diff --git a/include/proto/vars.h b/include/proto/vars.h
index 4c85825..9299b9f 100644
--- a/include/proto/vars.h
+++ b/include/proto/vars.h
@@ -8,6 +8,7 @@
 void vars_prune_per_sess(struct vars *vars);
 int vars_get_by_name(const char *name, size_t len, struct stream *strm, struct sample *smp);
 void vars_set_by_name(const char *name, size_t len, struct stream *strm, struct sample *smp);
+int vars_get_by_desc(const struct var_desc *var_desc, struct stream *strm, struct sample *smp);
 int vars_check_arg(struct arg *arg, char **err);
 
 #endif