Upgrade error module

13-Errors/02-Error/17162-7Learn/.vscode/launch.json

@@ -0,0 +1,15 @@
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Launch Package",
+            "type": "go",
+            "request": "launch",
+            "mode": "auto",
+            "program": "${workspaceFolder}/main.go"
+        }
+    ]
+}

13-Errors/02-Error/17162-7Learn/go.mod

@@ -0,0 +1,3 @@
+module ErrorExample
+
+go 1.20

13-Errors/02-Error/17162-7Learn/main.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+)
+
+type IOError struct {
+	FileName string
+	Message  string
+	Err      error
+}
+
+func (error *IOError) Unwrap() error {
+	return error.Err
+}
+
+func (error IOError) Error() string {
+	return fmt.Sprintf("IO error occurred: FileName: %s Message: %s Detail: %s", error.FileName, error.Message, error.Err.Error())
+}
+
+func CopyFile(srcName, dstName string) error {
+	src, err := os.Open(srcName)
+	if err != nil {
+		return &IOError{FileName: srcName, Message: "during copy file could not open source file", Err: err}
+	}
+	//defer src.Close()
+	dst, err := os.Create(dstName)
+	if err != nil {
+		return &IOError{FileName: srcName, Message: "during copy file could not create destination file", Err: err}
+	}
+	dst.Close()
+	_, err = io.Copy(dst, src)
+	fmt.Printf("io error: %s\n", err)
+	var ioErr IOError = IOError{}
+	if errors.Is(err,ioErr){
+		fmt.Printf("cast error: %s\n", ioErr)
+	}
+	if err != nil {
+		return &IOError{FileName: srcName, Message: "during copy file could not copy", Err: err}
+	}
+	return nil
+}
+func main() {
+	err := CopyFile("src.txt", "dst.txt")
+	fmt.Printf("%s\n", err)
+	fmt.Printf("Unwrap Error: %s", errors.Unwrap(err))
+
+	if err != nil {
+		fmt.Printf("Error: %s\n", err)
+	}
+}