[unix-history] / lib / libc / sys / connect.2

.\" 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.
.\"
.\"     @(#)connect.2	6.9 (Berkeley) 3/10/91
.\"
.Dd March 10, 1991
.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" "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 EADDRNOTAVAILABB
.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 EADDRNOTAVAILABB
.It Bq Er ENOTDIR
A component of the path prefix is not a directory.
.It Bq Er EINVAL
The pathname contains a character with the high-order bit set.
.It Bq Er ENAMETOOLONG
A component of a pathname exceeded 255 characters,
or an entire path name exceeded 1023 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
.Nm
function call appeared in
.Bx 4.2 .
Commit	Line	Data
15637ed4 RG	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	.\" @(#)connect.2 6.9 (Berkeley) 3/10/91
	33	.\"
	34	.Dd March 10, 1991
	35	.Dt CONNECT 2
	36	.Os BSD 4.2
	37	.Sh NAME
	38	.Nm connect
	39	.Nd initiate a connection on a socket
	40	.Sh SYNOPSIS
	41	.Fd #include <sys/types.h>
	42	.Fd #include <sys/socket.h>
	43	.Ft int
	44	.Fn connect "int s" "struct sockaddr *name" "int namelen"
	45	.Sh DESCRIPTION
	46	The parameter
	47	.Fa s
	48	is a socket.
	49	If it is of type
	50	.Dv SOCK_DGRAM ,
	51	this call specifies the peer with which the socket is to be associated;
	52	this address is that to which datagrams are to be sent,
	53	and the only address from which datagrams are to be received.
	54	If the socket is of type
	55	.Dv SOCK_STREAM ,
	56	this call attempts to make a connection to
	57	another socket.
	58	The other socket is specified by
	59	.Fa name ,
	60	which is an address in the communications space of the socket.
	61	Each communications space interprets the
	62	.Fa name
	63	parameter in its own way.
	64	Generally, stream sockets may successfully
65	.Fn connect
66	only once; datagram sockets may use
67	.Fn connect
68	multiple times to change their association.
69	Datagram sockets may dissolve the association
70	by connecting to an invalid address, such as a null address.
71	.Sh RETURN VALUES
72	If the connection or binding succeeds, 0 is returned.
73	Otherwise a -1 is returned, and a more specific error
74	code is stored in
75	.Va errno .
76	.Sh ERRORS
77	The
78	.Fn connect
79	call fails if:
80	.Bl -tag -width EADDRNOTAVAILABB
81	.It Bq Er EBADF
82	.Fa S
83	is not a valid descriptor.
84	.It Bq Er ENOTSOCK
85	.Fa S
86	is a descriptor for a file, not a socket.
87	.It Bq Er EADDRNOTAVAIL
88	The specified address is not available on this machine.
89	.It Bq Er EAFNOSUPPORT
90	Addresses in the specified address family cannot be used with this socket.
91	.It Bq Er EISCONN
92	The socket is already connected.
93	.It Bq Er ETIMEDOUT
94	Connection establishment timed out without establishing a connection.
95	.It Bq Er ECONNREFUSED
96	The attempt to connect was forcefully rejected.
97	.It Bq Er ENETUNREACH
98	The network isn't reachable from this host.
99	.It Bq Er EADDRINUSE
100	The address is already in use.
101	.It Bq Er EFAULT
102	The
103	.Fa name
104	parameter specifies an area outside
105	the process address space.
106	.It Bq Er EINPROGRESS
107	The socket is non-blocking
108	and the connection cannot
109	be completed immediately.
110	It is possible to
111	.Xr select 2
112	for completion by selecting the socket for writing.
113	.It Bq Er EALREADY
114	The socket is non-blocking
115	and a previous connection attempt
116	has not yet been completed.
117	.El
118	.Pp
119	The following errors are specific to connecting names in the UNIX domain.
120	These errors may not apply in future versions of the UNIX IPC domain.
121	.Bl -tag -width EADDRNOTAVAILABB
122	.It Bq Er ENOTDIR
123	A component of the path prefix is not a directory.
124	.It Bq Er EINVAL
125	The pathname contains a character with the high-order bit set.
126	.It Bq Er ENAMETOOLONG
127	A component of a pathname exceeded 255 characters,
128	or an entire path name exceeded 1023 characters.
129	.It Bq Er ENOENT
130	The named socket does not exist.
131	.It Bq Er EACCES
132	Search permission is denied for a component of the path prefix.
133	.It Bq Er EACCES
134	Write access to the named socket is denied.
135	.It Bq Er ELOOP
136	Too many symbolic links were encountered in translating the pathname.
137	.El
138	.Sh SEE ALSO
139	.Xr accept 2 ,
140	.Xr select 2 ,
141	.Xr socket 2 ,
142	.Xr getsockname 2
143	.Sh HISTORY
144	The
145	.Nm
146	function call appeared in
147	.Bx 4.2 .