+/*
+ * This file is part of the libserialport project.
+ *
+ * Copyright (C) 2019 Martin Ling <martin-libserialport@earth.li>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * We can't include DDK headers in serialport.c because they conflict with
+ * user space headers. So this file exists to isolate the definitions which
+ * use the kernel declarations.
+ */
+
+#include <ddk/wdm.h>
+
+const size_t WRITEFILE_MAX_SIZE = ((65535 - sizeof(MDL)) / sizeof(ULONG_PTR)) * PAGE_SIZE;