diff --git a/Fonderie/fonderie.c b/Fonderie/fonderie.c
index a82a573..b949973 100644
--- a/Fonderie/fonderie.c
+++ b/Fonderie/fonderie.c
@@ -229,6 +229,7 @@ while ((opt = getopt(argc, argv, "B:E:F:ghI:LO:T:vw:x:")) != -1) {
 				break;
 		case 'v':	verbosity++;
 				break;
+		default:	exit(1);
 		}
 	}
 
diff --git a/Fonderie/interpolator.c b/Fonderie/interpolator.c
index 6436eaf..86ec78c 100644
--- a/Fonderie/interpolator.c
+++ b/Fonderie/interpolator.c
@@ -274,6 +274,7 @@ while ((opt = getopt(argc, argv, "E:F:hLnS:v")) != -1) {
 		case 'S':	sort = atoi(optarg);	break;
 		case 'v':	verbosity++;		break;
 		case 'n':	negative = 1;		break;
+		default:	exit(1);
 		}
 	}