--- indent-2.2.10.old/man/texinfo2man.c
+++ indent-2.2.10/man/texinfo2man.c
@@ -253,6 +253,12 @@
     char buf[1024];
     int line_no = 0;
 
+    if (argc != 3)
+    {
+        fprintf (stderr, "Usage error\n");
+        exit (1);
+    }
+
     texinfoname = argv[2];
 
     in = fopen (argv[2], "r");