struct __sFILE {
  unsigned char *_p;	/* current position in (some) buffer */
  int	_r;    /* read space left for getc() */
  int	_w;    /* write space left for putc() */
  short	_flags;    /* flags, below; this FILE is free if 0 */
  short	_file;    /* fileno, if Unix descriptor, else -1 */
  struct __sbuf _bf;	/* the buffer (at least 1 byte, if !NULL) */
  int	_lbfsize;	/* 0 or -_bf._size, for inline putc */

#ifdef _REENT_SMALL
  struct _reent *_data;
#endif

  /* operations */
  void *	_cookie;	/* cookie passed to io functions */

  _READ_WRITE_RETURN_TYPE (*_read) (struct _reent *, void *,
        	   char *, _READ_WRITE_BUFSIZE_TYPE);
  _READ_WRITE_RETURN_TYPE (*_write) (struct _reent *, void *,
        	    const char *,
        	    _READ_WRITE_BUFSIZE_TYPE);
  _fpos_t (*_seek) (struct _reent *, void *, _fpos_t, int);
  int (*_close) (struct _reent *, void *);

  /* separate buffer for long sequences of ungetc() */
  struct __sbuf _ub;	/* ungetc buffer */
  unsigned char *_up;	/* saved _p when _p is doing ungetc data */
  int	_ur;    /* saved _r when _r is counting ungetc data */

  /* tricks to meet minimum requirements even when malloc() fails */
  unsigned char _ubuf[3];	/* guarantee an ungetc() buffer */
  unsigned char _nbuf[1];	/* guarantee a getc() buffer */

  /* separate buffer for fgetline() when line crosses buffer boundary */
  struct __sbuf _lb;	/* buffer for fgetline() */

  /* Unix stdio files get aligned to block boundaries on fseek() */
  int	_blksize;	/* stat.st_blksize (may be != _bf._size) */
  _off_t _offset;	/* current lseek offset */

#ifndef _REENT_SMALL
  struct _reent *_data;	/* Here for binary compatibility? Remove? */
#endif

#ifndef __SINGLE_THREAD__
  _flock_t _lock;	/* for thread-safety locking */
#endif
  _mbstate_t _mbstate;	/* for wide char stdio functions. */
  int   _flags2;        /* for future use */
};

struct __file {
	char	*buf;    /* buffer pointer */
	unsigned char unget;	/* ungetc() buffer */
	uint8_t	flags;    /* flags, see below */
#define __SRD	0x0001    /* OK to read */
#define __SWR	0x0002    /* OK to write */
#define __SSTR	0x0004    /* this is an sprintf/snprintf string */
#define __SPGM	0x0008    /* fmt string is in progmem */
#define __SERR	0x0010    /* found error */
#define __SEOF	0x0020    /* found EOF */
#define __SUNGET 0x040    /* ungetc() happened */
#define __SMALLOC 0x80    /* handle is malloc()ed */
#if 0
/* possible future extensions, will require uint16_t flags */
#define __SRW	0x0100    /* open for reading & writing */
#define __SLBF	0x0200    /* line buffered */
#define __SNBF	0x0400    /* unbuffered */
#define __SMBF	0x0800    /* buf is from malloc */
#endif
	int	size;    /* size of buffer */
	int	len;    /* characters read or written so far */
	int	(*put)(char, struct __file *);	/* function to write one char to device */
	int	(*get)(struct __file *);	/* function to read one char from device */
	void	*udata;    /* User defined and accessible data. */
};