-#ifdef DKIOCGETBLOCKCOUNT /* For Apple Darwin */
- if (ioctl(fd, DKIOCGETBLOCKCOUNT, &size64) >= 0) {
+#if defined DKIOCGETBLOCKCOUNT && defined DKIOCGETBLOCKSIZE /* For Apple Darwin */
+ unsigned int size;
+
+ if (ioctl(fd, DKIOCGETBLOCKCOUNT, &size64) >= 0 &&
+ ioctl(fd, DKIOCGETBLOCKSIZE, &size) >= 0) {