NAME    [Toc]    [Back]

     connect - initiate a connection on a socket

LIBRARY    [Toc]    [Back]

     Standard C Library (libc, -lc)

SYNOPSIS    [Toc]    [Back]

     #include <sys/socket.h>

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

DESCRIPTION    [Toc]    [Back]

     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 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.

RETURN VALUES    [Toc]    [Back]

     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    [Toc]    [Back]

     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)
                        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]         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} characters,
 or an entire path name exceeded {PATH_MAX} characters.


     [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
                        denied.

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

SEE ALSO    [Toc]    [Back]

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

HISTORY    [Toc]    [Back]

     The connect() function call appeared in 4.2BSD.

BSD                            October 16, 2001                            BSD