Manual Pages for UNIX Operating System command usage for man tirdwr

STREAMS Modules                                        tirdwr(7M)



NAME
     tirdwr - Transport Interface  read/write  interface  STREAMS
     module

SYNOPSIS
     int ioctl( fd, I_PUSH, "tirdwr");


DESCRIPTION
     tirdwr is a  STREAMS  module   that  provides  an  alternate
     interface  to a transport provider which supports the  Tran-
     sport Interface ("TI") functions  of  the  Network  Services
     library  (see Section 3N). This alternate interface allows a
     user to communicate with the  transport  protocol   provider
     using   the    read(2)   and   write(2)  system  calls.  The
     putmsg(2) and  getmsg(2) system calls may also be used. How-
     ever,  putmsg  and  getmsg  can  only transfer data messages
     between  user and stream; control portions are disallowed.


     The tirdwr  module  must  only  be  pushed  (see  I_PUSH  in
     streamio(7I)) onto a stream terminated by a transport proto-
     col provider which supports the TI. After the tirdwr  module
     has  been pushed onto a stream, none of the TI functions can
     be used. Subsequent calls to TI functions cause an error  on
     the  stream.  Once  the error is detected, subsequent system
     calls on the stream  return  an  error  with  errno  set  to
     EPROTO.


     The following are the actions taken  by  the  tirdwr  module
     when   pushed   on   the   stream,   popped  (see  I_POP  in
     streamio(7I)) off  the stream, or when data  passes  through
     it.

     push     When the module is pushed onto a stream, it  checks
              any  existing  data destined for the user to ensure
              that only regular data  messages  are  present.  It
              ignores  any  messages on the stream that relate to
              process management, such as messages that  generate
              signals  to  the user processes associated with the
              stream. If any  other  messages  are  present,  the
              I_PUSH  will  return  an  error  with  errno set to
              EPROTO.


     write    The module takes the following actions on data that
              originated from a write system call:

                  o    All messages with the  exception  of  mes-
                       sages  that  contain control portions (see
                       the putmsg and getmsg  system  calls)  are



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STREAMS Modules                                        tirdwr(7M)



                       transparently  passed  onto  the  module's
                       downstream neighbor.

                  o    Any zero length data messages are freed by
                       the  module  and  they  will not be passed
                       onto the module's downstream neighbor.

                  o    Any messages with  control  portions  gen-
                       erate  an  error,  and  any further system
                       calls associated  with  the  stream  fails
                       with errno set to EPROTO.


     read     The module takes the following actions on data that
              originated from the transport protocol provider.

              All messages with the exception of those that  con-
              tain  control  portions  (see the putmsg and getmsg
              system calls) are  transparently  passed  onto  the
              module's  upstream  neighbor.  The  action taken on
              messages with control portions will be as follows:

                  o    Any data messages  with  control  portions
                       have the control portions removed from the
                       message before to passing the  message  on
                       to the upstream neighbor.

                  o    Messages that represent an orderly release
                       indication  from  the  transport  provider
                       generate a zero length data message, indi-
                       cating the end of file, which will be sent
                       to the reader of the stream.  The  orderly
                       release  message  itself  is  freed by the
                       module.

                  o    Messages  that   represent   an   abortive
                       disconnect  indication  from the transport
                       provider  cause  all  further  write   and
                       putmsg system calls to fail with errno set
                       to ENXIO. All further read and getmsg sys-
                       tem  calls  return zero length data (indi-
                       cating end of file) once all previous data
                       has been read.

                  o    With the exception of the above rules, all
                       other  messages with control portions gen-
                       erate an  error  and  all  further  system
                       calls associated with the stream will fail
                       with errno set to EPROTO.
              Any zero length data  messages  are  freed  by  the
              module  and  they  are not passed onto the module's
              upstream neighbor.



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STREAMS Modules                                        tirdwr(7M)



     pop      When the module is popped off  the  stream  or  the
              stream  is  closed,  the module takes the following
              action:

                  o    If an orderly release indication has  been
                       previously   received,   then  an  orderly
                       release request will be sent to the remote
                       side of the transport connection.


SEE ALSO
     Intro(3), getmsg(2), putmsg(2), read(2), write(2), Intro(3),
     streamio(7I), timod(7M)


     STREAMS Programming Guide







































SunOS 5.11           Last change: 3 Jul 1990                    3