在Nim中创建对数组的引用 [英] create a reference to an array in Nim

问题描述

var b: array[5, int]

type
    ArrRef = ref array[5, int]

var c : ArrRef
echo repr(c) # nil
c = addr b # doesn't compile, says type is Array constructor, expected reference

在Nim中，如何将引用传递给数组而不是按值传递?到目前为止，请参阅上面的代码.

In Nim, how can I pass references to arrays instead of passing by value? See the above code for what I have so far.

推荐答案

在Nim中，ref在堆上，必须使用new进行分配.您不能仅将堆栈数组用作ref，因为这是不安全的:当数组从堆栈中消失时，ref指向某个错误的内存.相反，您有两个选择:您可以改用不安全的ptr.除ref外，它们不是垃圾收集的，可用于不安全的物品.或者，您可以直接将b设置为ref array.

In Nim refs are on the heap and have to be allocated with new. You can't just use a stack array as a ref because that would be unsafe: When the array disappears from the stack, the ref points to some wrong memory. Instead you have two choices: You can use unsafe ptrs instead. Other than refs, they are not garbage collected and can be used for unsafe stuff. Alternatively you can make b a ref array directly.

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