PCKT(4M) STREAMS Modules PCKT(4M)
NAME
pckt - STREAMS Packet Mode module
SYNOPSIS
int ioctl(
fd, I_PUSH, "pckt");
DESCRIPTION
pckt is a STREAMS module that may be used with a pseudo terminal to
packetize certain messages. The
pckt module should be pushed (see
I_PUSH on
streamio(4I)) onto the manager side of a pseudo terminal.
Packetizing is performed by prefixing a message with an
M_PROTO message.
The original message type is stored in the 1 byte data portion of the
M_PROTO message.
On the read-side, only the
M_PROTO,
M_PCPROTO,
M_STOP,
M_START,
M_STOPI,
M_STARTI,
M_IOCTL,
M_DATA,
M_FLUSH, and
M_READ messages are packetized.
All other message types are passed upstream unmodified.
Since all unread state information is held in the manager's stream head
read queue, flushing of this queue is disabled.
On the write-side, all messages are sent down unmodified.
With this module in place, all reads from the manager side of the pseudo
terminal should be performed with the
getmsg(2) or
getpmsg() function.
The control part of the message contains the message type. The data part
contains the actual data associated with that message type. The onus is
on the application to separate the data into its component parts.
SEE ALSO
getmsg(2),
ioctl(2),
streamio(4I),
termio(4I),
ldterm(4M),
ptem(4M) STREAMS Programming Guide February 5, 2022
PCKT(4M)