pckt(7M)

NAME

     pckt - STREAMS Packet Mode module

SYNOPSIS

     int ioctl( fd, I_PUSH, "pckt");

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  I_PUSH on   streamio(7I))  onto  the  master
     side of a pseudo terminal.

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

     On the  read-side,  only  the  M_PROTO,  M_PCPROTO,  M_STOP,
     M_START, M_STOPI, M_STARTI,
      M_IOCTL, M_DATA, M_FLUSH, and  M_READ messages are  packet-
     ized.  All  other  message types are passed upstream unmodi-
     fied.

     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() function. The control part of the message  con-
     tains  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),  ioctl(2),  ldterm(7M),  ptem(7M),  streamio(7I),
     termio(7I)

     STREAMS Programming Guide