+=head2 IsMarcStructureInternal
+
+ my $tagslib = C4::Biblio::GetMarcStructure();
+ for my $tag ( sort keys %$tagslib ) {
+ next unless $tag;
+ for my $subfield ( sort keys %{ $tagslib->{$tag} } ) {
+ next if IsMarcStructureInternal($tagslib->{$tag}{$subfield});
+ }
+ # Process subfield
+ }
+
+GetMarcStructure creates keys (lib, tab, mandatory, repeatable) for a display purpose.
+These different values should not be processed as valid subfields.
+
+=cut
+
+sub IsMarcStructureInternal {
+ my ( $subfield ) = @_;
+ return ref $subfield ? 0 : 1;
+}
+