diff --git a/pgrep.c b/pgrep.c
index fed70b9..5b39c0c 100644
--- a/pgrep.c
+++ b/pgrep.c
@@ -564,7 +564,7 @@ int signal_option(int *argc, char **argv)
 {
 	int sig;
 	int i = 1;
-	while (i < *argc) {
+	if (argc > 2 && argv[1][0] == '-') {
 		sig = signal_name_to_number(argv[i] + 1);
 		if (sig == -1 && isdigit(argv[1][1]))
 			sig = atoi(argv[1] + 1);