=item MS-DOS
Create a batch file to run your program, and codify it in
-C<ALTERNATIVE_SHEBANG> (see the F<dosish.h> file in the source
+C<ALTERNATE_SHEBANG> (see the F<dosish.h> file in the source
distribution for more information).
=item Win95/NT
=item PERL_HASH_SEED
(Since Perl 5.8.1.) Used to randomise Perl's internal hash function.
+To emulate the pre-5.8.1 behaviour, set to an integer (zero means
+exactly the same order as 5.8.0). "Pre-5.8.1" means, among other
+things, that hash keys will be ordered the same between different runs
+of Perl.
-The default behaviour is B<not> to randomise if the PERL_HASH_SEED is
-unset. If Perl has been compiled with C<-DUSE_HASH_SEED>, the default
-behaviour B<is> to randomise. If Perl hash been compiled with
-C<-DNO_HASH_SEED>, the hash randomisation is completely disabled.
-
-If PERL_HASH_SEED is set to a numeric (positive integer) string,
-that is used as the seed.
+The default behaviour is to randomise unless the PERL_HASH_SEED is set.
+If Perl has been compiled with C<-DUSE_HASH_SEED_EXPLICIT>, the default
+behaviour is B<not> to randomise unless the PERL_HASH_SEED is set.
If PERL_HASH_SEED is unset or set to a non-numeric string, Perl uses
the pseudorandom seed supplied by the operating system and libraries.
-
-The seed being set means that each different run of Perl will have
-a different ordering of the results of keys(), values(), and each().
+This means that each different run of Perl will have a different
+ordering of the results of keys(), values(), and each().
See L<perlsec/"Algorithmic Complexity Attacks"> for more information.