On Tue, 16 Dec 2008, Luis Henriques wrote:
> Hi,
>
> On Tue, Dec 16, 2008 at 12:18:55PM -0500, Robert P. J. Day wrote:
> >
> > i don't have access to a test system at the moment, so i'll
> > embarrass myself by just asking:
> >
> > when i'm writing a loadable module to be built out-of-tree, how do i
> > properly configure the header file search path so i can include
> > locally-written header files in my module?
> >
> > say i have a module source file that needs to include the relative
> > header file "../include/header.h". i'm fairly sure i can just write:
> >
> > #include "../include/header.h"
> >
> > and that will work with no additional configuration. (this suggests
> > that the kernel module build process automatically adds the source
> > directory to its header file search path, correct? otherwise, the
> > above couldn't possibly work.)
> >
> > but what if i want to just say:
> >
> > #include "header.h"
> >
> > what's the proper way to invoke the kernel source tree Makefile to add
> > the header file directory to the header file search path? thanks. i
> > realize this is a simple question, i just don't have access to my work
> > system at the moment to check it myself.
>
> I believe the standard (recommended) way of doing this is using the EXTRA_CFLAGS
> variable in your makefile. Adding:
>
> EXTRA_CFLAGS := -I../include
>
> should be enough for your code to work.
>
> Take a look at Documentation/kbuild/modules.txt file ;)
that's probably what i'm looking for -- i'm hoping it works as far
back as 2.6.10 since i'm sort of stuck with that for the time being.
i'll take a look at the top-level Makefile and the scripts/
sub-Makefiles to see how EXTRA_CFLAGS is used there. my first warning
would be if that variable is simply assigned from scratch rather than
being enhanced with "+=". thanks for the pointer.
rday
--
========================================================================
Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry:
Have classroom, will lecture.
http://crashcourse.ca Waterloo, Ontario, CANADA
========================================================================
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