term% cat index.txt UDP(3) Library Functions Manual UDP(3)
NAME
udp_connect, udp_listen, udp_datagram - udp operations
SYNOPSIS
#include <sys/inet/udp_user.h>
udp_connect(sport, dhost, dport)
in_addr dhost;
udp_port sport, dport;
udp_listen(sport, reply)
udp_port sport;
struct udpreply *reply;
udp_datagram(sport)
udp_port sport;
DESCRIPTION
These routines are loaded by the -lin option of ld(1).
UDP is one of the many protocols which are layered upon IP (internet
protocol). It provides datagram service between end points called
sockets. A socket address is composed of the internet address of its
host and the port number to which the socket is bound.
Udp_connect returns the fd of a UDP socket bound to port sport. All
writes(2) performed on this fd will be sent to the UDP socket at host
dhost, port dport and reads(2) from this fd will only accept datagrams
from that socket. Udp_connect returns -1 on failure.
Udp_listen returns the fd of a UDP socket bound to port sport and waits
for a datagram to be sent to that port. Once a message has been re‐
ceived from another socket, all writes(2) will go to that socket and
reads(2) will only accept data from that socket.
Udp_datagram returns the fd of a UDP socket bound to port sport. All
messages written to the socket must start with a struct udpaddr which
contains the destination of the message.
struct udpaddr { /* from udp_user.h */
in_addr host;
int port;
};
All messages read from the socket also start with a struct udpaddr and
contain the address of the source socket.
FILES
/dev/udp* the socket devices
SEE ALSO
internet(3), tcp(3)
UDP(3)