According to, "perldoc -f ref", ref returns a true value if EXPR is a reference, false otherwise. It does not say undef is returned.

A defined test on a "false" value returns true, since even a "false" value is defined.

The following snippet: 

print defined 0 ? 'Y' : 'N';

[download]
prints 'Y'.

In reply to Re: Undefined undef oddness by PrakashK
in thread Undefined undef oddness by Cybercosis

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