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


        printf( "d: %hhu\n", 
		*d );
}
 
 
 
int main(void)
{
        foo( 1, 2, 3, 4 );
 
 
        return 0;
}