pckt(7) 						 Miscellaneous Information Manual						   pckt(7)

NAME

       pckt - Packet Mode module for STREAMS pty (pseudo-terminal)

SYNOPSIS

DESCRIPTION

       The  feature  for  STREAMS  pty devices allows the user process on the master 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 message.  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:

	      o  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

	      o  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.

	      o  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 ALSO

       getmsg(2), ioctl(2), ptm(7), pts(7), ldterm(7), ptem(7), streamio(7).

																	   pckt(7)