Re: Why hello kernel module didn't output anything?

[Erik Mouw <J.A.K.Mouw@ITS.TUDelft.NL>]

On Thu, Oct 04, 2001 at 02:08:00PM -0400, Hong Hsu wrote:
> Here is my simple question:
> Compile following hello.c with gcc -c hello.c -Wall, then insmod hello.o 
> -o mytest

Add -O2 or your module *will* fail. Also add -D__KERNEL__ -DMODULE.

> The /proc/modules shows  "mytest                   528   0 (unused)"
> But how the module will be called as it suppose to send "Hello, world " 
> to either xterm or konsole? 

Not if you don't tell the kernel what the module init and exit
functions are.

> Thanks,
> -Hong
> 
> 
> #define __KERNEL__         /* We're part of the kernel */
> #define MODULE             /* Not a permanent part, though. */
> 
> /* #include <linux/modversions.h>  */
> #include <linux/module.h>

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

> 
> int init_module()

static int init_module()

> {
>    printk("Hello, world - this is the kernel speaking\n");
>  
>   return 0;
> }
> 
> void cleanup_module()

static void cleanup_module()

> {
>   printk("Short is the life of an LKM\n");
> }

module_init(init_module);
module_exit(cleanup_module);

MODULE_AUTHOR("Hong Hsu");
MODULE_DESCRIPTION("Test module");

EXPORT_NO_SYMBOLS;




Erik

-- 
J.A.K. (Erik) Mouw, Information and Communication Theory Group, Department
of Electrical Engineering, Faculty of Information Technology and Systems,
Delft University of Technology, PO BOX 5031,  2600 GA Delft, The Netherlands
Phone: +31-15-2783635  Fax: +31-15-2781843  Email: J.A.K.Mouw@its.tudelft.nl
WWW: http://www-ict.its.tudelft.nl/~erik/
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