p>Please do three things. First: add

use warnings FATAL => qw(all);
use strict;
use Data::Dump qw(dump pp);
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Second: eliminate the undef $pt line, try restoring to a different variable using my $pt2 for example. Third: could you supply an example of a minimal set of input data that causes a SEGV on your system? The easiest way would be via dump(). Thanks