What exactly shared means?

[John Colvin via Digitalmars-d-learn]

On Saturday, 3 January 2015 at 13:33:21 UTC, Ola Fosheim Grøstad 
wrote:
> On Saturday, 3 January 2015 at 12:17:52 UTC, ketmar via 
> Digitalmars-d-learn wrote:
>> why should it? thread locals are... well, local for each 
>> thread. you
>> can't access local of different thread without resorting to 
>> low-level
>> assembly and OS dependent tricks.
>
> Of course you can, anything that is reachable through any chain 
> of pointers/references is effectively "shared", not only the 
> object you explicitly "share".
>
> So when you cast away "shared" then call a function and that is 
> safe in itself, you don't know what happens when someone 
> modifies some function deep down in the call chain later on and 
> access some private pointer chain and possibly retain a pointer 
> to it.
>
> The alternative is to put "shared" on all parameters in 
> libraries or avoid using libraries...

I think you're talking cross-purposes. thread-local as in TLS 
v.s. thread-local as in not-shared.