- + (fp->_flags & _IO_IN_BACKUP ? fp->_IO_save_end - fp->_IO_save_base :
- 0);
-#elif defined __sferror /* FreeBSD, NetBSD, OpenBSD, MacOS X, Cygwin */
-# if defined __NetBSD__ || defined __OpenBSD__
- struct __sfileext
- {
- struct __sbuf _ub; /* ungetc buffer */
- /* More fields, not relevant here. */
- };
-# define HASUB(fp) (((struct __sfileext *) (fp)->_ext._base)->_ub._base != NULL)
+ + (fp->_flags & _IO_IN_BACKUP ? fp->_IO_save_end - fp->_IO_save_base :
+ 0);
+#elif defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */
+ if ((fp_->_flags & __SWR) != 0 || fp_->_r < 0)
+ return 0;
+# if defined __DragonFly__
+ return __sreadahead (fp);