Subject: Re: Syscall and syscall versioning documentation
To: Thor Lancelot Simon <tls@rek.tjls.com>
From: Pavel Cahyna <pavel@NetBSD.org>
List: tech-kern
Date: 11/22/2006 13:21:35
On Tue, Nov 21, 2006 at 08:18:35PM -0500, Thor Lancelot Simon wrote:
> On Tue, Nov 21, 2006 at 11:16:24PM +0100, Pavel Cahyna wrote:
> > On Tue, Nov 21, 2006 at 06:15:37PM +0000, Christos Zoulas wrote:
> > 
> > > 3. In 3.2.6, mention that we usually implement the older version of the
> > >    syscall in libc so that we can provide binary compatibility for
> > >    dynamically linked libraries without needing the kernel support.
> > 
> > This was already there.
> 
> I think this is a highly misleading explanation anyway.  We implement
> the older version of the syscall in libc because we are afraid to bump
> the libc major number, and thus we *must* provide every function that
> was ever present there.

I think this is not true. You explain why do we have to provide the
function in libc, but not why is it implemented using the new syscall.
It could be also done as a wrapper around the compat syscall.

Pavel