FAQ 7.13 What is variable suicide and how can I prevent it?

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7.13: What is variable suicide and how can I prevent it?

    Variable suicide is when you (temporarily or permanently) lose the value
    of a variable. It is caused by scoping through my() and local()
    interacting with either closures or aliased foreach() iterator variables
    and subroutine arguments. It used to be easy to inadvertently lose a
    variable's value this way, but now it's much harder. Take this code:

        my $f = "foo";
        sub T {
          while ($i++ < 3) { my $f = $f; $f .= "bar"; print $f, "\n" }
        print "Finally $f\n";

    The $f that has "bar" added to it three times should be a new $f ("my
    $f" should create a new local variable each time through the loop). It
    isn't, however. This was a bug, now fixed in the latest releases (tested
    against 5.004_05, 5.005_03, and 5.005_56).


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