On Thu, 3 Apr 2025, Johannes Schindelin wrote: > I still have a question that I would like to be answered in the commit > message, too: > > If `signal_arrived` is only initialized in `fixup_after_fork()` but user > callbacks that use this are called by `atforkchild()`, why did this not > trigger _all the time_ before your reordering of the calls?
Based on my recollections, Takashi probably knows better 1) there has to be a pthread_atfork child callback registered 2) this callback has to call raw_write 3) raw_write now calls cygwait (which is now reenterancy-safe due to other fallout from this) 4) cygwait allows signals to be processed, so needs the signal-handling stuff to be properly initialized. I'm guessing, if raw_write doesn't need to wait (ie, there's room in the pipe for the write) it doesn't hit the signal stuff. But I get your request for explaining the scenario in the commit message.
