compat.linux.osrelease behavior

[Alexander Leidinger]

On Sun, 20 Sep 2009 08:30:17 +0200 Roman Divacky <rdivacky at freebsd.org>
wrote:


> On Sat, Sep 19, 2009 at 10:36:24PM +0200, Alexander Leidinger wrote:
> > On Fri, 18 Sep 2009 15:08:31 +0200 (CEST) Alexander Best
> > <alexbestms at math.uni-muenster.de> wrote:
> > 
> > 
> > > hi there,
> > > 
> > > i have a question regarding the behavior of
> > > compat.linux.osrelease. setting it to 2.4.2 sets linuxulator into
> > > 2.4 kernel-emulation and 2.6.16 sets it into 2.6 kernel-emulation
> > > right?
> > 
> > Sort of. 2.6.x set's 2.6 mode, and everything else is 2.4 mode. But
> > this is AFAIK only a semantic change of some functions. This does
> > not disable syscalls which are in 2.6 but not in 2.4.
> > 
> > > but what happens when compat.linux.osrelease gets set to a
> > > different value? ports/Updating entry 20071101 e.g. advises skype
> > > users to set compat.linux.osrelease to 2.4.20. does this trigger
> > > 2.6 kernel-emulation because 2.4.20 > 2.4.2 or are there more
> > > than two kernel-emulation layers inside the linuxulator??
> > 
> > It does not affect the kernel emulation. But the glibc will try to
> > use new syscalls.
> 
> actually it does change how the kernel emulation works. grep for
> linux_use26()

I don't find the place where the behavior is changed when 2.4.20 is
set... I only see a change when it is set to 2.6.x.

Bye,
Alexander.