Re: linux/macros.h(new) and linux/list.h(mod) ...

[Arnaldo Carvalho de Melo <acme@conectiva.com.br>]

Em Fri, Jul 06, 2001 at 06:38:04PM +0100, Neil Booth escreveu:
> Alan Cox wrote:-
> 
> > #define min(a,b) __magic_minfoo(a,b, __var##__LINE__, __var2##__LINE__)
> > 
> > #define __magic_minfoo(A,B,C,D) \
> > 	{ typeof(A) C = (A)  .... }
> 
> No, that's buggy.  You need an extra level of indirection to expand
> __LINE__.  Arguments to ## are inserted in-place without expansion.

yes, so lets try with another indirection and see if I'm missing something
that you could clarify :)

[acme@brinquedo __attribute__]$ cat b.c
#define _min(a,b,line) __magic_minfoo(a,b, __var##line, __var2##line)
#define min(a,b) _min(a,b,__LINE__)

#define __magic_minfoo(A,B,C,D) \
       ({ typeof(A) C = (A); typeof(B) D = (B); C>D?D:C; })

void main(void)
{
      int __var11=5, __var211=7;

      printf("min(%d,%d) = %d (should be 11: %d)\n", __var11, __var211,
             min(__var11, __var211), __LINE__);
}
[acme@brinquedo __attribute__]$ cpp < b.c
# 1 ""
void main(void)
{
      int __var11=5, __var211=7;

      printf("min(%d,%d) = %d (should be 11: %d)\n", __var11, __var211,
             ({ typeof(   __var11   )   __var__LINE__   = (   __var11   );
typeof(    __var211   )   __var2__LINE__   = (    __var211   );
__var__LINE__  >  __var2__LINE__  ?  __var2__LINE__  :  __var__LINE__  ; })
, 12);
}
[acme@brinquedo __attribute__]$

- Arnaldo