Hi

I want to build a driver for the linux kernel which uses header files not in the current directory.

== Dir tree looks like this

/foo/inc/myheader.h
/foo/driver/mydriver.c
/foo/driver/Makefile

== /driver/Makefile looks like this:

KERNELDIR=/usr/src/linux
TOPDIR=/foo
obj-m := mydriver.o

mydriver.o: mydriver.c ../inc/myheader.h
$(MAKE) -I $(TOPDIR)/inc -C $(KERNELDIR) M=`pwd` modules

== This will work until I add the following line in mydriver.c

#include <myheader.h>

At that point, it will complain that it can not find myheader.h

During compile, I see this:

make - I /foo/inc -C /usr/src/linux M=`pwd` modules
make [3] Entering Directory `/usr/src/linux'
CC [M] /foo/driver/mydriver.o
/foo/driver/mydriver.c:20:10: error: myheader.h: No such filer or directory

#include "inc/myheader.h"

Using <myheader.h> tells the compiler to look for the include in the standard include path. Putting it in quotes instead specifies a search relative to the directory you are compiling in.

#include "foo.h" does not work.
#include "inc/foo.h" also does not work.

Suggest : Move or copy 'myheader.h' to foo/driver/ ,
then it will sit in the same directory as 'mydriver.c'
and can be included with : #include "myheader.h"

" " is for a local file, < > is for a system file,
e.g. in /usr/include/ .

.....

i can't exactly provide you with a solution, because i'm looking in to these matters myself this time, still i think that if you haven't already looked there, there's some documentation at /usr/src/linux-`uname -r`/Documentation/kbuild/modules.txt

specially chapter 6 on include directories

#include "../inc/foo.h" -> it will work