I have little programm for working with io :
#include <machine/types.h>
#include <machine/pio.h>
...

 if (dummy=fopen("/dev/io", "r")) {
                 outb(port_addr, byte);
    fclose(dummy);
  }

...

But when it runs(37a 1 - for working with lpt port)  i have "bus error
(core dumped)" 
When i run gdb on core file i see that it fails on outb function.
Any ideas? On freebsd it works good.