Re: type-punning?

j.j.fishbat@[EMAIL PROTECTED]
 wrote:
> are you saying that
> 
> ---
> int foo(void* bar)
> {
>   char *st = (char*)bar;
>      :
> }
> 
>  :
>  :
> 
> char *bar;
>  :
> 
> foo((void*)bar);
> ---
> 
> is not possible in C?

This is not even remotely the same thing as your original code. This 
version uses _conversion_. Your original version performed memory 
reinterpretation.

Compare the following two examples:

Let's assume that sizeof(float) is the same as sizeof(int)

   float f = 1.0;
   int i;

Example 1. Conversion

   i = (int) f;
   /* Here we can expect i to be equal to 1 */
   assert(i == 1);

Example 2. Memory reinterpretation

   i = *(int*) &f;
   /* Can we say anything about the value of i here? NO! */

The difference between these tow examples is exactly the difference 
between your two code samples.

> Is there really no way at all to modify a generic
> pointer by passing a reference to it to a function?

No.

-- 
Best regards,
Andrey Tarasevich