On Sun, Nov 14, 2021 at 4:42 AM Mladen Gogala via Python-list <python-list@python.org> wrote: > > On Thu, 11 Nov 2021 17:22:15 +1100, Chris Angelico wrote: > > > Threads aren't the point here - signals happen immediately. > > Actually, signals are not delivered immediately. Signals are delivered > the next time the process gets its turn on CPU. The process scheduler > will make process runnable and the process will check for any pending > signals first and will execute the handler. It is possible to have > several SIGINT signals pending, for instance when I nervously press ctrl- > C several times. However, signals are not processed as a part of the > normal flow of the process and are processed sequentially.. When the > process finds a pending signal, it executes the registered signal > handler. It's always the same signal handler, unless signal handler is > changed within the signal handler. After the signals are delivered, the > process continues its normal operation until its CPU quantum expires or > until initiates a synchronous I/O operation, as is the case with all > normal read operations. > BTW, that's the case on both Unix/Linux systems and Windows systems. >
Maybe at the C level, but none of that happens in Python :) There's a very very small signal handler in CPython that just sets a flag and then handles things separately. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
