[fpc-devel] ref count types / threadsave question

Jonas Maebe jonas at freepascal.org
Sun Jan 6 15:00:44 CET 2019

On 06/01/19 14:42, Martin Frb wrote:
> Btw about threads seeing different cached versions of data.
> What happens in case of synchronize?

Synchronize uses an RtlEvent. That one uses OS primitives that include 
memory barriers, so the data will be properly synchronised across cores.

> If so then how to I ever get a managed variable safely into a thread? 
> (Once the thread was started).

It behaves the same as any other data.

In general: always use an RTLEvent, mutex, critical section or similar 
to access shared data. Those will ensure that the necessary memory 
barriers get inserted.


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