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So maybe because $2 from my previous regex is undef, $tmp2 becomes undef resulting in the warning.. this makes sense. You shouldn't be even using $2 if the match that was supposed to give it a value failed. You must rework your script's logic so that $2 is only being used if the match that loaded it succeeded. In fact, it's dangerous to simply assume that if $2 is undefined if the previous match failed. Such is not always the case. It's even dangerous to assume anything about $2 unless you KNOW that the previous match succeeded. Take a look at the following contrived snippet:
And the output is:
This tells us that $2, which gains a value during the first match, retains that value even though the second match failed. In other words, even though you gave the possibility for $2 to gain a new value in the second match, it retained the original value because the second match failed. That means that it is unreliable to just assume $2 is going to be undef if the most recent match failed, because it could possibly be holding some value from a previous pattern match. Go back to the drawing board with regards to your program's logic. ;) Now in regards to how to avoid an "undefined" warning, just check for definedness before doing anything with it. Please note, this solution is a stopgap measure, and won't fix the underlying bug in your script. I am providing this only because you essentially asked how to do something only if a scalar holds a defined value:
Enjoy! I hope all this helps...
Dave In reply to Re: Re: Re: Use of uninitialized value in pattern match (m//)
by davido
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