// a.d
module a;
claas A {
	static myTemplate!A app;

	static this() {
		app = new myTemplate!A;
	}
}

void startup(State s){
	s.app = A.app;
}

// b.d
main(){
	State mainState = new State;

	startup(mainState);
}

The first problem I have is, that I can set a breakpoint on the static constructor but it's never executed. Later on startup() is executed but A.app is NULL. Why is the static constructor not run? I added a shared too, but same problem.

What I want to achieve is, that one instance of A is created on program start-up in a way that I can later use it. Or what's the best practice to instantiate at least one object of a class at startup?

-- 
Robert M. Münch
http://www.saphirion.com
smarter | better | faster

On 2019-05-08 17:37:38 +0000, Robert M. Münch said:

> // a.d
> module a;
> claas A {
> 	static myTemplate!A app;
> 
> 	static this() {
> 		app = new myTemplate!A;
> 	}
> }
> 
> void startup(State s){
> 	s.app = A.app;
> }
> 
> // b.d
> main(){
> 	State mainState = new State;
> 
> 	startup(mainState);
> }
> 
> The first problem I have is, that I can set a breakpoint on the static constructor but it's never executed.

That was because I'm starting the D runtime manually and that call came later.

However, A.app is still NULL even after the static constructor run.

-- 
Robert M. Münch
http://www.saphirion.com
smarter | better | faster

On 2019-05-08 17:47:35 +0000, Robert M. Münch said:

> However, A.app is still NULL even after the static constructor run.

Forget that... I used my (quite complex code, not exactly reflected in the example) not correctly... works now.

-- 
Robert M. Münch
http://www.saphirion.com
smarter | better | faster

On Wednesday, 8 May 2019 at 18:06:35 UTC, Robert M. Münch wrote:

> Forget that... I used my (quite complex code, not exactly reflected in the example) not correctly... works now.

For future reference, it sounds like what you're after is a singleton. There's an example here: https://wiki.dlang.org/Low-Lock_Singleton_Pattern

Instantiation is done with get() instead of this().