$use StdIO;

$channel C;

Main = {
  <Open-File &C "non-existent" R>;
  <PrintLN "Can't open non-existent file, $fail'ed.">, $fail;
  <Open-File &C "open_file_inv2.rf" XXX>;
  <PrintLN "Unknown mode, $fail'ed.">, $fail;
  <Open-File &C "open_file_inv2.rf" 1>;
};