the go blog defer panic recover
package main
import "fmt"
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)
}
4.17
6
func a() {
i := 0
defer fmt.Println(i)
i++
return
}
Thank you!
6
4.17
(6 Votes)
0
4.5
2
Calling g.
Printing in g 0
Printing in g 1
Printing in g 2
Printing in g 3
Panicking!
Defer in g 3
Defer in g 2
Defer in g 1
Defer in g 0
panic: 4
panic PC=0x2a9cd8
[stack trace omitted]
Thank you!
2
4.5
(2 Votes)
0
4.18
9
Calling g.
Printing in g 0
Printing in g 1
Printing in g 2
Printing in g 3
Panicking!
Defer in g 3
Defer in g 2
Defer in g 1
Defer in g 0
Recovered in f 4
Returned normally from f.
Thank you!
9
4.18
(11 Votes)
0
4.2
5
mu.Lock()
defer mu.Unlock()
Thank you!
5
4.2
(5 Votes)
0
4.8
2
func b() {
for i := 0; i < 4; i++ {
defer fmt.Print(i)
}
}
Thank you!
2
4.8
(5 Votes)
0
3.67
9
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)
}
Thank you!
9
3.67
(9 Votes)
0
4.5
4
func c() (i int) {
defer func() { i++ }()
return 1
}
Thank you!
4
4.5
(4 Votes)
0
4.67
3
func CopyFile(dstName, srcName string) (written int64, err error) {
src, err := os.Open(srcName)
if err != nil {
return
}
dst, err := os.Create(dstName)
if err != nil {
return
}
written, err = io.Copy(dst, src)
dst.Close()
src.Close()
return
}
Thank you!
3
4.67
(3 Votes)
0
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