title: `static` keyword inside function?
body: <p>I was looking at the source for Drupal 7, and I found some things I hadn't seen before. I did some initial looking in the php manual, but it didn't explain these examples. </p>
  
  <p>What does the keyword <code>static</code> do to a variable inside a function?</p>
  
  <pre><code>function module_load_all($bootstrap = FALSE) {
      static $has_run = FALSE
  </code></pre>