diff --git a/src/rc/rc-logger.h b/src/rc/rc-logger.h
index ef157a87..510858b0 100644
--- a/src/rc/rc-logger.h
+++ b/src/rc/rc-logger.h
@@ -24,9 +24,14 @@
  * SUCH DAMAGE.
  */
 
+#ifndef RC_LOGGER_H
+#define RC_LOGGER_H
+
 pid_t rc_logger_pid;
 int rc_logger_tty;
 extern bool rc_in_logger;
 
-void rc_logger_open (const char *runlevel);
-void rc_logger_close ();
+void rc_logger_open(const char *runlevel);
+void rc_logger_close(void);
+
+#endif