dreljie602951
2017-10-28 07:55
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在Go中处理悬空指针

I have been reading Rust and Go in parallel and I see subtle differences in how both these languages deal with dangling pointers and the problems it causes. For example, here is a version in Rust:

fn main() {
    let reference_to_nothing = dangle();
}

fn dangle() -> &String {
    let s = String::from("hello");

    &s
}

The above would error out saying that in the function dangle, s goes out of scope and I cannot return a reference to it! But in Go, this seems to be sort of allowed?

How is such a thing handled in Go? Is it easy to create dangling pointers in Go? If so what measures do I have to control them?

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  • dqan70724 2017-10-28 08:16
    已采纳

    In Go, dangling pointers are not a thing, due to the way how escape analysis works. Suppose you have a code like this:

    func CreateUser(name string) *User {
        return &User{Name: name}
    }
    

    The compiler will understand that because the pointer can be accessed after the function exits, the structure should be allocated on heap. As Effective Go says:

    Note that, unlike in C, it's perfectly OK to return the address of a local variable; the storage associated with the variable survives after the function returns.

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