ios *toio(sl_v v, bool open, bool rd, bool wr) sl_returns_nonnull;void free_io(sl_v self);bool isio(sl_v v) sl_purefn;sl_v io_to_str(const sl_v *ps) sl_nonnull(1);void io_init(void);extern sl_v sl_iooutsym, sl_iodeffilemodesym, sl_iodefdirmodesym;extern const sl_type *sl_iotype;