MMFShare

#include <WindowsX.h>
HANDLE s_hFileMap=NULL;

// This macro evaluates to the number of elements in an array. 
#define chDIMOF(Array) (sizeof(Array) / sizeof(Array[0]))

inline void chMB(PCSTR s) {
   char szTMP[128];
   GetModuleFileNameA(NULL, szTMP, chDIMOF(szTMP));
   MessageBoxA(GetActiveWindow(), s, szTMP, MB_OK);
}


void CMyMMFShareDlg::OnCreatefile() 
{


         // Create a paging file-backed MMF to contain the edit control text.
         // The MMF is 4 KB at most and is named MMFSharedData.
         s_hFileMap = CreateFileMapping(INVALID_HANDLE_VALUE, NULL, 
            PAGE_READWRITE, 0, 4 * 1024, TEXT("MMFSharedData"));

         if (s_hFileMap != NULL) {

            if (GetLastError() == ERROR_ALREADY_EXISTS) {
               chMB("Mapping already exists - not created.");
               CloseHandle(s_hFileMap);

            } else {

               // File mapping created successfully.

               // Map a view of the file into the address space.
               PVOID pView = MapViewOfFile(s_hFileMap,
                  FILE_MAP_READ | FILE_MAP_WRITE, 0, 0, 0);

               if (pView != NULL) {
                  // Put edit text into the MMF.
                  //Edit_GetText(GetDlgItem( IDC_DATA), 
                  //  (PTSTR) pView, 4 * 1024);
				   GetDlgItemText(IDC_DATA,(PTSTR) pView, 4 * 1024);

                  // Protect the MMF storage by unmapping it.
                  UnmapViewOfFile(pView);

                  // The user can't create another file right now.
                  //Button_Enable(hwndCtl, FALSE);
				  //Button_Enable(GetDlgItem(IDC_CREATEFILE), FALSE);
				  GetDlgItem(IDC_CREATEFILE)->EnableWindow(FALSE);

                  // The user closed the file.
                  //Button_Enable(GetDlgItem(hwnd, IDC_CLOSEFILE), TRUE);
				  GetDlgItem(IDC_CLOSEFILE)->EnableWindow(TRUE);

               } else {
                  chMB("Can't map view of file.");
               }
            }

         } else {
            chMB("Can't create file mapping.");
         }	
}

void CMyMMFShareDlg::OnClosefile() 
{


         if (CloseHandle(s_hFileMap)) {
            // User closed the file, fix up the buttons.
            //Button_Enable(GetDlgItem(hwnd, IDC_CREATEFILE), TRUE);
			GetDlgItem(IDC_CREATEFILE)->EnableWindow(TRUE);
            //Button_Enable(hwndCtl, FALSE);
			GetDlgItem(IDC_CLOSEFILE)->EnableWindow(FALSE);
         }	
}

void CMyMMFShareDlg::OnOpenfile() 
{

         // See if a memory-mapped file named MMFSharedData already exists.
         HANDLE hFileMapT = OpenFileMapping(FILE_MAP_READ | FILE_MAP_WRITE,
            FALSE, TEXT("MMFSharedData"));

         if (hFileMapT != NULL) {
            // The MMF does exist, map it into the process's address space.
            PVOID pView = MapViewOfFile(hFileMapT, 
               FILE_MAP_READ | FILE_MAP_WRITE, 0, 0, 0);

            if (pView != NULL) {

               // Put the contents of the MMF into the edit control.
               //Edit_SetText(GetDlgItem(hwnd, IDC_DATA), (PTSTR) pView);
			   GetDlgItem(IDC_DATA)->SetWindowText((PTSTR) pView);
               UnmapViewOfFile(pView);
            } else {
               chMB("Can't map view.");
            }

            CloseHandle(hFileMapT);

         } else {
            chMB("Can't open mapping.");
         }	
}