undef ne $string if $string is a defined value.

Sorry, but no: $string = "" is a defined value, and undef eq "". What's happening is that eq forces string context on its arguments and undef is converted to "", with a warning, which of course is the same thing as the string "". eq is not a test for definedness, only defined does that - undef eq undef not because they are both undef, but because "" eq "".

In reply to Re^2: The error says the value is uninitialized, but it works anyway by haukex
in thread The error says the value is uninitialized, but it works anyway by mizducky

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