Technical data

SunOS 5.5 STREAMS Modules pckt(7M)
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(7I)) onto the
master side of a pseudo terminal.
Packetizing is performed by prefixing a message with an M_PROTO message. The origi-
nal 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 master’s stream head read queue, flush-
ing of this queue is disabled.
On the write-side, all messages are sent down unmodified.
With this module in place, all reads from the master 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), ldterm(7M), ptem(7M), streamio(7I), termio(7I)
STREAMS Programming Guide
modified 3 Jul 1990 7M-245