如何检查两个变量是否指向内存中的同一对象? [英] How to check if two variables point to the same object in memory?

问题描述

例如:

struct Foo<'a> { bar: &'a str }

fn main() {
    let foo_instance = Foo { bar: "bar" };
    let some_vector: Vec<&Foo> = vec![&foo_instance];

    assert!(*some_vector[0] == foo_instance);
}

1. 我想检查foo_instance是否引用与*some_vector[0]相同的实例，但是我不能这样做...

1. I want to check if foo_instance references the same instance as *some_vector[0], but I can't do this ...

我不想知道两个实例是否相等；我想检查变量是否指向内存中的同一实例

I don't want to know if the two instances are equal; I want to check if the variables point to the same instance in the memory

有可能这样做吗?

推荐答案

有函数 ptr::eq :

use std::ptr;

struct Foo<'a> {
    bar: &'a str,
}

fn main() {
    let foo_instance = Foo { bar: "bar" };
    let some_vector: Vec<&Foo> = vec![&foo_instance];

    assert!(ptr::eq(some_vector[0], &foo_instance));
}

在Rust 1.17.0中将其稳定之前，可以将其强制转换为*const T:

Before this was stabilized in Rust 1.17.0, you could perform a cast to *const T:

assert!(some_vector[0] as *const Foo == &foo_instance as *const Foo);

它将检查引用是否指向内存中的同一位置.

It will check if the references point to the same place in the memory.

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