If I have the code as shown at the end of the mail, i get

project1.lpr(6,9) Warning: Function result variable does not seem to
initialized

but how can I initialize it?

**** Unit1
unit Unit1;  {$mode objfpc}{$H+}
interface
uses  Classes, SysUtils;
type
   TBar = object
   private
     a: integer;
   public
     procedure Init;
   end;
implementation
procedure TBar.Init;
begin
   a := 0;
end;
end.

**** main program

program Project1;
uses Unit1;
function Foo: TBar;
begin
   Result.Init;
end;
begin
   Foo;
end.

Sorry if I overlooked something, but where is the variable of that type declared in your code? These objects may be either declared statically ("var B: TBar") or dynamically ("Result := New (TBar.Init)" - but then the return value must be of type PBar, not TBar). If I understand it correctly, you initialize the object on the stack, but it would disappear from there (gets overwritten) immediately after the function return (the following function call would overwrite it).

Tomas

Tomas Hajny wrote

Sorry if I overlooked something, but where is the variable of that type declared in your code? These objects may be either declared statically ("var B: TBar") or dynamically ("Result := New (TBar.Init)" - but then the return value must be of type PBar, not TBar).

Objects are like (advanced) records.

So Result is a TBar, and result already has the memory it needs. "New" is not needed.

It gets lost only, because i do not use the result of the function call.
But even if D did "SomVarBar := Foo;", I still get the warning.

Why is it old style, if you use mode objfpc?

Vincent

The warning is wrong.

Jonas

Vincent Snijders wrote

Why is it old style, if you use mode objfpc?

I did just look for a word, that would help distinguish it from TObject/class

Afaik "object" existed before class?

Result is stored in a temporarily allocated memory. You are right that New is not absolutely needed (as witnessed by the compiler accepting your code
- unlike TP/BP which wouldn't accept TBar as return value, because it doesn't support performing assignment on objects or even records), but using the temporarily allocated memory implies that you initialize the memory in one place first (Init) and then you need to copy the data to another memory location afterwards. Depending on the object size, this may or may not be an issue, but it doesn't look like the most efficient solution to me in any case.

Yes. Still, if the (formally incorrect) warning helps in pointing out that the chosen solution may not be the most efficient one, it isn't so bad from my point of view. ;-)

Tomas