#define BUFSIZ  256
#define _NFILE  16
typedef struct _iobuf {
       char *_ptr,     /* buffer pointer */
            *_base,  /* buffer base address */
            *_end;  /* buffer end address */
       int _flag;      /* file status */
       int _fd;        /* file path number */
       char _save;     /* for 'ungetc' when unbuffered */
       int _bufsiz;    /* size of data buffer */
} FILE;

extern FILE _iob[_NFILE];

#define _READ       1
#define _WRITE      2
#define _UNBUF      4
#define _BIGBUF     8
#define _EOF        0x10
#define _ERR        0x20
#define _SCF        0x40
#define _RBF        0x80
#define _DEVMASK    0xc0
#define _WRITTEN    0x0100    /* buffer written in update mode */
#define _INIT       0x8000    /* _iob initialized */

#define EOF (-1)
#define EOL 13
#define NULL 0

#define stdin _iob
#define stdout (&_iob[1])
#define stderr (&_iob[2])

#define PMODE  0xb   /* r/w for owner, r for others */

#define fgetc      getc
#define putchar(c) putc(c,stdout)
#define getchar()  getc(stdin)
#define ferror(p)  ((p)->_flag&_ERR)
#define feof(p)    ((p)->_flag&_EOF)
#define clearerr(p) ((p)->_flag&=~_ERR)
#define fileno(p)   ((p)->_fd)

long ftell();