+DH_check_params() confirms that the B<p> and B<g> are likely enough to
+be valid.
+This is a lightweight check, if a more thorough check is needed, use
+DH_check().
+The value of B<*codes> is updated with any problems found.
+If B<*codes> is zero then no problems were found, otherwise the
+following bits may be set:
+
+=over 4
+
+=item DH_CHECK_P_NOT_PRIME
+
+The parameter B<p> has been determined to not being an odd prime.
+Note that the lack of this bit doesn't guarantee that B<p> is a
+prime.
+
+=item DH_NOT_SUITABLE_GENERATOR
+
+The generator B<g> is not suitable.
+Note that the lack of this bit doesn't guarantee that B<g> is
+suitable, unless B<p> is known to be a strong prime.
+
+=back
+