1 files changed, 1 insertions, 1 deletions
diff --git a/rubyio.h b/rubyio.h
index e9716c0306..d9e734fa12 100644
--- a/rubyio.h
+++ b/rubyio.h
@@ -47,7 +47,7 @@ typedef struct OpenFile {
 #define FMODE_BINMODE   4
 #define FMODE_SYNC      8
 #define FMODE_LINEBUF  16
-#define FMODE_UNSEEKABLE 32
+#define FMODE_DUPLEX   32
 
 #define GetOpenFile(obj,fp) rb_io_check_closed((fp) = RFILE(rb_io_taint_check(obj))->fptr)