shared - i need it to be useful

[Timon Gehr]

On 22.10.18 12:26, Timon Gehr wrote:
> ---
> module borked;
> 
> void atomicIncrement(int* p)@system{
>      import core.atomic;
>      atomicOp!("+=",int,int)(*cast(shared(int)*)p,1);
> }
> 
> struct Atomic(T){
>      private T val;
>      void opUnary(string op : "++")() shared @trusted {
>          atomicIncrement(cast(T*)&val);
>      }
> }
> void main()@safe{
>      Atomic!int i;
>      auto a=&[i][0];// was: Atomic!int* a = &i;
>      import std.concurrency;
>      spawn((shared(Atomic!int)* a){ ++*a; }, a);
>      ++i.val; // race
> }
> ---

Obviously, this should have been:

---
module borked;

void atomicIncrement(int*p)@system{
     import core.atomic;
     atomicOp!"+="(*cast(shared(int)*)p,1);
}
struct Atomic(T){
     private T val;
     void opUnary(string op:"++")()shared @trusted{
         atomicIncrement(cast(T*)&val);
     }
}
void main()@safe{
     auto a=new Atomic!int;
     import std.concurrency;
     spawn((shared(Atomic!int)* a){ ++*a; }, a);
     ++a.val; // race
}
---

(I was short on time and had to fix Manu's code because it was not 
actually compilable.)