src/test/run-make-fulldeps/extern-fn-with-union/test.rs

extern crate testcrate;

use std::mem;

extern {
    fn give_back(tu: testcrate::TestUnion) -> u64;
}

fn main() {
    let magic: u64 = 0xDEADBEEF;

    // Let's test calling it cross crate
    let back = unsafe {
        testcrate::give_back(mem::transmute(magic))
    };
    assert_eq!(magic, back);

    // And just within this crate
    let back = unsafe {
        give_back(mem::transmute(magic))
    };
    assert_eq!(magic, back);
}