-XBT_PUBLIC void xbt_os_timer_free(xbt_os_timer_t timer);
-XBT_PUBLIC void xbt_os_timer_start(xbt_os_timer_t timer);
-XBT_PUBLIC void xbt_os_timer_stop(xbt_os_timer_t timer);
-XBT_PUBLIC double xbt_os_timer_elapsed(xbt_os_timer_t timer);
+XBT_PUBLIC(void) xbt_os_timer_free(xbt_os_timer_t timer);
+XBT_PUBLIC(void) xbt_os_timer_start(xbt_os_timer_t timer);
+XBT_PUBLIC(void) xbt_os_timer_stop(xbt_os_timer_t timer);
+XBT_PUBLIC(double) xbt_os_timer_elapsed(xbt_os_timer_t timer);