diff --git a/hardware.h b/hardware.h
index 2693e3b..8168d9c 100644
--- a/hardware.h
+++ b/hardware.h
@@ -14,7 +14,8 @@
 // Implements the real interface with the hardware.
 class Hardware : public HardwareInterface {
  public:
-  Hardware() {}
+  Hardware();
+  virtual ~Hardware();
 
   // HardwareInterface methods.
   virtual const std::string BootKernelDevice();