test speed of shared memory

// sharedMem.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"

#include <windows.h>
#include <stdio.h>
#include <conio.h>
#include <tchar.h>
#include <vector>

#define BUF_SIZE (8000*2000)

TCHAR szName[]=TEXT("Global\\MyFileMappingObject");


int server(char *exe)
{
   HANDLE hMapFile;
   LPCTSTR pBuf;
   std::vector<char> vBuf(BUF_SIZE);

   hMapFile = CreateFileMapping(
                 INVALID_HANDLE_VALUE,    // use paging file
                 NULL,                    // default security 
                 PAGE_READWRITE,          // read/write access
                 0,                       // maximum object size (high-order DWORD) 
                 BUF_SIZE,                // maximum object size (low-order DWORD)  
                 szName);                 // name of mapping object
 
   if (hMapFile == NULL) 
   { 
      _tprintf(TEXT("Could not create file mapping object (%d).\n"), 
             GetLastError());
      return 1;
   }
   pBuf = (LPTSTR) MapViewOfFile(hMapFile,   // handle to map object
                        FILE_MAP_ALL_ACCESS, // read/write permission
                        0,                   
                        0,                   
                        BUF_SIZE);           
 
   if (pBuf == NULL) 
   { 
      _tprintf(TEXT("Could not map view of file (%d).\n"), 
             GetLastError()); 

       CloseHandle(hMapFile);

      return 1;
   }

   DWORD dwTm = GetTickCount();

   CopyMemory((PVOID)pBuf, &vBuf[0], vBuf.size());
   
   DWORD dwDiff = GetTickCount()-dwTm;

   printf("Copy from user to shared memory use time %d\n", dwDiff);

   char cmd[1000];
   sprintf(cmd,"%s c", exe);
   system(cmd);
   getch();

   UnmapViewOfFile(pBuf);
   CloseHandle(hMapFile);

   return 0;
}

int client()
{
   HANDLE hMapFile;
   LPCTSTR pBuf;
    std::vector<char> vBuf(BUF_SIZE);

   hMapFile = OpenFileMapping(
                   FILE_MAP_ALL_ACCESS,   // read/write access
                   FALSE,                 // do not inherit the name
                   szName);               // name of mapping object 
 
   if (hMapFile == NULL) 
   { 
      _tprintf(TEXT("Could not open file mapping object (%d).\n"), 
             GetLastError());
      return 1;
   } 
 
   pBuf = (LPTSTR) MapViewOfFile(hMapFile, // handle to map object
               FILE_MAP_ALL_ACCESS,  // read/write permission
               0,                    
               0,                    
               BUF_SIZE);                   
 
   if (pBuf == NULL) 
   { 
      _tprintf(TEXT("Could not map view of file (%d).\n"), 
             GetLastError()); 

      CloseHandle(hMapFile);

      return 1;
   }

   DWORD dwTm = GetTickCount();

   CopyMemory(&vBuf[0], (PVOID)pBuf, vBuf.size());

   DWORD dwDiff = GetTickCount()-dwTm;

   printf("Copy from shared memory to user use time %d\n", dwDiff);
   
   UnmapViewOfFile(pBuf);
    
   CloseHandle(hMapFile);
 
   return 0;
}


int _tmain(int argc, char *argv[])
{
    if(argc>1)
    {
        if(argv[1][0]=='c')
            client();
    }
    else
        server(argv[0]);

    return 0;
}