rust/src/test/run-pass/foreign-call-no-runtime.rs

use std::cast;
use std::libc;
use std::unstable::run_in_bare_thread;

extern {
    pub fn rust_dbg_call(cb: *u8, data: libc::uintptr_t) -> libc::uintptr_t;
}

pub fn main() {
    unsafe {
        do run_in_bare_thread() {
            unsafe {
                let i = &100;
                rust_dbg_call(callback, cast::transmute(i));
            }
        }
    }
}

extern fn callback(data: libc::uintptr_t) {
    unsafe {
        let data: *int = cast::transmute(data);
        assert_eq!(*data, 100);
    }
}