READNUM(9)                                             READNUM(9)

          readnum, readstr - device read routines

          int readstr(ulong off, char *buf, ulong n, char *str)

          int readnum(ulong off, char *buf, ulong n, ulong val, int

          Readstr and readnum simplify the return of strings and num-
          bers from device read routines, because they deal with any
          buffering and boundary cases.  Several parameters to the
          read call are often handed on directly to these functions:
          the file offset, as off; the address of the user's buffer,
          as buf; and the number of bytes requested, as n. Both func-
          tions return the number of bytes they have stored in buf,
          and which can often be returned directly from the device
          read routine.

          Readstr satisfies a read by copying data into buf from the
          NUL-terminated string in str. The data transferred is
          selected and limited by off, n and the length of str.

          Readnum converts the unsigned integer val to a decimal rep-
          resentation in buf. The value is right-justified in a field
          of size-1 places and is followed by a blank.  Size can be
          the global constant `NUMSIZE' for 32-bit integers; the larg-
          est size allowed is 64 bytes.


     Page 1                       Plan 9             (printed 5/24/24)