V7/usr/man/man2/pkon.2

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.TH PKON 2
.SH NAME
pkon, pkoff \- establish packet protocol
.SH SYNOPSIS
.B pkon(fd, size)
.PP
.B pkoff(fd)
.SH DESCRIPTION
.I Pkon
establishes packet protocol (see
.IR pk (4))
on the open character special file whose file
descriptor is
.I fd.
.I Size
is a desired packet size, a power of 2 in the range
.RI 32\(<= size \(<=4096.
The size is negotiated with a remote packet driver,
and a possibly smaller actual packet size is returned.
.PP
An asynchronous line used for packet
communication should be in raw mode;
see
.IR tty (4).
.PP
.I Pkoff
turns off the packet driver on the channel whose
file descriptor is
.I fd.
.SH SEE ALSO
pk(4), pkopen(3), tty(4), signal(2)
.SH DIAGNOSTICS
.I Pkon
returns \-1 if 
.I fd
does not describe an open file, or if
packet communication cannot
be established.
.PP
.I Pkoff
returns \-1 for an unknown file descriptor.
.PP
Writing on a packet driver link that has been shut down
by
.I close
or
.I pkoff
at the other end raises signal SIGPIPE
in the writing process.