#[repr(C)] #[derive(Copy, Clone)] struct Foo { a: u64, b: u64, c: u64, } fn main() { const LENGTH: usize = 10; let mut v: [u64; LENGTH] = [0; LENGTH]; for idx in 0..LENGTH { assert_eq!(v[idx], 0); } unsafe { let p = v.as_mut_ptr(); ::std::ptr::write_bytes(p, 0xab, LENGTH); } for idx in 0..LENGTH { assert_eq!(v[idx], 0xabababababababab); } // ----- let mut w: [Foo; LENGTH] = [Foo { a: 0, b: 0, c: 0 }; LENGTH]; for idx in 0..LENGTH { assert_eq!(w[idx].a, 0); assert_eq!(w[idx].b, 0); assert_eq!(w[idx].c, 0); } unsafe { let p = w.as_mut_ptr(); ::std::ptr::write_bytes(p, 0xcd, LENGTH); } for idx in 0..LENGTH { assert_eq!(w[idx].a, 0xcdcdcdcdcdcdcdcd); assert_eq!(w[idx].b, 0xcdcdcdcdcdcdcdcd); assert_eq!(w[idx].c, 0xcdcdcdcdcdcdcdcd); } }