Removal of select() support from v4.0.x

Arran Cudbard-Bell a.cudbardb at
Sun Oct 9 21:19:36 CEST 2016

Support for select() has been removed from the v4.0.x branch.

For *BSD (and OSX) users, this should have no noticeable impact, for Linux users, there's now an additional hard dependency on libkqueue; a compatibility library that wraps epoll to provide a kqueuelike interface.

select() has serious scalability problems with more than a few hundred file descriptors, and as part of the re-architecture may involve switching to a hybrid unconnected/connected UDP socket system, the performance impact of continuing to use select() on Linux would have been too great.


Arran Cudbard-Bell <a.cudbardb at>
FreeRADIUS Development Team

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