diff --git a/ChangeLog b/ChangeLog
index 2e832c014e..8d0c02b94c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Tue Oct 21 13:28:42 2008  Shugo Maeda  <shugo@ruby-lang.org>
+
+	* io.c, include/ruby/intern.h (rb_io_ascii8bit_binmode): externed.
+
+	* ext/socket/socket.c (init_sock): use rb_io_ascii8bit_binmode()
+	  instead of rb_io_binmode().
+
 Tue Oct 21 13:17:39 2008  Yuki Sonoda (Yugui)  <yugui@yugui.jp>
 
 	* mdoc2man.rb: moved into tools/.
diff --git a/ext/socket/socket.c b/ext/socket/socket.c
index 65e7d9827f..e52ec9493a 100644
--- a/ext/socket/socket.c
+++ b/ext/socket/socket.c
@@ -241,7 +241,7 @@ init_sock(VALUE sock, int fd)
     MakeOpenFile(sock, fp);
     fp->fd = fd;
     fp->mode = FMODE_READWRITE|FMODE_DUPLEX;
-    rb_io_binmode(sock);
+    rb_io_ascii8bit_binmode(sock);
     if (do_not_reverse_lookup) {
 	fp->mode |= FMODE_NOREVLOOKUP;
     }
diff --git a/include/ruby/intern.h b/include/ruby/intern.h
index 6472ee8ced..ce6221cc23 100644
--- a/include/ruby/intern.h
+++ b/include/ruby/intern.h
@@ -382,6 +382,7 @@ VALUE rb_io_close(VALUE);
 VALUE rb_io_flush(VALUE);
 VALUE rb_io_eof(VALUE);
 VALUE rb_io_binmode(VALUE);
+VALUE rb_io_ascii8bit_binmode(VALUE);
 VALUE rb_io_addstr(VALUE, VALUE);
 VALUE rb_io_printf(int, VALUE*, VALUE);
 VALUE rb_io_print(int, VALUE*, VALUE);
diff --git a/io.c b/io.c
index 29be9e13ee..527f9db007 100644
--- a/io.c
+++ b/io.c
@@ -3514,7 +3514,7 @@ rb_io_binmode(VALUE io)
     return io;
 }
 
-static VALUE
+VALUE
 rb_io_ascii8bit_binmode(VALUE io)
 {
     rb_io_t *fptr;