$home/manuals/unix_v8/4/connld

CONNLD(4)                  Kernel Interfaces Manual                  CONNLD(4)



NAME
       connld - unique stream connection

DESCRIPTION
       This  stream  module  (see stream(4)) is used to provide unique connec‐
       tions to a server.  The file descriptor fd should refer to an end of  a
       stream-usually  a pipe-that will subsequently be mounted onto a file by
       gmount(2).  When an open or creat(2) call is applied to a  stream-asso‐
       ciated  file  with  this module installed, a new pipe is created inter‐
       nally.  A message identical to that described for the FIOSNDFD  request
       (see  stream(4))  is  sent along the stream to the process at the other
       end.  This process must respond in one of these  ways:  it  may  simply
       write some data, or reply with

            ioctl(fd1, FIOACCEPT, (char *)NULL);

       Then the attempt to open the stream succeeds, and the returned file de‐
       scriptor refers to the new pipe, whose other end is held by the  server
       process.  It may also respond by passing a new file descriptor, using

            ioctl(fd1, FIOSNDFD, &fd2);

       Then the local end of the internally-created pipe is discarded, and the
       returned file descriptor refers to the transmitted file.

       On the other hand, if the server process closes  the  transmitted  file
       descriptor, or does

            ioctl(fd1, FIOREJECT, (char *)NULL);

       then the attempt to open fails.

       Finally,  if  the  entity, whether process or device, that receives the
       FIOSNDFD message fails to respond in some appropriate way, the  process
       attempting to open the file will wait until it is sent a signal, or the
       system is rebooted, or the end of eternity, whichever comes first.



                                                                     CONNLD(4)