C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  DistanceInStruct macro.          C++Talk.NET Forum Index -> C++ language (comp.lang.c++) View previous topic :: View next topic   Author Message lallous Guest Posted: Sun Jun 29, 2003 7:45 pm    Post subject: DistanceInStruct macro. I have the following: struct struc1 { int a; int b; int c; }; #define DistanceInStruct(member, struc) (unsigned long)((unsigned long)(&struc.member) - (unsigned long)(&struc)) I can to this: int main() { struc1 A; int pos = DistanceInStruct(b, A); // returns 1 * sizeof(int) pos = DistanceInStruct(c, A); // returns 2 * sizeof(int) } how can i accomplish the same but w/o having to declare a local variable "A" of type 'struc1' ? Regards, Elias Back to top John Harrison Guest Posted: Sun Jun 29, 2003 7:55 pm    Post subject: Re: DistanceInStruct macro. "lallous" <lallous (AT) lgwm (DOT) org> wrote Quote: I have the following: struct struc1 { int a; int b; int c; }; #define DistanceInStruct(member, struc) (unsigned long)((unsigned long)(&struc.member) - (unsigned long)(&struc)) I can to this: int main() { struc1 A; int pos = DistanceInStruct(b, A); // returns 1 * sizeof(int) pos = DistanceInStruct(c, A); // returns 2 * sizeof(int) } how can i accomplish the same but w/o having to declare a local variable "A" of type 'struc1' ? Regards, Elias Use the offsetof macro, defined in <stddef.h> int pos = offsetof(struc1, b); john Back to top lallous Guest Posted: Mon Jun 30, 2003 10:22 am    Post subject: Re: DistanceInStruct macro. Hi John, Thanks that what I was looking for. Elias 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.