1 files changed, 1 insertions, 0 deletions
diff --git a/intern.h b/intern.h
index ef2eaaecd5..8bc30db0e7 100644
--- a/intern.h
+++ b/intern.h
@@ -278,6 +278,7 @@ VALUE rb_io_gets _((VALUE));
 VALUE rb_io_getc _((VALUE));
 VALUE rb_io_ungetc _((VALUE, VALUE));
 VALUE rb_io_close _((VALUE));
+VALUE rb_io_flush _((VALUE));
 VALUE rb_io_eof _((VALUE));
 VALUE rb_io_binmode _((VALUE));
 VALUE rb_io_addstr _((VALUE, VALUE));