Hi, I'm trying to use MapViewOfFile in a 64 bit process on a file that is already mapped to memory of another 32 bit process. It fails and gives me an "access denied" error. Is this a known Windows limitation or am I doing something wrong? Same code works fine with 2 32bit processes.

The code sort of looks like this:

hMapFile = OpenFileMapping(FILE_MAP_ALL_ACCESS, FALSE, szShmName);
if (NULL == hMapFile)
{   /* failed to open - create new (this happens in the 32 bit app) */
   SECURITY_ATTRIBUTES  sa;
   sa.nLength = sizeof(SECURITY_ATTRIBUTES);
   sa.bInheritHandle = FALSE;  
   /* give access to members of administrators group */
   BOOL success = ConvertStringSecurityDescriptorToSecurityDescriptor(
            "D:(A;OICI;GA;;;BA)",
            SDDL_REVISION_1,
            &(sa.lpSecurityDescriptor),
            NULL);
   HANDLE hShmFile = CreateFile(FILE_FAXCOM_SHM, 
            FILE_ALL_ACCESS, 0, 
            &sa, 
            OPEN_ALWAYS, 0, NULL);

   hMapFile = CreateFileMapping(hShmFile, &sa, PAGE_READWRITE, 
            0, 
            SHM_SIZE, 
            szShmName);

   CloseHandle(hShmFile);
}

// this one fails in 64 bit app
pShm = MapViewOfFile(hMapFile, FILE_MAP_ALL_ACCESS, 0, 0, SHM_SIZE);