CRYPTO_EX_INDEX_ENGINE
if (!CRYPTO_new_ex_data(CRYPTO_EX_INDEX_ENGINE, ret, &ret->ex_data)) {
CRYPTO_free_ex_data(CRYPTO_EX_INDEX_ENGINE, e, &e->ex_data);
CRYPTO_get_ex_new_index(CRYPTO_EX_INDEX_ENGINE, l, p, newf, dupf, freef)