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NAME

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

SYNOPSIS

#include keyboard.h

void kbdputc(Queue *q, int c)

void kbdrepeat(int on)

void kbdclock(void)

extern Queue *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)