reentrant function in Rust

reentrant-function-sigaction.rs

use nix::sys::signal::*;
use nix::sys::signal::SigAction;
use std::time::Duration;
use std::thread;

fn calculate(first: i32, second: i32) -> i32 {
    let sum = first + second;
    thread::sleep(Duration::from_secs(3));
    sum
}


extern fn signal_handler(_: i32) {
    let sum: i32 = 50 + 60;
    println!("Interrupt caught!\n");
    println!("Result from signal_handler: {}", sum);
    println!("---\n");
    
}

fn main() {

    let sa = SigAction::new(SigHandler::Handler(signal_handler),
                            SaFlags::empty(),
                            SigSet::empty());

    unsafe {
        sigaction(SIGINT, &sa).unwrap();
    }

    loop {
        println!("Result from main: {}", calculate(3, 5));
        println!("---\n");
    }
}