kbdputc, kbdrepeat, kbdclock, kbdq - keyboard interface to cons(3) #include "keyboard.h"

void kbdputc(Queue *q, int c)

void kbdrepeat(int on)

void kbdclock(void)

extern Queue *kbdq;

This is the internal interface between /dev/keyboard of cons (3) and the architecture-dependent keyboard driver. Before calling any of these functions, the global variable kbdq must be initialised; cons (3) does not initialise it. This is usually done during system initialisation by the keyboard driver's kbdinit function , as follows: .EX kbdq = qopen(4*1024, 0, 0, 0); qnoblock(kbdq, 1);

Kbdputc puts a 16-bit Unicode character c (ie, a `rune') on the given q , as a sequence of bytes in UTF-8 encoding (see utf (6)). If c is the special value Latin (defined by keyboard.h ), kbdputc starts collecting characters, looking for the typeable representations of Unicode characters defined by keyboard (6); at the end of a complete such sequence, kbdputc queues the UTF-8 encoding of the corresponding Unicode character. It is up to the keyboard driver to map a suitable physical keyboard character (or combination of characters) to the code Latin .

Drivers that need to implement repeat of keypresses in software should call

.EX addclock0link(kbdclock);

at the end of kbdinit , to cause kbdclock to be called each clock tick. Kbdrepeat can then be called to enable ( on is non-zero) or disable it ( on is zero). When repeat is on, kbdclock (when called) will periodically call "kbdputc(" kbdq , c ) where c is the last rune given to kbdputc . The driver is responsible for enabling and disabling repeat appropriately; for instance, function keys and certainly Latin should typically not be repeated.

/os/*/kbd*.c cons (3), utf (6), qio (10.2)