Subject: Re: Use of opt_ headers
To: None <tech-kern@netbsd.org>
From: David Laight <david@l8s.co.uk>
List: tech-kern
Date: 08/28/2006 13:48:44
On Mon, Aug 28, 2006 at 01:42:26PM +0200, Quentin Garnier wrote:
> On Mon, Aug 28, 2006 at 04:21:53AM -0500, Peter Seebach wrote:
> [...]
> > What is the compelling reason to write two dozen or more different files,
> > rather than having a single "options.h" header that everyone includes?
> 
> Because if one changes, you get to recompile everything.  Thanks, but
> no.  config(1) takes very good care at not touching a file if it hasn't
> changed.

The other advantage is that if you know that an xxx.o doesn't depend
on a specific option, you can use the same object file in two kernels
that are compiled with the option changed.

For instance on might expect that largely the same objects could
be used for GENERIC.MP and GENERIC.ACPI.

If we can use the same object for many of tehkernels we can significantly
improve the build time for the i386 releasesGENERIC.ACPI.

If we can use the same object for many of the kernels we can significantly
improve the build time for the i386 releases

	David

-- 
David Laight: david@l8s.co.uk