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use crate::cpu::LoadAvg;

use libc::{c_double, getloadavg};
use std::io::Error;

/// Returns the [LoadAvg] over the last 1, 5 and 15 minutes.
///
/// In Linux, the [LoadAvg] is technically believed to be a running average
/// of processes in it’s (kernel) execution queue tagged as running or uninterruptible.
///
/// [LoadAvg]: ../cpu/struct.LoadAvg.html
pub fn get_loadavg() -> Result<LoadAvg, Error> {
    let mut data: [c_double; 3] = [0.0, 0.0, 0.0];

    if unsafe { getloadavg(data.as_mut_ptr(), 3) } == -1 {
        return Err(Error::last_os_error());
    }

    Ok(LoadAvg {
        one: data[0],
        five: data[1],
        fifteen: data[2],
    })
}