> On Jan 6, 2018, at 1:49 PM, Karoly Balogh (Charlie/SGR)
> <[email protected]> wrote:
>
> type
> PMyStruct = ^TMyStruct;
> TMyStruct = record
> some, fields: integer;
> next: PMyStruct;
> end;
>
> function MEMNEXT(x: Pointer): PMyStruct;
> begin
> MEMNEXT:=PMyStruct(PByte(x)-PByte(@(PMyStruct(nil)^.next)));
> end;
I’m curious about how this is intended to be used. What would the value of x
be? This looks like a confusing way to write sizeof(TMyStruct) -
Sizeof(pointer) but I’m confused myself.
Also why does @(PMyStruct(nil)^.next not crash? Dereferencing and taking the
addressing of a nil pointer sounds like a bad idea.
Regards,
Ryan Joseph
_______________________________________________
fpc-pascal maillist - [email protected]
http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
