(PHP 4, PHP 5, PHP 7)
imap_close — Close an IMAP stream
$imap_stream
   [, int $flag = 0
  ] )Closes the imap stream.
imap_stream由 imap_open() 返回的 IMAP 流。
flag
       If set to CL_EXPUNGE, the function will silently
       expunge the mailbox before closing, removing all messages marked for
       deletion. You can achieve the same thing by using
       imap_expunge()
      
   成功时返回 TRUE, 或者在失败时返回 FALSE。