title: How to run a hook action when header load in wordpress blog?
body: <p>Am woking on an error plugin.
  I want to generate some error or success msgs when header loads in WordPress blog site.</p>
  
  <p>like as:</p>
  
  <pre><code>if(is header load)
  {
    //run a action hook here
    //print success or error msgs through hook function
  }
  </code></pre>
  
  <p>suggest a hook action to display msgs when header load.</p>