@deftypefun {unsigned} {gnutls_x509_crt_check_key_purpose} (gnutls_x509_crt_t @var{cert}, const char * @var{purpose}, unsigned @var{flags})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  type

@var{purpose}: a key purpose OID (e.g., @code{GNUTLS_KP_CODE_SIGNING} )

@var{flags}: zero or @code{GNUTLS_KP_FLAG_DISALLOW_ANY} 

This function will check whether the given certificate matches
the provided key purpose. If  @code{flags} contains @code{GNUTLS_KP_FLAG_ALLOW_ANY}  then
it a certificate marked for any purpose will not match.

@strong{Returns:} zero if the key purpose doesn't match, and non-zero otherwise.

@strong{Since:} 3.5.6
@end deftypefun