diff --git a/include/picrin/port.h b/include/picrin/port.h
index d5b2eaee..b02c173d 100644
--- a/include/picrin/port.h
+++ b/include/picrin/port.h
@@ -25,4 +25,6 @@ struct pic_port {
 #define pic_port_p(v) (pic_type(v) == PIC_TT_PORT)
 #define pic_port_ptr(v) ((struct pic_port *)pic_ptr(v))
 
+pic_value pic_eof_object();
+
 #endif
diff --git a/src/port.c b/src/port.c
index 0f4a427f..afa84831 100644
--- a/src/port.c
+++ b/src/port.c
@@ -7,6 +7,16 @@
 #include "picrin/blob.h"
 #include "picrin/macro.h"
 
+pic_value
+pic_eof_object()
+{
+  pic_value v;
+
+  pic_init_value(v, PIC_VTYPE_EOF);
+
+  return v;
+}
+
 static void write_pair(pic_state *pic, struct pic_pair *pair);
 static void write_str(pic_state *pic, struct pic_string *str);
 
@@ -312,13 +322,9 @@ pic_port_eof_object_p(pic_state *pic)
 static pic_value
 pic_port_eof_object(pic_state *pic)
 {
-  pic_value v;
-
   pic_get_args(pic, "");
 
-  pic_init_value(v, PIC_VTYPE_EOF);
-
-  return v;
+  return pic_eof_object();
 }
 
 static pic_value