src/test/run-pass/packed-struct-generic-layout.rs

   1 // Copyright 2013 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11
  12 use std::mem;
  13
  14 #[repr(packed)]
  15 struct S<T, S> {
  16     a: T,
  17     b: u8,
  18     c: S
  19 }
  20
  21 pub fn main() {
  22     unsafe {
  23         let s = S { a: 0xff_ff_ff_ffu32, b: 1, c: 0xaa_aa_aa_aa as i32 };
  24         let transd : [u8; 9] = mem::transmute(s);
  25         // Don't worry about endianness, the numbers are palindromic.
  26         assert_eq!(transd,
  27                    [0xff, 0xff, 0xff, 0xff,
  28                     1,
  29                     0xaa, 0xaa, 0xaa, 0xaa]);
  30
  31
  32         let s = S { a: 1u8, b: 2u8, c: 0b10000001_10000001 as i16};
  33         let transd : [u8; 4] = mem::transmute(s);
  34         // Again, no endianness problems.
  35         assert_eq!(transd,
  36                    [1, 2, 0b10000001, 0b10000001]);
  37     }
  38 }