what header file needed in kwrite? i have problem when compling my simple program...pls advise if the below program have any error...i have 13 error on that program...thanks for your help...

#include <linux/module.h> /* Needed by all modules */
#include <linux/kernel.h> /* Needed for KERN_ALERT */

int init_module(void)
{
printk("<1>Hello world 1.\n");
return 0;
}


void cleanup_module(void)
{
printk(KERN_ALERT "Goodbye world 1.\n");
}