[RFC] 12658_thread.cc randomly fails (on MP machines)

[Paolo Carlini]

Paolo Carlini wrote:

> Point 2- is much more nasty, because implies that *any* locale can be 
> in fact a ref-copy of _S_global or _S_classic! In principle, *every* 
> operation on locales (e.g., also the copy constructor, the assignment 
> operator) can be dangerous and must be protected.
> Therefore, it looks like we have to make a decision: either we add 
> locking bits in a few other places (much better if we can do that with 
> zero overhead in the non-multithreaded case), or we can stay with 
> something simpler.

Well, I think that the above is by and large incorrect: the other 
operations (besides locale::global() and locale::locale(), I mean) do 
*not* access _S_global directly and therefore seem safe. My bad, sorry.

Therefore, the problem must be somewhere else...

Now, I'm tentatively suspecting everything related to the 
locale::locale(const char*) constructor. If I change the original 
testcase as in the attached to avoid that specific constructor but 
otherwise keeping its full complexity, it doesn't fail anymore on 4-way 
machines.

Paolo.

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