newbie: detect method deprecation reflectively?

(Apologies if this is duplicate - Google gave me an error on my first try.)

I'd like to check reflectively whether a method is deprecated, but I don't see a method or attribute to do that. I do see   http://www.koders.com/ruby/ fid293CE25280F60CB0933EAA05FDD489E4532CFF16.aspx?s=proxy

But it's not in my system (ruby 1.8.5 (2006-08-25) [i386-mswin32], Rails 1.1.6). It should be possible to do this since the system issues deprecation warnings.

Hints?

Thanks in advance -