Re: offset of structure fields

[Massimiliano Cialdi <cialdi at firenze dot net>]

On Wed, 07 Jul 2004 07:58:14 -0500
Eljay Love-Jensen <eljay@adobe.com> wrote:

> Try this...
> 
> -----------------------------------------------
> #include <stddef.h> /* stddef.h has offsetof macro. */
> 
> typedef unsigned short int u16_t;
> typedef unsigned char u8_t;
> 
> typedef struct
> 
>      struct {
>          u16_t ff1;
>          u16_t ff2;
>          u16_t ff3;
>      } f1[3];
>      u8_t f2;
>      u8_t f3;
>      u8_t f4;
>      u16_t f5;
> } Param_t;
> 
> int main()
> 
>      size_t dist;
> 
>      dist = offsetof(Param_t, f1[0].ff1);
>      printf("f1[0].ff1 is at byte %lu\n", (unsigned long int)dist);
> 
>      dist = offsetof(Param_t, f1[2].ff2);
>      printf("f1[2].ff2 is at byte %lu\n", (unsigned long int)dist);
> 
>      dist = offsetof(Param_t, f3);
>      printf("f3        is at byte %lu\n", (unsigned long int)dist);
> 
> 
> /* Output, using GCC 3.3.1 on Cygwin / WinNT
> f1[0].ff1 is at byte 0
> f1[2].ff2 is at byte 14
> f3        is at byte 19
> */
I'm using gcc 3.3.2 cross compiler for renesas h8s micros, and it
doesn't work.
Inthe official gcc docs it seems that offsetof (and
__builtin_offsetof) is supported in version 3.5.0.

thanks


-- 
Massimiliano Cialdi
cialdi@firenze.net
m.cialdi@oksys.it