+ int wakeup_fd = shm_get_wakeup_fd(handle, &buf->self._ref);
+
+ if (wakeup_fd >= 0) {
+ int ret;
+ /*
+ * Wake-up the other end by
+ * writing a null byte in the
+ * pipe (non-blocking).
+ * Important note: Because
+ * writing into the pipe is
+ * non-blocking (and therefore
+ * we allow dropping wakeup
+ * data, as long as there is
+ * wakeup data present in the
+ * pipe buffer to wake up the
+ * consumer), the consumer
+ * should perform the following
+ * sequence for waiting:
+ * 1) empty the pipe (reads).
+ * 2) check if there is data in
+ * the buffer.
+ * 3) wait on the pipe (poll).
+ */
+ do {
+ ret = write(wakeup_fd, "", 1);
+ } while (ret == -1L && errno == EINTR);
+ }