diff --git a/include/proto/vars.h b/include/proto/vars.h
index de0987d..8414baa 100644
--- a/include/proto/vars.h
+++ b/include/proto/vars.h
@@ -7,6 +7,7 @@
 void vars_prune(struct vars *vars, struct session *sess, struct stream *strm);
 void vars_prune_per_sess(struct vars *vars);
 int vars_get_by_name(const char *name, size_t len, struct sample *smp);
+void vars_set_by_name_ifexist(const char *name, size_t len, struct sample *smp);
 void vars_set_by_name(const char *name, size_t len, struct sample *smp);
 int vars_get_by_desc(const struct var_desc *var_desc, struct sample *smp);
 int vars_check_arg(struct arg *arg, char **err);