[PATCH] xfree86: Use SA_SIGINFO if available for SIGIO handlers

Mark Kettenis mark.kettenis at xs4all.nl
Tue Nov 10 12:15:07 PST 2009

> From: Adam Jackson <ajax at redhat.com>
> Date: Tue, 10 Nov 2009 15:03:31 -0500
> This one's slightly subtle, the fcntl(F_SETSIG) is required for ->si_fd
> to actually be filled in correctly, at least on Linux.  I know this area
> has been sensitive to platform variation in the past, so I'd appreciate
> a second look from Solaris / BSD / Hurd people.

Alas, OpenBSD doesn't have si_fd.  So if you really want to go this
route, you'll need to add an additional configure check for it.

> siginfo_t gives us the file descriptor that raised the signal directly,
> so we don't need to select() for it.  This gets evdev event processing
> down to exactly one syscall in the common case.

Is that an optimizition that's really worth the added complexity?

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