[Lazarus] Synchronize problem in linux

[Mattias Gaertner]

On Wed, 25 May 2011 12:22:53 +0200 (CEST)
michael.vancanneyt at wisa.be wrote:

> 
> 
> 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.

Ehm, he made sure that only one thread accesses the TStringList at a
time.
Why should TMultiReadExclusiveWriteSynchronizer be necessary?

Mattias