5個哲學家搶叉子程式. 示範死結

#include <stdio.h>
#include <stdlib.h>
#include <windows.h>
                                          
enum { N = 5 };                           /* number of philosphers */

static HANDLE fork[N];          /* model forks as mutex semaphores */

void think(long n) {
   printf("Philosopher %d is thinking\n", n);
   Sleep(10);
   printf("Philosopher %d is hungry\n", n);
} 

void eat(long n) {
   printf("Philosopher %d is eating\n", n);
   Sleep(0);
} 

long WINAPI philosopher(long n) {   /* model philosophers as tasks */
   for (;;) { 
      think(n);               // first the philosopher thinks for a while
                      // after thinking the philosopher becomes hungry...
      WaitForSingleObject(fork[(n + 1) % N], INFINITE);  // get left fork
      Sleep(0);             /* yield讓出 the CPU (simulate preemption ) 去掉這句就不會死結了嗎?*/
      WaitForSingleObject(fork[n], INFINITE);           // get right fork
      eat(n);                      // got both forks, can eat for a while
      ReleaseMutex(fork[(n + 1) % N]);               // release left fork
      ReleaseMutex(fork[n]);                        // release right fork
   }
   return 0;
} 

main() {
   int n;
   for (n = 0; n < N; ++n) {                       /* create forks */
  fork[n] = CreateMutex(NULL,
// default security attributes
  FALSE,
// initially not owned/* not owned */
  NULL);
// unnamed mutex

  if (fork[n] == NULL) 
  {
  printf("CreateMutex error: %d\n", GetLastError());
  return;
  }
 
   }
   for (n = 0; n < N; ++n) {                /* create philosophers */
      int threadID;
 CloseHandle(CreateThread(
 NULL,        // default security attributes
 0,           // default stack size
 (LPTHREAD_START_ROUTINE)philosopher,
 (LPVOID)n,    //  thread function arguments
 0,            // default creation flags
 &threadID));  //thread identifier
   }
   scanf("%c", &n);            /* wait for the user to press Enter */    
   return 0;
}