XBT_PUBLIC void xbt_os_sleep(double sec);
typedef struct s_xbt_os_timer *xbt_os_timer_t;
+typedef const struct s_xbt_os_timer* const_xbt_os_timer_t;
XBT_PUBLIC xbt_os_timer_t xbt_os_timer_new(void);
XBT_PUBLIC void xbt_os_timer_free(xbt_os_timer_t timer);
-XBT_PUBLIC double xbt_os_timer_elapsed(xbt_os_timer_t timer);
+XBT_PUBLIC double xbt_os_timer_elapsed(const_xbt_os_timer_t timer);
XBT_PUBLIC size_t xbt_os_timer_size(void);
XBT_PUBLIC void xbt_os_walltimer_start(xbt_os_timer_t timer);