++ysth is correct about named vs anonymous subroutines. Another confusing issue is that the first argument to find() can be either a code reference or a hash reference. In the simpler case, where you have no special options to set, you just make the first argument a *code* reference; a reference to the "callback" sub. The sub is always named "wanted" in the documentation, but it can have any name, or be a anonymous sub.

find(
   \&some_subroutine,
   @directories_to_search,
);
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If you need to set a special option in find(), like 'no_chdir', then you pass a *hash* reference as the first argument. The code reference (that you would have used as the first argument in the simpler case) becomes the 'wanted' option.

find(
   {
      wanted => \&some_subroutine,
      other_option  => 'other_option_value',
      # ...
   },
   @directories_to_search,
);
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