it, void *ext_struc);

 void *X509_get_ext_d2i(const X509 *x, int nid, int *crit, int *idx);
 int X509_add1_ext_i2d(X509 *x, int nid, void *value, int crit,
                       unsigned long flags);

 void *X509_CRL_get_ext_d2i(const X509_CRL *crl, int nid, int *crit, int *idx);
 int X509_CRL_add1_ext_i2d(X509_CRL *crl, int nid, void *value, int crit,
                           unsigned long flags);

 void *X509_REVOKED_get_ext_d2i(const X509_REVOKED *r, int nid, int *crit, int *idx);
 int X509_REVOKED_a