title: Is there a way to have sphinx call a script or executable as a pre build task?
body: <p>I'm trying to stitch together doxygen and sphinx using breathe.</p>
  <p>breathe requires you generate doxygen xml output first though: <a href="https://breathe.readthedocs.io/en/latest/quickstart.html" rel="nofollow noreferrer">https://breathe.readthedocs.io/en/latest/quickstart.html</a></p>
  <p>I don't want to do this in a separate step. Can I just have <code>sphinx-build</code> execute <code>doxygen</code> for me on build? I just need it to run this command first with some args. Is this possible without having to write a custom sphinx plugin?</p>
  <h1>EDIT</h1>
  <p>This works</p>
  <pre><code># Need to sleep because sometimes doxygen doesnt finish writing files before sphinx runs 
  cwd = os.path.dirname(os.path.realpath(__file__))
  os.system('doxygen')
  time.sleep(3)
  </code></pre>