.\" Hey Emacs! This file is -*- nroff -*- source. .\" .\" Copyright 1993 Rickard E. Faith (faith@cs.unc.edu) .\" Portions extracted from /usr/include/sys/socket.h, which does not have .\" any authorship information in it. It is probably available under the GPL. .\" .\" Permission is granted to make and distribute verbatim copies of this .\" manual provided the copyright notice and this permission notice are .\" preserved on all copies. .\" .\" Permission is granted to copy and distribute modified versions of this .\" manual under the conditions for verbatim copying, provided that the .\" entire resulting derived work is distributed under the terms of a .\" permission notice identical to this one .\" .\" Since the Linux kernel and libraries are constantly changing, this .\" manual page may be incorrect or out-of-date. The author(s) assume no .\" responsibility for errors or omissions, or for damages resulting from .\" the use of the information contained herein. The author(s) may not .\" have taken the same level of care in the production of this manual, .\" which is licensed free of charge, as they might when working .\" professionally. .\" .\" Formatted or processed versions of this manual, if unaccompanied by .\" the source, must acknowledge the copyright and authors of this work. .\" .\" .\" Other portions are from the 6.9 (Berkeley) 3/10/91 man page: .\" .\" Copyright (c) 1983 The Regents of the University of California. .\" All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by the University of .\" California, Berkeley and its contributors. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" Modified Fri Jan 31 16:22:26 1997 by Eric S. Raymond .\" .TH CONNECT 2 "23 July 1993" "Linux 0.99.11" "Linux Programmer's Manual" .SH NAME connect \- initiate a connection on a socket .SH SYNOPSIS .B #include .br .B #include .sp .BI "int connect(int " sockfd ", struct sockaddr *" serv_addr ", int .BI " addrlen ); .SH DESCRIPTION The parameter .I sockfd is a socket. If it is of type .BR SOCK_DGRAM , this call specifies the peer with which the socket is to be associated; this address is that to which datagrams are to be sent, and the only address from which datagrams are to be received. If the socket is of type .B SOCK_STREAM , this call attempts to make a connection to another socket. The other socket is specified by .BR serv_addr , which is an address in the communications space of the socket. Each communications space interprets the .BR serv_addr , parameter in its own way. Generally, stream sockets may successfully .B connect only once; datagram sockets may use .B connect multiple times to change their association. Datagram sockets may dissolve the association by connecting to an invalid address, such as a null address. .SH "RETURN VALUE" If the connection or binding succeeds, zero is returned. On error, \-1 is returned, and .I errno is set appropriately. .SH ERRORS The following are general socket errors only. There may be other domain-specific error codes. .TP .B EBADF Bad descriptor. .TP .B EFAULT The socket structure address is outside your address space. .TP .B ENOTSOCK The descriptor is not associated with a socket. .TP .B EISCONN The socket is already connected. .TP .B ECONNREFUSED Connection refused at server. .TP .B ETIMEDOUT Timeout while attempting connection. .TP .B ENETUNREACH Network is unreachable. .TP .B EADDRINUSE Address is already in use. .TP .B EINPROGRESS The socket is non-blocking and the connection cannot be completed immediately. It is possible to .BR select (2) for completion by selecting the socket for writing. After \fBselect\fR indicates writability, use .BR getsockopt (2) to read the \fBSO_ERROR\fR option at level \fBSOL_SOCKET\fR to determine whether \fBconnect\fR completed successfully (\fBSO_ERROR\fR is zero) or unsuccessfully (\fBSO_ERROR\fR is one of the usual error codes listed above, explaining the reason for the failure). .TP .B EALREADY The socket is non-blocking and a previous connection attempt has not yet been completed. .SH CONFORMING TO SVr4, 4.4BSD (the .B connect function first appeared in BSD 4.2). SVr4 documents additional general error codes EADDRNOTAVAIL, EINVAL, EAFNOSUPPORT, EALREADY, EINTR, EPROTOTYPE, ENOSR. It also documents many additional error conditions not described here. .SH "SEE ALSO" .BR accept "(2), " bind "(2), " listen "(2), " .BR socket "(2), " getsockname (2)