diff --git a/libs/backends/portaudio/portaudio_backend.cc b/libs/backends/portaudio/portaudio_backend.cc
index 398347b8db..b7afb4c48d 100644
--- a/libs/backends/portaudio/portaudio_backend.cc
+++ b/libs/backends/portaudio/portaudio_backend.cc
@@ -1223,7 +1223,7 @@ PortAudioBackend::get_port_name (PortEngine::PortHandle port) const
 {
 	if (!valid_port (port)) {
 		DEBUG_PORTS("get_port_name: Invalid Port(s)\n");
-		return PortFlags (0);
+		return std::string ();
 	}
 	return static_cast<PamPort*>(port)->name ();
 }
@@ -1233,7 +1233,7 @@ PortAudioBackend::get_port_flags (PortEngine::PortHandle port) const
 {
 	if (!valid_port (port)) {
 		DEBUG_PORTS("get_port_flags: Invalid Port(s)\n");
-		return std::string ();
+		return PortFlags (0);
 	}
 	return static_cast<PamPort*>(port)->flags ();
 }