title: Is there any way to check already preload libraries in psql or command line?
body: <p>In conf we added the following line:</p>
  <pre><code>shared_preload_libraries = 'passwordcheck'
  </code></pre>
  <p>After restart postgres, password check is supposed to take effect, and I can test by creating a simple password for the new role. My question is:</p>
  <p>Is there any way to list preloaded (enabled) libraries, or show this lib has been successfully loaded?</p>