1.\" Copyright (c) 1983 The Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" from: @(#)connect.2 6.9 (Berkeley) 3/10/91 33.\" $Id: connect.2,v 1.4 1993/11/29 21:25:03 jtc Exp $ 34.\" 35.Dd March 10, 1991 36.Dt CONNECT 2 37.Os BSD 4.2 38.Sh NAME 39.Nm connect 40.Nd initiate a connection on a socket 41.Sh SYNOPSIS 42.Fd #include <sys/types.h> 43.Fd #include <sys/socket.h> 44.Ft int 45.Fn connect "int s" "struct sockaddr *name" "int namelen" 46.Sh DESCRIPTION 47The parameter 48.Fa s 49is a socket. 50If it is of type 51.Dv SOCK_DGRAM , 52this call specifies the peer with which the socket is to be associated; 53this address is that to which datagrams are to be sent, 54and the only address from which datagrams are to be received. 55If the socket is of type 56.Dv SOCK_STREAM , 57this call attempts to make a connection to 58another socket. 59The other socket is specified by 60.Fa name , 61which is an address in the communications space of the socket. 62Each communications space interprets the 63.Fa name 64parameter in its own way. 65Generally, stream sockets may successfully 66.Fn connect 67only once; datagram sockets may use 68.Fn connect 69multiple times to change their association. 70Datagram sockets may dissolve the association 71by connecting to an invalid address, such as a null address. 72.Sh RETURN VALUES 73If the connection or binding succeeds, 0 is returned. 74Otherwise a -1 is returned, and a more specific error 75code is stored in 76.Va errno . 77.Sh ERRORS 78The 79.Fn connect 80call fails if: 81.Bl -tag -width Er 82.It Bq Er EBADF 83.Fa S 84is not a valid descriptor. 85.It Bq Er ENOTSOCK 86.Fa S 87is a descriptor for a file, not a socket. 88.It Bq Er EADDRNOTAVAIL 89The specified address is not available on this machine. 90.It Bq Er EAFNOSUPPORT 91Addresses in the specified address family cannot be used with this socket. 92.It Bq Er EISCONN 93The socket is already connected. 94.It Bq Er ETIMEDOUT 95Connection establishment timed out without establishing a connection. 96.It Bq Er ECONNREFUSED 97The attempt to connect was forcefully rejected. 98.It Bq Er ENETUNREACH 99The network isn't reachable from this host. 100.It Bq Er EADDRINUSE 101The address is already in use. 102.It Bq Er EFAULT 103The 104.Fa name 105parameter specifies an area outside 106the process address space. 107.It Bq Er EINPROGRESS 108The socket is non-blocking 109and the connection cannot 110be completed immediately. 111It is possible to 112.Xr select 2 113for completion by selecting the socket for writing. 114.It Bq Er EALREADY 115The socket is non-blocking 116and a previous connection attempt 117has not yet been completed. 118.El 119.Pp 120The following errors are specific to connecting names in the UNIX domain. 121These errors may not apply in future versions of the UNIX IPC domain. 122.Bl -tag -width Er 123.It Bq Er ENOTDIR 124A component of the path prefix is not a directory. 125.It Bq Er EINVAL 126The pathname contains a character with the high-order bit set. 127.It Bq Er ENAMETOOLONG 128A component of a pathname exceeded 255 characters, 129or an entire path name exceeded 1023 characters. 130.It Bq Er ENOENT 131The named socket does not exist. 132.It Bq Er EACCES 133Search permission is denied for a component of the path prefix. 134.It Bq Er EACCES 135Write access to the named socket is denied. 136.It Bq Er ELOOP 137Too many symbolic links were encountered in translating the pathname. 138.El 139.Sh SEE ALSO 140.Xr accept 2 , 141.Xr select 2 , 142.Xr socket 2 , 143.Xr getsockname 2 144.Sh HISTORY 145The 146.Fn connect 147function call appeared in 148.Bx 4.2 . 149