OSF

NAME

connect −  Connects two sockets

SYNOPSIS

#include <sys/types.h> #include <sys/socket.h> int connect (
int socket,
struct sockaddr ∗address,
int address_len );

PARAMETERS

socketSpecifies the unique name of the socket. 

addressPoints to a sockaddr structure, the format of which is determined by the domain and by the behavior requested for the socket.  The sockaddr structure is an overlay for a sockaddr_in, sockaddr_un, or sockaddr_ns structure, depending on which of the supported address families is active.  If the compile-time option _SOCKADDR_LEN is defined before the sys/socket.h header file is included, the sockaddr structure takes 4.4BSD behavior, with a field for specifying the length of the socket address.  Otherwise, the default 4.3BSD sockaddr structure is used, with the length of the socket address assumed to be 14 bytes or less.  If _SOCKADDR_LEN is defined, the 4.3BSD sockaddr structure is defined with the name osockaddr. 

address_lenSpecifies the length of the sockaddr structure pointed to by the address parameter. 

DESCRIPTION

The connect() function requests a connection between two sockets.  The kernel sets up the communications links between the sockets; both sockets must use the same address format andprotocol. 

The connect() function performs a different action for each of the following types of initiating sockets:

       •If the initiating socket is SOCK_DGRAM, then the connect() function establishes the peer address.  The peer address identifies the socket where all datagrams are sent on subsequent send() functions.  No connections are made by this connect function. 

       •If the initiating socket is SOCK_STREAM, then the connect() function attempts to make a connection to the socket specified by the address parameter.  Each communication space interprets the address parameter differently. 

RETURN VALUES

Upon successful completion, the connect() function returns a value of 0 (zero).  Otherwise, a value of -1 is returned and errno is set to indicate the error. 

ERRORS

If the connect() function fails, errno may be set to one of the following values:

[EBADF]The socket parameter is not valid. 

[ENOTSOCK]
The socket parameter refers to a file, not a socket. 

[EADDRNOTAVAIL]
The specified address is not available from the local machine.

[EAFNOSUPPORT]
The addresses in the specified address family cannot be used with this socket.

[EISCONN]The socket is already connected. 

[ETIMEDOUT]
The establishment of a connection timed out before a connection was made.

[ECONNREFUSED]
The attempt to connect was rejected.

[ENETUNREACH]
No route to the network or host is present.

[EADDRINUSE]
The specified address is already in use.

[EFAULT]The address parameter is not in a readable part of the user address space. 

[EWOULDBLOCK]
The socket is marked nonblocking, so the connection cannot be immediately completed.  The application program can select the socket for writing during the connection process.

RELATED INFORMATION

Functions: accept(2), bind(2), socket(2), getsockname(2), select(2), send(2)