HACKING

This file describes some hacking techniques that are particular
for the Open Inventor GUI toolkit family.

Be sure to check Coin/HACKING for Coin-specific tricks and more
generic information, plus the src/Inventor/Xt/common/HACKING file for
some hints common to all GUI interface toolkits.


0 Debugging X11 Window System Protocol Errors
=============================================

  Because X11 does asynchronous client-server communication, it can be
  hard to debug: in the default setup, you can't simply set up
  breakpoints and get a sensible backtrace. So for information on how
  to debug X11 problems, see this link for a very thorough
  walk-through of the issues one should know about:

        <URL:http://www.rahul.net/kenton/perrors.html>


  In SoXt, we've written some support code to automatically call

        XSynchronize(<display>,True)

  ..if the SOXT_XSYNC environment variable is set to "1".

  So to debug X11 errors in SoXt, set SOXT_XSYNC=1 in your
  environment, then load your SoXt-based application in a debugger,
  set a breakpoint on main(), execute the application, then set a
  breakpoint on _XError, then continue execution. When the application
  now fails, you should be able to get a sensible backtrace.