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CONNECT(2)		    BSD	System Calls Manual		    CONNECT(2)

     connect --	initiate a connection on a socket

     Standard C	Library	(libc, -lc)

     #include <sys/socket.h>

     connect(int s, const struct sockaddr *name, socklen_t namelen);

     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	ad-
     dress 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 commu-
     nications 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 success-
     fully connect() only once;	datagram sockets may use connect() multiple
     times to change their association.	 Datagram sockets may dissolve the as-
     sociation by connecting to	an invalid address, such as a null address.

     If	a connect() call is interrupted	by a signal, it	will return with errno
     set to EINTR and the connection attempt will proceed as if	the socket was
     non-blocking.  Subsequent calls to	connect() will set errno to EALREADY.

     If	the connection or binding succeeds, 0 is returned.  Otherwise a	-1 is
     returned, and a more specific error code is stored	in errno.

     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 ma-

     [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 establish-
			ing 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	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 or polling the
			socket for writing.  The success or failure of the
			connect	operation may be determined by using
			getsockopt(2) to read the socket error status with the
			SO_ERROR option	at the SOL_SOCKET level.  The returned
			socket error status is zero on success,	or one of the
			error codes listed here	on failure.

     [EALREADY]		Either the socket is non-blocking mode or a previous
			call to	connect() was interrupted by a signal, and the
			connection attempt has not yet been completed.

     [EINTR]		The connection attempt was interrupted by a signal.

     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} charac-
			ters, or an entire path	name exceeded {PATH_MAX} char-

     [ENOENT]		The named socket does not exist.

     [EACCES]		Search permission is denied for	a component of the
			path prefix, or	write access to	the named socket is

     [ELOOP]		Too many symbolic links	were encountered in translat-
			ing the	pathname.

     accept(2),	getsockname(2),	getsockopt(2), poll(2),	select(2), socket(2)

     The connect() function call appeared in 4.2BSD.

BSD				 May 18, 2004				   BSD


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