2016-07-28 12:40 GMT+02:00 Michael Van Canneyt <mich...@freepascal.org>:
> I don't see how you can solve nullable var parameters in native code.
>
I'd like to present how TNullable<T> works in my implementation (compilable
and runable program ;)
=== code begin ===
procedure Test1(var x: Integer);
begin
x := 1;
end;
procedure Test2(var x: TNullable<Integer>);
begin
x := 2;
end;
var
a: TNullable<Integer>;
begin
try
WriteLn(a.Value);
except
on E: EAccessViolation do
WriteLn(a.HasValue); // print false
end;
a := 0;
WriteLn(a.HasValue); // print true
if a.HasValue then
begin
WriteLn(a.Value); // print 0
WriteLn(a^); // print 0
end;
Test1(a^);
WriteLn(a.Value); // print 1
Test2(a);
WriteLn(a.Value); // print 2
end.
=== code end ===
--
Best regards,
Maciej Izak
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