diff --git a/control/argument.cpp b/control/argument.cpp
index d9b832d..e014453 100644
--- a/control/argument.cpp
+++ b/control/argument.cpp
@@ -33,7 +33,7 @@
         if ((option == '?') || (option == 'h'))
         {
             usage(argv);
-            exit(-1);
+            exit(1);
         }
 
         auto i = &options[0];