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    use std::ffi::{CStr, CString, NulError, FromBytesWithNulError};
    use std::borrow::Cow;
    use std::os::raw;

    #[derive(Debug)]
    pub struct NullError;

    impl From<NulError> for NullError {
        fn from(_: NulError) -> NullError {
            NullError
        }
    }

    impl From<FromBytesWithNulError> for NullError {
        fn from(_: FromBytesWithNulError) -> NullError {
            NullError
        }
    }

    impl From<NullError> for ::std::io::Error {
        fn from(e: NullError) -> ::std::io::Error {
            ::std::io::Error::new(::std::io::ErrorKind::Other, format!("{}", e))
        }
    }

    impl ::std::error::Error for NullError {
        fn description(&self) -> &str { "non-final null byte found" }
    }

    impl ::std::fmt::Display for NullError {
        fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
            write!(f, "non-final null byte found")
        }
    }

    /// Checks for last byte and avoids allocating if it is zero.
    ///
    /// Non-last null bytes still result in an error.
    pub fn cstr_cow_from_bytes<'a>(slice: &'a [u8]) -> Result<Cow<'a, CStr>, NullError> {
        static ZERO: raw::c_char = 0;
        Ok(match slice.last() {
            // Slice out of 0 elements
            None => unsafe { Cow::Borrowed(CStr::from_ptr(&ZERO)) },
            // Slice with trailing 0
            Some(&0) => Cow::Borrowed(try!(CStr::from_bytes_with_nul(slice))),
            // Slice with no trailing 0
            Some(_) => Cow::Owned(try!(CString::new(slice))),
        })
    }

    #[inline]
    pub fn ensure_compatible_types<T, E>() {
        #[cold]
        #[inline(never)]
        fn dopanic() {
            panic!("value of requested type cannot be dynamically loaded");
        }
        if ::std::mem::size_of::<T>() != ::std::mem::size_of::<E>() {
            dopanic()
        }
    }

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