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

[Daniel Jacobowitz <drow at false dot org>]

On Wed, Sep 21, 2005 at 07:03:49PM +0530, Gaurav Gautam, Noida wrote:
> 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 ?

C99, section 6.7.2.2:

       [#3]  The  identifiers in an enumerator list are declared as
       constants that have type int and may  appear  wherever  such
       are  permitted.

...

       [#4] Each enumerated type shall be compatible with  char,  a
       signed  integer  type,  or  an  unsigned  integer type.  The
       choice  of  type  is  implementation-defined,  but  shall be
       capable of representing the values of all the members of the
       enumeration.

I'm not 100% sure what #3 means for enumerators whose value does not
fit in the range of "int", but it's pretty clear that the
implementation is not allowed to change the type of enumerators.


-- 
Daniel Jacobowitz
CodeSourcery, LLC