--- /dev/null
+// SPDX-License-Identifier: LGPL-3.0-or-later
+#ifndef __ALSA_GOBJECT_ALSACTL_PRIVATES__H__
+#define __ALSA_GOBJECT_ALSACTL_PRIVATES__H__
+
+#include <string.h>
+
+#include <glib.h>
+#include <glib-object.h>
+
+G_BEGIN_DECLS
+
+GQuark alsactl_error_quark(void);
+
+#define generate_error(err, errno) \
+ g_set_error(err, alsactl_error_quark(), errno, \
+ __FILE__ ":%d: %s", __LINE__, strerror(errno))
+
+G_END_DECLS
+
+#endif
--- /dev/null
+// SPDX-License-Identifier: LGPL-3.0-or-later
+#include "query.h"
+#include "privates.h"
+
+// For error handling.
+G_DEFINE_QUARK("alsactl-error", alsactl_error)
--- /dev/null
+// SPDX-License-Identifier: LGPL-3.0-or-later
+#ifndef __ALSA_GOBJECT_ALSACTL_QUERY__H__
+#define __ALSA_GOBJECT_ALSACTL_QUERY__H__
+
+#include <glib.h>
+#include <glib-object.h>
+
+G_BEGIN_DECLS
+
+G_END_DECLS
+
+#endif