Re: [PATCH] Fix "identifier redeclared" compilation error with SUN cc.

On 2007.11.15 20:58:55 -0800, Junio C Hamano wrote:

How about doing it this way?

  # ifndef FLEX_ARRAY
  #   if defined(__GNUC__)
  #     if (__GNUC__ < 3)
  #       define FLEX_ARRAY 0
  #     else
  #       define FLEX_ARRAY /* empty */
  #     endif
  #   else
        /* more cases we know we can use 0 or empty can come here */
  #   endif
  # endif

  /* if still undefined, default to the safe, old fashioned way */
  # ifndef FLEX_ARRAY
  #   define FLEX_ARRAY 1
  # endif

Yeah, looks a bit smarter.

The basic idea is:

 * The user (from Makefile command line, config.mak, or you
   could add autoconf test) can pass -DFLEX_ARRAY=... to specify
   exactly what should happen;

Eeeek! He said autoconf! Waaah! ... Ehrm, sorry where was I?

 * Otherwise, if we happen to know for sure that we can use "0"
   or "/* empty */" with the compiler, we define FLEX_ARRAY;
   currently we know such things for gcc.

 * For everybody else, we use safer default of "1".  IOW, if you
   know your compiler does not grok "/* empty */" nor "0", you
   do not have to do anything special but use the default case
   as everybody else.

Yep, definitely better than my patch.

Björn