NAME    [Toc]    [Back]

     connect - initiate a connection on a socket

SYNOPSIS    [Toc]    [Back]

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

     [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 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 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}
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.

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

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

     [EPROTOTYPE]  The file described by name is of  a  different
type than s.
                   E.g.,  s  may  be  of type SOCK_STREAM whereas
name may refer
                   to a socket of type SOCK_DGRAM.

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.

OpenBSD      3.6                        February     15,     1999