判断栈的增长

其实就是在函数中记录自动变量的地址； 递归再次调用函数重复入栈再次记录其地址， 比较两次地址， 就可以知道栈帧增长的方向，自然就知道了栈增长的方向

#include
static void find_stack_direction(void);
static int stack_dir;
int main(void)
{
  find_stack_direction();
  if(stack_dir==1)
     puts("stack grew upward");
  else
     puts("stack grew downward");
  return 0;
}
static void find_stack_direction (void)
{
  static char   *addr = NULL;   /* address of first
                                   `dummy', once known */
  auto char     dummy;          /* to get stack address */

  if (addr == NULL)
    {                           /* initial entry */
      addr = &dummy;

      find_stack_direction ();  /* recurse once */
    }
  else                          /* second entry */
    if (&dummy > addr)
      stack_dir = 1;            /* stack grew upward */
    else
      stack_dir = -1;           /* stack grew downward */
}