diff --git a/include/camera/CameraParameters.h b/include/camera/CameraParameters.h
index 6c6d0bc..a7568d7 100644
--- a/include/camera/CameraParameters.h
+++ b/include/camera/CameraParameters.h
@@ -228,6 +228,9 @@
     // Example value: "true". Read only.
     static const char KEY_SMOOTH_ZOOM_SUPPORTED[];
 
+    // Value for KEY_ZOOM_SUPPORTED or KEY_SMOOTH_ZOOM_SUPPORTED.
+    static const char TRUE[];
+
     // Values for white balance settings.
     static const char WHITE_BALANCE_AUTO[];
     static const char WHITE_BALANCE_INCANDESCENT[];