/* Returns: the time difference in number of milliseconds.  */
long tvdiff(struct timeval newer, struct timeval older)
/* Returns: the time difference in number of milliseconds.  */
long tvdiff(struct timeval newer, struct timeval older)
{
  return (long)(newer.tv_sec-older.tv_sec)*1000+
    (long)(newer.tv_usec-older.tv_usec)/1000;
}