Clarifications on the hash seed

p4raw-id: //depot/perl@31624

diff --git a/pod/perlrun.pod b/pod/perlrun.pod
index 246d5b3..73850f3 100644 (file)
--- a/pod/perlrun.pod
+++ b/pod/perlrun.pod
@@ -1261,8 +1261,13 @@ X<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.
+things, that hash keys not always be ordered the same between different
+runs of Perl.
+
+Most hashes return elements in the same order as Perl 5.8.0 by default.
+On a hash by hash basis, if pathological data is detected during a hash
+key insertion, then that hash will switch to an alternative random hash
+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
@@ -1270,8 +1275,6 @@ 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.
-This means that each different run of Perl will have a different
-ordering of the results of keys(), values(), and each().
 
 B<Please note that the hash seed is sensitive information>. Hashes are
 randomized to protect against local and remote attacks against Perl