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use clint::Handler;
// Wrapper used to call through to `example_handler` via `closure` in
// `main`. `Handler::new()` places a do-nothing handler in this at
// compile-time, in case the interrupt using this handler is fired
// before being `replace`d in `main`.
static mut HANDLER: Handler = Handler::new();
fn main() {
let mut x: u32 = 0;
// Create a closure to take a mutable reference to `x` for use in
// `example_handler`.
let closure = move || example_handler(&mut x);
// Swap out the do-nothing handler with our closure that calls
// through to `example_handler`. Ideally, the interrupt which uses
// this handler would be disabled while this happens, but as this
// is a demo, and there aren't any actual interrupts firing, this
// is left as an exercise to the reader.
unsafe { HANDLER.replace(&closure) };
// Simulate firing the interrupt.
dummy_interrupt();
dummy_interrupt();
// Because `x` is `Copy`, we still have access to the symbol,
// although its value won't be changed by `closure`.
println!("x(o): {}", x);
}
// Not a real interrupt handler, but called like one. i.e.: simple
// function with no arguments.
//
// Calls through `HANDLER` to do its actual work.
fn dummy_interrupt() {
unsafe { HANDLER.call() };
}
// The meat of the interrupt handler, which does work with whatever
// params were passed in via `closure` in `main`.
fn example_handler(x: &mut u32) {
// Update our dummy value, just to show it works.
*x += 2;
println!("x: {}", x);
}
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