toStringz lifetime

Ali Çehreli acehreli at
Sun Oct 25 10:37:53 UTC 2020

On 10/25/20 3:19 AM, rikki cattermole wrote:
> On 25/10/2020 11:03 PM, Ali Çehreli wrote:
>> Does the GC see that local variable 'name' that is on the C side? What 
>> I don't know is whether the GC is aware only of the stack frames of D 
>> functions or the entire thread, which would include the C caller's 
>> 'name'.
> The thread stack frame that is registered with the D GC will know about 
> the D side and may know about the C side.
> It depends on what the C side is doing.
> If the C side went ahead and made a new stack frame via a fiber... it 
> won't know about it. But even if it did, the D stack frame is still 
> alive and pinning that bit of memory.
> Ultimately, if the C side puts that pointer some place like a global or 
> send it to another thread, there are no guarantees that things will play 
> out well.

Thanks. That's reassuring. :) So, as long as the D function documents 
that the C side should make a copy if they want to extend the string's 
lifetime it's their responsibility. And from your description I 
understand that they have time to make that copy.


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