/*
=head1 Hash Manipulation Functions
-=for apidoc AmU||HEf_SVKEY
+=for apidoc AmnU||HEf_SVKEY
This flag, used in the length slot of hash entries and magic structures,
specifies the structure contains an C<SV*> pointer where a C<char*> pointer
is to be expected. (For information only--not to be used).
=head1 Handy Values
-=for apidoc AmU||Nullhv
+=for apidoc ADmnU||Nullhv
Null HV pointer.
(deprecated - use C<(HV *)NULL> instead)