Re: Bug on sizeof(void) == 1, must be undefined or negative, == -100000.

[Andrew Pinski <pinskia at physics dot uc dot edu>]

On Jun 17, 2005, at 5:27 PM, jc-nospam@jr-pizarro.jazztel.es wrote:

> On Jun 17, 2005, at 17:05:37, pinskia@physics.uc.edu wrote:
>
>
> void *z = y; // -> z = 0xBAD0DAD5
> z++;         // adding +0? adding +1? adding +4? abort this error?

Since this is a GNU extension, GCC defines as adding 1.  See the  
documentation
where this is documented.
http://gcc.gnu.org/onlinedocs/gcc-4.0.0/gcc/Pointer-Arith.html#Pointer- 
Arith


 In GNU C, addition and subtraction operations are supported on  
pointers to void and on pointers to functions. This is done by treating  
the size of a void or of a function as 1.

 A consequence of this is that sizeof is also allowed on void and on  
function types, and returns 1.

The option -Wpointer-arith requests a warning if these extensions are  
used.

-- Pinski