--- src/jackbackend.h
+++ src/jackbackend.h
@@ -0,0 +1,23 @@
+/*
+ * jackbackend.h
+ * JACK audio and MIDI backends.
+ *
+ * for Denemo, a gtk+ frontend to GNU Lilypond
+ * Copyright (C) 2011  Dominic Sacré
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef JACKBACKEND_H
+#define JACKBACKEND_H
+
+#include "audiointerface.h"
+
+extern backend_t jack_audio_backend;
+extern backend_t jack_midi_backend;
+
+
+#endif // JACKBACKEND_H
--- src/jackutil.h
+++ src/jackutil.h
@@ -0,0 +1,37 @@
+/*
+ * jackutil.h
+ * JACK utility functions.
+ *
+ * for Denemo, a gtk+ frontend to GNU Lilypond
+ * Copyright (C) 2011  Dominic Sacré
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef JACKUTIL_H
+#define JACKUTIL_H
+
+#include <glib.h>
+
+/**
+ * Returns a list of available JACK port names, that is, ports to which our
+ * own input/output ports can be connected.
+ *
+ * If the JACK server is not running or there are no available ports, this
+ * function returns NULL.
+ *
+ * @param midi    if TRUE returns MIDI ports, otherwise audio ports.
+ * @param output  if TRUE returns output ports, otherwise input ports.
+ */
+GList *get_jack_ports(gboolean midi, gboolean output);
+
+/**
+ * Frees a list returned by get_jack_ports()
+ */
+void free_jack_ports(GList *list);
+
+
+#endif // JACKUTIL_H