Bir module bir başka modülün sadece exported sembollerine erişebilir. Açıklaması şöyle
Modules can only access exported symbols, and exit_task_namespaces isn’t exported — so even though it is visible in the header files, it can’t be used in a module.Exported symbols can be accessed as you’d expect, there’s nothing special to do.
Örnek
Export edilen şey veri yapısı ise şöyle yaparız
struct snd_card *snd_cards[SNDRV_CARDS];
EXPORT_SYMBOL(snd_cards);modul1 şöyle olsun
/* mod1.c */
#include <linux/module.h>
static int mod1_exp_func(int i)
{
pr_info("%s:%d the value passed in is %d\n",
__func__, __LINE__, i);
return i;
}
EXPORT_SYMBOL(mod1_exp_func); /* export static symbol */
static int __init mod1_init(void)
{
pr_info("Initializing simple mod\n");
return 0;
}
static void __exit mod1_exit(void)
{
pr_info("This module is exiting\n");
}
module_init(mod1_init);
module_exit(mod1_exit);
MODULE_LICENSE("GPL v2");/* mod2.c */
#include <linux/module.h>
extern int mod1_exp_func(int);
static int __init mod2_init(void)
{
pr_info("Initializing mod2\n");
pr_info("Calling exported function in mod1\n");
mod1_exp_func(3);
return 0;
}
static void __exit mod2_exit(void)
{
pr_info("mod2 exiting\n");
}
module_init(mod2_init);
module_exit(mod2_exit);
MODULE_LICENSE("GPL v2");