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# connect

    CONNECT(2)                    System Calls Manual                   CONNECT(2)

    NAME
         connect - initiate a connection on a socket

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

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

    DESCRIPTION
         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 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
         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 establish-
                            ing 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.

         [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 pro-
                            cess 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} charac-
                            ters, or an entire path name exceeded {PATH_MAX} char-
                            acters.

         [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 translat-
                            ing the pathname.

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

    HISTORY
         The connect() function call appeared in 4.2BSD.

    BSD                            February 15, 1999                           BSD

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