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Calling Visual studio Ver 6 DLL from Visual Studio 2015 RRS feed

  • Question

  • I have a question. I have a project which has all individual C++ DLL 's. The entry point is a C# DLL which in turn calls all these C++ DLL'S . Now the OS environment has be migrated to VS 2015 and Windows 10.

    I have a problem porting all these DLL's to VS 2015 as I do not have the complete source code. I was able to port the C# DLL.

    Can I deploy the Migrated C# DLL along with the old Visual studio Version 6 DLL's in the environment. The backward compatability should be able to take care of this. Can you please let me know your views. We can have a separate Include header file and Lib file path for these old c++ DLL. awaiting your reply.

    Wednesday, January 29, 2020 7:07 AM

All replies

  • Can some one please look into this and give their valuable input....Thanks
    Wednesday, January 29, 2020 8:38 AM
  • I have a question. I have a project which has all individual C++ DLL 's. The entry point is a C# DLL which in turn calls all these C++ DLL'S . Now the OS environment has be migrated to VS 2015 and Windows 10.

    I have a problem porting all these DLL's to VS 2015 as I do not have the complete source code. I was able to port the C# DLL.

    Can I deploy the Migrated C# DLL along with the old Visual studio Version 6 DLL's in the environment. The backward compatability should be able to take care of this. Can you please let me know your views. We can have a separate Include header file and Lib file path for these old c++ DLL. awaiting your reply.

    Since we have no information about the DLLs it is not possible to answer with absolute certainty.

    Also, remember that VS6 is over 20 years old and those DLLs were written to be compatible with versions of Windows that have been obsolete for a very long time.  You may find that the assumption of perfect backward compatibility no longer holds.

    The VS6 DLL's dependencies must be available in the new environment. 

    You already know the right answer, painful though it may be.  It's time to invest in updating to a modern version of VS and leave the VS6 binaries behind.

    Wednesday, January 29, 2020 10:44 AM
  • Thanks very much.

    Final last clarification...

    Alternatively. Can we write a Adapter Plugin in ATL/COM which calls the vc6  dll's.

    The  C# Application will work with this intermediate adaptor layer

    I will build the c++ DLL's linked statically to MFC in VC6.

    The ATL/Com adaptor developed in 2015   will load those DLLS's and export some methods.

    The c# application will call these methods.

    please let me know your thoughts...

    thanks an million...

    Thursday, January 30, 2020 2:07 PM
  • I will build the c++ DLL's linked statically to MFC in VC6.

    Earlier you wrote , "I have a problem porting all these DLL's to VS 2015 as I do not have the complete source code."  So how can you build the DLLs?

    Thursday, January 30, 2020 2:17 PM
  • Thanks for your quick response..

    I will re-use the same vc6 DLL  and Then try calling them from a ATL/COM Layer built in 2015. Finally this layer (Plugin) code will be used by the C#.NET Layer.  Please suggest..

    Thursday, January 30, 2020 2:40 PM
  • Managed code can call functions exported by unmanaged DLLs using P/Invoke.  The ATL/COM Layer may not be required.

    Does your Windows 10 environment contain all the dependencies that are needed by the VC6 DLLs?


    • Edited by RLWA32 Thursday, January 30, 2020 3:09 PM
    Thursday, January 30, 2020 3:03 PM