title: Is it possible to retrieve the value of custom fields defined in a plugin in Wordpress?
body: <p>I want to modify a WordPress plugin which does not work properly.
  That is, </p>
  
  <pre><code>function append_query_string($url) {
    global $post;
    if ( get_post_meta($post-&gt;ID, 'inm_la_title_url', true) ) {
      if ( get_post_meta($post-&gt;ID, 'inm_la_new', true) ) {
        $link = get_post_meta($post-&gt;ID, 'inm_la_title_url', true) . '" target="_blank';
      } else {
        $link = get_post_meta($post-&gt;ID, 'inm_la_title_url', true);
      }
    } else {
      $link = $url;
    }
    return $link;
  }
  </code></pre>
  
  <p>The plugin file contains the above code. But it has an issue and I want to use the custom field "inm_la_new" defined within this plugin.</p>
  
  <p>I tried to use the following code in the index.php file:</p>
  
  <pre><code>&lt;?php
  if ( get_post_meta($post-&gt;ID, 'inm_la_new', true) ) { 
    echo '" target="_blank'; 
  } 
  ?&gt;
  </code></pre>
  
  <p>However, it does not work in the index.php file. I think it's because the "inm_la_new" field is defined within the plugin not within the theme's functions file. Is there a way to retrieve the custom field defined in a plugin not in the theme's functions file?</p>
  
  <p>Thank you.</p>