diff --git a/ivar.h b/ivar.h
index 3145880..9f41af3 100644
--- a/ivar.h
+++ b/ivar.h
@@ -22,6 +22,10 @@ struct objc_ivar
 	 * offset from the object pointer.
 	 */
 	int        *offset;
+	/**
+	 * The size of this ivar.  Note that the current ABI limits ivars to 4GB.
+	 */
+	uint32_t    size;
 	/**
 	 * Flags for this instance variable.
 	 */