      integer sf_create,sf_write,sf_read,sf_wait, sf_destroy
      integer sf_waitall, sf_open, sf_close, sf_rwtor
      integer sf_create_suffix
      external sf_create,sf_write,sf_read,sf_wait, sf_destroy
      external sf_waitall, sf_open, sf_close, sf_rwtor
      external sf_create_suffix
