[Python-bugs-list] PyOS_AfterFork (PR#392)
Thu, 6 Jul 2000 01:52:32 -0400 (EDT)
> In posixmodule.c:posix_fork, the function PyOS_AfterFork is called for
> both the parent and the child, despite the docs stating that it should
> be called in the new (child) process.
> This causes problems in the parent since the forking thread becomes the
> main thread according to the signal module.
> e.g. the following program fails with the frustrating message:
> "ValueError: signal only works in main thread"
> import os, signal, threading
> def foo():
> pid = os.fork()
> if pid:
> os.wait(pid, 0)
> def handler(signo, frame):
> def main():
> t = threading.Thread(target=foo)
> t.join() # optional
> signal.signal(signal.SIGTERM, handler)
Yech! You're right. The code I wrote to call PyOS_AfterFork()
incorrectly assumed only the main thread would fork.
Fred: your fix is almost right -- there's a second call to
PyOS_AfterFork() in posixmodule.c (in forkpty()) that needs similar
--Guido van Rossum (home page: http://dinsdale.python.org/~guido/)