代码Profile

#ifdef DEBUG_CODES_TIME
void timer_start(timespec *aStartTime)
{
      clock_gettime(CLOCK_REALTIME, aStartTime);
}
long timer_end(timespec *aStartTime)
{
      timespec endTime;
      clock_gettime(CLOCK_REALTIME, &endTime);
      long totalTimeMs = (endTime.tv_sec * 1000 + endTime.tv_nsec / 1000000) - (aStartTime->tv_sec * 1000 + aStartTime->tv_nsec / 1000000);
      return totalTimeMs;
}
clock_t _timing_clock = 0;
void timer_handler(int sig)
{
    _timing_clock = clock();
}
__attribute((constructor)) void timing_init()
{
      signal(SIGALRM, timer_handler);
      struct itimerval tick;
      memset(&tick, 0, sizeof(tick));
      tick.it_value.tv_usec = 1;
      tick.it_interval.tv_usec = 10000; //微秒
      setitimer(ITIMER_REAL, &tick, NULL);
      printf("(debug) initialize timing clock to %f seconds\n", tick.it_interval.tv_usec / 1000000.0);
}
#else
#define timer_start(ts)
#define timer_end(ts) -1
#endif


int main()
{
  timespec ts;
  timer_start(&ts);
  for(int i=0; i<1000000; ++i);
  long ret = timer_end(&ts);
  printf("Result: %ld \n",ret);
  return 0; 

}

调试版：

$g++ test_timer.c -DDEBUG_CODES_TIME -lrt
$./a.out
(debug) initialize timing clock to 0.010000 seconds

Result: 4

发布版：

$g++ test_timer.c -lrt
$./a.out
Result: -1