The RTOS that cuts development time in half

#include <nuttx/config.h>
#include <stdio.h>
#include <pthread.h>
#include <semaphore.h>

/* POSIX-compatible semaphore for thread synchronization */
sem_t g_sem;

/* Thread function - standard POSIX API */
void *thread_func(void *arg)
{
  while(1) {
    /* Wait on semaphore */
    sem_wait(&g_sem);
    
    /* Critical section */
    printf("Thread executing critical section\n");
    
    /* Sleep is also POSIX-compatible */
    sleep(1);
  }
  return NULL;
}

int main(int argc, char *argv[])
{
  pthread_t thread;
  
  /* Initialize semaphore */
  sem_init(&g_sem, 0, 0);
  
  /* Create thread using standard POSIX API */
  pthread_create(&thread, NULL, thread_func, NULL);
  
  while(1) {
    /* Post to semaphore to wake thread */
    sem_post(&g_sem);
    sleep(2);
  }
  
  return 0;
}