Keys

Overview

The Libreciva key function provides access to the reciva keyboard.

In order to use the library function, you must include the header file:

#include "key.h"

struct key_handler *key_init()

This function must be called to initialise the keyboard interface. It returns a handle structure, which must be used whenever the keyboard is polled with key_poll().

int key_poll(struct key_handler *eh, struct key *ev)

This function polls the keyboard, and returns:

• -1 - There has been a problem with the key interface
• 0 - No key events are queued
• 1 - Key event has occurred

When the function returns '1', the key structure is updated to contain details of the selected key.

struct key {
  enum key_state state ;
  enum key_id id ;
}

The state is one of the following:

• KEY_STATE_PRESSED
• KEY_STATE_RELEASED

The id is one of the following:

• KEY_ID_1
• KEY_ID_2
• KEY_ID_3
• KEY_ID_4
• KEY_ID_5
• KEY_ID_SHIFT
• KEY_ID_BACK
• KEY_ID_SELECT
• KEY_ID_REPLY
• KEY_ID_POWER
• KEY_ID_LEFT
• KEY_ID_RIGHT
• KEY_ID_VOLUP
• KEY_ID_VOLDN
• KEY_ID_BROWSE

Example

#include "key.h"
#include <stdio.h>

main()
{
  struct key k ;
  struct key_handler *h ;

  /* initialise / open the keyboard */
  h=key_init() ;
  if (h==NULL) exit(1) ;

  /* wait for a key change */
  while (!key_poll(h, &k)) ;

  /* finally, report what happened */
  printf("Key State = %d, Key ID = %d
", k.state, k.id) ;
}