/******************************************/
/* timer.h 0.2.0 (1999-Nov-13-Sat)        */
/* Adam M. Costello <amc@cs.berkeley.edu> */
/******************************************/

/* Get the current time, set timers that cause functions */
/* to be called in the future, and cancel timers.        */

/* This is ANSI C code. */


#ifndef TIMER_H
#define TIMER_H


typedef struct {
  struct timer *timer;
  unsigned long serial;
} timer_id;

    /* An identifier for a running timer, used to cancel the timer. */
    /* Treat this as on opaque type (don't try to look inside).     */


typedef void timer_handler(double now, void *who, void *what);

    /* A timer_handler is a function that gets called when a timer  */
    /* expires, and has the form expire(now,who,what), where now is */
    /* the current time in seconds, and who and what are arbitrary  */
    /* pointers specified when the timer was set.  See timer_set()  */
    /* below.                                                       */


double timer_now(void);

    /* Returns the current time in seconds.  The origin */
    /* (the time corresponding to 0) is unspecified.    */


timer_id timer_set(timer_handler *expire, double when, void *who, void *what);

    /* Sets a timer.  When the indicated time arrives the  */
    /* function expire(when,who,what) will be called.  The */
    /* who and what arguments can be anything, they are    */
    /* simply passed along.  The returned timer_id can be  */
    /* passed to timer_cancel() to cancel the timer.  If   */
    /* multiple timers are scheduled to expire at the same */
    /* time, they will expire in the order they were set.  */
    /* If the requested expiration time is in the past, it */
    /* is changed to the current time.                     */


int timer_cancel(timer_id timer);

    /* The timer must have been returned by timer_set().  If it is */
    /* still running (has not yet expired or been canceled), it is */
    /* canceled and 1 is returned, otherwise 0 is returned.        */


#endif /* TIMER_H */