diff --git a/ChangeLog b/ChangeLog
index d5fa990494..2f3303e480 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Aug 21 15:13:08 2009  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* include/ruby/io.h, io.c (FMODE_SETENC_BY_BOM):
+	  renamed from FMODE_STRIP_BOM.
+
 Thu Aug 20 01:24:55 2009  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* io.c (rb_io_fmode_modestr): change modestr syntax for BOM
diff --git a/include/ruby/io.h b/include/ruby/io.h
index 7d9512aa92..45384db586 100644
--- a/include/ruby/io.h
+++ b/include/ruby/io.h
@@ -94,7 +94,7 @@ typedef struct rb_io_t {
 #define FMODE_TEXTMODE              0x00001000
 #define FMODE_EOF                   0x00002000
 /* #define FMODE_PREP               0x00010000 */
-#define FMODE_STRIP_BOM             0x00100000
+#define FMODE_SETENC_BY_BOM         0x00100000
 
 #define GetOpenFile(obj,fp) rb_io_check_closed((fp) = RFILE(rb_io_taint_check(obj))->fptr)
 
diff --git a/io.c b/io.c
index fe2a6cd1f6..b7e278083c 100644
--- a/io.c
+++ b/io.c
@@ -3989,7 +3989,7 @@ rb_io_modestr_fmode(const char *modestr)
     if ((fmode & FMODE_BINMODE) && (fmode & FMODE_TEXTMODE))
         goto error;
     if (p && io_encname_bom_p(p, 0))
-	fmode |= FMODE_STRIP_BOM;
+	fmode |= FMODE_SETENC_BY_BOM;
 
     return fmode;
 }
@@ -4334,7 +4334,7 @@ rb_io_extract_modeenc(VALUE *vmode_p, VALUE *vperm_p, VALUE opthash,
             has_enc = 1;
             parse_mode_enc(p+1, &enc, &enc2);
 	    if (io_encname_bom_p(p+1, 0))
-		fmode |= FMODE_STRIP_BOM;
+		fmode |= FMODE_SETENC_BY_BOM;
         }
 	else {
 	    rb_encoding *e;
@@ -4634,7 +4634,7 @@ rb_file_open_generic(VALUE io, VALUE filename, int oflags, int fmode, convconfig
     fptr->pathv = rb_str_new_frozen(filename);
     fptr->fd = rb_sysopen(fptr->pathv, oflags, perm);
     io_check_tty(fptr);
-    if (fmode & FMODE_STRIP_BOM) io_set_encoding_by_bom(io);
+    if (fmode & FMODE_SETENC_BY_BOM) io_set_encoding_by_bom(io);
 
     return io;
 }
@@ -6400,7 +6400,7 @@ rb_io_initialize(int argc, VALUE *argv, VALUE io)
     else if (fileno(stderr) == fd)
 	fp->stdio_file = stderr;
 
-    if (fmode & FMODE_STRIP_BOM) io_set_encoding_by_bom(io);
+    if (fmode & FMODE_SETENC_BY_BOM) io_set_encoding_by_bom(io);
     return io;
 }