#include <sys/time.h>

/*
 * Uses UNIX timers to start timing an interval 
 */
void start_timer()
{
  struct itimerval  pval, poval;

  pval.it_value.tv_sec = 1000000;
  pval.it_value.tv_usec = 0;
  pval.it_interval.tv_sec = 0;
  pval.it_interval.tv_usec = 0;
  setitimer(ITIMER_PROF, &pval, &poval);
}

/* 
 * Returns process seconds elapsed since last call to start_timer()    
 */
double num_seconds() 
{
  struct itimerval  val;
  long  secs, usecs;

  getitimer(ITIMER_PROF, &val);
  secs = 1000000 - val.it_value.tv_sec - 1;
  usecs = 1000000 - val.it_value.tv_usec;

  return (double) secs + (double) usecs/1000000.0;
}

/************************************************************************
************************************************************************/