#ifndef LOCK_H_
#define LOCK_H_

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

// ---- Class for lock -----------------------------------------------

// By defining a class for locks, we ensure that pthread_mutex_init 
//   and pthread_mutex_destroy are called automagically (respectively,
//   when a lockObj is declared and goes out of scope).

class lockObj {

public:
  // Constructor (no arguments) and destructor.
  lockObj(void) { pthread_mutex_init(&theLock, NULL); }
  ~lockObj(void) { pthread_mutex_destroy(&theLock); }

  // Function to acquire the lock.
  void lock(void) { pthread_mutex_lock(&theLock); }

  // Function to release the lock.
  void unlock(void) { pthread_mutex_unlock(&theLock); }

private:
  // Make copy constructor and assignment operator private
  //   so they can't be used (since it's not clear this would 
  //   make sense).
  lockObj(const lockObj & d);
  lockObj & operator= (const lockObj & d);

  // member variables
  pthread_mutex_t theLock;
};

#endif // LOCK_H_