Listing 10. Determining a Device's Global Key and Button
State
uint8_t key_b[KEY_MAX/8 + 1];
memset(key_b, 0, sizeof(key_b));
ioctl(fd, EVIOCGKEY(sizeof(key_b)), key_b);
for (yalv = 0; yalv < KEY_MAX; yalv++) {
if (test_bit(yalv, key_b)) {
/* the bit is set in the key state */
printf(" Key 0x%02x ", yalv);
switch ( yalv)
{
case KEY_RESERVED :
printf(" (Reserved)\n");
break;
case KEY_ESC :
printf(" (Escape)\n");
break;
/* other keys / buttons not shown */
case BTN_STYLUS2 :
printf(" (2nd Stylus Button )\n");
break;
default:
printf(" (Unknown key)\n");
}
}
}
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