MAKE_CLASSES:
printf $temporaryLog "%s : Enter loop %d keys ...", scalar localtime(), scalar keys %c;
    foreach my $subclass ( sort { length $a <=> length $b } keys %c )
    {
     ...
    }
printf $temporaryLog "exited\n";

##</code><code>##

perl -d:Trace yourscript.pl 2>yourlog

##</code><code>##

BEGIN{ close STDERR; open STDERR, '>', "$$.log" }
END{ close STDERR; unlink "$$.log"; }