#ifndef SEMAPHORE_H_
#define SEMAPHORE_H_

#include <pthread.h>		// has pthread_ routines
#include <semaphore.h>		// has sem_ routines

// ---- Class for semaphore ------------------------------------------

// By defining a class for semaphores, we ensure that sem_init 
//   and sem_destroy are called automagically (respectively,
//   when a semaphoreObj is declared and goes out of scope).

class semaphoreObj {

public:
  // Constructor (one parameter) and destructor.
  semaphoreObj(const unsigned int initVal) {
    sem_init(&theSemaphore, 0, initVal); 
  }
  ~semaphoreObj(void) { sem_destroy(&theSemaphore); }

private:
  // Copy constructor and assignment operator:  Make private so
  //   they can't be used (and we don't have to write them).
  semaphoreObj(const semaphoreObj & d);
  semaphoreObj & operator= (const semaphoreObj & d);

public:

  // Function to execute "wait" on semaphore.
  void wait(void) { sem_wait(&theSemaphore); }

  // Function to execute "signal" on semaphore.
  // (Called post to be consistent with sem_ routine naming.
  void post(void) { sem_post(&theSemaphore); }

private:		// member variables
  sem_t theSemaphore;
};

#endif // SEMAPHORE_H_