[Z88dk-users] Reading multiple keys

[thricenightly (<del...@gm...>]

I'm trying to work out why this program won't show all 5 keys being pressed simultaneously:

[code]#include <stdio.h>
#include <input.h>
#include <arch/zx.h>

int main()
{
  zx_cls(PAPER_WHITE);
  while( 1 ) {

    printf("\x16\x01\x01");

    printf("Scancode is 0x%04X\n",   in_key_pressed( IN_KEY_SCANCODE_q ));
    printf("Scancode is 0x%04X\n",   in_key_pressed( IN_KEY_SCANCODE_a ));
    printf("Scancode is 0x%04X\n",   in_key_pressed( IN_KEY_SCANCODE_o ));
    printf("Scancode is 0x%04X\n",   in_key_pressed( IN_KEY_SCANCODE_p ));
    printf("Scancode is 0x%04X\n\n", in_key_pressed( IN_KEY_SCANCODE_SPACE ));
  }
}[/code]
I think it's the nature of the keyboard matrix as described here:

http://www.worldofspectrum.org/faq/reference/48kreference.htm

but I can't quite get my head around what's happening. Can someone explain?