pckt(7)                DEVICES AND MODULES                pckt(7)



NAME
     pckt - STREAMS Packet Mode module

DESCRIPTION
     pckt is a STREAMS module that may be used with a pseudo ter-
     minal to packetize certain messages.  The pckt module should
     be pushed [see IPUSH, streamio(7)] onto the master side  of
     a pseudo terminal.

     Packetizing is performed by  prefixing  a  message  with  an
     MPROTO message.  The original message type is stored in the
     4 byte data portion of the MPROTO message.

     On the  read-side,  only  the  MPROTO,  MPCPROTO,  MSTOP,
     MSTART,  MSTOPI,  MSTARTI,  MIOCTL, MDATA, MFLUSH, and
     MREAD 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, 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 master side of
     the  pseudo  terminal should be performed with the getmsg(2)
     or getpmsg() system call.  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
     crash(1M), getmsg(2), ioctl(2),
     ldterm(7), ptem(7), streamio(7), termio(7).
     Programmer's Guide: STREAMS.




















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