Re: [newlib] print formats for FAST and LEAST types

[Corinna Vinschen <vinschen at redhat dot com>]

On Jul 14 15:34, Andre Vieira wrote:
> On 14/07/15 15:18, Corinna Vinschen wrote:
> >On Jul 14 15:08, Andre Vieira wrote:
> >>On 14/07/15 14:49, Corinna Vinschen wrote:
> >>>I just checked this on 32 bit Cygwin:
> >>>
> >>>   $ gcc -E - <<EOF
> >>>   #include <inttypes.h>
> >>>   #include <stdint.h>
> >>>   __INT_FAST32_TYPE__
> >>>   PRIdFAST32
> >>>   EOF
> >>>   [...]
> >>>   int
> >>>   "d"
> >>>
> >>>If there's still anything wrong with that, feel free to send patches.
> >>>
> >>>
> >>>Corinna
> >>>
> >>
> >>Hi Corinna,
> >>
> >>I am on a newer version than the linked patch.
> >>
> >>However when I run your example I get int and "ld".
> >>In your example, if you pass -dM, does it show INT32_EQ_LONG to be defined?
> >
> >No, it's undefined.  This is i686-pc-cygwin.  Please have a look at
> >libc/include/sys/_intsup.h  and try to find out why this doesn't work
> >for your target.
> >
> >
> >Thanks,
> >Corinna
> >
> 
> Hi Corinna,
> 
> It doesn't work because PRIdFAST32 uses __PRI32(d) as a definition and in
> the patch you mentioned earlier __PRI32(d) is defined as "ld" if
> _INT32_EQ_LONG is defined.
> 
> However __INT_FAST32_TYPE__ is a builtin defined in '<GCC
> SRC>/gcc/c-family/c-common.c' using INT_FAST32_TYPE, which is defined in
> '<GCC SRC>/gcc/config/newlib-stdint.h' as:
> #define INT_FAST32_TYPE (INT_TYPE_SIZE >= 32 ? "int" : INT_LEAST32_TYPE)
> 
> So if INT_TYPE_SIZE == LONG_TYPE_SIZE, int_fast32_t will be 'int' and
> PRIdFAST32 will yield "ld" and printf won't like that.

Your analysis is missing something.  Have another look at the check in
libc/include/sys/_intsup.h:

  [...]
  #undef signed
  #undef int
  #undef long
  #define signed +0
  #define int +0
  #define long +1
  [...]
  #if __INT32_TYPE__ == 1
  #define _INT32_EQ_LONG
  #elif __INT32_TYPE__ == 0
  /* Nothing to define because int32_t is safe to print as an int. */
  #else
  #error "Unable to determine type definition of int32_t"
  #endif
  #undef long
  #undef int
  #undef signed
  [...]

__INT32_TYPE__ is defined by GCC as well.  If __INT_FAST32_TYPE__ is
int, then why is __INT32_TYPE__ long?  And if that's the right thing to
do, we need a patch to sys/_intsup.h to apply the same check to
__INT_FAST32_TYPE__ and use that to define __PRI32fast and __SCN32fast
macros.


Corinna

-- 
Corinna Vinschen
Cygwin Maintainer
Red Hat

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