allows you to do my $var; $var += 3; without warning as well.

That's interesting. I would have figured it would warn of an uninitialized variable.

This was all I could find:
Use of uninitialized value%s 
(W uninitialized) An undefined value was used as if it 
were already defined. It was interpreted as a "" or a 0, 
but maybe it was a mistake. To suppress this warning 
assign a defined value to your variables.

To help you figure out what was undefined, perl tells you 
what operation you used the undefined value in. Note, 
however, that perl optimizes your program and the 
operation displayed in the warning may not necessarily 
appear literally in your program. For example, "that $foo" 
is usually optimized into "that " . $foo , and the warning 
will refer to the concatenation (.) operator, even though 
there is no . in your program.

[download]


What is the reasoning behind this?

In reply to Re^2: I've been bit in the neck by open() by RazorbladeBidet
in thread I've been bit in the neck by open() by blazar

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