diff --git a/c/xlib/gcontext.c b/c/xlib/gcontext.c
index eb347f0..2c6b1c0 100644
--- a/c/xlib/gcontext.c
+++ b/c/xlib/gcontext.c
@@ -280,10 +280,12 @@ s48_value scx_Change_Gc(s48_value display, s48_value gc, s48_value values) {
 s48_value scx_Get_Gc_Values(s48_value display, s48_value gc,
 			    s48_value values) {
   unsigned long mask = 0;
+  s48_value i;
   XGCValues GCV;
-  S48_DECLARE_GC_PROTECT_3(display, gc, values);
-  for (; values != S48_NULL; values = S48_CDR(values))
-    mask |= (1L << scx_extract_gc_value(S48_CAR(values)));
+  S48_DECLARE_GC_PROTECT_4(display, gc, values, i);
+
+  for (i = values; i != S48_NULL; i = S48_CDR(i))
+    mask |= (1L << scx_extract_gc_value(S48_CAR(i)));
   
   if (!XGetGCValues(scx_extract_display(display), 
 		    scx_extract_gc(gc),