I'm just looking for confirmation of my realization that CONST/VAR is useful also for TArray method parameters (not just strings) - before I start changing all my TArray parameters to include CONST or VAR (if changes are needed).

I'm just looking for confirmation of my realization that CONST/VAR is useful also for TArray method parameters (not just strings) - before I start changing all my TArray parameters to include CONST or VAR (if changes are needed).

To some extent, I understand the difference between array of T and TArray. And I thought that changing from open array parameters to TArray, is a benefit on it's own. Since TArray is a pointer, and array of T actually copies copies the values to parameter.

But looking into CPU code, there is a big difference between TArray parameters, non-const, var and const:

This code:

TCarBrand = record
Id: integer;
BrandName: string;
BrandStr: string;
end;

var
Form2: TForm2;
gVal: integer;
myArray: TArray;

implementation

{$R *.dfm}

procedure Test1(aArray: TArray);
begin// Test1
gVal := aArray[1].Id;// Test1
end;// Test1

procedure Test2(var aArray: TArray);
begin// Test2
gVal := aArray[1].Id; // Test2
end;// Test2

procedure Test3(const aArray: TArray);
begin// Test3
gVal := aArray[1].Id;// Test3
end;// Test3

procedure TForm2.Button1Click(Sender: TObject);
begin
SetLength(myArray,1);
test1(myArray);
test2(myArray);
test3(myArray);
end;

generates CPU instructions on included image.

So, leaving TArray parameter without CONST or VAR is wasting a lot of resources, correct?