+static HANDLE timer_event;
+static HANDLE timer_thread;
+static int timer_interval;
+static int one_shot;
+static sig_handler_t timer_fn = SIG_DFL;
+
+/* The timer works like this:
+ * The thread, ticktack(), is a trivial routine that most of the time
+ * only waits to receive the signal to terminate. The main thread tells
+ * the thread to terminate by setting the timer_event to the signalled
+ * state.
+ * But ticktack() interrupts the wait state after the timer's interval
+ * length to call the signal handler.
+ */
+
+static __stdcall unsigned ticktack(void *dummy)
+{
+ while (WaitForSingleObject(timer_event, timer_interval) == WAIT_TIMEOUT) {
+ if (timer_fn == SIG_DFL)
+ die("Alarm");
+ if (timer_fn != SIG_IGN)
+ timer_fn(SIGALRM);
+ if (one_shot)
+ break;
+ }
+ return 0;
+}
+
+static int start_timer_thread(void)
+{
+ timer_event = CreateEvent(NULL, FALSE, FALSE, NULL);
+ if (timer_event) {
+ timer_thread = (HANDLE) _beginthreadex(NULL, 0, ticktack, NULL, 0, NULL);
+ if (!timer_thread )
+ return errno = ENOMEM,
+ error("cannot start timer thread");
+ } else
+ return errno = ENOMEM,
+ error("cannot allocate resources for timer");
+ return 0;
+}
+
+static void stop_timer_thread(void)
+{
+ if (timer_event)
+ SetEvent(timer_event); /* tell thread to terminate */
+ if (timer_thread) {
+ int rc = WaitForSingleObject(timer_thread, 1000);
+ if (rc == WAIT_TIMEOUT)
+ error("timer thread did not terminate timely");
+ else if (rc != WAIT_OBJECT_0)
+ error("waiting for timer thread failed: %lu",
+ GetLastError());
+ CloseHandle(timer_thread);
+ }
+ if (timer_event)
+ CloseHandle(timer_event);
+ timer_event = NULL;
+ timer_thread = NULL;
+}
+
+static inline int is_timeval_eq(const struct timeval *i1, const struct timeval *i2)
+{
+ return i1->tv_sec == i2->tv_sec && i1->tv_usec == i2->tv_usec;
+}
+