Dear all,
I'm testing FPC-trunk and I'm especially interested in using anonymous functions because they should simplify working with TThread.Synchronize and others a lot.
I stumbled upon an issue which I'd like to post here first because I am not sure whether it's a bug or just a wrong usage on my side.
Here's a small example:
program project1;
{$modeswitch anonymousfunctions}
{$modeswitch functionreferences}
uses Classes, EventLog, SysUtils;
type
TTest = class
FOnLog: TLogMessageEvent;
procedure CallOnLog (AEventType: TEventType; AMessage: String);
end;
procedure TTest.CallOnLog (AEventType: TEventType; AMessage: String);
var
r: reference to TThreadMethod = nil;
m: TThreadMethod = nil;
begin
// This doesn't work because the anonymous procedure is
// capturing local symbols. I understand that this doesn't work.
m := procedure
begin
FOnLog (Self, AEventType, AMessage);
end;
// As far as I have understood
// https://forum.lazarus.freepascal.org/index.php/topic,59468.0.html
// the solution should be to use a "reference to".
// In fact, assignment works as expected:
r := procedure
begin
FOnLog (Self, AEventType, AMessage);
end;
// But I seem not to have any change to pass the reference.
// Both versions fail:
TThread.ForceQueue (NIL, r());
TThread.ForceQueue (NIL, @r);
end;
begin
end.As you can see, the goal is to call TThread.ForceQueue. Of course, the easiest solution was having an overloaded "TThread.ForceQueue (TThread, TThreadProcedure)" as is the case with Delphi. I have already posted a feature request on Github.
But I don't know why I can't use a "reference to TThreadMethod". If I understand the feature announcement correctly, this should work, shouldn't it?
Kind regards,
Thomas