The parameter
s
is a socket.
If it is of type
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
SOCK_STREAM,
this call attempts to make a connection to
another socket.
The other socket is specified by
name,
which is an address in the communications space of the socket.
namelen
indicates the amount of space pointed to by
name,
in bytes.
Each communications space interprets the
name
parameter in its own way.
Generally, stream sockets may use
connect();
only once; datagram sockets may use
connect();
multiple times to change their association.
Datagram sockets may dissolve the association
by connecting to an invalid address, such as a null address.
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
errno.
ERRORS
The
connect();
call fails if:
[EBADF]
S
is not a valid descriptor.
[ENOTSOCK]
S
is a descriptor for a file, not a socket.
[EADDRNOTAVAIL]
The specified address is not available on this machine.
[EAFNOSUPPORT]
Addresses in the specified address family cannot be used with this socket.
[EISCONN]
The socket is already connected.
[ETIMEDOUT]
Connection establishment timed out without establishing a connection.
[EINVAL]
A TCP connection with a local broadcast, the all-ones or a
multicast address as the peer was attempted.
[ECONNREFUSED]
The attempt to connect was forcefully rejected.
[EHOSTUNREACH]
The destination address specified an unreachable host.
[EINTR]
A connect was interrupted before it succeeded
by the delivery of a signal.
[ENETUNREACH]
The network isn't reachable from this host.
[EADDRINUSE]
The address is already in use.
[EFAULT]
The
name
parameter specifies an area outside
the process address space.
[EINPROGRESS]
The socket is non-blocking
and the connection cannot
be completed immediately.
It is possible to
select(2)
or
poll(2)
for completion by selecting the socket for writing, and also use
getsockopt(2)
with
SO_ERROR
to check for error conditions.
[EALREADY]
The socket is non-blocking
and a previous connection attempt
has not yet been completed.
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.
[ENOTDIR]
A component of the path prefix is not a directory.
[ENAMETOOLONG]
A component of a pathname exceeded
{NAME_MAX}
characters, or an entire path name exceeded
{PATH_MAX}
characters.
[ENOENT]
The named socket does not exist.
[EACCES]
Search permission is denied for a component of the path prefix.
[EACCES]
Write access to the named socket is denied.
[ELOOP]
Too many symbolic links were encountered in translating the pathname.
[EPROTOTYPE]
The file described by
name
is of a different type than
s.
E.g.,
s
may be of type
SOCK_STREAM
whereas
name
may refer to a socket of type
SOCK_DGRAM.