When you say "fails", do you mean "needs to return 0", or do you mean "throws an exception"? Because then this:

  my $response = doSomething ();

  sub doSomething {
    #..do something which fails
    0;
  }
[download]

Might become:

  my $response = doSomething ();

  sub doSomething {
    eval
    {
      #..do something which fails
    };

    if ($@)
    {
      # handle the error
    }
    0;
  }
[download]