[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" "int 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.
.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.
.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
	46	.Fn connect "int s" "const struct sockaddr *name" "int namelen"
	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
72	by connecting to an invalid address, such as a null address.
73	.Sh RETURN VALUES
74	If the connection or binding succeeds, 0 is returned.
75	Otherwise a -1 is returned, and a more specific error
76	code is stored in
77	.Va errno .
78	.Sh ERRORS
79	The
80	.Fn connect
81	call fails if:
82	.Bl -tag -width Er
83	.It Bq Er EBADF
84	.Fa S
85	is not a valid descriptor.
86	.It Bq Er ENOTSOCK
87	.Fa S
88	is a descriptor for a file, not a socket.
89	.It Bq Er EADDRNOTAVAIL
90	The specified address is not available on this machine.
91	.It Bq Er EAFNOSUPPORT
92	Addresses in the specified address family cannot be used with this socket.
93	.It Bq Er EISCONN
94	The socket is already connected.
95	.It Bq Er ETIMEDOUT
96	Connection establishment timed out without establishing a connection.
97	.It Bq Er ECONNREFUSED
98	The attempt to connect was forcefully rejected.
99	.It Bq Er ENETUNREACH
100	The network isn't reachable from this host.
101	.It Bq Er EADDRINUSE
102	The address is already in use.
103	.It Bq Er EFAULT
104	The
105	.Fa name
106	parameter specifies an area outside
107	the process address space.
108	.It Bq Er EINPROGRESS
109	The socket is non-blocking
110	and the connection cannot
111	be completed immediately.
112	It is possible to
113	.Xr select 2
114	for completion by selecting the socket for writing.
115	.It Bq Er EALREADY
116	The socket is non-blocking
117	and a previous connection attempt
118	has not yet been completed.
119	.El
120	.Pp
121	The following errors are specific to connecting names in the UNIX domain.
122	These errors may not apply in future versions of the UNIX IPC domain.
123	.Bl -tag -width Er
124	.It Bq Er ENOTDIR
125	A component of the path prefix is not a directory.
126	.It Bq Er ENAMETOOLONG
127	A component of a pathname exceeded
128	.Dv {NAME_MAX}
129	characters, or an entire path name exceeded
130	.Dv {PATH_MAX}
131	characters.
132	.It Bq Er ENOENT
133	The named socket does not exist.
134	.It Bq Er EACCES
135	Search permission is denied for a component of the path prefix.
136	.It Bq Er EACCES
137	Write access to the named socket is denied.
138	.It Bq Er ELOOP
139	Too many symbolic links were encountered in translating the pathname.
140	.El
141	.Sh SEE ALSO
142	.Xr accept 2 ,
143	.Xr select 2 ,
144	.Xr socket 2 ,
145	.Xr getsockname 2
146	.Sh HISTORY
147	The
148	.Fn connect
149	function call appeared in
150	.Bx 4.2 .