Why does destructor of global var isn't called?

Steven Schveighoffer schveiguy at gmail.com
Wed Dec 26 14:00:08 UTC 2018


On 12/25/18 3:46 PM, Basilez B. wrote:
> On Tuesday, 25 December 2018 at 19:32:47 UTC, Dru wrote:
>> example:
>> -----------
>>
>> struct A{
>>     int* arr;
>>
>>     ~this() {
>>         writeln("A destruct");
>>     }
>> }
>>
>> static ~this() {
>>     writeln("module destruct");
>> }
>>
>> A a;
>>
>> void main() {
>> }
>>
>> -----------
>>
>> only prints "module destruct"
> 
> `a`, since declared in the global scope, is constructed at compile-time 
> so its data are in executable dedicated segments (althoufh here it's 
> just equal to A.init) and don't have to be destructed. Add `a = A(null); 
> ` in main and the destructor gets called.

That's the destructor of the temporary, not the `a`. Add a writeln("end 
of main") at the end of main and you will see the destructor is called 
before main exits (while `a` is still alive).

My expectation is that thread-local-storage variables are not destroyed. 
It's definitely an oversight, as things like refcounting would be 
screwed up if a reference is stored there.

However, I think this will take some help from the compiler, and 
possibly we would have to put those destructors in a constructed static 
destructor, since there is no "type" that holds those variables.

This seems like something for which a bug likely already exists, but 
feel free to file one if you don't find it.

-Steve


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