title: X11 Wait for and Get Clipboard Text
body: <p>I have to monitor the X11 Clipboard.</p>
  
  <p>For the moment, I request the ClipBoard Selection each 5 seconds, then I hash the text returned from clipboard and I compare it with the hash calculate from the last check. If hash are not the same, I analysis the text content and do some stuff...</p>
  
  <p>I don't like my method. I'm from Windows, and with the winapi, it is the kernel that notify your program when the clipboard has changed, and it's more efficient!</p>
  
  <p>I just want to know if it is possible that X11 can notify your program as winapi when the clipboard has changed ? What is the more efficient way to check clipboard modifications with X11 ?</p>