diff --git a/src/h/internal.h b/src/h/internal.h
new file mode 100644
index 000000000..6310be26c
--- /dev/null
+++ b/src/h/internal.h
@@ -0,0 +1,55 @@
+/*
+    internal.h -- Structures and functions that are not meant for the end user
+*/
+/*
+    Copyright (c) 2001, Juan Jose Garcia Ripoll.
+
+    ECL is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Library General Public
+    License as published by the Free Software Foundation; either
+    version 2 of the License, or (at your option) any later version.
+
+    See file '../Copyright' for full details.
+*/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* all_functions.d */
+
+extern const struct {
+	const char *name;
+	cl_object (*f)(int, ...);
+	short type;
+} all_functions[];
+
+
+/* print.d */
+
+#define ECL_PPRINT_QUEUE_SIZE			128
+#define ECL_PPRINT_INDENTATION_STACK_SIZE	256
+
+#ifndef THREADS
+extern bool PRINTescape;
+extern bool PRINTpretty;
+extern bool PRINTcircle;
+extern int PRINTbase;
+extern bool PRINTradix;
+extern cl_object PRINTcase;
+extern bool PRINTgensym;
+extern int PRINTlevel;
+extern int PRINTlength;
+extern bool PRINTarray;
+extern cl_object PRINTpackage;
+extern bool PRINTstructure;
+extern cl_object PRINTstream;
+#endif
+
+extern void edit_double(int n, double d, int *sp, char *s, int *ep);
+extern void cl_setup_printer(cl_object strm);
+extern void cl_write_object(cl_object x);
+
+#ifdef __cplusplus
+}
+#endif