lib/libtimers/tmrs_set.c

   1 #include "timers.h"
   2
   3 /*===========================================================================*
   4  *                              tmrs_settimer                                *
   5  *===========================================================================*/
   6 clock_t tmrs_settimer(tmrs, tp, exp_time, watchdog, new_head)
   7 timer_t **tmrs;                         /* pointer to timers queue */
   8 timer_t *tp;                            /* the timer to be added */
   9 clock_t exp_time;                       /* its expiration time */
  10 tmr_func_t watchdog;                    /* watchdog function to be run */
  11 clock_t *new_head;                      /* new earliest timer, if non NULL */
  12 {
  13 /* Activate a timer to run function 'fp' at time 'exp_time'. If the timer is
  14  * already in use it is first removed from the timers queue. Then, it is put
  15  * in the list of active timers with the first to expire in front.
  16  * The caller responsible for scheduling a new alarm for the timer if needed.
  17  */
  18   timer_t **atp;
  19   clock_t old_head = 0;
  20
  21   if(*tmrs)
  22         old_head = (*tmrs)->tmr_exp_time;
  23
  24   /* Set the timer's variables. */
  25   (void) tmrs_clrtimer(tmrs, tp, NULL);
  26   tp->tmr_exp_time = exp_time;
  27   tp->tmr_func = watchdog;
  28
  29   /* Add the timer to the active timers. The next timer due is in front. */
  30   for (atp = tmrs; *atp != NULL; atp = &(*atp)->tmr_next) {
  31         if (exp_time < (*atp)->tmr_exp_time) break;
  32   }
  33   tp->tmr_next = *atp;
  34   *atp = tp;
  35   if(new_head)
  36         (*new_head) = (*tmrs)->tmr_exp_time;
  37   return old_head;
  38 }
  39