title: Qt creator, error message
body: <p>I am a little rusty with QT but I've had to use it for projects before. </p>
  
  <p>I was wondering if I could make a pop-up window, a small window with it's height/width disabled so the user can't expand it. It should also lock the screen until they press a button on this window.</p>
  
  <p>I could do all of this in a separate class, but I was wondering. Are there any built-in QT classes that have a little popup like this that I could just modify? I mean making a class just for an error message seems to me a little wasteful. I'm trying to keep the project small. </p>
  
  <p>But if a class is required to be made in order to accomplish this, that is fine. The only problem is I have no clue how to lock the application windows so that you have to do something one window before you can go back to the main application.</p>
  
  <p>I'm not asking for someone to type out all this code for me, just give me a link or something. I've looked for it but I couldn't find it. Cheers.</p>