1 PCKT(7M)                        STREAMS Modules                       PCKT(7M)
   2 
   3 NAME
   4        pckt - STREAMS Packet Mode module
   5 
   6 SYNOPSIS
   7        int ioctl( fd, I_PUSH, "pckt");
   8 
   9 
  10 DESCRIPTION
  11        pckt is a STREAMS module that may be used with a pseudo terminal to
  12        packetize certain messages. The pckt module should be pushed (see
  13        I_PUSH on streamio(7I)) onto the manager side of a pseudo terminal.
  14 
  15 
  16        Packetizing is performed by prefixing a message with an  M_PROTO
  17        message.  The original message type is stored in the 1 byte data
  18        portion of the M_PROTO message.
  19 
  20 
  21        On the read-side, only the M_PROTO, M_PCPROTO, M_STOP, M_START,
  22        M_STOPI, M_STARTI, M_IOCTL, M_DATA, M_FLUSH, and  M_READ messages are
  23        packetized. All other message types are passed upstream unmodified.
  24 
  25 
  26        Since all unread state information is held in the manager's stream head
  27        read queue, flushing of this queue is disabled.
  28 
  29 
  30        On the write-side, all messages are sent down unmodified.
  31 
  32 
  33        With this module in place, all reads from the manager side of the
  34        pseudo terminal should be performed with the  getmsg(2) or getpmsg()
  35        function. The control part of the message contains the message type.
  36        The data part contains the actual data associated with that message
  37        type. The onus is on the application to separate the data into its
  38        component parts.
  39 
  40 SEE ALSO
  41        getmsg(2), ioctl(2), ldterm(7M), ptem(7M), streamio(7I), termio(7I)
  42 
  43 
  44        STREAMS Programming Guide
  45 
  46                                February 5, 2022                       PCKT(7M)