Method cast_pluginvar

sql/sql_plugin.cc:318–318

                    st_plugin_int *p, st_mysql_sys_var *plugin_var_arg,
                    const char *substitute);
  sys_var_pluginvar *cast_pluginvar() override { return this; }
  uchar* real_value_ptr(THD *thd, enum_var_type type) const;
  TYPELIB* plugin_var_typelib(void) const;
  const uchar* do_value_ptr(THD *thd, enum_var_type type, const LEX_CSTRING *base) const;