Function restore_ptr_backup

sql/sql_plugin.cc:4478–4482

On dlclose() we need to restore values of all symbols that we've modified in the DSO. The reason is - the DSO might not actually be unloaded, so on the next dlopen() these symbols will have old values, they won't be reinitialized. Perhaps, there can be many reason, why a DSO won't be unloaded. Strictly speaking, it's implementation defined whether to unload an unused DSO or to keep it

  state before dlclose().
*/
static void restore_ptr_backup(uint n, st_ptr_backup *backup)
{
  while (n--)
    (backup++)->restore();
}

/****************************************************************************
  thd specifics service, see include/mysql/service_thd_specifics.h