#include <pthread.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>

int main(void) {
  int err;
  struct timespec tout;
  struct tm *tmp;
  char buf[64];

  pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
  pthread_mutex_lock(&lock);
  printf("mutex is locked\n");
  clock_gettime(CLOCK_REALTIME, &tout);
  tmp = localtime(&tout.tv_sec);
  strftime(buf, sizeof(buf), "%r", tmp);
  printf("current time is %s\n", buf);
  
  tout.tv_sec += 10;

  err = pthread_mutex_timedlock(&lock, &tout);
  clock_gettime(CLOCK_REALTIME, &tout);
  tmp = localtime(&tout.tv_sec);
  strftime(buf, sizeof(buf), "%r", tmp);

  printf("the time is now %s\n", buf);
  if(err == 0)
    printf("mutex locked again!n");
  else
    printf("can't lock mutex again: %s\n", strerror(err));

   return 0;
}