diff --git a/networktransport.cpp b/networktransport.cpp
index 8cea651..f97268f 100644
--- a/networktransport.cpp
+++ b/networktransport.cpp
@@ -85,15 +85,15 @@ void Transport<MyState, RemoteState>::recv( void )
       if ( i->num > new_state.num ) {
 	received_states.insert( i, new_state );
 	if ( verbose ) {
-	  fprintf( stderr, "[%d] Received OUT-OF-ORDER state %d [ack %d]\n",
-		   (int)timestamp() % 100000, (int)new_state.num, (int)inst.ack_num() );
+	  fprintf( stderr, "[%u] Received OUT-OF-ORDER state %d [ack %d]\n",
+		   (unsigned int)(timestamp() % 100000), (int)new_state.num, (int)inst.ack_num() );
 	}
 	return;
       }
     }
     if ( verbose ) {
-      fprintf( stderr, "[%d] Received state %d [ack %d]\n",
-	       (int)timestamp() % 100000, (int)new_state.num, (int)inst.ack_num() );
+      fprintf( stderr, "[%u] Received state %d [ack %d]\n",
+	       (unsigned int)(timestamp() % 100000), (int)new_state.num, (int)inst.ack_num() );
     }
     received_states.push_back( new_state );
     sender.set_ack_num( received_states.back().num );
diff --git a/transportsender.cpp b/transportsender.cpp
index 6a69d8c..44ec541 100644
--- a/transportsender.cpp
+++ b/transportsender.cpp
@@ -248,8 +248,8 @@ void TransportSender<MyState>::send_in_fragments( string diff, uint64_t new_num
     connection->send( i->tostring() );
 
     if ( verbose ) {
-      fprintf( stderr, "[%d] Sent [%d=>%d] id %d, frag %d ack=%d, throwaway=%d, len=%d, frame rate=%.2f, timeout=%d\n",
-	       (int)(timestamp() % 100000), (int)inst.old_num(), (int)inst.new_num(), (int)i->id, (int)i->fragment_num,
+      fprintf( stderr, "[%u] Sent [%d=>%d] id %d, frag %d ack=%d, throwaway=%d, len=%d, frame rate=%.2f, timeout=%d\n",
+	       (unsigned int)(timestamp() % 100000), (int)inst.old_num(), (int)inst.new_num(), (int)i->id, (int)i->fragment_num,
 	       (int)inst.ack_num(), (int)inst.throwaway_num(), (int)i->contents.size(),
 	       1000.0 / (double)send_interval(),
 	       (int)connection->timeout() );