i don't know what the empty prototype implies for inlining

Read this and you will (from perldoc perlsub):

Constant Functions

Functions with a prototype of "()" are potential candidates for inlin-
ing.  If the result after optimization and constant folding is either 
+a
constant or a lexically-scoped scalar which has no other references,
then it will be used in place of function calls made without "&".
Calls made using "&" are never inlined.  (See constant.pm for an easy
way to declare most constants.)
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