io::read!

macro_rules! read {
    () => ({
        read!(io::ffi::BUFF)
    });
    ($len: expr) => ({
        read!($len, 0)
    });
    ($len: expr, $ins: expr) => ({
        extern crate io;
        let line: [i8; io::ffi::BUFF] = [0; io::ffi::BUFF];

        match unsafe {
          io::ffi::read (
            $ins as i32,
            line.as_ptr() as *mut i8,
            $len as i32,
          )
        } {
          -1 => None,
          ret => Some((ret, line)),
        }
    });
}

The read macro reads the input and returns None or the Some of thetuple (len, text).