register_console - take on kernel console duties
extern void register_console(void(*proc))(const char*))
This function registers with the kernel a function to
display all the kernel messages printed by the printk(9)
This function is normally called once at boot time by the
device driver for the console device, whatever that turns
out to be for the machine. The console procedure is only
called to print messages that are to be printed, the filter-
ing for log level is done already.
Stephen Williams <firstname.lastname@example.org>
Only one console can exist at a time, and there is no way to
know if any other device has registered as a console.