[GiNaC-list] is ginac thread safe for this case?

Jens Vollinga jensv at nikhef.nl
Sun Jun 13 20:37:20 CEST 2010


Am 13.06.2010 20:05, schrieb Alexei Sheplyakov:
>> 4) threads access the same common matrix of expressions, but two threads
>> will never access the same cell.
> This does NOT guarantee that you (or GiNaC on your behalf) won't operate
> on a same (sub)expression from different threads. You *really* need a thread
> safe (or atomic) reference counting to solve this problem.

ah, now I see why we keep arguing: I misread point 4 completely!!! I 
thought he meant to have a clear the separation of expressions between 
threads (matrix and cell as tech-speak synonyms for groups of 
expressions, but NO, he meant really matrices and cells ..., stupid me!).

> As far as I understand GCD code is not any worse in this regard (that said,
> it's not any better either). I might be wrong (I'm just a human being), so
> I'd be grateful if someone could point out any non-reentrant code in GCD
> routines.

Well, someone says: you have static variables inside functions there. A 
thread-switch might occur during the construction, I guess.


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