RE: No effect of -fshort-enums..is it a bug

["Gaurav Gautam, Noida" <gauravga at noida dot hcltech dot com>]

Thanks for the reply, but I did not get the answer to my question.
My question is:
In the below mentioned program

 #include <stdio.h>
 int main()
 {
   enum aa {
   a = 0, b =127  , c
   };
printf("size = %d  %d %d\n", sizeof(enum aa),sizeof(b),sizeof(c));
printf("value= %d  %d %d\n", a,b,c);
return 0;
)
 
 The output is
 size = 1  1 1
 value= 0  127 128
 when  gcc (GCC) 3.3.1 (SuSE Linux) is used with -fshort-enums.
 
 And
 
 size = 1  4 4
 value= 0  127 128
 when (GCC) 4.1.0 20050915 (experimental) is used with -fshort-enums.
 
Please confirm which of the two outputs is correct and why is there a
difference in the output of two versions of compiler?

Thanks
Gaurav gautam


> -----Original Message-----
> From: Gaurav Gautam, Noida
> Sent: Wednesday, September 21, 2005 7:04 PM
> To: 'gcc@gcc.gnu.org'; 'gcc-help@gcc.gnu.org'
> Cc: 'Daniel Jacobowitz'
> Subject: RE: No effect of -fshort-enums..is it a bug
> 
> Thanks for the reply,
> 
> But why is there a difference in the output of same tc, with an old
gcc
> compiler and a new version of compiler.
> 
> Was there a bug in the earlier gcc.
> 
> I have a doubt.
> 
> Gcc manual says that
> 
> "-fshort-enums
>     Allocate to an enum type only as many bytes as it needs for the
> declared range of possible values. Specifically, the enum type will be
> equivalent to the smallest integer type which has enough room."
> 
> Does -fshort-enum guides the size of enumeration type or the size of
> enumerator constant ?
> 
> After modifying the tc as
> 
> #include <stdio.h>
> int main()
> {
>         enum aa {
>         a = 0, b =127  , c
>         };
> 
>         printf("size = %d  %d %d\n", sizeof(enum aa),sizeof(b),
> sizeof(c));
>         printf("value= %d  %d %d\n", a,b,c);
> 	  return 0;
> )
> 
> The output is
> 
> size = 1  1 1
> value= 0  127 128
> when  gcc (GCC) 3.3.1 (SuSE Linux) is used with -fshort-enums.
> 
> 
> And
> 
> size = 1  4 4
> value= 0  127 128
> 
> when (GCC) 4.1.0 20050915 (experimental) is used with -fshort-enums.
> 
> Which of the two output is standard confirming.?
> 
> 
> > -----Original Message-----
> > From: Daniel Jacobowitz [mailto:drow@false.org]
> > Sent: Wednesday, September 21, 2005 6:10 PM
> > To: Gaurav Gautam, Noida
> > Cc: gcc@gcc.gnu.org; gcc-help@gcc.gnu.org
> > Subject: Re: No effect of -fshort-enums..is it a bug
> >
> > On Wed, Sep 21, 2005 at 05:46:58PM +0530, Gaurav Gautam, Noida
wrote:
> > > int main()
> > > {
> > >         enum aa {
> > >         a = 0, b =127  , c
> > >         };
> > >
> > >         printf("size = %d  %d %d\n", sizeof(a),sizeof(b),
sizeof(c));
> > >         printf("value= %d  %d %d\n", a,b,c);
> > >         return 0;
> > > }
> >
> > > The option -fshort-enums has no effect and the output is same as
it is
> > without this option.
> >
> > It's not a bug.  Add sizeof(enum aa) to your printf; _that_ will be
> > affected by -fshort-enums.  The type of the enumerators remains int.
> >
> > --
> > Daniel Jacobowitz
> > CodeSourcery, LLC