/* Most systems provide FILE as a struct and the necessary bitmask in
<stdio.h>, because they need it for implementing getc() and putc() as
fast macros. */
-#if defined _IO_ferror_unlocked || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Linux libc5 */
+#if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
return ((fp->_flags & _IO_NO_WRITES) != 0
|| ((fp->_flags & (_IO_NO_READS | _IO_CURRENTLY_PUTTING)) == 0
&& fp->_IO_read_base != NULL));