#include <pthread.h>
#include <semaphore.h>
#include <stdio.h>
#include <stdlib.h>

#define NUM_THREADS 5
sem_t semaphore;

void *worker_thread(void *arg) {
  int thread_num = *((int*) arg);
  printf("Thread %d waiting on semaphore...\n", thread_num);
  sem_wait(&semaphore);
  printf("Thread %d enters critical section...\n", thread_num);
  // Acción crítica
  printf("Thread %d exits critical section...\n", thread_num);
  sem_post(&semaphore);
  return NULL;
}

int main() {
  pthread_t threads[NUM_THREADS];
  int thread_args[NUM_THREADS];
  sem_init(&semaphore, 0, 1);
  for (int i = 0; i < NUM_THREADS; ++i) {
    thread_args[i] = i;
    pthread_create(&threads[i], NULL, worker_thread, &thread_args[i]);
  }
  for (int i = 0; i < NUM_THREADS; ++i) {
    pthread_join(threads[i], NULL);
  }
  sem_destroy(&semaphore);
  return 0;
}