[fpc-devel] TComponent.Tag type

[Marc Weustink]

Graeme Geldenhuys wrote:
>> This has been discussed before:
>>  http://www.mail-archive.com/fpc-devel@lists.freepascal.org/msg05895.html
>>
>>  It could be problematic if a Tag is streamed and read on different platforms. It
>>  would better to introduce a new (non streamable) SizeInt property.
>>
> 
> In fpGUI I introduced the following...
> 
>   public
>     property  TagPointer: Pointer read FTagPointer write FTagPointer;
> 
> 
> Non-streamable, but handy.  Would that work?


At work I completely abanonded putting pointers in tags, but I use a Map 
like object inbetween:

on create:
SomeObject.Tag := GetnextTagSequence;
ObjectMap.Add(someObject.Tag, someObject);

on use:
if ObjectMap.GetData(someObject.Tag, someObject) then
   someObject.dosomething

On destroy of SomeObject is is removed form the map. Advantage is that 
if the tag is passed to different routines, if the map cant find the 
object, it is destroyed, so you never reference a destroyed object.

Marc