Hello,

the code below compiles and runs fine. However, when I change Payload from struct to class I get compiler errors:

Error	1	Error: template instance std.typecons.RefCounted!(Payload, cast(RefCountedAutoInitialize)1) does not match template declaration RefCounted(T, RefCountedAutoInitialize autoInit = RefCountedAutoInitialize.yes) if (!is(T == class))	C:\Users\Nutzer\Windows Ordner\Documents\Visual Studio 2013\Projects\RefCountedScratch\RefCountedScratch\main.d	26	

I tried many things, but nothing did it. Any help appreciated :-).
Thanks, Bienlein


import std.stdio;
import std.typecons;

struct Payload
{
	private int num = 0;

	this(int i)
	{
		num = i;
		writefln("Payload's constructor called");
	}

	~this()
	{
		 writefln("Payload's destructor called");
	}
}



int main(string[] argv)
{
    alias RefCounted!(Payload, RefCountedAutoInitialize.yes) Data;

    int bar = 12;
    Data data = Data(bar);

    return 0;
}

On Monday, 25 August 2014 at 21:14:03 UTC, Bienlein wrote:
> Hello,
>
> the code below compiles and runs fine. However, when I change Payload from struct to class I get compiler errors:
>
> Error	1	Error: template instance std.typecons.RefCounted!(Payload, cast(RefCountedAutoInitialize)1) does not match template declaration RefCounted(T, RefCountedAutoInitialize autoInit = RefCountedAutoInitialize.yes) if (!is(T == class))	C:\Users\Nutzer\Windows Ordner\Documents\Visual Studio 2013\Projects\RefCountedScratch\RefCountedScratch\main.d	26	
>
> I tried many things, but nothing did it. Any help appreciated :-).
> Thanks, Bienlein
>
>
> import std.stdio;
> import std.typecons;
>
> struct Payload
> {
> 	private int num = 0;
>
> 	this(int i)
> 	{
> 		num = i;
> 		writefln("Payload's constructor called");
> 	}
>
> 	~this()
> 	{
> 		 writefln("Payload's destructor called");
> 	}
> }
>
>
>
> int main(string[] argv)
> {
>     alias RefCounted!(Payload, RefCountedAutoInitialize.yes) Data;
>
>     int bar = 12;
>     Data data = Data(bar);
>
>     return 0;
> }

RefCounted does not work with classes. Classes are reference types already.


The key is in the error message ...if(!is(T == class))... restricts the template to non-class types only.

cheers,
uri

On Tuesday, 26 August 2014 at 06:01:25 UTC, uri wrote:

> RefCounted does not work with classes. Classes are reference types already.

Yep, that's the problem. I also got some suspicion, then surfed the Internet and found the information about it. Thanks for explaining the error message to me. Now it even seems obvious to me what it wants to say ;-).

But you can define a var inside a struct that holds a class and this way I got it working with my class as well thanks to generics in D. Woohoo!