Re: Another thing about Xlib

[Jeffrey B. Siegal]

This is evil.  You can not call Xlib from a signal handler.  The
overhead of blocking signals during critical sections of Xlib would be
way too high (typical Xlib calls involve zero system calls).

The fix is to restructure the application so that it does not call Xlib
from signal handlers.  Recent versions of Xlib *can* be called from
multiple threads, but not signal handlers.  

See http://www.faqs.org/faqs/x-faq/part7/section-14.html