function book_admin_edit_validate

7.x book.admin.inc book_admin_edit_validate($form, &$form_state)
6.x book.admin.inc book_admin_edit_validate($form, &$form_state)

Check that the book has not been changed while using the form.

See also

book_admin_edit()

File

drupal-6.x/modules/book/book.admin.inc, line 87
Admin page callbacks for the book module.

Code

function book_admin_edit_validate($form, &$form_state) {
  if ($form_state['values']['tree_hash'] != $form_state['values']['tree_current_hash']) {
    form_set_error('', t('This book has been modified by another user, the changes could not be saved.'));
    $form_state['rebuild'] = TRUE;
  }
}