pckt(7)pckt(7)NAMEpckt - Packet Mode module for STREAMS pty (pseudo-terminal)
SYNOPSISDESCRIPTION
The feature for STREAMS pty devices allows the user process on the mas‐
ter side of the pty device to be informed of state changes in the pty.
To enable in the STREAMS pty device, the user process must push the
module onto the master side of the pty with a call to the STREAMS
ioctl(2) system call. When the module is pushed onto a STREAMS pty
master, certain STREAMS messages going upstream on the master side will
get packetized so they can be subsequently retrieved by the master side
with a function.
When the user process writes data, the module passes the message
unchanged downstream on to the next module or driver. When the user
process reads data or when the module receives certain STREAMS message
types, it constructs a packet out of the message for forwarding
upstream. To construct a message packet, the module creates an mes‐
sage. This message contains the original message type in the first
data block and the original message in as many data blocks as needed.
The user process can then retrieve the message with a call to the func‐
tion.
The module packetizes the following STREAMS message types:
All other messages are passed unchanged upstream.
If the message is an message, the module looks at the flag and takes
the following actions:
· If the flag is the module changes it to before creating the
message and passing the message upstream. This prevents the
stream head's read queue from being flushed by the original
· If the flag is the module changes it to before creating the
message and passing it upstream. To flush the write queues
properly, the module also sends an message with the flag set.
· If the flag is the module changes it to before creating the
message and passing it upstream. To flush the write queues
properly, the module also sends an message with the flag set.
AUTHOR
was developed by HP and OSF.
SEE ALSOgetmsg(2), ioctl(2), ptm(7), pts(7), ldterm(7), ptem(7), streamio(7).
pckt(7)