You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: signal.rs
    path of file: ./repos/nix/src/sys
    
    the code of the file until where you have to start completion: // Portions of this file are Copyright 2014 The Rust Project Developers.
// See https://www.rust-lang.org/policies/licenses.

//! Operating system signals.

use crate::errno::Errno;
use crate::{Error, Result};
use cfg_if::cfg_if;
use std::fmt;
use std::hash::{Hash, Hasher};
use std::mem;
use std::ops::BitOr;
#[cfg(freebsdlike)]
use std::os::unix::io::RawFd;
use std::ptr;
use std::str::FromStr;

#[cfg(not(any(
    target_os = "fuchsia",
    target_os = "hurd",
    target_os = "openbsd",
    target_os = "redox"
)))]
#[cfg(any(feature = "aio", feature = "signal"))]
pub use self::sigevent::*;

#[cfg(any(feature = "aio", feature = "process", feature = "signal"))]
libc_enum! {
    /// Types of operating system signals
    // Currently there 
    
            fn hash<H: hash::Hasher>(&self, s: &mut H) {
                self.sigev_notify.hash(s);
                self.sigev_signo.hash(s);
                self.sigev_value.hash(s);
                // Safe because we check the sigev_notify discriminant
                unsafe {
                    match self.sigev_notify {
                        libc::SIGEV_KEVENT => {
                            self._sigev_un._kevent_flags.hash(s);
                        }
                        libc::SIGEV_THREAD_ID => {
                            self._sigev_un._threadid.hash(s);
                        }
                        libc::SIGEV_THREAD => {
                            self._sigev_un._sigev_thread.hash(s);
                        }
                        _ => /* The union field is don't care */ ()
                    }
                }
            }