apps/tests/tests/Mutex/fivemutex.c

   1 /* fivemutex.c: hungry philosophers problem
   2  *
   3  * (c) Copyright D.W.Howells 2000.
   4  *     All rights reserved
   5  */
   6 #include <windows.h>
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9
  10 #define ERR(X,Y) do { if (X) { perror(""Y""); return 1; } } while(0)
  11 #define RUNLENGTH 4
  12
  13 int count[5];
  14
  15 const char *names[] = {
  16         "five/1", "five/2", "five/3", "five/4", "five/5"
  17 };
  18
  19 DWORD WINAPI child(LPVOID tparam)
  20 {
  21         HANDLE left, right, first, second;
  22         const char *lname, *rname;
  23         int pid = (int) tparam;
  24         int wt;
  25
  26         lname = names[pid%5];
  27         rname = names[(pid+1)%5];
  28
  29         /* create a mutex */
  30         left = CreateMutex(NULL,0,lname);       ERR(!left,"create left");
  31         right = CreateMutex(NULL,0,rname);      ERR(!left,"create right");
  32
  33         printf("[%d] left: %p [%s]\n",pid,left,lname);
  34         printf("[%d] right: %p [%s]\n",pid,right,rname);
  35
  36         /* pick the forks up in numerical order, else risk starvation */
  37         if (pid%5 < (pid+1)%5) {
  38                 first = left;
  39                 second = right;
  40         }
  41         else {
  42                 first = right;
  43                 second = left;
  44         }
  45
  46         for (;;) {
  47                 /* grab the left mutex */
  48                 wt = WaitForMultipleObjects(1,&first,0,INFINITE);
  49                 if (wt!=WAIT_OBJECT_0)
  50                         goto wait_failed;
  51
  52                 /* grab the right mutex */
  53                 wt = WaitForMultipleObjects(1,&second,0,INFINITE);
  54                 if (wt!=WAIT_OBJECT_0)
  55                         goto wait_failed;
  56
  57                 /* got it */
  58                 count[pid]++;
  59
  60                 /* pass the mutexes */
  61                 ERR(!ReleaseMutex(left),"release left");
  62                 ERR(!ReleaseMutex(right),"release right");
  63                 continue;
  64
  65             wait_failed:
  66                 switch (wt) {
  67                 case WAIT_OBJECT_0+1:
  68                         printf("[%d] obtained mutex __1__\n",pid);
  69                         exit(1);
  70                 case WAIT_ABANDONED_0:
  71                 case WAIT_ABANDONED_0+1:
  72                         printf("[%d] abandoned wait\n",pid);
  73                         continue;
  74                 case WAIT_TIMEOUT:
  75                         printf("[%d] wait timed out\n",pid);
  76                         exit(1);
  77                 default:
  78                         ERR(1,"WaitForMultipleObjects");
  79                 }
  80
  81                 return 1;
  82         }
  83
  84         /* close the handles */
  85         ERR(!CloseHandle(left),"close left");
  86         ERR(!CloseHandle(right),"close right");
  87
  88         return 0;
  89
  90 }
  91
  92 int main()
  93 {
  94         HANDLE hThread[5];
  95         DWORD tid;
  96         int loop;
  97
  98         for (loop=0; loop<5; loop++) {
  99
 100                 hThread[loop] = CreateThread(NULL,                                      /* thread attributes */
 101                                                                          0,                                     /* stack size */
 102                                                                          child,                         /* start address */
 103                                                                          (void*)loop,                   /* parameter */
 104                                                                          0,                                     /* creation flags */
 105                                                                          &tid                                   /* thread ID */
 106                                                                          );
 107                 if (!hThread[loop])
 108                 {
 109                                 ERR(1,"CreateThread");
 110                 }
 111         }
 112
 113         WaitForMultipleObjects(5,hThread,0,RUNLENGTH*1000);
 114
 115         for (loop=0; loop<5; loop++)
 116                 TerminateThread(hThread[loop],0);
 117
 118         for (loop=0; loop<5; loop++)
 119                 printf("[%d] ate %d times (%d times per second)\n",
 120                        loop,count[loop],count[loop]/RUNLENGTH
 121                            );
 122
 123         return 0;
 124 }