.. efun:: mixed * tls_check_certificate(object obj)
  mixed * tls_check_certificate(object obj, int extra)
  :experimental:

  Checks the certificate of the secured connection bound to :arg:`obj` (default is the current object). An error is thrown if :arg:`obj` is not interactive or TLS is not available.

  An error is also thrown if :arg:`obj` doesn't have a secure connection up and running.

  Otherwise, the result is an array with these values:

  .. todo:: needs broad structural revision, in theory the below should also use :manpage:`verify(1)`?

    int [0]   : Result code of SSL_get_verify_result (see 'man 1 verify' subsection DIAGNOSTICS for possible values).
    array [1] : Array with 3*n entries of extra x509 data. Structure is:
                  3*i    : numerical form of object name,
                           e.g. "2.5.4.3"
                  3*i + 1: long or short name if available,
                           e.g. "commonName"
                  3*i + 2: value
    array [2] : If :arg:`extra` is set: array with 3*n entries of x509 extension data data structure is:
                  3*i    : numerical form of extension name
                  3*i + 1: long or short name of extension
                           name if available
                  3*i + 2: array of strings with the data
                           structure of [1]

  .. note:: An X509 certificate can have more than one object with the same name.

  :history 3.3.672/3.2.11 introduced:
  :history 3.3.711/3.2.12 changed: modified the behaviour to return the low-level API result value, and to throw an error if the connection is not secure.

  .. seealso:: :efun:`tls_init_connection`, :efun:`tls_deinit_connection`, :efun:`tls_error`, :efun:`tls_query_connection_state`, :efun:`tls_query_connection_info`, :efun:`tls_available`, :efun:`tls_refresh_certs`, mudlib/psyc-tls.c