y) using OID <i>nid</i> and criticality <i>crit</i> according to <i>flags</i>.</p>

<p>X509V3_EXT_d2i() attempts to decode the ASN.1 data contained in extension <i>ext</i> and returns a pointer to an extension specific structure or NULL if the extension could not be decoded (invalid syntax or not supported).</p>

<p>X509V3_EXT_i2d() encodes the extension specific structure <i>ext_struc</i> with OID <i>ext_nid</i> and criticality <i>crit</i>.</p>

<p>X509_get_ext_d2i() and X509_add1_ext_i2d() operate on the 