Open System Services System Calls Reference Manual (G06.25+, H06.03+)

System Functions (a - d) connect(2)

NAME

connect - Connects a socket

LIBRARY

G-series native OSS processes: system library

H-series OSS processes: implicit libraries

SYNOPSIS

#include <sys/socket.h>

int connect(

int socket,

const struct sockaddr *address,

size_t address_len

);

PARAMETERS

socket Speciﬁes the ﬁle descriptor for the socket.

address Points to a sockaddr structure that contains the address of the peer socket. The

length and format of the address depend on the address family of the socket.

For AF_INET sockets, a pointer to the address structure sockaddr_in must be

cast as a struct sockaddr.ForAF_INET6 sockets, a pointer to the address

structure sockaddr_in6 must be cast as a struct sockaddr.ForAF_UNIX sock-

ets, a pointer to the address structure sockaddr_un must be cast as a struct

sockaddr.

address_len Speciﬁes the length of the sockaddr structure pointed to by the address parame-

ter.

DESCRIPTION

The connect() function requests that a connection be made on a socket.

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

sockets:

• If the initiating socket is not connection-oriented (has the type SOCK_DGRAM), then

the connect() function sets the peer address but no connection is made. The peer

address identiﬁes the socket where all datagrams are sent by subsequent calls to the

send() function, and limits the remote sender for subsequent recv() function calls.

Datagram sockets can use the connect() function multiple times to communicate with

different peers.

If the socket is a datagram socket and address is a null address for the protocol, the

address for the peer socket is reset.

• If the initiating socket is connection-oriented (has the type SOCK_STREAM), then the

connect() function attempts to make a connection to the socket speciﬁed by the address

parameter. Sockets of type SOCK_STREAM can successfully connect only once.

When a connection cannot be created immediately and O_NONBLOCK is not set for the ﬁle

descriptor of the socket, the connect() call blocks until one of the following occurs:

• A connection is established

• A timeout occurs

• A signal is caught

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