Charles-François Natali added the comment: > Guido van Rossum added the comment: > > Actually, I think we're talking about the actual select() syscal not > returning when SIGCHLD is received and handled. Running the C-level handler > isn't enough, the syscall must return with EINTR so the Python handler can > run (which then writes a byte to the self-pipe to ensure select() returns, > but that seems too late).
I just realized the following: there's no need for EINTR to break out of select(), that's what the self-pipe is for: since the write-end is registered as wakeup FD, and the read-end is registered in the selector, when the C-level signal handler is executed, it writes to the wakeup FD, therefore the select() syscall should return with the read-end ready, or more likely fail with EINTR. And then, the Python-level signal handler should be executed (from the main loop), scheduling a callback, and re-trigerring a wakup through the self-pipe. If this doesn't work as-is, I only see two explanations: - the C-level signal handler doesn't get called, which seems impossible - the python-level signal handler doesn't get executed before the main loop re-enters select(), but since the new GIL signal handlers are called at each eval loop In short, I'm puzzled. I can tell why my patch should work, but I'm not sure why the current approach doesn't. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue19293> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
