Subject: Re: is obsolete?
To: walt <firstname.lastname@example.org>
From: Garrett D'Amore <email@example.com>
Date: 03/10/2006 09:57:01
> On Fri, 2006-03-10 at 11:00 -0500, Chris Ross wrote:
>> On Mar 10, 2006, at 9:16 AM, walt wrote:
>>> Thanks. This is my real problem: building libgtop2 from pkgsrc:
>>> _KERNEL is indeed defined in the source code of libgtop2 which is
>>> why msg.h wants to include systm.h. But systm.h has been deleted
>>> by postinstall, which doesn't seem to make sense.
>> Any software that defines _KERNEL (because it needs internal
>> interface stuff) needs to include files from /sys (or /usr/src/sys, or
>> the like), rather than /usr/include. The stuff in /usr/include is
>> for user-land software, not kernel software.
> I've always been confused about this subject -- still am. Maybe you
> can clear this up for me.
> For example, take this snippet from /usr/include/sys/msg.h:
> #include <sys/systm.h>
> Given that _KERNEL is defined (as it is in libgtop2) what is
> cpp supposed to do with that line? How/why would it look anywhere
> but /usr/include? (I understand that the <> brackets mean that
> the header is to be found in /usr/include -- am I mistaken about
The short answer is that it is *wrong* for gtop to #define _KERNEL.
That macro should *only* be used by kernel software.
If gtop needs some definition that is protected by _KERNEL, then someone
needs to figure out a proper way to export it to userland processes
without requiring this macro.
Ideally this stuff shouldn't be groveling around in kmem anyway. :-)
Garrett D'Amore, Principal Software Engineer
Tadpole Computer / Computing Technologies Division,
General Dynamics C4 Systems
Phone: 951 325-2134 Fax: 951 325-2191