8   References
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     It is important to distinguish between the different meanings of
     the word "reference."  In Clipper, there are two distinct kinds of
     references:

     1. An object reference (an OREF):  This is a special internal
        quantity that identifies the location of a character, array, or
        code block value in virtual memory.  Because these kinds of
        values can be very large, a VALUE cannot directly contain them.
        Instead, the VALUE contains an OREF that allows the data to be
        located when needed.  Whenever necessary, the system performs a
        de-referencing operation in order to convert an OREF into an
        actual memory address.

     2. A variable reference (a VREF):  Like an OREF, a VREF is a
        special internal quantity.  Instead of referring to a piece of
        data, however, a VREF refers to a Clipper variable.  A VREF is
        created whenever a variable is passed by reference in a function
        call or DO...WITH statement.  VREFs are special in that they
        only exist on the Eval Stack, and only as parameters during a
        function call.  A VREF cannot be assigned to a variable or
        stored in an array.

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        . Notes

        .  A bug in Clipper 5.0/5.01 allows a VREF to be assigned
           to a variable in certain cases.  This behavior is
           unintentional and will be eliminated in future releases.

        .  When dealing with C, the terminology of references
           becomes somewhat murky.  This is because C programmers often
           use the words reference and pointer interchangeably.  Where
           Clipper is involved, however, the two words have very
           distinct meanings.  A reference is one of the special
           quantities discussed above.  A pointer is an actual memory
           address or a C variable containing such an address.
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