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//@ run-pass
#![allow(unused_imports)]
use std::sync::Mutex;
use std::thread;
fn par_for<I, F>(iter: I, f: F)
where
I: Iterator,
I::Item: Send,
F: Fn(I::Item) + Sync,
{
for item in iter {
f(item)
}
}
fn sum(x: &[i32]) {
let sum_lengths = Mutex::new(0);
par_for(x.windows(4), |x| *sum_lengths.lock().unwrap() += x.len());
assert_eq!(*sum_lengths.lock().unwrap(), (x.len() - 3) * 4);
}
fn main() {
let mut elements = [0; 20];
// iterators over references into this stack frame
par_for(elements.iter_mut().enumerate(), |(i, x)| *x = i as i32);
sum(&elements)
}
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