#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include "parapin.h"

int main(int argc, char *argv[])
{
  int i;

  if (pin_init_user(LPT1) < 0)
    exit(0);

  pin_input_mode(LP_DATA_PINS);
  pin_input_mode(LP_SWITCHABLE_PINS);

  printf("\ninit...\n");
  for (i = 1; i <= 17; i++)
    printf("Setting pin %d as %s\n", i, pin_is_set(LP_PIN[i]) ? "HIGH":"LOW");
  printf("\n\n");

  return 0;
}


I try to compile this with
g++ inputtest.c
and I get the following output:
[root@localhost examples]# g++ inputtest.c
/tmp/ccGjp3wX.o: In function `main':
inputtest.c:(.text+0x19): undefined reference to `pin_init_user'
inputtest.c:(.text+0x38): undefined reference to `pin_input_mode'
inputtest.c:(.text+0x44): undefined reference to `pin_input_mode'
inputtest.c:(.text+0x6f): undefined reference to `pin_is_set'
inputtest.c:(.text+0xe1): undefined reference to `pin_is_set'
inputtest.c:(.text+0x14c): undefined reference to `pin_is_set'
collect2: ld returned 1 exit status