C / C++ / MFC

#include <Windows.h>

int main(int argc, char* argv[])
{
   HANDLE hFile = NULL;
   DWORD dwFileSize = 0;
   DWORD dwError = 0;

   __try
   {
      hFile = ::CreateFile( 
           argv[1],
           GENERIC_WRITE,
           FILE_SHARE_WRITE,
           NULL,
           OPEN_EXISTING,
           FILE_FLAG_RANDOM_ACCESS,
           NULL);

      if( hFile == INVALID_HANDLE_VALUE )
      {
         return 1;
      }

      // What total size is it?
      dwFileSize = ::GetFileSize( hFile, NULL );

      // Take away one byte
      if( ::SetFilePointer( hFile, dwFileSize - 1, NULL, FILE_BEGIN ) != -1 )
      {
          // Only if we successfully moved to the next-to-last byte 
          // do we want to move the EOF marker
          if( !::SetEndOfFile( hFile ) )
          {
              dwError = ::GetLastError();
              return dwError;
          }
      }
      else
      {
          dwError = ::GetLastError();
          return dwError;
      }
    }
    _finally
    {
       // This is important.  Once you close the file, it will be written 
       // to disk		
       CloseHandle( hFile );
    }
    return 0;
}

</code>