#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <time.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <setjmp.h>
#include <string.h>

jmp_buf env;

void pipehandler(int sig)
{
  longjmp(env,1);
}

int main()
{
  time_t unixaika;
  struct tm *aika;
  int f;
  char s[] = "00:00:00\n";

  if (mkfifo("kello", 0644)) {
    perror("mkfifo");
    exit(1);
  }

  setjmp(env);

  signal(SIGPIPE, pipehandler);

  while (1) {
    close(f); /* ignore errors */
    if ((f=open("kello",O_WRONLY))<0) {
      perror("open");
      exit(1);
    }
    unixaika=time(NULL);
    aika = localtime(&unixaika);
    sprintf(s,"%02d:%02d:%02d\n", aika->tm_hour, aika->tm_min, aika->tm_sec);
    write(f,s,strlen(s));
  }
}