#include <linux/utsname.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

int main()
{
  int retval;
  char hostname[__NEW_UTS_LEN];

  // Print out current hostname
  if ((retval = gethostname(hostname, __NEW_UTS_LEN)) == -1) {
    printf("call to gethostname() failed, retval=%d: %s\n", retval, strerror(errno));
    return 1;
  };
  
  printf("gethostname()=\"%s\"\n", hostname);

  // Set "new" hostname
  if ((retval = sethostname((char *)-1, 10)) != -1) {
    // We really EXPECT this to fail!
    printf("The Penguin is in trouble!\n");
    return 2;
  } else
    printf("sethostname(INVALID, 10)=%d (error \"%s\")\n", retval, strerror(errno));

  // And now once again:
  if ((retval = gethostname(hostname, __NEW_UTS_LEN)) == -1) {
    printf("call to gethostname() failed, retval=%d: %s\n", retval, strerror(errno));
    return 1;
  };
  
  printf("gethostname()=\"%s\"\n", hostname);

  return 0;
};