NAME

kbdputc, kbdrepeat, kbdclock, kbdq − keyboard interface to cons(3)

SYNOPSIS

#include "keyboard.h"

voidkbdputc(Queue *q, int c);

voidkbdrepeat(int on);

voidkbdclock(void);

externQueue *kbdq;

DESCRIPTION

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:

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

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. 

SOURCE

/os/*/kbd*.c

SEE ALSO

cons(3), utf(6), qio(10.2)