diner.c

用c++包装好的线程库,直接拿来使用,提高效率.

//
// This is a philosopher demo, using process scoping.
#include <thread.h>

#include <iostream>

#define MAX_PHILOSOPHERS          5

using namespace std;
using namespace cpp_threads;

int main()
{
  Mutex*     p_fork;
  Semaphore* sem;
  bool fork_v = false;
  int lfork, rfork, _nr, _forks = MAX_PHILOSOPHERS, _count;
  
  Pthread::setProject( "/tmp/philosophy" );
  sem    = new Semaphore(attributes::process_shared_e);
  p_fork = new Mutex[MAX_PHILOSOPHERS](attributes::process_shared_e);
  if ( (_nr = sem->post()) > MAX_PHILOSOPHERS ) {
    sem->tryWait();
    exit(0);
  }
  _count = _forks;
  _nr -= 1;
  lfork = _nr-1 >= 0 ? _nr-1 : _forks-1;
  rfork = lfork+1 >= _forks ? 0 : lfork+1;
  while(_count-- > 0) {
    cout << "Philosopher " << _nr << " looking for " << lfork << ',' <<  rfork << endl;
    while( fork_v == false ) {
      if (p_fork[lfork].tryLock() == 0) {
	if (p_fork[rfork].tryLock() == 0)
	  fork_v = true;
	else
	  p_fork[lfork].unLock();
      }
    }
    cout << "Philosopher " << _nr << " using (" << lfork << ',' << rfork << ")\n";
    sleep(2);
    fork_v = false;
    cout << "Philosopher " << _nr << ": sleeping\n";
    p_fork[lfork].unLock();
    p_fork[rfork].unLock();
    sleep(2);
  }
  cout << _nr << " has finished dining." << endl;
  sem->tryWait();
  return 0;
}