[apple/xnu.git] / bsd / man / man2 / connect.2

.\"	$NetBSD: connect.2,v 1.8 1995/10/12 15:40:48 jtc Exp $
.\"
.\" Copyright (c) 1983, 1993
.\"	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.
.\"
.\"     @(#)connect.2	8.1 (Berkeley) 6/4/93
.\"
.Dd June 4, 1993
.Dt CONNECT 2
.Os BSD 4.2
.Sh NAME
.Nm connect
.Nd initiate a connection on a socket
.Sh SYNOPSIS
.Fd #include <sys/types.h>
.Fd #include <sys/socket.h>
.Ft int
.Fn connect "int s" "const struct sockaddr *name" "socklen_t namelen"
.Sh DESCRIPTION
The parameter
.Fa s
is a socket.
If it is of type
.Dv 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
.Dv SOCK_STREAM ,
this call attempts to make a connection to
another socket.
The other socket is specified by
.Fa name ,
which is an address in the communications space of the socket.
Each communications space interprets the
.Fa name
parameter in its own way.
Generally, stream sockets may successfully
.Fn connect
only once; datagram sockets may use
.Fn connect
multiple times to change their association.
Datagram sockets may dissolve the association
by connecting to an invalid address, such as a null address 
or an address with 
the address family set to 
.Dv AF_UNSPEC 
(the error 
.Dv EAFNOSUPPORT 
will be harmlessly returned).
.Sh RETURN VALUES
If the connection or binding succeeds, 0 is returned.
Otherwise a -1 is returned, and a more specific error
code is stored in
.Va errno .
.Sh ERRORS
The
.Fn connect
call fails if:
.Bl -tag -width Er
.It Bq Er EBADF
.Fa S
is not a valid descriptor.
.It Bq Er ENOTSOCK
.Fa S
is a descriptor for a file, not a socket.
.It Bq Er EADDRNOTAVAIL
The specified address is not available on this machine.
.It Bq Er EAFNOSUPPORT
Addresses in the specified address family cannot be used with this socket.
.It Bq Er EISCONN
The socket is already connected.
.It Bq Er ETIMEDOUT
Connection establishment timed out without establishing a connection.
.It Bq Er ECONNREFUSED
The attempt to connect was forcefully rejected.
.It Bq Er ENETUNREACH
The network isn't reachable from this host.
.It Bq Er EADDRINUSE
The address is already in use.
.It Bq Er EFAULT
The
.Fa name
parameter specifies an area outside
the process address space.
.It Bq Er EINPROGRESS
The socket is non-blocking 
and the connection cannot
be completed immediately.
It is possible to
.Xr select 2
for completion by selecting the socket for writing.
.It Bq Er EALREADY
The socket is non-blocking
and a previous connection attempt
has not yet been completed.
.It Bq Er EACCES
The destination address is a broadcast address and the 
socket option 
.Dv SO_BROADCAST 
is not set.
.El
.Pp
The following errors are specific to connecting names in the UNIX domain.
These errors may not apply in future versions of the UNIX IPC domain.
.Bl -tag -width Er
.It Bq Er ENOTDIR
A component of the path prefix is not a directory.
.It Bq Er ENAMETOOLONG
A component of a pathname exceeded 
.Dv {NAME_MAX}
characters, or an entire path name exceeded 
.Dv {PATH_MAX}
characters.
.It Bq Er ENOENT
The named socket does not exist.
.It Bq Er EACCES
Search permission is denied for a component of the path prefix.
.It Bq Er EACCES
Write access to the named socket is denied.
.It Bq Er ELOOP
Too many symbolic links were encountered in translating the pathname.
.El
.Sh SEE ALSO
.Xr accept 2 ,
.Xr select 2 ,
.Xr socket 2 ,
.Xr getsockname 2
.Sh HISTORY
The
.Fn connect
function call appeared in
.Bx 4.2 .
Commit	Line	Data
9bccf70c A	1	.\" $NetBSD: connect.2,v 1.8 1995/10/12 15:40:48 jtc Exp $
	2	.\"
	3	.\" Copyright (c) 1983, 1993
	4	.\" The Regents of the University of California. All rights reserved.
	5	.\"
	6	.\" Redistribution and use in source and binary forms, with or without
	7	.\" modification, are permitted provided that the following conditions
	8	.\" are met:
	9	.\" 1. Redistributions of source code must retain the above copyright
	10	.\" notice, this list of conditions and the following disclaimer.
	11	.\" 2. Redistributions in binary form must reproduce the above copyright
	12	.\" notice, this list of conditions and the following disclaimer in the
	13	.\" documentation and/or other materials provided with the distribution.
	14	.\" 3. All advertising materials mentioning features or use of this software
	15	.\" must display the following acknowledgement:
	16	.\" This product includes software developed by the University of
	17	.\" California, Berkeley and its contributors.
	18	.\" 4. Neither the name of the University nor the names of its contributors
	19	.\" may be used to endorse or promote products derived from this software
	20	.\" without specific prior written permission.
	21	.\"
	22	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	23	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	24	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	25	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	26	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	27	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	28	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	29	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	30	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	31	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	32	.\" SUCH DAMAGE.
	33	.\"
	34	.\" @(#)connect.2 8.1 (Berkeley) 6/4/93
	35	.\"
	36	.Dd June 4, 1993
	37	.Dt CONNECT 2
	38	.Os BSD 4.2
	39	.Sh NAME
	40	.Nm connect
	41	.Nd initiate a connection on a socket
	42	.Sh SYNOPSIS
	43	.Fd #include <sys/types.h>
	44	.Fd #include <sys/socket.h>
	45	.Ft int
91447636	46	.Fn connect "int s" "const struct sockaddr *name" "socklen_t namelen"
9bccf70c A	47	.Sh DESCRIPTION
	48	The parameter
	49	.Fa s
	50	is a socket.
	51	If it is of type
	52	.Dv SOCK_DGRAM ,
	53	this call specifies the peer with which the socket is to be associated;
	54	this address is that to which datagrams are to be sent,
	55	and the only address from which datagrams are to be received.
	56	If the socket is of type
	57	.Dv SOCK_STREAM ,
	58	this call attempts to make a connection to
	59	another socket.
	60	The other socket is specified by
	61	.Fa name ,
	62	which is an address in the communications space of the socket.
	63	Each communications space interprets the
	64	.Fa name
	65	parameter in its own way.
	66	Generally, stream sockets may successfully
	67	.Fn connect
	68	only once; datagram sockets may use
	69	.Fn connect
	70	multiple times to change their association.
	71	Datagram sockets may dissolve the association
55e303ae A	72	by connecting to an invalid address, such as a null address
55e303ae A	73	or an address with
91447636 A	74	the address family set to
	75	.Dv AF_UNSPEC
	76	(the error
	77	.Dv EAFNOSUPPORT
	78	will be harmlessly returned).
9bccf70c A	79	.Sh RETURN VALUES
	80	If the connection or binding succeeds, 0 is returned.
	81	Otherwise a -1 is returned, and a more specific error
	82	code is stored in
	83	.Va errno .
	84	.Sh ERRORS
	85	The
	86	.Fn connect
	87	call fails if:
	88	.Bl -tag -width Er
	89	.It Bq Er EBADF
	90	.Fa S
	91	is not a valid descriptor.
	92	.It Bq Er ENOTSOCK
	93	.Fa S
	94	is a descriptor for a file, not a socket.
	95	.It Bq Er EADDRNOTAVAIL
	96	The specified address is not available on this machine.
	97	.It Bq Er EAFNOSUPPORT
	98	Addresses in the specified address family cannot be used with this socket.
	99	.It Bq Er EISCONN
	100	The socket is already connected.
	101	.It Bq Er ETIMEDOUT
	102	Connection establishment timed out without establishing a connection.
	103	.It Bq Er ECONNREFUSED
	104	The attempt to connect was forcefully rejected.
	105	.It Bq Er ENETUNREACH
	106	The network isn't reachable from this host.
	107	.It Bq Er EADDRINUSE
	108	The address is already in use.
	109	.It Bq Er EFAULT
	110	The
	111	.Fa name
	112	parameter specifies an area outside
	113	the process address space.
	114	.It Bq Er EINPROGRESS
	115	The socket is non-blocking
	116	and the connection cannot
	117	be completed immediately.
	118	It is possible to
	119	.Xr select 2
	120	for completion by selecting the socket for writing.
	121	.It Bq Er EALREADY
	122	The socket is non-blocking
	123	and a previous connection attempt
	124	has not yet been completed.
91447636 A	125	.It Bq Er EACCES
	126	The destination address is a broadcast address and the
	127	socket option
	128	.Dv SO_BROADCAST
	129	is not set.
9bccf70c A	130	.El
	131	.Pp
	132	The following errors are specific to connecting names in the UNIX domain.
	133	These errors may not apply in future versions of the UNIX IPC domain.
	134	.Bl -tag -width Er
	135	.It Bq Er ENOTDIR
	136	A component of the path prefix is not a directory.
	137	.It Bq Er ENAMETOOLONG
	138	A component of a pathname exceeded
	139	.Dv {NAME_MAX}
	140	characters, or an entire path name exceeded
	141	.Dv {PATH_MAX}
	142	characters.
	143	.It Bq Er ENOENT
	144	The named socket does not exist.
	145	.It Bq Er EACCES
	146	Search permission is denied for a component of the path prefix.
	147	.It Bq Er EACCES
	148	Write access to the named socket is denied.
	149	.It Bq Er ELOOP
	150	Too many symbolic links were encountered in translating the pathname.
	151	.El
	152	.Sh SEE ALSO
	153	.Xr accept 2 ,
	154	.Xr select 2 ,
	155	.Xr socket 2 ,
	156	.Xr getsockname 2
	157	.Sh HISTORY
	158	The
	159	.Fn connect
	160	function call appeared in
	161	.Bx 4.2 .