added diagnostics

src/db/dbServiceIO.cpp

@@ -156,3 +156,18 @@ dbEventSubscription dbServiceIO::subscribe ( struct dbAddr &addr, dbSubscription
 
     return es;
 }
+
+void dbServiceIO::show ( unsigned level ) const
+{
+    this->mutex.lock ();
+    printf ( "dbServiceIO at %p\n", this );
+    if (level > 0u ) {
+        printf ( "\tevent call back cache location %p, and its size %lu\n", 
+            this->pEventCallbackCache, this->eventCallbackCacheSize );
+    }
+    if ( level > 1u ) {
+        this->mutex.show ( level - 2u );
+    }
+    this->mutex.unlock ();
+}
+