rust/src/test/compile-fail/packed-struct-transmute.rs
Corey Richardson 6e8ff99958 librustc: handle repr on structs, require it for ffi, unify with packed
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]
2014-08-20 21:02:23 -04:00

40 lines
971 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.
// This assumes the packed and non-packed structs are different sizes.
// the error points to the start of the file, not the line with the
// transmute
// error-pattern: transmute called on types with different size
extern crate debug;
use std::mem;
#[repr(packed)]
struct Foo {
bar: u8,
baz: uint
}
struct Oof {
rab: u8,
zab: uint
}
fn main() {
let foo = Foo { bar: 1, baz: 10 };
unsafe {
let oof: Oof = mem::transmute(foo);
println!("{:?}", oof);
}
}