title: Equivalent of "Invalidate Rect" / "WM_PAINT" in X11
body: <p>I'm Porting some code from Windows to XLib.  In the windows code, I can force a redraw by calling <code>InvalidateRect</code> and then handling the corresponding <code>WM_PAINT</code> message.  However, I am having trouble finding out how to do this in X11/XLib.  I see there is an <code>Expose</code> message but not sure if that is the same thing.</p>
  
  <p>If it matters, I need to do this to force the window to render at a certain frame rate for an OpenGL based program.</p>