--- pos=(pos)
--- seek(pos)

    ǥ쥯ȥꥹȥ꡼ɤ߹֤߰ pos ˰ưޤ
    posDir#tell [Dir/tell] Ϳ줿ͤǤʤФʤ
    

    pos= ϱդ֤ޤseek  self ֤ޤ

