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

     connect --	initiate a connection on a socket

     #include <sys/types.h>
     #include <sys/socket.h>

     connect(int s, const struct sockaddr *name, int 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.  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.

     In	the non-threaded library connect() is implemented as the connect

     In	the threaded library, the connect syscall is assembled to
     _thread_sys_connect() and connect() is implemented	as a function which
     locks s for read and write, then calls _thread_sys_connect().  If the
     call to _thread_sys_connect() would block,	a context switch is performed.
     Before returning, connect() unlocks s.

     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 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.

     [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) 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.

     [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

     [EACCES]	       Write access to the named socket	is denied.

     [ELOOP]	       Too many	symbolic links were encountered	in translating
		       the pathname.

     accept(2),	getpeername(2),	getsockname(2),	select(2), socket(2)

     The connect() function call appeared in 4.2BSD.

4.2 Berkeley Distribution	 June 4, 1993	     4.2 Berkeley Distribution


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