How to call a dll file of windows using SAP ABAP

In ABAP language exists many forms to connect and i want explain how to call dll files for Windows

Below follow step by step to construction:

1 – Create the dll files. In my example i am using the visual basic language, but you can use another language of programmer (ex.: Delphi, C# etc)

VERSION 1.0 CLASS  
BEGIN    MultiUse = -1  'True    Persistable = 0  'NotPersistable    DataBindingBehavior = 0  'vbNone    DataSourceBehavior  = 0  'vbNone    MTSTransactionMode  = 0  'NotAnMTSObject  
END  
Attribute VB_Name = "DLL_VB"  
Attribute VB_GlobalNameSpace = False  
Attribute VB_Creatable = True  
Attribute VB_PredeclaredId = False  
Attribute VB_Exposed = True  
' Declaration of variable return
Private s_retorno As String  
Public Property Get retorno() As String        retorno = "retorno: " & s_retorno  
End Property  
' Function that receives the command and variable playing in s_retorno
Public Function envia_comando(ByRef s_comando As String)      s_retorno = s_comando  
End Function  

1.1 - Afterbuilding the DLLyou need to registerin windows using the command:

                regsvr32 <name file>.dll

  After this you are should look the pop-up with message:

2 - Execute the program regedit.exe in Windows System and find the name of DLL file

You need find two values in regedit.exe.

CLsid : {2EC47E73-2E05-45BA-AC8B-CD7E798D4034}

TypeLib: {4F4B5B12-5F45-43DB-A06E-2065395F9866}

3 - This values do you must put in transaction SOLE

4 - Below the example in SAP ABAP that call dll file in Windows.

This example: send a string and return another string using the file dll

*"----------------------------------------------------------------------
*"*"Interface local:
*"  IMPORTING
*" VALUE(I_COMANDO) TYPE  CHAR20 OPTIONAL
*"  EXPORTING
*" VALUE(E_RETORNO) TYPE  CHAR20
*"  EXCEPTIONS
*" CREATE_OBJECT_ERROR
*" GET_PROPR_ERROR
*"      CALL_ERROR
*" FREE_OBJ_ERROR
*"----------------------------------------------------------------------
* Includes  INCLUDE ole2incl.
* Global Variables  DATA: obj_vb TYPE ole2_object,        vg_comando(20) TYPE c,        vg_retorno(20) TYPE c.
* sends the command to the dll  vg_comando = I_COMANDO.
* Creating the object to use the DLL  CREATE OBJECT obj_vb 'TESTDLL'.  IF sy-subrc NE 0.    RAISE create_object_error.  ENDIF.
* Sending the command to the dll  CALL METHOD OF obj_vb 'envia_comando' EXPORTING #1 = vg_comando.
* Receiving command of dll  get property of obj_vb 'RETORNO' = vg_retorno.  IF sy-subrc NE 0.    RAISE get_propr_error.  ELSE.    E_RETORNO = vg_retorno.  ENDIF.
* Deallocates the object memory  FREE OBJECT obj_vb.  IF sy-subrc NE 0.    RAISE free_obj_error.  ENDIF.

ENDFUNCTION.

I have helped, any questions please send a message.

Regards

Marcelo Macedo