diff --git a/src/refl/BuildOption.cs b/src/refl/BuildOption.cs
index f920b48..e8713a7 100644
--- a/src/refl/BuildOption.cs
+++ b/src/refl/BuildOption.cs
@@ -59,18 +59,13 @@ namespace refl
             }
             return parse;
         }
-        public static List<string> PrepareFileList(List<string> file_list)
+        public static string PreprocessFile(string file_path)
         {
             StringBuilder code = new StringBuilder();
-            foreach (var file in file_list)
-            {
-                string fileContent = File.ReadAllText(file);
-                code.AppendLine(fileContent.Replace("#include", "//#include"));
-            }
-            file_list.Clear();
-            file_list.Add(InputFile);
+            string fileContent = File.ReadAllText(file_path);
+            code.AppendLine(fileContent.Replace("#include", "//#include"));
             File.WriteAllText(InputFile, code.ToString());
-            return file_list;
+            return InputFile;
         }
         public static int CMD_CheckBuildOption(CmdBuildOption opt)
         {
@@ -89,7 +84,12 @@ namespace refl
             {
                 file_list = opt.InputFiles.Skip(1).ToList();
             }
-            var compilation = CppAst.CppParser.ParseFiles(PrepareFileList(file_list), parse_opt);
+            int index = file_list.Count - 1;
+            if(index >= 0)
+            {
+                file_list[index] = PreprocessFile(file_list[index]);
+            }
+            var compilation = CppAst.CppParser.ParseFiles(file_list, parse_opt);
             if (opt.Verbose)
             {
                 // Print diagnostic messages