diff --git a/macosx/iphone/main_master.mm b/macosx/iphone/main_master.mm
index 00bc73a9..00c3bff7 100644
--- a/macosx/iphone/main_master.mm
+++ b/macosx/iphone/main_master.mm
@@ -78,8 +78,13 @@ int main(int argc, char *argv[]) {
             memcpy(audio_output_buffer[i], audio_input_buffer[i], buffer_size * sizeof(float));
         }
         
-        jack_net_master_send(net, result.audio_output, audio_output_buffer, 0, NULL);
-        jack_net_master_recv(net, result.audio_input, audio_input_buffer, 0, NULL);
+        if (jack_net_master_send(net, result.audio_output, audio_output_buffer, 0, NULL) < 0) {
+            break;
+        }
+        
+        if (jack_net_master_recv(net, result.audio_input, audio_input_buffer, 0, NULL) < 0) {
+            break;
+        }
         usleep(wait_usec);
 	};
     
@@ -95,7 +100,6 @@ int main(int argc, char *argv[]) {
           free(audio_output_buffer[i]);
     }
     free(audio_output_buffer);
-
    
     //int retVal = UIApplicationMain(argc, argv, nil, nil);
     [pool release];