present in the passed const PKCS8_PRIV_KEY_INFO structure <b>p8</b>.</p>

<p>PKCS8_pkey_add1_attr() adds a constructed X509_ATTRIBUTE <b>attr</b> to the existing PKCS8_PRIV_KEY_INFO structure <b>p8</b>.</p>

<p>PKCS8_pkey_add1_attr_by_NID() and PKCS8_pkey_add1_attr_by_OBJ() construct a new X509_ATTRIBUTE from the passed arguments and add it to the existing PKCS8_PRIV_KEY_INFO structure <b>p8</b>.</p>

<h1 id="RETURN-VALUES">RETURN VALUES</h1>

<p>PKCS8_pkey_add1_attr(), PKCS8_pkey_add1_attr_by_NID(), and PK