Const in function params

[msd 5]

Hello, 

 

If I want to set all params of Delphi function to be const (because of small amount of memory) do I need to define it as:

 

function FnName(const varA: string; const varB: integer; const varC: boolean = false): boolean;   OR    function FnName(const varA: string; varB: integer; varC: boolean = false): boolean; 

 

Thanks in advance...

 

[Brandon Staggs 275]

The first, because in the latter, you are saying the first parameter is const but the others are going to get local copies.

 

Also, for strings, there is no memory issue here you are solving. I really doubt any memory issue can exist with integer or boolean parameters. If so, probably you need to look at some kind of data structure you pass by reference.

 

Strings are copy-on-write. In this case you are just telling the compiler not to allow setting a new value to the string in that function. You are just preventing the reference count from being incremented at the beginning of the function call, you are not changing how the compiler passes the string reference.

Edited February 8, 2023 by Brandon Staggs

[programmerdelphi2k 237]

I think that better way would be read the EMB explains

https://docwiki.embarcadero.com/RADStudio/Sydney/en/Parameters_(Delphi)

 

after, this... each case it's a case (in special case)