Re: [PATCH 1/2] UNREACHABLE() macro

From: Roland McGrath
Date: Fri Sep 11 2009 - 17:56:41 EST


> That's a bit of a mouthful. Did you consider a runtime probe with
> scripts/Kbuild.include's try-run, cc-option, etc?

I did not see any precedent in the sources for using those to test for
features by compiling particular test sources (i.e. in autoconf style).
I just followed the model I saw. Those methods seem sufficiently costly
to make it a little questionable to pile on too many more that get
repeated all the time by make, so I just was not opening that can of worms.

As has been mentioned:

#if __GNUC_MINOR__ > 4

is a sufficient test for the long run. People using Fedora gcc-4.4 will
not mind applying a trivial kernel patch to get the benefits sooner.


Thanks,
Roland
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