Making new variable for a theme function shows an error notice

Question

I am trying to make a new variable for a theme whose name is ntheme. I have defined the following function in template.php.

function ntheme_gnu_preprocess(&$variables) {
  $variables['disclaimer'] = t('Comments are unaythorized. The views expressed are those of the comment author.');
}

I used $disclaimer in the comment-wrapper.tpl.php template file.

<div id="comments" class="<?php print $classes; ?>"<?php print $attributes; ?>>
  <?php if ($content['comments'] && $node->type != 'forum'): ?>
    <?php print render($title_prefix); ?>
    <h2 class="title"><?php print t('Comments'); ?></h2>
    <?php print render($title_suffix); ?>
  <?php endif; ?>
  <?php print render($content['comments']); ?>
  <?php if ($content['comment_form']): ?>
    <h2 class="title comment-form"><?php print t('Add new comment'); ?></h2>
    <?php print render($content['comment_form']); ?>
  <?php endif; ?>
  <p><?php print $disclaimer; ?></p>
</div>

I get the following warning.

Notice: Undefined variable: disclaimer in include() (line 39 of C:\wamp\www\drupal\sites\all\themes\ntheme\templates\comment-wrapper.tpl.php).

What am I doing wrong?

Answer 1

You should use THEME_preprocess_comment_wrapper(&$variables) to alter comment wrapper variables.

Answer 2

Each template file has its own preprocess/process functions. If <theme> is the theme identifier for the theme function, then <module_name>_preprocess_<theme>(), <theme_name>_preprocess_<theme>(), <module_name>_process_<theme>(), and <theme_name>_process_<theme>() are the function names for the preprocess/process functions.

In this case, ntheme_gnu_preprocess() would not be a preprocess function, since it doesn't follow the schema Drupal adoptes for preprocess/process functions: ntheme_gnu is not the short name of the theme.

ntheme_preprocess(&$variables, $hook) would be invoked, but for every theme function / theme template used from Drupal; if you need to use the preprocess function just for the comment-wrapper.tpl.php template file, then you should use ntheme_preprocess_comment_wrapper().