// 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 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. /*! * C-like enums have to be represented as LLVM ints, not wrapped in a * struct, because it's important for the FFI that they interoperate * with C integers/enums, and the ABI can treat structs differently. * For example, on i686-linux-gnu, a struct return value is passed by * storing to a hidden out parameter, whereas an integer would be * returned in a register. * * This test just checks that the ABIs for the enum and the plain * integer are compatible, rather than actually calling C code. * The unused parameter to `foo` is to increase the likelihood of * crashing if something goes wrong here. */ #[repr(u32)] enum Foo { A = 0, B = 23 } #[inline(never)] extern "C" fn foo(_x: uint) -> Foo { Foo::B } pub fn main() { unsafe { let f: extern "C" fn(uint) -> u32 = ::std::mem::transmute(foo); assert_eq!(f(0xDEADBEEF), Foo::B as u32); } }