On Wednesday, April 9, 2025 at 06:54:34 PM EDT, Jeremy Drake via Cygwin <cygwin@cygwin.com> wrote:
> The recent issue with pthread_atfork handlers reminded me of a scenario > that I know glibc handles, but it seems that Cygwin does not. Test case: <... code that loads a shared lib, registers some functions in shared lib with pthread_atfork(), unloads the shared lib, and crashes on fork...> Calling functions in an unloaded library should result in undefined behavior. However, further investigation reveals that the Linux pthread_atfork() registered functions are not being called and POSIX does not proved a mechanism for un-registering these functions. Note: pthread_atfork() is not bumping the ref count on the shared lib--those functions are definitely unavailable after the dlclose() In the Cygwin version, calling the functions in the unloaded library when the fork happens causes the crash. This seems to be a bug with fork(), if it is a bug at all. Kevin -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation: https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
