Acess variable that was set by thread

[Steven Schveighoffer]

On 8/8/22 10:54 AM, ag0aep6g wrote:
> On Monday, 8 August 2022 at 14:29:43 UTC, Steven Schveighoffer wrote:
>> C has no notion of shared, so it's not the right type. Putting 
>> `shared` on it is kind of lying, and can lead to trouble. Better to be 
>> explicit about what it is.
> 
> Nonsense. Putting `shared` on a shared variable is not "lying". It 
> doesn't matter if C makes the distinction. D does.

If you have all these nice abstractions and careful locking around 
accessing the data, but C doesn't, how is this better? Do you feel safer 
because of this?

> 
>> I'm not saying you should use `__gshared` liberally, or for cases 
>> where you are using this only in D. But to say you should *never* use 
>> it is incorrect.
> 
> If you're clever enough to identify a valid use case for `__gshared` and 
> write correct code with it, then you're clever enough to figure out when 
> not to listen to me.

There's nothing clever. If you want to access C globals, you should use 
`__gshared`, because that's what it is. Using `shared`, isn't going to 
save you at all.

> `__gshared` is about as bad as `-boundscheck=off`. They're both glaring 
> safety holes. But people want to be propper hackers (TM). And propper 
> hackers know how to handle these foot-guns, of course. And then they 
> shoot their feet off.

Using `__gshared` to share data with C is as safe as using 
`-boundscheck=on` and sending the array into C which has no such 
restrictions.

The conclusion here really should just be, don't use C.

-Steve