[Lazarus] Enqueuing a callback from a thread via other class - or am I overcomplicating this ?

[José Mejuto]

El 18/06/2017 a las 22:44, el es via Lazarus escribió:

> Hence the object, would have to have ITS callback routine be something 
> like a TNotifyEvent ( procedure(AObject: TSomeObject) of object, or 
> something), and the flag set is set when the callback returns to the 
> object context like
> 
> procedure TSomeObject.Callback;
> // this procedure is enQueue()d by the thread
> begin
>    if Assigned({Self.}FSomeObjectNotifyEvent) then
>      FSomeObjectNotifyEvent(Self);

Hello,

Just exit the procedure and there is not free problem. You will get an 
exception when you use object data, not object code.


procedure TSomeObject.Callback;
// this procedure is enQueue()d by the thread
begin
    if Assigned({Self.}FSomeObjectNotifyEvent) then
      FSomeObjectNotifyEvent(Self);
    Self.CanBeDestroyed := true;
    Exit;
end;

After you set CanBeDestroyed to true you must consider all data as 
RANDOM, so don't access any property or variable.

Remember that creating and destroying threads is very expensive in CPU time.

--