READNUM(9) READNUM(9)
NAME
readnum, readstr - return values from read from device
SYNOPSIS
int readstr(ulong off, char *buf, ulong n, char *str)
int readnum(ulong off, char *buf, ulong n, ulong val, int
size)
DESCRIPTION
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.
SOURCE
/sys/src/9/port/devcons.c
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