G'day cdlvj,

Disclaimer: I can't help you with specifics of "perl dll created by perl Ctrl"; sounds like a MSWin thing (with which I'm unfamiliar).

In many functions, you'll only be interested in the hash's keys and values; the name of &readDirectory suggests it would fall into this category. In these cases, your best choice will probably be:

return { %rlist };
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• There are no references to %rlist when it goes out of scope at the end of &readDirectory: cleanup can occur.
• All callers have a hash which is decoupled from all other callers' hashes and the original %rlist.

In other functions, particularly those that need to modify the hash in some way, a reference to the original hash may be important. In these cases, your best choice will probably be:

return \%rlist;
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• There is one reference to %rlist when it goes out of scope at the end of &readDirectory: cleanup cannot occur.
• All callers have a reference to the same hash; any of which could be modifying the hash in some way, at any time, without notice.

See also: perlreftut, perldsc and perlref.