Re: How check if destructor has been called?

[Christian Köstlin via Digitalmars-d-learn]

On 13.09.22 19:13, Ben Jones wrote:
On Tuesday, 13 September 2022 at 14:06:42 UTC, Injeckt wrote:
Hi, I'm trying to check if destructor has been called, but when I'm 
deleting class object I didn't get any calls from destructor.

myclass.d

    ~this() {
        this.log("\nDestructor\n");
        this._free_trash();
    }


main.d

    try {
        server.server_init(server);
    } catch (Exception e) {
        server.log(e.msg);
        server = null;
    }

Classes are allocated on the GC heap, so even though you're setting the 
reference to null, it's not being collected at that point.  You can use 
`destroy` to make sure the destructor is called (see here: 
https://dlang.org/spec/class.html#destructors)

Or you could make your instance `scope` and then it basically follows 
the same lifetime rules as `struct`s.
Some more things to watch out are mentioned in 
https://p0nce.github.io/d-idioms/#The-trouble-with-class-destructors.

In one of my programs I had problems with allocating in GC called 
destructors (by doing "harmless" writeln debugging).

Kind regards,
Christian