-extern int list_is_valid(const struct list *the_list);
-
-extern int enlist (struct list *the_list, const char *str);
-extern int enlist_unique (struct list *the_list, const char *str, int num_significant_chars);
-extern int enlist_unique_header (struct list *the_list, const char *name, const char *value);
-extern int enlist_first (struct list *the_list, const char *str);
-extern int list_append_list_unique(struct list *dest, const struct list *src);
-extern int list_duplicate (struct list *dest, const struct list *src);
+extern jb_err enlist (struct list *the_list, const char *str);
+extern jb_err enlist_unique (struct list *the_list, const char *str, size_t num_significant_chars);
+extern jb_err enlist_unique_header (struct list *the_list, const char *name, const char *value);
+extern jb_err enlist_first (struct list *the_list, const char *str);
+extern jb_err list_append_list_unique(struct list *dest, const struct list *src);
+extern jb_err list_duplicate (struct list *dest, const struct list *src);