L<Tie::Hash> methods FETCH, STORE, DELETE, CLEAR, EXISTS, FIRSTKEY,
NEXTKEY and SCALAR.
+=head1 CONSTANTS
+
+=head2 C<REP_THREADSAFE>
+
+True iff the module could have been built with thread-safety features
+enabled.
+
+=head2 C<REP_FORKSAFE>
+
+True iff this module could have been built with fork-safety features
+enabled. This will always be true except on Windows where it's false
+for perl 5.10.0 and below.
+
=head1 Tainting
The only way to untaint an existing variable in Perl is to use it as a