initial import

best-practices/error-handling-3/main.go

@@ -0,0 +1,48 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"os"
+)
+
+func NewWriter(w io.Writer) *writer {
+	return &writer{w, nil}
+}
+
+type writer struct {
+	w   io.Writer
+	err error
+}
+
+func (w *writer) write(text string) {
+	if w.err != nil {
+		return
+	}
+	_, w.err = fmt.Fprintln(w.w, text)
+}
+
+func (w *writer) Err() error {
+	return w.err
+}
+
+func main() {
+
+	f, err := os.OpenFile("test.txt", os.O_WRONLY, os.ModePerm)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer f.Close()
+
+	w := NewWriter(f)
+
+	w.write("Hello world 3")
+	w.write("Hello world 3")
+
+	if err = w.Err(); err != nil {
+		log.Fatal(err)
+	}
+	fmt.Println(f)
+
+}

best-practices/error-handling-3/test.txt

@@ -0,0 +1,2 @@
+Hello world 3
+Hello world 3