Foo.pm ------ use strict; use warnings; sub init { print("Setting \$Foo::bar to 42.\n"); $Foo::bar = 42; } local $Foo::bar; init(); 1; #### main.pl ------- use strict; use warnings; use Foo (); print("\$Foo::bar = $Foo::bar\n"); #### output ------ Setting $Foo::bar to 42. Use of uninitialized value in concatenation (.) or string at main.pl line 7. $Foo::bar =