Message Print_Kernel Interface

Message Print_Kernel Interface
<linux/kernel.h>
printk(const char* fmt, ...);
printk(LOG_LEVEL message);
// ex)
printk("<1>Hello, World!");
printk(KERN_WARNING "warning...\n"); //<4>
KERN_WARNING
KERN_EMERG, KERN_ALERT, KERN_ERR, KERN_WARNING, KER_INFO, KERN_DEBUG