UDP(3X) UDP(3X)
NAME
udp_connect, udp_listen, udp_datagram - udp networking
functions
SYNOPSIS
#include <sys/inet/udp_user.h>
int udp_connect(sport, dhost, dport)
in_addr dhost;
udp_port sport, dport;
int udp_listen(sport, reply)
udp_port sport;
struct udpreply *reply;
int udp_datagram(sport)
udp_port sport;
DESCRIPTION
These routines are loaded by the -lin option of ld(1).
UDP (universal datagram protocol) is a protocol layered upon
IP (internet protocol). It provides datagram service
between end points called sockets. A socket address is com-
posed of the internet address of its host and the port num-
ber to which the socket is bound.
Udp_connect returns the file descriptor of a UDP socket
bound to port sport. Each read(2) from this file descriptor
will only accept datagrams from the UDP socket at host
dhost, port dport; a write on this file descriptor will be
sent to that socket.
Udp_listen returns the file descriptor of a UDP socket bound
to port sport and waits for a datagram to be sent to that
port. Once a message has been received from another socket,
all writes will go to that socket and reads will only accept
data from that socket.
Udp_datagram returns the file descriptor of a UDP socket
bound to port sport. Messages written to the file descriptor
must start with a struct udpaddr which contains the destina-
tion of the message.
struct udpaddr {
in_addr host;
int port;
};
Messages read from the file descriptor also start with a
UDP(3X) UDP(3X)
struct udpaddr and contain the address of the source socket.
FILES
the socket devices
SEE ALSO
internet(3), tcp(3)
DIAGNOSTICS
All these routines returns -1 on failure.