rust/src/test/run-pass/packed-struct-layout.rs
2015-06-13 14:55:55 +03:00

38 lines
982 B
Rust

// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use std::mem;
#[repr(packed)]
struct S4 {
a: u8,
b: [u8; 3],
}
#[repr(packed)]
struct S5 {
a: u8,
b: u32
}
pub fn main() {
unsafe {
let s4 = S4 { a: 1, b: [2,3,4] };
let transd : [u8; 4] = mem::transmute(s4);
assert_eq!(transd, [1, 2, 3, 4]);
let s5 = S5 { a: 1, b: 0xff_00_00_ff };
let transd : [u8; 5] = mem::transmute(s5);
// Don't worry about endianness, the u32 is palindromic.
assert_eq!(transd, [1, 0xff, 0, 0, 0xff]);
}
}