https://bugs.openldap.org/show_bug.cgi?id=10306

Issue ID: 10306 Summary: epoll, kqueue etc. are not used when cross compiling Product: OpenLDAP Version: 2.6.9 Hardware: All OS: All Status: UNCONFIRMED Keywords: needs_review Severity: normal Priority: --- Component: build Assignee: bugs@openldap.org Reporter: hi@alyssa.is Target Milestone: ---

OpenLDAP's build system relies on running test programs to see whether epoll or kqueue are available, after checking the headers are available. When cross compiling, test programs can't be run, and even if they could, they wouldn't produce useful results because they'd be testing the build machine. Running test programs like this isn't even a great idea for native builds, because the package is still quite likely to end up running on a different machine than it was built for — think about distro packages.

This means that cross-compiled OpenLDAP ends up using select, even though it could almost certainly use epoll or kqueue.

The best thing to do for this sort of thing is to check at runtime whether the epoll/kqueue/whatever is available, and fall back if not, but this would probably be hard to implement in OpenLDAP. Other, easier, things that could be done to improve the situation would be:

• Assume that epoll/kqueue are available if the headers are. It's very unlikely nowadays that a system with the headers won't actually have the API available. • If the AC_RUN_IFELSE checks are staying, make sure that they're all overridabel with configure flags or at least AC_CACHE_CHECK.

There are also uses of AC_RUN_IFELSE for pthreads, which presumably have the same problem.