At cpan, I notice its very common not to properly mention the way error handling is done. I have seen undef, "", 0, throwing exceptions, dieing. Basically if the author doesn't explicitly say what happens, you have to eval the call, then check the result to figure out what it is, or better yet just open the module code and have a look. I prefer to just return empty string, in your particular situation, since it's a value and it's correct in that no name could be obtained.