Method net_send_error_packet

sql/protocol.cc:411–476

*/

bool Protocol::net_send_error_packet(THD *thd, uint sql_errno, const char *err,
                                     const char* sqlstate)
{
  NET *net= &thd->net;
  uint length;
  /*
    buff[]: sql_errno:2 + ('#':1 + SQLSTATE_LENGTH:5) + MYSQL_ERRMSG_SIZE:512
  */
  uint error;
  char converted_err[MYSQL_ERRMSG_SIZE];
  char buff[2+1+SQLSTATE_LENGTH+MYSQL_ERRMSG_SIZE], *pos;
  my_bool ret;
  uint8 save_compress;
  DBUG_ENTER("Protocol::send_error_packet");

  if (net->vio == 0)
  {
    if (thd->bootstrap)
    {
      /* In bootstrap it's ok to print on stderr */
      fprintf(stderr,"ERROR: %d  %s\n",sql_errno,err);
    }
    DBUG_RETURN(FALSE);
  }

  int2store(buff,sql_errno);
  pos= buff+2;
  if (thd->client_capabilities & CLIENT_PROTOCOL_41)
  {
    /* The first # is to make the protocol backward compatible */
    buff[2]= '#';
    pos= strmov(buff+3, sqlstate);
  }

  convert_error_message(converted_err, sizeof(converted_err),
                        thd->variables.character_set_results,
                        err, strlen(err), system_charset_info, &error);
  /* Converted error message is always null-terminated. */
  length= (uint) (strmake(pos, converted_err, MYSQL_ERRMSG_SIZE - 1) - buff);

  /*
    Ensure that errors are not compressed. This is to ensure we can
    detect out of bands error messages in the client
  */
  if ((save_compress= net->compress))
    net->compress= 2;

  /*
    Sometimes, we send errors "out-of-band", e.g ER_CONNECTION_KILLED
    on an idle connection. The current protocol "sequence number" is 0,
    however some client drivers would however always   expect packets
    coming from server to have seq_no > 0, due to missing awareness
    of "out-of-band" operations. Make these clients happy.
  */
  if (!net->pkt_nr &&
      (sql_errno == ER_CONNECTION_KILLED || sql_errno == ER_SERVER_SHUTDOWN ||
       sql_errno == ER_QUERY_INTERRUPTED))
  {