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__vfInit in Element Collections Example

  • asnik

    asnik - 2020-09-20

    Hello, i am unable to compile Element Collections Example because Codesys (3.5.10,, does not recognize pInstance^.__vfInit();
    __in MyElementFactory.Create with C0004 and C0046 errors.
    What could be the reason?

  • i-campbell

    i-campbell - 2020-09-20

    Are they just precompile errors? It should still compile.

  • asnik

    asnik - 2020-09-20

    Yes, indeed, thanks!

  • michaelADE

    michaelADE - 2021-06-17

    Hey, I know that this is an old topic, but was useful to me too knowing this error wouldn't actually prevent the system from running.

    However, this means that there is now always an error in my code. is there any way to hide this error? I have found there is the {warning disable} command but it doesn't appear to work for errors.

  • rlie

    rlie - 2022-11-24


    It seems that with {implicit on} it is managed by the compiler.


    Last edit: rlie 2022-11-24
  • Strucc.c

    Strucc.c - 2022-11-26

    Interesting topic... Can we please get an update or a little bit more explanation of these former system calls - used mostly by library developers?

    As far as I understand, __vfInit() is to be called on "typed" pointers, typically on pointers to function block types, to execute the init sequence, ie. variable initialization.

    So... in theory all 3 alternatives should work the same:


        // Static declaration
        E0      :   FB_TEST;
        // Dynamic declaration to be used by __NEW()
        pE1     :   POINTER TO FB_TEST;
        E1      :   REFERENCE TO FB_TEST;
        // Dynamic declaration
        pE2     :   POINTER TO FB_TEST;
        E2      :   REFERENCE TO FB_TEST;
        xInit   :   BOOL := TRUE;
        RES     :   RTS_IEC_RESULT;


    IF xInit THEN
        // This requires "dynamic memory allocation" option in the application
        pE1 :=  __NEW(FB_TEST);
        E1  REF=    pE1^;
        pE2     :=  SysMem.SysMemAllocData('FB_ENTRY Whatever', SIZEOF(FB_TEST), ADR(RES));
        {implicit on}
        pE2^.FB_Init(TRUE, FALSE);
        {implicit off}
        E2  REF=    pE2^;
        xInit := FALSE;

    1. Is this still correct to use vfInit() in library development (so that it doesn't depend on "Dynamic memory allocation" )?
    2. Is it OK to use SysMem, or is there a better wrapping platform for such purpose? (also from the library development aspect)


    Last edit: Strucc.c 2022-11-26

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