// sparksandflames.com

#include <stdio.h>
#include <stdlib.h>

#include <windows.h>
#include <string.h>
#include <conio.h>
#include <process.h>


HANDLE  mutexObject;

int     tcnt = 4;                   // Number of threads to start
int     threadsStarted;             // Number of threads started 

double f[100];




void WinThreadFunction( void *argPointer )
{
   int w;
   int i,j;
   int tot;
   int x = 100000;                 
  
   // GET THREAD INDEX
   
   w =  (int ) argPointer;
   f[w] = 0 ;


   // INCREASE THREAD COUNT
      
   WaitForSingleObject( mutexObject, INFINITE );
   threadsStarted++;
   printf("Start Thread = %d Count = %d\n",w,threadsStarted);
   ReleaseMutex(mutexObject);
  

   // DO SOME BUSY WORK THE COMPILER WON'T OPTIMIZE AWAY

   tot = 0;
   for(i=0;i<x;i++)
   {
     for(j=0;j<x;j++)
     {
         f[w] = f[w] + 1.00;
         tot++;
     }
   }

   // DONE
    
  //  printf("Loop Finished Thread %d Loop %d F %.0f\n",w,i,f[w]);
 
   printf("Finished Thread %2d\n",w);

   // ACCURACY TEST

   if (tot != x*x)
      printf("i<>x*x %d %d\n",i,x*x);
  
  fflush(stdout);

  // DECREASE COUNT
       
  WaitForSingleObject( mutexObject, INFINITE );  
  threadsStarted--;
  ReleaseMutex(mutexObject);

  // SEE HOW EVEN THE WORKLOAD IS
  
  printf("Stop Thread = %d  Remaining = %d\n",w,threadsStarted);
  for(i=0;i<tcnt;i++)
     printf("%12.0f",f[i]);
  printf("\n");
  
  
}




int main(int argc, char *argv[])                          
{
   int ix;
   int threadid;

   long unsigned start,end,wallstart,wallend;
   
   HANDLE a[100];



    // PARAMETER 1 OVER RIDES DEFAULT

    if (argc == 2)
    {
        tcnt = atoi(argv[1]);
        if (tcnt < 1 || tcnt > 100 )
        {
           printf("winthread('%d'): Thread count must be between 1 - 100\n",tcnt);
           return 0;
        }
    }

   printf("%d threads\n",tcnt);


   /* Start Timers */
      
   wallstart = time(NULL);   
   start     = clock(); 

   /* Reset thread count. */
  
   threadsStarted = 0;
  
   /* Create the mutex */
  
   threadsStarted = 0;
  
   mutexObject = CreateMutex( NULL, FALSE, NULL );   /* Cleared */
  
   if(mutexObject == NULL && GetLastError() != ERROR_SUCCESS) 
   {
      printf("failed to obtain a proper mutex for multithreaded application");
      exit(1);
   }
    

   // START TCNT THREADS
  
   for(ix=0;ix < tcnt; ix++)
     a[ix] = (HANDLE) _beginthread(  WinThreadFunction, 0,  (void *) ix );


   // WAIT FOR TCNT THREADS TO FINISH
  
   WaitForMultipleObjects(tcnt, a, TRUE, INFINITE);

   CloseHandle( mutexObject );


   // RUNTIMES

   end       = clock();   
   wallend   = time(NULL);
   
   printf("Elapsed time: %lu clocks %lu seconds", end - start, wallend - wallstart);
   
   return 0;
}