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Regulat dll using MFC

Posted on 2001-07-06
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Last Modified: 2013-11-20
I have a legacy C application that can use dlls to extend its functionality.
I want to create a "Regular dll with MFC statically linked" project that exports one function. I want the function to contain a dialog that contains two input boxes that is displayed when my legacy application calls the exported function.
When I created the dll project the IDE created for me a file containing code as shown bellow.
I want where should I code the exported function.
How it would look like.
Inside the function how can I create the dialog box with the two input boxes.

Thank you

+++++++++++++++++++dll code created by the VS IDE+++++++// test.cpp : Defines the initialization routines for the DLL.
//

#include "stdafx.h"
#include "test.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

//
//     Note!
//
//          If this DLL is dynamically linked against the MFC
//          DLLs, any functions exported from this DLL which
//          call into MFC must have the AFX_MANAGE_STATE macro
//          added at the very beginning of the function.
//
//          For example:
//
//          extern "C" BOOL PASCAL EXPORT ExportedFunction()
//          {
//               AFX_MANAGE_STATE(AfxGetStaticModuleState());
//               // normal function body here
//          }
//
//          It is very important that this macro appear in each
//          function, prior to any calls into MFC.  This means that
//          it must appear as the first statement within the
//          function, even before any object variable declarations
//          as their constructors may generate calls into the MFC
//          DLL.
//
//          Please see MFC Technical Notes 33 and 58 for additional
//          details.
//

/////////////////////////////////////////////////////////////////////////////
// CTestApp

BEGIN_MESSAGE_MAP(CTestApp, CWinApp)
     //{{AFX_MSG_MAP(CTestApp)
          // NOTE - the ClassWizard will add and remove mapping macros here.
          //    DO NOT EDIT what you see in these blocks of generated code!
     //}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CTestApp construction

CTestApp::CTestApp()
{
     // TODO: add construction code here,
     // Place all significant initialization in InitInstance
}

/////////////////////////////////////////////////////////////////////////////
// The one and only CTestApp object

CTestApp theApp;
+++++++++++++++++++++++++++++++++++++++++++++++++++++++
0
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Question by:jc64
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8 Comments
 
LVL 86

Expert Comment

by:jkr
ID: 6260826
Well, as the comment in your code states:

Just put the function somewhere in the code, accoring to the specs of your legacy app

extern "C" <rettype> PASCAL EXPORT TheExportedFunction(<parameter list>)
{
  AFX_MANAGE_STATE(AfxGetStaticModuleState());
  // normal function body here
}

To make sure that the function is exported exactly the way you want (keeping the exat name without e.g. an underscore), additionally add a '.def' file to your project:

LIBRARY mydll
DESCRIPTION 'comment about all that'

EXPORTS

    TheExportedFunction
0
 
LVL 2

Expert Comment

by:MadYugoslav
ID: 6264249
If You use static linked MFC there are is no nedd to call MACRO AFX_MANAGE_STATE.
If you include definition file (.DEF) in your project there is no need to special declaration for exported function.
0
 
LVL 86

Expert Comment

by:jkr
ID: 6287007
jc64, are you still with us?
0
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Author Comment

by:jc64
ID: 6291092
jkr, I am sorry I was away for work and just came back.

First I increated the points to 300 as this is important to me. second here are the steps I took to write an MFC dll that exports one function that when called displays a dialog that contains two text boxes.

1 - Create a new porject "MFC AppWizard[dll]"
2 - Regular DLL with MFC Statically linked
  The IDE created  the following files.

  - Test.h
  - Test.cpp
  - Test.DEF

  * Test = project Name
I added the project a new Form using insert-New Form
  The IDE Created two files
  - DTest.h
  - DTest.cpp

  * DTest = Dialog Name


Now I don't know how to proceed after that.

I want to create a C program and call the exported function from the dll above as

#include "What ever header file is necessary from the dll"

main()
{
   CAllFunctionExportedfromTheDLL();
}

Please advice me as to how to proceed and change different files.


Thank you to waiting.
0
 
LVL 86

Accepted Solution

by:
jkr earned 1200 total points
ID: 6291106
Well, you mainly have it there - just add your code to 'Test.cpp'

extern "C" <rettype> PASCAL EXPORT TheExportedFunction(<parameter list>)
{
 AFX_MANAGE_STATE(AfxGetStaticModuleState());
 // normal function body here
}

and supply a separate header "What ever header file is necessary from the dll.h" - OK, just joking, let's call it 'thedll.h':

#ifdef __cplusplus
extern "C"
{
#endif
<rettype> PASCAL EXPORT TheExportedFunction(<parameter list>);
#ifdef __cplusplus
}
#endif

(the #ifdef stuff is necessary to not confuse the compiler in files with a '.c' extension)

Also, supply an entry for 'TheExportedFunction' in 'test.def', as shown above.

Then, compile the DLL and add the '.lib' file that is created to your C project, and it should work.
0
 

Author Comment

by:jc64
ID: 6291602
Jkr, I will try your suggestion and will get back to you as soon as finish.

Thanks
0
 

Author Comment

by:jc64
ID: 6291766
Jkr, I will try your suggestion and will get back to you as soon as finish.

Thanks
0
 
LVL 86

Expert Comment

by:jkr
ID: 6296539
Thanx, but you shouldn't accept an answer unless you really know that it works for you (though I have no doubt it will :o)
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