minix/lib/libtimers/tmrs_clr.c

   1 #include <minix/timers.h>
   2
   3 /*
   4  * Deactivate a timer and remove it from the timers queue.  'tmrs' is a pointer
   5  * to the timers queue.  'tp' is a pointer to the timer to be removed, which
   6  * generally should be on the queue (but this is not a requirement, and the
   7  * kernel abuses this).  If 'prev_time' is non-NULL, it is filled with the
   8  * previous timer head time, which always exists since at least 'tp' is on it.
   9  * The function returns TRUE if there is still at least one timer on the queue
  10  * after this function is done, in which case 'next_time' (if non-NULL) is
  11  * filled with the absolute expiry time of the new head timer.
  12  */
  13 int
  14 tmrs_clrtimer(minix_timer_t ** tmrs, minix_timer_t * tp, clock_t * prev_time,
  15         clock_t * next_time)
  16 {
  17         minix_timer_t **atp;
  18         int r;
  19
  20         if (*tmrs != NULL) {
  21                 if (prev_time != NULL)
  22                         *prev_time = (*tmrs)->tmr_exp_time;
  23                 r = TRUE;
  24         } else
  25                 r = FALSE;
  26
  27         tp->tmr_func = NULL;    /* clear the timer object */
  28
  29         for (atp = tmrs; *atp != NULL; atp = &(*atp)->tmr_next) {
  30                 if (*atp == tp) {
  31                         *atp = tp->tmr_next;
  32                         break;
  33                 }
  34         }
  35
  36         if (next_time != NULL) {
  37                 if (*tmrs != NULL)
  38                         *next_time = (*tmrs)->tmr_exp_time;
  39                 else
  40                         *next_time = 0;
  41         }
  42
  43         return r;
  44 }