* @return
* 0 on success (*result must be set), or -errno on error (*result
* is undefined).
*/
typedef int (*ec_node_expr_eval_var_t)(
void **result, void *userctx,
* @return
* 0 on success (*result must be set), or -errno on error (*result
* is undefined).
*/
typedef int (*ec_node_expr_eval_var_t)(
void **result, void *userctx,