@deftypefun {int} {gnutls_x509_crt_set_proxy} (gnutls_x509_crt_t @var{crt}, int @var{pathLenConstraint}, const char * @var{policyLanguage}, const char * @var{policy}, size_t @var{sizeof_policy})
@var{crt}: a certificate of type @code{gnutls_x509_crt_t} 

@var{pathLenConstraint}: non-negative error codes indicate maximum length of path,
and negative error codes indicate that the pathLenConstraints field should
not be present.

@var{policyLanguage}: OID describing the language of  @code{policy} .

@var{policy}: uint8_t byte array with policy language, can be @code{NULL} 

@var{sizeof_policy}: size of  @code{policy} .

This function will set the proxyCertInfo extension.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, otherwise a
negative error value.
@end deftypefun