string concatenation

[bearophile]

dnewbie:

>    string s = toUTF8(v) ~ ", world!";
>    MessageBoxA(null, s.toStringz, "myapp", MB_OK);
>    return 0;
> }

I suggest to compile all your code with -property plus -w (or 
-wi), unless you have some specific needs to not do it.

Bye,
bearophile