This document will help with the making of a Binary input-output DLL ATL/COM interface with MFC.

Studio version used: 1.20.0

Requirements: Studio 1.10.x or above. Backward and forward compatibility between the COM build with one version of the Studio library and other Studio versions is not guarantied.

Introduction: First we will address the issue of what to do with the dll that we wish to link to the Atlas with a Binary IO and MFC. Other documents will address the issue of using the support of Text IO and Binary IO resources with an exe without the usage of GUI within the COM environment.

Then we will see the Atlas and what it takes with a 416 environment to make use of it.

Dll versus Exe:

1. Advantage of Dlls versus Exe:

· The Dll uses less resources than the Exe.

· The Dll can easily remain on top of the Wrts.

· The accelerators are directly passed on to the Wrts without additional code. When the Exe has the focus, it will need some code in order to pass on the accelerator destined for the Wrts.

· The message loop for painting the GUI is taken care of by the Wrts. For the Exe, the code needs to be placed into the Exe which may be done by the wizard to some extent.

· The Dll will be slightly faster than the Exe. This will however only make a difference for repeated transfer of a large amount of data.

2. Advantage of the Exe versus Dll:

· The Exe is more isolated than the Dll and if it crashes, it will not affect the Wrts. This may be an issue if the Exe links to code that is not stable.

· The Exe can be moved in front or behind the Wrts at will.

· The Exe can be run remotely.

1 When generating a dll with MSVC 6++

Combining ATL and MFC is not totally straightforward with the wizards. It is easier to deal with fixing the ATL problems on top of a MFC project than the other way around so we are going to do just that:

First start an MFC project and then try to add the ATL to it.

1.1 Starting a simple ATL resource with MFC support, dialog based with one toggle button:

· From File/New…, select an ATL COM Application and select a project name ComDll2 as seen below:

· Click on OK

· Select Dynamic Link Library (DLL) and Support MFC.

· Click on Finish.

· Click OK on the following window:

· If we look at the image below, we can see what the project should look like.

· Go into the Workspace and select the ResourceView Tab.

· Right click on ComDll2 resources and select insert:

· Click on Dialog and select New.

· You will now have a the following window:

· Left click on the the OK and press delete. Left click on the Cancel button and press delete.

· In the Controls window, select the check box (square item with an x in it). Left click on it and drag it onto the Dialog box. You may resize the Dialog box at will. You should have the following:

· Right click on the checkbox and select the Properties. You will see the windows below and change the caption to Button.

· In the Style tab, select Push-like check box.

· In the Extended Styles, select the options that you see fit.

· Then right click on the dialog box and select Properties. In Style, uncheck the title bar and close that window:

· You will see now have the following project:

· Go into Project/Settings… and you’ll see the following window

· Select All configurations for Settings For: and Use MFC in a Static Library for Microsoft Foundation Classes: as seen below.

· Click on OK.

· Build your project by going into Build/Build ComDll2.dll or press F7. Your project should build without errors.

· Now, you can write click on the dialog box window and select Class Wizard. You will see the following window and click OK by accepting the default:

· You will now be asked to chose a name for the new Dialog class and type in CComDllDlg:

· Press on OK

· You will now see the following Window:

· This is where you may add any functionality related to clicking on the window. We will in our case only be interested in what happens when we click on the button. No implementation of that functionality is necessary in our case.

In the event that you wished to implement it, you will have to select IDC_CHECK1 on the Object Ids window.

Then you will click on BN_CLICKED in the Messages: Window.

· Click on the Add Function button. A Add Member Function will open.

· Click on OK after allowing the default name to be chosen. Now you have allowed the wizard to add the code to your project.

· Click on OK.

1.2 Now, we will add the ATL environment:

· Go to Insert and select New ATL Object.

· Now you should see the following window:

· Select Simple Object as seen below and click on Next.

· You will then see the following window. In the Short name: box, enter the name of the ATL object that you wish to create. The other boxes will fill in by themselves. In this case, we chose the name ComDllRes. Don’t chose “IOResource” because it’s already used by the system and it will prevent you from building the COM exe.

Also, take note of the name in Prog ID: In this case ComDll2.ComDllRes (dll name followed by the short name). This will be used as an entry in the Wrts options.

· In the list of attributes, as shown below, all defaults can be acceptable. You may want to add the option of Support IsupportErrorInfo as seen below. These options make more sense for those that are familiar with COM.

· Click on OK.

· If you get the following window:

· Click on Yes. If not, just proceed.

· Now we are back to the Studio.

· Now you need to link the project to an interface, which in this case relates to the Wrts capabilities. In the workspace, you should right-click on the Class that starts with C<short name>, where short name is from the ATL Object Wizard Properties. In our case CComDllRes as seen below.

· After right clicking on CComDllRes, Select Implement interface…

· You will get the following message and then click on OK.

· In the event that you see the following image instead of the previous one, press AddTypelib…

· Select the RtsIO for Wrts input-output library and then click on OK. If you do not see RtsIO, it’s because you are using a version of the TYX Stutio that is older than 1.10.x.

· In the following window, you need to check IIOResouce and then click on OK. You may chose to select at this time both IIOResource and IBinaryResource, but it may cause problems.

· If you get an error message:

· Close the project. Delete the Debug folder, and any of the files that may be present with the following extensions: ncb, opt, plg, aps and clw and try again.

· You need to repeat this for IBinaryResource (for text IO resources) if you haven’t done so already, by repeating the steps above starting at right-clicking on CComDllRes.

· If you are still having problems trying to add the interfaces, you can make sure that the ComDllRes.h contains the content of the file below.

· Now you will need to modify the source of what has been made available to you. In our case, double click on CComDllRes, or C<short name> as shown below:

// ComDllRes.h : Declaration of the CComDllRes

#ifndef __COMDLLRES_H_

#define __COMDLLRES_H_

#include "resource.h" // main symbols

#import "c:\usr\tyx\com\rtsio.dll" raw_interfaces_only, raw_native_types, no_namespace, named_guids

/////////////////////////////////////////////////////////////////////////////

// CComDllRes

class ATL_NO_VTABLE CComDllRes :

public CComObjectRootEx<CComSingleThreadModel>,

public CComCoClass<CComDllRes, &CLSID_ComDllRes>,

public ISupportErrorInfo,

public IDispatchImpl<IComDllRes, &IID_IComDllRes, &LIBID_COMDLL2Lib>,

public IBinaryResource,

public IIOResource

{

public:

CComDllRes()

{

}

DECLARE_REGISTRY_RESOURCEID(IDR_COMDLLRES)

DECLARE_PROTECT_FINAL_CONSTRUCT()

BEGIN_COM_MAP(CComDllRes)

COM_INTERFACE_ENTRY(IComDllRes)

COM_INTERFACE_ENTRY(IDispatch)

COM_INTERFACE_ENTRY(ISupportErrorInfo)

COM_INTERFACE_ENTRY(IBinaryResource)

COM_INTERFACE_ENTRY(IIOResource)

END_COM_MAP()

// ISupportsErrorInfo

STDMETHOD(InterfaceSupportsErrorInfo)(REFIID riid);

// IComDllRes

public:

// IBinaryResource

STDMETHOD(Read)(LONG lType, VARIANT * pVal)

{

if (pVal == NULL)

return E_POINTER;

return E_NOTIMPL;

}

STDMETHOD(Write)(LONG lType, VARIANT val)

{

return E_NOTIMPL;

}

// IIOResource

STDMETHOD(Open)(BSTR bstrName, LONG lMode)

{

return E_NOTIMPL;

}

STDMETHOD(Close)()

{

return E_NOTIMPL;

}

STDMETHOD(Flush)()

{

return E_NOTIMPL;

}

STDMETHOD(Abort)()

{

return E_NOTIMPL;

}

STDMETHOD(Seek)(LONG lOffset, SHORT sOrigin)

{

return E_NOTIMPL;

}

STDMETHOD(get_name)(BSTR * pVal)

{

if (pVal == NULL)

return E_POINTER;

return E_NOTIMPL;

}

STDMETHOD(get_Mode)(LONG * pVal)

{

if (pVal == NULL)

return E_POINTER;

return E_NOTIMPL;

}

STDMETHOD(get_Size)(LONG * pVal)

{

if (pVal == NULL)

return E_POINTER;

return E_NOTIMPL;

}

STDMETHOD(get_Position)(LONG * pVal)

{

if (pVal == NULL)

return E_POINTER;

return E_NOTIMPL;

}

STDMETHOD(get_Eof)(VARIANT_BOOL * pVal)

{

if (pVal == NULL)

return E_POINTER;

return E_NOTIMPL;

}

STDMETHOD(get_State)(LONG * pVal)

{

if (pVal == NULL)

return E_POINTER;

return E_NOTIMPL;

}

};

#endif //__COMDLLRES_H_

For complete information on each one of those functions, please refer to the TYX website or the updated online help.

· What you will want to do first, is to change the exit code for all of those functions, from E_NOTIMPL which is the return for “Error, not implemented”, to S_OK for an ok return value.

For example: For the Open and Close functions, you will get:

STDMETHOD(Open)(BSTR bstrName, LONG lMode)

{

return S_OK; // Changed

}

STDMETHOD(Close)()

{

return S_OK; // Changed

}

Those particular functions are called by the Wrts upon loading and unloading the dll with the Wrts. This is where you would put the code that you wish to see executed when the Wrts loads and unloads an Atlas program.

· You will also want to delete the following line on line 16 or 17:

public IIOResource

in order to avoid compilation problems. Make sure that you also delete the comma at the end of line 16 if public IIOResource is on line 17.

You will also want to return an end of file true statement in the get_Eof method:

STDMETHOD(get_Eof)(VARIANT_BOOL * pVal)

{

if (pVal == NULL)

return E_POINTER;

*pVal = VARIANT_TRUE; // Added

return S_OK; // Changed

}

· At the end of the CComDllRes class definition, you need to make the dialog a member variable so that it can be accessible throughout the resource. One place to put it would be on line 116.

CComDllDlg theDlg;

For the above to build properly, you then need to include the header file that has the definition for the class above. On line 7, you should now add this include:

#include "ComDllDlg.h"

· The code below is where the binary input and output are being handled. Some code has been added in order to achieve the goal that we have set ourselves in this example, which is to pass on and retrieve an integer. Typically, you will implement your own code as a function of your own requirements:

// IBinaryResource

STDMETHOD(Read)(LONG lType, VARIANT * pVal)

{

if (pVal == NULL)

return E_POINTER;

pVal->vt = VT_I4; // Added

pVal->lVal = (int)theDlg.IsDlgButtonChecked(IDC_CHECK1); // Added

return S_OK; // Changed

}

STDMETHOD(Write)(LONG lType, VARIANT val)

{

if(val.lVal == 1) // Added

theDlg.CheckDlgButton(IDC_CHECK1, BST_CHECKED); // Added

else if (val.lVal == 0) // Added

theDlg.CheckDlgButton(IDC_CHECK1, BST_UNCHECKED); // Added

else // Added

return E_FAIL; // Added

return S_OK; // Changed

}

At this point, if you want to refer to the dialog object, you need to use theDlg. That will give you access to the methods associated to the dialog Class.

pVal->vt will set the type of the variant to an integer. The following line will retrieve the information whether the button is checked or not and set the variant equal to it.

In Write, we retrieve the dialog object for the window the exact same way, by using theDlg. The following lines check the button as a function of what is passed on by the Atlas.

There are naturally different ways to do the same thing, and this is only one of them.

The Output on the other hand will display the content of the output string from the Atlas.

· If you wish to see the window appear when loading an Atlas project and disappear when unloading it, you need to go into the ComDllRes.h file and:

Change the code for the Open and Close function to the following code:

STDMETHOD(Open)(BSTR bstrName, LONG lMode)

{

AFX_MANAGE_STATE(AfxGetStaticModuleState()); // Added

BOOL ret = theDlg.Create(IDD_DIALOG1, NULL); // Added

if (!ret) // Added

AfxMessageBox("Error creating TM_Button Dialog"); // Added

theDlg.ShowWindow(SW_SHOW); // Added

return S_OK; // Changed

}

STDMETHOD(Close)()

{

theDlg.DestroyWindow(); // Added

return S_OK; // Changed

}

For open, it is a good idea to use the AFX_MANAGE_STATE command for clean code. This is necessary in the event that you use MFC as a shared library and not a static one.

Then, the object is created and then displayed. Open is called when the Altas program is loaded.

Close is called when the Atlas program is unloaded. For clean code, you want to destroy the object at this point.

· You are now ready to build the exe with the option Build/Build, by using the icon bar, or by pressing F7.

· Note for advanced users: If you are not an advanced COM user, you may skip this note.

If you want to make use of more than one IO resource, such as text and binary, you may have a compilation problem unless you correct some code.

In the file <Short Name>.h from the ATL Object Wizard Properties, ComDllRes.h in our case, in the COM_MAP section, you may have an uncertainty about the mapping between the IIOResource and the resource that you want to use.

In our case, you will have the code below:

BEGIN_COM_MAP(CComDllRes)

COM_INTERFACE_ENTRY(IComDllRes)

COM_INTERFACE_ENTRY(IDispatch)

COM_INTERFACE_ENTRY(ISupportErrorInfo)

COM_INTERFACE_ENTRY(IBinaryResource)

COM_INTERFACE_ENTRY(IIOResource)

END_COM_MAP()

If you had another resource such as text, you will have to tell IIOResouce which resource to use in order to satisfy the compiler. To do that, you will need to change the COM_INTERFACE_ENTRY for IIOResource to the line below.

BEGIN_COM_MAP(CComDllRes)

COM_INTERFACE_ENTRY(IComDllRes)

COM_INTERFACE_ENTRY(IDispatch)

COM_INTERFACE_ENTRY(ISupportErrorInfo)

COM_INTERFACE_ENTRY2(IIOResource, IBinaryResource) // Necessary to point to the

// desired class since there are two of them (Text and Binary).

COM_INTERFACE_ENTRY(ITextResource)

COM_INTERFACE_ENTRY(IBinaryResource)

END_COM_MAP()

That will ensure that your code will build properly, and you may then make use of both IO resource types.

This is the following code in ComDllRes.h that will do that.

1.3 What is wrong and how to fix it?

1.3.1 How to move the ComDll2.dll?

You will need to reregister the exe manually.

To do this, you need to go into a DOS window, move up to the subdirectory where the Proj6.exe is and execute the following command:

regSvr32 ComDll2.dll or in any other case regSvr32 <your project>.dll

Please note that for Win98, regsvr32 is not accessible from anywhere. You will need to add the path to Regsvr32 and if necessary the path for the dll also.

For NT, regsvr32 can be invoked from anywhere.

To unregister the Dll, you will want to use:

regSvr32 /u ComDll2.dll

2 What to do in the TYX Studio?

· At this point, you will need to have an Atlas program that makes use of that COM resource and to setup the Wrts in order to link that Atlas IO device to you COM dll.

2.1 Sample for Atlas 416:

Note: The version of the Atlas 416 has to be high enough to include the INPUT and OUTPUT commands. Earlier versions of 416 Atlas do not include those commands.

001000 BEGIN, ATLAS PROGRAM 'BUTTONS' $

001010 REQUIRE, 'TM_BUTTON', I-O DEVICE,

CAPABILITY,

FILE-SIZE 80 WORDS $

C $

001020 DECLARE, INTEGER, STORE, 'TM1' $

001025 DECLARE, INTEGER, STORE, 'I' $

001030 DECLARE, INTEGER, STORE, 'TMSTATUS' $

C $

E010000 DISPLAY, MESSAGE, *********** THE START ***************

DISPLAY, MESSAGE, *********** OUTPUT ******************

010010 CALCULATE, 'TM1' = 1 $

010020 OUTPUT, USING 'TM_BUTTON', ('TM1') $

DISPLAY, MESSAGE, 'BUTTON ON'

WAIT FOR, 1 SEC BEFORE STEP 010030 $

010030 CALCULATE, 'TM1' = 0 $

010040 OUTPUT, USING 'TM_BUTTON', ('TM1') $

DISPLAY, MESSAGE, 'BUTTON OFF'

WAIT FOR, 1 SEC BEFORE STEP 010050 $

010050 CALCULATE, 'TM1' = 1 $

010060 OUTPUT, USING 'TM_BUTTON', ('TM1') $

DISPLAY, MESSAGE, 'BUTTON ON'

WAIT FOR, 1 SEC BEFORE STEP 010070 $

C $

010070 CALCULATE, 'TM1' = 1 $

010080 OUTPUT, USING 'TM_BUTTON', ('TM1') $

DISPLAY, MESSAGE, *********** INPUT *******************

FOR, 'I' = 1 THRU 5 BY 1, THEN $

010090 INPUT, USING 'TM_BUTTON', 'TMSTATUS' $

010100 DISPLAY, MESSAGE, TMSTATUS -$

DISPLAY, RESULT, 'I' $

DISPLAY, MESSAGE, /5 - = $

010110 DISPLAY, RESULT, 'TMSTATUS' $

010120 DISPLAY, MESSAGE, -Press Manual intervention to continue-

WAIT FOR, MANUAL INTERVENTION $

END, FOR $

010190 DISPLAY, MESSAGE, *********** THE END ******************

010200 TERMINATE, ATLAS PROGRAM 'BUTTONS' $

This atlas will simply demonstrate two things:

It will output updated status of the button from checked to unchecked and vice-versa, and it will retrieve the status of the button in the Atlas via a Binary IO resource.

You can note that for IEEE416 Atlas, you may use the same COM resource for input and output only with newer versions of 416 and only with a Binary IO.

You will need to compile this Atlas and have it ready to run.

2.2 Sample for Atlas 716-89/95:

001000 BEGIN, ATLAS PROGRAM 'BUTTONS' $

10 DECLARE, VARIABLE, 'TXT_DATA' IS STRING(80) OF CHAR $

12 DECLARE, VARIABLE, 'OUT' IS FILE OF UNTYPED $

C $

20 DECLARE, VARIABLE, 'TM1' IS INTEGER $

25 DECLARE, VARIABLE, 'I' IS INTEGER $

30 DECLARE, VARIABLE, 'TMSTATUS' IS INTEGER $

C $

E010000 OUTPUT, C'*********** THE START ***************' $

10 OUTPUT, C'\LF\*********** OUTPUT ******************' $

C $

11 CALCULATE, 'TM1' = 1 $

12 ENABLE, I-O NEW C'TM_BUTTON', VIA 'OUT' $

22 OUTPUT, TO 'OUT', 'TM1' $

25 OUTPUT, C'BUTTON ON' $

32 WAIT FOR, 1 SEC $

35 CALCULATE, 'TM1' = 0 $

45 OUTPUT, TO 'OUT', 'TM1' $

48 OUTPUT, C'BUTTON OFF' $

55 WAIT FOR, 1 SEC $

57 CALCULATE, 'TM1' = 1 $

65 OUTPUT, TO 'OUT', 'TM1' $

70 OUTPUT, C'BUTTON ON' $

75 WAIT FOR, 1 SEC $

C $

77 CALCULATE, 'TM1' = 1 $

85 OUTPUT, C'\LF\*********** INPUT *******************'

95 FOR, 'I' = 1 THRU 5 BY 1, THEN $

97 INPUT, FROM 'OUT', INTO 'TMSTATUS' $

010100 OUTPUT, C'TMSTATUS ---', 'I', C'/ 5 --- =', 'TMSTATUS' $

20 OUTPUT, C'Press TRUE or FALSE to continue...\LF\' $

30 INPUT, GO-NOGO $

40 END, FOR $

50 DISABLE, 'OUT' $

90 OUTPUT, C'*********** THE END ******************' $

C $

010200 TERMINATE, ATLAS PROGRAM 'BUTTONS' $

This atlas will simply demonstrate two things:

It will output updated status of the button from checked to unchecked and vice-versa, and it will retrieve the status of the button in the Atlas via a Binary IO resource. The resource will be visible after is has been enabled and will close when it is disabled.

You will need to compile this Atlas and have it ready to run.

2.3 Wrts Settings:

· Now that the Atlas is ready to run, you should launch the Wrts.

· Go into Control/Options…

· Now Click on RTS Property Pages and select the IOSubsystem tab

· You now need to create the link between your Atlas IO resource and the COM resource that you wish to link to. Go into the list of Resource Names. If TM_BUTTON is already there with an unknown ProgID, remove it by selecting it and by pressing Remove.

· Press Add and you will see the following window:

The Resource name is the one that you have defined in your Atlas. In our case TM_BUTTON.

Your ProgID will be the one that you will have remembered from Atlas Object Wizard Properties in the previous task of generating the COM exe source.

In this case, you will want to use ComDll2.ComDllRes:

· Click on OK on this window. Both of the entries will appear in the Server Property Pages Properties.

· If this step fails, you need to make sure that the I\O resource exe (ComDll2 in this case) is registered before trying again. Your Wrts is now ready to link your Atlas IO resource to your COM dll.

Note: The effect will take place the next time you will reopen the Wrts, so close the Wrts and reopen it.

You may now run the Atlas program and the COM dll will be invoked when necessary. The location of the COM dll does not matter because it has been registered in your system.

3 How to debug the Com dll?

· First, you put the breakpoints where you want them in your dll COM source code. You would now run the COM dll in debug mode from MSVC++ by going into Build/Start debug/Go or by pressing F5.

· Now you would go into the TYX studio and run the Wrts.

The run time system would execute until it used the IO Com dll that you have running in debug mode. The execution of the Wrts would stop at your breakpoints in the COM dll source.