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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package net_test
import (
"context"
"fmt"
"io"
"log"
"net"
"time"
)
func ExampleListener() {
// Listen on TCP port 2000 on all available unicast and
// anycast IP addresses of the local system.
l, err := net.Listen("tcp", ":2000")
if err != nil {
log.Fatal(err)
}
defer l.Close()
for {
// Wait for a connection.
conn, err := l.Accept()
if err != nil {
log.Fatal(err)
}
// Handle the connection in a new goroutine.
// The loop then returns to accepting, so that
// multiple connections may be served concurrently.
go func(c net.Conn) {
// Echo all incoming data.
io.Copy(c, c)
// Shut down the connection.
c.Close()
}(conn)
}
}
func ExampleDialer() {
var d net.Dialer
ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
defer cancel()
conn, err := d.DialContext(ctx, "tcp", "localhost:12345")
if err != nil {
log.Fatalf("Failed to dial: %v", err)
}
defer conn.Close()
if _, err := conn.Write([]byte("Hello, World!")); err != nil {
log.Fatal(err)
}
}
func ExampleIPv4() {
fmt.Println(net.IPv4(8, 8, 8, 8))
// Output:
// 8.8.8.8
}
func ExampleParseCIDR() {
ipv4Addr, ipv4Net, err := net.ParseCIDR("192.0.2.1/24")
if err != nil {
log.Fatal(err)
}
fmt.Println(ipv4Addr)
fmt.Println(ipv4Net)
ipv6Addr, ipv6Net, err := net.ParseCIDR("2001:db8:a0b:12f0::1/32")
if err != nil {
log.Fatal(err)
}
fmt.Println(ipv6Addr)
fmt.Println(ipv6Net)
// Output:
// 192.0.2.1
// 192.0.2.0/24
// 2001:db8:a0b:12f0::1
// 2001:db8::/32
}
func ExampleParseIP() {
fmt.Println(net.ParseIP("192.0.2.1"))
fmt.Println(net.ParseIP("2001:db8::68"))
fmt.Println(net.ParseIP("192.0.2"))
// Output:
// 192.0.2.1
// 2001:db8::68
// <nil>
}
func ExampleIP_DefaultMask() {
ip := net.ParseIP("192.0.2.1")
fmt.Println(ip.DefaultMask())
// Output:
// ffffff00
}
func ExampleIP_Mask() {
ipv4Addr := net.ParseIP("192.0.2.1")
// This mask corresponds to a /24 subnet for IPv4.
ipv4Mask := net.CIDRMask(24, 32)
fmt.Println(ipv4Addr.Mask(ipv4Mask))
ipv6Addr := net.ParseIP("2001:db8:a0b:12f0::1")
// This mask corresponds to a /32 subnet for IPv6.
ipv6Mask := net.CIDRMask(32, 128)
fmt.Println(ipv6Addr.Mask(ipv6Mask))
// Output:
// 192.0.2.0
// 2001:db8::
}
func ExampleCIDRMask() {
// This mask corresponds to a /31 subnet for IPv4.
fmt.Println(net.CIDRMask(31, 32))
// This mask corresponds to a /64 subnet for IPv6.
fmt.Println(net.CIDRMask(64, 128))
// Output:
// fffffffe
// ffffffffffffffff0000000000000000
}
func ExampleIPv4Mask() {
fmt.Println(net.IPv4Mask(255, 255, 255, 0))
// Output:
// ffffff00
}
func ExampleUDPConn_WriteTo() {
// Unlike Dial, ListenPacket creates a connection without any
// association with peers.
conn, err := net.ListenPacket("udp", ":0")
if err != nil {
log.Fatal(err)
}
defer conn.Close()
dst, err := net.ResolveUDPAddr("udp", "192.0.2.1:2000")
if err != nil {
log.Fatal(err)
}
// The connection can write data to the desired address.
_, err = conn.WriteTo([]byte("data"), dst)
if err != nil {
log.Fatal(err)
}
}
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