1 files changed, 35 insertions, 0 deletions
diff --git a/src/flag/example_textvar_test.go b/src/flag/example_textvar_test.go
new file mode 100644
index 0000000..8b8cbf6
--- /dev/null
+++ b/src/flag/example_textvar_test.go
@@ -0,0 +1,35 @@
+// Copyright 2022 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 flag_test
+
+import (
+	"flag"
+	"fmt"
+	"net"
+	"os"
+)
+
+func ExampleTextVar() {
+	fs := flag.NewFlagSet("ExampleTextVar", flag.ContinueOnError)
+	fs.SetOutput(os.Stdout)
+	var ip net.IP
+	fs.TextVar(&ip, "ip", net.IPv4(192, 168, 0, 100), "`IP address` to parse")
+	fs.Parse([]string{"-ip", "127.0.0.1"})
+	fmt.Printf("{ip: %v}\n\n", ip)
+
+	// 256 is not a valid IPv4 component
+	ip = nil
+	fs.Parse([]string{"-ip", "256.0.0.1"})
+	fmt.Printf("{ip: %v}\n\n", ip)
+
+	// Output:
+	// {ip: 127.0.0.1}
+	//
+	// invalid value "256.0.0.1" for flag -ip: invalid IP address: 256.0.0.1
+	// Usage of ExampleTextVar:
+	//   -ip IP address
+	//     	IP address to parse (default 192.168.0.100)
+	// {ip: <nil>}
+}