connect(2) - NetBSD Manual Pages

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CONNECT(2)                NetBSD Programmer's Manual                CONNECT(2)


NAME

     connect - initiate a connection on a socket


LIBRARY

     Standard C Library (libc, -lc)


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 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 successful-
     ly connect() only once; datagram sockets may use connect() multiple times
     to change their association.  Datagram sockets may dissolve the associa-
     tion 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 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 opera-
                   tion 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 fail-
                   ure.

     [EALREADY]    The socket is non-blocking and a previous connection at-
                   tempt 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

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


HISTORY

     The connect() function call appeared in 4.2BSD.

NetBSD 1.5.3_RC1                 June 4, 1993                                2