line discipline for unique stream connections
connld is a STREAMS-based module
that provides unique connections
between server and client processes.
It can only be pushed (see
onto one end of a STREAMS-based
pipe that may subsequently be attached to a name in the file system name space.
After the pipe end is attached, a new pipe is created internally when an
originating process attempts to
the file system
A file descriptor for one end of the new pipe is packaged into
a message identical to that for the ioctl I_SENDFD (see
and is transmitted along the stream to the server process on the
The originating process is blocked until the server responds.
The server responds to the I_SENDFD request
by accepting the file descriptor
through the I_RECVFD ioctl message.
When this happens, the file descriptor associated with
the other end of the new pipe
is transmitted to the originating process
as the file descriptor returned from the
If the server does not respond to the I_SENDFD request,
the stream that the connld module is pushed on
becomes uni-directional because the server
will not be able to retrieve any data off the stream
until the I_RECVFD request is issued.
If the server process exits
before issuing the I_RECVFD request, the
system calls will fail and return -1
to the originating process.
When the connld module is pushed onto a pipe, messages going back and forth
through the pipe are ignored by connld.
On success, an open of connld returns 0.
On failure, errno is set to the following values:
A stream onto which connld is being pushed is not a pipe or the pipe
does not have a write queue pointer pointing to a stream head read queue.
The other end of the pipe onto which connld is being pushed is linked
under a multiplexor.
connld is being pushed onto a pipe end whose other end is no longer
An internal pipe could not be created.
An M_HANGUP message is at the stream head of the pipe onto which
connld is being pushed.
Internal data structures could not be allocated.
A file table entry could not be allocated.
© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 25 April 2004