/*
Output    Input
Data0     BUSY
DATA1     PAPERE
DATA2     SELECT
DATA3     ERROR
DATA4     ACK

Results of ioctl(fd, PPIGSTATUS, &status):

Bit   0V   5V  name
MSB   1    0   BUSY
6th   0    1   ACK
5th   0    1   PAPERE  
4th   0    1   SELECT
3rd   0    1   ERROR
2nd            NC
1st            NC
0th            NC
*/

#include <fcntl.h>                    /* for open(2) close(2) */
#include <sys/ioctl.h>                /* for open(2) close(2) */
#include </sys/dev/ppbus/ppi.h>       /* for ppi(4) */
#include </sys/dev/ppbus/ppbconf.h>   /* for ppi(4) */
#include <stdio.h>                    /* for getchar(3), fprintf(3) */

void printbinary(u_int8_t val)
{
  u_int8_t cmp;
  cmp = 0x80;
  fprintf(stdout, "%1d\n", (cmp & val)?1:0);

}


main()
{
  int fd;           /* Integer which points /dev/ppi */
  u_int8_t val;     /* Data to output */
  u_int8_t status;     /* Status register */

  if ((fd=open("/dev/ppi0", O_RDWR)) == -1)
    {
      fprintf(stderr, "Error!\n"); exit();
    }

  ioctl(fd, PPIGSTATUS, &status);
  printbinary(status);

  close(fd);
}