plan9 man page for read

READ(2) 							System Calls Manual							   READ(2)

NAME
       read, readn, write - read or write file

SYNOPSIS
       #include <u.h>
       #include <libc.h>

       long read(int fd, void *buf, long nbytes)

       long readn(int fd, void *buf, long nbytes)

       long write(int fd, void *buf, long nbytes)

DESCRIPTION
       Read reads nbytes bytes of data from the offset in the file associated with fd into memory at buf.  The offset is advanced by the number of
       bytes read.  It is not guaranteed that all nbytes bytes will be read; for example if the file refers to the console, at most one line  will
       be returned.  In any event the number of characters read is returned.  A return value of 0 is conventionally interpreted as end of file.

       Readn is just like read, but does successive read calls until nbytes have been read, or a read system call returns a non-positive count.

       Write  writes nbytes bytes of data starting at buf to the file associated with fd at the file offset.  The offset is advanced by the number
       of bytes written.  The number of characters actually written is returned.  It should be regarded as an error if this is	not  the  same	as
       requested.

SOURCE
       /sys/src/libc/9syscall
       /sys/src/libc/port/readn.c

SEE ALSO
       intro(2), open(2), dup(2), pipe(2)

DIAGNOSTICS
       These functions set errstr.

																	   READ(2)