How to send output to stderr?

Question

One uses this to send output to stdout:

println!(\"some output\")

I think there is no corresponding macro to do the same for stderr.

Answer 1

Goal

stderr!("Code {}: Danger, Will Robinson!  Danger!", 42);

Notes

The other answers generate an unused import warning with the latest nightly, so here's a modern macro that Just Works TM.

Code

macro_rules! stderr {
    ($($arg:tt)*) => (
        use std::io::Write;
        match writeln!(&mut ::std::io::stderr(), $($arg)* ) {
            Ok(_) => {},
            Err(x) => panic!("Unable to write to stderr (file handle closed?): {}", x),
        }
    )
}