Don't crash when displaying help for formats with no options.

diff --git a/vecs.c b/vecs.c
index 5864f74c7d99b64696668584a9ad75e603398160..0f39461bfac303408a2270c73fe2a16c0909e95e 100644 (file)
--- a/vecs.c
+++ b/vecs.c
@@ -686,7 +686,7 @@ assign_option(const char *module, arglist_t *ap, const char *val)
 void
 disp_vec_options(const char *vecname, arglist_t *ap)
 {
-       for (ap = ap; ap->argstring; ap++) {
+       for (ap = ap; ap && ap->argstring; ap++) {
                if (*ap->argval && ap->argval) {
                        printf("options: module/option=value: %s/%s=\"%s\"", 
                                vecname, ap->argstring, *ap->argval);