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Re: [PATCH 07/24] Remove NetBSD's system headers. We'll use the system-provided ones, which are up to date.

  • To: Manuel Bouyer <bouyer@xxxxxxxxxxxxxxx>
  • From: Roger Pau Monné <roger.pau@xxxxxxxxxx>
  • Date: Mon, 4 Jan 2021 18:09:07 +0100
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On Mon, Jan 04, 2021 at 11:25:52AM +0100, Manuel Bouyer wrote:
> On Tue, Dec 29, 2020 at 12:46:38PM +0100, Roger Pau Monné wrote:
> > What would happen when a new device (or ioctl to and existing one) is
> > added?
> > 
> > You would then run into issues of newer versions of Xen not building on
> > older NetBSD systems, or would have to appropriately gate the newly
> > added code to only be built when the headers are available.
> I prefer to have the build fail if the system isn't new enough, than
> have it build and then fail to run. We already have version requirements
> for e.g. bug fixes.

We usually take a different approach for Linux and FreeBSD in
order to support all kernels: test if the new ioctl is available, or
else fallback to the old implementation. But this requires having the
new header even on old systems in order to have the ioctl definition
for the build, even if it's not implemented on the currently running

I guess you would have to use preprocessor conditionals in order to
keep the build on older versions when adding the new features.




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