CONNECT(2)

NAME
connect - initiate a connection on a socket

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

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

DESCRIPTION

The parameter s is a socket. If it is of type SOCK_DGRAM, then 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 it is of type SOCK_STREAM, then 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

connect() returns:

0   on success.

-1  on failure and sets errno to indicate the error.

ERRORS

The call fails if:

EADDRINUSE
    The address is already in use.

EADDRNOTAVAIL
    The specified address is not available on the remote machine.

EAFNOSUPPORT
    Addresses in the specified address family cannot be used with this socket.

EALREADY
    The socket is non-blocking and a previous connection attempt has not yet been completed.

EBADF
    s is not a valid descriptor.

ECONNREFUSED
    The attempt to connect was forcefully rejected. The calling program should close(2V) the socket descriptor, and issue another socket(2) call to obtain a new descriptor before attempting another connect(2) call.

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.

EINTR
    The connection attempt was interrupted before any data arrived by the delivery of a signal.

EINVAL
    namelen is not the size of a valid address for the specified address family.

EISCONN
    The socket is already connected.

ENETUNREACH
    The network is not reachable from this host.

ENOTSOCK
    s is a descriptor for a file, not a socket.

ETIMEDOUT
    Connection establishment timed out without establishing a connection.

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.

EACCES
    Search permission is denied for a component of the path prefix of the path name in name.

ELOOP
    Too many symbolic links were encountered in translating the path name in name.

EIO An I/O error occurred while reading from or writing to the file system.

ENAMETOOLONG
    The length of the path argument exceeds {PATH_MAX}.

    A pathname component is longer than {NAME_MAX} (see sysconf(2V)) while {_POSIX_NO_TRUNC} is in effect (see pathconf(2V)).

ENOENT
    A component of the path prefix of the path name in name does not exist.

    The socket referred to by the path name in name does not exist.

ENOTDIR
    A component of the path prefix of the path name in name is not a directory.

ENOTSOCK
    The file referred to by name is not a socket.

EPROTOTYPE
    The file referred to by name is a socket of a type other than the type of s (e.g., s is a SOCK_DGRAM socket, while name refers to a SOCK_STREAM socket).

SEE ALSO
accept(2), close(2V), connect(2), getsockname(2), select(2), socket(2)