'NPP_Destroy' behavior for 'NPSavedData' under Firefox 5.x?

As state

https://developer.mozilla.org/en/NPP_Destroy

second argument of 'NPP_Destroy' is data to save between plug-in
instances.

As I does not save any data I write:

NPError NPP_Destroy(NPP instance, NPSavedData **save)
{
     if (scriptableObj)
         npnfuncs->releaseobject(scriptableObj);
     scriptableObj = NULL;
     /* Don't share any data between plug-in instances. */
     *save = NULL;
     return NPERR_NO_ERROR;
}

With Firefox 5.x I get plug-in crashing because of NULL value for
'save' arg.

So I change code to

     if (!save)
         *save = NULL;

What is the right solution?