ffi.rb in ngt-0.2.0

- old
+ new
@@ -54,7 +54,17 @@
     attach_function :ngt_destroy_property, %i[pointer], :void
     attach_function :ngt_close_index, %i[pointer], :void
     attach_function :ngt_create_error_object, %i[], :pointer
     attach_function :ngt_get_error_string, %i[pointer], :string
     attach_function :ngt_destroy_error_object, %i[pointer], :void
+
+    begin
+      attach_function :ngt_create_optimizer, %i[bool pointer], :pointer
+      attach_function :ngt_optimizer_adjust_search_coefficients, %i[pointer string pointer], :bool
+      attach_function :ngt_optimizer_execute, %i[pointer string string pointer], :bool
+      attach_function :ngt_optimizer_set, %i[pointer int int int float float float float double double pointer], :bool
+      attach_function :ngt_destroy_optimizer, %i[pointer], :void
+    rescue ::FFI::NotFoundError
+      # only available in 1.8.1+
+    end
   end
 end