doc: add Defer, Panic, and Recover article
Originally published on The Go Programming Language Blog, August 4 2010.
http://blog.golang.org/2010/08/defer-panic-and-recover.html
Update #2547
R=golang-dev, r, r
CC=golang-dev
https://golang.org/cl/5479053
diff --git a/doc/progs/defer2.go b/doc/progs/defer2.go
new file mode 100644
index 0000000..be6791d
--- /dev/null
+++ b/doc/progs/defer2.go
@@ -0,0 +1,56 @@
+// Copyright 2011 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.
+
+// This file contains the code snippets included in "Defer, Panic, an Recover."
+
+package main
+
+import "fmt"
+import "io" // OMIT
+import "os" // OMIT
+
+func main() {
+ f()
+ fmt.Println("Returned normally from f.")
+}
+
+func f() {
+ defer func() {
+ if r := recover(); r != nil {
+ fmt.Println("Recovered in f", r)
+ }
+ }()
+ fmt.Println("Calling g.")
+ g(0)
+ fmt.Println("Returned normally from g.")
+}
+
+func g(i int) {
+ if i > 3 {
+ fmt.Println("Panicking!")
+ panic(fmt.Sprintf("%v", i))
+ }
+ defer fmt.Println("Defer in g", i)
+ fmt.Println("Printing in g", i)
+ g(i + 1)
+}
+// STOP OMIT
+
+// Revised version.
+func CopyFile(dstName, srcName string) (written int64, err error) {
+ src, err := os.Open(srcName)
+ if err != nil {
+ return
+ }
+ defer src.Close()
+
+ dst, err := os.Create(dstName)
+ if err != nil {
+ return
+ }
+ defer dst.Close()
+
+ return io.Copy(dst, src)
+}
+// STOP OMIT
