How to know the version of a package ?

Hi everybody. I'd like to make some of my tools built around Structures_DataGrid compatible with the new release, while keeping backward compatibility. So I have to check somewhere in my code which version of SDG is running. Is there a pear php extension that can do that (return the version of a package) I checked in the documentation for PEAR::Info, PEAR::PackageFileManager, PEAR::PackageUpdate, PHP_Compat but did not find anything that could achieve that purpose Thanx