diff --git a/include/picrin.h b/include/picrin.h
index e34e7659..01c42da5 100644
--- a/include/picrin.h
+++ b/include/picrin.h
@@ -170,7 +170,7 @@ pic_value pic_read_cstr(pic_state *, const char *);
 void pic_load(pic_state *, const char *);
 void pic_load_cstr(pic_state *, const char *);
 
-pic_value pic_funcall(pic_state *pic, const char *, pic_list);
+pic_value pic_funcall(pic_state *pic, struct pic_lib *, const char *, pic_list);
 pic_value pic_ref(pic_state *, struct pic_lib *, const char *);
 void pic_set(pic_state *, struct pic_lib *, const char *, pic_value);
 
diff --git a/port.c b/port.c
index 11ef26ab..b9679e54 100644
--- a/port.c
+++ b/port.c
@@ -25,21 +25,21 @@ pic_eof_object()
 struct pic_port *
 pic_stdin(pic_state *pic)
 {
-  struct pic_proc *proc;
+  pic_value obj;
 
-  proc = pic_proc_ptr(pic_ref(pic, pic->PICRIN_BASE, "current-input-port"));
+  obj = pic_funcall(pic, pic->PICRIN_BASE, "current-input-port", pic_nil_value());
 
-  return pic_port_ptr(pic_apply(pic, proc, pic_nil_value()));
+  return pic_port_ptr(obj);
 }
 
 struct pic_port *
 pic_stdout(pic_state *pic)
 {
-  struct pic_proc *proc;
+  pic_value obj;
 
-  proc = pic_proc_ptr(pic_ref(pic, pic->PICRIN_BASE, "current-output-port"));
+  obj = pic_funcall(pic, pic->PICRIN_BASE, "current-output-port", pic_nil_value());
 
-  return pic_port_ptr(pic_apply(pic, proc, pic_nil_value()));
+  return pic_port_ptr(obj);
 }
 
 struct pic_port *
diff --git a/vm.c b/vm.c
index 72ea96d0..b84bc96e 100644
--- a/vm.c
+++ b/vm.c
@@ -457,11 +457,11 @@ pic_set(pic_state *pic, struct pic_lib *lib, const char *name, pic_value val)
 }
 
 pic_value
-pic_funcall(pic_state *pic, const char *name, pic_list args)
+pic_funcall(pic_state *pic, struct pic_lib *lib, const char *name, pic_list args)
 {
   pic_value proc;
 
-  proc = pic_ref(pic, pic->lib, name);
+  proc = pic_ref(pic, lib, name);
 
   pic_assert_type(pic, proc, proc);