236 lines
6.8 KiB
Groff
236 lines
6.8 KiB
Groff
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.\" $NetBSD: connect.2,v 1.8 1995/10/12 15:40:48 jtc Exp $
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.\"
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.\" Copyright (c) 1983, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)connect.2 8.1 (Berkeley) 6/4/93
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.\"
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.Dd March 18, 2015
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.Dt CONNECT 2
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.Os BSD 4.2
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.Sh NAME
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.Nm connect
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.Nd initiate a connection on a socket
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.Sh SYNOPSIS
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.Fd #include <sys/types.h>
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.Fd #include <sys/socket.h>
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.Ft int
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.Fo connect
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.Fa "int socket"
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.Fa "const struct sockaddr *address"
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.Fa "socklen_t address_len"
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.Fc
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.Sh DESCRIPTION
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The parameter
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.Fa socket
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is a socket.
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If it is of type
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.Dv SOCK_DGRAM ,
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this call specifies the peer with which the socket is to be associated;
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this address is that to which datagrams are to be sent,
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and the only address from which datagrams are to be received.
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If the socket is of type
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.Dv SOCK_STREAM ,
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this call attempts to make a connection to
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another socket.
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The other socket is specified by
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.Fa address ,
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which is an address in the communications space of the socket.
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.Pp
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Each communications space interprets the
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.Fa address
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parameter in its own way.
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Generally, stream sockets may successfully
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.Fn connect
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only once; datagram sockets may use
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.Fn connect
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multiple times to change their association.
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Datagram sockets may dissolve the association
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by calling
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.Xr disconnectx 2 ,
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or by connecting to an invalid address, such as a null address
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or an address with
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the address family set to
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.Dv AF_UNSPEC
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(the error
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.Dv EAFNOSUPPORT
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will be harmlessly returned).
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.Sh RETURN VALUES
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Upon successful completion, a value of 0 is returned.
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Otherwise, a value of -1 is returned and the global integer variable
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.Va errno
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is set to indicate the error.
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.Sh ERRORS
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The
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.Fn connect
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system call will fail if:
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.Bl -tag -width Er
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.\" ==========
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.It Bq Er EACCES
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The destination address is a broadcast address and the
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socket option
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.Dv SO_BROADCAST
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is not set.
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.\" ==========
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.It Bq Er EADDRINUSE
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The address is already in use.
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.\" ==========
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.It Bq Er EADDRNOTAVAIL
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The specified address is not available on this machine.
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.\" ==========
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.It Bq Er EAFNOSUPPORT
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Addresses in the specified address family cannot be used with this socket.
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.\" ==========
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.It Bq Er EALREADY
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The socket is non-blocking
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and a previous connection attempt
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has not yet been completed.
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.\" ==========
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.It Bq Er EBADF
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.Fa socket
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is not a valid descriptor.
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.\" ==========
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.It Bq Er ECONNREFUSED
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The attempt to connect was ignored
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(because the target is not listening for connections)
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or explicitly rejected.
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.\" ==========
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.It Bq Er EFAULT
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The
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.Fa address
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parameter specifies an area outside
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the process address space.
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.\" ==========
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.It Bq Er EHOSTUNREACH
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The target host cannot be reached (e.g., down, disconnected).
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.\" ==========
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.It Bq Er EINPROGRESS
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The socket is non-blocking
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and the connection cannot
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be completed immediately.
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It is possible to
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.Xr select 2
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for completion by selecting the socket for writing.
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.\" ==========
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.It Bq Er EINTR
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Its execution was interrupted by a signal.
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.\" ==========
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.It Bq Er EINVAL
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An invalid argument was detected
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(e.g.,
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.Fa address_len
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is not valid for the address family,
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the specified address family is invalid).
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.\" ==========
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.It Bq Er EISCONN
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The socket is already connected.
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.\" ==========
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.It Bq Er ENETDOWN
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The local network interface is not functioning.
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.\" ==========
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.It Bq Er ENETUNREACH
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The network isn't reachable from this host.
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.\" ==========
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.It Bq Er ENOBUFS
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The system call was unable to allocate a needed memory buffer.
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.\" ==========
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.It Bq Er ENOTSOCK
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.Fa socket
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is not a file descriptor for a socket.
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.\" ==========
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.It Bq Er EOPNOTSUPP
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Because
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.Fa socket
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is listening, no connection is allowed.
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.\" ==========
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.It Bq Er EPROTOTYPE
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.Fa address
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has a different type than the socket
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that is bound to the specified peer address.
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.\" ==========
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.It Bq Er ETIMEDOUT
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Connection establishment timed out without establishing a connection.
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.\" ==========
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.It Bq Er ECONNRESET
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Remote host reset the connection request.
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.El
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.Pp
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The following errors are specific to connecting names in the UNIX domain.
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These errors may not apply in future versions of the UNIX IPC domain.
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.Bl -tag -width Er
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.\" ==========
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.It Bq Er EACCES
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Search permission is denied for a component of the path prefix.
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.\" ==========
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.It Bq Er EACCES
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Write access to the named socket is denied.
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.\" ==========
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.It Bq Er EIO
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An I/O error occurred while reading from or writing to the file system.
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.\" ==========
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.It Bq Er ELOOP
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Too many symbolic links were encountered in translating the pathname.
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This is taken to be indicative of a looping symbolic link.
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.\" ==========
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.It Bq Er ENAMETOOLONG
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A component of a pathname exceeded
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.Dv {NAME_MAX}
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characters, or an entire path name exceeded
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.Dv {PATH_MAX}
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characters.
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.\" ==========
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.It Bq Er ENOENT
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The named socket does not exist.
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.\" ==========
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.It Bq Er ENOTDIR
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A component of the path prefix is not a directory.
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.El
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.Sh LEGACY SYNOPSIS
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.Fd #include <sys/types.h>
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.Fd #include <sys/socket.h>
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.Pp
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The include file
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.In sys/types.h
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is necessary.
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.Sh SEE ALSO
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.Xr accept 2 ,
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.Xr connectx 2 ,
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.Xr disconnectx 2 ,
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.Xr getsockname 2 ,
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.Xr select 2 ,
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.Xr socket 2 ,
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.Xr compat 5
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.Sh HISTORY
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The
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.Fn connect
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function call appeared in
|
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|
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.Bx 4.2 .
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