use vars qw($frob @mung %seen);
Unlike pragmas that affect the $^H
hints variable, the use vars
and
use subs
declarations are not BLOCK-scoped. They are thus effective for the entire
file in which they appear. You may not rescind such declarations with no vars
or no subs
.
Packages such as the AutoLoader and SelfLoader that delay loading of subroutines within packages can create problems with package lexicals defined using my. While the vars pragma cannot duplicate the effect of package lexicals (total transparency outside of the package), it can act as an acceptable substitute by pre-declaring global symbols, ensuring their availability to to the later-loaded routines.
See Pragmatic Modules.