CMS_signed_get_attr_by_NID
&& CMS_signed_get_attr_by_NID(si, NID_pkcs9_signingTime, -1) < 0) {
loc = CMS_signed_get_attr_by_NID(si, NID_pkcs9_signingTime, -1);
int CMS_signed_get_attr_by_NID(const CMS_SignerInfo *si, int nid,