On Mon, Aug 18, 2014 at 8:33 PM, james <ja...@mansionfamily.plus.com> wrote: > Why not call it yourself, when you cancel?
Mainly because of reason 1. If the open() system call has already finished, then libeio is the only thing that knows what the file descriptor is. The calling code has no way of knowing what the file descriptor is, and thus no way to clean up the file descriptor. Furthermore, even if reason 1 does not hold, I still cannot safely call the callback myself, because of race conditions. The libeio thread might not have seen my cancellation flag (e.g. due to compiler optimizations, CPU instruction reordering, lack of memory barriers, etc) and might be about to call my callback. This will result in my callback being called twice. This can be solved my making callbacks idempotent, but - in line with reason 2 - it increases the complexity of the calling codebase by introducing new code paths. -- Phusion | Web Application deployment, scaling, and monitoring solutions Web: http://www.phusion.nl/ E-mail: i...@phusion.nl Chamber of commerce no: 08173483 (The Netherlands) _______________________________________________ libev mailing list libev@lists.schmorp.de http://lists.schmorp.de/cgi-bin/mailman/listinfo/libev
