From the docs - SIGALRM or another thread calling run. If these cases arent relevant, could you post an example of the unrelated code? On Fri, 18 Feb 2005 12:16:41 +0900, Sam Roberts <sroberts / uniserve.com> wrote: > Can anybody give me any hints as to what I should be looking for? What > can cause sleep(0) to wake up? > > I've got a thread that does > > loop do > sleep(delay) > > ... do stuff, then set delay to 0 because there is no more work ... > > delay = 0 > end > > And my loop is busy looping, sleep just won't! > > Whether it does or not is triggered by changes in what appear to me to > be completely unrelated code. I'm mystified. > > Thanks, > Sam > > -- spooq