#include <stdio.h>
 
void foo( unsigned char a, 
	  unsigned char b, 
	  unsigned char c, 
	  ...  )
{
	unsigned char *d1 = &c - 1;
	unsigned char *d2 = &c - 1;

        printf( "a: %p\nb: %p\nc: %p\n", 
                (void *)&a, 
                (void *)&b, 
                (void *)&c );
        printf( "d1: %hhu\n", 
		*d1 );
        printf( "d2: %hhu\n", 
		*d2 );
}
 
 
 
int main(void)
{
        foo( 1, 2, 3, 4 );
 
 
        return 0;
}