1.\" Copyright (c) 1983, 1993 2.\" The Regents of the University of California. 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.\" @(#)connect.2 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD$ 34.\" 35.Dd June 4, 1993 36.Dt CONNECT 2 37.Os 38.Sh NAME 39.Nm connect 40.Nd initiate a connection on a socket 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In sys/types.h 45.In sys/socket.h 46.Ft int 47.Fn connect "int s" "const struct sockaddr *name" "socklen_t namelen" 48.Sh DESCRIPTION 49The 50.Fa s 51argument 52is a socket. 53If it is of type 54.Dv SOCK_DGRAM , 55this call specifies the peer with which the socket is to be associated; 56this address is that to which datagrams are to be sent, 57and the only address from which datagrams are to be received. 58If the socket is of type 59.Dv SOCK_STREAM , 60this call attempts to make a connection to 61another socket. 62The other socket is specified by 63.Fa name , 64which is an address in the communications space of the socket. 65Each communications space interprets the 66.Fa name 67argument in its own way. 68Generally, stream sockets may successfully 69.Fn connect 70only once; datagram sockets may use 71.Fn connect 72multiple times to change their association. 73Datagram sockets may dissolve the association 74by connecting to an invalid address, such as a null address. 75.Sh RETURN VALUES 76.Rv -std connect 77.Sh ERRORS 78The 79.Fn connect 80system call fails if: 81.Bl -tag -width Er 82.It Bq Er EBADF 83The 84.Fa s 85argument 86is not a valid descriptor. 87.It Bq Er ENOTSOCK 88The 89.Fa s 90argument 91is a descriptor for a file, not a socket. 92.It Bq Er EADDRNOTAVAIL 93The specified address is not available on this machine. 94.It Bq Er EAFNOSUPPORT 95Addresses in the specified address family cannot be used with this socket. 96.It Bq Er EISCONN 97The socket is already connected. 98.It Bq Er ETIMEDOUT 99Connection establishment timed out without establishing a connection. 100.It Bq Er ECONNREFUSED 101The attempt to connect was forcefully rejected. 102.It Bq Er ENETUNREACH 103The network is not reachable from this host. 104.It Bq Er EHOSTUNREACH 105The remote host is not reachable from this host. 106.It Bq Er EADDRINUSE 107The address is already in use. 108.It Bq Er EFAULT 109The 110.Fa name 111argument specifies an area outside 112the process address space. 113.It Bq Er EINPROGRESS 114The socket is non-blocking 115and the connection cannot 116be completed immediately. 117It is possible to 118.Xr select 2 119for completion by selecting the socket for writing. 120.It Bq Er EINTR 121The connection attempt was interrupted by the delivery of a signal. 122The connection will be established in the background, 123as in the case of 124.Er EINPROGRESS . 125.It Bq Er EALREADY 126A previous connection attempt has not yet been completed. 127.It Bq Er EACCES 128An attempt is made to connect to a broadcast address (obtained through the 129.Dv INADDR_BROADCAST 130constant or the 131.Dv INADDR_NONE 132return value) through a socket that does not provide broadcast functionality. 133.El 134.Pp 135The following errors are specific to connecting names in the UNIX domain. 136These errors may not apply in future versions of the UNIX IPC domain. 137.Bl -tag -width Er 138.It Bq Er ENOTDIR 139A component of the path prefix is not a directory. 140.It Bq Er ENAMETOOLONG 141A component of a pathname exceeded 255 characters, 142or an entire path name exceeded 1023 characters. 143.It Bq Er ENOENT 144The named socket does not exist. 145.It Bq Er EACCES 146Search permission is denied for a component of the path prefix. 147.It Bq Er EACCES 148Write access to the named socket is denied. 149.It Bq Er ELOOP 150Too many symbolic links were encountered in translating the pathname. 151.El 152.Sh SEE ALSO 153.Xr accept 2 , 154.Xr getpeername 2 , 155.Xr getsockname 2 , 156.Xr select 2 , 157.Xr socket 2 158.Sh HISTORY 159The 160.Fn connect 161system call appeared in 162.Bx 4.2 . 163