Delphi constants and references

I want to pass constant references to functions in delphi, so I am sure that the referenced object won't change and to save time and memory. So I want to declare a function like

function foo(var const Value : Bar) : Boolean;

however this is not allowed. I thought constant values would be automatically sent as references. However I found out that it is not the case (getting the address of an object befor开发者_Go百科e sending it to the function gives me $12F50C and the address of the same object inside the function is $12F564)

What can I do to send constant references?

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Function Foo(Const Value:Bar):Boolean passes the value in the "most efficient" way, for large objects this is usualy by reference but smaller objects tend to get passed by value.

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Note that passing a parameter marked as const doesn't mean it can't be changed, it just means the compiler won't let you directly change it.