connect - initiate a connection on a socket
connect(s, name, namelen)
struct sockaddr *name;
The parameter s is a socket. If it is of type SOCK_DGRAM, then 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, then 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. Each communications space interprets the name parameter in its own
way. 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 an invalid address, such as a null address.
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.
The 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
[EISCONN] The socket is already connected.
[ETIMEDOUT] Connection establishment timed out without establishing a connection.
[ECONNREFUSED] The attempt to connect was forcefully rejected.
[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
[EINPROGRESS] The socket is non-blocking and the connection cannot be completed
immediately. It is possible to select(2) for completion by selecting
the socket for writing.
[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.
[EINVAL] The pathname contains a character with the high-order bit set.
[ENAMETOOLONG] A component of a pathname exceeded 255 characters, or an entire path name
exceeded 1023 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.
accept(2), select(2), socket(2), getsockname(2)
4.2 Berkeley Distribution May 22, 1986 CONNECT(2)