diff --git a/server/gen_test_char.c b/server/gen_test_char.c
index c0d0903..cf7b0f8 100644
--- a/server/gen_test_char.c
+++ b/server/gen_test_char.c
@@ -120,8 +120,8 @@
          * XXX: With luck, isascii behaves sensibly on EBCDIC platforms
          *      and insists on chars that correspond to ASCII equivilants
          */
-        if (apr_iscntrl(c) || strchr(" \t()<>@,;:\\\"/[]?={}", c))
-                           || !apr_isascii(c)) {
+        if (!c || apr_iscntrl(c) || strchr(" \t()<>@,;:\\\"/[]?={}", c))
+                                 || !apr_isascii(c)) {
             flags |= T_HTTP_TOKEN_STOP;
         }