pckt - STREAMS Packet Mode module
int ioctl( fd,
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
) onto the manager side of a pseudo terminal.
Packetizing is performed by prefixing a message with an M_PROTO
The original message type is stored in the 1 byte data portion of the M_PROTO
On the read-side, only the M_PROTO
, 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)
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)
, ptem(4M) STREAMS Programming Guide
February 5, 2022 PCKT(4M)