (DOT) de> wrote: Quote: Wow, it works. Just leaving out the 'static' in the definition of f fixes my problem, too. Seems like I was thinking too much "C" here, please excuse :) I suppose there is a good reason why only external declarations for f are checked during instantiation of g<double>? I suspect it has something to do with avoiding violations of the ODR in template instantiations, export, etc. Implicit template instantiations from different translation units have to be merged (or only one generated in the first place), and names with internal linkage might cause some problems with this. Certainly the rule could have been avoided, but deprecating static works just as well, since there's no good reason to use it in C++. Tom -- C++ FAQ: http://www.parashift.com/c++-faq-lite/ C FAQ: http://www.eskimo.com/~scs/C-faq/top.html 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 (comp.lang.c++) 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.