diff --git a/src/org/jruby/ext/posix/HeapStruct.java b/src/org/jruby/ext/posix/HeapStruct.java
index 02530f2..5f51e0b 100644
--- a/src/org/jruby/ext/posix/HeapStruct.java
+++ b/src/org/jruby/ext/posix/HeapStruct.java
@@ -34,6 +34,7 @@ package org.jruby.ext.posix;
 import com.sun.jna.FromNativeContext;
 import com.sun.jna.Platform;
 import com.sun.jna.Pointer;
+import java.lang.reflect.Constructor;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 
@@ -96,6 +97,19 @@ public class HeapStruct implements com.sun.jna.NativeMapped {
             this.offset = addField(size, align);
         }
     }
+    @SuppressWarnings("unchecked")
+    protected <T extends Field> T[] array(T[] array) {
+        for (int i = 0; i < array.length; ++i) {
+            try {
+                Class<?> arrayClass = array.getClass().getComponentType();
+                Constructor<?> ctor = arrayClass.getDeclaredConstructor(new Class[] { arrayClass.getEnclosingClass() });
+                array[i] = (T) ctor.newInstance(new Object[] { HeapStruct.this });
+            } catch (Exception ex) {
+                throw new RuntimeException(ex);    
+            }
+        }
+        return array;
+    }
     protected class Int8 extends Field {
         public Int8() {
             super(8);
diff --git a/src/org/jruby/ext/posix/MacOSHeapFileStat.java b/src/org/jruby/ext/posix/MacOSHeapFileStat.java
index ae72023..c2e8303 100644
--- a/src/org/jruby/ext/posix/MacOSHeapFileStat.java
+++ b/src/org/jruby/ext/posix/MacOSHeapFileStat.java
@@ -53,8 +53,7 @@ public class MacOSHeapFileStat extends BaseHeapFileStat {
     public final Int32  st_flags = new Int32();
     public final Int32  st_gen = new Int32();
     public final Int32  st_lspare = new Int32();
-    public final Int64  st_qspare0 = new Int64();
-    public final Int64  st_qspare1 = new Int64();
+    public final Int64[] st_qspare = array(new Int64[2]);
     
     public MacOSHeapFileStat() {
         this(null);