Rust手动内存管理 [英] Rust manual memory management

问题描述

当我开始学习C时，我实现了常见的数据结构，例如列表，地图和树.当请求时，我使用malloc，calloc，realloc和free来手动管理内存.我使用new和delete对C ++做了同样的事情.

When I began learning C, I implemented common data structures such as lists, maps and trees. I used malloc, calloc, realloc and free to manage the memory manually when requested. I did the same thing with C++, using new and delete.

现在来了Rust.至少在稳定版本中，Rust似乎没有提供与C或C ++相对应的任何函数或运算符.

Now comes Rust. It seems like Rust doesn't offer any functions or operators which correspond to the ones of C or C++, at least in the stable release.

是 Heap 结构和 ptr 模块(标记为experimental)，用于此类东西吗?

Are the Heap structure and the ptr module (marked with experimental) the ones to look at for this kind of thing?

我知道这些数据结构已经在语言中了.这是为了学习.

I know that these data structures are already in the language. It's for the sake of learning.

推荐答案

直接访问Rust中的内存分配器是非常不寻常的.通常，您希望对单个对象使用智能指针构造函数(Box::new，Rc::new，Arc::new)，如果要基于堆的数组，则只需使用Vec或Box<[T]>.

It's very unusual to directly access the memory allocator in Rust. You generally want to use the smart pointer constructors (Box::new, Rc::new, Arc::new) for single objects and just use Vec or Box<[T]> if you want a heap-based array.

如果您确实想分配内存并获取指向它的原始指针，则可以查看Rc的实现. (不是Box.Box是神奇的.)为了获取其后备内存，它实际上创建了Box，然后使用其into_raw_non_null函数来获取原始指针.对于销毁，它使用分配器API，但也可以使用Box::from_raw然后使用drop.

If you really want to allocate memory and get a raw pointer to it, you can look at the implementation of Rc. (Not Box. Box is magical.) To get its backing memory, it actually creates a Box and then uses its into_raw_non_null function to get the raw pointer out. For destroying, it uses the allocator API, but could alternatively use Box::from_raw and then drop that.

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