Go中沒有原生的禁止拷貝的方式，所以如果有的結構體，你希望使用者無法拷貝，只能指針傳遞保證全局唯一的話，可以這么干，定義 一個結構體叫 noCopy ，要實現 sync.Locker 這個接口
// noCopy may be embedded into structs which must not be copied // after the first use. // // See https://golang.org/issues/8005#issuecomment-190753527 // for details. type noCopy struct{} // Lock is a no-op used by -copylocks checker from `go vet`. func (*noCopy) Lock() {} func (*noCopy) UnLock() {}
然后把 noCopy 嵌到你自定義的結構體里，然后 go vet 就可以幫我們進行檢查了。舉個例子：
package main import ( "fmt" ) type noCopy struct{} func (*noCopy) Lock() {} func (*noCopy) Unlock() {} type Demo struct { noCopy noCopy } func Copy(d Demo) { CopyTwice(d) } func CopyTwice(d Demo) {} func main() { d := Demo{} fmt.Printf("%+v", d) Copy(d) fmt.Printf("%+v", d) }
執行一下：
$ go vet main.go # command-line-arguments ./main.go:16: Copy passes lock by value: main.Demo contains main.noCopy ./main.go:17: call of CopyTwice copies lock value: main.Demo contains main.noCopy ./main.go:19: CopyTwice passes lock by value: main.Demo contains main.noCopy ./main.go:23: call of fmt.Printf copies lock value: main.Demo contains main.noCopy ./main.go:25: call of Copy copies lock value: main.Demo contains main.noCopy ./main.go:27: call of fmt.Printf copies lock value: main.Demo contains main.noCopy