'\" te
.\" Copyright 2004 AT&T
.\" Portions Copyright (c) 2004, 2015, Oracle and/or its affiliates. All       rights reserved.
.TH connld 7M "29 Jan 2015" "SunOS 5.11" "STREAMS Modules"
.SH NAME
connld \- line discipline for unique stream connections
.SH SYNOPSIS
.LP
.nf
\fB#include <sys/stream.h>\fR
\fB#include <sys/stropt.h>\fR
.fi

.LP
.nf
\fBint ioctl(\fIfd\fR,I_PUSH,"connld");\fR
.fi

.SH DESCRIPTION
.sp
.LP
\fBconnld\fR is a STREAMS-based module that provides unique connections between server and client processes. It can only be pushed (see  \fBstreamio\fR(7I)) onto one end of a STREAMS-based pipe that may subsequently be attached to a name in the file system name space with  \fBfattach\fR(3C). After the pipe end is attached, a new pipe is created internally when an  originating process attempts to  \fBopen\fR(2) or  \fBcreat\fR(2) the file system name. A file descriptor for one end of the new pipe is packaged into a message identical to that for the ioctl  \fBI_SENDFD\fR (see  \fBstreamio\fR(7I)) and is transmitted along the stream to the server process on the  other end. The originating process is blocked until the server responds.
.sp
.LP
The server responds to the  \fBI_SENDFD\fR request by accepting the file descriptor through the  \fBI_RECVFD\fR 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 \fBopen\fR(2) or \fBcreat\fR(2). 
.sp
.LP
If the server does not respond to the  \fBI_SENDFD\fR request, the stream that the \fBconnld\fR module is pushed on becomes uni-directional because the server  will not be able to retrieve any data off the stream until the  \fBI_RECVFD\fR request is issued. If the server process exits before issuing the  \fBI_RECVFD\fR request, the \fBopen\fR(2) or the \fBcreat\fR(2) invocation will fail and return -1 to the originating process.
.sp
.LP
When the \fBconnld\fR module is pushed onto a pipe, it ignores messages going back and forth  through the pipe.
.SH ERRORS
.sp
.LP
On success, an open of \fBconnld\fR returns 0. On failure, \fBerrno\fR is set to the following values:
.sp
.ne 2
.mk
.na
\fB\fBEINVAL\fR\fR
.ad
.RS 10n
.rt  
A stream onto which \fBconnld\fR is being pushed is not a pipe or the pipe does not have a write queue pointer pointing to a stream head read queue.
.RE

.sp
.ne 2
.mk
.na
\fB\fBEINVAL\fR\fR
.ad
.RS 10n
.rt  
The other end of the pipe onto which \fBconnld\fR is being pushed is linked under a multiplexor.
.RE

.sp
.ne 2
.mk
.na
\fB\fBEPIPE\fR\fR
.ad
.RS 10n
.rt  
\fBconnld\fR is being pushed onto a pipe end whose other end is no longer there.
.RE

.sp
.ne 2
.mk
.na
\fB\fBENOMEM\fR\fR
.ad
.RS 10n
.rt  
An internal pipe could not be created.
.RE

.sp
.ne 2
.mk
.na
\fB\fBENXIO\fR\fR
.ad
.RS 10n
.rt  
An  \fBM_HANGUP\fR message is at the stream head of the pipe onto which \fBconnld\fR is being pushed.
.RE

.sp
.ne 2
.mk
.na
\fB\fBEAGAIN\fR\fR
.ad
.RS 10n
.rt  
Internal data structures could not be allocated.
.RE

.sp
.ne 2
.mk
.na
\fB\fBENFILE\fR\fR
.ad
.RS 10n
.rt  
A file table entry could not be allocated.
.RE

.SH SEE ALSO
.sp
.LP
\fBcreat\fR(2), \fBopen\fR(2), \fBfattach\fR(3C), \fBstreamio\fR(7I) 
.sp
.LP
\fISTREAMS Programming Guide\fR