"Michael Gong" <[EMAIL PROTECTED]> writes:
> One explanation could be:
>
> ----- Original Message -----
> From: "Jan Beulich" <[EMAIL PROTECTED]>
> To: <gcc@gcc.gnu.org>
> Sent: Monday, September 25, 2006 11:23 AM
> Subject: preprocessing question
>
>
>> Can anyone set me strait on why, in the following code fragment
>>
>> int x(unsigned);
>>
>> struct alt_x {
>> unsigned val;
>> };
>>
>> #define x alt_x
>> #define alt_x(p) x(p+1)
>
> since "x" is already defined as a object-like macro, "x" is replaced by
> "alt_x", so this essentially is: #define alt_x(p) alt_x(p+1)
>
> Since C99 (6.10.3.9) describes:
> ... defines an object-like macro that causes each subsequent instance of
> the macro name to be replaced by the replacement list of preprocessing
> tokens that constitute the remainder of the directive.
Macro expansion does not operate on preprocessing directives unless noted
otherwise.
Andreas.
--
Andreas Schwab, SuSE Labs, [EMAIL PROTECTED]
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
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"And now for something completely different."
