/ server.go /
package main

import (
"fmt"
"net"
"os"
)

func checkError(err error) {
if err != nil {
fmt.Println("Error: %s", err.Error())
os.Exit(1)
}
}

func recvUDPMsg(conn *net.UDPConn) {
var buf [20]byte

    n, raddr, err := conn.ReadFromUDP(buf[0:])
    if err != nil {
            return
    }

    fmt.Println("msg is ", string(buf[0:n]))

    //WriteToUDP
    //func (c *UDPConn) WriteToUDP(b []byte, addr *UDPAddr) (int, error)
    _, err = conn.WriteToUDP([]byte("nice to see u"), raddr)
    checkError(err)

}

func main() {
udp_addr, err := net.ResolveUDPAddr("udp", ":9098")
checkError(err)

    conn, err := net.ListenUDP("udp", udp_addr)
    defer conn.Close()
    checkError(err)

    //go recvUDPMsg(conn)
    for {
            recvUDPMsg(conn)
    }

}

/ client.go /
package main

import (
"fmt"
"net"
"os"
// "io"
)

func main() {
conn, err := net.Dial("udp", "127.0.0.1:9098")
defer conn.Close()
if err != nil {
os.Exit(1)
}

    conn.Write([]byte("Hello world!"))

    fmt.Println("send msg")

    var msg [20]byte
    conn.Read(msg[0:])

    fmt.Println("msg is", string(msg[0:10]))

}