Calling Win32 DLL from 64-bit WPF through ATL 32-bit Surrogate COM

(1) How to tell if a DLL is 32-bit or 64-bit

 dumpbin /headers MyServer.dll to tell by file Header x86 or x64

(2) Run 32-Bit COM in surrogate Procese so can be called from 64-bit WPF.(one kind of IPC)
       http://www.gfi.com/blog/32bit-object-64bit-environment/ 


 
   Locate your COM object GUID under the HKey_Classes_Root\Wow6432Node\CLSID\[GUID] 
  
    Once located add a new REG_SZ (string) Value. Name should be AppID and data should be the same COM object GUID you have just searched for  
  
    Add a new key under HKey_Classes_Root\Wow6432Node\AppID\
    The new key should be called the same as the com object GUID  
  
    Under the new key you just added, add a new REG_SZ (string) Value, and call it DllSurrogate. Leave the value empty  
 
    Create a new Key under HKey_Local_Machine\Software\Classes\AppID\
    Again the new key should be called the same as the COM object’s GUID. No values are necessary to be added under this key. 

(3) Step-by-step ALT 32-bit COM Creation (check to make sure project properties are x86)
      http://msdn.microsoft.com/en-us/library/dssw0ch4%28d=printer,v=vs.90%29.aspx
      http://msdn.microsoft.com/en-us/library/9yb4317s.aspx
    Note that C# COM is not usable in (2), especially HKey_Classes_Root\Wow6432Node\CLSID\[GUID] is not there. 
    Also each build of ATL COM project will override this location and need to add back AppID={Guid}
(4) A good overall review of 64-bit calling 32-bit using IPC
    http://blog.mattmags.com/2007/06/30/accessing-32-bit-dlls-from-64-bit-code/

(5) Dynamic Loading Win32 DLL to access its functions:

#pragma hdrstop
#pragma package(smart_init)

// CObject1

HINSTANCE hMWXUSB=0;
typedef int (__cdecl *MYPROC)(LPWSTR); 

typedef unsigned char (ACCEPT_LED)(int data);
ACCEPT_LED *lpacceptled;

typedef unsigned char (OPEN_USB)(void);
OPEN_USB *lpopenusb;


STDMETHODIMP CObject1::get_GetANum(SHORT* pVal)
{
 hMWXUSB=LoadLibrary(L"MWXUSB.DLL");
 MYPROC Accept_LED; 

 //Accept_LED = (MYPROC) GetProcAddress(hMWXUSB, "Accept_LED"); 

    if( (hMWXUSB = LoadLibrary(L"MWXUSB.DLL")) == NULL )
   {
        *pVal=-5;
        return S_OK;
   }

       if( (lpopenusb=(OPEN_USB*)GetProcAddress(hMWXUSB,"Open_USB" ))==NULL )
   {
        *pVal=-6;
        return S_OK;
   }
       unsigned char ucOpen;
   ucOpen =  (*lpopenusb)();

    if( (lpacceptled=(ACCEPT_LED*)GetProcAddress(hMWXUSB,"Accept_LED" ))==NULL )
   {
       *pVal=-1105;
        return S_OK;
   }
    unsigned char ch;
 ch = (*lpacceptled)(1);
  if(ch)
   {
    *pVal=-2105;
    return S_OK;
  }


 *pVal=105;

 return S_OK;
}