I use red hat 9.0.


[root@xuwei tulip]# gcc -DMODVERSIONS -DMODULE -D__KERNEL__ -Wall -Wstrict-prototypes -O6 -c tulip.c
In file included from tulip.c:109:
/usr/include/linux/modversions.h:1:2: #error Modules should never use kernel-headers system headers,
/usr/include/linux/modversions.h:2:2: #error but rather headers from an appropriate kernel-source package.
/usr/include/linux/modversions.h:3:2: #error Change -I/usr/src/linux/include (or similar) to
/usr/include/linux/modversions.h:4:2: #error -I/lib/modules/$(uname -r)/build/include

/usr/include/linux/modversions.h:5:2: #error to build against the currently-running kernel.
In file included from /usr/include/linux/fs.h:23,
from /usr/include/linux/capability.h:17,
from /usr/include/linux/binfmts.h:5,
from /usr/include/linux/sched.h:9,
from tulip.c:118:
/usr/include/linux/string.h:8:2: warning: #warning Using kernel header in userland!
In file included from /usr/include/linux/sched.h:14,
from tulip.c:118:
/usr/include/linux/timex.h:173: field `time' has incomplete type
In file included from /usr/include/linux/bitops.h:69,
from /usr/include/asm/system.h:7,
from /usr/include/linux/sched.h:16,
from tulip.c:118:
/usr/include/asm/bitops.h:327:2: warning: #warning This includefile is not available on all architectures.
/usr/include/asm/bitops.h:328:2: warning: #warning Using kernel headers in userspace: atomicity not
[1]+ Stopped gcc -DMODVERSIONS -DMODULE -D__KERNEL__ -Wall -Wstrict-prototypes -O6 -c tulip.c
[root@xuwei tulip]#

why did this occur?
I had check the file versionmodule.h which was existed.