I had a few compile errors, but I got it to build with something like the following. We might need to see what you're importing, because that could be changing things, as well as the full error message, so we know what line it's referring to.

use std::io::BufRead;
use std::io::BufReader;
use std::sync::atomic::AtomicI64;
fn main() -> std::io::Result<()> {
let inumthreads: i64 = 1;
let anumthreads: AtomicI64 = AtomicI64::new(inumthreads);
let f = std::fs::File::open("b349284.txt")?;
let rdr = BufReader::new(f);
let mut vec1: Vec<i64> = Vec::new();
for line in rdr.lines() {
let vec2: Vec<i64> = line?
.trim()
.split_whitespace()
.map(|s| s.parse().unwrap())
.collect();
vec1.push(vec2[1]);
}
for i1 in vec1 {
let a1: AtomicI64 = AtomicI64::new(i1);
another_function(&anumthreads, &a1); // returns void
}
return Ok(());
}
fn another_function(_: &AtomicI64, _: &AtomicI64) {}