In order to write future-proof code, it is recommended that you prefix (or suffix) anything that goes into the global namespace with an uncommon 3-4 letter prefix (or suffix) separated with an underscore. It is recommended that in order to prevent namespace clashes with other userland code that projects research existing prefixes (or suffixes) used in other projects and advertise their chosen prefix (or suffix) appropriately. Examples:
MyPx_someFunc()
Foo_Date
$asdf_dbh