Need help!!!

Electboy · 07-12-2003, 02:26 PM

include <linux/module.h>
include <linux/kernel.h>

but error happened when i used printk() : like as "need library for printk()"
Any one has idea ?

TheLinuxDuck · 07-12-2003, 02:40 PM

Make sure that the include lines are as follows:

Code:

#include <linux/module.h>
#include <linux/kernel.h>

The #'s are important!

Also, there might be some libraries required to link in with your binary, since you're doing kernel stuff.. I really have no clue, since I've never done anything with the kernel. You might post the command you gave when compiling the source, and the error messages returned.

Electboy · 07-12-2003, 02:47 PM

Yes...i typed without "#" in my question. Any else about my problem?

kev82 · 07-12-2003, 02:50 PM

can you post your code, the command you used to compile, and the error it gave.

stupid question: you are only compiling and not linking the module arnt you? modules are linked at runtime by insmod so you must specify the -c option to gcc

TheLinuxDuck · 07-12-2003, 02:50 PM

What command did you use to compile the binary? What error messages did it return? Can you post them exactly?

Electboy · 07-13-2003, 12:13 PM

#include <linux/module.h>
#include <linux/kernel.h>
int init_module(void)
{
printk("<1>Hello world 1.\n");
return 0;}
void cleanup_module(void)
{
printk(KERN_ALERT "Goodbye world 1.\n");
}

That is my code.

kev82 · 07-13-2003, 01:42 PM

Quote:

can you post your code, the command you used to compile, and the error it gave

the command you used to compile would be good as would the error you get. i can compile your code(or rather peter salzman's) with no problem

Electboy · 07-13-2003, 01:49 PM

what kernel and Linux are u using ? mine is 2.4.20, Redhat 9. The command is
gcc -c -O2 -Wall -isystem /lib/modules/`uname -r`/build/include -D__KERNEL__ -DMODULE hello.o hello.c

kev82 · 07-13-2003, 01:57 PM

i have compiled it with kernel 2.4.19, my system is totally compiled from source.

i used the following command:
gcc -c -O2 -D__KERNEL__ -DMODULE -isystem /lib/modules/2.4.19/build/include/ mod.c

how about sharing the error you got with me?

Electboy · 07-13-2003, 02:09 PM

thank you kev82. Please open the kernel.h and search "printk" or "KERN_ALERT".

kev82 · 07-13-2003, 02:23 PM

both are defined

Electboy · 07-13-2003, 02:27 PM

OH really? but they are not defined in my kernel.h, kernel 2.4.20

kev82 · 07-13-2003, 02:33 PM

ive checked a machine running 2.4.20 both are defined in its kernel.h, most likely when you installed you or the installer neglected to install the appropriate files for kernel development, someone on a red hat forum might be able to help you with this but ive never used it so i dont know.

Electboy · 07-13-2003, 03:07 PM

Thank you all your help kev82. I think i will have to recompile my kernel