Imported Upstream version 1upstream/1

1 files changed, 58 insertions, 0 deletions

diff --git a/doc/progs/defer2.go b/doc/progs/defer2.go
new file mode 100644
index 000000000..cad66b070
--- /dev/null
+++ b/doc/progs/defer2.go
@@ -0,0 +1,58 @@
+// 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, and 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