[fpc-pascal] Get TMethod from function reference
pascaldragon at googlemail.com
Sat Sep 17 17:57:23 CEST 2022
Am 16.09.2022 um 03:53 schrieb Hairy Pixels:
>> On Sep 11, 2022, at 3:28 PM, Ondrej Pokorny via fpc-pascal <fpc-pascal at lists.freepascal.org> wrote:
>> You should be able to get the Invoke procedure pointer from the RTTI.
> Sorry Sven mentioned this I must have glossed over it. So yes I am storing the function reference in a class so it’s not going to get freed.
> Given this example here can you explain how to get the procedure pointer from the RTTI? Even so if you get the procedure pointer you need the class instance also, which reference must be keeping somewhere right?
> TProc = reference to procedure;
> TMyClass = class
> procedure DoThis;
> p: TProc;
> c: TMyClass;
> c := TMyClass.Create;
> p := c.DoThis;
> // Can I get the refefence to "c" back using the RTTI?
No, you can't get a reference to c, because the compiler will
essentially create the following code:
=== code begin ===
TProc = reference to procedure;
TMyClass = class
TCapturer = class(TInterfacedObject, TProc)
m: procedure of object;
procedure TProc.Invoke = Anonymous1;
capturer := TCapturer.Create;
capturer_keepalive := capturer;
c := TMyClass.Create;
capturer.m := @c.DoThis;
p := capturer as TProc;
=== code end ===
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