如何在堆上分配阵列位于Rust 1.0（测试版）？ [英] How to allocate arrays on the heap in Rust 1.0 (beta)?

问题描述

有已经是<一个href=\"http://stackoverflow.com/questions/26637158/stack-overflow-with-large-fixed-size-array-in-rust-0-13\">question为此但是相关生锈0.13和语法似乎已经改变（？）。从目前文档我了解，创建的一个数组堆将是这样的：

There is already a question for this but related to Rust 0.13 and the syntax seems to have changed (?). From the current documentation I understood that creating an array on the heap would be something like this:

fn main() {
    const SIZE: usize = 1024 * 1024;
    Box::new([10.0; SIZE]);
}

但是，当我运行这个程序，我得到了以下错误：

But when I run this program I get the following error:

thread '<main>' has overflowed its stack

我在做什么错了？

What am I doing wrong?

推荐答案

的问题是，该数组被传递到箱::新函数作为参数，这意味着它必须创建的第一个的，这意味着它已经被创建的堆栈的

The problem is that the array is being passed to the Box::new function as an argument, which means it has to be created first, which means it has to be created on the stack.

你问编译器创建的 8兆字节的堆栈上的数据：这是什么四溢它

You're asking the compiler to create 8 megabytes of data on the stack: that's what's overflowing it.

解决的办法是不使用一个固定大小的数组可言，但 VEC 。我能想到的最简单的方法，使一个 VEC 800万 10.0 是这样的：

The solution is to not use a fixed-size array at all, but a Vec. The simplest way I can think of to make a Vec of 8 million 10.0 is this:

use std::iter::repeat;

fn main() {
    const SIZE: usize = 1024 * 1024;
    let v: Vec<_> = repeat(10.0).take(SIZE).collect();
}

此的应的只能执行单一的堆分配。

This should only perform a single heap allocation.

修改：另外请注意，随后就可以采取 VEC 键，把它变成一个盒＆LT; _] ＆GT; 通过使用<$c$c>into_boxed_slice方法。

Edit: Also note that you can subsequently take a Vec and turn it into a Box<[_]> by using the into_boxed_slice method.

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