NAME

connect – initiate a connection on a socket

SYNOPSIS

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

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

DESCRIPTION

The parameter s is a socket. If it is of type SOCK_DGRAM, connect() specifies the peer with which the socket is to be associated; this address is the address to which datagrams are to be sent if a receiver is not explicitly designated; it is the only address from which datagrams are to be received. If the socket s is of type SOCK_STREAM, connect() attempts to make a connection to another socket. The other socket is specified by name. name is an address in the communication space of the socket. Each communication space interprets the name parameter in its own way. If s is not bound, then it will be bound to an address selected by the underlying transport provider. 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 a null address.

RETURN VALUES

If the connection or binding succeeds, then 0 is returned. Otherwise a -1 is returned and sets errno to indicate the error.

ERRORS

This function is a member of Unison’s IOLIB family of functions. IOLIB is implemented as a message passing and generalized interface layer. Each Unison I/O server is responsible for its own error reporting.

For an exact list of error codes returned by a particular server, refer to that server’s documentation in the Unison Programmer’s Guide for each specific platform.

Servers may implement these errors codes in response to this function.

The call fails if:

EACCES

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

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() the socket descriptor, and issue another socket() call to obtain a new descriptor before attempting another connect() call.

EINPROGRESS

The socket is non-blocking and the connection cannot be completed immediately. It is possible to select for completion by selecting the socket for writing. However, this is only possible if the socket STREAMS module is the topmost module on the protocol stack with a write service procedure. This will be the normal case.

EINVAL

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

EIO

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

EISCONN

The socket is already connected.

ENETUNREACH

The network is not reachable from this host.

ENOENT

A component of the path prefix of the pathname in name or the socket referred to by the pathname in name does not exist.

SEE ALSO

accept(), bind(), getsockname(), socket(), select(), send()