+ timer->elapse.tv_sec = 0;
+ timer->elapse.tv_nsec = 0;
+ clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &(timer->start));
+#elif defined(HAVE_GETTIMEOFDAY)
+ timer->elapse.tv_sec = 0;
+ timer->elapse.tv_usec = 0;
+ gettimeofday(&(timer->start), NULL);
+#else
+ timer->elapse = 0;
+ timer->start = (unsigned long int) (time(NULL));
+#endif
+}
+
+void xbt_os_timer_stop(xbt_os_timer_t timer)
+{
+#ifdef HAVE_POSIX_GETTIME
+ clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &(timer->stop));