How to allocate arrays on the heap in Rust 1.0? -

there question related rust 0.13 , syntax seems have changed. current documentation understood creating array on heap this:

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

but when run program following error:

thread '<main>' has overflowed stack

what doing wrong?

the problem array being passed box::new function argument, means has created first, means has created on stack.

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

the solution not use fixed-size array @ all, vec. simplest way can think of make vec of 8 million 10.0 this:

fn main() {     const size: usize = 1024 * 1024;     let v = vec![10.0; size]; }

or, if reason you'd rather use iterators:

use std::iter::repeat;  fn main() {     const size: usize = 1024 * 1024;     let v: vec<_> = repeat(10.0).take(size).collect(); }

this should perform single heap allocation.

edit: note can subsequently take vec , turn box<[_]> using into_boxed_slice method.

Lix