6e8ff99958
As of RFC 18, struct layout is undefined. Opting into a C-compatible struct layout is now down with #[repr(C)]. For consistency, specifying a packed layout is now also down with #[repr(packed)]. Both can be specified. To fix errors caused by this, just add #[repr(C)] to the structs, and change #[packed] to #[repr(packed)] Closes #14309 [breaking-change]
37 lines
988 B
Rust
37 lines
988 B
Rust
// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use std::mem;
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#[repr(packed)]
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struct S4 {
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a: u8,
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b: [u8, .. 3],
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}
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#[repr(packed)]
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struct S5 {
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a: u8,
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b: u32
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}
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pub fn main() {
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unsafe {
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let s4 = S4 { a: 1, b: [2,3,4] };
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let transd : [u8, .. 4] = mem::transmute(s4);
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assert!(transd == [1, 2, 3, 4]);
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let s5 = S5 { a: 1, b: 0xff_00_00_ff };
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let transd : [u8, .. 5] = mem::transmute(s5);
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// Don't worry about endianness, the u32 is palindromic.
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assert!(transd == [1, 0xff, 0, 0, 0xff]);
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}
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}
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