Is binary compatibility so important?


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Thread: Is binary compatibility so important?

  1. #1
    Michael G. Guest

    Is binary compatibility so important?


    Hi!

    When all calls to COM objects maintained through ProgIds, e.g. "Component.Method",
    is binary compatibility which maintains continuous GUIDs important? Every
    time new component is installed it will register the ProgId with proper GUID.
    Why to preserve binary compatibility?

    Thaks in advance,
    Michael

  2. #2
    K.Poongundran Guest

    Re: Is binary compatibility so important?


    Hi,
    Call to COM objects are maintained by ProgID ->ClassID. So if you don't put
    binary compatibility every time a new ClassID is assigned to the ProgID.
    So your ProgID cannot identify the old ClassID. So You need to Re-register
    the Component and you need to re compile all the programs whether it is a
    normal exe or an activeX dll for your ProgID to identify.

    Have a nice day!
    Krish Poongundran

    "Michael G." <michaelg@pos.co.il> wrote:
    >
    >Hi!
    >
    >When all calls to COM objects maintained through ProgIds, e.g. "Component.Method",
    >is binary compatibility which maintains continuous GUIDs important? Every
    >time new component is installed it will register the ProgId with proper

    GUID.
    >Why to preserve binary compatibility?
    >
    >Thaks in advance,
    >Michael



  3. #3
    Michael Culley Guest

    Re: Is binary compatibility so important?


    Michael,

    If you have a component that is used by several apps, which could be updated
    by installing a different app, then binary compatability is vital.

    But if you have a component that is specific to your app then it is optional.
    But you must always distribute the exe and the component together and not
    use it in any other apps.

    Michael Culley

    "Michael G." <michaelg@pos.co.il> wrote:
    >
    >Hi!
    >
    >When all calls to COM objects maintained through ProgIds, e.g. "Component.Method",
    >is binary compatibility which maintains continuous GUIDs important? Every
    >time new component is installed it will register the ProgId with proper

    GUID.
    >Why to preserve binary compatibility?
    >
    >Thaks in advance,
    >Michael



  4. #4
    Colin McGuigan Guest

    Re: Is binary compatibility so important?

    Michael G. <michaelg@pos.co.il> wrote in message
    news:3a23695e$1@news.devx.com...
    >
    > Hi!
    >
    > When all calls to COM objects maintained through ProgIds, e.g.

    "Component.Method",
    > is binary compatibility which maintains continuous GUIDs important? Every
    > time new component is installed it will register the ProgId with proper

    GUID.
    > Why to preserve binary compatibility?
    >
    > Thaks in advance,
    > Michael


    _If_ all calls are maintained through ProgIDs, then, no, binary
    compatibility isn't important.

    However...

    You must always make sure that, when updating the DLL, you reregister.
    ProgID lookup is done in the registry, where a ProgID is matched up to a
    GUID. If you overwrite a DLL with one that has different GUIDs, but don't
    register it (so it doesn't update the registry), COM won't be able to create
    the object.

    --
    Colin McGuigan




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