connect(3N) connect(3N)
NAME
connect - initiate a connection on a socket
SYNOPSIS
#include <sys/types.h>
#include <sys/socket.h>
connect(s, name, namelen)
int s;
struct sockaddr *name;
int namelen;
DESCRIPTION
The parameter s is a socket. If it is of type SOCK_DGRAM, connect()
specifies the peer with which the socket is to be associated; this
address is the address to which datagrams are to be sent if a
receiver is not explicitly designated; it is the only address from
which datagrams are to be received. If the socket s is of type
SOCK_STREAM, connect() attempts to make a connection to another
socket. The other socket is specified by name. name is an address
in the communications space of the socket. Each communications space
interprets the name parameter in its own way. If s is not bound, then
it will be bound to an address selected by the underlying transport
provider. Generally, stream sockets may successfully connect() only
once; datagram sockets may use connect() multiple times to change
their association. Datagram sockets may dissolve the association by
connecting to a null address.
RETURN VALUE
If the connection or binding succeeds, then 0 is returned. Otherwise
a -1 is returned and a more specific error code is stored in errno.
ERRORS
The call fails if:
EBADF s is not a valid descriptor.
ENOTSOCK s is a descriptor for a file, not a socket.
EINVAL namelen is not the size of a valid address for
the specified address family.
EADDRNOTAVAIL The specified address is not available on the
remote machine.
EAFNOSUPPORT Addresses in the specified address family cannot
be used with this socket.
EISCONN The socket is already connected.
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connect(3N) connect(3N)
ETIMEDOUT Connection establishment timed out without
establishing a connection.
ECONNREFUSED The attempt to connect was forcefully rejected.
The calling program should close(2) the socket
descriptor, and issue another socket(3N) call to
obtain a new descriptor before attempting another
connect() call.
ENETUNREACH The network is not reachable from this host.
EADDRINUSE The address is already in use.
EINPROGRESS The socket is non-blocking and the connection
cannot be completed immediately. It is possible
to select(3N) for completion by selecting the
socket for writing. However, this is only
possible if the socket STREAMS module is the
topmost module on the protocol stack with a write
service procedure. This will be the normal case.
EALREADY The socket is non-blocking and a previous
connection attempt has not yet been completed.
EINTR The connection attempt was interrupted before any
data arrived by the delivery of a signal.
ENOTSOCK The file referred to by name is not a socket.
EPROTOTYPE The file referred to by name is a socket of a
type other than type s (for example, s is a
SOCK_DGRAM socket, while name refers to a
SOCK_STREAM socket).
ENOSR There were insufficient STREAMS resources
available to complete the operation.
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 of the pathname in
name is not a directory.
ENOENT A component of the path prefix of the pathname in
name does not exist.
ENOENT The socket referred to by the pathname in name
does not exist.
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connect(3N) connect(3N)
EACCES Search permission is denied for a component of
the path prefix of the pathname in name.
ELOOP Too many symbolic links were encountered in
translating the pathname in name.
EIO An I/O error occurred while reading from or
writing to the file system.
SEE ALSO
accept(3N), connect(3N), getsockname(3N), socket(3N).
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