[Lazarus] Synchronize problem in linux

[michael.vancanneyt at wisa.be]

On Wed, 25 May 2011, Giuliano Colla wrote:

> Mattias Gaertner ha scritto:
>> This might help:
>> http://wiki.lazarus.freepascal.org/Multithreaded_Application_Tutorial
>> 
>> Mattias
>>
>> 
> I have a question related to this subject. Working with Borland's stuff 
> (Kylix) I stumbled into a problem, and I'd like to know if the same applies 
> also to Lazarus.
>
> I had a multithread application with a thread which receives data through a 
> communication line. I thought it safe to use a TStringList, which AFAIK is 
> not a visual object. The main thread would create the StringList, the other 
> thread would append strings to the list, and when it was done, the main 
> thread would perform the required processing. The logic of the application 
> itself made it sure that there was no conflict whatsoever. It turned out that 
> it didn't work at all, silently filling with garbage the List, and I was 
> forced to move all code related to the StringList in the main thread, with a 
> slight overhead which, IMO should not have been necessary. I couldn't 
> understand if it was a Kylix bug or a feature.
>
> How would Lazarus behave with respect to this scenario? The scheme I 
> described is expected to work?

No. You should use a TMultiReadExclusiveWriteSynchronizer object to
synchronize access to your object, or use a critical section.

Michael.