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Re: Strange behaviour gcc 3.0


Igmar Palsenberg <i.palsenberg@jdimedia.nl> writes:

> On 1 Aug 2001, Alexandre Oliva wrote:
> 
>> On Aug  1, 2001, Igmar Palsenberg <i.palsenberg@jdimedia.nl> wrote:
>>
>> >         printf("bogus"
>> > #ifdef TEST
>> >         "testing"
>> > #endif
>> >         );
>>
>> > [root@wrkst SPECS]# gcc -O2 -o x x.c
>> > x.c:7:1: directives may not be used inside a macro argument
>> > x.c:7:1: unterminated argument list invoking macro "printf"
>> > x.c: In function `main':
>> > x.c:10: parse error before ')' token
>>
>> > Code didn't change. This really strikes me.. Anyone can comment on this ??
>>
>> printf is a macro (don't ask me why; it's a glibc implementation
>> detail that is authorized by the C Standard), and there can't be
>> preprocessor directives inside a macro argument list.
> 
> It's indeed in bits/stdio.h.
> 
> Is there a define available to see if I'm using gcc 3.0 ?? Older versions
> have no problem with above code, and the #ifdef in printf() is massively
> used in the programs I'm recompiling.

ISO C99 allows you to #undef printf, just do after inclusion of
stdio.h

But note that ISO C allows every function to be a macro,

Andreas
-- 
 Andreas Jaeger
  SuSE Labs aj@suse.de
   private aj@arthur.inka.de
    http://www.suse.de/~aj


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